Abstracts

Rationale: The epilepsy center at King Faisal Specialist Hospital serves a population of more than 7 million. Patients with refractory epilepsy are referred to our epilepsy center for pre-surgical evaluation. Upon referral to our center, a 30-minutes EEG is usually performed as part of the initial assessment, followed by comprehensive evaluation including long term video-EEG monitoring in the epilepsy monitoring unit (EMU). The data is limited in the literature regarding the yield of doing routine EEG in this clinical settingWe aim to assess the role of routine EEG done prior to EMU evaluation in the initial assessment of patients with refractory epilepsy.  Methods: We conducted a retrospective chart review of all patients admitted to the epilepsy monitoring unit between January 2016 and December 2017.  Data collected included demographics, duration of epilepsy, seizure frequency, number of antiepileptic drugs (AEDs), seizure classification, brain MRI findings, and results of the first EEG performed in our center. Patients with incomplete data or those admitted for evaluation other than refractory epilepsy were excluded. Results: Out of 160 patients, 102 patients had complete data and were included. There were 49 men (48%), with a mean age of 25 years (range; 3-65, SD; ±12 years), and the mean duration of epilepsy was 13.8 years (range;1-40 years).Focal epilepsy was found in 87 patients (85%), generalized in 7 (7%), and unclassified in 8 (8%). Average seizure frequency was 7 per month (range 1-30 seizures). On average, 2.5 AEDs were used per patient (range; 1-5). Brain MRI was abnormal in 62 patients (61%), 26 of them (43%) had MTS.In the first routine EEG, interictal epileptiform discharges (IED) were found only in 40 patients (39%). Figure 1 showing IEDs and other variables.A multivariate regression analysis showed that for each increase in the patient’s age by one year, IEDs were 10% less likely to be seen (OR=0.9, 95%CI; 0.8-0,9, p-value 0.05), when adjusted for gender, epilepsy classification, duration of epilepsy and number of AEDs. No similar observation was noted with other variables. Conclusions: The rate of detecting epileptiform discharges on routine EEG in refractory epilepsy patients is not higher than epilepsy patients in general. A Routine EEG performed prior to EMU evaluation might be an unnecessary procedure.  Funding: None