A Randomized Controlled Trial for Children With Childhood Apraxia of Speech Comparing Rapid Syllable Transition Treatment and the Nuffield Dyspraxia Programme–Third Edition Purpose This randomized controlled trial compared the experimental Rapid Syllable Transition (ReST) treatment to the Nuffield Dyspraxia Programme–Third Edition (NDP3; Williams & Stephens, 2004), used widely in clinical practice in Australia and the United Kingdom. Both programs aim to improve speech motor planning/programming for children with apraxia of speech (CAS), ... Research Article
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Research Article  |   June 01, 2015
A Randomized Controlled Trial for Children With Childhood Apraxia of Speech Comparing Rapid Syllable Transition Treatment and the Nuffield Dyspraxia Programme–Third Edition
 
Author Affiliations & Notes
  • Elizabeth Murray
    The University of Sydney, Australia
  • Patricia McCabe
    The University of Sydney, Australia
  • Kirrie J. Ballard
    The University of Sydney, Australia
  • Disclosure: The authors have declared that no competing interests existed at the time of publication.
    Disclosure: The authors have declared that no competing interests existed at the time of publication.×
  • Correspondence to Elizabeth Murray: elizabeth.murray@sydney.edu.au
  • Editor: Jody Kreiman
    Editor: Jody Kreiman×
  • Associate Editor: Ben A. M. Maassen
    Associate Editor: Ben A. M. Maassen×
Article Information
Speech, Voice & Prosodic Disorders / Apraxia of Speech & Childhood Apraxia of Speech / Research Issues, Methods & Evidence-Based Practice / Speech, Voice & Prosody / Speech / Research Articles
Research Article   |   June 01, 2015
A Randomized Controlled Trial for Children With Childhood Apraxia of Speech Comparing Rapid Syllable Transition Treatment and the Nuffield Dyspraxia Programme–Third Edition
Journal of Speech, Language, and Hearing Research, June 2015, Vol. 58, 669-686. doi:10.1044/2015_JSLHR-S-13-0179
History: Received July 11, 2013 , Revised May 29, 2014 , Accepted February 13, 2015
 
Journal of Speech, Language, and Hearing Research, June 2015, Vol. 58, 669-686. doi:10.1044/2015_JSLHR-S-13-0179
History: Received July 11, 2013; Revised May 29, 2014; Accepted February 13, 2015
Web of Science® Times Cited: 9

Purpose This randomized controlled trial compared the experimental Rapid Syllable Transition (ReST) treatment to the Nuffield Dyspraxia Programme–Third Edition (NDP3; Williams & Stephens, 2004), used widely in clinical practice in Australia and the United Kingdom. Both programs aim to improve speech motor planning/programming for children with apraxia of speech (CAS), but they differ in types of stimuli used, level of stimulus complexity at initiation of treatment, and the principles of motor learning that they apply.

Method Treatment was delivered to 26 children with mild to severe CAS aged 4–12 years through trained and supervised speech-language pathology students in 1-hr sessions, 4 days a week for 3 weeks at a university clinic. Articulation and prosodic accuracy were assessed at pretreatment, 1 week, 1 month, and 4 months posttreatment using blinded independent assessors to compare treatment, maintenance, and generalization effects.

Results The ReST and NDP3 treatments demonstrated large treatment effects. ReST maintained treatment gains from 1-week to 4-months posttreatment more effectively than the NDP3. Significant generalization to untreated stimuli was observed for both ReST and NDP3.

Conclusions ReST and NDP3 have strong evidence of treatment and generalization gains in children with CAS when delivered intensively. Overall, ReST has greater external evidence from multiple sources but both treatments have support for clinical use.

Idiopathic childhood apraxia of speech (CAS; known in the United Kingdom as developmental verbal dyspraxia) is currently considered a motor speech disorder of planning and/or programming (e.g., American Speech-Language-Hearing Association [ASHA], 2007; Nijland, Maassen, & van der Meulen, 2003). Although there is no validated assessment procedure available for CAS, there is consensus on three features of the disorder: “(a) inconsistent errors on consonants and vowels in repeated productions of syllables or words, (b) lengthened and disrupted co-articulatory transitions between sounds and syllables, and (c) inappropriate prosody, especially in the realization of lexical or phrasal stress” (ASHA, 2007).1  Longitudinal studies suggest that idiopathic CAS is persistent throughout childhood and potentially into adulthood, frequently disrupting development of literacy skills (e.g., learning letter-sound relationships for decoding new words), social communication, and academic and vocational potential (e.g., Jacks, Marquardt, & Davis, 2006; Lewis, Freebairn, Hansen, Iyengar, & Taylor, 2004; Stackhouse & Snowling, 1992). The three consensus-based diagnostic features are thought to reflect impaired motor control; therefore, efficacious treatment for CAS on the basis of the current consensus should provide intensive motor treatment to affect change across these features (ASHA, 2007).
Peer-reviewed research in CAS treatment to date consists of single-subject designs (Murray, McCabe, & Ballard, 2014), which are important in developing viable treatments for larger scale testing and can be useful in applying treatment to particular client presentations that have been studied (Hegde, 2007). However, single-subject designs can often be limited by heterogeneous participants and insufficient experimental control measures (Byiers, Reichle, & Symons, 2012; Robey, 2004). No randomized control trials (RCTs) have been conducted to examine treatment efficacy for CAS (Morgan & Vogel, 2008, 2009; Watts, 2009).
RCTs actively compare an experimental treatment to a control (no treatment, sham treatment, or comparison to a commonly used treatment) to determine relative efficacy. Such designs permit controlled comparisons across treatments when designed with high internal and external validity to reduce bias (Maher, Sherrington, Herbert, Moseley, & Elkins, 2003; Moher, Schulz, & Altman, 2001). This comparison is difficult in within-subjects alternating treatments or crossover designs, which are susceptible to interference and order effects between treatments (e.g., Lundeborg & McAllister, 2007; Martikainen & Korpilahti, 2011). RCTs are also important for testing treatments on larger samples with effective randomization to wash out individual differences across participants. Such studies may allow greater generalization and clinical application of the results to other children with the same disorder, giving clinicians more confidence that their client will benefit from the treatment as individual clients do not often match the characteristics of those who participated in single-case experimental designs.
This study compares the efficacy of two treatment approaches for CAS within a RCT. The experimental Rapid Syllable Transition (ReST) treatment has sufficient external evidence to warrant inclusion (Murray et al., 2014). The comparative treatment is the Nuffield Dyspraxia Programme–Third Edition (NDP3; Williams & Stephens, 2004), which is the most commonly used treatment of CAS in Australia (Baker & McLeod, 2011).
ReST
ReST is a treatment approach designed to target the core features of CAS (Ballard, Robin, McCabe, & McDonald, 2010; McCabe, Macdonald-D'Silva, van Rees, Ballard, & Arciuli, 2014; Murray, McCabe, & Ballard, 2012; Staples, McCabe, Ballard, & Robin, 2008). It explicitly addresses: (a) segmental (sound) consistency through improving accuracy, (b) rapid and fluent transitions from one segment and syllable to the next, and (c) accurate production of lexical stress, and demands accuracy on all three aspects simultaneously. It uses polysyllabic pseudowords (nonwords) intended to treat underlying motor patterns and to mimic novel word learning (Gierut, Morrisette, & Ziemer, 2010; Maas, Barlow, Robin, & Shapiro, 2002). It applies the principles of motor learning approach (Schmidt & Lee, 2011). In brief, each session is separated into prepractice and practice. Prepractice serves to introduce the skills and stimuli to be trained and to provide opportunities to attempt the new skills with clinician support and cuing in order to experience correct productions and recognize errors. The practice phase is the majority of the session and involves a high number of trials (≥100), variable practice (i.e., training more than one variation of a skill), as well as random order of stimulus presentation and low frequency feedback on knowledge of results (KR; feedback on accuracy only) presented with a 3- to 5-s delay between response and feedback. In earlier research, the treatment has been provided intensively in 10 to 12 one-hr sessions across 3 weeks. As such, ReST systematically applies key principles of motor learning (PML) that have been shown to maximize long-term maintenance and transfer of trained motor skills in both limb and speech systems (Bislick, Weir, Spencer, Kendall, & Yorkston, 2012; Maas et al., 2008; Wulf, Shea, & Lewthwaite, 2010). Table 1 presents a list of the PML used in ReST and a comparison with the NDP3.
Table 1. Treatment explanation and comparison of Rapid Syllable Transition (ReST) treatment and Nuffield Dyspraxia Programme–Third Edition (NDP3).
Treatment explanation and comparison of Rapid Syllable Transition (ReST) treatment and Nuffield Dyspraxia Programme–Third Edition (NDP3).×
ReST NDP3
Treatment goals/components Prepractice: To learn to say five pseudoword stimuli accurately with cues. Three individualized goals chosen for each participant across a hierarchy (Treatment Planning and Progression: Williams & Stephens, 2004).
Practice: To accurately produce 80% of 100 random trials.
Stimuli used in treatment 20 individualized pseudowords: At least 15 individualized, real-word pictured stimuli (minimum of five for each goal selected from the manual using psycholinguistics):
10 weak–strong lexical stress (e.g. “begarter” /bəgatə/) or 10 strong–weak lexical stress (e.g. “farbegee” /fabəgi/); final syllables were either strong ee (/i/) or weak er (/ə/).  • Phonotactic/prosodic goal (new structures/old sounds).
At either two syllable (CVCV) or three syllable (CVCVCV) level initially.  • Articulation goal (old structures/new sounds).
High target complexity: Highest level for child (that is stimulable). Low target complexity: Next step from child's current level.
Elicitation method Imitation of clinician's production. Spontaneous naming of picture stimuli.
Reading stimuli cards if participant was a fluent reader.
Treatment trials Prepractice: At least 5 trials (10–15 mins) Per goal: 30–40 trials (18 min each)
Practice: 100 trials (45–50 mins) Total trials per session: 100–120
Total trials per session: 100–120
Teaching strategies/cues Prepractice: Verbal instructions, modeling, tapping blocks, and breaking word up into parts and then putting them together again and orthographic stimuli. Prepractice: Verbal instructions, modeling, articulation, and visual-tactile cues (e.g., cued articulation) and pictured stimuli.
Practice: No cues. Practice: Not used.
Feedback Prepractice: KP for all trials. Prepractice: KP feedback for all trials. Correct responses followed by three repetitions of the same stimuli with feedback.
Practice: KR feedback (right/wrong) for a random 50% of the 100 trials after a 3-s delay. Practice: Not used.
Progression Practice: 80% accuracy over two sessions.  • 90% accuracy per stimuli.
 • For two syllable words move up to three syllable words.  • Add new stimuli at same level.
 • For three syllable words move up to carrier phrases (e.g. “Can I have a begarter?”)  • Achieved stimuli moved into maintenance.
Once five stimuli are achieved > next level of hierarchy
Summary of principles of motor learning Prepractice/acquisition-based: 25% of session Prepractice/acquisition-based: 100% of session
(Maas et al., 2008; McIlwaine, Madill, & McCabe, 2010)  • Blocked random practice  • Blocked random practice (approx. five practices of one stimulus before moving on to the next randomly selected)
 • Feedback 100% KP  • Feedback 100% KP
 • Cues for all incorrect productions  • Cues for all incorrect productions
Practice/ maintenance and generalization-based: 75% of session Practice/maintenance and generalization-based: Not done
 • No cues
 • Random practice
Feedback on outcome/results randomly for 50% of trials after 3-s delay
Note. KP = knowledge of performance; KR = knowledge of results.
Note. KP = knowledge of performance; KR = knowledge of results.×
Table 1. Treatment explanation and comparison of Rapid Syllable Transition (ReST) treatment and Nuffield Dyspraxia Programme–Third Edition (NDP3).
Treatment explanation and comparison of Rapid Syllable Transition (ReST) treatment and Nuffield Dyspraxia Programme–Third Edition (NDP3).×
ReST NDP3
Treatment goals/components Prepractice: To learn to say five pseudoword stimuli accurately with cues. Three individualized goals chosen for each participant across a hierarchy (Treatment Planning and Progression: Williams & Stephens, 2004).
Practice: To accurately produce 80% of 100 random trials.
Stimuli used in treatment 20 individualized pseudowords: At least 15 individualized, real-word pictured stimuli (minimum of five for each goal selected from the manual using psycholinguistics):
10 weak–strong lexical stress (e.g. “begarter” /bəgatə/) or 10 strong–weak lexical stress (e.g. “farbegee” /fabəgi/); final syllables were either strong ee (/i/) or weak er (/ə/).  • Phonotactic/prosodic goal (new structures/old sounds).
At either two syllable (CVCV) or three syllable (CVCVCV) level initially.  • Articulation goal (old structures/new sounds).
High target complexity: Highest level for child (that is stimulable). Low target complexity: Next step from child's current level.
Elicitation method Imitation of clinician's production. Spontaneous naming of picture stimuli.
Reading stimuli cards if participant was a fluent reader.
Treatment trials Prepractice: At least 5 trials (10–15 mins) Per goal: 30–40 trials (18 min each)
Practice: 100 trials (45–50 mins) Total trials per session: 100–120
Total trials per session: 100–120
Teaching strategies/cues Prepractice: Verbal instructions, modeling, tapping blocks, and breaking word up into parts and then putting them together again and orthographic stimuli. Prepractice: Verbal instructions, modeling, articulation, and visual-tactile cues (e.g., cued articulation) and pictured stimuli.
Practice: No cues. Practice: Not used.
Feedback Prepractice: KP for all trials. Prepractice: KP feedback for all trials. Correct responses followed by three repetitions of the same stimuli with feedback.
Practice: KR feedback (right/wrong) for a random 50% of the 100 trials after a 3-s delay. Practice: Not used.
Progression Practice: 80% accuracy over two sessions.  • 90% accuracy per stimuli.
 • For two syllable words move up to three syllable words.  • Add new stimuli at same level.
 • For three syllable words move up to carrier phrases (e.g. “Can I have a begarter?”)  • Achieved stimuli moved into maintenance.
Once five stimuli are achieved > next level of hierarchy
Summary of principles of motor learning Prepractice/acquisition-based: 25% of session Prepractice/acquisition-based: 100% of session
(Maas et al., 2008; McIlwaine, Madill, & McCabe, 2010)  • Blocked random practice  • Blocked random practice (approx. five practices of one stimulus before moving on to the next randomly selected)
 • Feedback 100% KP  • Feedback 100% KP
 • Cues for all incorrect productions  • Cues for all incorrect productions
Practice/ maintenance and generalization-based: 75% of session Practice/maintenance and generalization-based: Not done
 • No cues
 • Random practice
Feedback on outcome/results randomly for 50% of trials after 3-s delay
Note. KP = knowledge of performance; KR = knowledge of results.
Note. KP = knowledge of performance; KR = knowledge of results.×
×
Fourteen participants with CAS, aged between 3 and 10 years (13 boys), have participated in various preliminary ReST studies, including a case series/quasi-experimental design (Staples et al., 2008) and two single-case experimental designs (Ballard et al., 2010; McCabe et al., 2014). The response and timeframe for typically developing children to learn similar novel pseudowords has also been tested (van Rees, Ballard, McCabe, Macdonald-D'Silva, & Arciuli, 2012). Across the studies of participants with CAS, 12 of the 14 demonstrated a treatment effect and no change in control items. Significant improvements after treatment were noted for percent vowels correct (PVC; Staples et al., 2008), perceptual accuracy of lexical stress production (Ballard et al., 2010; McCabe et al., 2014), and acoustically analyzed lexical stress production using the Pairwise Variability Index (Ballard et al., 2010). Maintenance was demonstrated for eight of the 14 children, up to 4 weeks posttreatment (Ballard et al., 2010; McCabe et al., 2014) and for two of eight children for PVC up to 6 months posttreatment (Staples et al., 2008). There was significant generalization of treatment effects to connected speech (McCabe et al., 2014; Staples et al., 2008) and other pseudoword strings, reflecting the ability to tackle novel words (Ballard et al., 2010). Although children with CAS did not reach mastery of skill within 12 sessions in any of these studies, typically developing children took an average of five sessions to meet a mastery criterion (van Rees et al., 2012). These preliminary studies with CAS have experimentally determined early efficacy for ReST treatment and set the foundation for this Phase III study.
NDP3
The NDP3 was selected as a comparison treatment as it is the most commonly used treatment in Australia (Baker & McLeod, 2011; see Table 1) with similar frequency of use being reported in the United Kingdom (Joffe & Pring, 2008). It is a comprehensive, commercially available treatment reported to be appropriate for use with children between 4 and 12 years of age (Williams & Stephens, 2004, chapter 7). The third edition reports using a psycholinguistic framework (Stackhouse & Wells, 1997) to address motor planning and programming “from the bottom up, starting from isolated speech sounds and progressing from simple to more complex syllable shapes, then to sentences and connected speech” (Williams & Stephens, 2010, pp. 167–168). Goals are based on segments, syllable shapes, or prosody, applied via a program hierarchy where motor learning is considered to require repetition, elicitation, and immediate, specific knowledge of performance (KP) or KR feedback on all production trials (Williams & Stephens, 2004, 2010). As such, the NDP3 applies most of the strategies typically applied in the prepractice phase of a PML approach, designed to instantiate new skills with a gradual shift to less cuing support and spontaneous productions. The published treatment resources also incorporate linguistic concepts such as phonological contrasts (auditory discrimination, minimal pairs), with morphosyntactic and phrasal stress stimuli in later steps of the program. Recommended treatment sessions are 1 hr, once or twice per week, with daily home practice of approximately 20 min between sessions. The number of production trials is not specified.
The program has been used in a number of different formats in both clinical and research reports. Some studies have used it according to the manual (Belton, 2006; Pagnamenta & Williams, 2009) where three goals across the hierarchy are selected and addressed in each treatment session, providing variable practice of skills (Williams & Stephens, 2004, p. 75). Other usage has been more eclectic, often combining it with another treatment such as Core Vocabulary (Teal, 2005) or phonological awareness intervention (Watson & Gillon, 1999).
No published peer-reviewed evidence exists for using the NDP3 alone for CAS despite its common use in clinical practice over a 30-year period (cf. Lundeborg & McAllister, 2007). Unpublished master's dissertations (Belton, 2006; Teal, 2005) and two conference presentations (Pagnamenta & Williams, 2009; Watson & Gillon, 1999) treated a total of seven participants, aged between 4 and 7 years (four boys) with reported but not verifiable developmental verbal dyspraxia (i.e., CAS). Of these, six out of seven participants made treatment gains and demonstrated generalization to improved consonant accuracy, intelligibility, and reduced inconsistency, however, in the context of poor experimental control. This RCT will provide more rigorous efficacy data for the NDP3 than previously presented when used according to the published manual in the context of greater treatment intensity (Williams & Stephens, 2004).
Comparison of ReST and NDP3
Both ReST and the NDP3 are tested here as programs of treatment, following procedures in respective treatment manuals (Murray et al., 2012; Williams & Stephens, 2004). Both are motor treatments in that (a) the stimuli are selected on the basis of motor sequencing and phonotactics rather than linguistic meaning, (b) motor cues are given, not meaning-based linguistic cuing, (c) principles of motor learning are purposefully used in designing these treatments, even for the NDP3 using now outdated principles, and (d) there is a focus on high intensity practice over multiple sessions a week. Both treatments also purport to address the three core consensus-based features of CAS (ASHA, 2007). The high criterion level (80% or 90%) and large number of trials (100) across relatively few stimuli (15–20) is aimed to develop accuracy and consistency of production. ReST works on the three features simultaneously within two to three syllable pseudowords, considered as high complexity and whole-task activities in the PML framework, whereas the NDP3 uses lower complexity stimuli targeting one feature at a time across three separate goals, considered as low complexity and part-task activities in the PML framework.
Aims and Hypotheses
This RCT compared the efficacy of the experimental ReST treatment to the NDP3 program, commonly used in practice in Australia, for 26 children with idiopathic CAS aged between 4 and 12 years. We formulated the following hypotheses
  1. Treatment effects from pretreatment to within 1-week posttreatment would be similar for both treatments, due to both having high treatment intensity and addressing the CAS core consensus-based features (ASHA, 2007).

