Cluster-Randomized Controlled Trial Evaluating the Effectiveness of Computer-Assisted Intervention Delivered by Educators for Children With Speech Sound Disorders Purpose The aim was to evaluate the effectiveness of computer-assisted input-based intervention for children with speech sound disorders (SSD). Method The Sound Start Study was a cluster-randomized controlled trial. Seventy-nine early childhood centers were invited to participate, 45 were recruited, and 1,205 parents and educators of 4- and ... Research Article
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Research Article  |   July 12, 2017
Cluster-Randomized Controlled Trial Evaluating the Effectiveness of Computer-Assisted Intervention Delivered by Educators for Children With Speech Sound Disorders
 
Author Affiliations & Notes
  • Sharynne McLeod
    Charles Sturt University, Bathurst, Australia
  • Elise Baker
    The University of Sydney, Australia
  • Jane McCormack
    Charles Sturt University, Albury, Australia
  • Yvonne Wren
    Bristol Speech and Language Therapy Research Unit, United Kingdom
    University of Bristol, United Kingdom
  • Sue Roulstone
    Bristol Speech and Language Therapy Research Unit, United Kingdom
    University of the West of England, Bristol, United Kingdom
  • Kathryn Crowe
    Charles Sturt University, Sydney, Australia
  • Sarah Masso
    Charles Sturt University, Sydney, Australia
  • Paul White
    University of the West of England, Bristol, United Kingdom
  • Charlotte Howland
    The University of Sydney, Australia
    Charles Sturt University, Sydney, Australia
  • Disclosure: The authors declare that there is no conflict of interest. The authors acknowledge that Yvonne Wren and Sue Roulstone developed the Phoneme Factory Sound Sorter software used in this project; however, they were not directly involved in the implementation of this project, had no contact with participants, and did not participate in data collection or analysis.
    Disclosure: The authors declare that there is no conflict of interest. The authors acknowledge that Yvonne Wren and Sue Roulstone developed the Phoneme Factory Sound Sorter software used in this project; however, they were not directly involved in the implementation of this project, had no contact with participants, and did not participate in data collection or analysis. ×
  • Correspondence to Sharynne McLeod: smcleod@csu.edu.au
  • Editor: Julie Liss
    Editor: Julie Liss×
  • Associate Editor: Amy Neel
    Associate Editor: Amy Neel×
Article Information
Development / Speech, Voice & Prosodic Disorders / School-Based Settings / Research Issues, Methods & Evidence-Based Practice / Normal Language Processing / Speech, Voice & Prosody / Speech / Research Articles
Research Article   |   July 12, 2017
Cluster-Randomized Controlled Trial Evaluating the Effectiveness of Computer-Assisted Intervention Delivered by Educators for Children With Speech Sound Disorders
Journal of Speech, Language, and Hearing Research, July 2017, Vol. 60, 1891-1910. doi:10.1044/2017_JSLHR-S-16-0385
History: Received October 4, 2016 , Revised January 25, 2017 , Accepted February 20, 2017
 
Journal of Speech, Language, and Hearing Research, July 2017, Vol. 60, 1891-1910. doi:10.1044/2017_JSLHR-S-16-0385
History: Received October 4, 2016; Revised January 25, 2017; Accepted February 20, 2017
Web of Science® Times Cited: 3

Purpose The aim was to evaluate the effectiveness of computer-assisted input-based intervention for children with speech sound disorders (SSD).

Method The Sound Start Study was a cluster-randomized controlled trial. Seventy-nine early childhood centers were invited to participate, 45 were recruited, and 1,205 parents and educators of 4- and 5-year-old children returned questionnaires. Children whose parents and educators had concerns about speech were assessed (n = 275); 132 children who were identified with phonological pattern-based errors underwent additional assessment. Children with SSD and no difficulties with receptive language or hearing, typical nonverbal intelligence, and English as their primary language were eligible; 123 were randomized into two groups (intervention n = 65; control n = 58), and 3 withdrew. The intervention group involved Phoneme Factory Sound Sorter software (Wren & Roulstone, 2013) administered by educators over 9 weeks; the control group involved typical classroom practices. Participants were reassessed twice by a speech-language pathologist who was unaware of the initial assessment and intervention conditions.

Results For the primary outcome variable (percentage of consonants correct), the significant mean change from pre- to postintervention for the intervention group (mean change = +6.15, p < .001) was comparable in magnitude to the significant change for the control group (mean change = +5.43, p < .001) with a small between-groups effect size for change (Cohen's d = 0.08). Similar results occurred for measures of emergent literacy, phonological processing, participation, and well-being.

Conclusion Computer-assisted input-based intervention administered by educators did not result in greater improvement than typical classroom practices.

There is a high prevalence of speech sound disorders (SSD) in young children (Eadie et al., 2015; Law, Boyle, Harris, Harkness, & Nye, 2000; Wren, Miller, Peters, Emond, & Roulstone, 2016) and a high number of children with SSD on speech-language pathologists' (SLPs') caseloads (e.g., Broomfield & Dodd, 2004; Mullen & Schooling, 2010). There are, accordingly, many interventions for SSD that are supported by research evidence (for a review, see Baker & McLeod, 2011). However, within real service contexts, the frequency and total number of intervention sessions provided can be limited by available resources (McAllister, McCormack, McLeod, & Harrison, 2011; McCormack & Verdon, 2015; Ruggero, McCabe, Ballard, & Munro, 2012) and service-delivery provisions (McLeod & Baker, 2014). For instance, despite evidence that children with SSD can require approximately 30–40 hr of intervention by SLPs to become intelligible (Hodson, 2007; Williams, 2012), children have been reported to receive an average of 6.2 hr of intervention over 12 months (Glogowska, Roulstone, Enderby, & Peters, 2000), or even less (Ruggero et al., 2012).
In an effort to close the gap between empirically based recommendations regarding intensity of intervention and real-world delivery constraints on speech-language pathology services, some interventions for children with SSD have been tried using alternative models of delivery in which parents or educators deliver intervention with training and guidance from an SLP (Broen & Westman, 1990; Dodd & Barker, 1990; Eiserman, McCoun, & Escobar, 1990; Lancaster, Keusch, Levin, Pring, & Martin, 2010; Ruscello, Cartwright, Haines, & Shuster, 1993). This allows intervention to be delivered more frequently, potentially meeting the needs of children. However, in the limited evidence examining parent- and/or educator-delivered interventions, the outcomes have not always been ideal. Law, Garrett, and Nye (2003)  found in a meta-analysis of interventions for expressive phonology that intervention conditions were associated with better child progress in phonology than were control conditions. However, when parent-administered interventions were removed from the analysis, the effect size increased, suggesting that parent-administered interventions produced less impact on children's speech. For instance, Lancaster et al. (2010)  compared SLP- and parent-delivered intervention with no intervention for 15 preschool children with SSD. The preschool children who received the SLP-delivered intervention made the most improvement. It was unclear whether this improvement was due to the difference in the intervention agent (SLP vs. parent) or the difference in the intervention—the SLPs delivered their own “eclectic” intervention involving speech-production practice, auditory tasks, and phonological awareness, whereas the parents implemented “auditory input and bombardment activities that related to their child's error patterns” (Lancaster et al., 2010, p. 178). Dodd and Barker (1990)  examined parent- and teacher-delivered minimal-pair intervention for 11 preschool children with SSD. Although an improvement was detected for both the parent- and teacher-implemented interventions, the improvement was described as limited for the children who received the teacher-delivered intervention. Two barriers to implementation were identified: lack of time and intervention-agent capability. The researchers noted that despite the teachers receiving approximately 24 hr of extensive training, they did not attain similar results to parent-delivered intervention. One way to circumvent this barrier is to make the intervention simpler and easier to implement through the use of computer technology.
In a systematic review of computer-based interventions for children and adults with articulation and phonological disorders, Chen et al. (2016)  noted that such interventions can be effective. Unlike inexperienced intervention agents, computers can be programed to provide accurate and consistent feedback, thus circumventing barriers to implementation noted by Dodd and Barker (1990) . Ruscello et al. (1993)  discovered this to be the case when they found that computer-based minimal-pair intervention delivered by a parent was just as effective as direct speech-language pathology intervention at improving children's speech. This study was small (12 participants), and the parents needed to attend the speech-language pathology clinic in order to access the computer program to provide the intervention. Given that the time spent training parents benefits their children, it would seem advantageous to train educators, because they could expand their knowledge and skills to more children (Dodd & Barker, 1990). However, it is unknown whether computer-based intervention delivered by educators in a preschool setting would yield similar positive results to that delivered by parents. It is also unknown whether such an intervention could help prepare preschool children with SSD for future literacy instruction. This idea has appeal, because children with SSD are at risk of literacy difficulties (Anthony et al., 2011).
Models of language processing have typically identified a common pathway between speech and literacy development (Duggirala & Dodd, 1991; Kay, Lesser, & Coltheart, 1992; Stackhouse & Wells, 1997), which helps explain why difficulties in these two areas commonly coexist. What is less clear is whether differing presentations or subtypes of SSD can be identified that have distinct pathways and require different interventions. Waring and Knight (2013)  identified three approaches to classification of SSD on the bases of etiology (Shriberg et al., 2010), linguistics (Dodd, 2013), and processing skills (Stackhouse & Wells, 1997). Each approach offers alternate ways of conceptualizing SSD and identifying approaches to intervention. Whereas the approaches proposed by Shriberg et al. (2010)  and Dodd (2013)  offer categorical subtypes, Stackhouse and Wells (1997)  proposed a system that links a plausible underlying processing cause with speech output. To be more specific, they proposed three core elements: input processes (i.e., detecting and perceiving speech or seeing a written word or letter), cognitive–linguistic processes (i.e., creating, storing, and accessing lexical representations of words comprising semantic, phonological, grammatical, orthographic, and/or motor information), and output processes (i.e., producing speech or writing a word or letter). Some children with phonologically based SSD (i.e., those who show error patterns affecting classes of sounds and/or phonotactics) are thought to have underspecified or poor-quality phonological representations as a result of difficulties with input (perceptual) and cognitive–linguistic processes (e.g., Munson, Baylis, Krause, & Yim, 2010; Sutherland & Gillon, 2005). Their underspecified phonological representations are thought to manifest in inaccurate speech and poor performance on tasks involving phonological awareness (Sutherland & Gillon, 2007). An intervention approach that targets input-processing skills and phonological awareness could therefore result in improvements to a child's speech where the core deficit involves these areas of processing.
This is indeed what Gillon (2005)  discovered. Through targeting phonological error patterns via speech-production practice, alongside an emergent-literacy intervention targeting phoneme awareness and letter knowledge, 12 preschoolers with phonologically based SSD became intelligible and successful readers and spellers. Gillon suggested that the phoneme-awareness and letter-knowledge activities might have helped the children's speech because they helped to establish “more fully specified underlying phonological representations” (p. 321). The intervention involved input and output tasks and was delivered by an SLP, or a student under the supervision of a qualified SLP, twice weekly in one individual session and one small-group session over an average of 25.5 hr. Three of the 12 children needed an additional 10–12 hr of intervention to improve their intelligibility.
A computer-based intervention program designed to target the input-processing and phonological-awareness skills of children with SSD is Phoneme Factory Sound Sorter (PFSS; Wren & Roulstone, 2006, 2013). PFSS comprises seven interactive games that can be customized to a child's needs on the basis of their errors in speech sound production and underlying processing skills. The games require children to listen and respond to visual and auditory stimuli and specifically target phoneme segmentation and identification, phoneme blending, minimal-pair discrimination, and rhyme detection. The PFSS software allows the user to select specific phoneme targets and goals as well as word types (nonwords, real words), word position (initial, medial, final), and stimulus options (sound on/off, picture on/off), and to modify what is selected from session to session in light of a child's response to intervention—a setup known as the free configuration setting. The free configuration setting requires expertise to probe for phonological generalization and change what is being targeted and/or played in light of a child's response to intervention. PFSS was also designed with predetermined configuration settings—known as the teacher settings. These settings comprise seven preset modules for children who present with common developmental phonological error patterns (i.e., stopping, final-consonant deletion, velar fronting, gliding, context-sensitive voicing, deaffrication, cluster reduction). These preset teacher settings consist of four to seven sessions of activities. Each session contains three to five games that have been configured to target the pattern, with each game being played multiple times across the sessions but with increasing complexity in their configuration.
Wren and Roulstone (2008)  compared the effects of 12 hr of an experimental version of PFSS with those of conventional tabletop intervention (targeting input processing and phonological awareness) and no intervention (n = 33, with 11 randomly assigned to each group). Participants received three sessions a week over 8 weeks, each session lasting 30 min. One session a week was delivered by the SLP with a teaching assistant observing. The teaching assistant then delivered the other two sessions each week. The free configuration setting was used rather than the teacher settings, allowing the SLP to select the most appropriate targets and stimuli for each child from session to session. The researchers discovered that although there was not a statistically significant difference between the groups, the preschool children who received the PFSS intervention showed a trend toward more improvement compared with the children in the control group. This occurred when the children were stimulable for the target sounds prior to intervention and showed developmental rather than nondevelopmental error patterns. Because these were the same processes targeted via the preset teacher settings, it was hypothesized that the same results could perhaps be achieved with the tool being delivered by non-SLPs. The effects of the intervention on the children's emergent-literacy skills (i.e., phonological awareness and print knowledge) and phonological processing (i.e., ability to rapidly retrieve stored words from memory and recall information) were not measured. The potential for intervention to indirectly address the impact of SSD on children's everyday well-being (i.e., activity and participation) was also not considered.
It was speculated that a larger scale study, conducted for a longer period of time and using non-SLPs, would yield clearer insight into the potential of PFSS to improve children's speech, emergent literacy, phonological processing, and well-being. However, for PFSS to be implemented easily, the teacher settings (rather than free configuration setting) would need to be used, and children with developmental rather than nondevelopmental phonological error patterns selected. In light of research examining the effect of intervention intensity for children with SSD (Allen, 2013; Williams, 2012), PFSS would also need to be implemented with an adequate and feasible intensity, including dose, session frequency, and total intervention duration (Baker, 2012; Warren, Fey, & Yoder, 2007).
There is no clear answer as to what constitutes adequate and feasible intensity in intervention for children with SSD. The majority of peer-reviewed published intervention research (94% of 134 studies) for children with SSD reports intervention outcomes for a predetermined period of time rather than from referral to dismissal (Baker & McLeod, 2011). This is often because of constraints within a research context, such as the time and funds available to conduct intervention research. This creates a challenge—conducting experimental research within the confines of a budget, with a feasible session dose, duration, and frequency for a period of time sufficient to demonstrate a clinically significant effect. Across a selection of peer-reviewed published intervention studies involving children with SSD using predetermined time periods and a robust randomized controlled trial design, positive effects have been reported for 30-min. sessions scheduled three times weekly over 8 weeks (i.e., 24 sessions; Allen, 2013), 12 weekly 30-min. sessions (Dodd et al., 2008), and 16 twice-weekly 1-hr sessions over 8 weeks (Ruscello et al., 1993). Together, these studies suggest that twice-weekly 60-min. sessions (or four 30-min. sessions each week) over approximately 8–12 weeks may be sufficient to demonstrate an effect in a research context.
Aim
The aim of the Sound Start Study was to evaluate the effectiveness of PFSS delivered by educators (using the teacher settings) compared with typical classroom practices on the speech production, emergent literacy, phonological processing, and participation and well-being of 4- to 5-year-old children with phonologically based SSD.
Method
Participant Recruitment and Eligibility
Seventy-nine early childhood education centers in Sydney, Australia, were invited to be involved in the Sound Start Study between 2013 and 2015, and 45 were recruited. 1   Early childhood education centers were identified by geographical location (postcode) in order to obtain a sample of children living in a range of socioeconomic advantage and disadvantage. Private (n = 7), community (n = 9), government-funded (n = 24), and local-council-funded (n = 5) early childhood education centers were included in the sample. Directors of the early childhood education centers agreeing to participate in the study were asked to distribute screening questionnaires to parents of all 4- to 5-year-old children within their center (n = 1,920).
The Sound Start Study was undertaken in six stages, with recruitment occurring over 3 years (see Figure 1). Eleven sites participated during more than one year. In Stage 1, parent and educator screening questionnaires were returned for 1,205 4- to 5-year-old children attending one of the 45 early childhood education centers. In Stage 2, 275 children whose parents and/or educators were concerned about how they “talked and made speech sounds” (Glascoe, 2000) were directly assessed to screen their eligibility for the trial. In Stage 3, 132 eligible children received a more comprehensive assessment. Data from Stages 2 and 3 were gathered preintervention and served as baseline measures. At the end of Stage 3, there were 123 children at 39 sites who were eligible for intervention in Stage 4. The early childhood education centers with eligible children were randomized to the intervention (n = 19 sites, 65 children) and control (n = 20 sites, 58 children) conditions. Computerized intervention using PFSS was provided to 63 eligible children in the intervention condition. Fifty-seven children received the control condition of typical classroom practices—that is, they continued to participate in their classroom environment as usual without any input from the researchers. Three children withdrew from the study. In Stage 5, immediate follow-up assessments were undertaken with 113 children. In Stage 6, long-term follow-up assessments were conducted with 114 children 6–8 weeks later. Data from Stages 5 and 6 were gathered postintervention and served as outcome measures. All direct assessments (pre- and postintervention) were completed in a quiet room within the early childhood education centers, except nine Stage 6 (Year 1) assessments that were completed at the children's homes during the school holidays, due to the children's availability. This article reports data from Stages 1–6 (screening, baseline, intervention, and outcome), with a particular emphasis on the baseline (Stages 2 and 3), intervention (Stage 4), and outcome measures (Stages 5 and 6). Some data regarding Stage 1 are reported by McLeod, Crowe, McCormack, et al. (2017), and Stages 2 and 3 by McLeod, Crowe, Masso, et al. (2017) .
Figure 1.

