Abstracts

Rationale: Sudden unexpected death in epilepsy (SUDEP) is a leading cause of epilepsy-related mortality, yet the means to determine SUDEP risk in an individual patient are lacking. The SUDEP-7 inventory, a scale derived from a large prospective cohort study of SUDEP, has been utilized by some investigators as a measure of SUDEP risk. Peri-ictal physiologic measures, including post ictal generalized electroencephalographic suppression (PGES) and abnormal heart rate variability, have been associated with increased risk of SUDEP based on the SUDEP-7 inventory. However no studies to date have evaluated the reliability of this instrument. We examined whether the SUDEP-7 inventory could distinguish between cases of SUDEP and matched controls and whether PGES was more commonly observed in patients with SUDEP. Methods: We retrospectively examined 16 cases of definite or probable SUDEP and 48 living controls, matched for gender, age within 10 years and epilepsy syndrome, from the Columbia University Medical Center databases. We calculated SUDEP-7 scores and reviewed video-EEG recordings for evidence of PGES with any recorded seizure. Results: Each group consisted of 50% men and 50% women. Mean age was 42 years (range 18-63) in the SUDEP group and 41 years (range 10-73) in the control group. Mean duration of epilepsy was 24 years (range 3-48) in the SUDEP group and 21 years (range 0.25-45) in the control group. In the SUDEP group, 13 patients (81%) had a localization related epilepsy, four (30%) of whom had surgical resections, one (6%) had primary generalized epilepsy and two (13%) had an undetermined epilepsy syndrome. In the control group, 40 (83%) had localization related epilepsy, six of whom (15%) had surgical resections, five (10%) had primary generalized epilepsy and three (6%) had an undetermined epilepsy syndrome. There was no significant difference in age, duration of epilepsy, or epilepsy syndrome between the SUDEP and control groups (P = 0.72, 0.48 and 0.13 respectively). The mean SUDEP-7 score for the SUDEP group was 3.6 (range 0-9), compared with 4.2 (range 0-10) in living controls. This difference was not significant (P= 0.39). Seven patients in the SUDEP group had ictal electrographic data available for review. PGES was present in any seizure in three of these patients (43%). Thirty-seven control patients had electrographic data available for review. PGES was present with any seizure in six patients (16%). This difference was not significant (P= 0.11). Conclusions: The SUDEP-7 inventory may not be a reliable instrument to identify those at highest risk for SUDEP. Additionally, PGES was not more commonly observed in patients with SUDEP. These findings highlight the need for an improved understanding of SUDEP epidemiology and pathophysiology to better guide risk determination and prevention measures.