  2. ReST treatment would result in greater maintenance of treatment effects at 1 month and 4 months posttreatment than NDP3 treatment, due to use of facilitatory PML including high-target complexity whole-task activities.

  3. ReST treatment would result in greater generalization of treatment effects to untreated but related speech behaviors at 1 week, 1 month, and 4 months posttreatment than NDP3 treatment, due to use of facilitatory PML including high-target complexity whole-task activities.

In addition to the primary outcomes, secondary outcomes were assessed to determine generalization effects to connected speech (imitation of more than three word combinations), segmental and prosodic accuracy on the Single-Word Test of Polysyllables (Gozzard, Baker, & McCabe, 2004) and Goldman-Fristoe Test of Articulation–Second Edition (GFTA-2; Goldman & Fristoe, 2000) and inconsistency using the Diagnostic Evaluation of Articulation and Phonology (DEAP; Dodd, Hua, Crosbie, Holm, & Ozanne, 2002) Inconsistency subtest.
Method
The study design was a parallel group RCT. This trial was approved by the Human Research Ethics Committee at the University of Sydney (Unique Trial Number: U1111-1132-5952 and Australian New Zealand Clinical Trials Registry number: ACTRN12612000744853). The protocol for this RCT, which includes detailed description of the treatments, is publicly available (Murray et al., 2012).
Participants
Participants were recruited between September 2010 and January 2012 via emails and flyers sent to community-based speech-language pathologists (SLPs) in Australia. Children had to meet the following inclusion criteria to participate: (a) clinical diagnosis of confirmed CAS (see below), (b) aged between 4 and 12 years at the time of treatment, (c) a standard score of ≥85 for the receptive language score from the Clinical Evaluation of Language Fundamentals–Fourth Edition (CELF-4; Wiig, Secord, & Semel, 2006) or CELF-Preschool–Second Edition (CELF-P2; Semel, Wiig, & Secord, 2006), (d) normal or adjusted-to-normal hearing and vision, (e) the child and at least one parent being native Australian English speakers, and (f) no other diagnosed developmental or genetic disorders (e.g. dysarthria, autism, or intellectual disability).
To begin with, referring sources were interviewed by telephone to identify any contraindications to the listed inclusion criteria. Of 72 children referred, 21 were excluded at this point and four additional families declined the invitation to participate, due to the timing and intensive nature of the treatment. The remaining 47 children attended a 2-hr assessment to confirm diagnosis of idiopathic CAS and suitability for inclusion. This assessment included a case history questionnaire, hearing screening, the CELF-4 or CELF-P2 Australian Standardizations, and the Oral and Speech Motor Protocol (Robbins & Klee, 1987) to rule out uncorrected hearing impairment, delayed receptive language skills, and other motor speech or oral structural diagnoses, respectively (McCauley, Tambyraja, & Daher-Twersky, 2012). The DEAP Inconsistency subtest, Single-Word Test of Polysyllables (Gozzard, Baker, & McCabe, 2004, 2008), and a 50-utterance connected speech sample were used to generate speech samples for perceptually judging presence and severity of CAS. That is, the first two authors independently diagnosed CAS by applying the ASHA (2007)  and the Strand 10-point CAS feature (Shriberg, Potter, & Strand, 2009) checklists to the speech samples (Murray, McCabe, Heard, & Ballard, 2015). CAS was judged present when all three features in the ASHA consensus-based checklist were present and at least four of the 10 features in the Strand checklist were present across three different speech tasks.
Of the 47 children assessed, 28 were confirmed to have CAS and met all inclusion criteria, with 100% interrater reliability. Of these 28, two withdrew from participation due to difficulty with transport and 26 (18 boys, eight girls) received the treatment. Further details of the diagnostic process and results are detailed in Murray, McCabe, Heard, and Ballard (2015) .
Power calculations on the basis of earlier studies of ReST that included 14 participants indicated that a sample size of at least 12 participants was needed to detect a treatment effect for ReST alone with a power of .80 and alpha level of 0.05 (Cohen's d = 1.36; it was not possible to generate estimates for the NDP3). The final sample size of 26 (13 per group) was used in case of participant attrition and as a reliable estimate for detecting a difference between the two treatments. Figure 1 shows the flow of participants through the study (adapted from the CONSORT statement for nonpharmacological RCTs; Boutron et al., 2008). Table 2 provides a summary of the ReST and NDP3 groups' assessment results. No information on race, ethnicity, or socioeconomic status was collected.
Figure 1.

CONSORT flow chart of participant assignment, treatment, and follow up. aEach therapist saw two participants, one from each treatment group.

 CONSORT flow chart of participant assignment, treatment, and follow up. aEach therapist saw two participants, one from each treatment group.
Figure 1.

CONSORT flow chart of participant assignment, treatment, and follow up. aEach therapist saw two participants, one from each treatment group.

