Cerebral specialization for speech perception and movement organization in adults with Down's syndrome.
Adults with Down's syndrome and a group of undifferentiated mentally handicapped persons were examined using a free recall dichotic listening procedure to determine a laterality index for the perception of speech sounds. Subjects also performed both the visual and verbal portions of a standard apraxia battery. As in previous research, subjects with Down's syndrome tended to display a left ear advantage on the dichotic listening test. As well, they performed better on the apraxia battery when movements were cued visually rather than verbally. This verbal-motor disadvantage increased as the left ear dichotic listening advantage became more pronounced. It is argued that the verbal-motor difficulties experienced by persons with Down's syndrome stem from a dissociation of the functional systems responsible for speech perception and movement organization (Elliott and Weeks, 1990).
Elliott
D
D
Department of Physical Education, McMaster University, Hamilton, Ontario, Canada.
Weeks
D J
DJ
D000368:Aged; D001072:Apraxias / Q000175:diagnosis / Q000523:psychology; D004007:Dichotic Listening Tests; D004292:Dominance, Cerebral; D004314:Down Syndrome / Q000175:diagnosis / Q000523:psychology*; D005260:Female; D007839:Functional Laterality; D006801:Humans; D008297:Male; D011939:Mental Recall; D008875:Middle Aged; D009483:Neuropsychological Tests; D010364:Pattern Recognition, Visual; D011597:Psychomotor Performance; D011930:Reaction Time; D013067:Speech Perception