Somesthetic disconnection syndromes in patients with callosal lesions.

Somesthetic disconnection syndromes were investigated in relation to the sites of lesions in the corpus callosum in 3 patients with callosal lesions, in order to identify the callosal regions responsible for the interhemispheric transfer of somesthetic information. Cases 1 and 2 with lesions in the posterior truncus exhibited transfer deficits of discriminative sensations between the left and right hands, left-sided tactile anomia and left-sided somesthetic alexia. Case 3 with lesions in the posteroventral part of the posterior truncus showed no signs of somesthetic disconnection syndromes. The results suggest the importance of the anterior and/or dorsal part of the posterior truncus of the corpus callosum for interhemispheric transfer of the discriminative sensations and integrated somesthetic information necessary for tactile naming and somesthetic reading. Copyright 2000 S. Karger AG, Basel