To identify factors influencing outcome and morbidity in patients selected for corpus callosotomy, we retrospectively reviewed 23 patients with intractable generalized seizures who underwent corpus callosotomy between 1991 and 1994. Three patients had a complete corpus callosotomy, while 20 had an anterior callosotomy. Three of those patients subsequently had completion of the anterior callosotomy. Overall, 41% of patients were nearly or completely free of the seizure types targeted for surgical treatment, while another 45 % had seizures less than half as frequently. Four patients developed simple partial motor seizures after callosotomy. A transient disconnection syndrome was observed in 57% of patients. The best predictor of good outcome was a normal preoperative MRI. Mentally retarded patients had poorer outcomes. Outcome was not predicted by extent of callosal section or lateralization on neurological examination, EEG, MRI, and SPECT. Completion of anterior callosotomy resulted in significant reductions in seizure frequency. Though most patients do not become seizure-free after corpus callosotomy, worthwhile palliation of an otherwise intractable illness can be achieved. An analysis of prognostic factors should lead to better selection of patients for surgery.

Sixty patients with temporal lobe epilepsy were classified into reading deficient (RD; n = 21) and non-reading deficient (non-RD; n = 39) groups. Selective deficits in verbal or nonverbal memory, consistent with side of seizure onset, were evident in the non-RD patients. Both verbal and nonverbal memory performance were reduced equivalently in individuals with RD, regardless of side of seizure onset. As a result, memory tests that were accurate in identifying side of seizure onset in the non-RD group were not as accurate in the RD group. When individual cases were classified using a clinically applicable decision rule, significantly more RD patients were either unclassifiable or incorrectly classified than were non-RD patients. Findings suggest that preoperative memory data obtained from individuals with epilepsy and evidence of RD may not be as valid an indicator of side of seizure onset as are those obtained from patients without RD.