Sleep medicine

Sleep medicine is a medical specialty or subspecialty devoted to the diagnosis and therapy of sleep disturbances and disorders.^[1] From the middle of the 20th century, research in the field of somnology has provided increasing knowledge of, and answered many questions about, sleep–wake functioning.^[2] The rapidly evolving field has become a recognized medical subspecialty, with somnologists practicing in various countries.^[3][4] 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.^[5][6] The sleep physicians who treat patients (known as somnologists),^[4] may dually serve as sleep researchers in certain countries.

The first sleep clinics in the United States were established in the 1970s by interested physicians and technicians; the study, diagnosis and treatment of obstructive sleep apnea were their first tasks. As late as 1999, virtually any American physician, with no specific training in sleep medicine, could open a sleep laboratory.^[7]

Disorders and disturbances of sleep are widespread and can have significant consequences for affected individuals as well as economic and other consequences for society.^{[8][9][10][11]} The US National Transportation Safety Board has, according to Charles Czeisler, member of the Institute of Medicine and Director of the Harvard University Medical School Division of Sleep Medicine at Brigham and Women's Hospital, discovered that the leading cause (31%) of fatal-to-the-driver heavy truck crashes is fatigue related (though rarely associated directly with sleep disorders, such as sleep apnea), with drugs and alcohol as the number two cause (29%).^[12] Sleep deprivation has also been a significant factor in dramatic accidents, such as the Exxon Valdez oil spill, the nuclear incidents at Chernobyl and Three Mile Island and the explosion of the space shuttle Challenger.^[13]