Fifty nonspeaking or minimally speaking subjects with moderate, severe, or profound mental retardation underwent evaluation of handedness. Results confirmed increased prevalence of non-right handedness and the occurrence of a large subtype of ambiguous handedness. Results suggest that incidence of atypical hand preference is not closely linked to…

This study of 34 adults with Down's syndrome found that right-handed subjects exhibited no lateral advantage in dihaptic shape-matching, whereas left-handed subjects displayed an expected left-hand advantage. In a visual field dot enumeration task, both groups exhibited left-field superiority. Results indicate that subjects' atypical cerebral…

Twenty-four adults with mild mental retardation were compared with equal-mental age children and adults without mental retardation on tactile processing asymmetries. Results suggest that hemispheric processing is dependent on information processing requirements rather than type of stimulus. (Author/JDD)