Abstracts

Rationale: The Human Epilepsy Project (HEP) is a multicenter prospective observational study of focal epilepsy patients aged 12-60 years with less than 4 months of AED treatment at enrollment. The study's primary objective is to identify predictors of treatment resistance and co-morbid conditions; EEG, imaging, blood, urine, and behavioral measures are being explored as candidate biomarkers toward this end. Methods: A history of clinical seizures consistent with focal epilepsy was required for inclusion. Progressive or acquired lesions or known genetic syndromes were among key exclusion criteria. A panel of HEP epilepsy specialists confirmed eligibility. A baseline digital EEG of at least 20 minutes duration was required; longer EEGs were encouraged if this EEG was normal. We collected raw EEG data and interpretations from the first 78 participants spanning 22 sites, which were reviewed by members of the HEP EEG core. Results: A total of 28 focal seizures were recorded on baseline EEGs in 16/78 (21%) of participants; 4 patients had multiple seizures. 13 EEGs were clinical EEGs lasting more than 2 hours, 2 were HEP protocol EEGs lasting 2 hours or less, and 1 was a clinical EEG lasting less than 1 hour. Of the 28 focal seizures, 20 were recorded during wakefulness. Seizure duration ranged from 15 seconds to 149 seconds (mean 76 seconds). Scalp EEG ictal localization was temporal (57%), non-localized (29%), or frontal (14%). Overall, 38 of 78 (49%) participants had epileptiform findings on their baseline EEG: 22 had interictal discharges alone while 16 had seizures; 4 had both seizures and interictal discharges. Conclusions: Initial EEG data from HEP demonstrates that 21 percent of the first 78 patients had focal seizures recorded on their EEGs, the majority of which were clinical EEGs lasting more than 2 hours. These findings suggest that EEG yield may be higher than previously believed when applied to carefully phenotyped cohorts, and that extending EEG duration beyond routine parameters may assist in diagnosis. Further longitudinal study of our cohort may yield information on the prognostic value of an epileptiform baseline EEG with respect to treatment resistance and development of co-morbid conditions. Sources of funding: The Epilepsy Study Consortium (ESCI) is a non-profit organization dedicated to accelerating the development of new therapies in epilepsy to improve patient care. The funding provided to ESCI to support HEP comes from industry, philanthropy and foundations (UCB Pharma, Finding A Cure for Epilepsy and Seizures, Pfizer, Lundbeck, The Andrews Foundation, Friends of Faces and others).