Sleep and stroke.

Although the incidence of strokes is not maximal during sleeping hours, several lines of evidence make it probable that sleep in combination with breathing disorders like snoring and obstructive apneas are risk factors for ischemic strokes: the natural history of snoring and obstructive sleep apnea shows a higher incidence of strokes than in undisturbed sleep, the prevalence of snoring and sleep apneas in stroke patients is by far higher than in non-stroke patients; odds-ratios of stroke are higher in snorers and apneic patients than in normals, although the correction for confounders seems never perfect. The analysis of potential pathomechanisms linking sleep disordered breathing to strokes is another approach to the main topic: snoring and sleep apnea induce hypertension and arrhythmia, the carotid intima-media-thickness is increased, carotid atheromas are more common among apneics than among normals, the flow in the A. cerebri media is as well altered as the reaction to angiotensine II, noradrensine, isoproterenol and bradykinin. Homocysteine is increased, plasminogen activator inhibitor type 1 is inhibited and platelets are activated leading to an increased risk of thrombosis. There are no studies showing the effectiveness of treatment with nasal continuous positive airway pressure (nCPAP) on the rehabilitation of apneic stroke patients, but the outcome of non-apneic stroke patients is better than that of apneic stroke patients.