Fig. 2From: Patients with cluster headache show signs of insomnia and sleep related stress: results from an actigraphy and self-assessed sleep studyCorrelation between sleep time and age in cluster headache patients and controls. Left panel: controls (dark grey dots) p-value from linear regression analysis=0.02, Right panel: Cluster Headache (CH) patients (light grey dots) p-value from linear regression analysis=0.6Back to article page