Interictal spike frequency correlations with outcome for temporal lobe epilepsy with unilateral hippocampal sclerosis

Objective To assess the implications of the interictal spike frequency over the affected temporal lobe for temporal lobe epilepsy(TLE) with unilateral hippocampal sclerosis.Methods We retrospectively analyzed the electroencephalogram(EEG) of 33 TLE patients with unilateral hippocampal sclerosis who underwent anterior temporal resection.Preoperative 1-h interictal EEGs of wake states were evaluated for interictal spikes.Patients were catergorized according to spike frequency(frequent spike group vs.non-frequent spike group) and spike distribution(uni-temporal group vs.bi-temporal group).Patients were classified by Engle classification for 1 year at least after surgery.Fisher exact test and generalized linear models were used to analysis the relation between the interictal spikes and outcome.Results Sixteen of seventeen(94.1%) patients' seizure disappeared in frequent spike group,but only 10 of 16(62.5%) patients in non-frequent spike group(P=0.039).Duration of epilepsy,the existence of general seizure and aura is positive correlation with interictal spikes frequency.Conclusion High spike frequency is a predictor for poor outcome.