A further analysis for developmental apraxia of speech in children with defective articulation

This paper reports a further analysis of behaviors that might distinguish developmental apraxia of speech from "functional" defective articulation. Closely following a study of Yoss and Darley, 30 children with moderately-to-severely defective articulation but with normal hearing, intelligence, and language development and with no apparent organic etiology for their disability were matched with a normal-speaking control group. Both groups were given Yoss and Darley's battery of speech and nonspeech tasks. Yoss and Darley's analysis procedure was applied to the data. Their finding of significant differences between the control group and the defective articulation group across five nonspeech tasks proved to be true for ony two of the speech and nonspeech tasks in this study. Following division of the defective articulation group on the basis of isolated volitional oral and movement scores, Yoss and Darley had conducted discriminant function analyses of the data, resulting in combinations of speech and nonspeech variables that significantly differentiated the two subgroups. Neurologic ratings figured prominently as a distinguishing variable. A similar comparison in this study did not find a combination of variables which differentiated the two subgroups with any confidence. The implication of these findings and some possible reasons for the differences between the findings of the studies are discussed.