Abstract Details

Title Scalp Electroencephalography and Intraoperative Electrocorticography and Temporal Lobe Epilepsy Surgical Outcomes in Patients with Normal MRI

Topic Epilepsy

Presentation(s) (-)

Poster/Presentation
Number 006

Objective

Background TLE patients with normal MRI have a higher risk of seizure recurrence after temporal lobectomy compared to patients with epileptogenic MRI lesions. Scalp EEG and ECoG are routinely used in pre-surgical evaluation of patients with medically-resistant epilepsy, but their correlation with surgical outcomes in patients with normal MRI is less clear.

Design/Methods We retrospectively identified 1585 patients from the Mayo Clinic Epilepsy Surgery Database who had epilepsy surgery for medically-resistant epilepsy between January 1990 and November 2010. A total of 87 patients met the inclusion criteria of a first-time temporal lobectomy with amygdalohippocampectomy, normal MRI, and at least 12 months of follow up. The following variables were evaluated for prognostic value: presence of bilateral independent epileptiform spikes on scalp EEG prior to surgery, epileptiform spikes on ECoG outside of the resection site, ECoG alfentanil-provoked epileptiform spikes outside of the resection site, and the location of epileptiform spikes on ECoG (mesial-only versus mesiolateral and lateral). The primary outcome was seizure recurrence defined as Engel classification II through IV. Data were collected through retrospective chart review. Univariate analysis was performed using time-to-event analysis with log-rank testing. Variables reaching significance were then analyzed with Cox proportional hazards.

Results Of the examined variables, the presence of independent bilateral epileptiform spikes on scalp EEG (p=0.001) and epileptiform spikes on ECoG outside of the resection site (p=0.016) were associated with seizure recurrence. Both remained statistically significant when evaluated with Cox proportional hazards (scalp EEG, p=0.0017; baseline ECoG, p=0.006).

Conclusions Epileptiform spikes on ECoG outside the resection site and bilateral independent epileptiform spikes on interictal scalp EEG are associated with post-operative seizure recurrence in patients with TLE and normal MRI.

Authors/Disclosures
David B. Burkholder, MD, FAAN (Mayo Clinic) PRESENTER	The institution of Dr. Burkholder has received research support from Longboard pharmaceuticals.
Jai Perumal, MD	Dr. Perumal has received personal compensation in the range of $500-$4,999 for serving as a Consultant for Genentech. Dr. Perumal has received personal compensation in the range of $500-$4,999 for serving as a Consultant for T G therapeutics. Dr. Perumal has received personal compensation in the range of $500-$4,999 for serving as a Consultant for EMD Serono.
Vlastimil Sulc	No disclosure on file
E. M. Hoffman, DO, PhD (Mayo Clinic, Neurology)	Dr. Hoffman has nothing to disclose.
Gregory D. Cascino, MD, FAAN (Mayo Clinic)	Dr. Cascino has received personal compensation in the range of $5,000-$9,999 for serving as an Editor, Associate Editor, or Editorial Advisory Board Member for International League Against Epilepsy . Dr. Cascino has received intellectual property interests from a discovery or technology relating to health care. Dr. Cascino has received publishing royalties from a publication relating to health care. Dr. Cascino has received publishing royalties from a publication relating to health care.
Jeffrey W. Britton, MD, FAAN (Mayo Graduate School of Medicine)	Dr. Britton has received personal compensation in the range of $0-$499 for serving as a Online course with American Clinical Neurophysiology Society.
Elson L. So, MD, FAAN (Mayo Clinic)	Dr. So has nothing to disclose.
	No disclosure on file
Jamie J. Van Gompel, MD	Jamie J. Van Gompel, MD has stock in Neuroone.
	No disclosure on file
Gregory A. Worrell, MD (Mayo Clinic College of Medicine)	Dr. Worrell has received stock or an ownership interest from NeuroOne Inc.. Dr. Worrell has received stock or an ownership interest from Cadence Neuroscience Inc. The institution of Dr. Worrell has received research support from NIH. The institution of Dr. Worrell has received research support from Medtronic Inc.. The institution of Dr. Worrell has received research support from Neuropace Inc,. The institution of Dr. Worrell has received research support from Epilepsy Foundation of America. Dr. Worrell has received intellectual property interests from a discovery or technology relating to health care. Dr. Worrell has received intellectual property interests from a discovery or technology relating to health care.

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