Prognostic implications of absolute spike frequency over the affected temporal lobe and relative spike distribution between the two temporal lobes for postoperative seizure control were assessed in 55 adult patients with medically refractory mesial temporal lobe epilepsy (MTLE), in a study at General Hospital Hietzing, Vienna, Austria. Age at seizure onset was 11.2 +/- 9.3 years, and age at evaluation was 34.7 +/- 8.1 years. Presurgical evaluation included prolonged video-EEG monitoring. One year following surgery, 4 of 14 patients (28.6%) in the frequent spike group (>60/hr over the affected temporal lobe) were completely seizure free compared to 33 of 41 patients (80.5%) in the nonfrequent spikes group (<60/hr) (p=0.001). In the unitemporal group (>90% spikes over the affected temporal lobe), 25 of 35 patients (71%) were completely seizure free compared to 12 of 20 patients (60%) in the bitemporal spike group (p=0.282). Relative spike distribution over the two temporal lobes was not significantly related to postoperative outcome. 
COMMENT. Absolute spike frequency over the affected temporal lobe, but not relative spike distribution between the two temporal lobes, is a strong predictor of postoperative seizure control in young adults with medically refractory mesial temporal lobe epilepsy. TLE patients with a low spike frequency over a unilateral hippocampal atrophy should be excellent candidates for epilepsy surgery.