Abstracts

Rationale: There are conflicting reports in the literature on the impact of rapid eye movement (REM) sleep on seizures. If REM sleep exhibits an antiepileptic effect, then this may be exploited to therapeutic advantage. Understanding this phenomenon may also provide insights into underlying pathophysiologic mechanisms behind epilepsy and REM sleep.Methods: Studies were included for systematic review if patients were clearly classified into either a focal or generalized epilepsy syndrome. Patients must have undergone EEG recording via the 10-20 system and PSG recording for appropriate scoring of sleep stages. Focal and generalized seizure rates were extracted and/or calculated for each sleep stage.Results: We reviewed 42 distinct conventional and intracranial studies (total 1458 patients). Only 1% of 1990 focal seizures in 542 patients over 9 studies occurred in REM sleep. Compared to rates in stage N1 sleep, there were 87.25 times less focal seizures, 1.57 times less focal interictal discharges, and 3.11 times less generalized seizures in REM sleep. Compared to stage N2 sleep, there were 67.84 times less focal seizures, 1.69 times less focal interictal discharges, and 3.13 times less generalized seizures in REM sleep. Compared to stage N3 sleep, there were 50.78 times less focal seizures, 2.22 times less focal interictal discharges, and 5.86 times less generalized seizures in REM sleep. Compared to wakefulness, there were 8.38 times less focal seizures and 16.4 times less generalized seizures in REM sleep. We also found that across 3 studies of generalized epilepsy where data were provided, no patients exhibited a highest rate of generalized discharges in REM sleep. Rather, highest rates of generalized discharges were found in stage N3 sleep for 61.1% of patients, wakefulness in 16.4%, stage N1 sleep in 16.1%, and stage N2 sleep in 6.4%.Conclusions: In our standardized review, we found that REM sleep is the most protective stage of sleep against focal seizures, focal interictal discharges, and generalized seizures. This antiepileptic effect also holds true when comparing REM sleep to wakefulness. We believe this finding sets the stage for further research into the basic mechanisms of sleep and epilepsy, and offers a promising future therapeutic avenue against epilepsy.