Relationship Between Sensory-Motor Deficits and Wais Verbal and Performance Scores in Unilateral Brain Damage

Summary Twenty-six patients with left hemisphere brain damage (LHD) and 25 patients with right hemisphere damage (RHD) were administered the WAIS and a battery of tests sensitive to sensory-motor deficits in the right and left upper extremity. The LHD group received a significantly lower VIQ than PIQ, and the opposite relationship was obtained for the RHD group. Between-group comparisons reveal significant differences between the two groups on VIQ, with the LHD group receiving the lower score, but no differences on PIQ, a finding consistent with that of other studies. The two groups differed in the expected direction on the sensory-motor tests, with the LHD group showing right sided deficits, and the RHD group showing left sided deficits. Significant relationships were found between WAIS scores and sensory-motor deficits for the LHD group, but not for the RHD group. Two possible explanations for the lack of difference between the two groups on PIQ were considered: the LHD group failed to be superior to the RHD S s on this scale because of right (preferred) hand sensory-motor impairments; or, language deficits in the LHD group impaired them on PIQ. The results appeared to support the latter hypothesis. It was further shown that WAIS scores are more influenced by sampling techniques in LHD groups than in RHD groups, a fact which may help explain some of the discrepant findings of studies in this area. When these methodological issues were considered, the results supported the hypothesis of differential functioning of the two hemispheres, including the possible mediation of “non-verbal” abilities by the right hemisphere.