INTRODUCTION: Detection of epileptiform discharges often requires serial EEGs. Attaining early diagnosis may help in early intervention in patients with epilepsy. This study aimed to evaluate the added value of sleep in terms of detection of epileptiform features or change in background activity on EEG. Thus, helping to ensure early diagnosis in a cost-effective manner.

METHODS: It was a cross-sectional study which included EEG recordings of children aged 6 months to 18 years, performed between August 2017 and May 2018. EEGs lacking at least 30 minutes of recording were excluded from the study. Epileptiform discharges in wakefulness and sleep were compared. Additional yield of sleep was considered if any of the following findings was observed: appearance or increase of epiletiform activity, change in localization or morphology, and appearance of generalization during sleep recording.

RESULTS: Out of total 160 analyzed recordings 79 sleep and wakefulness records showed abnormalities (mean age 6.68, SD 4.54). Of them 71.1% EEGs that lacked epileptiform discharges on wakefulness presented with additional yield on sleep ( p value <0.003 chi square) while 72.2% EEGs showing epileptiform activity during wakefulness showed further increased discharges during sleep (p value < 0.003 chi square). While sleep had little effect on background activity changes.

CONCLUSION: When wakefulness EEGs lack epileptiform activity sleep effectively increases the yield of epileptiform discharges in pediatric population. Thus, sleep EEGs should be considered as a part of routine EEGs for pediatric population.