×
Table 2. Group comparison of pretreatment variables.
Group comparison of pretreatment variables.×
Variable assessed ReST group (n = 13)
NDP3 group (n = 13)
F p
M (SD) Range M (SD) Range
Demographic
 Age in months 72.8 (27.5) [48–142] 62.5 (23.0) [48–120] 1.08 .31
 Sex 10 boys, 3 girls 8 boys, 5 girls 0.69 .42
 Had previous speech treatment? 13/13 13/13
Primary outcome measures at baseline
 Accuracy on items treated 10.8 (8.6) [0–28] 30.3 (20.3) [3–69] 1.53 .23
 Accuracy on items expected to generalize
  Untreated real-word 45.7 (15.1) [22–75] 44.0 (13.7) [24–66] 0.1 .76
  Untreated pseudoword 8.5 (9.7) [0–30] 11.1 (9.1) [1–28] 0.48 .49
Secondary outcome measures at baseline
 Connected speech (imitation accuracy > three word combinations) 35.2 (24.1) [0–81] 29.8 (22.9) [0–70] 0.32 .58
 DEAP Inconsistency 61.4 (12.6) [44–80] 65.8 (12.3) [44–88] 0.83 .37
 Single Word Test of Polysyllables
  PPC 53.9 (14.5) [25–81] 50.5 (16.9) [21–77] 0.31 .59
  PVC 51.7 (10.4) [39–70] 50.1 (13.1) [25–70] 0.12 .74
  PCC 56.2 (19.8) [28–93] 51.0 (21.7) [18–90] 0.41 .53
  Percent lexical stress matches 10.8 (7.4) [2–26] 9.1 (11.3) [0–42] 0.21 .66
 GFTA-2
 Standard score 66.0 (21.5) [40–97] 68.2 (20.4) [44–97] 0.21 .66
  PPC 65.7 (16.4) [41–92] 64.0 (13.9) [37–86] 0.07 .72
  PVC 71.3 (12.9) [51–93] 66.3 (14.8) [39–87] 0.84 .37
  PCC 57.1 (21.8) [30–97] 56.5 (22.4) [21–89] 0.01 .94
  Percent lexical stress matches 69.2 (19.8) [14–93] 56.9 (21.4) [19–86] 2.31 .14
 Severity ratings (based on Polysyllabic PCC)
  Severe n = 5 n = 7
  Moderate–severe n = 4 n = 3
  Mild–moderate n = 2 n = 2
  Mild n = 2 n = 1
 Language scores
  CELF-P2 / CELF-4 receptive language score 99.3 (9.1) [85–116] 105.3 (12.7) [86–130] 0.56 .46
  CELF-P2 / CELF-4 expressive language score 94.8 (15.3) [70–116] 101.6 (8.6) [88-115] 0.58 .81
Note. Bold designates pseudowords; — = not assessed. ReST = Rapid Syllable Transition treatment; NDP3 = Nuffield Dyspraxia Programme–Third Edition; F = ANOVA statistic; p = significance set at 0.05; DEAP Inconsistency = Diagnostic Evaluation of Articulation and Phonology Inconsistency test; PPC = percent phonemes correct; PVC = percent vowels correct; PCC = percent consonants correct; GFTA-2 = Goldman-Fristoe Test of Articulation–Second Edition; CELF-P2 = Clinical Evaluation of Language Fundamentals-Preschool–Second Edition; CELF-4 = Clinical Evaluation of Language Fundamentals–Fourth Edition.
Note. Bold designates pseudowords; — = not assessed. ReST = Rapid Syllable Transition treatment; NDP3 = Nuffield Dyspraxia Programme–Third Edition; F = ANOVA statistic; p = significance set at 0.05; DEAP Inconsistency = Diagnostic Evaluation of Articulation and Phonology Inconsistency test; PPC = percent phonemes correct; PVC = percent vowels correct; PCC = percent consonants correct; GFTA-2 = Goldman-Fristoe Test of Articulation–Second Edition; CELF-P2 = Clinical Evaluation of Language Fundamentals-Preschool–Second Edition; CELF-4 = Clinical Evaluation of Language Fundamentals–Fourth Edition.×
Table 2. Group comparison of pretreatment variables.
Group comparison of pretreatment variables.×
Variable assessed ReST group (n = 13)
NDP3 group (n = 13)
F p
M (SD) Range M (SD) Range
Demographic
 Age in months 72.8 (27.5) [48–142] 62.5 (23.0) [48–120] 1.08 .31
 Sex 10 boys, 3 girls 8 boys, 5 girls 0.69 .42
 Had previous speech treatment? 13/13 13/13
Primary outcome measures at baseline
 Accuracy on items treated 10.8 (8.6) [0–28] 30.3 (20.3) [3–69] 1.53 .23
 Accuracy on items expected to generalize
  Untreated real-word 45.7 (15.1) [22–75] 44.0 (13.7) [24–66] 0.1 .76
  Untreated pseudoword 8.5 (9.7) [0–30] 11.1 (9.1) [1–28] 0.48 .49
Secondary outcome measures at baseline
 Connected speech (imitation accuracy > three word combinations) 35.2 (24.1) [0–81] 29.8 (22.9) [0–70] 0.32 .58
 DEAP Inconsistency 61.4 (12.6) [44–80] 65.8 (12.3) [44–88] 0.83 .37
 Single Word Test of Polysyllables
  PPC 53.9 (14.5) [25–81] 50.5 (16.9) [21–77] 0.31 .59
  PVC 51.7 (10.4) [39–70] 50.1 (13.1) [25–70] 0.12 .74
  PCC 56.2 (19.8) [28–93] 51.0 (21.7) [18–90] 0.41 .53
  Percent lexical stress matches 10.8 (7.4) [2–26] 9.1 (11.3) [0–42] 0.21 .66
 GFTA-2
 Standard score 66.0 (21.5) [40–97] 68.2 (20.4) [44–97] 0.21 .66
  PPC 65.7 (16.4) [41–92] 64.0 (13.9) [37–86] 0.07 .72
  PVC 71.3 (12.9) [51–93] 66.3 (14.8) [39–87] 0.84 .37
  PCC 57.1 (21.8) [30–97] 56.5 (22.4) [21–89] 0.01 .94
  Percent lexical stress matches 69.2 (19.8) [14–93] 56.9 (21.4) [19–86] 2.31 .14
 Severity ratings (based on Polysyllabic PCC)
  Severe n = 5 n = 7
  Moderate–severe n = 4 n = 3
  Mild–moderate n = 2 n = 2
  Mild n = 2 n = 1
 Language scores
  CELF-P2 / CELF-4 receptive language score 99.3 (9.1) [85–116] 105.3 (12.7) [86–130] 0.56 .46
  CELF-P2 / CELF-4 expressive language score 94.8 (15.3) [70–116] 101.6 (8.6) [88-115] 0.58 .81
Note. Bold designates pseudowords; — = not assessed. ReST = Rapid Syllable Transition treatment; NDP3 = Nuffield Dyspraxia Programme–Third Edition; F = ANOVA statistic; p = significance set at 0.05; DEAP Inconsistency = Diagnostic Evaluation of Articulation and Phonology Inconsistency test; PPC = percent phonemes correct; PVC = percent vowels correct; PCC = percent consonants correct; GFTA-2 = Goldman-Fristoe Test of Articulation–Second Edition; CELF-P2 = Clinical Evaluation of Language Fundamentals-Preschool–Second Edition; CELF-4 = Clinical Evaluation of Language Fundamentals–Fourth Edition.
Note. Bold designates pseudowords; — = not assessed. ReST = Rapid Syllable Transition treatment; NDP3 = Nuffield Dyspraxia Programme–Third Edition; F = ANOVA statistic; p = significance set at 0.05; DEAP Inconsistency = Diagnostic Evaluation of Articulation and Phonology Inconsistency test; PPC = percent phonemes correct; PVC = percent vowels correct; PCC = percent consonants correct; GFTA-2 = Goldman-Fristoe Test of Articulation–Second Edition; CELF-P2 = Clinical Evaluation of Language Fundamentals-Preschool–Second Edition; CELF-4 = Clinical Evaluation of Language Fundamentals–Fourth Edition.×
×
Intervention
Participants were randomly assigned to one of the two treatments, ReST or NDP3, using concealed allocation with opaque envelopes by a person independent of the research team. Allocation was revealed after baseline assessment was completed. There were no significant differences between the two groups for any baseline variables (i.e., age, sex), primary and secondary outcome measures, and CAS severity, indicating that randomization was successful (see Table 2). CAS severity was measured using percentage of consonants correct (PCC; Shriberg, Austin, Lewis, McSweeny, & Wilson, 1997) from the Single-Word Test of Polysyllables and the standard score from the GFTA-2.
Dose was controlled across ReST and NDP3. Treatment was delivered over 12 one-hr sessions, scheduled 4 days a week for 3 weeks in school vacation time in January 2011, July 2011, and January 2012 with a maximum of 10 participants per block. Treatments were provided according to operationalized manuals (see Table 1, and the published protocol: Murray et al., 2012). ReST sessions had an average of 100.4 production trials (SD = 0.9) and NDP3 had an average of 101.3 (SD = 1.2). The difference in number of production trials between groups was not significant, F(1, 25) = 3.149, p = .149.
Student SLPs provided the therapy under the supervision of the first two authors. Clinicians received several days of training in providing both treatments and also in transcription and data collection until interrater reliability above 85% was achieved (Kratochwill et al., 2010). To control for any clinician effect, each clinician was allocated two participants and conducted two sessions per day—one in NDP3 for one participant and one in ReST for the other participant. The clinician treated the same participants for the duration of the treatment block. Order of treatments delivered each day was randomized across clinicians. Although clinicians were aware that two treatment approaches were being compared, they were blinded to the study hypotheses. Interference from one treatment to the other was minimized by monitoring treatment fidelity every session.
Caregivers were blinded to the name of the treatment their child was receiving, but could observe sessions through a one-way mirror and could speak to other caregivers in the waiting room. The child's treatment, goals, progress, and beneficial cues were provided in a report to caregivers after the 1-week posttreatment probes. No stimuli were provided to inhibit further practice prior to the 1-month posttreatment assessment.
ReST
The ReST treatment involved participants practicing production of 20 pseudowords, aiming for 80% accuracy in perceptually judged simultaneous articulation, co-articulation, and prosodic production over two consecutive sessions to step up to the next goal level. The three goal levels within the treatment were: (a) two-syllable C1V1C2V2 (e.g., /bəgu/ or /fabə/), (b) three-syllable C1V1C2V2C3V3 (e.g., /bəguti/ or /fabəgə/), and (c) three-syllable pseudowords as final noun within carrier phrases (e.g., “Can I have a /bəguti/?”). The participants' initial goal level was selected on the basis of performance in initial diagnostic testing, prior to the pretreatment experimental probe. The consonant segments in the stimuli were individualized for each participant to ensure that all sounds targeted were at least 10% stimulable and were maximally different fricative and plosive sounds (e.g. /b, f, t, g/), on the basis of pretreatment results. Half of the stimuli had a strong–weak (strong/weak) stress pattern and half weak–strong (weak/strong), with the third syllable being either strong using ee (/i/) or weak using er as per Australian English pronunciation (/ə/). All pseudowords had a high phonotactic probability (M. Vitevitch, 2004; M. S. Vitevitch & Luce, 1998, 2004) and were orthographically biased to facilitate selection of the targeted stress pattern in reading aloud by the literate children or by the clinician for modeling for preliterate children (Arciuli & Cupples, 2007; Seva, Monaghan, & Arciuli, 2009).
Treatment sessions had two components: prepractice and practice, on the basis of the PML approach (Schmidt & Lee, 2011). Prepractice (about 10–15 min of each session) aimed to elicit at least five correct productions of any of the 20 stimuli, using imitation, phonetic placement cues, tapping out the stress pattern, segmenting and blending, and prosodic cues, as well as KP feedback after every production. In practice (about 50 min of each session), each participant worked towards the production goal of 80% accuracy with no cues given across 100 trials (i.e., 20 treated items, five times each). Practice was divided into five blocks of 20 trials. In each block, each of the 20 treated items was presented once, in random order. KR feedback was provided 50% of the time on a decreasing scale (i.e., on nine of the first 10 trials, down to only one of the final 10 trials). Once the criterion of 80% correct across the 100 trials was met over two consecutive sessions, the participant stepped up to the next goal level. If participants met the criterion for phrases, they would then cease treatment. In the present study, the only variation to the published protocol was that if a participant produced no correct responses within two 20-item blocks of practice, the clinician inserted an additional block of prepractice to avoid excessive practice of erroneous forms (as per Macdonald-D'Silva, 2009, and McCabe et al., 2014).
NDP3
The NDP3 was delivered as stated in the published program and subsequent book chapter (Williams & Stephens, 2004, 2010). The only exception was that the first level of the NDP3 program, prespeech oral-motor skills, was omitted to ensure that the amount of verbal practice trials was consistent across the two treatments. Each participant had three individualized speech production treatment goals, selected using the “Treatment Planning and Progression” guidelines on the basis of the child's pretreatment assessment results (Williams & Stephens, 2004). Goals were selected to target unknown segments as single sounds or as syllable shapes using known sounds (see the Supplemental Appendix in the online supplemental materials for an example). Five individualized stimuli were selected to address each goal. Each goal was treated in a separate block of 18 min each session within a game-based activity. Participants were required to achieve 90% spontaneous accuracy for each target stimulus before moving on to different stimuli within the same goal. After five stimuli for a goal-reached criterion, the child stepped up to the next goal level in the NDP3 hierarchy. Verbal instructions, modeling, and articulation and visual-tactile cues were provided as needed throughout the session, and immediate KR and KP feedback was provided after every production attempt (i.e., 100% KR and KP feedback frequency). If a production was correct, the participant was asked to repeat the response three times, with KR and KP feedback given by the clinician.
Outcomes
Testing Schedule
Postevaluations were scheduled within 1 week (M = 3.5 days, SD = 1.6), 1 month (M = 31.96 days, SD = 2.3), and 4 months (M = 119.12 days, SD = 5.2) posttreatment.2  At each time point, the experimental probe and DEAP Inconsistency subtest were administered. The Single-Word Test of Polysyllables and GFTA-2 were administered pretreatment and 1 month posttreatment. All participants' caregivers reported no additional SLP intervention between study onset and 1-month posttreatment. Of the 26 participants, 18 (69%) resumed community SLP services between 1 and 4 months posttreatment: six from the ReST and eight from the NDP3 group received therapy at least once a week; three from the ReST and one from the NDP3 group had less frequent therapy.
Primary Outcome Measures
Primary outcomes were assessed using a purpose designed 292-item experimental probe. The probe consisted of treated and untreated stimuli: 162 items from the NDP3 assessment, 80 pseudowords for the ReST treatment, and 50 additional untreated one-, two-, and three-syllable real-word stimuli that were included to test for further generalization of treatment effects in both groups. Each child was assessed on individualized treated items. In the case of ReST, this included 20 treated stimuli at the child's current complexity level and 20 stimuli of the next level of complexity, determined prior to group allocation. Eleven participants commenced at the two-syllable level and 15 commenced at the three-syllable level. No participants commenced at carrier phrase level. The remaining untreated NDP3 and 50 additional items were used to determine generalization to real words. The remaining 40 ReST stimuli were used to determine generalization to pseudowords (novel words). All stimuli in the probe were adjusted to test for generalization to words of similar or lower complexity, on the basis of the individualized complexity of participants' treated items (Schneider & Frens, 2005). Table 3 details the complexity levels used to develop these individualized stimulus hierarchies.
Table 3. Levels of stimulus complexity guiding selection of treated items and comparable real-word items for measuring response generalization.
Levels of stimulus complexity guiding selection of treated items and comparable real-word items for measuring response generalization.×
Stimulus complexity Participant's treatment items (for allocated treatment) Participant's generalization items (for both treatments)
Untreated real-word items Untreated pseudoword items
Level 1 ReST • Consonants and vowels in isolation. • Two-syllable ReST stimulia (similar to NDP3 CVCV goal stimuli with known or highly stimulable sounds that were treated).
• Two-syllable stimuli (if stepped up to three-syllable stimuli, moved to Level 2). • One-syllable words (CV and CVC) from NDP3 stimuli and additional stimuli.
NDP3 • Two-syllable words (CVCV) from NDP3 stimuli and additional stimuli.a
• single sound, CV, VC, CVCV,a and CVC goals.
Level 2 ReST Level 1 items, plus • Three-syllable ReST stimulia (similar to NDP3 multisyllabic goal stimuli with known or highly stimulable sounds that were treated).
• Three-syllable stimulia (if stepped up to three-syllable stimuli in carrier phrases, moved to Level 3). • Three-syllable word from additional stimuli.a
NDP3 • Multisyllabic NDP3 stimuli.a
• Any two of single sound, CV, VC, CVCV,a CVC.
And multisyllabica words.
Level 3 ReST Level 1 and 2 items, plus • Three-syllable ReST stimuli (similar to NDP3 multisyllabic goal stimuli with known or highly stimulable sounds that were treated).
• Three-syllable stimuli.a • NDP3 clusters. • Three-syllable stimuli in carrier phrases (similar to NDP phrasal stimuli with known sounds).
• Three-syllable stimuli in carrier phrasesa (as stepped up in treatment). • NDP3 phrases.
NDP3
• Any two of single sound, CV, VC, CVCV,a CVC, multisyllabica words and clusters.
• And everyday phrases.a
a These stimuli were used to address or assess lexical/phrasal stress in addition to articulation. ReST = Rapid Syllable transition treatment; NDP3 = Nuffield Dyspraxia Programme–Third Edition.
These stimuli were used to address or assess lexical/phrasal stress in addition to articulation. ReST = Rapid Syllable transition treatment; NDP3 = Nuffield Dyspraxia Programme–Third Edition.×
Table 3. Levels of stimulus complexity guiding selection of treated items and comparable real-word items for measuring response generalization.
Levels of stimulus complexity guiding selection of treated items and comparable real-word items for measuring response generalization.×
Stimulus complexity Participant's treatment items (for allocated treatment) Participant's generalization items (for both treatments)
