Effectiveness of speech intervention for phonological disorders: a randomized controlled trial.

Thirty children of preschool age with severe phonological disorders were randomly assigned to two treatment groups. Group 1 received treatment for 4 months followed by 4 months without treatment while group 2 underwent 4 months without treatment followed by 4 months of treatment. The outcome measures used were the Assessment of Phonological Processes-Revised (APP-R), the Goldman-Fristoe Test of Articulation (GFTA), the Percentage Consonants Correct (PCC), and Mean Length of Utterance (MLU). Group 1 showed significant differences on scores of phonological measures (APP-R, GFTA, and PCC) after the first 4 months of the study. At the 8-month assessment point the measures for conversational speech intelligibility continued to be significantly different, with group 1 scores higher than those of group 2. The expressive language measure did not detect a difference between groups at any time; however group 1 scores were consistently higher than group 2 scores.