Interhemispheric transfer of kinesthetic information and line bisection task performance in patient with callosal agenesis.

Patient G.J., male, 7 yrs, with callosal agenesis, was found perfectly able to cross-replicate hand postures in right-to left and left-to-right directions. Bimanual coordination as well as touch localization and intermanual matching were performed without errors. He failed to name 2 out of 8 objects, palpated with the left hand. At the age of 13 patient performed like normal controls in line bisection task, was successful in intermanual replication of hand postures and intermanual matching while failed to name 8 out of 12 familiar objects palpated with the left hand. G.J.'s case does not support idea about bilateral presentation of language centers and development of compensatory ipsilateral afferents in patients with callosal agenesis. Presence of anterior and interictal commissures in G.J. did not contribute to the exchange of information between sensory areas of the right hemisphere and language centers of the left half brain. However, normal intermanual matching and replication of hand postures, as well as high level of line bisection task performance suggests, that anterior and/or intertectal commissure could contribute to the functional integration of sensory areas of the two hemispheres.

Disorders of visuo-spatial attention in patients with unilateral brain damage.

Visuo-spatial inattention (VSI) was examined in 390 patients with ischemic insult to the right or left cerebral hemispheres. VSI was revealed in 44 out of 80 patients with right parietal lobe damage and in 30 out of 70 subjects with right occipital lobe injury. Only one patient out of 100 with left hemisphere injury has shown the signs of VSI. These data confirm the suggestion that the right parietal and occipital regions are crucial for visuo-spatial attention, whereas the left hemisphere is of minor import.