Untreated real-word items Untreated pseudoword items
Level 1 ReST • Consonants and vowels in isolation. • Two-syllable ReST stimulia (similar to NDP3 CVCV goal stimuli with known or highly stimulable sounds that were treated).
• Two-syllable stimuli (if stepped up to three-syllable stimuli, moved to Level 2). • One-syllable words (CV and CVC) from NDP3 stimuli and additional stimuli.
NDP3 • Two-syllable words (CVCV) from NDP3 stimuli and additional stimuli.a
• single sound, CV, VC, CVCV,a and CVC goals.
Level 2 ReST Level 1 items, plus • Three-syllable ReST stimulia (similar to NDP3 multisyllabic goal stimuli with known or highly stimulable sounds that were treated).
• Three-syllable stimulia (if stepped up to three-syllable stimuli in carrier phrases, moved to Level 3). • Three-syllable word from additional stimuli.a
NDP3 • Multisyllabic NDP3 stimuli.a
• Any two of single sound, CV, VC, CVCV,a CVC.
And multisyllabica words.
Level 3 ReST Level 1 and 2 items, plus • Three-syllable ReST stimuli (similar to NDP3 multisyllabic goal stimuli with known or highly stimulable sounds that were treated).
• Three-syllable stimuli.a • NDP3 clusters. • Three-syllable stimuli in carrier phrases (similar to NDP phrasal stimuli with known sounds).
• Three-syllable stimuli in carrier phrasesa (as stepped up in treatment). • NDP3 phrases.
NDP3
• Any two of single sound, CV, VC, CVCV,a CVC, multisyllabica words and clusters.
• And everyday phrases.a
a These stimuli were used to address or assess lexical/phrasal stress in addition to articulation. ReST = Rapid Syllable transition treatment; NDP3 = Nuffield Dyspraxia Programme–Third Edition.
These stimuli were used to address or assess lexical/phrasal stress in addition to articulation. ReST = Rapid Syllable transition treatment; NDP3 = Nuffield Dyspraxia Programme–Third Edition.×
×
Primary outcomes were (a) treatment gains, (b) maintenance of treatment gains for treated items, and (c) expected response generalization to untreated real words and pseudowords using experimental probe items at the child's generalization level as is consistent with the aims and hypotheses. The primary dependent variable was percent accuracy of responses for treated and untreated stimuli on the probe perceptually judged correct at the whole-word level (with simultaneous articulatory and prosodic accuracy).
Counts of correct productions were completed, with each whole word production coded as 1 if: (a) all phonemes produced accurately (including with no phonetic distortion), (b) smooth transitions across sounds and syllables (i.e., no syllable segregation, hesitations, or within-speech groping noted), and (c) accurate lexical stress production of each syllable (e.g., clear and appropriate strong–weak, weak–strong, or strong–strong stress) for all two-syllable real- and pseudoword items. If any error was noted in segments, transitions and/or prosody an item was coded as incorrect (given a score of 0). For phrase-level stimuli, each word in the phrase was scored separately. This accuracy criterion covered the three core consensus-based features of CAS (ASHA, 2007). Percent accuracy was determined by calculating the number of correct productions over attempts multiplied by 100. Participants were not penalized for age-appropriate developmental phonological errors (such as gliding /r/ to /w/).
Secondary Outcome Measures
Several secondary measures of generalization were made to further explore potential differences in the treatments' effects. Imitated word accuracy in untreated connected speech of at least three word combinations (as defined by the NDP3 manual, Williams & Stephens, 2004, p. 143) were analyzed using probed untreated NDP3 assessment connected speech stimuli to determine whether treatment for all participants within each group resulted in more accurate connected speech production. The DEAP Inconsistency subtest was readministered to identify any changes in lexical token-to-token inconsistency, considered a core feature of CAS (ASHA, 2007). A decrease in this score indicates reduced inconsistency. Then, both the Single-Word Test of Polysyllables and the GFTA-2 were readministered at 1-month posttreatment to document any changes in segmental accuracy using percent phonemes correct (PPC), percent vowels correct (PVC), and percent consonants correct (PCC), as well as percent lexical stress (prosodic) matches for untreated single words in clinically available assessments. These measures were obtained by assessors transcribing the participants' responses to the test and entering the transcription data into the PROPH module of Computerized Profiling (Long, Fey, & Channell, 2006). PROPH was used to quantify these measures to obtain a percent of accurate productions over attempts for each measure. An increase in any of these measures is seen as improvement in segmental (PPC, PVC, and PCC) or prosodic (percent lexical stress matches) accuracy.
Recording, Fidelity, and Reliability
Every treatment session was video- and audio-recorded using the Cinde 88 audiovisual system (Cinde, Melbourne, Australia) and Sony ICD-UX71F (Sony, Tokyo, Japan) or similar audio recorder for later calculation of treatment fidelity and inter- and intrarater reliability on dependent variables. All testing sessions were additionally audio-recorded using professional digital recorders (Echo Layla 24/96 multitrack recording system [Echo, Santa Barbara, CA], Marantz PMD660 solid-state recorder [Marantz, Eindhoven, the Netherlands], or a Roland Quad-Capture UA-55 [Roland, Los Angeles, CA]) utilizing a child-sized headset microphone (AKG C520, AKG Acoustics, Vienna, Austria) with 5-cm mouth-to-microphone distance.
Treatment fidelity was calculated for 10% of every treatment session between the first author and student clinicians for application of the cues, feedback, and repetitions in the operationalized protocol. The protocol was followed on average 93% of the time (SD = 4.3) across all treatment sessions.
Reliability on judgments of correct/incorrect responses during treatment sessions was calculated for 10% of all sessions. Mean intrarater reliability for articulation was 99% (SD = 0.4) and for prosody 92% (SD = 2.6) and interrater reliability for articulation was 99% (SD = 0.9) and for prosody 89% (SD = 3.8).
Point-by-point phonetic transcription reliability on responses during the experimental probes (broad transcription supplemented with diacritics for any phonetic distortion errors made) was calculated for 10% of responses in each pre- and posttreatment probe. Mean intrarater reliability was 97% (SD = 3.2) for the first author's transcription of pretreatment assessments and 95% (SD = 3.9) for outcome assessors' transcription of posttreatment assessments. Interrater reliability between outcome assessors and a research assistant for posttreatment assessments was 93% (SD = 4.3). Mean interrater reliability on judgments of correct/incorrect productions requiring correct articulation of segments, co-articulation, and prosody was 98% (SD = 1.2).
Point-by-point transcription accuracy was also calculated for 10% of each administration of the secondary outcomes. This included broad transcription on the DEAP Inconsistency subtest, and phonetic transcription (with diacritics for errors only) on the GFTA-2 and Single-Word Test of Polysyllables. Mean intrarater reliability was 98% (SD = 1.7) and interrater reliability was 94% (SD = 3.7).
Statistical Analysis
One participant withdrew from the NDP3 treatment prior to posttreatment probes, and therefore, an intention-to-treat analysis was utilized. There are four possible methodologies for intention-to-treat (The Cochrane Collaboration, 2002). All four were tested with no influence on the results; therefore, the mean of the NDP3 group's data was used for this participant for each posttreatment assessment.
Three planned comparisons for each primary and secondary outcome measure were used to address the study aims and hypotheses: (1) pretreatment versus within 1-week posttreatment to assess acquisition of treatment and generalization effects, (2) 1-week versus 1-month posttreatment to assess short-term maintenance of these effects, and (3) 1-week versus 4-months posttreatment to test longer-term maintenance as per Field (2013) . The exception to this was the Single-Word Test of Polysyllables and GFTA-2, which were administered on only two occasions—pretreatment and 1-month posttreatment. For each planned comparison, the within-subjects variables were based on time (e.g., treated items at pre- and 1-week posttreatment) and between-subjects variable was treatment (ReST or NDP3), giving results for each type of variable and the interaction between them (Time × Group). Repeated measures analysis of variance (ANOVA) with 95% confidence intervals and alpha set at .05 were run in IBM SPSS Statistics 21 for Windows (Field, 2013), with any assumption violations addressed statistically beforehand. For statistically significant comparisons, Cohen's d effect sizes were calculated (Cohen, 1988).
To further ensure that any significant results reflected real change, the influence of age and severity (i.e., PCC from the Single-Word Test of Polysyllables and standard score from the GFTA-2 as general measures) on all the outcome measures, as well as the influence of age on severity, were explored with correlation analyses. There was no significant correlation for severity or age and severity. Age was significantly correlated with the outcome measure PCC on the Single-Word Test of Polysyllables (r = .602, p < .001) for both groups, and with accuracy on treated items from the probe at 1-week posttreatment for the ReST group (r = .558, p = .048). Therefore, age was entered as a covariate in the analyses containing data from the Single-Word Test of Polysyllables or treated items on the probe (ANCOVA).
Results
Primary Outcomes
Means and standard deviations for all measures at all four time points are reported in Table 4. The results of the ANOVA and ANCOVA comparisons are reported in Table 5.
Table 4. Means (standard deviations) for treatment and generalization measures.
Means (standard deviations) for treatment and generalization measures.×
Treatment group Pretreatment
1-week posttreatment
1-month posttreatment
4-months posttreatment
ReST NDP3 ReST NDP3 ReST NDP3 ReST NDP3
Primary outcomes
 Accuracy on items treated 10.8 (8.6) 30.3 (20.3) 34.8 (24.4) 70.1 (16.3) 44.7 (22.8) 66.3 (20.4) 45.0 (19.4)a 60.2 (12.2)
 Accuracy on items expected to generalize
  Untreated real-words 44.0 (13.7) 45.7 (15.1) 58.1 (19.2) 56.7 (18.5) 62.3 (19.9) 63.9 (20.9) 62.0 (17.9) 66.5 (16.2)
  Untreated pseudowords 8.5 (9.7) 11.1 (9.1) 29.6 (19.4) 16.2 (20.7) 37.5 (24.8) 33.9 (30.3) 38.8 (17.5) 31.4 (25.5)
Secondary measures
 Connected speech (imitation accuracy in >three word combinations) 35.2 (24.1) 29.8 (22.9) 44.8 (28.6) 42.8 (26.2) 46.7 (19.5) 44.1 (24.0) 50.7 (20.2) 49.4 (26.7)
 DEAP Inconsistency 61.4 (12.6) 65.8 (12.3) 48.5 (16.3) 47.5 (19.3) 50.5 (21.3) 54.7 (18.9) 56.3 (13.7) 52.5 (28.4)
 Single-Word Test of Polysyllables
  PPC 53.9 (14.5) 50.5 (16.7) 63.5 (17.9) 57.5 (20.2)
  PVC 51.7 (10.4) 50.1 (13.1) 70.2 (14.8) 62.0 (16.7)
  PCC 56.2 (19.8) 51.0 (21.7) 56.8 (22.9) 52.9 (27.2)
  Percent lexical stress matches 10.8 (7.4) 9.1 (11.3) 44.4 (25.9) 33.1 (20.5)
 GFTA-2
  PPC 62.0 (19.5) 63.8 (13.5) 75.8 (15.6) 66.8 (27.5)
  PVC 71.3 (12.9) 66.3 (14.8) 85.5 (10.8) 83.3 (12.8)
  PCC 57.1 (21.8) 56.5 (22.4) 66.1 (21.0) 61.5 (28.6)
  Percent lexical stress matches 69.2 (19.8) 56.9 (21.4) 87.9 (9.6) 85.3 (12.2)
a Indicates treated pseudowords; — = not assessed. ReST = Rapid Syllable Transition treatment; NDP3 = Nuffield Dyspraxia Programme–Third Edition; DEAP Inconsistency = Diagnostic Evaluation of Articulation and Phonology Inconsistency test; PPC = percent phonemes correct; PVC = percent vowels correct; PCC = percent consonants correct; GFTA-2 = Goldman-Fristoe Test of Articulation–Second Edition.
Indicates treated pseudowords; — = not assessed. ReST = Rapid Syllable Transition treatment; NDP3 = Nuffield Dyspraxia Programme–Third Edition; DEAP Inconsistency = Diagnostic Evaluation of Articulation and Phonology Inconsistency test; PPC = percent phonemes correct; PVC = percent vowels correct; PCC = percent consonants correct; GFTA-2 = Goldman-Fristoe Test of Articulation–Second Edition.×
Table 4. Means (standard deviations) for treatment and generalization measures.
Means (standard deviations) for treatment and generalization measures.×
Treatment group Pretreatment
1-week posttreatment
1-month posttreatment
4-months posttreatment
ReST NDP3 ReST NDP3 ReST NDP3 ReST NDP3
Primary outcomes
 Accuracy on items treated 10.8 (8.6) 30.3 (20.3) 34.8 (24.4) 70.1 (16.3) 44.7 (22.8) 66.3 (20.4) 45.0 (19.4)a 60.2 (12.2)
 Accuracy on items expected to generalize
  Untreated real-words 44.0 (13.7) 45.7 (15.1) 58.1 (19.2) 56.7 (18.5) 62.3 (19.9) 63.9 (20.9) 62.0 (17.9) 66.5 (16.2)
  Untreated pseudowords 8.5 (9.7) 11.1 (9.1) 29.6 (19.4) 16.2 (20.7) 37.5 (24.8) 33.9 (30.3) 38.8 (17.5) 31.4 (25.5)
Secondary measures
 Connected speech (imitation accuracy in >three word combinations) 35.2 (24.1) 29.8 (22.9) 44.8 (28.6) 42.8 (26.2) 46.7 (19.5) 44.1 (24.0) 50.7 (20.2) 49.4 (26.7)
 DEAP Inconsistency 61.4 (12.6) 65.8 (12.3) 48.5 (16.3) 47.5 (19.3) 50.5 (21.3) 54.7 (18.9) 56.3 (13.7) 52.5 (28.4)
 Single-Word Test of Polysyllables
  PPC 53.9 (14.5) 50.5 (16.7) 63.5 (17.9) 57.5 (20.2)
  PVC 51.7 (10.4) 50.1 (13.1) 70.2 (14.8) 62.0 (16.7)
  PCC 56.2 (19.8) 51.0 (21.7) 56.8 (22.9) 52.9 (27.2)
  Percent lexical stress matches 10.8 (7.4) 9.1 (11.3) 44.4 (25.9) 33.1 (20.5)
 GFTA-2
  PPC 62.0 (19.5) 63.8 (13.5) 75.8 (15.6) 66.8 (27.5)
  PVC 71.3 (12.9) 66.3 (14.8) 85.5 (10.8) 83.3 (12.8)
  PCC 57.1 (21.8) 56.5 (22.4) 66.1 (21.0) 61.5 (28.6)
  Percent lexical stress matches 69.2 (19.8) 56.9 (21.4) 87.9 (9.6) 85.3 (12.2)
a Indicates treated pseudowords; — = not assessed. ReST = Rapid Syllable Transition treatment; NDP3 = Nuffield Dyspraxia Programme–Third Edition; DEAP Inconsistency = Diagnostic Evaluation of Articulation and Phonology Inconsistency test; PPC = percent phonemes correct; PVC = percent vowels correct; PCC = percent consonants correct; GFTA-2 = Goldman-Fristoe Test of Articulation–Second Edition.
Indicates treated pseudowords; — = not assessed. ReST = Rapid Syllable Transition treatment; NDP3 = Nuffield Dyspraxia Programme–Third Edition; DEAP Inconsistency = Diagnostic Evaluation of Articulation and Phonology Inconsistency test; PPC = percent phonemes correct; PVC = percent vowels correct; PCC = percent consonants correct; GFTA-2 = Goldman-Fristoe Test of Articulation–Second Edition.×
×
Table 5. ANOVA and ANCOVA comparisons for outcomes measured at all time points.
ANOVA and ANCOVA comparisons for outcomes measured at all time points.×
Statistical comparisons Pretreatment to 1-week posttreatment
1-week to 1-month posttreatment
1-week to 4-months posttreatment
Time Group Time × Group Time Group Time × Group Time Group Time × Group
Primary Outcomes
 Accuracy on items treateda F = 5.92* F = 40.81** F = 4.28* F = 3.48 F = 23.85** F = 4.48* F = 6.79* F = 26.31** F = 9.52**
(NDP3 ) (NDP3 ) (ReST ) (ReST ) (ReST ) (ReST )
 Accuracy on items expected to generalize
  Untreated real words F = 40.747** F = 0.064 F = 0.006 F = 6.512* F < 0.001 F = 0.549 F = 6.201* F = 0.055 F = 1.155
  Untreated pseudowords F = 14.997* F = 1.132 F = 5.634* F =11.734** F = 0.952 F = 1.799 F = 9.757** F = 1.275 F = 2.382
(ReST )
Secondary Outcomes
 Connected speech (imitation of > three word combinations) F = 28.401** F = 0.129 F = 0.628 F = 0.268 F = 0.057 F = 0.012 F = 3.459 F = 0.026 F = 0.009
 DEAP Inconsistency F = 54.166** F = 0.102 F = 1.572 F = 1.650 F = 0.015 F = 0.355 F = 2.379 F = 0.120 F = 0.136
Note. df(1, 25) for all comparisons.
Note. df(1, 25) for all comparisons.×
a ANCOVA used.
ANCOVA used.×
* p = .05,
p = .05,×
** p = .01.
p = .01.×
= better performance.
= better performance.×
Table 5. ANOVA and ANCOVA comparisons for outcomes measured at all time points.
ANOVA and ANCOVA comparisons for outcomes measured at all time points.×
Statistical comparisons Pretreatment to 1-week posttreatment
1-week to 1-month posttreatment
1-week to 4-months posttreatment
Time Group Time × Group Time Group Time × Group Time Group Time × Group
Primary Outcomes
 Accuracy on items treateda F = 5.92* F = 40.81** F = 4.28* F = 3.48 F = 23.85** F = 4.48* F = 6.79* F = 26.31** F = 9.52**
(NDP3 ) (NDP3 ) (ReST ) (ReST ) (ReST ) (ReST )
 Accuracy on items expected to generalize
  Untreated real words F = 40.747** F = 0.064 F = 0.006 F = 6.512* F < 0.001 F = 0.549 F = 6.201* F = 0.055 F = 1.155
  Untreated pseudowords F = 14.997* F = 1.132 F = 5.634* F =11.734** F = 0.952 F = 1.799 F = 9.757** F = 1.275 F = 2.382
(ReST )
Secondary Outcomes
 Connected speech (imitation of > three word combinations) F = 28.401** F = 0.129 F = 0.628 F = 0.268 F = 0.057 F = 0.012 F = 3.459 F = 0.026 F = 0.009
 DEAP Inconsistency F = 54.166** F = 0.102 F = 1.572 F = 1.650 F = 0.015 F = 0.355 F = 2.379 F = 0.120 F = 0.136
Note. df(1, 25) for all comparisons.
Note. df(1, 25) for all comparisons.×
a ANCOVA used.
ANCOVA used.×
* p = .05,
p = .05,×
** p = .01.
p = .01.×
= better performance.
= better performance.×
×
Treatment Effects
Performance on the treated stimuli for the two groups is graphed in Figure 2 and was calculated using ANCOVAs. In comparisons of performance on treated items from pretreatment to 1-week posttreatment, the main effects of time and group as well as the interaction effect were significant. That is, although both groups demonstrated significantly increased accuracy over time, the NDP3 group made greater gains in accuracy than the ReST group. Both treatments demonstrated a large effect size: NDP3 (d = 2.162) and ReST (d = 1.312).
Figure 2.

