Value of Interictal and Ictal Scalp-Sphenoidal EEG Data for Predicting Seizure Freedom Following Surgery for Intractable Temporal Lobe Epilepsy.
Abstract number :
H.04
Submission category :
Year :
2001
Submission ID :
203
Source :
www.aesnet.org
Presentation date :
12/1/2001 12:00:00 AM
Published date :
Dec 1, 2001, 06:00 AM
Authors :
G.J. Brekelmans, MD, PhD, Clinical Neurophysiology, SEIN, Heemstede, Netherlands; B. Jocic, MD, Child Neurology, University of Nis, Nis, Yugoslavia; W. van Emde Boas, MD, PhD, Clinical Neurophysiology, SEIN, Heemstede, Netherlands
RATIONALE: Interictal and ictal scalp-sphenoidal EEG studies are crucial for presurgical focus localization. The best surgical results are presumed to be obtained in patients in whom all presurgical investigations are congruent and indicate a single epileptogenic zone. A recent study (1) suggested that a switch of lateralization of ictal activation in temporal lobe patients indicated bitemporal epileptogenicity and predicted worse surgical outcome. Our study aimed to reassess this issue.
METHODS: We assessed the predictive value for surgical outcome of (dys)congruent interictal slowing and epileptiform discharges and of localization and lateralization of ictal activity as well as the spreading patterns including the existence of a switch in lateralization in subjects with temporal lobe epilepsy. Scalp EEG[scquote]s of 100 patients, who had undergone temporal lobe resections for medically intractable seizures were assessed retrospectively. 50 patients had a histologically proven MTS while 50 patients had a lesion, in 40 patients without a concomitant MTS. EEG[scquote]s were recorded using the 10% system with the routine use of sphenoidal electrodes.
RESULTS: 34 MTS patients and 33 lesional patients were seizure free (UCLA 1) (NS). 10 Of the 67 seizure free patients and 8 of the 33 non seizure free pts had discongruent interictal findings (NS). Propagation to the contralateral side was found in 17 sz free and 11 non sz free pts. (NS). A switch of maximal ictal lateralisation was seen in only 8 patients in the sz free group and in 6 in the non sz free group (NS).
CONCLUSIONS: These results show no statistically significant differences for interictal and ictal EEG parameters between sz free and non sz free patients. Contralateral involvement in temporal lobe epilepsy thus need not imply worse prognosis for surgical outcome.
1 Schulz R, Lüders HO et al. Interictal and ictal scalp EEG propagation are highly predictive of surgical outcome in mesial temporal lobe epilepsy. Epilepsia 2000;41(5):564-570