Sleep-disordered breathing and stroke: chicken or egg?

The bidirectional interaction between sleep-disordered breathing (SDB) and stroke has been the subject of many studies. On the one hand, different forms of SDB, and especially obstructive sleep apnea, increase the risk of stroke either directly or indirectly by influencing other known cardiovascular risk factors such as arterial hypertension and arrhythmias. On the other hand, stroke itself can cause either de novo appearance of SDB, aggravate a pre-existing SDB, or trigger a transition from one type of pathological SDB pattern into another. In this review, we discuss some aspects of this "chicken or egg" relationship.