S179. The incidence of first seizures, new diagnosis of epilepsy and seizure mimics in county cork, Ireland; an Epidemiologic protocol and interim report

Abstract

Introduction Incidence studies provide valuable information on etiology and natural history of epilepsy wihtin a population. The International League Against Epilepsy (ILAE) has proposed standards for epidemiological studies to ensure rigorous methodology and accurate collection of data ( Thurman et al., 2011 ). The incidence of epilepsy has not been investigated in Ireland. We are currently investigating the incidence of first seizures, new diagnosis of epilepsy and seizure mimics in Cork city and county (population estimate 550,000) over the calendar year 2017 incorporating ILAE guidelines and seizure/epilepsy classifications ( Fisher et al., 2017 , Scheffer et al., 2017 ). Methods We applied multiple overlapping methods of case ascertainment to our study population from January 1st 2017 to identify all patients presenting with suspected first seizure or new diagnosis of epilepsy. Neonatal seizures and febrile seizures are excluded. Case ascertainment methods include daily review of emergency department (ED) triage, radiology, EEG databases, neurology outpatient/inpatient departments, neurosurgical ward, geriatrics wards, oncology wards, paediatric services and community surveillance through survey of general practice and residential care facilities. Results Two hundred and sixty-three cases met our inclusion criteria for the first three months of data collection (Jan-Mar 2017). EEG database review yielded the greatest number of novel cases (n = 60). 26% (n = 69) of cases met criteria for definite new diagnosis of epilepsy. Only 25 % (n = 16) of these had epileptiform abnormalities on routine EEG. The majority of cases were classified as focal epilepsy (75%, n = 52) followed by generalized epilepsy (16%, n = 11) and unknown epilepsy type (9%, n = 6). 40% (n = 114) of identified cases were classified as seizure mimics. Conclusion We present a rigorous study protocol, which is adherent to ILAE recommendations, for the investigation of the incidence of first seizures, new diagnosis of epilepsy and seizure mimics in our study population and present interim results for the first three months of data collection with an emphasis on neurophysiological findings. Results demonstrate a greater proportion of focal epilepsy syndromes than previously reported, which may be in part due to application of the updated ILAE epilepsy classification system.