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AJSLP-16-0225smit_SuppS1.pdf (412.68 kB)

Outcome measures in phonological treatment (Smit et al., 2018)

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journal contribution
posted on 2018-02-21, 17:19 authored by Ann Bosma Smit, Klaire Mann Brumbaugh, Barbara Weltsch, Melanie Hilgers
Purpose: In a feasibility study for a randomized controlled trial of treatments for phonological disorders conducted over a period of 8 months, we examined 6 clinically relevant outcome measures. We took steps to reduce error variance and to maximize systematic variance.
Method: Six children received traditional treatment (Van Riper, 1939), and 7 received expansion points (Smit, 2000), a treatment program with both phonological and traditional elements. Outcome measures, which were applied to both word list and conversational samples, included percentage of consonants correct (PCC; Shriberg & Kwiatkowski, 1982), PCC for late and/or difficult (L /D) consonants and number of L/D consonants acquired.
Results: In repeated-measures analyses of variance, all measures showed significant differences from pretreatment to posttreatment, and the word list measures were associated with very high power values. In analyses of covariance for between-groups contrasts, the adjusted expansion points mean exceeded the adjusted traditional treatment mean for every measure; however, no differences reached significance. For the L /D PCC (conversation) measure, the contrast
between groups was associated with a large effect size.
Conclusion: We recommend that practitioners use outcome measures related to a word list. We recommend that researchers consider using L/D PCC on the basis of conversational samples to detect differences among treatment groups.

Supplemental Material S1. Ancillary analyses.

Smit, A. B., Brumbaugh, K. M., Weltsch, B., & Hilgers, M. (2018). Treatment of phonological disorder: A feasibility study with focus on outcome measures. American Journal of Speech-Language Pathology, 27, 553–565.


The authors are grateful to Kansas State University for a Faculty Development Award for 2009–2010, to the College of Human Ecology for two SRO grants (one for 2008–2009 and one for 2010–2011), and to the Program in Communication Sciences and Disorders for several small grants that made this research possible. The authors thank United School District 383 for the support provided by the Speech Groups contract.