Shorter duration of slow wave sleep is related to symptoms of depression in patients with epilepsy

TL;DR

This study investigates how depressive symptoms influence slow wave sleep duration in epilepsy patients, revealing that depression is associated with shorter slow wave sleep regardless of epilepsy type, highlighting its potential impact on seizure risk.

Contribution

It provides new evidence linking depressive symptoms to reduced slow wave sleep duration in epilepsy patients, independent of medication and demographic factors.

Findings

Depressive symptoms correlate with shorter slow wave sleep duration.

Psychoactive medication is associated with longer slow wave sleep.

Frontal sigma power differs between patients with and without depression.

Abstract

Slow wave sleep duration and spectral abnormalities are related to both epilepsy and depression, but it is unclear how depressive symptoms in patients with epilepsy are affected by slow wave sleep duration and clinical factors, and how the spectral characteristics of slow wave sleep reflect a potential interaction of epilepsy and depression. Long-term video-EEG monitoring was conducted in 51 patients with focal epilepsy, 13 patients with generalized epilepsy, and 9 patients without epilepsy. Slow wave sleep segments were manually marked in the EEG and duration as well as EEG power spectra were extracted. Depressive symptoms were documented with the Beck Depression Inventory (BDI). At least mild depressive symptoms (BDI>9) were found among 23 patients with focal epilepsy, 5 patients with generalised epilepsy, and 6 patients who had no epilepsy diagnosis. Slow wave sleep duration was shorter for patients with at least mild depressive symptoms (p=.004), independently from epilepsy diagnosis, antiseizure medication, age, and sex. Psychoactive medication was associated with longer slow wave sleep duration (p=.008). Frontal sigma band power (13-15 Hz) during slow wave sleep was higher for patients without epilepsy and without depressive symptoms as compared to patients without depressive symptoms but with focal epilepsy (p=.005). Depressive symptoms affect slow wave sleep duration of patients with epilepsy similarly as in patients without epilepsy. Since reduced slow wave sleep can increase the likelihood of seizure occurrence, these results stress the importance of adequate treatment for patients with epilepsy who experience depressive symptoms.