Disturbed sleep in cluster headache is not the result of transient processes associated with the cluster period.

BACKGROUND AND PURPOSE: Cluster headache (CH) is characterized by severe, unilateral attacks of pain and a high nocturnal attack burden. It remains unknown whether perturbations of sleep are solely present during the CH bout. Therefore, we aimed to investigate differences in sleep between the bout and remission period in patients with episodic CH and, secondly, to compare patients in the two phases with controls. METHODS: Patients with episodic CH (aged 18-65 years), diagnosed according to the International Classification of Headache Disorders 2nd edition, were admitted for polysomnography at the Danish Center for Sleep Medicine in bout and in remission. The macrostructure of sleep, including arousals, breathing parameters, limb movements and periodic limb movements, was compared with 25 age-, sex- and body mass index-matched healthy controls. RESULTS: There were no differences in any of the sleep parameters for patients in bout (n = 32) compared with patients in remission (n = 23). Attacks were unrelated to sleep stages, presence of apnea episodes, periodic limb movements, limb movements and arousals. In bout, patients had longer sleep latency (18.8 vs. 11.7 min, P < 0.05) and rapid eye movement sleep latency (1.7 vs. 1.2 h, P < 0.05) than controls and sleep efficiency was lower (82.5% vs. 86.5%, P < 0.05). Patients in remission only had a longer sleep latency compared with controls (17.5 vs. 11.7 min, P < 0.01). CONCLUSIONS: The results support the presence of a continuing or slowly recovering disturbance of sleep outside the bout rather than a disturbance occurring secondary to attacks. Further, we confirm that there is no relation between CH attacks and specific sleep stages or between CH and breathing parameters.

Sleep in cluster headache - beyond a temporal rapid eye movement relationship?

BACKGROUND AND PURPOSE: Cluster headache (CH) is a primary headache disorder characterized by severe attacks of unilateral pain following a chronobiological pattern. There is a close connection with sleep as most attacks occur during sleep. Hypothalamic involvement and a particular association with rapid eye movement (REM) sleep have been suggested. Sleep in a large, well-characterized population of CH patients was investigated. METHODS: Polysomnography (PSG) was performed on two nights in 40 CH patients during active bout and one night in 25 age, sex and body mass index matched controls in hospital. Macrostructure and other features of sleep were analyzed and related to phenotype. Clinical headache characterization was obtained by semi-structured interview. RESULTS: Ninety-nine nights of PSG were analyzed. Findings included a reduced percentage of REM sleep (17.3% vs. 23.0%, P = 0.0037), longer REM latency (2.0 vs. 1.2 h, P = 0.0012) and fewer arousals (7.34 vs. 14.1, P = 0.003) in CH patients. There was no difference in prevalence of sleep apnea between patients (38%) and matched controls (32%, P = 0.64) although the apnea index in patients was numerically higher (mean apnea-hypopnea index 10.75 vs. 4.93). No temporal association between nocturnal attacks (n = 45) and particular sleep stages was observed. CONCLUSIONS: To date, this is the largest study of sleep in CH. It is demonstrated that REM sleep is affected which is in line with our current understanding of CH and hypothalamic involvement in the regulation of this sleep stage. Further, fewer arousals were found in CH patients but no association between apnea events or specific sleep stages. The findings support a central role of the hypothalamus and arousal systems in CH.