The Utility of Intracranial Electroencephalography During Non-Awake Craniotomy to Predict Tumor-Related Epilepsy
Abstract number :
3.137
Submission category :
3. Neurophysiology / 3C. Other Clinical EEG
Year :
2018
Submission ID :
506824
Source :
www.aesnet.org
Presentation date :
12/3/2018 1:55:12 PM
Published date :
Nov 5, 2018, 18:00 PM
Authors :
Thomas Wychowski, University of Rochester; James Fessler, University of Rochester; Gregory A. Worrell; Benjamin H. Brinkmann; Kevin Walter, University of Rochester; Nimish Mohile, University of Rochester; and Gretchen L. Birbeck, University of Rochester
Rationale: Patients with supratentorial CNS tumors are at high risk of developing tumor-related epilepsy (TRE) during their treatment course. Despite this risk, routine prophylaxis with antiepileptic drugs (AEDs) in seizure-naïve patients is not recommended by the American Academy of Neurology (AAN) due to lack of efficacy, adverse effects and drug-drug interactions with anti-cancer drugs. Since the release of this AAN guideline in 2000, the advent of newer, more tolerable AEDs poses the question of whether the value of AED prophylaxis in this population should be re-evaluated. The success of future AED TRE prophylaxis trials may require the identification of markers of high TRE-risk. Intracranial encephalography (iEEG) could provide a candidate marker for increased epileptogenicity in this population and was recently shown to be a useful measure of epileptogenicity in gliomas during awake tumor surgery (Neurology 2018;90:e1119-e1125). Most patients undergoing tumor resection do not require an awake craniotomy for mapping of eloquent cortex. This study aimed to evaluate for epileptiform discharge or high-frequency oscillation (HFO) activity in iEEG acquired during non-awake craniotomy. Methods: New patients with supratentorial tumors were recruited to participate in this single-center pilot study at the University of Rochester between 11/2014 -7/2016. iEEG was acquired during standard tumor resection surgery using an anesthesia protocol prescribed specifically for non-awake iEEG recording. Baseline clinical, radiographic and histopathologic data were collected. Subjects were followed clinically for 1 year for seizure outcome. iEEG was evaluated for epileptiform discharge activity and HFOs both visually and with an automated HFO detector. Results: Eleven subjects were recruited (4 with grade 4 astrocytoma, 4 with grade 3 astrocytoma, 1 with grade 2 astrocytoma, 1 with grade 2 meningioma, and 1 with grade 1 ganglioglioma). Six subjects experienced seizures prior to surgery. Comparing subjects with preoperative seizures to those without, there was no difference in expression of epileptiform discharge activity (respectively, 3 of 6 vs 3 of 5, p = 1) or HFO activity (respectively, 1 of 6 vs 2 of 5, p = .55). One of 5 subjects without preoperative seizures later developed TRE and exhibited epileptiform discharge and HFO activity on iEEG. One subject never having experienced a seizure also demonstrated epileptiform discharge and HFO activity on iEEG. An isocitrate dehydrogenase (IDH-1) mutation was expressed in tumors of 3 subjects with astrocytoma, none of which exhibited epileptiform discharge or HFO activity. When present, HFO activity was rarely observed independent of epileptiform discharge activity. Conclusions: In this small pilot/feasibility study, epileptiform discharge and HFO activity were commonly seen during iEEG recordings during non-awake craniotomy for tumor resection. There was no statistical association between epileptiform discharge or HFO activity and seizure history or IDH-1 mutations status. Funding: Neurology Pilot Program - Department of Neurology, University of Rochester