Sleep in cluster headache revisited: Results from a controlled actigraphic study.

Cluster headache attacks exhibit a nocturnal predilection, but little is known of long-term sleep and circadian rhythm. The aim was to compare actigraphy measures, firstly in episodic cluster headache patients in bout and in remission and, secondly, to compare each disease phase with controls. Episodic cluster headache patients (ICHD III-beta), from the Danish Headache Center and healthy, age- and sex-matched controls participated. Sleep and activity were measured using actigraphy continuously for 2 weeks, along with sleep diaries and, for patients, also attack registration. Patients in bout (n = 17, 2.3 attacks/day) spent more time in bed (8.4 vs. 7.7 hours, p = 0.021) and slept more (7.2 vs. 6.6 hours, p = 0.036) than controls (n = 15). In remission (n = 11), there were no differences compared with controls. Neither were there differences between patients in the two disease phases. In five patients, attacks/awakenings occurred at the same hour several nights in a row. Actigraphy offers the possibility of a continuous and long study period in a natural (non-hospital) environment. The study indicates that sleep does not differ between the bout and remission phase of episodic cluster headache. The repeated attacks/awakenings substantiate that circadian or homeostatic mechanisms are involved in the pathophysiology. The protocol was made available at ClinicalTrials.gov (NCT02853487).