Abstracts

Recent reports have suggested a possible therapeutic role of direct electrical stimulation of the hippocampus in temporal lobe epilepsy., Two adults with intractable focal seizures arising independently from both temporal lobes underwent bilateral continuous hippocampal stimulation using quadripolar electrodes implanted stereotaxically (185hz, 90[italic]u[/italic]sec, 2.6-4V). Stimulation was double blind, on or off for 3 months with a 3 month washout period. Seizure frequency and memory were assessed after each 3 month epoch., There was no implantation effect. During bilateral hippocampal stimulation, monthly seizure frequency decreased by 34% (ANOVA, p=0.006) in patient A and 26% in patient B (p=0.7). For 3 months after stimulation was off, seizures were still decreased by 26% and 20% in the two patients before returning to baseline. Subjective and objective memory assessments revealed no significant change during or after stimulation., Impact of stimulation on seizures was definite but marginal. The effect on seizures persisted after stimulation stopped. The absence of effect on memory raises questions about the role of mesial temporal structures in memory processing.,