Participant recruitment and randomization flow diagram. SLP = speech-language pathologist.

 Participant recruitment and randomization flow diagram. SLP = speech-language pathologist.
Figure 1.

Participant recruitment and randomization flow diagram. SLP = speech-language pathologist.

×
Children's eligibility was determined across Stages 1–3. The criteria for eligibility are shown in Table 1. In summary, children were eligible for the randomized controlled trial (Stage 4) if they were identified as having SSD that included a phonological pattern that could be treated by the preset teacher settings on PFSS; were not reported to have a cleft lip or palate, developmental delay, or persistent hearing loss; and were found to have no difficulties with nonverbal intelligence, oromusculature, hearing, and receptive language during direct assessment. 2   Children who spoke languages in addition to English were included; however, their English language skills had to be equivalent to or better than their skills in the other language(s).
Table 1. Eligibility criteria from Stages 1, 2, and 3 for inclusion in Stage 4 (intervention/control) of the Sound Start Study.
Eligibility criteria from Stages 1, 2, and 3 for inclusion in Stage 4 (intervention/control) of the Sound Start Study.×
Stage Skill Criteria Assessment tool Informant
1: Screening for eligibility by parents/teacher Speech Difficulty talking and making speech sounds (yes or a little concerned) Parents' Evaluation of Developmental Status (Glascoe, 2000) Parent and/or teacher
Speech Speech not clear to family and/or others Parent questionnaire a Parent and/or teacher
Medical and developmental history Reported no persistent hearing loss, cleft lip or palate, or developmental delay Parent questionnaire a Parent and/or teacher
English language use English language skills had to be equivalent to or better than their skills in the other language Parent questionnaire Parent
2: Assessment for eligibility following direct screening assessment by speech-language pathologist Speech Percentage of consonants correct standard score ≤ 6 (i.e., greater than 1 SD below the mean) Diagnostic Evaluation of Articulation and Phonology, Phonology Assessment (Dodd et al., 2002) Direct assessment
Had a phonological pattern that could be treated by PFSS
Nonverbal intelligence Year 1: Nonverbal Index Score > 79 (percentile rank of > 8); Years 2 and 3: Nonverbal Index Score > 70 (percentile rank of > 2). Primary Test of Nonverbal Intelligence (Ehrler & McGhee, 2008) Direct assessment
3: Assessment for eligibility following direct comprehensive assessment by speech-language pathologist Receptive vocabulary Receptive vocabulary score less than 2 SDs below the mean Peabody Picture Vocabulary Test–Fourth Edition (Dunn & Dunn, 2007) Direct assessment
Hearing Passed hearing screening of all frequencies at 40 dB during Stage 2 or Stage 3 Pure-tone audiometry (500, 1000, 2000, 4000 Hz) at 40 dB, adjusted for noisy environments (American Speech-Language-Hearing Association, 1985) Direct assessment
Note. PFSS = Phoneme Factory Sound Sorter.
Note. PFSS = Phoneme Factory Sound Sorter.×
a Question used with permission from Longitudinal Study of Australian Children (Australian Institute of Family Studies, 2007).
Question used with permission from Longitudinal Study of Australian Children (Australian Institute of Family Studies, 2007).×
Table 1. Eligibility criteria from Stages 1, 2, and 3 for inclusion in Stage 4 (intervention/control) of the Sound Start Study.
Eligibility criteria from Stages 1, 2, and 3 for inclusion in Stage 4 (intervention/control) of the Sound Start Study.×
Stage Skill Criteria Assessment tool Informant
1: Screening for eligibility by parents/teacher Speech Difficulty talking and making speech sounds (yes or a little concerned) Parents' Evaluation of Developmental Status (Glascoe, 2000) Parent and/or teacher
Speech Speech not clear to family and/or others Parent questionnaire a Parent and/or teacher
Medical and developmental history Reported no persistent hearing loss, cleft lip or palate, or developmental delay Parent questionnaire a Parent and/or teacher
English language use English language skills had to be equivalent to or better than their skills in the other language Parent questionnaire Parent
2: Assessment for eligibility following direct screening assessment by speech-language pathologist Speech Percentage of consonants correct standard score ≤ 6 (i.e., greater than 1 SD below the mean) Diagnostic Evaluation of Articulation and Phonology, Phonology Assessment (Dodd et al., 2002) Direct assessment
Had a phonological pattern that could be treated by PFSS
Nonverbal intelligence Year 1: Nonverbal Index Score > 79 (percentile rank of > 8); Years 2 and 3: Nonverbal Index Score > 70 (percentile rank of > 2). Primary Test of Nonverbal Intelligence (Ehrler & McGhee, 2008) Direct assessment
3: Assessment for eligibility following direct comprehensive assessment by speech-language pathologist Receptive vocabulary Receptive vocabulary score less than 2 SDs below the mean Peabody Picture Vocabulary Test–Fourth Edition (Dunn & Dunn, 2007) Direct assessment
Hearing Passed hearing screening of all frequencies at 40 dB during Stage 2 or Stage 3 Pure-tone audiometry (500, 1000, 2000, 4000 Hz) at 40 dB, adjusted for noisy environments (American Speech-Language-Hearing Association, 1985) Direct assessment
Note. PFSS = Phoneme Factory Sound Sorter.
Note. PFSS = Phoneme Factory Sound Sorter.×
a Question used with permission from Longitudinal Study of Australian Children (Australian Institute of Family Studies, 2007).
Question used with permission from Longitudinal Study of Australian Children (Australian Institute of Family Studies, 2007).×
×
Participants in the Randomized Controlled Trial
Participants in the randomized controlled trial were 123 children who were eligible for intervention in Stage 4 of the Sound Start Study. They ranged in age from 4;0 (years;months) to 5;4 (M = 4;6; SD = 4.2) when they were assessed at Stage 3 (see Table 2). There were more boys (n = 79, 64.2%) than girls (n = 44, 35.8%). The participants lived in a range of suburbs from the most disadvantaged (first decile) to most advantaged (10th decile) according to the Australian Index of Relative Socioeconomic Advantage and Disadvantage (IRSAD), which considers “people's access to material and social resources, and their ability to participate in society” (Pink, 2008, p. 17). The mean IRSAD decile of participants was 5.97 (SD = 3.2), with a mode of 8 (25th percentile = 3, 50th percentile = 7, 75th percentile = 8). Information about family IRSAD was available for all participants. The majority of participants (n = 114) were reported to use English at home (107 spoke only English at home, and seven spoke English and an additional language at home). Nine participants spoke a language other than English at home. The parents of most (n = 120) of the participants described their child's English language proficiency. The majority were described by their parents as using English “very well” (n = 64, 52.0%), with fewer parents reporting “somewhat well” (n = 48, 39%) or “not very well” (n = 8, 6.5%). According to their parents, the participants spoke one (n = 100, 81.3%), two (n = 21, 17.1%), or three (n = 2, 1.6%) languages, with 17 languages reported in total. The languages in addition to English were Arabic, Cantonese, Filipino, Greek, Hindi, Indonesian, Korean, Malayalam, Maltese, Marathi, Portuguese, Punjabi, Spanish, Tamil, Thai, and Urdu.
Table 2. Characteristics of the intervention and control groups in the Sound Start Study (n = 123) prior to intervention.
Characteristics of the intervention and control groups in the Sound Start Study (n = 123) prior to intervention.×
Parameter Measure Valid n Intervention group Control group Significant difference (p)
Age, M (SD) Months 123 55.3 (4.1) 56.9 (4.3) .044
Sex, n (%) Male 79 43 (66.2) 36 (62.1) .637
Female 44 22 (33.8) 22 (37.9)
Multilingual status, n (%) English only 100 52 (80.0) 48 (82.8) .695
Multilingual 23 13 (20.0) 10 (17.2)
Socioeconomic status, M (SD) IRSAD 123 6.2 (2.9) 5.8 (3.5) .495
Speech severity, M (SD) DEAP percentage of consonants correct 123 68.15 (9.90) 63.19 (13.76) .022
Consonant stimulability, M (SD) Number of English consonants out of 24 123 22.3 (1.8) 22.0 (1.9) .338
Phonological awareness, M (SD) CTOPP-2 Phonological Awareness composite score 122 89.0 (11.5) 87.4 (10.4) .432
Nonverbal IQ, M (SD) PTONI raw score 123 22.4 (8.8) 22.0 (8.9) .788
Receptive vocabulary, M (SD) PPVT-4 raw score 123 68.1 (18.3) 71.5 (19.2) .309
Note. IRSAD = Index of Relative Socioeconomic Advantage and Disadvantage; DEAP = Diagnostic Evaluation of Articulation and Phonology; CTOPP-2 = Comprehensive Test of Phonological Processing–Second Edition; PTONI = Primary Test of Nonverbal Intelligence; PPVT-4 = Peabody Picture Vocabulary Test–Fourth Edition.
Note. IRSAD = Index of Relative Socioeconomic Advantage and Disadvantage; DEAP = Diagnostic Evaluation of Articulation and Phonology; CTOPP-2 = Comprehensive Test of Phonological Processing–Second Edition; PTONI = Primary Test of Nonverbal Intelligence; PPVT-4 = Peabody Picture Vocabulary Test–Fourth Edition.×
Table 2. Characteristics of the intervention and control groups in the Sound Start Study (n = 123) prior to intervention.
Characteristics of the intervention and control groups in the Sound Start Study (n = 123) prior to intervention.×
Parameter Measure Valid n Intervention group Control group Significant difference (p)
Age, M (SD) Months 123 55.3 (4.1) 56.9 (4.3) .044
Sex, n (%) Male 79 43 (66.2) 36 (62.1) .637
Female 44 22 (33.8) 22 (37.9)
Multilingual status, n (%) English only 100 52 (80.0) 48 (82.8) .695
Multilingual 23 13 (20.0) 10 (17.2)
Socioeconomic status, M (SD) IRSAD 123 6.2 (2.9) 5.8 (3.5) .495
Speech severity, M (SD) DEAP percentage of consonants correct 123 68.15 (9.90) 63.19 (13.76) .022
Consonant stimulability, M (SD) Number of English consonants out of 24 123 22.3 (1.8) 22.0 (1.9) .338
Phonological awareness, M (SD) CTOPP-2 Phonological Awareness composite score 122 89.0 (11.5) 87.4 (10.4) .432
Nonverbal IQ, M (SD) PTONI raw score 123 22.4 (8.8) 22.0 (8.9) .788
Receptive vocabulary, M (SD) PPVT-4 raw score 123 68.1 (18.3) 71.5 (19.2) .309
Note. IRSAD = Index of Relative Socioeconomic Advantage and Disadvantage; DEAP = Diagnostic Evaluation of Articulation and Phonology; CTOPP-2 = Comprehensive Test of Phonological Processing–Second Edition; PTONI = Primary Test of Nonverbal Intelligence; PPVT-4 = Peabody Picture Vocabulary Test–Fourth Edition.
Note. IRSAD = Index of Relative Socioeconomic Advantage and Disadvantage; DEAP = Diagnostic Evaluation of Articulation and Phonology; CTOPP-2 = Comprehensive Test of Phonological Processing–Second Edition; PTONI = Primary Test of Nonverbal Intelligence; PPVT-4 = Peabody Picture Vocabulary Test–Fourth Edition.×
×
Instruments
Questionnaires for Parents
Parents were asked to complete questionnaires created by the research team at each stage. The questionnaires focused on different areas, including parents' concern about their children's development, demographic information, languages spoken, developmental history, family history of speech and language difficulties, home literacy, home computer use, reading skills, and communication skills. The questionnaires included questions created by the researchers as well as ones from previously published scales that were included after permission was gained from the authors of those scales (e.g., Parents' Evaluation of Developmental Status; Glascoe, 2000). Questions were typically asked once; however, some key questions were repeated at different stages. For example, at each stage parents were asked to provide information regarding previous and current speech-language pathology assessment and intervention (in addition to the intervention received during the Sound Start Study).
Questionnaires for Directors and Educators at the Early Childhood Education Centers
Directors of all participating centers completed a 22-item questionnaire that focused on different aspects of the environment, staffing, and use of resources at their center. Directors were asked to describe the number of qualified staff and teaching assistants at the center each day, the organizational basis for the center, parent engagement practices, daily activities, and access, use, and attitudes toward technology at the center.
Instruments Used for Baseline and Outcome Measures
Baseline measures from Stages 2 and 3 and outcome measures from Stages 5 and 6 are described in the following (for the complete assessment protocol, see McLeod, Crowe, Masso, et al., 2017). The stage when assessments were administered is shown in Tables 3 and 4. Each outcome measure pertains to the individual-participant level.
Table 3. Outcomes of the intervention and control groups in the Sound Start Study: Intention to treat (complete cases).
Outcomes of the intervention and control groups in the Sound Start Study: Intention to treat (complete cases).×
Parameter Measure Group Valid n Stage 2/3, M (SD) Stage 5, M (SD) Stage 6, M (SD) Effect F p ηp 2
Speech production
 Percentage of consonants correct DEAP Intervention 59 69.25 (9.13) 75.40 (10.27) 76.06 (9.99) Stage 42.36 < .001 .287
Control 48 64.34 (11.74) 69.77 (12.97) 71.14 (12.78) Group 6.98 .009 .062
Interaction 0.14 .874 .001
 Primary intervention target: Probes Sound Start Study probes Intervention 59 71.27 (25.72) 47.14 (38.12) 43.28 (36.02) Stage 48.79 < .001 .319
Control 47 73.30 (28.35) 57.41 (36.49) 48.19 (36.22) Group 0.99 .322 .009
Interaction 1.12 .329 .011
 Intelligibility ICS Intervention 30 3.75 (0.36) 3.95 (0.39) 3.97 (0.45) Stage 4.14 .019 .094
Control 14 3.90 (0.38) 4.06 (0.48) 4.01 (0.28) Group 0.84 .365 .021
Interaction 0.32 .726 .008
Emergent literacy
 Letter knowledge Anthony et al. (2011)  Intervention 44 8.02 (8.58) 10.95 (9.41) 11.75 (9.40) Stage 19.18 < .001 .186
Control 42 5.95 (7.96) 6.90 (8.82) 9.02 (9.43) Group 2.61 .110 .030
Interaction 1.68 .190 .020
 Word and print awareness PWPA Intervention 59 6.24 (3.43) 7.59 (2.75) Stage 62.31 < .001 .368
Control 51 5.69 (3.09) 7.29 (3.16) Group 0.03 .858 .000
Interaction 3.84 .053 .035
 Phonological awareness: Elision CTOPP-2 Intervention 55 2.58 (4.36) 3.38 (3.83) 3.91 (4.11) Stage 19.99 < .001 .172
Control 43 3.02 (3.83) 4.19 (3.86) 5.37 (3.96) Group 1.41 .238 .014
Interaction 1.59 .208 .016
 Phonological awareness: Blending Words CTOPP-2 Intervention 55 4.09 (4.02) 5.33 (4.54) 6.07 (4.62) Stage 21.44 < .001 .181
Control 44 3.66 (3.14) 5.61 (3.40) 5.77 (3.87) Group 0.04 .837 .000
Interaction 0.68 .509 .007
 Phonological awareness: Sound Matching CTOPP-2 Intervention 56 3.88 (3.30) 4.45 (3.56) 5.77 (3.87) Stage 1.40 .249 .014
Control 43 4.09 (3.28) 3.93 (2.52) 4.33 (3.14) Group 0.32 .573 .003
Interaction 0.66 .518 .007
Phonological processing
 Phonological memory: Memory for Digits CTOPP-2 Intervention 55 10.44 (2.86) 11.33 (2.99) 11.60 (2.65) Stage 7.92 < .001 .077
Control 42 11.50 (3.19) 11.88 (3.62) 12.40 (2.58) Group 2.32 .131 .024
Interaction 0.47 .624 .005
 Phonological memory: Nonword Repetition CTOPP-2 Intervention 55 2.65 (2.78) 3.62 (3.75) 3.75 (3.64) Stage 5.81 .004 .057
Control 43 2.49 (3.31) 4.05 (3.63) 3.65 (3.41) Group 0.01 .914 .000
Interaction 0.01 .727 .003
 Rapid nonsymbolic naming: Rapid Color Naming CTOPP-2 Intervention 34 58.29 (18.86) 54.94 (20.13) 56.76 (21.95) Stage 3.47 .035 .060
Control 22 58.00 (15.58) 51.14 (12.88) 52.68 (16.35) Group 0.37 .548 .007
Interaction 0.57 .567 .010
 Rapid nonsymbolic naming: Rapid Object Naming CTOPP-2 Intervention 41 64.02 (19.77) 63.44 (21.20) 65.41 (23.44) Stage 0.96 .384 .013
Control 34 62.38 (12.61) 62.18 (17.49) 64.35 (18.82) Group 0.10 .749 .001
Interaction 0.02 .983 .000
Children’s participation and well-being
 Parent-reported communication outcomes FOCUS Intervention 29 253.4 (49.25) 256.8 (52.68) 261.1 (49.57) Stage 1.83 .167 .042
Control 15 256.5 (38.09) 269.2 (38.36) 267.5 (49.69) Group 0.27 .606 .006
Interaction 0.41 .668 .010
 Child-reported attitude score KiddyCAT Intervention 57 3.68 (2.42) 3.23 (2.61) 2.26 (2.39) Stage 7.99 < .001 .073
Control 46 3.76 (2.48) 3.61 (2.94) 3.15 (2.37) Group 1.25 .267 .012
Interaction 1.24 .292 .012
 Child-reported happy Image Not Available occurrences SPAA-C Intervention 56 6.95 (2.76) 6.41 (2.38) 5.90 (2.62) Stage 1.62 .200 .016
Control 44 5.60 (3.04) 5.87 (2.71) 5.64 (2.60) Group 3.13 .080 .030
Interaction 1.91 .151 .018
Note. DEAP = Diagnostic Evaluation of Articulation and Phonology, Phonology Assessment; ICS = Intelligibility in Context Scale; PWPA = Preschool Word and Print Awareness; CTOPP-2 = Comprehensive Test of Phonological Processing–Second Edition; FOCUS = Focus on the Outcomes of Children Under Six; KiddyCAT = Communication Attitude Test for Preschool and Kindergarten Children Who Stutter; SPAA-C = Speech Participation and Activity Assessment of Children.
Note. DEAP = Diagnostic Evaluation of Articulation and Phonology, Phonology Assessment; ICS = Intelligibility in Context Scale; PWPA = Preschool Word and Print Awareness; CTOPP-2 = Comprehensive Test of Phonological Processing–Second Edition; FOCUS = Focus on the Outcomes of Children Under Six; KiddyCAT = Communication Attitude Test for Preschool and Kindergarten Children Who Stutter; SPAA-C = Speech Participation and Activity Assessment of Children.×
