EFFECTS OF DURATION OF EPILEPSY ON THE UNCOUPLING OF METABOLISM AND BLOOD-FLOW IN COMPLEX PARTIAL SEIZURES

We derived interhemispheric asymmetry indices (AIs) in interictal gluc ose uptake and blood flow in the temporal lobes of patients with intra ctable complex partial seizures from F-18 and O-15 positron emission t omograms. All patients subsequently underwent either left (n = 16) and right (n = 18) temporal lobectomy. We determined the effects on AIs o f clinical seizure variables, including duration of seizure disorder, age at seizure onset, frequency of complex partial seizures, history o f secondary generalization, history of febrile seizures, and magnetic resonance imaging evidence for mesial temporal sclerosis. Duration of seizure disorder produced the only significant effects. Degree of inte rhemispheric asymmetry in both glucose uptake and blood flow increased with duration of seizure disorder. However, the rate of increase in a symmetry was significantly greater for glucose uptake than for blood f low. These results indicate that uncoupling of metabolism and blood fl ow is a progressive process that results from the differential respons e of glucose metabolism and blood flow to chronic seizure activity. Th e results also suggest that duration of seizure disorder may be an imp ortant variable to consider in the interpretation of PET studies for e valuation of seizure surgery candidates.