MRI-NEGATIVE TEMPORAL LOBE EPILEPSY
Abstract number :
3.199
Submission category :
Year :
2002
Submission ID :
869
Source :
www.aesnet.org
Presentation date :
12/7/2002 12:00:00 AM
Published date :
Dec 1, 2002, 06:00 AM
Authors :
Lisa M. Bateman, Paul A. Garcia, Everett J. Austin, Nicholas M. Barbaro, John A. Walker, Kenneth D. Laxer. Neurology, University of California, San Francisco, San Francisco, CA; Neurosurgery, University of California, San Francisco, San Francisco, CA
RATIONALE: Temporal lobe epilepsy (TLE) due to mesial temporal sclerosis (MTS) is a well-defined clinical syndrome with recognized clinical, physiological, and neuroimaging features. MTS is the most common pathological finding in patients undergoing temporal lobectomy for refractory TLE, and such patients have an excellent chance for seizure freedom after surgery. In patients with a normal MRI, the clinical syndrome is less well-defined, and the chances of successful surgery are reported to be lower.
METHODS: Twenty-seven consecutive patients with normal MRI scans (MRI-NEG) who underwent temporal lobectomy for refractory TLE were retrospectively identified. Their clinical, electrophysiological, neuropsychological, neuroradiological and neuropathological characteristics were compared with patients having MRI evidence of MTS (MRI-MTS) matched for age, sex, and side of surgery. All patients had at least one year of post-operative follow-up, with outcomes defined using Engel[ssquote]s classification.
RESULTS: MRI-NEG patients had later seizure onsets (19.3 years versus 11.1 years) and shorter duration of seizures prior to surgery (13.2 years versus 21.7 years) than MRI-MTS patients. MRI-NEG patients were more likely to be employed than MRI-MTS patients. There were no differences in epilepsy risk factors, seizure semiologies, electrophysiological findings or ancillary neuroimaging data between the groups. MRI-NEG patients were more likely to have pathologic diagnoses other than gliosis or MTS, or to have multiple pathologies, than MRI-MTS patients. 63.0% of MRI-NEG patients and 74.1% of MRI-MTS patients were seizure free after surgery (Engel Class 1).
CONCLUSIONS: MRI-negative TLE is distinguished from TLE with MRI evidence of MTS by later seizure onset, shorter duration of epilepsy prior to surgery, and more diverse pathological findings at the time of surgery. Temporal lobectomy should still be considered in these patients, even though the chance of a good surgical outcome may be lower than in patients with MRI evidence of MTS.
[Supported by: This work was supported by NIH grant RO1-NS31966.]