[Homolateral and controlateral disturbances in the tactile discrimination of the hemispheric lesions]

Ten normal controls and 45 brain-damaged patients, affected by lesions of the right (N = 25) or of the left (N = 20) hemisphere were given a test of two points discrimination, in order to check the hypothesis of a different organization of the somesthetic function at the level of the dominant and of the minor hemisphere. Somatosensory thresholds were measured at the level of the back of the hands and of the back of the feet by means of a modified version of the Weber two-point aesthesiometer. When patients with lesions of the right and of the left hemisphere were compared the following results were obtained: --somatosensory thresholds were higher on the contralateral than on the ipsilateral side of the body in both groups of patients; --ipsilateral defects were found in about 20% of the brain-damaged patients, but no relationship was put in evidence between laterality of lesion and ipsilateral sensory defects.