Abstracts

Rationale: Genetic generalized epilepsy (GGE) syndromes affect approximately 20% of all patients with epilepsy, predominantly younger age groups. While GGE typically has a more favorable prognosis compared to many other epilepsy syndromes, patients who are medically refractory have few options available to them. There are currently no clinical characteristics widely accepted in the literature as predictive of drug resistance. Similarly, while EEG is crucial in making the initial diagnosis of GGE, studies investigating EEG predictors of refractoriness have had variable results. Despite this, many epileptologists utilize EEG features, for example, the overall abundance of generalized epileptiform discharges as prognostic indicators. Our study aims to identify potential EEG markers differentiating medically refractory versus responsive patients. Methods: We retrospectively identified all patients treated at the Columbia University Comprehensive Epilepsy Center with a treating clinician diagnosis of GGE. We then reviewed the medical chart data and categorized patients into two groups: medically refractory (defined as patients with ongoing seizures despite two adequate trials of antiepileptic medications) and medically responsive. One reviewer (BK) then reviewed the first available EEG recording (including both routine and long-term studies) for each patient and recorded characteristics we hypothesized could potentially predict a medically refractory course, including quantification of generalized epileptiform discharges based on the ACNS Critical Care EEG Terminology guidelines. Results: There were 126 patients identified in the medically refractory group and 547 patients in the medically responsive group. Of the 126 medically refractory patients, 66 (M=23, F=43, mean age 33 years, age range 8-86 years) had EEG available for review. 80.3% (53/66) of the medically refractory group had generalized epileptiform discharges. 69.7% of them (46/66) had generalized discharges in wakefulness (burden: abundant 13.2%, frequent 36.8%, occasional 42.1%, and rare 7.9%). Sleep was captured in 52/66 of the refractory patients, with 76.9% (40/52) having generalized discharges in sleep (burden: abundant 21.9%, frequent 46.9%, 21.9%, and rare 9.4%). Eight patients (12.2%) also had generalized paroxysmal fast activity. Further analysis of the medically responsive patients is pending and will be presented, in addition to statistical comparisons of the two groups<./p>