Roy M. Hamlin

Intellectual function 14 years after frontal lobe surgery.

Summary Preoperative measures of intelligence are compared with retests 8 and 14 years after frontal lobe surgery. All 5s were chronic psychotics at the time of the first tests. The long-term retests are reported for 33 nonoperated controls, for 16 patients with lower frontal lobe surgery (Orbital Topectomy) and for 18 patients with upper frontal lobe surgery (Superior Topectomy). Previous research showed that both groups of operated patients scored lower on intelligence tests shortly after surgery than they did before. The objectives of the long-term retests concerned: (1) the permanence of changes, and (2) the differential effects of lower and upper forebrain surgery. The lower forebrain patients obtain long-term scores remarkably comparable to those of the nonoperated controls. The Superior Topectomy patients show significant loss 8 years after surgery, and this loss persists 14 years after surgery. The loss is both permanent and appreciable, equivalent to some 10 points in I.Q. Verbal and numerical tests reflect the permanent loss more clearly than perceptual and construction tests. The loss associated with upper frontal lobe surgery involves sustained attention, problem solving, and other intellectual functions.