Epilepsy and sleep have a close association and a two way interaction. Recognising this allows for a greater awareness of the importance of good quality sleep in epilepsy patients with potential benefits on seizure control and quality of life. This article reviews this complicated but fascinating area addressing diagnostic issues, the effects of epilepsy and its treatments on sleep, the effects of sleep disorders on epilepsy concluding with some practical advice on assessment.
Sleep and epilepsy are intimate bedfellows, having an impact on each other and adversely affecting quality of life and daytime performance.1 Sleep has an important role in memory consolidation.2 Sleep deprivation impairs this process3 and epilepsy can upset this delicate balance.4 Sleep disorders are up to three times as common in epilepsy5 and can be a major contributor to refractory seizures,6 poorer quality of life7 and possibly SUDEP.8 Recognition of the comorbid sleep disorder and successful treatment can lead to significant improvements in seizure control.9 Many patients with epilepsy have seizures in sleep, some exclusively so. Often diagnosis is difficult due to incomplete histories from sleep partners. Even when telemetry facilities are available, data can be difficult to interpret and EEG is not always diagnostic.10 To add to this complexity, epilepsy treatments often have impact on sleep. Understanding this complex relationship can lead to better treatment outcomes for patients. This review will begin with diagnostic issues, moving on to the effects of epilepsy and its treatments on sleep, the effects of sleep disorders on epilepsy and concludes with practical advice on assessment.
Epilepsy Syndromes Closely Associated with Sleep
There are a small number of epilepsy syndromes which are predominantly or exclusively associated with sleep (Table 1). Seizures arising from sleep are almost always of focal onset. These include the childhood onset syndromes of benign childhood epilepsy with centrotemporal spikes (BCECTS, Rolandic epilepsy), benign childhood epilepsy with occipital paroxsysms (Panayiotopoulos syndrome) and the frontal lobe epilepsy syndromes (including autosomal dominant nocturnal frontal lobe epilepsy ADNFLE). Idiopathic generalised epilepsy syndromes (IGE) such as juvenile myoclonic epilepsy (JME) and generalised tonic clonic seizures on waking arise shortly before or after sleep onset but not from a sleep state.