Interictal EEG and Ictal Scalp EEG Propagation Are Highly Predictive of Surgical Outcome in Mesial Temporal Lobe Epilepsy
Article first published online: 2 AUG 2005
Volume 41, Issue 5, pages 564–570, May 2000
How to Cite
Schulz, R., Lüders, H.O., Hoppe, M., Tuxhorn, I., May, T. and Ebner, A. (2000), Interictal EEG and Ictal Scalp EEG Propagation Are Highly Predictive of Surgical Outcome in Mesial Temporal Lobe Epilepsy. Epilepsia, 41: 564–570. doi: 10.1111/j.1528-1157.2000.tb00210.x
- Issue published online: 2 AUG 2005
- Article first published online: 2 AUG 2005
- Accepted December 8, 1999
- Mesial temporal sclerosis;
- Temporal lobe epilepsy;
- Epilepsy surgery;
Summary: Purpose: Surgical outcome in patients with mesial temporal lobe sclerosis (MTS) is worse than that in patients with temporal lobe activity (TLE) with tumors. Previous studies of the ictal EEG focused on ictal EEG onset in scalp EEG or ictal EEG propagation in invasive recordings. Ictal EEG propagation with scalp electrodes has not been reported.
Methods: Ictal scalp EEG propagation patterns were studied in 347 seizures of 58 patients with MTS or nonlesional TLE. Interictal epileptiform discharges (IEDs) and the presence of unilateral mesial temporal lobe atrophy in magnetic resonance imaging (MRI) also were studied in these 58 patients. Fortynine patients were operated on (minimal follow-up of 1 year).
Results: Postoperatively, seizure-free outcome was seen in (a) 82.8% of patients with regionalized EEG seizure without contralateral propagation, but in only 45.5% of patients with contralateral propagation (p = 0.007); (b) 84.6% of patients with 100% IED lateralized to one temporal lobe, but in only 52.2% with <100% unitemporal IED (p = 0.015); (c) 88.9% with 100% unitemporal IED and regionalized ictal EEG combined, 73.7% with one of both variables, and only 33.3% with <100% ipsitemporal IED combined with contralateral ictal EEG propagation (p = 0.007).
Conclusions: Switch of lateralization or bitemporal asynchrony in the ictal scalp EEG and bitemporal IED are most probably an index of bitemporal epileptogenicity in MTS and are associated with a worse outcome.