[Unexplained confusion in the aged as a sequela of central sleep apnea syndrome--a case report].

Central sleep apnoea syndromes (cSAS) represent a heterogeneous group of sleep-related disorders of breathing during sleep. cSAS may develop in the course of neurological syndromes or congestive heart failure. Frequency increases with age. A case of a 89-year old man is reported who was sent to hospital because of a state of confusion. He fell asleep all day with periods of restlessness during night. Sleep-related apnoeas could already be observed during daytime. Cardiopulmonary daytime diagnostics did not reveal any abnormal findings. Polysomnographic measurements, however, showed an apnoea-hypopnoea index of 37.8 apnoeas/hypopnoeas per hour with predominantly central apnoeas. Pernasal application of 1 litre of oxygen per minute during sleep normalised breathing patterns, daytime sleepiness, and the nighttime states of confusion stopped. Consequently, sleep-related disorders of breathing have to be considered in the differential diagnostics of unclear states of confusion in old age. In these cases polysomnography is indicated even in geriatric patients.