Functional asymmetry of the human brain.

Verbal and nonverbal memorization skills were tested before and after electroconvulsive shocks to the left, right, or both cerebral hemispheres of neurologically normal patients. As predicted, decrements for the left-hemisphere-shocked group were larger on the verbal than nonverbal tasks, while the reverse was true for the right-hemisphere-shocked group. Largest decrements on both tasks were shown by the bilaterally shocked group.