Table 3. Outcomes of the intervention and control groups in the Sound Start Study: Intention to treat (complete cases).
Outcomes of the intervention and control groups in the Sound Start Study: Intention to treat (complete cases).×
Parameter Measure Group Valid n Stage 2/3, M (SD) Stage 5, M (SD) Stage 6, M (SD) Effect F p ηp 2
Speech production
 Percentage of consonants correct DEAP Intervention 59 69.25 (9.13) 75.40 (10.27) 76.06 (9.99) Stage 42.36 < .001 .287
Control 48 64.34 (11.74) 69.77 (12.97) 71.14 (12.78) Group 6.98 .009 .062
Interaction 0.14 .874 .001
 Primary intervention target: Probes Sound Start Study probes Intervention 59 71.27 (25.72) 47.14 (38.12) 43.28 (36.02) Stage 48.79 < .001 .319
Control 47 73.30 (28.35) 57.41 (36.49) 48.19 (36.22) Group 0.99 .322 .009
Interaction 1.12 .329 .011
 Intelligibility ICS Intervention 30 3.75 (0.36) 3.95 (0.39) 3.97 (0.45) Stage 4.14 .019 .094
Control 14 3.90 (0.38) 4.06 (0.48) 4.01 (0.28) Group 0.84 .365 .021
Interaction 0.32 .726 .008
Emergent literacy
 Letter knowledge Anthony et al. (2011)  Intervention 44 8.02 (8.58) 10.95 (9.41) 11.75 (9.40) Stage 19.18 < .001 .186
Control 42 5.95 (7.96) 6.90 (8.82) 9.02 (9.43) Group 2.61 .110 .030
Interaction 1.68 .190 .020
 Word and print awareness PWPA Intervention 59 6.24 (3.43) 7.59 (2.75) Stage 62.31 < .001 .368
Control 51 5.69 (3.09) 7.29 (3.16) Group 0.03 .858 .000
Interaction 3.84 .053 .035
 Phonological awareness: Elision CTOPP-2 Intervention 55 2.58 (4.36) 3.38 (3.83) 3.91 (4.11) Stage 19.99 < .001 .172
Control 43 3.02 (3.83) 4.19 (3.86) 5.37 (3.96) Group 1.41 .238 .014
Interaction 1.59 .208 .016
 Phonological awareness: Blending Words CTOPP-2 Intervention 55 4.09 (4.02) 5.33 (4.54) 6.07 (4.62) Stage 21.44 < .001 .181
Control 44 3.66 (3.14) 5.61 (3.40) 5.77 (3.87) Group 0.04 .837 .000
Interaction 0.68 .509 .007
 Phonological awareness: Sound Matching CTOPP-2 Intervention 56 3.88 (3.30) 4.45 (3.56) 5.77 (3.87) Stage 1.40 .249 .014
Control 43 4.09 (3.28) 3.93 (2.52) 4.33 (3.14) Group 0.32 .573 .003
Interaction 0.66 .518 .007
Phonological processing
 Phonological memory: Memory for Digits CTOPP-2 Intervention 55 10.44 (2.86) 11.33 (2.99) 11.60 (2.65) Stage 7.92 < .001 .077
Control 42 11.50 (3.19) 11.88 (3.62) 12.40 (2.58) Group 2.32 .131 .024
Interaction 0.47 .624 .005
 Phonological memory: Nonword Repetition CTOPP-2 Intervention 55 2.65 (2.78) 3.62 (3.75) 3.75 (3.64) Stage 5.81 .004 .057
Control 43 2.49 (3.31) 4.05 (3.63) 3.65 (3.41) Group 0.01 .914 .000
Interaction 0.01 .727 .003
 Rapid nonsymbolic naming: Rapid Color Naming CTOPP-2 Intervention 34 58.29 (18.86) 54.94 (20.13) 56.76 (21.95) Stage 3.47 .035 .060
Control 22 58.00 (15.58) 51.14 (12.88) 52.68 (16.35) Group 0.37 .548 .007
Interaction 0.57 .567 .010
 Rapid nonsymbolic naming: Rapid Object Naming CTOPP-2 Intervention 41 64.02 (19.77) 63.44 (21.20) 65.41 (23.44) Stage 0.96 .384 .013
Control 34 62.38 (12.61) 62.18 (17.49) 64.35 (18.82) Group 0.10 .749 .001
Interaction 0.02 .983 .000
Children’s participation and well-being
 Parent-reported communication outcomes FOCUS Intervention 29 253.4 (49.25) 256.8 (52.68) 261.1 (49.57) Stage 1.83 .167 .042
Control 15 256.5 (38.09) 269.2 (38.36) 267.5 (49.69) Group 0.27 .606 .006
Interaction 0.41 .668 .010
 Child-reported attitude score KiddyCAT Intervention 57 3.68 (2.42) 3.23 (2.61) 2.26 (2.39) Stage 7.99 < .001 .073
Control 46 3.76 (2.48) 3.61 (2.94) 3.15 (2.37) Group 1.25 .267 .012
Interaction 1.24 .292 .012
 Child-reported happy Image Not Available occurrences SPAA-C Intervention 56 6.95 (2.76) 6.41 (2.38) 5.90 (2.62) Stage 1.62 .200 .016
Control 44 5.60 (3.04) 5.87 (2.71) 5.64 (2.60) Group 3.13 .080 .030
Interaction 1.91 .151 .018
Note. DEAP = Diagnostic Evaluation of Articulation and Phonology, Phonology Assessment; ICS = Intelligibility in Context Scale; PWPA = Preschool Word and Print Awareness; CTOPP-2 = Comprehensive Test of Phonological Processing–Second Edition; FOCUS = Focus on the Outcomes of Children Under Six; KiddyCAT = Communication Attitude Test for Preschool and Kindergarten Children Who Stutter; SPAA-C = Speech Participation and Activity Assessment of Children.
Note. DEAP = Diagnostic Evaluation of Articulation and Phonology, Phonology Assessment; ICS = Intelligibility in Context Scale; PWPA = Preschool Word and Print Awareness; CTOPP-2 = Comprehensive Test of Phonological Processing–Second Edition; FOCUS = Focus on the Outcomes of Children Under Six; KiddyCAT = Communication Attitude Test for Preschool and Kindergarten Children Who Stutter; SPAA-C = Speech Participation and Activity Assessment of Children.×
×
Table 4. Outcomes of the intervention and control groups in the Sound Start Study: Per protocol.
Outcomes of the intervention and control groups in the Sound Start Study: Per protocol.×
Parameter Measure Group Valid n Stage 2/3, M (SD) Stage 5, M (SD) Stage 6, M (SD) Effect F p ηp 2
Speech production
 Percentage of consonants correct DEAP Intervention 22 72.87 (6.99) 78.28 (7.91) 79.29 (7.77) Stage 28.81 < .001 .324
Control 40 63.74 (11.96) 69.85 (13.88) 70.87 (13.30) Group 9.36 .003 .135
Interaction 0.09 .916 .001
 Primary intervention target: Probes Sound Start Study probes Intervention 22 64.83 (27.81) 45.04 (39.01) 43.44 (37.45) Stage 23.33 < .001 .283
Control 39 71.83 (29.04) 57.86 (37.09) 50.85 (36.36) Group 1.16 .286 .019
Interaction 0.49 .614 .008
 Intelligibility ICS Intervention 10 3.86 (0.42) 4.01 (0.32) 3.87 (0.47) Stage 1.48 .243 .008
Control 9 4.00 (0.43) 4.14 (0.47) 4.02 (0.31) Group 0.84 .372 .047
Interaction 0.00 .996 .000
Emergent literacy
 Letter knowledge Anthony et al. (2011)  Intervention 18 11.61 (9.56) 15.17 (9.54) 16.00 (9.59) Stage 13.27 < .001 .206
Control 35 5.74 (8.03) 7.11 (9.08) 9.31 (9.51) Group 7.63 .008 .130
Interaction 1.00 .371 .019
 Word and print awareness PWPA Intervention 22 6.50 (3.43) 7.23 (3.28) Stage 11.73 .001 .159
Control 42 5.50 (3.15) 7.12 (3.25) Group 0.50 .483 .008
Interaction 1.69 .198 .027
 Phonological awareness: Elision CTOPP-2 Intervention 22 2.23 (3.78) 3.32 (4.89) 3.36 (4.26) Stage 15.16 < .001 .216
Control 35 3.06 (4.06) 4.29 (4.00) 5.40 (4.22) Group 1.41 .241 .025
Interaction 2.11 .127 .037
 Phonological awareness: Blending Words CTOPP-2 Intervention 22 5.45 (4.70) 7.18 (5.67) 7.64 (4.94) Stage 19.06 < .001 .254
Control 36 3.72 (3.04) 5.64 (3.59) 6.24 (3.75) Group 2.26 .139 .039
Interaction 0.48 .898 .002
 Phonological awareness: Sound Matching CTOPP-2 Intervention 22 4.09 (3.81) 5.45 (4.34) 5.41 (5.39) Stage 3.01 .053 .052
Control 35 3.66 (3.06) 4.03 (2.47) 4.63 (3.14) Group 1.18 .283 .021
Interaction 0.54 .587 .010
Phonological processing
 Phonological memory: Memory for Digits CTOPP-2 Intervention 22 10.50 (3.25) 11.55 (3.10) 11.68 (2.23) Stage 6.14 .003 .100
Control 35 11.23 (3.18) 11.77 (2.96) 12.14 (2.55) Group 0.45 .505 .008
Interaction 0.33 .723 .006
 Phonological memory: Nonword Repetition CTOPP-2 Intervention 22 2.86 (2.95) 4.32 (4.91) 4.36 (3.81) Stage 1.68 .192 .030
Control 35 2.71 (3.42) 4.37 (3.73) 3.31 (3.52) Group 0.88 .353 .016
Interaction 0.67 .514 .012
 Rapid nonsymbolic naming: Rapid Color Naming CTOPP-2 Intervention 15 59.47 (22.53) 52.73 (22.16) 56.00 (24.08) Stage 2.86 .065 .082
Control 19 57.63 (16.09) 51.79 (13.52) 53.58 (17.48) Group 0.09 .771 .003
Interaction 0.04 .961 .001
 Rapid nonsymbolic naming: Rapid Object Naming CTOPP-2 Intervention 16 64.44 (25.88) 62.06 (27.53) 65.94 (29.47) Stage 1.82 .168 .041
Control 29 62.28 (12.79) 60.52 (16.91) 64.72 (19.46) Group 0.07 .790 .002
Interaction 0.05 .827 .001
Children's participation and well-being
 Parent-reported communication outcomes FOCUS Intervention 11 246.6 (49.23) 261.9 (39.04) 253.9 (36.79) Stage 1.07 .355 .056
Control 9 261.4 (25.74) 267.9 (47.03) 261.9 (54.87) Group 0.31 .584 .017
Interaction 0.19 .827 .011
 Child-reported attitude score KiddyCAT Intervention 22 3.32 (2.15) 3.36 (2.26) 2.45 (2.35) Stage 2.93 .057 .047
Control 39 3.87 (2.45) 3.51 (2.86) 3.21 (2.40) Group 0.83 .367 .014
Interaction 0.42 .657 .007
 Child-reported happy Image Not Available occurrences SPAA-C Intervention 21 7.14 (2.74) 6.38 (2.46) 6.00 (2.85) Stage 2.09 .128 .037
Control 36 6.11 (3.04) 6.47 (2.49) 5.72 (2.53) Group 0.48 .493 .009
Interaction 1.09 .341 .019
Note. DEAP = Diagnostic Evaluation of Articulation and Phonology, Phonology Assessment; ICS = Intelligibility in Context Scale; PWPA = Preschool Word and Print Awareness; CTOPP-2 = Comprehensive Test of Phonological Processing–Second Edition; FOCUS = Focus on the Outcomes of Children Under Six; KiddyCAT = Communication Attitude Test for Preschool and Kindergarten Children Who Stutter; SPAA-C = Speech Participation and Activity Assessment of Children.
Note. DEAP = Diagnostic Evaluation of Articulation and Phonology, Phonology Assessment; ICS = Intelligibility in Context Scale; PWPA = Preschool Word and Print Awareness; CTOPP-2 = Comprehensive Test of Phonological Processing–Second Edition; FOCUS = Focus on the Outcomes of Children Under Six; KiddyCAT = Communication Attitude Test for Preschool and Kindergarten Children Who Stutter; SPAA-C = Speech Participation and Activity Assessment of Children.×
Table 4. Outcomes of the intervention and control groups in the Sound Start Study: Per protocol.
Outcomes of the intervention and control groups in the Sound Start Study: Per protocol.×
Parameter Measure Group Valid n Stage 2/3, M (SD) Stage 5, M (SD) Stage 6, M (SD) Effect F p ηp 2
Speech production
 Percentage of consonants correct DEAP Intervention 22 72.87 (6.99) 78.28 (7.91) 79.29 (7.77) Stage 28.81 < .001 .324
Control 40 63.74 (11.96) 69.85 (13.88) 70.87 (13.30) Group 9.36 .003 .135
Interaction 0.09 .916 .001
 Primary intervention target: Probes Sound Start Study probes Intervention 22 64.83 (27.81) 45.04 (39.01) 43.44 (37.45) Stage 23.33 < .001 .283
Control 39 71.83 (29.04) 57.86 (37.09) 50.85 (36.36) Group 1.16 .286 .019
Interaction 0.49 .614 .008
 Intelligibility ICS Intervention 10 3.86 (0.42) 4.01 (0.32) 3.87 (0.47) Stage 1.48 .243 .008
Control 9 4.00 (0.43) 4.14 (0.47) 4.02 (0.31) Group 0.84 .372 .047
Interaction 0.00 .996 .000
Emergent literacy
 Letter knowledge Anthony et al. (2011)  Intervention 18 11.61 (9.56) 15.17 (9.54) 16.00 (9.59) Stage 13.27 < .001 .206
Control 35 5.74 (8.03) 7.11 (9.08) 9.31 (9.51) Group 7.63 .008 .130
Interaction 1.00 .371 .019
 Word and print awareness PWPA Intervention 22 6.50 (3.43) 7.23 (3.28) Stage 11.73 .001 .159
Control 42 5.50 (3.15) 7.12 (3.25) Group 0.50 .483 .008
Interaction 1.69 .198 .027
 Phonological awareness: Elision CTOPP-2 Intervention 22 2.23 (3.78) 3.32 (4.89) 3.36 (4.26) Stage 15.16 < .001 .216
Control 35 3.06 (4.06) 4.29 (4.00) 5.40 (4.22) Group 1.41 .241 .025
Interaction 2.11 .127 .037
 Phonological awareness: Blending Words CTOPP-2 Intervention 22 5.45 (4.70) 7.18 (5.67) 7.64 (4.94) Stage 19.06 < .001 .254
Control 36 3.72 (3.04) 5.64 (3.59) 6.24 (3.75) Group 2.26 .139 .039
Interaction 0.48 .898 .002
 Phonological awareness: Sound Matching CTOPP-2 Intervention 22 4.09 (3.81) 5.45 (4.34) 5.41 (5.39) Stage 3.01 .053 .052
Control 35 3.66 (3.06) 4.03 (2.47) 4.63 (3.14) Group 1.18 .283 .021
Interaction 0.54 .587 .010
Phonological processing
 Phonological memory: Memory for Digits CTOPP-2 Intervention 22 10.50 (3.25) 11.55 (3.10) 11.68 (2.23) Stage 6.14 .003 .100
Control 35 11.23 (3.18) 11.77 (2.96) 12.14 (2.55) Group 0.45 .505 .008
Interaction 0.33 .723 .006
 Phonological memory: Nonword Repetition CTOPP-2 Intervention 22 2.86 (2.95) 4.32 (4.91) 4.36 (3.81) Stage 1.68 .192 .030
Control 35 2.71 (3.42) 4.37 (3.73) 3.31 (3.52) Group 0.88 .353 .016
Interaction 0.67 .514 .012
 Rapid nonsymbolic naming: Rapid Color Naming CTOPP-2 Intervention 15 59.47 (22.53) 52.73 (22.16) 56.00 (24.08) Stage 2.86 .065 .082
Control 19 57.63 (16.09) 51.79 (13.52) 53.58 (17.48) Group 0.09 .771 .003
Interaction 0.04 .961 .001
 Rapid nonsymbolic naming: Rapid Object Naming CTOPP-2 Intervention 16 64.44 (25.88) 62.06 (27.53) 65.94 (29.47) Stage 1.82 .168 .041
Control 29 62.28 (12.79) 60.52 (16.91) 64.72 (19.46) Group 0.07 .790 .002
Interaction 0.05 .827 .001
Children's participation and well-being
 Parent-reported communication outcomes FOCUS Intervention 11 246.6 (49.23) 261.9 (39.04) 253.9 (36.79) Stage 1.07 .355 .056
Control 9 261.4 (25.74) 267.9 (47.03) 261.9 (54.87) Group 0.31 .584 .017
Interaction 0.19 .827 .011
 Child-reported attitude score KiddyCAT Intervention 22 3.32 (2.15) 3.36 (2.26) 2.45 (2.35) Stage 2.93 .057 .047
Control 39 3.87 (2.45) 3.51 (2.86) 3.21 (2.40) Group 0.83 .367 .014
Interaction 0.42 .657 .007
 Child-reported happy Image Not Available occurrences SPAA-C Intervention 21 7.14 (2.74) 6.38 (2.46) 6.00 (2.85) Stage 2.09 .128 .037
Control 36 6.11 (3.04) 6.47 (2.49) 5.72 (2.53) Group 0.48 .493 .009
Interaction 1.09 .341 .019
Note. DEAP = Diagnostic Evaluation of Articulation and Phonology, Phonology Assessment; ICS = Intelligibility in Context Scale; PWPA = Preschool Word and Print Awareness; CTOPP-2 = Comprehensive Test of Phonological Processing–Second Edition; FOCUS = Focus on the Outcomes of Children Under Six; KiddyCAT = Communication Attitude Test for Preschool and Kindergarten Children Who Stutter; SPAA-C = Speech Participation and Activity Assessment of Children.
Note. DEAP = Diagnostic Evaluation of Articulation and Phonology, Phonology Assessment; ICS = Intelligibility in Context Scale; PWPA = Preschool Word and Print Awareness; CTOPP-2 = Comprehensive Test of Phonological Processing–Second Edition; FOCUS = Focus on the Outcomes of Children Under Six; KiddyCAT = Communication Attitude Test for Preschool and Kindergarten Children Who Stutter; SPAA-C = Speech Participation and Activity Assessment of Children.×
×
Speech-production instruments. The participants' speech production was assessed using four measures: the Phonology Assessment from the Diagnostic Evaluation of Articulation and Phonology (DEAP; Dodd, Hua, Crosbie, Holm, & Ozanne, 2002), phonological probes created by the research team, the Intelligibility in Context Scale (ICS; McLeod, Harrison, & McCormack, 2012a), and stimulability for each English consonant. The DEAP Phonology Assessment enables comprehensive sampling of a broad range of phonemes (consonants, vowels, and consonant clusters) in a range of contexts and syllable shapes, and provides normative data for Australian and British children. Each participant's responses to items on the DEAP were entered into Computerized Profiling (PROPH+; Long, Fey, & Channell, 2008). The percentage of consonants correct (PCC) was calculated by PROPH+ and was used as a main outcome measure. The research team developed phonological probes for each phonological pattern that could be treated using the teacher settings of PFSS (e.g., fronting, stopping). The majority of the probes consisted of 15 single words (range = 15–29) with an average of 19 opportunities to demonstrate each phonological error (range = 15–39). Each word was depicted by an illustration. Participants were asked to repeat the words after the SLP. The percentage of occurrence of the phonological pattern was calculated for each phonological probe. Intelligibility was assessed using the ICS, a parent-report scale of children's intelligibility in seven different contexts. The ICS has been validated and normed for use with Australian preschool children (McLeod et al., 2012b; McLeod, Crowe, & Shahaeian, 2015). Consonant stimulability was assessed by asking participants to produce consonants in isolation after a model from the SLP, with subsequent prompting if necessary. A score was generated for the number of stimulable consonants out of a possible total of 24.
Emergent-literacy instruments. Emergent literacy includes code-related skills (phonological awareness, print knowledge, and emergent writing) and oral-language skills (Whitehurst & Lonigan, 1998). For the purposes of this study, aspects of emergent literacy that could be affected by PFSS were assessed (i.e., phonological awareness and print knowledge). Emergent literacy was assessed using three measures: a letter-knowledge probe (developed from a task described by Anthony et al., 2011), the Preschool Word and Print Awareness measure (PWPA; Justice, Bowles, & Skibbe, 2006), and the Phonological-Awareness subtests within the Comprehensive Test of Phonological Processing–Second Edition (CTOPP-2; Wagner, Torgesen, Rashotte, & Pearson, 2013). Letter knowledge was determined by showing children pairs of each capital and lowercase letter of the alphabet in a random sequence. Children were asked to identify letters that they knew (e.g., Mm, Tt) and tell the SLP the name of the letter (e.g., em, tee) and the sound it made (e.g., /m/, /t/). The PWPA considers children's knowledge of books and text by sharing a picture book and asking questions (e.g., “Show me the first letter on this page”). A raw score out of a possible 17 was calculated, as was a print-concept knowledge estimate. Three subtests of the CTOPP-2 were administered and scored according to the published manual to consider participants' phonological awareness: Elision (removing phonological segments from spoken words to form other words), Blending Words (synthesizing sounds to form words), and Sound Matching (identifying words with the same initial and final sounds). The CTOPP-2 has been validated and normed in the United States on 1,900 children.
