Trastornos circadianos del sueño

Abstract

The circadian system is synchronized to the light-dark cycle generated by the rotation of the earth, ensuring that wake¬fulness is during the day and sleep occurs at night. However, the sleep-wake rhythm may be out of sync with the light-dark cycle or endogenously out of sync, resulting in insomnia, fatigue, and poor performance in activities of daily living. Sleep disorders are classified by the American Sleep Disorders Association, as intrinsic dyssomnias, extrinsic dyssomnias, parasomnias, or medical/psychiatric sleep disorders. Circa¬dian sleep disorders have been categorized separately to recognize that in most cases the etiology of circadian dis¬turbances is a mix of internal and environmental factors or a temporary mismatch between the two. Symptoms are usually insomnia or hypersomnia, common symptoms in patients with circadian sleep disorders although other causes can be attributed and must be excluded before a diagnosis of a circadian sleep disorder is made. In the patient without other sleep pathology, a daily record of activities, meals, exercise, naps, and bedtime is an essential tool in assessing circadian sleep disorders. These records should be kept for 2 weeks or more, as a disturbance due to job changes or travel across time zones can have effects on sleep and daytime alertness weeks after the event. Keywords: Sleep; biological rhythms; jet-lag; insomnia; light-dark cycle.