Sleep disorders and circadian rhythm in epilepsy revisited: a prospective controlled study

Sleep disturbance is reported to be frequent in epilepsy. The role of comorbidity, which is frequently accompanied by sleep disturbance, has not been investigated. The present study assessed sleep disorders and circadian rhythm in patients with epilepsy, in whom relevant comorbidity was carefully excluded.

Two hundred patients with epilepsy (100 generalized, 100 partial), without relevant psychiatric, neurological or internal comorbidity, were compared with 100 matched controls. The questionnaire contained specifically tailored questions to address the association between epilepsy and sleep disturbance, and validated questionnaires aimed at sleep quality, excessive daytime sleepiness (EDS), circadian rhythm, sleep disorders, and quality of life.

Forty-one percent of the participants reported on the acute effects of present or past seizures on sleep-wake rhythm, whereas chronic effects were not evident. Participants and controls did not differ in the rates of chronic sleep disturbance, EDS, and presence of sleep disorders (all p-values non-significant or n.s.). Apart from earlier sleep times on workdays (p = 0.001) in those with epilepsy, circadian variables were similarly distributed. Epilepsy was well controlled, with 75.9% being seizure free for ≥ 1 year. Longer durations of epilepsy showed a negative correlation with sleep quality (rho = -0.256, p < 0.001). Participants with generalized and partial epilepsies did not differ in rates of sleep disturbance, EDS, sleep disorders, and variables of circadian rhythm (all p-values n.s.).

The present study demonstrated that chronic sleep disturbance is not increased in patients with well-controlled epilepsy without relevant comorbidity. This supports comorbidity and insufficient seizure control as major contributors of sleep disturbance in epilepsy.