Phonological-processing instrument. Individual subtests from the CTOPP-2 were used to examine participants' phonological processing skills. Three subtests were used to measure phonological awareness (described previously)—Elision, Blending Words, and Sound Matching. Two subtests of phonological memory were used—Memory for Digits (repeating numbers accurately) and Nonword Repetition (repeating nonwords accurately). Two subtests of rapid nonsymbolic naming were used—Rapid Color Naming (rapidly naming colors) and Rapid Object Naming (rapidly naming objects).
Participation and well-being instruments. Children's participation and well-being was considered using four measures: the Focus on the Outcomes of Children Under Six (FOCUS; Thomas-Stonell et al., 2012), the Communication Attitude Test for Preschool and Kindergarten Children Who Stutter (KiddyCAT; Vanryckeghem & Brutten, 2006), the Speech Participation and Activity Assessment of Children (SPAA-C; McLeod, 2004), and the Australian Therapy Outcome Measures for Speech Pathology (AusTOMs; Perry & Skeat, 2004). The FOCUS enables measurement of changes in participants' participation in communicative contexts. The 50-item parent-report measure was used to consider participants' function (speech, expressive language, pragmatics, receptive language, and attention) and performance (intelligibility, expressive language, social play, independence, coping strategies, and emotions), and has been validated on 210 children in Canada (Thomas-Stonell, Oddson, Robertson, & Rosenbaum, 2010). The KiddyCAT was administered to investigate participants' perceptions of their speech ability and difficulties they had with talking. The KiddyCAT comprises 12 yes/no questions, including “Is talking hard for you?” and “Do you think that people need to help you talk?” The KiddyCAT has been standardized for children ages 3–6 years and has been used with a variety of clinical populations, including children with SSD (McLeod, Harrison, McAllister, & McCormack, 2013). Ten questions from the SPAA-C were administered to consider participants' feelings about talking in different communicative situations (e.g., “How do you feel when you talk to the whole class?”). Children were asked to color the face that best matched their response from the following options: Image Not AvailableImage Not AvailableImage Not Available ? O (another feeling). The total number of Image Not Available responses was added to calculate a score out of a possible total of 10. To date, the SPAA-C has not been normed or validated. The AusTOMs were completed by the SLP to describe participants' speech impairment, activity limitation, participation restriction, and distress on a 6-point scale ranging from 5 (no difficulty) to 0 (profound difficulty). Face and content validity of the AusTOMs have been established by Perry et al. (2004), and the interrater and test–retest reliability of the tool have been found to be “mostly satisfactory” (Morris et al., 2005, p. 344).
Intervention Instrument: PFSS
The original British version of PFSS (Wren & Roulstone, 2006) was adapted for Australia for use in the Sound Start Study (Wren & Roulstone, 2013). The four main adaptations were the use of four Australian speakers for the auditory stimuli (compared to one British speaker in the original version), the addition of cluster-reduction modules in the teacher settings, the replacement of culturally relevant pictures (e.g., lolly), and an increase in the number of word and nonword stimuli overall. Educators delivered PFSS using the teacher setting (rather than SLPs using the free configuration setting).
Trial Design
The Sound Start Study was a blinded cluster-randomized controlled trial in which children's progress with PFSS completed using preset teacher settings with early childhood educators was compared with the progress of a group of similar size who received typical classroom practices (i.e., whatever the child would typically receive). Early childhood education centers were randomized to receive one of the two types of service delivery. The allocation of participants within clusters (sites) provided protection from contamination across trial arms and increased the convenience of delivering the intervention within community settings.
The sites were divided and were allocated to one of two experienced SLPs (SLP1 and SLP2). These SLPs completed the preintervention assessments. Information about the number of children in each of their sites was sent to a statistician who randomized the sites into intervention and control conditions. The sites assessed by SLP1 were allocated to either intervention or control, and this was known only to SLP1; SLP2 remained unaware of preintervention assessment results and trial condition, and vice versa. Random allocation was performed on the sites, with all eligible children in a site allocated to the same trial condition (intervention or control). Children in the intervention arm received an individualized program that was based on their speech sound errors. Labels for intervention or control were assigned to each site on the basis of an unrestricted realization of a Bernoulli random variable (binomial distribution, with parameters π = .5, n = 1) using the random-number generator in SPSS (Version 20). This process ensured that each site had an equiprobable chance of being in the control or intervention arm. This process was independently performed for each SLP, with SLP2 unaware of the list generated for SLP1 and vice versa. There were no other restrictions imposed. The postintervention assessments were completed by four experienced SLPs (including SLP1 and SLP2). The SLPs were unaware of the intervention condition when they undertook the postintervention assessments (SLP1 and SLP2 did not reassess children from their allocated preintervention sites).
Procedure
Ethical approval was gained from Charles Sturt University (Approval 2013/070), the New South Wales Department of Education and Communities State Education Research Applications Process (Approval 2013267), and individual early childhood education centers as required. Consent was gained from the directors, teachers, and teaching assistants at the early childhood education centers and the participants' parents or caregivers, and assent was gained from the participants at each stage of the study.
Stage 1: Screening for Eligibility
The Sound Start Study was conducted in six stages (see Figure 1). During Stage 1 1,205 parents completed a two-page screening questionnaire containing questions about their children's speech, language, and general development. Teachers subsequently completed the same screening questionnaire for children whose parents consented to participate. Children who met inclusion criteria for Stage 2 (n = 323) were invited to participate in a direct assessment of their speech and language skills.
Stages 2 and 3: Direct Screening and Comprehensive Assessments
The parents of a total of 275 participants provided consent for participation in the direct-screening assessment phase of the study (see Table 1). Assessments were completed with one of two experienced SLPs in a quiet room at each participant's early childhood education center once assent had been obtained from the child. Stage 2 and Stage 3 assessments took approximately 30–60 min each, with breaks available for participants who required them. Video and/or audio recording was completed for tasks using a Panasonic HC-V700 video camera with an external Hahnel Mk100 unidirectional microphone and a Zoom H1 audio recorder. Online broad phonetic transcription of the DEAP was completed by the assessing SLP and later checked by the same SLP for accuracy using the audio recording. The AusTOMs measure was completed during, or immediately after, each assessment.
Parents were given a questionnaire to complete before each assessment stage and were asked to return the questionnaire to their early childhood education center. After administration of the DEAP in Stage 2, a member of the research team (the second author) determined which phonological probes should be administered in Stage 3 to every participant on the basis of their patterns of errors on the DEAP. For example, if a participant produced /s/ as [t] and /f/ as [p], then the stopping probe was selected. Participants' results on the probes were then used by the second author to determine the primary and secondary PFSS teacher settings to be used in the intervention phase. Primary and secondary intervention goals corresponding to a PFSS teacher setting were allocated to each participant who was eligible for Stage 4 (intervention and control) before allocation of the participants' conditions.
Stage 4: Intervention
Random allocation was performed for each early childhood education center (site). The educators were asked to oversee the PFSS intervention delivered via computer four times per week for 9 weeks (18 hr) in one-on-one sessions at the site. The educators were nominated by the center director on the basis of their willingness to participate. No formal education was required for the educators to facilitate the completion of the intervention. Sites were offered financial reimbursement to partially compensate for the time spent by the educators during this research and to maintain staff-to-student ratios in their centers.
Intervention was individualized for each child using the preset teacher settings in PFSS according to the identified phonological error patterns present during preintervention assessment (Stage 2). The allocation of 18 hr of intervention with PFSS was considered appropriate with respect to the intervention literature (Baker, 2012; Williams, 2012) and feasible within a 10-week preschool term, because PFSS could be provided over the first 9 weeks of the term (4 × 30 min./week or 2 × 60 min./week), allowing the 10th week to conduct an immediate posttreatment evaluation. The participants and educators wore headphones to listen to the PFSS program. The activities in PFSS required the participants to listen to and look at stimuli and respond in various ways using the computer mouse. When participants were not proficient at using the mouse, the educators moved it to the location on the screen indicated by the participants' pointing.
The first intervention session was overseen by the SLP who undertook the Stage 1–3 assessments to standardize delivery and solve any technical difficulties that arose. The same SLP monitored and video-recorded intervention in Weeks 2, 3, and 7–9 to ensure fidelity. The educators recorded the number of sessions completed (on paper). In addition, the PFSS program recorded the total number of games, total number of plays, total time spent on each game, and score achieved (out of 10) for each game. Children in both conditions were allowed to attend additional speech-language pathology services if organized by their parents or educators, and known attendance is noted in Figure 1.
Standard care consisted of typical classroom practice. All sites were asked to document their typical daily activities in a center questionnaire.
Stages 5 and 6: Immediate and Long-Term Follow-Up Assessments
The same two experienced SLPs (SLP1 and SLP2) conducted most of the immediate and long-term follow-up assessments postintervention at Stage 5 (n = 89, 78.8%) and Stage 6 (n = 102, 89.5%), with two other experienced SLPs completing a small proportion of the assessments in Stage 5 (n = 24, 21.2%) and Stage 6 (n = 12, 10.5%) in the final year of data collection. All SLPs were unaware of the information about the preintervention assessments (Stages 1–3) and trial arm (Stage 4) for the participants they assessed during Stages 5 and 6. The postintervention assessments followed a similar protocol to the preintervention assessments in that they took place in a quiet room in the early childhood education centers that the participants attended, with the consent of parents and the assent of child participants. The assessments took approximately 60 min. to complete. All assessment sessions were video- and audio-recorded. Broad transcription of the DEAP was completed online where possible and checked using the video and audio recordings.
Reliability
Inter- and intrajudge point-by-point reliability was completed for the DEAP Phonology Assessment on the basis of a randomly selected sample of 30 (10.9% of 275 participants) speech samples comprising 6,629 data points. Intrajudge agreement for broad phonetic transcription was 91.5%, and interjudge agreement was 90.1%. The reported level of reliability reflects “acceptable agreement,” because it was > 85% (Shriberg & Lof, 1991, p. 255).
Intervention Fidelity
Fidelity checking was based on video samples that included at least one full PFSS game (up to 10 min. of recorded video) for 32% of the participants (n = 20) in the intervention group during a session at the early childhood education center with the educator. A checklist was developed to determine whether the experimental tasks were completed as described. An independent observer viewed 20 videos of participants completing the intervention. On the basis of 264 data points, procedural fidelity for the experimental tasks was 95.5% (for further information about fidelity, see McCormack et al., 2017).
Data Analysis
Randomization of Clusters (Sites)
Prior reasoning on the design suggested that on average three participants be allocated per cluster (early childhood education center/site). The intracluster correlation coefficient was conservatively estimated to be .1, hence with a conservative design effect of 1.2. A design effect of 1.2 indicates that a 20% sample-size inflation is needed to maintain prespecified power after accounting for cluster effects. In the study, a total of 19 participating sites were randomized to the intervention arm, with a mean of 3.42 participants/cluster. A total of 20 participating sites were randomized to the control arm, with a mean of 2.90 participants/cluster. The intraclass correlation coefficient for the primary outcome variable was .11 (95% confidence interval [.04, .289]), consistent with prior expectations. For the sample data, an analysis using individual-level analyses produces the same broad conclusions as cluster-level analyses weighted by cluster size; for brevity, the individual-level analyses are presented in the Results section.
Analysis of Outcome Variables
The randomized controlled trial comprised two randomized groups (intervention, control) with data collection at three time points (Stages 2/3, Stage 5, Stage 6) with PCC as a single primary outcome variable. This design is readily amenable to analysis using analysis of variance (ANOVA) for a 2 × 3 within-subject and between-subjects mixed design, with randomized group as a two-level between-subjects factor (Group) and data-collection stage as a three-level repeated measures factor (Stage). This approach permits a statistical examination of the main effect of Group (i.e., whether mean values averaged across the three data-collection points differ between groups), the main effect of Stage (i.e., whether the mean values differ between the three stages irrespective of group assignment), and the two-way Group × Stage interaction (i.e., whether mean changes are group dependent). Between-groups comparisons at each stage were undertaken using the independent-samples t test, and within-group comparisons between stages were performed using the paired-samples t test.
The effect of the two-way Group × Stage interaction for the primary outcome variable was the most important contrast for the design. For correlated measures (r ≥ .6), a minimum sample size of n = 46 per group was needed for an interaction, corresponding to a medium effect size with 80% power in a design without clustering. For a clustered design, with a design effect of 1.2 the required minimum sample size rose to n = 56 per group. To account for 10% missing values, the sample size was upwardly revised to n = 63 per group.
In all analyses, the effect size was quantified using partial eta squared (ηp2). In two-way and higher order ANOVAs, this statistic indicates the proportion of variation attributable to a factor relative to the total of the error and factor variation, and it therefore always lies between 0 and 1. Thresholds for ηp2 are .01, .06, and .14 for small, medium, and large effects, respectively (Miles & Shevlin, 2001). The chi-square test of association was used to examine differences between groups for categorical data.
A missing-values analysis indicated that only 2.2% of outcome data were missing at Stage 2 or Stage 3 among those eligible for randomization. This percentage of missing data rose to 8.9% at Stage 5 but included 5.1% of randomized participants with data known to be missing completely at random (e.g., missing due to illness or away at time of assessment) and otherwise missing with no systematic pattern. The overall percentage of missing data at Stage 6 was similarly 8.9%, including 5.1% with data known to be missing completely at random (e.g., due to illness, or absence at time of evaluation). Analysis under multiple imputation does not affect the conclusions drawn for this data set, and for this reason the data are reported without imputation.
Results
An intention-to-treat analysis was carried out on the primary outcome measure (PCC) and the secondary outcome measures, followed by an analysis per protocol to account for the variation (with respect to intensity of PFSS in the intervention group) and receipt of additional SLP intervention received by each group.
Effectiveness of PFSS: Intention to Treat
