Subjective sleep disturbance in epilepsy patients at an outpatient clinic: A questionnaire-based study on prevalence

The clinically important interaction between epilepsy and sleep is complex. The aim of this paper is to review the frequency of sleep complaints and the comorbidity of sleep disorders in people with epilepsy attending an outpatient clinic.

Sleep complaints and presence of sleep disorders were assessed by means of a standard questionnaire form composed of 132 questions in 208 patients and 212 controls. The questionnaire includes Pittsburgh Sleep Quality Index, the Epworth Sleepiness Scale, the Beck Depression Scale, and the Berlin Questionnaire for sleep apnea.

We showed poorer sleep quality, a higher frequency of subjective sleep disturbances in epilepsy patients. The major complaints of patients related to poor sleep quality included the symptoms of insomnia, sleep apnea, and parasomnias. They have higher frequency of sleep onset and maintenance insomnia, REM behavioral disorders, and sleep apnea. Nocturnal seizures (47%) and epileptiform activities on EEG (47%) were more frequent in patients with insomnia (p=0.02, p=0.06). Furthermore, the patients with a high risk of sleep apnea frequently used more than one antiepileptic drugs (AED) (41%, p<0.01) and the duration of epilepsy was longer in these patients (p=0.02). Moreover insomnia (p=0.01) was significantly lower in patients having no seizures in the last 2 years and the risk of apnea (p=0.04) and bad quality of sleep (p=0.01) was higher in patients with seizures.

The results emphasize the extent of the comorbidity of sleep disorders and epilepsy in an outpatient clinic. They have higher frequency of sleep onset, maintenance insomnia, probable RBD, and sleep apnea than healthy controls do. The severity of epilepsy can increase the risk of some sleep disorders like insomnia and sleep apnea. Aggressive treatment of nocturnal seizures and EEG can be considered to prevent insomnia. On the other hand, chronicity can lead to sleep apnea and so PSG investigations can be routinely done in patients having video-EEG monitoring due to refractory epilepsy.