Speech Perception and Motor Control in Children and Adolescents with Down Syndrome

Abstract

Twelve children without intellectual disability and 12 children and adolescents with Down syndrome were administered a short form of Roy and Black's (1998) Apraxia Battery. Participants with Down syndrome also completed a free-recall dichotic listening test. While the mean laterality indices for the group with Down syndrome was negative, indicative of a left ear-right hemisphere specialization for speech perception, they were not significantly different from zero. There was a wide range of individual variability in laterality, and individuals with a left ear advantage for speech perception performed more poorly on the portions of the apraxia battery that involved verbal instruction. The possibility that individuals with Down syndrome who have apraxia may constitute an important subset of individuals with Down syndrome was considered. The results are discussed within the framework of Elliott, Weeks, and Elliott's (1987) biological dissociation model.