Stroke during sleep: Epidemiological and clinical features

Stroke during sleep is an unexplored area of vascular neurology and its pat hogenesis; clinical significance and prevention still remain uncertain. The aim of our study was to determine the epidemiological and clinical pattern s of ischemic stroke occurring during sleep. Consecutive patients (n = 1822 ) with acute ischemic stroke recorded in the Tel Aviv Stroke Register were studied. Stroke during sleep was determined whenever focal neurological def icit was verified to have occurred while the patient had been asleep. The c omparisons between patients with stroke during sleep and while awake were p erformed using the t test with Bonferroni correction and the chi(2) test fo r age, sex, vascular risk factors (i.e. ischemic heart disease, myocardial infarction, atrial fibrillation, arterial hypertension, hyperlipidemia, dia betes mellitus, peripheral vascular disease, smoking), vascular distributio n (carotid versus vertebrobasilar) and severity of stroke (mild, moderate o r severe). Data regarding the onset of stroke (during sleep or while awake) were available for 1,671 patients. A minority of strokes occurred during s leep (n = 311, 18.6%), and stroke during sleep was severer (chi(2) = 11.9, p < 0.002). No significant differences were found in terms of age, sex and vascular distribution between the two groups. None of the vascular risk fac tors was found to be more frequent in stroke during sleep. Strokes occurrin g during sleep were found to be severer than those with onset while awake. However, no specific clinical patterns of risk factor profiles could be ide ntified in these patients. Hemodynamic factors may play an important role i n the occurrence of stroke during sleep, and this issue should be further i nvestigated.