The 123 participants who were eligible for intervention in Stage 4 of the Sound Start Study were randomized into two groups. There were 65 participants randomized to the intervention group and 58 to the control group; however, three participants withdrew from the study (parents of two participants withdrew consent, and one child did not provide assent to participate in intervention). There were thus 63 children (19 sites) in the intervention arm and 57 children (20 sites) in the control group (see Figure 1) whose results are reported. The two groups were similar on most measures but differed on severity of speech, as well as on age—by 1 month on average (see Table 2). For PCC on the DEAP, the descriptive statistics suggest a higher average in those who were subsequently randomized to intervention. However, the standard deviation is also larger in the control group, and these differences in the means and standard deviations are largely attributable to a single relatively low-value but genuine outlier in the control group at Stage 2 (consequently depressing the mean and raising the standard deviation in this group).
Speech-Production Accuracy
Three speech-production accuracy measures were collected once before intervention (at either Stage 2 or Stage 3) and twice after intervention (Stages 5 and 6).
PCC on the DEAP. Analysis using an ANOVA for a 2 × 3 mixed design indicated a statistically significant change in mean PCC on the Phonology Assessment of the DEAP between the data-collection stages (p < .001, ηp2 = .287) and a statistically significant average difference between the two groups (p = .009, ηp2 = .062). The Stage × Group interaction did not have a significant effect (p < .874, ηp2 = .001; see Table 3). In the intervention group there was a significant increase between Stage 2 and Stage 5 (p < .001), and this effect was maintained at Stage 6 (p = .458). This same pattern is observed in the control group, with a significant increase between Stage 2 and Stage 5 (p < .001), and this effect was maintained at Stage 6 (p = .078). When the mean DEAP PCC was adjusted for baseline levels at Stage 2, at Stage 6 it did not significantly differ between groups (p = .368, ηp2 = .007).
Primary intervention target: Phonological probes. Analysis of the data using an ANOVA for a 2 × 3 mixed design indicated statistically significant changes between the stages (p < .001, ηp2 = .319) but no average significant difference between the two groups (p = .322, ηp2 = .009), nor was there a statistically significant Stage × Group interaction (p < .329, ηp2 = .011; see Table 3). For the intervention group, the mean change between Stage 3 and Stage 5 was statistically significant (p < .001), as was the mean change between Stage 3 and Stage 6 (p < .001), but the mean change between Stage 5 and Stage 6 was not statistically significant (p = .161). The mean change in the control group between Stage 3 and Stage 5 was statistically significant (p < .001), as were the mean change between Stage 3 and Stage 6 (p < .001) and the mean change between Stage 5 and Stage 6 (p = .005).
ICS. The mean score on the ICS was calculated for the participants whose parents provided data for all seven items on the scale. Analysis using ANOVA for a 2 × 3 mixed design indicated a statistically significant change between stages (p = .019, ηp2 = .094) but no significant difference between groups (p = .365, ηp2 = .021). In addition, the Stage × Group interaction did not have a statistically significant effect (p = .726, ηp2 = .008; see Table 3). In the intervention group there was a significant change between Stage 2 and Stage 5 (p = .003) and between Stage 2 and Stage 6 (p = .006), but no significant change between Stage 5 and Stage 6. In the control group there was a similar significant change between Stage 5 and Stage 6 (p = .009), but the effect was less clear when considering Stage 2 against Stage 6 (p = .074).
Emergent-Literacy Skills
Three emergent-literacy measures were collected once before intervention (Stage 3) and at least once postintervention (Stage 5 and/or Stage 6) to consider outcomes over time.
Letter knowledge. Letter-knowledge data were collected once preintervention (Stage 3) and twice postintervention (Stages 5 and 6). Analysis using an ANOVA for a 2 × 3 mixed design indicated significant changes over time (p < .001, ηp2 = .186), but the main effect for randomized groups was not statistically significant (p = 0.110, ηp2 = .030), and changes between stages were not group dependent (p = .190, ηp2 = .020). In the intervention group, mean values for letter knowledge significantly increased between Stage 3 and Stage 5 (p < .001), between Stage 3 and Stage 6 (p < .001), and between Stage 5 and Stage 6 (p = .030). In the control group, mean values for letter knowledge significantly increased between Stage 3 and Stage 6 (p = .001) and between Stage 5 and Stage 6 (p = .022), but the effect between Stage 3 and Stage 5 was not significant (p = .129).
PWPA. PWPA data were collected for Stages 3 and 5, and the data were analyzed using ANOVA for a 2 × 2 mixed design. Mean PWPA significantly increased between the two stages (p < .001, ηp2 = .368), but there was no main effect attributable to randomized group (p = .858, ηp2 < .001), and changes over time were not group dependent (p = .053, ηp2 = .035).
Phonological awareness. Phonological-awareness data were collected once preintervention (Stage 3) and twice postintervention (Stages 5 and 6). Statistically significant changes occurred between stages in Elision (p < .001, ηp2 = .172) and Blending Words (p < .001, ηp2 = .181), but not in Sound Matching (p = .249, ηp2 = .014). Over the three stages, the two randomized groups did not significantly differ on Elision (p = .238, ηp2 = .014), Blending Words (p = .837, ηp2 < .001), or Sound Matching (p = .573, ηp2 = .003), and any mean changes over time were not group dependent for Elision (p = .208, ηp2 = .016), Blending Words (p = .509, ηp2 = .007), or Sound Matching (p = .518, ηp2 = .007).
Phonological-Processing Skills
Four phonological-processing measures were collected once before intervention (Stage 3) and twice postintervention (Stages 5 and 6).
Memory for Digits, Nonword Repetition, Rapid Color Naming, and Rapid Object Naming.Table 3 displays statistically significant increases between stages on Memory for Digits (p < .001, ηp2 = .077), Nonword Repetition (p = .004, ηp2 = .057), and Rapid Color Naming (p = .035, ηp2 = .060). However, these changes were not group dependent (respectively: p = .624, ηp2 = .005; p = .727, ηp2 = .003; p = .567, ηp2 = .010).
Children's Participation and Well-Being
Four participation and well-being measures were collected once before intervention (Stage 3) and twice postintervention (Stages 5 and 6).
FOCUS. The FOCUS total score was calculated for each participant. Analysis using an ANOVA for a 2 × 3 mixed design indicated that there were no significant changes attributable to stage (p = .167, ηp2 = .042), group (p = .606, ηp2 = .006), or the Stage × Group interaction (p = .668, ηp2 = .010; see Table 3). A post hoc analysis of means indicated that the two groups did not significantly differ in mean FOCUS total score at any stage. Mean values for the FOCUS total score did not significantly change between stages for the intervention or control group.
KiddyCAT. Analysis using an ANOVA for a 2 × 3 mixed design indicated a statistically significant effect for stage (p < .001, ηp2 = .073) but no significant effects for group (p = .267, ηp2 = .012) or the Group × Stage interaction (p = .292, ηp2 = .012). In the intervention group, there was a statistically significant difference between Stage 5 and Stage 6 (p = .005, two-sided) and between Stage 3 and Stage 6 (p < .001, two-sided), but no significant change between Stage 3 and Stage 5 (p = .123, two-sided). In the control group, the observed changes between Stage 3 and Stage 5, Stage 3 and Stage 6, and Stage 5 and Stage 6 did not achieve statistical significance.
SPAA-C. The number of times participants circled happy Image Not Available on the 10 items from the SPAA-C was determined for each stage. Analysis using an ANOVA for a 2 × 3 mixed design indicated that the main effect of stage was not statistically significant (p = .200, ηp2 = .016), nor was the main effect of randomized group (p = .080, ηp2 = .030). The Group × Stage interaction term, similarly, did not achieve statistical significance (p = .151, ηp2 = .018; see Table 3).
AusTOMs. The 5-point AusTOMs scales regarding Speech Impairment, Speech Activity, Speech Participation, and Speech Distress were completed by the assessing SLP and analyzed using Pearson's chi-square statistic. Significant differences were found between the randomized groups for Stage 2 and Stage 5 on the Speech Activity and Speech Participation scales, but not for any other scale or any other time. To be specific, Speech Impairment did not significantly differ between the randomized groups at Stage 2 (p = .480), Stage 5 (p = .601), or Stage 6 (p = .253). Speech Activity did not significantly differ between the two groups at Stage 2 (p = .716) or Stage 6 (p = .122), but there was a significant difference at Stage 5 (p = .048). Speech Participation did not significantly differ between the two groups at Stage 2 (p = .212) or Stage 6 (p = .314), but there was a statistically significant difference at Stage 5 (p = .040). Speech Distress did not significantly differ between randomized groups at Stage 2 (p = .763), Stage 5 (p = .921), or Stage 6 (p = .069).
Typical Classroom Practices
Of the 45 participating sites, directors of 44 completed and returned questionnaires (valid percentages reported) reporting their typical classroom practices. None of the sites employed an SLP or had an SLP who visited to provide assessment or intervention for participants.
Emergent-Literacy Instruction
Children were exposed “very much” or “quite a lot” to letter name/sound activities at 18 sites (40.9%) and sound-play activities at 19 sites (43.2%). Fifteen (34.1%) sites reported that they used a specific phonological-awareness program. Only one site (2.3%) reported not having letter name/sound or sound-play activities at all. When asked about technology, the directors of 34 centers (77.3%) reported that they felt children learned literacy through use of computers.
Daily Activities and Technology Use
Directors reported that the following activities happened “very much” at their centers: sitting and playing (n = 32, 72.7%), singing/stories/books (n = 20, 45.5%), individual attention in routines (n = 3, 6.8%), teaching good health practices (n = 15, 34.1%), active outdoor play (n = 25, 56.8%), and engaging in pretend play (n = 22, 50.0%). The daily activities and use of technology at each center varied, with 20 sites (45.5%) reporting daily computer use and 10 (22.7%) reporting computer use a few times a week. Directors reported varied access to computers, with 13 sites reporting that they do not have any computers dedicated for children's use and the remaining sites having a mean of 3.29 (range = 1–12) such computers. The use of technology at the sites was also varied. Some sites reported frequent child-directed access to technology on “most days” or “every day”: Four (9.1%) reported frequent child-led demonstrations of technology, 11 (25%) reported frequent child–adult interaction with technology, 15 (34.1%) reported frequent group technology activities, and 17 (38.6%) reported frequent independent computer use by the children at their center. The directors of 34 centers (77.3%) indicated that they “agree” or “strongly agree” that computers are an essential part of learning, and 41 (93.2%) indicated that they “agree” or “strongly agree” that it is good to use technology to build on children's interests. Fourteen (31.8%) directors saw facilitating Internet access as a priority for the children at their center.
Adherence to Intervention Protocol
Each participant in the intervention arm was requested to work on the PFSS software over 9 weeks for at least four sessions per week (sessions were approximately 30 min. each, indicating a total of approximately 18 hr of intervention, equivalent to 128–156 separate games). Over the trials, 39 of 63 (61.9%) intervention participants received at least 70% of the intended intervention intensity. This adherence level of 70% was considered acceptable, given that few studies have reported adherence levels better than 80% and that “positive results have often been obtained with levels around 60%” (Durlak & DuPre, 2008, p. 331).
Parents of participants in the intervention and control groups were asked to indicate whether their children received speech-language pathology intervention during the Sound Start Study. In the intervention group, 29 did not receive additional intervention, 24 did, and 10 parents did not respond. In the control group, 30 did not receive additional intervention, 10 did, and 17 parents did not respond.
Considering the adherence to protocol and participants' additional speech-language pathology intervention, there were a total of 23 participants who received an acceptable dosage of PFSS and no known additional intervention from an SLP (these participants were subsequently identified as receiving PFSS per protocol: “true PFSS”) and 47 in the control group who received no known additional intervention from an SLP (these participants were subsequently identified as the “true control” group). The effectiveness of PFSS was therefore also considered using a per-protocol analysis for the 23 participants who received true PFSS and the 47 participants in the true control group.
Effectiveness of PFSS: Per Protocol
Table 4 summarizes means, standard deviations, and statistical significance for the per-protocol analyses.
Speech-Production Accuracy
PCC on the DEAP. DEAP data for the true controls and true PFSS groups are summarized in Table 4. Analysis using an ANOVA for a 2 × 3 mixed design for these data gives the same statistical conclusions as the randomized-groups analysis—that is, statistically significant differences in mean PCC on the Phonology Assessment of the DEAP between the stages (p < .001, ηp2 = .324) and between the two groups (p = .003, ηp2 = .135), but a nonsignificant effect for the Stage × Group interaction (p = .916, ηp2 = .001).
Primary intervention target: Phonological probes. Analysis of the per-protocol subset indicates a statistically significant change in means between the stages (p < .001, ηp2 = .283) but no average significant difference between the two groups (p = .286, ηp2 = .019), and any changes in means were not group dependent (p = .614, ηp2 = .008; see Table 4).
ICS. In the per-protocol analysis, average mean ICS did not significantly differ between the two groups (p = .372, ηp2 = .047) or the three stages (p = .243, ηp2 = .008), and differences between groups did not significantly change between the stages (p = .996, ηp2 < .001).
Emergent-Literacy Skills
Three emergent-literacy measures were collected once before intervention (Stage 3) and at least once postintervention (Stage 5 and/or Stage 6) to consider outcomes over time (see Table 4), as noted in the intention-to-treat analysis.
Letter knowledge. For the per-protocol analysis, there were statistically significant changes in mean letter knowledge between stages (p < .001, ηp2 = .206), but the difference in means between groups did not significantly differ between stages (p = .371, ηp2 = .019). The two groups differed significantly at Stage 3 (p = .043), but not at Stage 5 (p = .128, ηp2 = .041) or Stage 6 (p = .440, ηp2 = .011) after controlling for initial differences at Stage 3.
PWPA. Mean PWPA significantly increased between Stage 3 and Stage 5 (p = .001, ηp2 = .159), but the per-protocol groups did not significantly differ on average (p = .483, ηp2 = .008), and changes over time were not group dependent (p = .198, ηp2 = .027).
Phonological awareness.Table 4 reports statistically significant changes between stages for Elision (p < .001, ηp2 = .216) and Blending Words (p < .001, ηp2 = .254) but not for Sound Matching (p = .053, ηp2 = .052). On average, the two per-protocol groups did not significantly differ on Elision (p = .241, ηp2 = .025), Blending Words (p = .139, ηp2 = .039), or Sound Matching (p = .283, ηp2 = .021). The extent of the mean difference between the two per-protocol groups did not significantly change between stages for Elision (p = .127, ηp2 = .037), Blending Words (p = .898, ηp2 = .002), or Sound Matching (p = .587, ηp2 = .010).
Phonological-Processing Skills
Four phonological-processing measures were collected once before intervention (Stage 3) and twice postintervention (Stages 5 and 6; see Table 4).
Memory for Digits, Nonword Repetition, Rapid Color Naming, and Rapid Object Naming. Mean Memory for Digits significantly increased over the three stages (p = .003, ηp2 = .100), as shown in Table 4. However, mean changes between the stages were not significant for Nonword Repetition (p = .192, ηp2 = .030), Rapid Color Naming (p = .065, ηp2 = .082), or Rapid Object Naming (p = .168, ηp2 = .041). On average, the two groups did not significantly differ on any of these four measures, and the extent of between-groups difference was not stage dependent for Memory for Digits (p = .723, ηp2 = .006), Nonword Repetition (p = .514, ηp2 = .012), Rapid Color Naming (p = .961, ηp2 = .001), or Rapid Object Naming (p = .827, ηp2 = .001).
Children's Participation and Well-Being
