In chronotherapy, an attempt is made to move bedtime and rising time later and later each day, around the clock, until a person is sleeping on a normal schedule. This treatment can be used by people with delayed sleep phase disorder (DSPD), who generally cannot reset their circadian rhythm by moving their bedtime and rising time earlier. DSPD is a circadian rhythm sleep disorder, characterised by a mismatch between a person's internal biological clock and societal norms. Chronotherapy uses the human phase response to light or melatonin. The American Academy of Sleep Medicine has recommended chronotherapy for the treatment of circadian rhythm and sleep disorders.
Non-24-hour sleep–wake disorder is one of several chronic circadian rhythm sleep disorders (CRSDs). It is defined as a "chronic steady pattern comprising [...] daily delays in sleep onset and wake times in an individual living in a society". Symptoms result when the non-entrained (free-running) endogenous circadian rhythm drifts out of alignment with the light–dark cycle in nature. Although this sleep disorder is more common in blind people, affecting up to 70% of the totally blind, it can also affect sighted people. Non-24 may also be comorbid with bipolar disorder, depression, and traumatic brain injury. The American Academy of Sleep Medicine (AASM) has provided CRSD guidelines since 2007 with the latest update released in 2015.
Actigraphy is a non-invasive method of monitoring human rest/activity cycles. A small actigraph unit, also called an actimetry sensor, is worn for a week or more to measure gross motor activity. The unit is usually in a wristwatch-like package worn on the wrist. The movements the actigraph unit undergoes are continually recorded and some units also measure light exposure. The data can be later read to a computer and analysed offline; in some brands of sensors the data are transmitted and analysed in real time.
The American Academy of Sleep Medicine (AASM) is a United States professional society for the medical subspecialty of sleep medicine which includes disorders of circadian rhythms. It was established in 1975.
Michel Valentin Marcel Jouvet was a French neuroscientist and medical researcher.
Circadian rhythm sleep disorders (CRSD), also known as circadian rhythm sleep-wake disorders (CRSWD), are a family of sleep disorders which affect the timing of sleep. CRSDs arise from a persistent pattern of sleep/wake disturbances that can be caused either by dysfunction in one's biological clock system, or by misalignment between one's endogenous oscillator and externally imposed cues. As a result of this mismatch, those affected by circadian rhythm sleep disorders have a tendency to fall asleep at unconventional time points in the day. These occurrences often lead to recurring instances of disturbed rest, where individuals affected by the disorder are unable to go to sleep and awaken at "normal" times for work, school, and other social obligations. Delayed sleep phase disorder, advanced sleep phase disorder, non-24-hour sleep–wake disorder and irregular sleep–wake rhythm disorder represents the four main types of CRSD.
The International Classification of Sleep Disorders (ICSD) is "a primary diagnostic, epidemiological and coding resource for clinicians and researchers in the field of sleep and sleep medicine". The ICSD was produced by the American Academy of Sleep Medicine (AASM) in association with the European Sleep Research Society, the Japanese Society of Sleep Research, and the Latin American Sleep Society. The classification was developed as a revision and update of the Diagnostic Classification of Sleep and Arousal Disorders (DCSAD) that was produced by both the Association of Sleep Disorders Centers (ASDC) and the Association for the Psychophysiological Study of Sleep and was published in the journal Sleep in 1979. A second edition, called ICSD-2, was published by the AASM in 2005. The third edition, ICSD-3, was released by the AASM in 2014. A text revision of the third edition (ICSD-3-TR) was published in 2023 by the AASM.
Sleep medicine is a medical specialty or subspecialty devoted to the diagnosis and therapy of sleep disturbances and disorders. From the middle of the 20th century, research has provided increasing knowledge of, and answered many questions about, sleep–wake functioning. The rapidly evolving field has become a recognized medical subspecialty in some countries. Dental sleep medicine also qualifies for board certification in some countries. Properly organized, minimum 12-month, postgraduate training programs are still being defined in the United States. In some countries, the sleep researchers and the physicians who treat patients may be the same people.
