Predictive Value of Electrocorticography in Patients with Temporal Lobe Epilepsy and Normal MRI
Abstract number :
3.192
Submission category :
Year :
2001
Submission ID :
2010
Source :
www.aesnet.org
Presentation date :
12/1/2001 12:00:00 AM
Published date :
Dec 1, 2001, 06:00 AM
Authors :
L.M. Bateman, MD, Neurology, UCSF, San Francisco, CA; T.M. Al Saadi, MD, Neurology, UCSF, San Francisco, CA; K.D. Laxer, MD, Neurology, UCSF, San Francisco, CA; P.A. Garcia, MD, Neurology, UCSF, San Francisco, CA; E.J. Austin, MD, Neurology, UCSF, San Fra
RATIONALE: To study the value of electrocorticography (ECoG) in predicting surgical outcomes in patients with temporal lobe epilepsy and normal magnetic resonance imaging studies.
METHODS: We restrospectively identified patients with temporal lobe epilepsy who had normal MRI scans as part of their presurgical evaluations. For each patient, we reviewed clinical and video-EEG telemetry data, neuroimaging studies, electrocorticography findings and surgical outcomes. Patients were classified based on the prevalence of spikes in either a lateral neocortical or an amygdalo-hippocampal distribution on pre-excisional ECoG recordings. A separate analysis was performed based on the presence or absence of any epileptiform activity on post-excisional ECoG recordings. Groups were compared by surgical outcome using Engel classification at one year post-surgery. Statistical analysis was performed with Fisher[ssquote]s exact test.
RESULTS: Twenty-eight patients were identified, ages 11-50 (mean 30.7) with seizure durations 3-46 years (mean 19.3). All patients had video-EEG telemetry to confirm temporal lobe seizure onsets prior to surgery. All patients underwent a standard anteromedial temporal resection with pre-excisional and post-excisional ECoG. At one year post-surgery, eighteen patients were free of seizures (Engel Class 1), while ten patients were not seizure-free (Engel Class 2, 3 or 4). The distribution of spikes on pre-excisional ECoG recordings did not correlate with post-operative seizure outcome. The presence or absence of spikes on post-excisional ECoG was also not predictive of outcome.
CONCLUSIONS: Electrocorticography findings in patients with temporal lobe epilepsy and normal MRI scans do not correlate with surgical outcomes. Further studies with larger populations may help to clarify the role of ECoG in these patients.
Support: Supported by NIH Grant R01-NS31966.