Clinical Trial: Light Sensitization Study
Study Status: Active, not recruiting
Recruit Status: Active, not recruiting
Study Type: Interventional
Official Title: Sensitization of Human Circadian Responses to Light
Brief Summary: Circadian rhythm disorders are a class of sleep disorders characterized by misalignment between the timing of sleep and the timing of rhythms driven by the biological clock. Light therapy can effectively treat these disorders, but the intensity and duration of light exposure required to do so has limited its practical use. In this study the investigators will test whether pre-exposure to dim light may enhance the response of the circadian system to light therapy. If so, this could result in shorter treatments that would have greater practical applications.
Detailed Summary:
Sleep disorders affect 35-40% of adults, resulting in diminished quality of life, and increased morbidity, mortality, and risk of automobile and occupational accidents. Circadian rhythm sleep disorders form a distinct class of sleep disorders characterized by misalignment between the timing of sleep and the circadian pacemaker. While light therapy can be an effective treatment of circadian rhythm sleep disorders, there are numerous practical limitations.
Light is the most powerful signal from the environment that influences and regulates daily biological rhythms. It is well-established that the irradiance, duration, and timing of light exposure all affect the response of the circadian system. While it was once thought that these responses were mediated through the visual system, it is now known that there is a network of intrinsically photosensitive retinal ganglion cells (ipRGCs) that mediate circadian responses to light. Other new studies have demonstrated that recent light exposure history affects the circadian response to light in humans.
These recent findings have important implications for the use of light to treat circadian rhythm disorders, including delayed and advanced sleep phase disorders, shift work sleep disorder, and jet lag, and they may also have relevance for the use of light to treat seasonal affective disorder. Up to now, little attention has been paid to the duration or intensity of light exposure prior to such light treatments. The investigators now have evidence that the human circadian system can become desensitized to light during long exposures and evidence that it can be sensitized to light by prior exposure to dim light. These recent findings suggest that light treatment protocols that sensitize the circadian system prior to the light treatment will be more effective than those currently in use.
Sponsor: Brigham and Women's Hospital
Current Primary Outcome: circadian phase timing [ Time Frame: During inpatient study, on days 6-7 and 11-12 ]
Original Primary Outcome: circadian phase timing [ Time Frame: on inpatient study days 6-7 and 11-12 ]
Current Secondary Outcome: melatonin suppression [ Time Frame: During inpatient study, on days 6-7 and 11-12 ]
Original Secondary Outcome: melatonin suppression [ Time Frame: on inpatient study days 6-7 and 11-12 ]
Information By: Brigham and Women's Hospital
Dates:
Date Received: March 30, 2011
Date Started: October 2010
Date Completion: December 2017
Last Updated: January 13, 2017
Last Verified: January 2017
