IDENTIFICATION OF SIDE OF SEIZURE ONSET IN TEMPORAL-LOBE EPILEPSY USING MEMORY TESTS IN THE CONTEXT OF READING DEFICITS

Sixty patients with temporal lobe epilepsy were classified into readin g deficient (RD; n = 21) and non-reading deficient (non-RD; n = 39) gr oups. Selective deficits in verbal or nonverbal memory, consistent wit h side of seizure onset, were evident in the non-RD patients. Both ver bal and nonverbal memory performance were reduced equivalently in indi viduals with RD, regardless of side of seizure onset. As a result, mem ory tests that were accurate in identifying side of seizure onset in t he non-RD group were not as accurate in the RD group. When individual cases were classified using a clinically applicable decision rule, sig nificantly more RD patients were either unclassifiable or incorrectly classified than were non-RD patients. Findings suggest that preoperati ve 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 t hose obtained from patients without RD.