Three participation and well-being measures were collected once before intervention (Stage 3) and twice postintervention (Stage 5 and Stage 6; see Table 4). On average, the per-protocol groups did not significantly differ on mean FOCUS (p = .584, ηp2 = .017), mean KiddyCAT (p = .367, ηp2 = .014), or mean SPAA-C (p = .493, ηp2 = .009). Mean KiddyCAT significantly decreased between stages (p < .001, ηp2 = .073), as shown in Table 4, but the main effect of stage did not achieve statistical significance for FOCUS (p = .355, ηp2 = .056) or SPAA-C (p = .128, ηp2 = .037). In addition, the extent of differences between groups did not significantly change between the stages for FOCUS (p = .827, ηp2 = .011), KiddyCAT (p = .292, ηp2 = .012), or SPAA-C (p = .341, ηp2 = .019).
Discussion
The aim of this study was to determine whether early childhood educators using the teacher settings in PFSS—a computer-based intervention targeting speech-input processing and phonological awareness—could improve the speech production, emergent literacy, phonological processing, participation, and well-being of Australian preschoolers with SSD. The experimental design was robust. Contrary to our predictions, PFSS (delivered by educators using the PFSS teacher setting) did not result in greater gains than typical classroom practice in this study. Rather, the participants in both groups showed a statistically significant improvement on most but not all measures of speech production, emergent literacy, and phonological processing from pre- to postintervention. Most measures of well-being were not significant over time or between groups. These results were similar for the intention-to-treat data and per-protocol data (i.e., the subgroup of 61.9% of participants in the intervention group who received an acceptable dosage of PFSS and those in the intervention and control groups who did not receive any additional speech-language pathology intervention over the course of the study). The findings raise a number issues for discussion, including the meaning of statistical, clinical, and personal significance, why participants in the intervention group (who received PFSS delivered by educators using the teacher settings) did not show greater improvement than participants in the control group, and what could be done to address the gap between the demand and supply of speech-language pathology services for children with SSD.
Separating Statistical Significance From Clinical and Personal Significance
The statistical analyses revealed significant improvements in measures of speech production, emergent literacy, and some measures of phonological processing, participation, and well-being for participants in the intervention and control groups. Although this was encouraging, closer inspection of the measures suggested that the average improvement was not clinically significant, because difficulties in speech, emergent literacy, and phonological processing were still apparent postintervention. For example, the severity of the participants' SSD in the intervention group remained mild–moderate (on the basis of PCC) despite intervention. According to Bothe and Richardson (2011), clinical significance is only apparent when a change is sufficient to modify a clinical description or label for a presenting problem. The lack of clinical significance is also apparent when the degree of change is considered. For example, the average percentage improvement in PCC from the DEAP Phonology Assessment for the participants in both groups from pre- to immediate postintervention was approximately 6%. Given that preassessment occurred in Stage 2 (6–8 weeks before starting intervention), intervention was 9 weeks in duration, and postassessment occurred 1 week later, this degree of improvement occurred over approximately 16 weeks. In a study comparing the effect of minimal- versus nonminimal-contrast intervention delivered weekly by SLPs in 30-min. sessions for 12 weeks, Dodd et al. (2008)  reported that their participants' increase in PCC (using the same assessment task as the current study) was over 16%. This degree of improvement was commensurate with other studies of phonological intervention (e.g., Crosbie, Holm, & Dodd, 2005).
Measures assessing the personal experience (i.e., SPAA-C) and the impact of SSD on day-to-day life (i.e., FOCUS) suggest that the statistically significant change was not personally significant. Personal significance is only apparent when individuals report improvements that matter to them—improvements that change the way they function in day-to-day life (Bothe & Richardson, 2011). The findings from this study highlight the importance of collecting measures of impairment (e.g., PCC, percent occurrence of a phonological process) in addition to personal measures of participation and wellness when interpreting the effect of intervention on children with SSD and their families.
Why Did the Intervention Not Work?
PFSS was designed for children with phonologically based SSD. In the current study, the delivery of PFSS by educators in early childhood education centers did not result in significantly better speech, emergent literacy, phonological processing, or participation and well-being for the children in the intervention group compared to the control group. We see five possible reasons for this.
First, in the current study PFSS was delivered by educators using the teacher settings rather than the free configuration setting, as was used by Wren and Roulstone (2008) . We chose to use the teacher settings because it simplified the delivery of the intervention and addressed one of the primary aims of this study: to investigate the delivery of intervention by non-SLP intervention agents. It meant that the educators did not need to assess and monitor children's speech; they needed to facilitate a child's completion of activities in PFSS. However, in doing so, it is possible that the teacher settings diminished opportunities to dynamically tailor PFSS to the children's responses—selecting easier or more challenging games and/or selecting different error patterns to facilitate the children's progress from session to session.
Second, although the effectiveness of the teacher settings themselves is unknown, an alternative explanation is that delivery of intervention for children with SSD from non-SLPs is ineffective when SLP involvement is reduced to advising about targets and providing a program. As Dodd and Barker (1990)  have reported, it may be that educators have too many barriers in their workplace setting to implement intervention for children with SSD. Many studies have included support from parents as a key element of the intervention program (Bowen & Cupples, 1999), and parents can be trained to be effective intervention agents (Sugden, Baker, Munro, & Williams, 2016), although meta-analyses of the effects of parent interventions suggest that implementation of this is by no means straightforward (Law et al., 2003). The possibility that PFSS may be effective when well implemented by parents using the teacher or free configuration setting remains to be determined.
Third, not all participants in the intervention group received the proposed intervention intensity—39 of the 63 participants (61.9%) in the intervention group received at least 70% of the intended intervention. It is possible that underdosing moderated the effect of PFSS. In follow-up investigations of the current study, the educators were interviewed about their experience implementing PFSS in an early childhood education setting (Crowe et al., in press), and comparisons were made regarding the intensity of the intervention as recorded by the educators and the computer (McCormack et al., 2017). As part of these investigations, multiple barriers and facilitators to implementation were identified, including personal factors (e.g., child engagement with PFSS), environmental factors (e.g., the logistics of implementing PFSS during a busy preschool day), and computer-program factors (e.g., program format, varied game durations). As in the study by Dodd and Barker (1990), the educators found it challenging to consistently find the time to conduct the prescribed number of games each week with the participant(s) at their center. If we are to find a solution to the gap between the demand and supply for speech-language pathology services, PFSS implemented by educators using the teacher setting does not appear to be a viable option. Alternative or supplementary solutions need to be found. Perhaps PFSS could be effective, but only when an optimal intensity of practice is adhered to and the program is implemented at an acceptable level across intervention agents and settings (e.g., SLP, parent, educator, therapy assistant). Exactly what constitutes an acceptable level of implementation and what would be needed to ensure this level in day-to-day contexts remains to be determined. As Durlak (2015)  points out, more research about implementation adherence is needed if we are to determine the conditions under which interventions are and are not effective.
Fourth, it is possible that some children did not have input-based problems underlying their surface-level SSD, or that input-processing problems were having less impact on their SSD than output factors. Although individuals were assessed on the CTOPP-2, a measure of phonological processing, the results are presented for the groups; it is possible that analysis at the individual level may reveal that children with poorer performance on phonological-processing measures prior to intervention made more progress with the intervention than those who showed better performance. In contrast, those with a predominantly output-processing basis to their SSD would have benefited from a different approach to intervention.
As a final possible explanation, it is important to consider the possibility that PFSS is not effective in changing speech output or in teaching phonological awareness in children with phonologically based SSD. There is not enough space to discuss whether this would be the tool itself or the theoretical approach to intervention that underpins it, but it is nevertheless difficult to know whether either is the case, because other factors (e.g., use of the teacher setting, the suboptimal intervention intensity) may have masked the possible effect of PFSS on the children's speech, emergent literacy, phonological processing, and participation and well-being. It is also possible that PFSS works for some but not all children with phonologically based SSD, given the range in the amount of change in PCC from pre- to immediate postintervention (−12.6% to +35.36%) for the participants in the intervention group. However, it is also possible that other factors influenced the change in the participants' PCC from pre- to immediate postintervention, given the range in the amount of change (−12.5% to +29.10%) for participants in the control group. Receipt of additional speech-language pathology services is one possible factor, given that the participant in the intervention group who showed a change in PCC of 35.36% over approximately 16 weeks was reported to have received speech-language pathology intervention over the course of the study. This cannot be the sole factor influencing change, because the participant in the control group who showed a change in PCC of 29.1% over the course of the intervention was reported to have not received any additional speech-language pathology services over the course of the study. Further research is clearly needed to better understand the natural history of SSD in preschool children and the factors associated with children who show little versus considerable improvement in speech production, emergent literacy, phonological processing, and participation and well-being over time (Roulstone, Miller, Wren, & Peters, 2009).
Limitations
Although this study used a robust experimental design, it is not without limitations. First, a variety of outcome measures were used to assess the effect of PFSS. Measures of the children's speech focused on speech production; measures of speech perception were not included. It is therefore unknown if PFSS improved the quality of the children's acoustic-perceptual representations for speech. Second, PFSS was implemented by different educators from different early childhood education centers. Some educators implemented the program with multiple participants, whereas others implemented it with one participant. Given that the effect of the number of children per educator was not controlled for, varied experience with the program may have influenced the result. Given that individual SLPs have been reported to differentially contribute to gains in school-age children's language and literacy abilities (Farquharson, Tambyraja, Logan, Justice, & Schmitt, 2015), it is also possible that variation in early childhood educator characteristics (e.g., level of education, years of experience, age) influenced the results. Last, not all participants received the recommended intensity. This was a difficult variable to control for, given the real-world constraints and demands on day-to-day life in a busy preschool setting. Some educators worked consistently with the participants, achieving intensity compliance rates over 90%, but some did not adhere to the prescribed intensity (Crowe et al., in press; McCormack et al., 2017). This variation in intensity may have influenced the result. Nonetheless, a pragmatic trial is an important step in understanding how effective an intervention is likely to be in a real-world setting.
Future Directions: Closing the Gap Between the Demand and Supply of SLPs for Children With SSD
Preschool children with SSD have the potential to become intelligible speakers and competent readers and spellers during the school years (Gillon, 2005). Although some participants in the current study improved without intervention, others showed relatively little improvement over time. If we are to provide all preschool children with SSD the opportunity to become intelligible before or by the time that formal literacy instruction starts in the early school years and achieve literacy success, we need to identify and support those children who are less likely to improve without help. We also need to identify interventions suited to their needs. For some children this might be input-based interventions such as PFSS. Further research is needed to explore this possibility, controlling for the effects of intervention agent and intervention intensity. For some children, this intervention might involve cognitive–linguistic tasks coupled with production practice (e.g., Williams, 2012). For others, intervention might combine input and output (production) procedures (e.g., Hodson, 2007). Rvachew and Brosseau-Lapré (2015)  found that whatever approach is used by an SLP, follow-up activities completed by non-SLPs (e.g., parent, educator) need to be similar to what is completed by the SLP. For instance, they report that an SLP-delivered input-based intervention comprising at least 16 different treatment procedures, such as focused stimulation, chaining, delayed imitation, and receptive and expressive minimal pairs, was considered effective when paired with dialogic reading for home practice. It is important to note that even though their approach was identified as an input-based approach, it still included opportunities for production practice.
Across empirical evidence reporting effective interventions for children with SSD, most involve speech-production practice of carefully selected targets (with or without input-based procedures), implemented by an SLP through the use of a variety of instructional cues and feedback (Baker & McLeod, 2011; McLeod & Baker, 2017). If we are to move forward in closing the gap between supply and demand for intervention by using non-SLPs, the findings from the current study suggest that we need to focus our efforts on using effective interventions suited to children's needs, and adopt empirically supported training strategies that facilitate faithful implementation of those interventions.
Acknowledgments
This research was supported by the Australian Research Council Discovery Grant DP130102545 (awarded to S. McLeod, E. Baker, J. McCormack, Y. Wren, and S. Roulstone) and funding from the New South Wales Department of Education Grant (awarded to S. McLeod, Y. Wren, E. Baker, J. McCormack, K. Crowe, S. Masso, and S. Roulstone). The authors thank Felicity McKellar and the participating educators, parents, and children.
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Footnotes
1 Forty-seven sites agreed to participate, but two were excluded due to low return rate of Stage 1 questionnaires. One site did not return any questionnaires, and the other returned four (< 10% of its cohort) in which there were no concerns about children's communication.
Forty-seven sites agreed to participate, but two were excluded due to low return rate of Stage 1 questionnaires. One site did not return any questionnaires, and the other returned four (< 10% of its cohort) in which there were no concerns about children's communication.×
2 The eligibility criterion for nonverbal intelligence was adapted from Year 1 (Nonverbal Index Score > 79) to Year 2 (Nonverbal Index Score > 70).
The eligibility criterion for nonverbal intelligence was adapted from Year 1 (Nonverbal Index Score > 79) to Year 2 (Nonverbal Index Score > 70).×
Figure 1.

