Sleep Domain Predictors of Headache-Related Disability in Episodic Migraine and Cluster Headache: A Prospective...

Background: Sleep disturbance is a well-recognized contributor to headache burden, yet the specific sleep domains associated with disability may differ between episodic migraine (EM) and episodic cluster headache (ECH). Methods: In this prospective observational study, 20 EM patients, 21 ECH patients, and 18 age-, sex-, and BMI-matched healthy controls (HCs) were evaluated during interictal periods. None of the patients were receiving prophylactic headache treatment. Sleep was assessed using the Pittsburgh Sleep Quality Index (PSQI), Insomnia Severity Index (ISI), Epworth Sleepiness Scale (ESS), and Sleep Hygiene Index (SHI). Psychological status was measured with the Hospital Anxiety and Depression Scale (HADS). Headache-related disability was assessed using the Headache Impact Test-6 (HIT-6) as a continuous outcome. Separate multivariable linear regression models were constructed for each headache group. Results: Both headache groups showed significantly impaired sleep and higher anxiety and depression scores compared with controls (all p < 0.001). HIT-6 scores did not differ between EM and ECH (p = 0.770 after Bonferroni correction). In multivariable regression, excessive daytime sleepiness (ESS) independently predicted disability in EM (B = 1.633, p = 0.033; R² = 0.571). In ECH, global sleep quality (PSQI; B = 0.701, p = 0.004) and sleep hygiene (SHI; B = 0.557, p = 0.033) were independently associated with HIT-6 (R² = 0.562). No significant multicollinearity was observed (all VIF < 2.5). Conclusions: Sleep disturbance is prevalent in both EM and ECH; however, the sleep domains associated with disability differ between phenotypes. Daytime sleepiness is more relevant in EM, whereas global sleep quality and sleep hygiene are more strongly associated with disability in ECH. These findings support a phenotype-specific approach to sleep assessment in headache management.