Sound Production Treatment: Synthesis and Quantification of Outcomes.

PURPOSE: This investigation was designed to provide a quantification and synthesis of a series of single-case experimental design investigations into the effects of sound production treatment, an articulatory-kinematic treatment for acquired apraxia of speech (AOS). The main purpose was to perform a meta-analysis of aggregated sound production treatment data in order to provide benchmarks to serve as indicators of magnitude of change. Additional analyses explored various factors influencing effect sizes and level of performance.
METHOD: Effect sizes were calculated for treated and untreated items for 24 participants across 10 investigations. Benchmarks were calculated as the quartiles of the distributions of the effect sizes. Correlational analyses were performed to examine (a) end-of-treatment performance relative to follow-up performance, (b) response of trained items relative to untrained items, and (c) effect size relative to participant variables.
RESULTS: Effect sizes were predominantly large and positive; benchmarks for treated items were larger than those for untreated items. End of treatment and follow-up performance were positively correlated, and response generalization was positively correlated with AOS severity.
CONCLUSION: These benchmarks may assist in evaluating the effects of interventions for individuals with AOS utilizing similar outcome measures in both clinical and research settings.