Comparison of Percentage of Syllables Stuttered With Parent-Reported Severity Ratings as a Primary Outcome Measure in Clinical Trials of Early Stuttering Treatment Purpose This report investigates whether parent-reported stuttering severity ratings (SRs) provide similar estimates of effect size as percentage of syllables stuttered (%SS) for randomized trials of early stuttering treatment with preschool children. Method Data sets from 3 randomized controlled trials of an early stuttering intervention were selected for ... Research Article
Research Article  |   April 17, 2018
Comparison of Percentage of Syllables Stuttered With Parent-Reported Severity Ratings as a Primary Outcome Measure in Clinical Trials of Early Stuttering Treatment
 
Author Affiliations & Notes
  • Mark Onslow
    The University of Sydney, Australian Stuttering Research Centre, Lidcombe, New South Wales
  • Mark Jones
    The University of Queensland, School of Public Health, Faculty of Medicine, Brisbane, Australia
  • Sue O'Brian
    The University of Sydney, Australian Stuttering Research Centre, Lidcombe, New South Wales
  • Ann Packman
    The University of Sydney, Australian Stuttering Research Centre, Lidcombe, New South Wales
  • Ross Menzies
    The University of Sydney, Australian Stuttering Research Centre, Lidcombe, New South Wales
  • Robyn Lowe
    The University of Sydney, Australian Stuttering Research Centre, Lidcombe, New South Wales
  • Simone Arnott
    Australian Catholic University, School of Allied and Public Health, Melbourne
  • Kate Bridgman
    La Trobe University, Department of Human Communication Science, Melbourne, Australia
  • Caroline de Sonneville
    Erasmus University Medical Centre, Rotterdam, the Netherlands
  • Marie-Christine Franken
    Erasmus University Medical Centre, Rotterdam, the Netherlands
  • 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 Mark Onslow: mark.onslow@sydney.edu.au
  • Editor: Julie Liss
    Editor: Julie Liss×
  • Associate Editor: Courtney Byrd
    Associate Editor: Courtney Byrd×
Article Information
Speech, Voice & Prosodic Disorders / Fluency Disorders / Research Issues, Methods & Evidence-Based Practice / Speech, Voice & Prosody / Speech / Research Articles
Research Article   |   April 17, 2018
Comparison of Percentage of Syllables Stuttered With Parent-Reported Severity Ratings as a Primary Outcome Measure in Clinical Trials of Early Stuttering Treatment
Journal of Speech, Language, and Hearing Research, April 2018, Vol. 61, 811-819. doi:10.1044/2017_JSLHR-S-16-0448
History: Received December 8, 2016 , Revised May 21, 2017 , Accepted November 16, 2017
 
Journal of Speech, Language, and Hearing Research, April 2018, Vol. 61, 811-819. doi:10.1044/2017_JSLHR-S-16-0448
History: Received December 8, 2016; Revised May 21, 2017; Accepted November 16, 2017

Purpose This report investigates whether parent-reported stuttering severity ratings (SRs) provide similar estimates of effect size as percentage of syllables stuttered (%SS) for randomized trials of early stuttering treatment with preschool children.

Method Data sets from 3 randomized controlled trials of an early stuttering intervention were selected for analyses. Analyses included median changes and 95% confidence intervals per treatment group, Bland–Altman plots, analysis of covariance, and Spearman rho correlations.

Results Both SRs and %SS showed large effect sizes from pretreatment to follow-up, although correlations between the 2 measures were moderate at best. Absolute agreement between the 2 measures improved as percentage reduction of stuttering frequency and severity increased, probably due to innate measurement limitations for participants with low baseline severity. Analysis of covariance for the 3 trials showed consistent results.

Conclusion There is no statistical reason to favor %SS over parent-reported stuttering SRs as primary outcomes for clinical trials of early stuttering treatment. However, there are logistical reasons to favor parent-reported stuttering SRs. We conclude that parent-reported rating of the child's typical stuttering severity for the week or month prior to each assessment is a justifiable alternative to %SS as a primary outcome measure in clinical trials of early stuttering treatment.

Acknowledgments
This research was supported by a National Health and Medical Research Council of Australia Program Grant 633007 awarded to the Australian Stuttering Research Centre. The authors thank Toni Rietveld and Lisa Iverach for helpful contributions during preparation of the article.
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