Non 24 hour sleep wake disorder
Other Names for this Disease
- Circadian rhythm sleep disorder, free-running type
- Hypernychthemeral syndrome
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 Non 24 hour sleep wake disorder can also affect sighted people. The cause of the disorder in these cases is incompletely understood, but studies suggest melatonin levels play a role.Non 24 hour sleep wake disorder refers to a steady pattern of one- to two-hour delays in sleep onset and wake times in people with normal living conditions. This occurs because the period of the person's sleep-wake cycle is longer than 24 hours. The condition most commonly affects people who are blind, due to an impaired sense of light-dark cycles.
Last updated: 6/3/2014
- Judd BG, Sateia MJ. Classification of sleep disorders. In: Basow M. UpToDate. Waltham, MA: UpToDate; 2014; Accessed 6/2/2014.
- Hayakawa T, Uchiyama M, Kamei Y, Shibui K, Tagaya H, Asada T, Okawa M, Urata J, Takahashi K. Clinical analyses of sighted patients with non-24-hour sleep-wake syndrome: a study of 57 consecutively diagnosed cases. Sleep. August 1, 2005; 28(8):945-52. http://www.ncbi.nlm.nih.gov/pubmed/16218077. Accessed 6/2/2014.
- Uchiyama M et al. Larger phase angle between sleep propensity and melatonin rhythms in sighted humans with non-24-hour sleep-wake syndrome. Sleep. 2002 Feb 1; 25(1):83-8. http://www.ncbi.nlm.nih.gov/pubmed/11833864. Accessed 6/3/2014.
On this page
- The Monarch Initiative brings together data about this condition from humans and other species to help physicians and biomedical researchers. Monarch’s tools are designed to make it easier to compare the signs and symptoms (phenotypes) of different diseases and discover common features. This initiative is a collaboration between several academic institutions across the world and is funded by the National Institutes of Health. Visit the website to explore the biology of this condition.
- Orphanet is a European reference portal for information on rare diseases and orphan drugs. Access to this database is free of charge.
- PubMed is a searchable database of medical literature and lists journal articles that discuss Non 24 hour sleep wake disorder. Click on the link to view a sample search on this topic.