Usefulness of a simple sleep-deprived EEG protocol for epilepsy diagnosis in de novo subjects

•We assessed retrospectively the role of a simple method of EEG after sleep deprivation (SD-EEG) on a large population of de novo patients evaluated for suspected seizures, bearing a normal basal EEG.•In these patients SD-EEG often reveals interictal abnormalities and bears a high specificity in epilepsy diagnosis.•Interictal abnormalities are different in generalized versus focal epilepsies, and in the latter the interictal abnormalities yield in SD-EEG is higher than in a repeated routine EEG.

ObjectiveIn case series concerning the role of EEG after sleep deprivation (SD-EEG) in epilepsy, patients’ features and protocols vary dramatically from one report to another. In this study, we assessed the usefulness of a simple SD-EEG method in well characterized patients.MethodsAmong the 963 adult subjects submitted to SD-EEG at our Center, in the period 2003–2010, we retrospectively selected for analysis only those: (1) evaluated for suspected epileptic seizures; (2) with a normal/non-specific baseline EEG; (3) still drug-free at the time of SD-EEG; (4) with an MRI analysis; (5) with at least 1 year follow-up. SD-EEG consisted in SD from 2:00 AM and laboratory EEG from 8:00 AM to 10:30 AM. We analyzed epileptic interictal abnormalities (IIAs) and their correlations with patients’ features.ResultsEpilepsy was confirmed in 131 patients. SD-EEG showed IIAs in 41.2% of all patients with epilepsy, and a 91.1% specificity for epilepsy diagnosis; IIAs types observed during SD-EEG are different in generalized versus focal epilepsies; for focal epilepsies, the IIAs yield in SD-EEG is higher than in second routine EEG.ConclusionsThis simple SD-EEG protocol is very useful in de novo patients with suspected seizures.SignificanceThis study sheds new light on the role of SD-EEG in specific epilepsy populations.