Obstructive Sleep Apnea Syndrome (OSAS) is associated with stroke as a risk factor but little is known about the consequences of OSAS on the outcome and the survival after stroke. The aim of the investigators study is first to evaluate the outcome and the survival of patients with stroke depending of OSAS (presence and severity of OSAS) and second to compare the outcome and survival of patients with severe OSAS depending on the treatment of the syndrome with nocturnal continuous positive airway pressure. The investigators hypothesis is that OSAS is associated with worst survival and outcome and needs to be treated at the subacute phase of stroke.