Sleep disturbances are an important health problem; about 20-33% of the population suffer from hyposomnias (lack of sleep). Hyposomnias often accompany neurological disorders (head traumas, chronic cephalea, pain, cerebrovascular and neuromuscular disorders, M. Parkinson, and dementia). Slow wave sleep decreases, arousals increase, and sleep is fragmented; these types of hyposomnias are treated by treatment of the basic neurological disease. Some sleep disturbances (e.g. sleep apneas) are a risk factor for cerebrovascular disorders.