Cerebral specialisation for receptive language in individuals with down syndrome

Two experiments examined cerebral specialisation for linguistic material in adults with Down syndrome (DS). For a dihaptic letter matching task, a left hand/right hemisphere advantage was observed for the DS group. For a visual field letter identification task, the DS data were suggestive of a left field/right hemisphere superiority. Thus, as predicted by our model (Elliott, Weeks, & Elliott, 1987), atypical cerebral organisation of speech perception is evident in persons with DS. Moreover, the functional disconnection of neural systems subserving the control of complex movement and those responsible for speech perception can be generalised to include the haptic and visual processing of linguistic material.