Percent change in accuracy of production for treated items from pretreatment to 4-months posttreatment on the experimental probes. Pretreatment performance is normalized to zero due to the different stimuli used across treatments and the lack of significant differences at pretreatment between groups. Error bars represent 95% confidence intervals. The main effect of time and group and the interaction effect of time by group are significant, favoring NDP3 at pre- to 1-week posttreatment and favoring ReST at 1-week to 1-month and 4-months posttreatment.

 Percent change in accuracy of production for treated items from pretreatment to 4-months posttreatment on the experimental probes. Pretreatment performance is normalized to zero due to the different stimuli used across treatments and the lack of significant differences at pretreatment between groups. Error bars represent 95% confidence intervals. The main effect of time and group and the interaction effect of time by group are significant, favoring NDP3 at pre- to 1-week posttreatment and favoring ReST at 1-week to 1-month and 4-months posttreatment.
Figure 2.

Percent change in accuracy of production for treated items from pretreatment to 4-months posttreatment on the experimental probes. Pretreatment performance is normalized to zero due to the different stimuli used across treatments and the lack of significant differences at pretreatment between groups. Error bars represent 95% confidence intervals. The main effect of time and group and the interaction effect of time by group are significant, favoring NDP3 at pre- to 1-week posttreatment and favoring ReST at 1-week to 1-month and 4-months posttreatment.

×
Maintenance of Treatment Effects
Between 1-week and 1-month posttreatment, the main effect of time was not significant, but a significant group and interaction effect indicated that whereas the ReST group made a small increase in accuracy on treated items over this month (d = 0.420), the NDP3 demonstrated a small decrease in accuracy (d = −0.206). Also, from 1-week to 4-months posttreatment, there was a significant group and interaction effect, with the ReST group again showing a small increase in accuracy on treated items (d = 0.463), whereas the NDP3 group showed a moderate decrease in accuracy (d = −0.688).
Generalization of Treatment Effects to Real Words
Performance on the untreated real-word stimuli expected to demonstrate generalization is graphed in Figure 3. There was a significant main effect for time only, with both groups significantly increasing accuracy of real-word production at all three time points. Gains were moderate from pretreatment to 1-week posttreatment (d = 0.744) and small from 1-week posttreatment to both 1-month (d = 0.290) and 4-months (d = 0.250) posttreatment.
Figure 3.

Accuracy of production for untreated real words from pretreatment to 4 months posttreatment on the experimental probes. Treatment effects were predicted to generalize to untreated real words at each child's generalization level. The main effect of time is significant for both groups from pretreatment to 1 week posttreatment and from 1 week posttreatment to both 1 month and 4 posttreatment.

 Accuracy of production for untreated real words from pretreatment to 4 months posttreatment on the experimental probes. Treatment effects were predicted to generalize to untreated real words at each child's generalization level. The main effect of time is significant for both groups from pretreatment to 1 week posttreatment and from 1 week posttreatment to both 1 month and 4 posttreatment.
Figure 3.

Accuracy of production for untreated real words from pretreatment to 4 months posttreatment on the experimental probes. Treatment effects were predicted to generalize to untreated real words at each child's generalization level. The main effect of time is significant for both groups from pretreatment to 1 week posttreatment and from 1 week posttreatment to both 1 month and 4 posttreatment.

×
Generalization of Treatment Effects to Untreated Pseudowords
Performance on the untreated pseudoword stimuli for the two groups is graphed in Figure 4. Although the untreated pseudowords were untreated ReST stimuli, all children who received the NDP3 were treated on similar structures and sounds to reduce stimuli effects (see Table 3 for more detail). From pretreatment to 1-week posttreatment, there was a significant main effect of time and an interaction effect, with the ReST group demonstrating a large increase in accuracy (d = 1.376) and the NDP3 group showing a small increase in accuracy of untreated related pseudowords (d = 0.319).
Figure 4.

Accuracy of production for untreated pseudowords from pretreatment to 4-months posttreatment on the experimental probes for the ReST and NDP3 groups. Treatment effects were predicted to generalize to untreated pseudowords at each child's generalization level. The main effect of time is significant from pretreatment to 1-week posttreatment and from 1-week to both 1-month and 4-months posttreatment. There is a significant interaction effect favoring ReST from pretreatment to 1-week posttreatment.

 Accuracy of production for untreated pseudowords from pretreatment to 4-months posttreatment on the experimental probes for the ReST and NDP3 groups. Treatment effects were predicted to generalize to untreated pseudowords at each child's generalization level. The main effect of time is significant from pretreatment to 1-week posttreatment and from 1-week to both 1-month and 4-months posttreatment. There is a significant interaction effect favoring ReST from pretreatment to 1-week posttreatment.
Figure 4.

Accuracy of production for untreated pseudowords from pretreatment to 4-months posttreatment on the experimental probes for the ReST and NDP3 groups. Treatment effects were predicted to generalize to untreated pseudowords at each child's generalization level. The main effect of time is significant from pretreatment to 1-week posttreatment and from 1-week to both 1-month and 4-months posttreatment. There is a significant interaction effect favoring ReST from pretreatment to 1-week posttreatment.