Participant recruitment and randomization flow diagram. SLP = speech-language pathologist.

 Participant recruitment and randomization flow diagram. SLP = speech-language pathologist.
Figure 1.

Participant recruitment and randomization flow diagram. SLP = speech-language pathologist.

×
Table 1. Eligibility criteria from Stages 1, 2, and 3 for inclusion in Stage 4 (intervention/control) of the Sound Start Study.
Eligibility criteria from Stages 1, 2, and 3 for inclusion in Stage 4 (intervention/control) of the Sound Start Study.×
Stage Skill Criteria Assessment tool Informant
1: Screening for eligibility by parents/teacher Speech Difficulty talking and making speech sounds (yes or a little concerned) Parents' Evaluation of Developmental Status (Glascoe, 2000) Parent and/or teacher
Speech Speech not clear to family and/or others Parent questionnaire a Parent and/or teacher
Medical and developmental history Reported no persistent hearing loss, cleft lip or palate, or developmental delay Parent questionnaire a Parent and/or teacher
English language use English language skills had to be equivalent to or better than their skills in the other language Parent questionnaire Parent
2: Assessment for eligibility following direct screening assessment by speech-language pathologist Speech Percentage of consonants correct standard score ≤ 6 (i.e., greater than 1 SD below the mean) Diagnostic Evaluation of Articulation and Phonology, Phonology Assessment (Dodd et al., 2002) Direct assessment
Had a phonological pattern that could be treated by PFSS
Nonverbal intelligence Year 1: Nonverbal Index Score > 79 (percentile rank of > 8); Years 2 and 3: Nonverbal Index Score > 70 (percentile rank of > 2). Primary Test of Nonverbal Intelligence (Ehrler & McGhee, 2008) Direct assessment
3: Assessment for eligibility following direct comprehensive assessment by speech-language pathologist Receptive vocabulary Receptive vocabulary score less than 2 SDs below the mean Peabody Picture Vocabulary Test–Fourth Edition (Dunn & Dunn, 2007) Direct assessment
Hearing Passed hearing screening of all frequencies at 40 dB during Stage 2 or Stage 3 Pure-tone audiometry (500, 1000, 2000, 4000 Hz) at 40 dB, adjusted for noisy environments (American Speech-Language-Hearing Association, 1985) Direct assessment
Note. PFSS = Phoneme Factory Sound Sorter.
Note. PFSS = Phoneme Factory Sound Sorter.×
a Question used with permission from Longitudinal Study of Australian Children (Australian Institute of Family Studies, 2007).
Question used with permission from Longitudinal Study of Australian Children (Australian Institute of Family Studies, 2007).×
Table 1. Eligibility criteria from Stages 1, 2, and 3 for inclusion in Stage 4 (intervention/control) of the Sound Start Study.
Eligibility criteria from Stages 1, 2, and 3 for inclusion in Stage 4 (intervention/control) of the Sound Start Study.×
Stage Skill Criteria Assessment tool Informant
1: Screening for eligibility by parents/teacher Speech Difficulty talking and making speech sounds (yes or a little concerned) Parents' Evaluation of Developmental Status (Glascoe, 2000) Parent and/or teacher
Speech Speech not clear to family and/or others Parent questionnaire a Parent and/or teacher
Medical and developmental history Reported no persistent hearing loss, cleft lip or palate, or developmental delay Parent questionnaire a Parent and/or teacher
English language use English language skills had to be equivalent to or better than their skills in the other language Parent questionnaire Parent
2: Assessment for eligibility following direct screening assessment by speech-language pathologist Speech Percentage of consonants correct standard score ≤ 6 (i.e., greater than 1 SD below the mean) Diagnostic Evaluation of Articulation and Phonology, Phonology Assessment (Dodd et al., 2002) Direct assessment
Had a phonological pattern that could be treated by PFSS
Nonverbal intelligence Year 1: Nonverbal Index Score > 79 (percentile rank of > 8); Years 2 and 3: Nonverbal Index Score > 70 (percentile rank of > 2). Primary Test of Nonverbal Intelligence (Ehrler & McGhee, 2008) Direct assessment
3: Assessment for eligibility following direct comprehensive assessment by speech-language pathologist Receptive vocabulary Receptive vocabulary score less than 2 SDs below the mean Peabody Picture Vocabulary Test–Fourth Edition (Dunn & Dunn, 2007) Direct assessment
Hearing Passed hearing screening of all frequencies at 40 dB during Stage 2 or Stage 3 Pure-tone audiometry (500, 1000, 2000, 4000 Hz) at 40 dB, adjusted for noisy environments (American Speech-Language-Hearing Association, 1985) Direct assessment
Note. PFSS = Phoneme Factory Sound Sorter.
Note. PFSS = Phoneme Factory Sound Sorter.×
a Question used with permission from Longitudinal Study of Australian Children (Australian Institute of Family Studies, 2007).
Question used with permission from Longitudinal Study of Australian Children (Australian Institute of Family Studies, 2007).×
×
Table 2. Characteristics of the intervention and control groups in the Sound Start Study (n = 123) prior to intervention.
Characteristics of the intervention and control groups in the Sound Start Study (n = 123) prior to intervention.×
Parameter Measure Valid n Intervention group Control group Significant difference (p)
Age, M (SD) Months 123 55.3 (4.1) 56.9 (4.3) .044
Sex, n (%) Male 79 43 (66.2) 36 (62.1) .637
Female 44 22 (33.8) 22 (37.9)
Multilingual status, n (%) English only 100 52 (80.0) 48 (82.8) .695
Multilingual 23 13 (20.0) 10 (17.2)
Socioeconomic status, M (SD) IRSAD 123 6.2 (2.9) 5.8 (3.5) .495
Speech severity, M (SD) DEAP percentage of consonants correct 123 68.15 (9.90) 63.19 (13.76) .022
Consonant stimulability, M (SD) Number of English consonants out of 24 123 22.3 (1.8) 22.0 (1.9) .338
Phonological awareness, M (SD) CTOPP-2 Phonological Awareness composite score 122 89.0 (11.5) 87.4 (10.4) .432
Nonverbal IQ, M (SD) PTONI raw score 123 22.4 (8.8) 22.0 (8.9) .788
Receptive vocabulary, M (SD) PPVT-4 raw score 123 68.1 (18.3) 71.5 (19.2) .309
Note. IRSAD = Index of Relative Socioeconomic Advantage and Disadvantage; DEAP = Diagnostic Evaluation of Articulation and Phonology; CTOPP-2 = Comprehensive Test of Phonological Processing–Second Edition; PTONI = Primary Test of Nonverbal Intelligence; PPVT-4 = Peabody Picture Vocabulary Test–Fourth Edition.
Note. IRSAD = Index of Relative Socioeconomic Advantage and Disadvantage; DEAP = Diagnostic Evaluation of Articulation and Phonology; CTOPP-2 = Comprehensive Test of Phonological Processing–Second Edition; PTONI = Primary Test of Nonverbal Intelligence; PPVT-4 = Peabody Picture Vocabulary Test–Fourth Edition.×
Table 2. Characteristics of the intervention and control groups in the Sound Start Study (n = 123) prior to intervention.
Characteristics of the intervention and control groups in the Sound Start Study (n = 123) prior to intervention.×
Parameter Measure Valid n Intervention group Control group Significant difference (p)
Age, M (SD) Months 123 55.3 (4.1) 56.9 (4.3) .044
Sex, n (%) Male 79 43 (66.2) 36 (62.1) .637
Female 44 22 (33.8) 22 (37.9)
Multilingual status, n (%) English only 100 52 (80.0) 48 (82.8) .695
Multilingual 23 13 (20.0) 10 (17.2)
Socioeconomic status, M (SD) IRSAD 123 6.2 (2.9) 5.8 (3.5) .495
Speech severity, M (SD) DEAP percentage of consonants correct 123 68.15 (9.90) 63.19 (13.76) .022
Consonant stimulability, M (SD) Number of English consonants out of 24 123 22.3 (1.8) 22.0 (1.9) .338
Phonological awareness, M (SD) CTOPP-2 Phonological Awareness composite score 122 89.0 (11.5) 87.4 (10.4) .432
Nonverbal IQ, M (SD) PTONI raw score 123 22.4 (8.8) 22.0 (8.9) .788
Receptive vocabulary, M (SD) PPVT-4 raw score 123 68.1 (18.3) 71.5 (19.2) .309
Note. IRSAD = Index of Relative Socioeconomic Advantage and Disadvantage; DEAP = Diagnostic Evaluation of Articulation and Phonology; CTOPP-2 = Comprehensive Test of Phonological Processing–Second Edition; PTONI = Primary Test of Nonverbal Intelligence; PPVT-4 = Peabody Picture Vocabulary Test–Fourth Edition.
Note. IRSAD = Index of Relative Socioeconomic Advantage and Disadvantage; DEAP = Diagnostic Evaluation of Articulation and Phonology; CTOPP-2 = Comprehensive Test of Phonological Processing–Second Edition; PTONI = Primary Test of Nonverbal Intelligence; PPVT-4 = Peabody Picture Vocabulary Test–Fourth Edition.×
×
Table 3. Outcomes of the intervention and control groups in the Sound Start Study: Intention to treat (complete cases).
Outcomes of the intervention and control groups in the Sound Start Study: Intention to treat (complete cases).×
Parameter Measure Group Valid n Stage 2/3, M (SD) Stage 5, M (SD) Stage 6, M (SD) Effect F p ηp 2
Speech production
 Percentage of consonants correct DEAP Intervention 59 69.25 (9.13) 75.40 (10.27) 76.06 (9.99) Stage 42.36 < .001 .287
Control 48 64.34 (11.74) 69.77 (12.97) 71.14 (12.78) Group 6.98 .009 .062
Interaction 0.14 .874 .001
 Primary intervention target: Probes Sound Start Study probes Intervention 59 71.27 (25.72) 47.14 (38.12) 43.28 (36.02) Stage 48.79 < .001 .319
Control 47 73.30 (28.35) 57.41 (36.49) 48.19 (36.22) Group 0.99 .322 .009
Interaction 1.12 .329 .011
 Intelligibility ICS Intervention 30 3.75 (0.36) 3.95 (0.39) 3.97 (0.45) Stage 4.14 .019 .094
Control 14 3.90 (0.38) 4.06 (0.48) 4.01 (0.28) Group 0.84 .365 .021
Interaction 0.32 .726 .008
Emergent literacy
 Letter knowledge Anthony et al. (2011)  Intervention 44 8.02 (8.58) 10.95 (9.41) 11.75 (9.40) Stage 19.18 < .001 .186
Control 42 5.95 (7.96) 6.90 (8.82) 9.02 (9.43) Group 2.61 .110 .030
Interaction 1.68 .190 .020
 Word and print awareness PWPA Intervention 59 6.24 (3.43) 7.59 (2.75) Stage 62.31 < .001 .368
Control 51 5.69 (3.09) 7.29 (3.16) Group 0.03 .858 .000
Interaction 3.84 .053 .035
 Phonological awareness: Elision CTOPP-2 Intervention 55 2.58 (4.36) 3.38 (3.83) 3.91 (4.11) Stage 19.99 < .001 .172
Control 43 3.02 (3.83) 4.19 (3.86) 5.37 (3.96) Group 1.41 .238 .014
Interaction 1.59 .208 .016
 Phonological awareness: Blending Words CTOPP-2 Intervention 55 4.09 (4.02) 5.33 (4.54) 6.07 (4.62) Stage 21.44 < .001 .181
Control 44 3.66 (3.14) 5.61 (3.40) 5.77 (3.87) Group 0.04 .837 .000
Interaction 0.68 .509 .007
 Phonological awareness: Sound Matching CTOPP-2 Intervention 56 3.88 (3.30) 4.45 (3.56) 5.77 (3.87) Stage 1.40 .249 .014
Control 43 4.09 (3.28) 3.93 (2.52) 4.33 (3.14) Group 0.32 .573 .003
Interaction 0.66 .518 .007
Phonological processing
 Phonological memory: Memory for Digits CTOPP-2 Intervention 55 10.44 (2.86) 11.33 (2.99) 11.60 (2.65) Stage 7.92 < .001 .077
Control 42 11.50 (3.19) 11.88 (3.62) 12.40 (2.58) Group 2.32 .131 .024
Interaction 0.47 .624 .005
 Phonological memory: Nonword Repetition CTOPP-2 Intervention 55 2.65 (2.78) 3.62 (3.75) 3.75 (3.64) Stage 5.81 .004 .057
Control 43 2.49 (3.31) 4.05 (3.63) 3.65 (3.41) Group 0.01 .914 .000
Interaction 0.01 .727 .003
 Rapid nonsymbolic naming: Rapid Color Naming CTOPP-2 Intervention 34 58.29 (18.86) 54.94 (20.13) 56.76 (21.95) Stage 3.47 .035 .060
Control 22 58.00 (15.58) 51.14 (12.88) 52.68 (16.35) Group 0.37 .548 .007
Interaction 0.57 .567 .010
 Rapid nonsymbolic naming: Rapid Object Naming CTOPP-2 Intervention 41 64.02 (19.77) 63.44 (21.20) 65.41 (23.44) Stage 0.96 .384 .013
Control 34 62.38 (12.61) 62.18 (17.49) 64.35 (18.82) Group 0.10 .749 .001
Interaction 0.02 .983 .000
Children’s participation and well-being
 Parent-reported communication outcomes FOCUS Intervention 29 253.4 (49.25) 256.8 (52.68) 261.1 (49.57) Stage 1.83 .167 .042
Control 15 256.5 (38.09) 269.2 (38.36) 267.5 (49.69) Group 0.27 .606 .006
Interaction 0.41 .668 .010
 Child-reported attitude score KiddyCAT Intervention 57 3.68 (2.42) 3.23 (2.61) 2.26 (2.39) Stage 7.99 < .001 .073
Control 46 3.76 (2.48) 3.61 (2.94) 3.15 (2.37) Group 1.25 .267 .012
Interaction 1.24 .292 .012
 Child-reported happy Image Not Available occurrences SPAA-C Intervention 56 6.95 (2.76) 6.41 (2.38) 5.90 (2.62) Stage 1.62 .200 .016
Control 44 5.60 (3.04) 5.87 (2.71) 5.64 (2.60) Group 3.13 .080 .030
Interaction 1.91 .151 .018
Note. DEAP = Diagnostic Evaluation of Articulation and Phonology, Phonology Assessment; ICS = Intelligibility in Context Scale; PWPA = Preschool Word and Print Awareness; CTOPP-2 = Comprehensive Test of Phonological Processing–Second Edition; FOCUS = Focus on the Outcomes of Children Under Six; KiddyCAT = Communication Attitude Test for Preschool and Kindergarten Children Who Stutter; SPAA-C = Speech Participation and Activity Assessment of Children.
Note. DEAP = Diagnostic Evaluation of Articulation and Phonology, Phonology Assessment; ICS = Intelligibility in Context Scale; PWPA = Preschool Word and Print Awareness; CTOPP-2 = Comprehensive Test of Phonological Processing–Second Edition; FOCUS = Focus on the Outcomes of Children Under Six; KiddyCAT = Communication Attitude Test for Preschool and Kindergarten Children Who Stutter; SPAA-C = Speech Participation and Activity Assessment of Children.×
Table 3. Outcomes of the intervention and control groups in the Sound Start Study: Intention to treat (complete cases).
Outcomes of the intervention and control groups in the Sound Start Study: Intention to treat (complete cases).×
Parameter Measure Group Valid n Stage 2/3, M (SD) Stage 5, M (SD) Stage 6, M (SD) Effect F p ηp 2
Speech production
