||In 1975, two Canadian physicians, and researchers, Harvey Moldofsky MD, and Hugh Smythe MD, were asked by colleagues at the University of Toronto to interview patients complaining of chronic muscle pain, for which no physiological cause could be found. Following the interviews these Canadian pioneer researchers, suspected sleep abnormality and further studied the patients using EEG. The device measured the patient's brain waves during sleep, and it was found that the patients had a deficiency in the stage of sleep, known as stage 4.
The researchers continued studying sleep disorder as a factor in FM. One of their studies involved awakening healthy people and disrupting their sleep pattern as they entered stage 4 of sleep. It was found that the healthy subjects developed FM symptoms when their sleep was disturbed, but the symptoms subsided when they slept, undisturbed.