Abstracts

Rationale: In the setting of concordant clinical history, interictal epileptifom abnormalities can make the correct diagnosis of epilepsy, in most of the patients. However, routine EEG, which is usually less than 40 minutes, has low sensitivity with a wide range between 25-56%. It is plausable that the longer recordings with activation procedures would disclose epileptiform abnormailites though there is no study to compare 30-minute recordings with sleep deprivated 2-hour sleep recodings in the setting of outpatient clinics. The objective of the study is to find out an optimal length of the EEG recording to strength of the diagnosis of epilepsy. Thus, we compared 30-minute routine EEG and 2-hour sleep deprivated sleep EEG according to their interictal epileptiform abnormalities.Methods: Total of 323 patients with epilepsy (ages between 14-76, with average age of 33.9 and 56.1% of them were women) who were evaluated at outpatient Neurology clinic in Istanbul Medipol University between June 2013 and June 2014 were retrospectively rewieved. All of the patients had at least two suspicious attacks with loss of consciousness in their history and they all were eventually diagnosed with ""epilepsy"" based on the clinical features, brain MRI findings and other test results that excludes differential daignosis. Of all patients, 269 had 30-minute EEG and 54 had 2-hour sleep EEG (with minimum duration of 10-minute stage 2 sleep) for as a first diagnostik tool. None of the patient were under antiepileptic medications. After the diagnosis, they all were started on antiepileptic treatment. In this pilot study, routine and 2-hour sleep EEG data, as well as their brain MRI findings were evaluatedResults: Initial routine (30-minute) EEG in 269 patients revealed epileptiform abnormailty in 47 of them (18%): However, 2-hour sleep deprivated sleep EEG as a fist diagnostic test did reveal epileptiform abnormality in 23 of 54 patients (43%). Fifty-six patients of routine EEG group (n=269) had brain MRI results and 34 of them had (60.7%) some abnormalities in their reports though only 6 of them (17.6%) had concordant EEG and MRI abnormalities. All of the patients in 2-hour sleep EEG group (n=54) had brain MRI and 25 of them (%83.3) had MRI abnormality and of those abnormal ones only 4 (%16) had concordant EEG and imaging results.Conclusions: We found sleep deprivated 2-hour sleep recordings are at least 2-fold superior than 30-minute routine EEG recordings in outpatient settings. Although the two group had different number of cases, the study is still going on and the results are presented as pilot data. It is very well known that the long term video/EEG monitoring is more beneficial to disclose epileptiform abnormalities and it is correlated wıth the length of the recordings. In the outpatient settings, it seems that 2-hour sleep EEG recordings are the best plausible method for the initial diagnosis of epilepsy. This study highlights the efficacy of sleep deprivated 2-hour sleep recordings in the initial diagnosis of epilepsy. This method should be preferred particularly for patient with diagnostic dilemma..