Embodiments of the invention relate to the use of a melatonin agonist in the treatment of free running circadian rhythms in patients, including light perception impaired patients, e.g., blind patients, and to methods of measuring circadian rhythm.

Embodiments of the invention relate to the use of a melatonin agonist in the treatment of free running circadian rhythms in patients, including light perception impaired patients, e.g., blind patients, and to methods of measuring circadian rhythm.

The present subject matter relates to a method of diagnosing and treating sleep apnea (SA) in a subject. The method may include determining whether the subject needs a Polysomnography by obtaining a biological sample from the subject to determine if the subject has a metabolite selected from the group consisting of PC-O-(38:3), SM (43:1), LPC (24:1), PC (46:1), and TG (44:1). Expression of one of the metabolites may be associated with the presence of SA in a subject. If the subject has a metabolite associated with the presence of SA, then the method includes conducting a Polysomnography on the subject to further determine if the subject has SA. If the subject is further determined to have SA, the method may then include treating the subject with a treatment of SA selected from the group consisting of ENT multilevel surgery, continuous positive airway pressure therapy, and bariatric surgery.