Cerebral specialization in individuals with Down syndrome.

Recent research in which investigators examined cerebral specialization in individuals with Down syndrome was reviewed. Although dichotic listening studies seem to indicate that individuals with Down syndrome are more likely than those without Down syndrome to display a left ear/right hemisphere advantage for speech sounds, evidence from other experimental paradigms makes a simple model of reversed cerebral specialization for individuals with Down syndrome untenable. We proposed a model of cerebral specialization that has as its main feature the biological dissociation between speech perception and the production of speech and other complex movements. In light of this feature, possible directions for future research were discussed.