Page 180 - ILAE_Lectures_2015

Chapter 18

Epilepsy and sleep

SOFIA H. ERIKSSON

Department of Clinical and Experimental Epilepsy, National Hospital for Neurology and
Neurosurgery, Queen Square, London
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The relationship between epilepsy and sleep is complex as seizures may be exacerbated by
sleep deprivation and some seizures mainly occur during sleep. Further, there is a possibility
of nocturnal seizures being misdiagnosed as parasomnia and vice versa. Finally, sleep
disorders may aggravate epilepsy and epilepsy may aggravate certain sleep disorders.
Normal sleep physiology and relationship to seizures
Sleep consists of active brain states during which many biological processes occur, such as
synaptic plasticity and memory consolidation1. Using electroencepahalography (EEG) sleep
can be broadly divided into rapid eye movement (REM) sleep and non-REM (NREM) sleep.
NREM can be subdivided into light (stages I/II) and deep (stage III, previously split into
stages III/IV) sleep. These sleep states cycle over 90 minutes throughout the night. Deep sleep
mainly occurs during the first part of the night, and towards morning there is more REM sleep
(Figure 1). The transition between wakefulness and sleep and between different sleep stages
is often gradual and the mechanisms controlling these transitions are poorly understood.

Figure 1. Normal hypnogram. Note that there is more deep sleep in the first parts of the night
and more REM sleep towards morning.