Hemispheric disconnection syndrome with a "crossed avoiding" reaction in a case of Marchiafava-Bignami disease.

A clinicopathological study is presented of a case of Marchiafava-Bignami disease with a hemispheric disconnection syndrome, an association that does not appear to have been reported previously. Gross and microscopic examination of the brain revealed necrosis of the corpus callosum (sparing a small area in front of the splenium) and of the anterior commissure, cortical and subcortical infarction of the right lingual gyrus, diffuse cortical lesions of the laminar sclerosis type, and lacunae in the basal ganglia and the pons. The patient was unable to grasp objects presented to the right visual half-field with the left hand, or to respond to contralateral somaesthetic stimuli with either of the upper limbs. This motor inhibition, with the associated extended posture, is described as a "crossed avoiding reaction", and attributed to the inability of one hemisphere to respond to visual or somaesthetic stimuli projected to the other hemisphere. Clinicopathological correlations and visuomotor coordination mechanisms are discussed in the light of previous clinical and experimental studies. Anomia to pictures projected tachistoscopically to the left visual field, disturbances in the transfer of somaesthetic information, left sided ideomotor apraxia with agraphia, right sided dyscopia, and ideational apraxia especially marked in the right visual field were observed.