Display Settings:


Send to:

Choose Destination
See comment in PubMed Commons below
Sleep Med. 2009 May;10(5):549-55. doi: 10.1016/j.sleep.2008.03.020. Epub 2008 Aug 23.

Clinical efficacy of dim light melatonin onset testing in diagnosing delayed sleep phase syndrome.

Author information

  • 1Sleep Research Laboratory, University Health Network, Toronto, Ont., Canada.



Delayed Sleep Phase Syndrome (DSPS) arises from biological clock desynchrony and accounts for 10% of chronic insomnia patients. Currently DSPS is diagnosed based on sleep/wake cycle disruptions rather than examining the underlying biological clock alterations. The objective of the study was to determine the sensitivity and specificity of the Dim Light Melatonin Onset (DLMO) Test in diagnosing DSPS in a clinical setting.


Fifty-six patients (mean age 28 years) symptomatic of DSPS participated in the study. Following an initial assessment of DSPS using sleep diaries, participants underwent two consecutive nights of polysomnography (PSG), with an imposed sleep period on the second night to demonstrate the delay in the timing of habitual sleep period and to thereby confirm DSPS. Circadian phase delays were also measured using melatonin secretion profiles, and the efficacy of diagnosing DSPS using DLMO was compared to using sleep diaries and PSG. Melatonin secretion was assayed for each individual by ELISA using saliva samples.


Main outcome measures included the time of melatonin secretion onset, clinical sensitivity and specificity of the DLMO test. The time of melatonin secretion onset was significantly delayed in DSPS patients. Clinical sensitivity and specificity of the DLMO test in diagnosing DSPS were 90.3% and 84.0%, respectively.


The DLMO test is an accurate tool for differentiating between sleep disorder patients with or without underlying circadian rhythm disruption. It is effective for phase typing DSPS patients in a clinical setting.

[PubMed - indexed for MEDLINE]

LinkOut - more resources

Full Text Sources

Other Literature Sources

Molecular Biology Databases

PubMed Commons home

PubMed Commons

How to join PubMed Commons

    Supplemental Content

    Full text links

    Icon for Elsevier Science
    Loading ...
    Write to the Help Desk