Russell Grant Foster, CBE, FRS FMedSci is a British professor of circadian neuroscience, the Director of the Nuffield Laboratory of Ophthalmology and the Head of the Sleep and Circadian Neuroscience Institute (SCNi). He is also a Nicholas Kurti Senior Fellow at Brasenose College at the University of Oxford. Foster and his group are credited with key contributions to the discovery of the non-rod, non-cone, photosensitive retinal ganglion cells (pRGCs) in the mammalian retina which provide input to the circadian rhythm system. He has written and co-authored over a hundred scientific publications.
Robert Leroy Sack is an American physician and researcher specializing in sleep medicine. He is certified by the American Board of Psychiatry and Neurology and the American Board of Sleep Disorders Medicine. On the faculty of the Oregon Health & Science University since 1977, he is the medical director of its Clinical Sleep Disorders Medicine Program which he developed parallel with his research on circadian rhythms.
Charles Andrew Czeisler is a Hungarian-American physician and sleep and circadian researcher. He is a leading researcher and author in the fields of the effects of light on human physiology, circadian rhythms and sleep medicine.
Fred W. Turek is the Director of the Center for Sleep & Circadian Biology and the Charles E. & Emma H. Morrison Professor of Biology in the Department of Neurobiology, both at Northwestern University. Turek received his Ph.D from Stanford University. He was awarded a Guggenheim Fellowship in 1991.
The British Sleep Society (BSS) was established in 1988 to support clinicians, researchers, nurses, technologists, scientists and students with an interest in sleep and sleep disorders. It acts as an umbrella organisation, with a number of roles and activities. The Society advises health services policy through submitting evidence for consideration by the National Institute for Health and Care Excellence (NICE). It organises an influential scientific meeting each year dedicated to sleep disorders and sleep research and jointly hosts an annual international education course for sleep technologists and clinicians. The Society has charitable status, and operates throughout England, Wales, Northern Ireland and Scotland. It serves the media, fund raisers, commerce and concerned members of the public with support and advice.
Classification of sleep disorders comprises systems for classifying medical disorders associated with sleep. Systems have changed, increasingly using technological discoveries to advance the understanding of sleep and recognition of sleep disorders.
The National Sleep Foundation (NSF) is an American non-profit, charitable organization. Founded in 1990, its stated goal is to provide expert information on health-related issues concerning sleep. It is largely funded by pharmaceutical and medical device companies.
The Society for Research on Biological Rhythms (SRBR) is an international chronobiological research society with three key goals:
- to promote the advancement and dissemination of basic and applied research in all aspects of biological rhythms.
- to enhance the education and training of students and researchers in the field.
- to foster interdisciplinary communication and an international exchange of ideas.
Phyllis C. Zee is the Benjamin and Virginia T. Boshes Professor in Neurology, the director of the Center for Circadian and Sleep Medicine (CCSM) and the chief of the Division of Sleep Medicine (neurology) at the Feinberg School of Medicine, Northwestern University, Chicago. She is also the medical director of Sleep Disorders Center at Northwestern Memorial Hospital.
Dr. Debra J. Skene is a chronobiologist with specific interest in the mammalian circadian rhythm and the consequences of disturbing the circadian system. She is also interested in finding their potential treatments for people who suffer from circadian misalignment. Skene and her team of researchers tackle these questions using animal models, clinical trials, and most recently, liquid chromatography-mass spectrometry. Most notably, Skene is credited for her evidence of a novel photopigment in humans, later discovered to be melanopsin. She was also involved in discovering links between human PER3 genotype and an extremely shifted sleep schedules categorized as extreme diurnal preference. Skene received her Bachelor of Pharmacy, Master of Science, and Ph.D. in South Africa.
Charmane Eastman is an American academic research scientist whose career has focused on studying circadian rhythms and their relationships to sleep, jet lag, and shift work. She has also studied winter depression, more properly known as seasonal affective disorder (SAD). Of special focus are the effects of bright light and melatonin on circadian rhythms.
Elizabeth Klerman is a professor of neurology at Harvard Medical School. Her research focuses on applying circadian and sleep research principles to human physiology and pathophysiology. She also uses mathematical analysis and modeling to study human circadian, sleep, and objective neurobehavioral performance and subjective (self-reported) mood and alertness rhythms.