×
From 1-week posttreatment to both 1-month and 4-months posttreatment, there was a significant effect of time but no main effect of group and no Group × Time interaction. The groups combined made moderate increases in accuracy from 1-week to 1-month and 4-months posttreatment (d = 0.530 and d = 0.586, respectively).
Secondary Outcome Measures: Generalization of Treatment Effects
For connected speech, (as measured by imitated word accuracy in phrases of at least three words up to nine words) within the experimental probe, there was no effect of group. There was a significant but small increase in accuracy from pretreatment to 1-week posttreatment for both groups (d = 0.443). This increase was maintained to 4-months posttreatment, with no further significant change noted.
For inconsistency of repeated productions of untreated real words, as measured by the DEAP Inconsistency subtest, there was a significant and large decrease in inconsistency from pretreatment to 1-week posttreatment (d = 1.014) for both groups (see Table 5). No further change was evident (i.e., the original gain was maintained) from 1-week to 1-month or 4-months posttreatment.
Statistical comparisons for outcome measures from the Single-Word Test of Polysyllables and GFTA-2 are reported in Table 6. The Single-Word Test of Polysyllables used an ANCOVA. Across all four measures (PPC, PVC, PCC, and percent lexical stress matches), there were no group or interaction effects in either test. However, for the Single-Word Test of Polysyllables, there was a large and significant main effect of time (pretreatment to 1-month posttreatment) on PVC and percent lexical stress matches in (PVC: d = 1.090, percent lexical stress matches: d = 1.627). This indicates both treatments increased vowel and lexical stress accuracy to 1-month posttreatment. For the GFTA-2, there were significant changes over time for PPC, PVC, PCC, and percent lexical stress matches. PVC showed a large increase in vowel accuracy (d = 0.805), percent lexical stress matched a moderate increase in using correct syllable stress within words (d = 0.713), and PPC and PCC showed small increases in using phonemes and consonants accurately (d = 0.438 and d = 0.298, respectively).
Table 6. Statistical comparisons for Single-Word Test of Polysyllables and Goldman-Fristoe Test of Articulation–Second Edition (GFTA-2).
Statistical comparisons for Single-Word Test of Polysyllables and Goldman-Fristoe Test of Articulation–Second Edition (GFTA-2).×
Measure Pretreatment to 1-month posttreatment
Time Group Time × Group
Single-Word Test of Polysyllablesa
 PPC F = 2.896 F = 0.044 F = 0.458
 PVC F = 6.053* F = 0.319 F = 2.033
 PCC F = 0.545 F = 0.001 F = 0.017
 Percent lexical stress matches F = 5.507* F = 0.480 F = 1.246
GFTA-2
 PPC F = 29.207** F = 0.016 F = 1.593
 PVC F = 73.648** F = 0.596 F = 0.592
 PCC F = 7.742** F = 0.870 F = 0.616
 Percent lexical stress matches F = 39.735** F = 2.008 F = 1.691
Note. df(1, 25) for all comparisons;
Note. df(1, 25) for all comparisons;×
a ANCOVA used;
ANCOVA used;×
* p = .05;
p = .05;×
** p = .01.
p = .01.×
Table 6. Statistical comparisons for Single-Word Test of Polysyllables and Goldman-Fristoe Test of Articulation–Second Edition (GFTA-2).
Statistical comparisons for Single-Word Test of Polysyllables and Goldman-Fristoe Test of Articulation–Second Edition (GFTA-2).×
Measure Pretreatment to 1-month posttreatment
Time Group Time × Group
Single-Word Test of Polysyllablesa
 PPC F = 2.896 F = 0.044 F = 0.458
 PVC F = 6.053* F = 0.319 F = 2.033
 PCC F = 0.545 F = 0.001 F = 0.017
 Percent lexical stress matches F = 5.507* F = 0.480 F = 1.246
GFTA-2
 PPC F = 29.207** F = 0.016 F = 1.593
 PVC F = 73.648** F = 0.596 F = 0.592
 PCC F = 7.742** F = 0.870 F = 0.616
 Percent lexical stress matches F = 39.735** F = 2.008 F = 1.691
Note. df(1, 25) for all comparisons;
Note. df(1, 25) for all comparisons;×
a ANCOVA used;
ANCOVA used;×
* p = .05;
p = .05;×
** p = .01.
p = .01.×
×
Discussion
This clinical trial compared the efficacy of the ReST and NDP3 motor treatments for two groups of 13 children aged between 4 and 12 years with CAS. We hypothesized that both treatments would generate a similar degree of change in treated behaviors from pretreatment to within 1-week posttreatment. We also predicted that ReST treatment would result in greater maintenance and generalization of treatment effects than NDP3 at 1-month and 4-months posttreatment, due to incorporation of facilitative PML, use of pseudowords, and high target complexity to addressing a range of underlying motor patterns.
Contrary to our first hypothesis, the NDP3 group demonstrated significantly greater accuracy on treatment items than the ReST group between pretreatment and 1-week posttreatment. Our initial hypothesis of both treatments making similar gains was based on high treatment intensity and addressing the three consensus-based features of CAS (ASHA, 2007). However, the stronger acquisition resulting from NDP3 treatment is consistent with studies of motor learning principles where use of 100% KP and KR feedback tends to facilitate greater acquisition in the short term (e.g., Bruechert, Lai, & Shea, 2003; Winstein & Schmidt, 1990). The participants in the NDP3 group received specific feedback and cuing after every production, which facilitated correct production on subsequent trials.
Results were consistent with our second hypothesis, with the children receiving ReST treatment showing strong maintenance of treatment gains up to 1- and 4-months posttreatment. This may be attributed to the use of specific PML during practice, principles that are known to facilitate long-term maintenance, such as low frequency, delayed KR feedback (Austermann Hula, Robin, Maas, Ballard, & Schmidt, 2008; Maas, Butalla, & Farinella, 2012) and random order of stimulus presentation (Knock, Ballard, Robin, & Schmidt, 2000; but see Maas & Farinella, 2012). In contrast, the NDP3 is not divided into distinct prepractice and practice phases and applies principles that are associated with facilitating acquisition rather than maintenance of skills. Children receiving NDP3 treatment showed a decrease in accuracy on treated items over time after treatment was withdrawn. This suggests that the participants who received the NDP3 may have relied on the treatment cues and feedback to maintain their abilities. In contrast, the participants in the ReST group not only maintained but also increased their accuracy of treated items up to 4-months posttreatment, suggesting improved motor learning. With the better acquisition in the NDP3 group and stronger maintenance in the ReST group, performance across the two groups was similar at 4-months posttreatment (see Figure 2). We did not test the NDP3 group's performance past 4-months posttreatment, and suggest that future studies could investigate whether maintenance would improve if the protocol were modified to incorporate practice phase PML known to facilitate maintenance.
Our final hypothesis, that the ReST group would generalize the effects of treatment to untreated primary outcomes more than the NDP3 group, was partially supported. Although the ReST group showed stronger generalization than the NDP3 group for untreated pseudowords, the two groups improved similarly for untreated real words. The ReST treatment may have demonstrated more effective generalization to novel stimuli due to the training of complex stimuli that included explicit training of syllable sequences in the context of reduced frequency and delayed KR feedback. Higher target complexity has been shown to generalize to lower target complexity (Maas et al., 2002; Schneider & Frens, 2005) and pseudowords to generalize to real words without having to address learned erroneous forms (Gierut et al., 2010). As such, ReST may have facilitated greater flexibility in learning and assisted the children to build internal representations of accuracy, leading to greater generalization. In contrast, the NDP3 uses a lower stimulus complexity and real words, and erroneous productions are broken down to smaller units (e.g., /pi/ to /p/ and /i/) to rebuild again, a process that may reduce generalization effects in a context of acquisition-based PML.
Despite the differences discussed above, both treatments provided intensive practice of a wide range of motor patterns targeted across diverse stimuli with variable practice. Practice across a variety of motor patterns appears crucial, as the motor learning literature suggests that generalization is heavily influenced by varying phonetic and timing patterns. For example, both ReST and NDP3 directly targeted (a) speech sounds of different manner classes, a beneficial procedure given that treatment effects tend not to generalize across class (Ballard, 2001; Ballard, Maas, & Robin, 2007; Knock et al., 2000; Wambaugh, 2004); (b) strong–weak and weak–strong stress patterns, with evidence that training one stress pattern does not to generalize to other stress combinations due to the different relative timing patterns (Maas et al., 2012; Maas & Farinella, 2012; Sakai, Kitaguchi, & Hikosaka, 2003); and (c) sequencing of segments and syllables that require different motor planning processing (Bohland & Guenther, 2006). Furthermore, both treatments effected change in segmental, co-articulation, and prosodic accuracy, as well as a reduction in inconsistency, demonstrating change across the three core consensus-based features of CAS (ASHA, 2007). The above discussion is largely theoretical and it is unclear exactly which ingredients led to the change seen here, as the treatments varied across several dimensions. PML only partially explains the results of this RCT as according to our original hypotheses; we expected ReST would perform better than the NDP3 across maintenance and generalization in all items. Some PML may be more crucial than others and individuals may respond differently (Maas et al, 2012; Maas & Farinella, 2012). More controlled comparative research into specific PML is needed to learn more about effecting generalization gains for each treatment.
ReST
The treatment and generalization results of ReST demonstrated a steady improvement and maintenance until 4-months posttreatment. These results are largely consistent with perceptual data from previous Phase I and Phase II studies (Ballard et al., 2010; McCabe et al., 2014; Staples et al., 2008), with the present study demonstrating greater treatment and maintenance of treatment effects (cf. Staples et al., 2008) and significant generalization to real-word stimuli (cf. Ballard et al., 2010). This difference could be attributed to many factors that would require more research to confirm, but could include the high phonotactic probability and orthographic bias of the stimuli used in the present study, the larger sample of real words probed here, or client factors (e.g., the three participants in Ballard et al., 2010, had only residual articulation errors).
The connected speech accuracy (of imitated word combinations of three or more words) found in this study indicates a similar pattern of generalization to connected speech probes as that reported by Staples et al. (2008)  and McCabe et al. (2010). The similar results may be due to consistent intensity and application of PML across the studies.
This study did not utilize acoustic measures of speech production. Ballard et al. (2010)  demonstrated that acoustic and perceptual measures of prosody were significantly correlated. We retained perceptual measures, as they are the standard for current clinical practice, and with rigorous clinician training, we ensured high interrater reliability. Acoustic measures may, however, be useful in future studies as they can be more objective and precise indices of change in specific speech behaviors such as lexical stress (Ballard et al., 2010; Ballard, Djaja, Arciuli, James, & van Doorn, 2012). Automated acoustic measures are currently being developed (e.g., Shahin, Ahmed, Ballard, McKechnie, & Murray, 2012).
NDP3
This is the first peer-reviewed published study to demonstrate effects for the NDP3. The NDP3 results here demonstrated stronger treatment and generalization effects than reported in previous unpublished studies that also used the NDP3 as per the manual and participants who had similar client characteristics to those in this study (Belton, 2006; Pagnamenta & Williams, 2009). Likewise, the NDP3 results in this RCT are superior to those in which some changes were made to the procedures in the manual (Teal, 2005; Watson & Gillon, 1999). This is likely due to reduced stimuli targeted in such studies (e.g. /k/ productions only in Teal, 2005) and thus not training across speech motor patterns to elicit as much generalization. Another fundamental difference is likely to be a higher intensity, with the previous studies being conducted in 1-hr weekly sessions for 20 sessions. The results suggest that use of the NDP3 program according to the manual is efficacious (when excluding nonspeech oral-motor targets), and that implementation in clinical practice may need to closely follow the manualized instructions.
Experimental studies of the NDP3 have not tested the nonspeech oral-motor treatment aspects of the program. It is currently recommended that such exercises not be used when treating CAS or other speech sound disorders, due to the limited similarity of prespeech oral-motor training to movement patterns used in speech and their low level of complexity (e.g., Forrest & Iuzzini, 2008; Lass & Pannbacker, 2008; McCauley, Strand, Lof, Schooling, & Frymark, 2009). The NDP3 program might be optimized by the inclusion of PML designed to facilitate maintenance and generalization including increasing stimulus complexity (e.g., omitting single-sound work), but further research is needed. This may facilitate greater maintenance and generalization effects as is seen in ReST.
Comparison with Other CAS Treatments
The Cohen's d effect sizes computed in this RCT (statistically equivalent to R2; Rosenthal, 1991) can be compared with Improvement Rate Difference computed in Murray et al. (2014)  as they are moderately highly correlated (Parker, Vannest, & Brown, 2009). The effect sizes for ReST and NDP3 in the present study appear greater than the moderate overall effect sizes reported by Murray et al. (2014)  for other CAS treatment approaches with multiple cases, such as Dynamic Temporal and Tactile Cueing (DTTC; e.g., Edeal & Gildersleeve-Neumann, 2011; Maas et al., 2012; Maas & Farinella, 2012; Strand & Debertine, 2000) and Integrated Phonological Awareness intervention (e.g., McNeill, Gillon, & Dodd, 2009; Moriarty & Gillon, 2006). The increased effect sizes may be due to ReST and the NDP3 treating simultaneous articulation and prosodic accuracy, with prosodic accuracy likely to have increased the effect sizes in this RCT as supported by greater improvement on lexical stress and vowel accuracy (PVC) than consonants on the GFTA-2 and Single-Word Test of Polysyllables.
In terms of generalization of ReST and NDP3 treatment effects, a range of measures was applied to permit some cautious comparison with previous studies. Greater effect sizes for generalization were seen for both the ReST and NDP3 groups than have previously been observed for DTTC (Edeal & Gildersleeve-Neumann, 2011; Maas et al., 2012; Maas & Farinella, 2012), most likely due to this study's simultaneous targeting of a wider range of motor patterns including prosody. However, for Integrated Phonological Awareness intervention, the effect sizes for PPC were larger (McNeill et al., 2009) than our relatively small effect size for PPC derived from the GFTA-2. This could again be due to the focus on articulation accuracy and the use of monosyllabic stimuli in the Integrated Phonological Awareness Intervention, compared with the simultaneous focus in the present study on articulation, co-articulation, and prosody for both mono- and polysyllabic words.
Other factors might have influenced comparison of the results of the present study to those of previous DTTC and Integrated Phonological Awareness intervention studies. High treatment intensity seemed to be a major factor in the results of the present study. Most DTTC (Edeal & Gildersleeve-Neumann, 2011; Maas et al., 2012; Maas & Farinella, 2012) and Integrated Phonological Awareness intervention studies were delivered at a slightly lower intensity of two to three sessions per week despite a similar overall number of sessions. This may also explain why the present treatment results are superior. Also furthering the argument for increased treatment intensity, the single participant treated with DTTC in Strand and Debertine (2000)  had more intense treatment than this RCT delivered—twice a day sessions—and obtained a very large effect size calculated using Improvement Rate Difference (see Murray et al., 2014).
The other major difference between the present study and other CAS treatment research, besides the increase in sample size and the higher level of evidence, was the range of participant age and severity included in this study. There was substantial variability on the primary outcome measures within treatment groups as demonstrated in the large standard deviations, particularly in performance at 1-week and 1-month posttreatment. However, age and severity were not correlated with overall change from pretreatment to 4-months posttreatment for each group, and in comparisons where age was correlated with performance, age was used as a covariate in analyses. Therefore, we are confident that the performance changes reported here are attributable to the treatments, although without a control group it is unknown how much of the change may be due to intensity rather than the specific treatments given.
Limitations
The intention of this study was to compare two treatments: an experimental treatment, ReST, and the most commonly used treatment in Australian practice, the NDP3. A nontreatment control group was not used. Control groups are recommended for future RCTs (e.g. a wait-list condition) to control for prospective maturation and allow more confident comparison between treatments when compared with no treatment.
This study assessed a range of covariates to demonstrate the groups were similar at baseline for valid comparison of the two treatments. Exhaustive assessment of other covariates, such as socioeconomic status and parental level of education, was not completed due to unknown prevalence and incidence of CAS and the relatively small sample size compared with all children who may have the disorder.
The frequently used severity measure, PCC, was used as it has been shown to correlate with intelligibility and also to allow comparison across studies (Shriberg et al., 1997). However, PCC only considers consonant accuracy and thus does not consider other aspects of CAS, such as vowel and prosodic accuracy, which is a limitation. A standardized, holistic measure of CAS severity is a priority for further research.
As acknowledged in the treatment protocol (Murray et al., 2012), we did not blind caregivers and therapists to the treatment conditions, although they were unaware of the study's hypotheses. The blinded outcome assessors were from the same larger community of speech pathologists and thus could have heard that two treatments were being delivered. However, colleagues had no way of knowing which treatment condition was assigned to the children, as the experimental probe was the same regardless of group assignment. Also as per the protocol, some participants resumed regular SLP services after their 1-month posttreatment probes. Therefore the 4-month posttreatment probe results also could have been influenced by other therapy. This could have had a positive or a negative consequence. An example of a negative consequence for either ReST or NDP3 treatment could include segmental accuracy treatment demonstrated with equal stress that could be detrimental to prosody. The executed protocol deviated from the published protocol in two ways: (a) outcome assessments were completed over a range of days at each time point, rather than on a single day, for logistic reasons, and (b) the instatement of another prepractice block in ReST if participants were not making any correct productions in two practice blocks in ReST. It is unlikely that these minor deviations affected the results.
As no stimulus generalization measures were used in this study, we cannot determine whether the treatment influenced the children's speech production with other communication partners or in other settings. Further research should include explicit measures of this type of generalization.
Conclusions and Future Directions
This world-first CAS RCT demonstrated the efficacy of both the ReST and NDP3 treatments, with significant clinical change in treated and untreated real words up to 4-months posttreatment. The results suggest that both the ReST and NDP3 treatments are clinically efficacious in treating the speech of 4–12-year-old verbal children with CAS, as strong generalization effects were demonstrated by both treatments (Olswang & Bain, 1994). Overall, ReST has greater external evidence to support its use with multiple peer-reviewed studies supporting its use (e.g., Ballard et al., 2010; McCabe et al., 2014) and demonstrated greater maintenance of treatment effects and generalization to untreated pseudowords that may have been supported by the research-based use of practice PML. The NDP3, however, performed better than initial estimates, and overall, it also demonstrated important ecologically valid change to real words, as well as some change to pseudoword stimuli. As such, it also has support for clinical use; however, inclusion of a practice phase with PML may be beneficial to plan for and facilitate greater maintenance and generalization effects. The results in this RCT are particularly strong considering random allocation of participants, use of blinded assessors, high levels of treatment fidelity and reliability, and the deliberately robust criterion of requiring simultaneous articulation, co-articulation, and prosodic accuracy for an item to be judged correct on the experimental probe.
For clinical use of these treatments, maintenance and generalization of treatment effects should be assessed, as well as collected treatment data (see Olswang & Bain, 1994, for a clinical tutorial). To facilitate translation into practice, most outcome measures were available clinical assessments (e.g. NDP3 assessment, DEAP, GFTA-2), and the protocol of our use of the treatments has been published (Murray et al., 2012).
There is ongoing need for high-quality CAS treatment research across the different phases of research (Fey & Finestack, 2009; Robey, 2004). Treatments will ultimately need to be matched to participant characteristics and delivered efficaciously and in a timely manner to reduce risk factors for children with CAS. Both the NDP3 and ReST programs would benefit from continued comparisons in Phase III research, with no-treatment (i.e., delayed treatment) group comparison, as well as comparison with other treatment approaches. Logical choices for such comparisons are approaches with early evidence for efficacy, such as Integral Stimulation/ DTTC and Integrated Phonological Awareness intervention. Both ReST and NDP3 treatments would also benefit from further Phase II research exploring the effect of intensity, individual response to treatment, and manipulation of PML. Phase IV effectiveness research in real-world clinical situations for both treatments is also now warranted. Investigation of neurological correlates of change would also be appropriate, as CAS is thought to be a neuromotor disorder and these preliminary results show some long-term maintenance and generalization.
Acknowledgments
We acknowledge our funding sources: the Douglas and Lola Douglas Scholarship on Child and Adolescent Health; Nadia Verrall Memorial 2010 and Postgraduate Student Scholarship 2011 through Speech Pathology Australia, James Kentley Memorial Scholarship, Postgraduate Research Support Schemes and Faculty of Health Sciences funding to Elizabeth Murray, the University of Sydney International Development Program Fund to Patricia McCabe and Kirrie J. Ballard, and the Australian Research Council Future Fellowship (FT120100255) to Kirrie J. Ballard. Parts of this study were presented at the 2012 Annual Speech Pathology Australia Conference. The authors also sincerely thank the families and children who participated. We thank the authors of the NDP3, Pamela Williams and Hilary Stephens, and Professor Donald A. Robin, who conceived the ReST program. We thank the treating and assessing clinicians, interns, and research assistants: Morin Beausoleil, Kate Broome, Sarah Coventry, Olivia Crowe, Claire Formby, Jennifer Fortin Zornow, Alyssa Gearin, Sally Hanna, Samantha Hardy, Loren Holmes, Amie Jakimyszyn, Melody Lam, Flora Lau, Angela Laundes, Claire Layfield, Catherine Mason, Sarah Masso, Anne McKenzie, Lauren Osborne, Aimee-Kate Parkes, Gemma Patterson, Alyssa Piper, Jemma Prag, Phoebe Sim, Donna Thomas, Lauri Vinokur, and Caitlin Winkelman. Many thanks to Shaun Langtry for IT support, and Robert Heard and Natalie Munro for statistical advice.
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Footnotes
1 Lexical stress in English pertains to within-word rhythm across syllables. Most words are classified as either strong–weak (SW, e.g. /pɜmɪt/) or weak–strong (WS, e.g. /pəmɪt/), with strong syllables having longer duration, greater loudness, and/or higher pitch than weak syllables.
Lexical stress in English pertains to within-word rhythm across syllables. Most words are classified as either strong–weak (SW, e.g. /pɜmɪt/) or weak–strong (WS, e.g. /pəmɪt/), with strong syllables having longer duration, greater loudness, and/or higher pitch than weak syllables.×
2 Assessments occurred within 1-week posttreatment but are referred to as “1-week” for brevity in the results.
Assessments occurred within 1-week posttreatment but are referred to as “1-week” for brevity in the results.×
Figure 1.

CONSORT flow chart of participant assignment, treatment, and follow up. aEach therapist saw two participants, one from each treatment group.

 CONSORT flow chart of participant assignment, treatment, and follow up. aEach therapist saw two participants, one from each treatment group.
Figure 1.

CONSORT flow chart of participant assignment, treatment, and follow up. aEach therapist saw two participants, one from each treatment group.

×
Figure 2.

Percent change in accuracy of production for treated items from pretreatment to 4-months posttreatment on the experimental probes. Pretreatment performance is normalized to zero due to the different stimuli used across treatments and the lack of significant differences at pretreatment between groups. Error bars represent 95% confidence intervals. The main effect of time and group and the interaction effect of time by group are significant, favoring NDP3 at pre- to 1-week posttreatment and favoring ReST at 1-week to 1-month and 4-months posttreatment.

 Percent change in accuracy of production for treated items from pretreatment to 4-months posttreatment on the experimental probes. Pretreatment performance is normalized to zero due to the different stimuli used across treatments and the lack of significant differences at pretreatment between groups. Error bars represent 95% confidence intervals. The main effect of time and group and the interaction effect of time by group are significant, favoring NDP3 at pre- to 1-week posttreatment and favoring ReST at 1-week to 1-month and 4-months posttreatment.
Figure 2.

Percent change in accuracy of production for treated items from pretreatment to 4-months posttreatment on the experimental probes. Pretreatment performance is normalized to zero due to the different stimuli used across treatments and the lack of significant differences at pretreatment between groups. Error bars represent 95% confidence intervals. The main effect of time and group and the interaction effect of time by group are significant, favoring NDP3 at pre- to 1-week posttreatment and favoring ReST at 1-week to 1-month and 4-months posttreatment.

×
Figure 3.

Accuracy of production for untreated real words from pretreatment to 4 months posttreatment on the experimental probes. Treatment effects were predicted to generalize to untreated real words at each child's generalization level. The main effect of time is significant for both groups from pretreatment to 1 week posttreatment and from 1 week posttreatment to both 1 month and 4 posttreatment.

 Accuracy of production for untreated real words from pretreatment to 4 months posttreatment on the experimental probes. Treatment effects were predicted to generalize to untreated real words at each child's generalization level. The main effect of time is significant for both groups from pretreatment to 1 week posttreatment and from 1 week posttreatment to both 1 month and 4 posttreatment.
Figure 3.

Accuracy of production for untreated real words from pretreatment to 4 months posttreatment on the experimental probes. Treatment effects were predicted to generalize to untreated real words at each child's generalization level. The main effect of time is significant for both groups from pretreatment to 1 week posttreatment and from 1 week posttreatment to both 1 month and 4 posttreatment.

×
Figure 4.

Accuracy of production for untreated pseudowords from pretreatment to 4-months posttreatment on the experimental probes for the ReST and NDP3 groups. Treatment effects were predicted to generalize to untreated pseudowords at each child's generalization level. The main effect of time is significant from pretreatment to 1-week posttreatment and from 1-week to both 1-month and 4-months posttreatment. There is a significant interaction effect favoring ReST from pretreatment to 1-week posttreatment.

 Accuracy of production for untreated pseudowords from pretreatment to 4-months posttreatment on the experimental probes for the ReST and NDP3 groups. Treatment effects were predicted to generalize to untreated pseudowords at each child's generalization level. The main effect of time is significant from pretreatment to 1-week posttreatment and from 1-week to both 1-month and 4-months posttreatment. There is a significant interaction effect favoring ReST from pretreatment to 1-week posttreatment.
Figure 4.

Accuracy of production for untreated pseudowords from pretreatment to 4-months posttreatment on the experimental probes for the ReST and NDP3 groups. Treatment effects were predicted to generalize to untreated pseudowords at each child's generalization level. The main effect of time is significant from pretreatment to 1-week posttreatment and from 1-week to both 1-month and 4-months posttreatment. There is a significant interaction effect favoring ReST from pretreatment to 1-week posttreatment.

