Cognitive abilities following right and left hemispherectomy

Summary Cognitive abilities were investigated in three patients with hemispherectomy for noninfantile disease. Two had the right and one had the left hemisphere removed. Results indicate that after right hemispherectomy in the mature brain the left hemisphere remains decidedly more proficient in verbal than nonverbal functions. In the developing younger brain, however, regardless of which hemisphere was removed, less difference exists between abilities in verbal and nonverbal functions, and level of performance is in general lower than in the adult case. Memory functions were impaired after hemispherectomy with removal of the left hemisphere producing the greater deficit.