 Percentage of consonants correct DEAP Intervention 59 69.25 (9.13) 75.40 (10.27) 76.06 (9.99) Stage 42.36 < .001 .287
Control 48 64.34 (11.74) 69.77 (12.97) 71.14 (12.78) Group 6.98 .009 .062
Interaction 0.14 .874 .001
 Primary intervention target: Probes Sound Start Study probes Intervention 59 71.27 (25.72) 47.14 (38.12) 43.28 (36.02) Stage 48.79 < .001 .319
Control 47 73.30 (28.35) 57.41 (36.49) 48.19 (36.22) Group 0.99 .322 .009
Interaction 1.12 .329 .011
 Intelligibility ICS Intervention 30 3.75 (0.36) 3.95 (0.39) 3.97 (0.45) Stage 4.14 .019 .094
Control 14 3.90 (0.38) 4.06 (0.48) 4.01 (0.28) Group 0.84 .365 .021
Interaction 0.32 .726 .008
Emergent literacy
 Letter knowledge Anthony et al. (2011)  Intervention 44 8.02 (8.58) 10.95 (9.41) 11.75 (9.40) Stage 19.18 < .001 .186
Control 42 5.95 (7.96) 6.90 (8.82) 9.02 (9.43) Group 2.61 .110 .030
Interaction 1.68 .190 .020
 Word and print awareness PWPA Intervention 59 6.24 (3.43) 7.59 (2.75) Stage 62.31 < .001 .368
Control 51 5.69 (3.09) 7.29 (3.16) Group 0.03 .858 .000
Interaction 3.84 .053 .035
 Phonological awareness: Elision CTOPP-2 Intervention 55 2.58 (4.36) 3.38 (3.83) 3.91 (4.11) Stage 19.99 < .001 .172
Control 43 3.02 (3.83) 4.19 (3.86) 5.37 (3.96) Group 1.41 .238 .014
Interaction 1.59 .208 .016
 Phonological awareness: Blending Words CTOPP-2 Intervention 55 4.09 (4.02) 5.33 (4.54) 6.07 (4.62) Stage 21.44 < .001 .181
Control 44 3.66 (3.14) 5.61 (3.40) 5.77 (3.87) Group 0.04 .837 .000
Interaction 0.68 .509 .007
 Phonological awareness: Sound Matching CTOPP-2 Intervention 56 3.88 (3.30) 4.45 (3.56) 5.77 (3.87) Stage 1.40 .249 .014
Control 43 4.09 (3.28) 3.93 (2.52) 4.33 (3.14) Group 0.32 .573 .003
Interaction 0.66 .518 .007
Phonological processing
 Phonological memory: Memory for Digits CTOPP-2 Intervention 55 10.44 (2.86) 11.33 (2.99) 11.60 (2.65) Stage 7.92 < .001 .077
Control 42 11.50 (3.19) 11.88 (3.62) 12.40 (2.58) Group 2.32 .131 .024
Interaction 0.47 .624 .005
 Phonological memory: Nonword Repetition CTOPP-2 Intervention 55 2.65 (2.78) 3.62 (3.75) 3.75 (3.64) Stage 5.81 .004 .057
Control 43 2.49 (3.31) 4.05 (3.63) 3.65 (3.41) Group 0.01 .914 .000
Interaction 0.01 .727 .003
 Rapid nonsymbolic naming: Rapid Color Naming CTOPP-2 Intervention 34 58.29 (18.86) 54.94 (20.13) 56.76 (21.95) Stage 3.47 .035 .060
Control 22 58.00 (15.58) 51.14 (12.88) 52.68 (16.35) Group 0.37 .548 .007
Interaction 0.57 .567 .010
 Rapid nonsymbolic naming: Rapid Object Naming CTOPP-2 Intervention 41 64.02 (19.77) 63.44 (21.20) 65.41 (23.44) Stage 0.96 .384 .013
Control 34 62.38 (12.61) 62.18 (17.49) 64.35 (18.82) Group 0.10 .749 .001
Interaction 0.02 .983 .000
Children’s participation and well-being
 Parent-reported communication outcomes FOCUS Intervention 29 253.4 (49.25) 256.8 (52.68) 261.1 (49.57) Stage 1.83 .167 .042
Control 15 256.5 (38.09) 269.2 (38.36) 267.5 (49.69) Group 0.27 .606 .006
Interaction 0.41 .668 .010
 Child-reported attitude score KiddyCAT Intervention 57 3.68 (2.42) 3.23 (2.61) 2.26 (2.39) Stage 7.99 < .001 .073
Control 46 3.76 (2.48) 3.61 (2.94) 3.15 (2.37) Group 1.25 .267 .012
Interaction 1.24 .292 .012
 Child-reported happy Image Not Available occurrences SPAA-C Intervention 56 6.95 (2.76) 6.41 (2.38) 5.90 (2.62) Stage 1.62 .200 .016
Control 44 5.60 (3.04) 5.87 (2.71) 5.64 (2.60) Group 3.13 .080 .030
Interaction 1.91 .151 .018
Note. DEAP = Diagnostic Evaluation of Articulation and Phonology, Phonology Assessment; ICS = Intelligibility in Context Scale; PWPA = Preschool Word and Print Awareness; CTOPP-2 = Comprehensive Test of Phonological Processing–Second Edition; FOCUS = Focus on the Outcomes of Children Under Six; KiddyCAT = Communication Attitude Test for Preschool and Kindergarten Children Who Stutter; SPAA-C = Speech Participation and Activity Assessment of Children.
Note. DEAP = Diagnostic Evaluation of Articulation and Phonology, Phonology Assessment; ICS = Intelligibility in Context Scale; PWPA = Preschool Word and Print Awareness; CTOPP-2 = Comprehensive Test of Phonological Processing–Second Edition; FOCUS = Focus on the Outcomes of Children Under Six; KiddyCAT = Communication Attitude Test for Preschool and Kindergarten Children Who Stutter; SPAA-C = Speech Participation and Activity Assessment of Children.×
×
Table 4. Outcomes of the intervention and control groups in the Sound Start Study: Per protocol.
Outcomes of the intervention and control groups in the Sound Start Study: Per protocol.×
Parameter Measure Group Valid n Stage 2/3, M (SD) Stage 5, M (SD) Stage 6, M (SD) Effect F p ηp 2
Speech production
 Percentage of consonants correct DEAP Intervention 22 72.87 (6.99) 78.28 (7.91) 79.29 (7.77) Stage 28.81 < .001 .324
Control 40 63.74 (11.96) 69.85 (13.88) 70.87 (13.30) Group 9.36 .003 .135
Interaction 0.09 .916 .001
 Primary intervention target: Probes Sound Start Study probes Intervention 22 64.83 (27.81) 45.04 (39.01) 43.44 (37.45) Stage 23.33 < .001 .283
Control 39 71.83 (29.04) 57.86 (37.09) 50.85 (36.36) Group 1.16 .286 .019
Interaction 0.49 .614 .008
 Intelligibility ICS Intervention 10 3.86 (0.42) 4.01 (0.32) 3.87 (0.47) Stage 1.48 .243 .008
Control 9 4.00 (0.43) 4.14 (0.47) 4.02 (0.31) Group 0.84 .372 .047
Interaction 0.00 .996 .000
Emergent literacy
 Letter knowledge Anthony et al. (2011)  Intervention 18 11.61 (9.56) 15.17 (9.54) 16.00 (9.59) Stage 13.27 < .001 .206
Control 35 5.74 (8.03) 7.11 (9.08) 9.31 (9.51) Group 7.63 .008 .130
Interaction 1.00 .371 .019
 Word and print awareness PWPA Intervention 22 6.50 (3.43) 7.23 (3.28) Stage 11.73 .001 .159
Control 42 5.50 (3.15) 7.12 (3.25) Group 0.50 .483 .008
Interaction 1.69 .198 .027
 Phonological awareness: Elision CTOPP-2 Intervention 22 2.23 (3.78) 3.32 (4.89) 3.36 (4.26) Stage 15.16 < .001 .216
Control 35 3.06 (4.06) 4.29 (4.00) 5.40 (4.22) Group 1.41 .241 .025
Interaction 2.11 .127 .037
 Phonological awareness: Blending Words CTOPP-2 Intervention 22 5.45 (4.70) 7.18 (5.67) 7.64 (4.94) Stage 19.06 < .001 .254
Control 36 3.72 (3.04) 5.64 (3.59) 6.24 (3.75) Group 2.26 .139 .039
Interaction 0.48 .898 .002
 Phonological awareness: Sound Matching CTOPP-2 Intervention 22 4.09 (3.81) 5.45 (4.34) 5.41 (5.39) Stage 3.01 .053 .052
Control 35 3.66 (3.06) 4.03 (2.47) 4.63 (3.14) Group 1.18 .283 .021
Interaction 0.54 .587 .010
Phonological processing
 Phonological memory: Memory for Digits CTOPP-2 Intervention 22 10.50 (3.25) 11.55 (3.10) 11.68 (2.23) Stage 6.14 .003 .100
Control 35 11.23 (3.18) 11.77 (2.96) 12.14 (2.55) Group 0.45 .505 .008
Interaction 0.33 .723 .006
 Phonological memory: Nonword Repetition CTOPP-2 Intervention 22 2.86 (2.95) 4.32 (4.91) 4.36 (3.81) Stage 1.68 .192 .030
Control 35 2.71 (3.42) 4.37 (3.73) 3.31 (3.52) Group 0.88 .353 .016
Interaction 0.67 .514 .012
 Rapid nonsymbolic naming: Rapid Color Naming CTOPP-2 Intervention 15 59.47 (22.53) 52.73 (22.16) 56.00 (24.08) Stage 2.86 .065 .082
Control 19 57.63 (16.09) 51.79 (13.52) 53.58 (17.48) Group 0.09 .771 .003
Interaction 0.04 .961 .001
 Rapid nonsymbolic naming: Rapid Object Naming CTOPP-2 Intervention 16 64.44 (25.88) 62.06 (27.53) 65.94 (29.47) Stage 1.82 .168 .041
Control 29 62.28 (12.79) 60.52 (16.91) 64.72 (19.46) Group 0.07 .790 .002
Interaction 0.05 .827 .001
Children's participation and well-being
 Parent-reported communication outcomes FOCUS Intervention 11 246.6 (49.23) 261.9 (39.04) 253.9 (36.79) Stage 1.07 .355 .056
Control 9 261.4 (25.74) 267.9 (47.03) 261.9 (54.87) Group 0.31 .584 .017
Interaction 0.19 .827 .011
 Child-reported attitude score KiddyCAT Intervention 22 3.32 (2.15) 3.36 (2.26) 2.45 (2.35) Stage 2.93 .057 .047
Control 39 3.87 (2.45) 3.51 (2.86) 3.21 (2.40) Group 0.83 .367 .014
Interaction 0.42 .657 .007
 Child-reported happy Image Not Available occurrences SPAA-C Intervention 21 7.14 (2.74) 6.38 (2.46) 6.00 (2.85) Stage 2.09 .128 .037
Control 36 6.11 (3.04) 6.47 (2.49) 5.72 (2.53) Group 0.48 .493 .009
Interaction 1.09 .341 .019
Note. DEAP = Diagnostic Evaluation of Articulation and Phonology, Phonology Assessment; ICS = Intelligibility in Context Scale; PWPA = Preschool Word and Print Awareness; CTOPP-2 = Comprehensive Test of Phonological Processing–Second Edition; FOCUS = Focus on the Outcomes of Children Under Six; KiddyCAT = Communication Attitude Test for Preschool and Kindergarten Children Who Stutter; SPAA-C = Speech Participation and Activity Assessment of Children.
Note. DEAP = Diagnostic Evaluation of Articulation and Phonology, Phonology Assessment; ICS = Intelligibility in Context Scale; PWPA = Preschool Word and Print Awareness; CTOPP-2 = Comprehensive Test of Phonological Processing–Second Edition; FOCUS = Focus on the Outcomes of Children Under Six; KiddyCAT = Communication Attitude Test for Preschool and Kindergarten Children Who Stutter; SPAA-C = Speech Participation and Activity Assessment of Children.×
Table 4. Outcomes of the intervention and control groups in the Sound Start Study: Per protocol.
Outcomes of the intervention and control groups in the Sound Start Study: Per protocol.×
Parameter Measure Group Valid n Stage 2/3, M (SD) Stage 5, M (SD) Stage 6, M (SD) Effect F p ηp 2
Speech production
 Percentage of consonants correct DEAP Intervention 22 72.87 (6.99) 78.28 (7.91) 79.29 (7.77) Stage 28.81 < .001 .324
Control 40 63.74 (11.96) 69.85 (13.88) 70.87 (13.30) Group 9.36 .003 .135
Interaction 0.09 .916 .001
 Primary intervention target: Probes Sound Start Study probes Intervention 22 64.83 (27.81) 45.04 (39.01) 43.44 (37.45) Stage 23.33 < .001 .283
Control 39 71.83 (29.04) 57.86 (37.09) 50.85 (36.36) Group 1.16 .286 .019
Interaction 0.49 .614 .008
 Intelligibility ICS Intervention 10 3.86 (0.42) 4.01 (0.32) 3.87 (0.47) Stage 1.48 .243 .008
Control 9 4.00 (0.43) 4.14 (0.47) 4.02 (0.31) Group 0.84 .372 .047
Interaction 0.00 .996 .000
Emergent literacy
 Letter knowledge Anthony et al. (2011)  Intervention 18 11.61 (9.56) 15.17 (9.54) 16.00 (9.59) Stage 13.27 < .001 .206
Control 35 5.74 (8.03) 7.11 (9.08) 9.31 (9.51) Group 7.63 .008 .130
Interaction 1.00 .371 .019
 Word and print awareness PWPA Intervention 22 6.50 (3.43) 7.23 (3.28) Stage 11.73 .001 .159
Control 42 5.50 (3.15) 7.12 (3.25) Group 0.50 .483 .008
Interaction 1.69 .198 .027
 Phonological awareness: Elision CTOPP-2 Intervention 22 2.23 (3.78) 3.32 (4.89) 3.36 (4.26) Stage 15.16 < .001 .216
Control 35 3.06 (4.06) 4.29 (4.00) 5.40 (4.22) Group 1.41 .241 .025
Interaction 2.11 .127 .037
 Phonological awareness: Blending Words CTOPP-2 Intervention 22 5.45 (4.70) 7.18 (5.67) 7.64 (4.94) Stage 19.06 < .001 .254
Control 36 3.72 (3.04) 5.64 (3.59) 6.24 (3.75) Group 2.26 .139 .039
Interaction 0.48 .898 .002
 Phonological awareness: Sound Matching CTOPP-2 Intervention 22 4.09 (3.81) 5.45 (4.34) 5.41 (5.39) Stage 3.01 .053 .052
Control 35 3.66 (3.06) 4.03 (2.47) 4.63 (3.14) Group 1.18 .283 .021
Interaction 0.54 .587 .010
Phonological processing
 Phonological memory: Memory for Digits CTOPP-2 Intervention 22 10.50 (3.25) 11.55 (3.10) 11.68 (2.23) Stage 6.14 .003 .100
Control 35 11.23 (3.18) 11.77 (2.96) 12.14 (2.55) Group 0.45 .505 .008
Interaction 0.33 .723 .006
 Phonological memory: Nonword Repetition CTOPP-2 Intervention 22 2.86 (2.95) 4.32 (4.91) 4.36 (3.81) Stage 1.68 .192 .030
Control 35 2.71 (3.42) 4.37 (3.73) 3.31 (3.52) Group 0.88 .353 .016
Interaction 0.67 .514 .012
 Rapid nonsymbolic naming: Rapid Color Naming CTOPP-2 Intervention 15 59.47 (22.53) 52.73 (22.16) 56.00 (24.08) Stage 2.86 .065 .082
Control 19 57.63 (16.09) 51.79 (13.52) 53.58 (17.48) Group 0.09 .771 .003
Interaction 0.04 .961 .001
 Rapid nonsymbolic naming: Rapid Object Naming CTOPP-2 Intervention 16 64.44 (25.88) 62.06 (27.53) 65.94 (29.47) Stage 1.82 .168 .041
Control 29 62.28 (12.79) 60.52 (16.91) 64.72 (19.46) Group 0.07 .790 .002
Interaction 0.05 .827 .001
Children's participation and well-being
 Parent-reported communication outcomes FOCUS Intervention 11 246.6 (49.23) 261.9 (39.04) 253.9 (36.79) Stage 1.07 .355 .056
Control 9 261.4 (25.74) 267.9 (47.03) 261.9 (54.87) Group 0.31 .584 .017
Interaction 0.19 .827 .011
 Child-reported attitude score KiddyCAT Intervention 22 3.32 (2.15) 3.36 (2.26) 2.45 (2.35) Stage 2.93 .057 .047
Control 39 3.87 (2.45) 3.51 (2.86) 3.21 (2.40) Group 0.83 .367 .014
Interaction 0.42 .657 .007
 Child-reported happy Image Not Available occurrences SPAA-C Intervention 21 7.14 (2.74) 6.38 (2.46) 6.00 (2.85) Stage 2.09 .128 .037
Control 36 6.11 (3.04) 6.47 (2.49) 5.72 (2.53) Group 0.48 .493 .009
Interaction 1.09 .341 .019
Note. DEAP = Diagnostic Evaluation of Articulation and Phonology, Phonology Assessment; ICS = Intelligibility in Context Scale; PWPA = Preschool Word and Print Awareness; CTOPP-2 = Comprehensive Test of Phonological Processing–Second Edition; FOCUS = Focus on the Outcomes of Children Under Six; KiddyCAT = Communication Attitude Test for Preschool and Kindergarten Children Who Stutter; SPAA-C = Speech Participation and Activity Assessment of Children.
Note. DEAP = Diagnostic Evaluation of Articulation and Phonology, Phonology Assessment; ICS = Intelligibility in Context Scale; PWPA = Preschool Word and Print Awareness; CTOPP-2 = Comprehensive Test of Phonological Processing–Second Edition; FOCUS = Focus on the Outcomes of Children Under Six; KiddyCAT = Communication Attitude Test for Preschool and Kindergarten Children Who Stutter; SPAA-C = Speech Participation and Activity Assessment of Children.×
×