×
Table 1. Treatment explanation and comparison of Rapid Syllable Transition (ReST) treatment and Nuffield Dyspraxia Programme–Third Edition (NDP3).
Treatment explanation and comparison of Rapid Syllable Transition (ReST) treatment and Nuffield Dyspraxia Programme–Third Edition (NDP3).×
ReST NDP3
Treatment goals/components Prepractice: To learn to say five pseudoword stimuli accurately with cues. Three individualized goals chosen for each participant across a hierarchy (Treatment Planning and Progression: Williams & Stephens, 2004).
Practice: To accurately produce 80% of 100 random trials.
Stimuli used in treatment 20 individualized pseudowords: At least 15 individualized, real-word pictured stimuli (minimum of five for each goal selected from the manual using psycholinguistics):
10 weak–strong lexical stress (e.g. “begarter” /bəgatə/) or 10 strong–weak lexical stress (e.g. “farbegee” /fabəgi/); final syllables were either strong ee (/i/) or weak er (/ə/).  • Phonotactic/prosodic goal (new structures/old sounds).
At either two syllable (CVCV) or three syllable (CVCVCV) level initially.  • Articulation goal (old structures/new sounds).
High target complexity: Highest level for child (that is stimulable). Low target complexity: Next step from child's current level.
Elicitation method Imitation of clinician's production. Spontaneous naming of picture stimuli.
Reading stimuli cards if participant was a fluent reader.
Treatment trials Prepractice: At least 5 trials (10–15 mins) Per goal: 30–40 trials (18 min each)
Practice: 100 trials (45–50 mins) Total trials per session: 100–120
Total trials per session: 100–120
Teaching strategies/cues Prepractice: Verbal instructions, modeling, tapping blocks, and breaking word up into parts and then putting them together again and orthographic stimuli. Prepractice: Verbal instructions, modeling, articulation, and visual-tactile cues (e.g., cued articulation) and pictured stimuli.
Practice: No cues. Practice: Not used.
Feedback Prepractice: KP for all trials. Prepractice: KP feedback for all trials. Correct responses followed by three repetitions of the same stimuli with feedback.
Practice: KR feedback (right/wrong) for a random 50% of the 100 trials after a 3-s delay. Practice: Not used.
Progression Practice: 80% accuracy over two sessions.  • 90% accuracy per stimuli.
 • For two syllable words move up to three syllable words.  • Add new stimuli at same level.
 • For three syllable words move up to carrier phrases (e.g. “Can I have a begarter?”)  • Achieved stimuli moved into maintenance.
Once five stimuli are achieved > next level of hierarchy
Summary of principles of motor learning Prepractice/acquisition-based: 25% of session Prepractice/acquisition-based: 100% of session
(Maas et al., 2008; McIlwaine, Madill, & McCabe, 2010)  • Blocked random practice  • Blocked random practice (approx. five practices of one stimulus before moving on to the next randomly selected)
 • Feedback 100% KP  • Feedback 100% KP
 • Cues for all incorrect productions  • Cues for all incorrect productions
Practice/ maintenance and generalization-based: 75% of session Practice/maintenance and generalization-based: Not done
 • No cues
 • Random practice
Feedback on outcome/results randomly for 50% of trials after 3-s delay
Note. KP = knowledge of performance; KR = knowledge of results.
Note. KP = knowledge of performance; KR = knowledge of results.×
Table 1. Treatment explanation and comparison of Rapid Syllable Transition (ReST) treatment and Nuffield Dyspraxia Programme–Third Edition (NDP3).
Treatment explanation and comparison of Rapid Syllable Transition (ReST) treatment and Nuffield Dyspraxia Programme–Third Edition (NDP3).×
ReST NDP3
Treatment goals/components Prepractice: To learn to say five pseudoword stimuli accurately with cues. Three individualized goals chosen for each participant across a hierarchy (Treatment Planning and Progression: Williams & Stephens, 2004).
Practice: To accurately produce 80% of 100 random trials.
Stimuli used in treatment 20 individualized pseudowords: At least 15 individualized, real-word pictured stimuli (minimum of five for each goal selected from the manual using psycholinguistics):
10 weak–strong lexical stress (e.g. “begarter” /bəgatə/) or 10 strong–weak lexical stress (e.g. “farbegee” /fabəgi/); final syllables were either strong ee (/i/) or weak er (/ə/).  • Phonotactic/prosodic goal (new structures/old sounds).
At either two syllable (CVCV) or three syllable (CVCVCV) level initially.  • Articulation goal (old structures/new sounds).
High target complexity: Highest level for child (that is stimulable). Low target complexity: Next step from child's current level.
Elicitation method Imitation of clinician's production. Spontaneous naming of picture stimuli.
Reading stimuli cards if participant was a fluent reader.
Treatment trials Prepractice: At least 5 trials (10–15 mins) Per goal: 30–40 trials (18 min each)
Practice: 100 trials (45–50 mins) Total trials per session: 100–120
Total trials per session: 100–120
Teaching strategies/cues Prepractice: Verbal instructions, modeling, tapping blocks, and breaking word up into parts and then putting them together again and orthographic stimuli. Prepractice: Verbal instructions, modeling, articulation, and visual-tactile cues (e.g., cued articulation) and pictured stimuli.
Practice: No cues. Practice: Not used.
Feedback Prepractice: KP for all trials. Prepractice: KP feedback for all trials. Correct responses followed by three repetitions of the same stimuli with feedback.
Practice: KR feedback (right/wrong) for a random 50% of the 100 trials after a 3-s delay. Practice: Not used.
Progression Practice: 80% accuracy over two sessions.  • 90% accuracy per stimuli.
 • For two syllable words move up to three syllable words.  • Add new stimuli at same level.
 • For three syllable words move up to carrier phrases (e.g. “Can I have a begarter?”)  • Achieved stimuli moved into maintenance.
Once five stimuli are achieved > next level of hierarchy
Summary of principles of motor learning Prepractice/acquisition-based: 25% of session Prepractice/acquisition-based: 100% of session
(Maas et al., 2008; McIlwaine, Madill, & McCabe, 2010)  • Blocked random practice  • Blocked random practice (approx. five practices of one stimulus before moving on to the next randomly selected)
 • Feedback 100% KP  • Feedback 100% KP
 • Cues for all incorrect productions  • Cues for all incorrect productions
Practice/ maintenance and generalization-based: 75% of session Practice/maintenance and generalization-based: Not done
 • No cues
 • Random practice
Feedback on outcome/results randomly for 50% of trials after 3-s delay
Note. KP = knowledge of performance; KR = knowledge of results.
Note. KP = knowledge of performance; KR = knowledge of results.×
×
Table 2. Group comparison of pretreatment variables.
Group comparison of pretreatment variables.×
Variable assessed ReST group (n = 13)
NDP3 group (n = 13)
F p
M (SD) Range M (SD) Range
Demographic
 Age in months 72.8 (27.5) [48–142] 62.5 (23.0) [48–120] 1.08 .31
 Sex 10 boys, 3 girls 8 boys, 5 girls 0.69 .42
 Had previous speech treatment? 13/13 13/13
Primary outcome measures at baseline
 Accuracy on items treated 10.8 (8.6) [0–28] 30.3 (20.3) [3–69] 1.53 .23
 Accuracy on items expected to generalize
  Untreated real-word 45.7 (15.1) [22–75] 44.0 (13.7) [24–66] 0.1 .76
  Untreated pseudoword 8.5 (9.7) [0–30] 11.1 (9.1) [1–28] 0.48 .49
Secondary outcome measures at baseline
 Connected speech (imitation accuracy > three word combinations) 35.2 (24.1) [0–81] 29.8 (22.9) [0–70] 0.32 .58
 DEAP Inconsistency 61.4 (12.6) [44–80] 65.8 (12.3) [44–88] 0.83 .37
 Single Word Test of Polysyllables
  PPC 53.9 (14.5) [25–81] 50.5 (16.9) [21–77] 0.31 .59
  PVC 51.7 (10.4) [39–70] 50.1 (13.1) [25–70] 0.12 .74
  PCC 56.2 (19.8) [28–93] 51.0 (21.7) [18–90] 0.41 .53
  Percent lexical stress matches 10.8 (7.4) [2–26] 9.1 (11.3) [0–42] 0.21 .66
 GFTA-2
 Standard score 66.0 (21.5) [40–97] 68.2 (20.4) [44–97] 0.21 .66
  PPC 65.7 (16.4) [41–92] 64.0 (13.9) [37–86] 0.07 .72
  PVC 71.3 (12.9) [51–93] 66.3 (14.8) [39–87] 0.84 .37
  PCC 57.1 (21.8) [30–97] 56.5 (22.4) [21–89] 0.01 .94
  Percent lexical stress matches 69.2 (19.8) [14–93] 56.9 (21.4) [19–86] 2.31 .14
 Severity ratings (based on Polysyllabic PCC)
  Severe n = 5 n = 7
  Moderate–severe n = 4 n = 3
  Mild–moderate n = 2 n = 2
  Mild n = 2 n = 1
 Language scores
  CELF-P2 / CELF-4 receptive language score 99.3 (9.1) [85–116] 105.3 (12.7) [86–130] 0.56 .46
  CELF-P2 / CELF-4 expressive language score 94.8 (15.3) [70–116] 101.6 (8.6) [88-115] 0.58 .81
Note. Bold designates pseudowords; — = not assessed. ReST = Rapid Syllable Transition treatment; NDP3 = Nuffield Dyspraxia Programme–Third Edition; F = ANOVA statistic; p = significance set at 0.05; DEAP Inconsistency = Diagnostic Evaluation of Articulation and Phonology Inconsistency test; PPC = percent phonemes correct; PVC = percent vowels correct; PCC = percent consonants correct; GFTA-2 = Goldman-Fristoe Test of Articulation–Second Edition; CELF-P2 = Clinical Evaluation of Language Fundamentals-Preschool–Second Edition; CELF-4 = Clinical Evaluation of Language Fundamentals–Fourth Edition.
Note. Bold designates pseudowords; — = not assessed. ReST = Rapid Syllable Transition treatment; NDP3 = Nuffield Dyspraxia Programme–Third Edition; F = ANOVA statistic; p = significance set at 0.05; DEAP Inconsistency = Diagnostic Evaluation of Articulation and Phonology Inconsistency test; PPC = percent phonemes correct; PVC = percent vowels correct; PCC = percent consonants correct; GFTA-2 = Goldman-Fristoe Test of Articulation–Second Edition; CELF-P2 = Clinical Evaluation of Language Fundamentals-Preschool–Second Edition; CELF-4 = Clinical Evaluation of Language Fundamentals–Fourth Edition.×
Table 2. Group comparison of pretreatment variables.
Group comparison of pretreatment variables.×
Variable assessed ReST group (n = 13)
NDP3 group (n = 13)
F p
M (SD) Range M (SD) Range
Demographic
 Age in months 72.8 (27.5) [48–142] 62.5 (23.0) [48–120] 1.08 .31
 Sex 10 boys, 3 girls 8 boys, 5 girls 0.69 .42
 Had previous speech treatment? 13/13 13/13
Primary outcome measures at baseline
 Accuracy on items treated 10.8 (8.6) [0–28] 30.3 (20.3) [3–69] 1.53 .23
 Accuracy on items expected to generalize
  Untreated real-word 45.7 (15.1) [22–75] 44.0 (13.7) [24–66] 0.1 .76
  Untreated pseudoword 8.5 (9.7) [0–30] 11.1 (9.1) [1–28] 0.48 .49
Secondary outcome measures at baseline
 Connected speech (imitation accuracy > three word combinations) 35.2 (24.1) [0–81] 29.8 (22.9) [0–70] 0.32 .58
 DEAP Inconsistency 61.4 (12.6) [44–80] 65.8 (12.3) [44–88] 0.83 .37
 Single Word Test of Polysyllables
  PPC 53.9 (14.5) [25–81] 50.5 (16.9) [21–77] 0.31 .59
  PVC 51.7 (10.4) [39–70] 50.1 (13.1) [25–70] 0.12 .74
  PCC 56.2 (19.8) [28–93] 51.0 (21.7) [18–90] 0.41 .53
  Percent lexical stress matches 10.8 (7.4) [2–26] 9.1 (11.3) [0–42] 0.21 .66
 GFTA-2
 Standard score 66.0 (21.5) [40–97] 68.2 (20.4) [44–97] 0.21 .66
  PPC 65.7 (16.4) [41–92] 64.0 (13.9) [37–86] 0.07 .72
  PVC 71.3 (12.9) [51–93] 66.3 (14.8) [39–87] 0.84 .37
  PCC 57.1 (21.8) [30–97] 56.5 (22.4) [21–89] 0.01 .94
  Percent lexical stress matches 69.2 (19.8) [14–93] 56.9 (21.4) [19–86] 2.31 .14
 Severity ratings (based on Polysyllabic PCC)
  Severe n = 5 n = 7
  Moderate–severe n = 4 n = 3
  Mild–moderate n = 2 n = 2
  Mild n = 2 n = 1
 Language scores
  CELF-P2 / CELF-4 receptive language score 99.3 (9.1) [85–116] 105.3 (12.7) [86–130] 0.56 .46
  CELF-P2 / CELF-4 expressive language score 94.8 (15.3) [70–116] 101.6 (8.6) [88-115] 0.58 .81
Note. Bold designates pseudowords; — = not assessed. ReST = Rapid Syllable Transition treatment; NDP3 = Nuffield Dyspraxia Programme–Third Edition; F = ANOVA statistic; p = significance set at 0.05; DEAP Inconsistency = Diagnostic Evaluation of Articulation and Phonology Inconsistency test; PPC = percent phonemes correct; PVC = percent vowels correct; PCC = percent consonants correct; GFTA-2 = Goldman-Fristoe Test of Articulation–Second Edition; CELF-P2 = Clinical Evaluation of Language Fundamentals-Preschool–Second Edition; CELF-4 = Clinical Evaluation of Language Fundamentals–Fourth Edition.
Note. Bold designates pseudowords; — = not assessed. ReST = Rapid Syllable Transition treatment; NDP3 = Nuffield Dyspraxia Programme–Third Edition; F = ANOVA statistic; p = significance set at 0.05; DEAP Inconsistency = Diagnostic Evaluation of Articulation and Phonology Inconsistency test; PPC = percent phonemes correct; PVC = percent vowels correct; PCC = percent consonants correct; GFTA-2 = Goldman-Fristoe Test of Articulation–Second Edition; CELF-P2 = Clinical Evaluation of Language Fundamentals-Preschool–Second Edition; CELF-4 = Clinical Evaluation of Language Fundamentals–Fourth Edition.×
×
Table 3. Levels of stimulus complexity guiding selection of treated items and comparable real-word items for measuring response generalization.
Levels of stimulus complexity guiding selection of treated items and comparable real-word items for measuring response generalization.×
Stimulus complexity Participant's treatment items (for allocated treatment) Participant's generalization items (for both treatments)
