Association of Interictal Epileptiform Discharges with Sleep and Anti-Epileptic Drugs

Abstract

Background: The presence of interictal epileptiform discharges (IEDs) in electroencephalogram (EEG) is diagnostic of epilepsy. Latent IEDs are activated during sleep. Anti-epileptic drugs (AEDs) improve sleep. AEDs, sleep, and IEDs may interact and affect epilepsy management. Purpose: To explore the occurrence of IEDs and its association with sleep and AED status in suspected patients of epilepsy. Methods: EEG records were collected of suspected patients of epilepsy who reported to the electrophysiology laboratory of a tertiary care hospital during 1 year. The anthropometric details, clinical presentations, and AED status of the patients were recorded from the EEG records. Patients were divided into 2 categories based on whether AEDs had been started prior to the EEG evaluation (category-I) or not (category-II). The occurrences of IEDs in EEG recordings in both categories were analyzed. Results: In 1 year, 138 patients were referred for diagnostic EEG evaluation. One-hundred-two patients fulfilled the inclusion criteria, of which 57 patients (53%) belonged to category-I and 45 patients (47%) belonged to category-II. Incidence of IEDs, suggestive of definite diagnosis of epilepsy in category-I was 88% and in category-II was 69%, and this difference was statistically significant (p = 0.02). Conclusion: The increased proportion of IEDs in category-I patients may be due to high clinical suspicion or compounding interaction of AEDs and sleep. More extensive studies are required to delineate the complex interaction of AEDs, sleep, and IEDs so that judicious yet prompt management of epilepsy can be carried out.