Why Are Seizures Rare in Rapid Eye Movement Sleep? Review of the Frequency of Seizures in Different Sleep Stages

TLDR

Seizures have been reported to preferentially occur in specific sleep stages, and REM sleep is characterized by low‑voltage fast EEG activity, rapid eye movements, and muscle atonia, and has also been used to localize epileptogenic foci. The study hypothesizes that REM sleep’s desynchronized EEG pattern, reflecting unique connectivity differences, underlies its influence on seizure occurrence. The authors reviewed 42 conventional and intracranial studies encompassing 1,458 patients. Across 1,458 patients, REM sleep was associated with a strikingly low seizure proportion (~1%) and was the most protective stage, reducing focal seizures by 7.83‑fold, generalized seizures by 3.25‑fold, and focal interictal discharges by 1.11‑fold compared with wakefulness.

Abstract

Since the formal characterization of sleep stages, there have been reports that seizures may preferentially occur in certain phases of sleep. Through ascending cholinergic connections from the brainstem, rapid eye movement (REM) sleep is physiologically characterized by low voltage fast activity on the electroencephalogram, REMs, and muscle atonia. Multiple independent studies confirm that, in REM sleep, there is a strikingly low proportion of seizures (~1% or less). We review a total of 42 distinct conventional and intracranial studies in the literature which comprised a net of 1458 patients. Indexed to duration, we found that REM sleep was the most protective stage of sleep against focal seizures, generalized seizures, focal interictal discharges, and two particular epilepsy syndromes. REM sleep had an additional protective effect compared to wakefulness with an average 7.83 times fewer focal seizures, 3.25 times fewer generalized seizures, and 1.11 times fewer focal interictal discharges. In further studies REM sleep has also demonstrated utility in localizing epileptogenic foci with potential translation into postsurgical seizure freedom. Based on emerging connectivity data in sleep, we hypothesize that the influence of REM sleep on seizures is due to a desynchronized EEG pattern which reflects important connectivity differences unique to this sleep stage.