Untreated real-word items Untreated pseudoword items
Level 1 ReST • Consonants and vowels in isolation. • Two-syllable ReST stimulia (similar to NDP3 CVCV goal stimuli with known or highly stimulable sounds that were treated).
• Two-syllable stimuli (if stepped up to three-syllable stimuli, moved to Level 2). • One-syllable words (CV and CVC) from NDP3 stimuli and additional stimuli.
NDP3 • Two-syllable words (CVCV) from NDP3 stimuli and additional stimuli.a
• single sound, CV, VC, CVCV,a and CVC goals.
Level 2 ReST Level 1 items, plus • Three-syllable ReST stimulia (similar to NDP3 multisyllabic goal stimuli with known or highly stimulable sounds that were treated).
• Three-syllable stimulia (if stepped up to three-syllable stimuli in carrier phrases, moved to Level 3). • Three-syllable word from additional stimuli.a
NDP3 • Multisyllabic NDP3 stimuli.a
• Any two of single sound, CV, VC, CVCV,a CVC.
And multisyllabica words.
Level 3 ReST Level 1 and 2 items, plus • Three-syllable ReST stimuli (similar to NDP3 multisyllabic goal stimuli with known or highly stimulable sounds that were treated).
• Three-syllable stimuli.a • NDP3 clusters. • Three-syllable stimuli in carrier phrases (similar to NDP phrasal stimuli with known sounds).
• Three-syllable stimuli in carrier phrasesa (as stepped up in treatment). • NDP3 phrases.
NDP3
• Any two of single sound, CV, VC, CVCV,a CVC, multisyllabica words and clusters.
• And everyday phrases.a
a These stimuli were used to address or assess lexical/phrasal stress in addition to articulation. ReST = Rapid Syllable transition treatment; NDP3 = Nuffield Dyspraxia Programme–Third Edition.
These stimuli were used to address or assess lexical/phrasal stress in addition to articulation. ReST = Rapid Syllable transition treatment; NDP3 = Nuffield Dyspraxia Programme–Third Edition.×
Table 3. Levels of stimulus complexity guiding selection of treated items and comparable real-word items for measuring response generalization.
Levels of stimulus complexity guiding selection of treated items and comparable real-word items for measuring response generalization.×
Stimulus complexity Participant's treatment items (for allocated treatment) Participant's generalization items (for both treatments)
Untreated real-word items Untreated pseudoword items
Level 1 ReST • Consonants and vowels in isolation. • Two-syllable ReST stimulia (similar to NDP3 CVCV goal stimuli with known or highly stimulable sounds that were treated).
• Two-syllable stimuli (if stepped up to three-syllable stimuli, moved to Level 2). • One-syllable words (CV and CVC) from NDP3 stimuli and additional stimuli.
NDP3 • Two-syllable words (CVCV) from NDP3 stimuli and additional stimuli.a
• single sound, CV, VC, CVCV,a and CVC goals.
Level 2 ReST Level 1 items, plus • Three-syllable ReST stimulia (similar to NDP3 multisyllabic goal stimuli with known or highly stimulable sounds that were treated).
• Three-syllable stimulia (if stepped up to three-syllable stimuli in carrier phrases, moved to Level 3). • Three-syllable word from additional stimuli.a
NDP3 • Multisyllabic NDP3 stimuli.a
• Any two of single sound, CV, VC, CVCV,a CVC.
And multisyllabica words.
Level 3 ReST Level 1 and 2 items, plus • Three-syllable ReST stimuli (similar to NDP3 multisyllabic goal stimuli with known or highly stimulable sounds that were treated).
• Three-syllable stimuli.a • NDP3 clusters. • Three-syllable stimuli in carrier phrases (similar to NDP phrasal stimuli with known sounds).
• Three-syllable stimuli in carrier phrasesa (as stepped up in treatment). • NDP3 phrases.
NDP3
• Any two of single sound, CV, VC, CVCV,a CVC, multisyllabica words and clusters.
• And everyday phrases.a
a These stimuli were used to address or assess lexical/phrasal stress in addition to articulation. ReST = Rapid Syllable transition treatment; NDP3 = Nuffield Dyspraxia Programme–Third Edition.
These stimuli were used to address or assess lexical/phrasal stress in addition to articulation. ReST = Rapid Syllable transition treatment; NDP3 = Nuffield Dyspraxia Programme–Third Edition.×
×
Table 4. Means (standard deviations) for treatment and generalization measures.
Means (standard deviations) for treatment and generalization measures.×
Treatment group Pretreatment
1-week posttreatment
1-month posttreatment
4-months posttreatment
ReST NDP3 ReST NDP3 ReST NDP3 ReST NDP3
Primary outcomes
 Accuracy on items treated 10.8 (8.6) 30.3 (20.3) 34.8 (24.4) 70.1 (16.3) 44.7 (22.8) 66.3 (20.4) 45.0 (19.4)a 60.2 (12.2)
 Accuracy on items expected to generalize
  Untreated real-words 44.0 (13.7) 45.7 (15.1) 58.1 (19.2) 56.7 (18.5) 62.3 (19.9) 63.9 (20.9) 62.0 (17.9) 66.5 (16.2)
  Untreated pseudowords 8.5 (9.7) 11.1 (9.1) 29.6 (19.4) 16.2 (20.7) 37.5 (24.8) 33.9 (30.3) 38.8 (17.5) 31.4 (25.5)
Secondary measures
 Connected speech (imitation accuracy in >three word combinations) 35.2 (24.1) 29.8 (22.9) 44.8 (28.6) 42.8 (26.2) 46.7 (19.5) 44.1 (24.0) 50.7 (20.2) 49.4 (26.7)
 DEAP Inconsistency 61.4 (12.6) 65.8 (12.3) 48.5 (16.3) 47.5 (19.3) 50.5 (21.3) 54.7 (18.9) 56.3 (13.7) 52.5 (28.4)
 Single-Word Test of Polysyllables
  PPC 53.9 (14.5) 50.5 (16.7) 63.5 (17.9) 57.5 (20.2)
  PVC 51.7 (10.4) 50.1 (13.1) 70.2 (14.8) 62.0 (16.7)
  PCC 56.2 (19.8) 51.0 (21.7) 56.8 (22.9) 52.9 (27.2)
  Percent lexical stress matches 10.8 (7.4) 9.1 (11.3) 44.4 (25.9) 33.1 (20.5)
 GFTA-2
  PPC 62.0 (19.5) 63.8 (13.5) 75.8 (15.6) 66.8 (27.5)
  PVC 71.3 (12.9) 66.3 (14.8) 85.5 (10.8) 83.3 (12.8)
  PCC 57.1 (21.8) 56.5 (22.4) 66.1 (21.0) 61.5 (28.6)
  Percent lexical stress matches 69.2 (19.8) 56.9 (21.4) 87.9 (9.6) 85.3 (12.2)
a Indicates treated pseudowords; — = not assessed. ReST = Rapid Syllable Transition treatment; NDP3 = Nuffield Dyspraxia Programme–Third Edition; DEAP Inconsistency = Diagnostic Evaluation of Articulation and Phonology Inconsistency test; PPC = percent phonemes correct; PVC = percent vowels correct; PCC = percent consonants correct; GFTA-2 = Goldman-Fristoe Test of Articulation–Second Edition.
Indicates treated pseudowords; — = not assessed. ReST = Rapid Syllable Transition treatment; NDP3 = Nuffield Dyspraxia Programme–Third Edition; DEAP Inconsistency = Diagnostic Evaluation of Articulation and Phonology Inconsistency test; PPC = percent phonemes correct; PVC = percent vowels correct; PCC = percent consonants correct; GFTA-2 = Goldman-Fristoe Test of Articulation–Second Edition.×
Table 4. Means (standard deviations) for treatment and generalization measures.
Means (standard deviations) for treatment and generalization measures.×
Treatment group Pretreatment
1-week posttreatment
1-month posttreatment
4-months posttreatment
ReST NDP3 ReST NDP3 ReST NDP3 ReST NDP3
Primary outcomes
 Accuracy on items treated 10.8 (8.6) 30.3 (20.3) 34.8 (24.4) 70.1 (16.3) 44.7 (22.8) 66.3 (20.4) 45.0 (19.4)a 60.2 (12.2)
 Accuracy on items expected to generalize
  Untreated real-words 44.0 (13.7) 45.7 (15.1) 58.1 (19.2) 56.7 (18.5) 62.3 (19.9) 63.9 (20.9) 62.0 (17.9) 66.5 (16.2)
  Untreated pseudowords 8.5 (9.7) 11.1 (9.1) 29.6 (19.4) 16.2 (20.7) 37.5 (24.8) 33.9 (30.3) 38.8 (17.5) 31.4 (25.5)
Secondary measures
 Connected speech (imitation accuracy in >three word combinations) 35.2 (24.1) 29.8 (22.9) 44.8 (28.6) 42.8 (26.2) 46.7 (19.5) 44.1 (24.0) 50.7 (20.2) 49.4 (26.7)
 DEAP Inconsistency 61.4 (12.6) 65.8 (12.3) 48.5 (16.3) 47.5 (19.3) 50.5 (21.3) 54.7 (18.9) 56.3 (13.7) 52.5 (28.4)
 Single-Word Test of Polysyllables
  PPC 53.9 (14.5) 50.5 (16.7) 63.5 (17.9) 57.5 (20.2)
  PVC 51.7 (10.4) 50.1 (13.1) 70.2 (14.8) 62.0 (16.7)
  PCC 56.2 (19.8) 51.0 (21.7) 56.8 (22.9) 52.9 (27.2)
  Percent lexical stress matches 10.8 (7.4) 9.1 (11.3) 44.4 (25.9) 33.1 (20.5)
 GFTA-2
  PPC 62.0 (19.5) 63.8 (13.5) 75.8 (15.6) 66.8 (27.5)
  PVC 71.3 (12.9) 66.3 (14.8) 85.5 (10.8) 83.3 (12.8)
  PCC 57.1 (21.8) 56.5 (22.4) 66.1 (21.0) 61.5 (28.6)
  Percent lexical stress matches 69.2 (19.8) 56.9 (21.4) 87.9 (9.6) 85.3 (12.2)
a Indicates treated pseudowords; — = not assessed. ReST = Rapid Syllable Transition treatment; NDP3 = Nuffield Dyspraxia Programme–Third Edition; DEAP Inconsistency = Diagnostic Evaluation of Articulation and Phonology Inconsistency test; PPC = percent phonemes correct; PVC = percent vowels correct; PCC = percent consonants correct; GFTA-2 = Goldman-Fristoe Test of Articulation–Second Edition.
Indicates treated pseudowords; — = not assessed. ReST = Rapid Syllable Transition treatment; NDP3 = Nuffield Dyspraxia Programme–Third Edition; DEAP Inconsistency = Diagnostic Evaluation of Articulation and Phonology Inconsistency test; PPC = percent phonemes correct; PVC = percent vowels correct; PCC = percent consonants correct; GFTA-2 = Goldman-Fristoe Test of Articulation–Second Edition.×
×
Table 5. ANOVA and ANCOVA comparisons for outcomes measured at all time points.
ANOVA and ANCOVA comparisons for outcomes measured at all time points.×
Statistical comparisons Pretreatment to 1-week posttreatment
1-week to 1-month posttreatment
1-week to 4-months posttreatment
Time Group Time × Group Time Group Time × Group Time Group Time × Group
Primary Outcomes
 Accuracy on items treateda F = 5.92* F = 40.81** F = 4.28* F = 3.48 F = 23.85** F = 4.48* F = 6.79* F = 26.31** F = 9.52**
(NDP3 ) (NDP3 ) (ReST ) (ReST ) (ReST ) (ReST )
 Accuracy on items expected to generalize
  Untreated real words F = 40.747** F = 0.064 F = 0.006 F = 6.512* F < 0.001 F = 0.549 F = 6.201* F = 0.055 F = 1.155
  Untreated pseudowords F = 14.997* F = 1.132 F = 5.634* F =11.734** F = 0.952 F = 1.799 F = 9.757** F = 1.275 F = 2.382
(ReST )
Secondary Outcomes
 Connected speech (imitation of > three word combinations) F = 28.401** F = 0.129 F = 0.628 F = 0.268 F = 0.057 F = 0.012 F = 3.459 F = 0.026 F = 0.009
 DEAP Inconsistency F = 54.166** F = 0.102 F = 1.572 F = 1.650 F = 0.015 F = 0.355 F = 2.379 F = 0.120 F = 0.136
Note. df(1, 25) for all comparisons.
Note. df(1, 25) for all comparisons.×
a ANCOVA used.
ANCOVA used.×
* p = .05,
p = .05,×
** p = .01.
p = .01.×
= better performance.
= better performance.×
Table 5. ANOVA and ANCOVA comparisons for outcomes measured at all time points.
ANOVA and ANCOVA comparisons for outcomes measured at all time points.×
Statistical comparisons Pretreatment to 1-week posttreatment
1-week to 1-month posttreatment
1-week to 4-months posttreatment
Time Group Time × Group Time Group Time × Group Time Group Time × Group
Primary Outcomes
 Accuracy on items treateda F = 5.92* F = 40.81** F = 4.28* F = 3.48 F = 23.85** F = 4.48* F = 6.79* F = 26.31** F = 9.52**
(NDP3 ) (NDP3 ) (ReST ) (ReST ) (ReST ) (ReST )
 Accuracy on items expected to generalize
  Untreated real words F = 40.747** F = 0.064 F = 0.006 F = 6.512* F < 0.001 F = 0.549 F = 6.201* F = 0.055 F = 1.155
  Untreated pseudowords F = 14.997* F = 1.132 F = 5.634* F =11.734** F = 0.952 F = 1.799 F = 9.757** F = 1.275 F = 2.382
(ReST )
Secondary Outcomes
 Connected speech (imitation of > three word combinations) F = 28.401** F = 0.129 F = 0.628 F = 0.268 F = 0.057 F = 0.012 F = 3.459 F = 0.026 F = 0.009
 DEAP Inconsistency F = 54.166** F = 0.102 F = 1.572 F = 1.650 F = 0.015 F = 0.355 F = 2.379 F = 0.120 F = 0.136
Note. df(1, 25) for all comparisons.
Note. df(1, 25) for all comparisons.×
a ANCOVA used.
ANCOVA used.×
* p = .05,
p = .05,×
** p = .01.
p = .01.×
= better performance.
= better performance.×
×
Table 6. Statistical comparisons for Single-Word Test of Polysyllables and Goldman-Fristoe Test of Articulation–Second Edition (GFTA-2).
Statistical comparisons for Single-Word Test of Polysyllables and Goldman-Fristoe Test of Articulation–Second Edition (GFTA-2).×
Measure Pretreatment to 1-month posttreatment
Time Group Time × Group
Single-Word Test of Polysyllablesa
 PPC F = 2.896 F = 0.044 F = 0.458
 PVC F = 6.053* F = 0.319 F = 2.033
 PCC F = 0.545 F = 0.001 F = 0.017
 Percent lexical stress matches F = 5.507* F = 0.480 F = 1.246
GFTA-2
 PPC F = 29.207** F = 0.016 F = 1.593
 PVC F = 73.648** F = 0.596 F = 0.592
 PCC F = 7.742** F = 0.870 F = 0.616
 Percent lexical stress matches F = 39.735** F = 2.008 F = 1.691
Note. df(1, 25) for all comparisons;
Note. df(1, 25) for all comparisons;×
a ANCOVA used;
ANCOVA used;×
* p = .05;
p = .05;×
** p = .01.
p = .01.×
Table 6. Statistical comparisons for Single-Word Test of Polysyllables and Goldman-Fristoe Test of Articulation–Second Edition (GFTA-2).
Statistical comparisons for Single-Word Test of Polysyllables and Goldman-Fristoe Test of Articulation–Second Edition (GFTA-2).×
Measure Pretreatment to 1-month posttreatment
Time Group Time × Group
Single-Word Test of Polysyllablesa
 PPC F = 2.896 F = 0.044 F = 0.458
 PVC F = 6.053* F = 0.319 F = 2.033
 PCC F = 0.545 F = 0.001 F = 0.017
 Percent lexical stress matches F = 5.507* F = 0.480 F = 1.246
GFTA-2
 PPC F = 29.207** F = 0.016 F = 1.593
 PVC F = 73.648** F = 0.596 F = 0.592
 PCC F = 7.742** F = 0.870 F = 0.616
 Percent lexical stress matches F = 39.735** F = 2.008 F = 1.691
Note. df(1, 25) for all comparisons;
Note. df(1, 25) for all comparisons;×
a ANCOVA used;
ANCOVA used;×
* p = .05;
p = .05;×
** p = .01.
p = .01.×
×
Supplemental Appendix.Case example of Nuffield Dyspraxia Programme–Third Edition (NDP3; Williams & Stephens, 2004) goals, target selection, and progression