Speech lateralization in deaf populations: evidence for a developmental critical period.
Cerebral lateralization for speech in right-handed normal hearing and deaf adolescents was assessed using the dual-task paradigm. Subjects with normal hearing and deafness acquired after 3 years of age displayed left hemispheric dominance for speech production, whereas both congenitally deaf and those with an early acquired deafness (onset 6-36 months) showed atypical, anomalous cerebral representation. These results suggest the presence of a developmental critical period for cerebral lateralization during which exposure to adequate environmental stimulation may be needed to activate left hemispheric dominance for speech.
Marcotte
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AC
Department of Psychiatry and Human Behavior, Brown University Program in Medicine, RI.
Morere
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DA
D000293:Adolescent; D000328:Adult; D001288:Attention; D003423:Critical Period, Psychological; D003638:Deafness / Q000523:psychology*; D004292:Dominance, Cerebral; D007839:Functional Laterality; D006801:Humans; D007805:Language Development Disorders / Q000523:psychology*; D011597:Psychomotor Performance; D013067:Speech Perception