This definition appears very rarely
Samples in periodicals archive:
A joint venture of the American Academy of Sleep Medicine and the Sleep Research Society.
Journal of Clinical Sleep Medicine : JCSM : Official Publication of the American Academy of Sleep Medicine Vols. 3 to 11; 2007 to 2015; Vol. 11
Sleep health information from the American Academy of Sleep Medicine. Symptoms and treatments for insomnia, sleep apnea and sleep disorders. Find a sleep center for...