Light Sensitization Study

ID: NCT01327040
Status: Active, not recruiting
Phase: N/A
Start Date: October 01, 2010
First Submitted: March 30, 2011
Last Updated: January 16, 2018
Results: N/A
Sponsors & Collaborators: Brigham and Women's Hospital, National Heart, Lung, and Blood Institute (NHLBI)
Location: United States
Conditions: Chronobiology Disorders, Circadian Rhythm Disorders, Sleep Disorders, Circadian Rhythm
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Study Description

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 Description

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.

The 13-day inpatient studies the investigators propose will examine the effect on the human circadian system of different durations of dim-light sensitization prior to a standardized light treatment. These results will be compared within subjects in a randomized cross-over design study in which each subject will receive a control treatment and a light treatment with prior dim-light sensitization. The investigators will also include circadian phase disorder patients to test these mechanisms in the target patient population. Our findings will provide an important step in understanding how new knowledge about the circadian photoreceptive system can be used to refine and provide better treatment options for circadian rhythm disorders.
Condition or disease Intervention/treatment Phase

Chronobiology Disorders

Circadian Rhythm Disorders

Sleep Disorders, Circadian Rhythm

Other: light exposure
Other Names
N/A

Tracking Information

First Submitted DateMarch 30, 2011
Last Update Posted DateJanuary 16, 2018
Start DateOctober 01, 2010
Anticipated Completion DateDecember 01, 2018
Primary Completion DateDecember 01, 2015
Results First Submitted DateN/A
Received Results Disposit DateN/A

Current Primary Outcome Measures

  • circadian phase timing [Time Frame: During inpatient study, on days 6-7 and 11-12]

    timing of circadian phase as assessed using melatonin and temperature data

Original Primary Outcome Measures

Not Available

Current Secondary Outcome Measures

  • melatonin suppression [Time Frame: During inpatient study, on days 6-7 and 11-12]

    percent of melatonin suppression

Original Secondary Outcome Measures

Not Available

Study Design

Brief TitleLight Sensitization Study
Official TitleSensitization 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 Description

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.

The 13-day inpatient studies the investigators propose will examine the effect on the human circadian system of different durations of dim-light sensitization prior to a standardized light treatment. These results will be compared within subjects in a randomized cross-over design study in which each subject will receive a control treatment and a light treatment with prior dim-light sensitization. The investigators will also include circadian phase disorder patients to test these mechanisms in the target patient population. Our findings will provide an important step in understanding how new knowledge about the circadian photoreceptive system can be used to refine and provide better treatment options for circadian rhythm disorders.

Study TypeInterventional
Study PhaseN/A
Estimated Enrollment
40
Allocation
Randomized
Interventional Model
Crossover Assignment
Masking
None
Primary Purpose
Basic Science
Conditions
Chronobiology Disorders
Circadian Rhythm Disorders
Sleep Disorders, Circadian Rhythm
Target Follow-Up Duration N/A
Biospecimen:
N/A
Sampling MethodN/A
Study PopulationN/A
Intervention
Other: light exposure

12-hour light exposure of approximately 200 lux

Other Names
Study Groups/Cohorts
sensitization duration 1.375h
This group will experience a 1.375h sensitization duration prior to the 12h light exposure

sensitization duration 5.5h
This group will experience a 5.5h sensitization duration prior to the 12h light exposure

sensitization duration 22h
This group will experience a 22h sensitization duration prior to the 12h light exposure

sensitization duration 0.33h
This group will experience a 0.33h sensitization duration prior to the 12h light exposure

Study Arms
Experimental sensitization duration 0.33h
This group will experience a 0.33h sensitization duration prior to the 12h light exposure
Other : light exposure
12-hour light exposure of approximately 200 lux

Experimental sensitization duration 1.375h
This group will experience a 1.375h sensitization duration prior to the 12h light exposure
Other : light exposure
12-hour light exposure of approximately 200 lux

Experimental sensitization duration 22h
This group will experience a 22h sensitization duration prior to the 12h light exposure
Other : light exposure
12-hour light exposure of approximately 200 lux

Experimental sensitization duration 5.5h
This group will experience a 5.5h sensitization duration prior to the 12h light exposure
Other : light exposure
12-hour light exposure of approximately 200 lux

Arm Intervention/Treatment
Experimental sensitization duration 0.33h
This group will experience a 0.33h sensitization duration prior to the 12h light exposure
Other : light exposure
Experimental sensitization duration 1.375h
This group will experience a 1.375h sensitization duration prior to the 12h light exposure
Other : light exposure
Experimental sensitization duration 22h
This group will experience a 22h sensitization duration prior to the 12h light exposure
Other : light exposure
Experimental sensitization duration 5.5h
This group will experience a 5.5h sensitization duration prior to the 12h light exposure
Other : light exposure

Recruitment Information

Recruitment Status:Active, not recruiting
Enrollment40
Completion DateDecember 01, 2018
Eligibility Criteria: Inclusion Criteria:
- healthy adults with conventional and regular sleep-wake timing
- non-smokers
- completion of medical, psychological, ophthalmological, and sleep screening tests
- able to spend 13 consecutive days/nights in the laboratory

Exclusion Criteria:
- history of neurological or psychiatric disorder
- history of eye injury, eye surgery, or visual disorder (corrective lenses are acceptable)
- history of sleep disorder or regular use of sleep-promoting medication
- current prescription, herbal, or over-the-counter medication use (oral contraceptives are acceptable)
GenderAll
Age21 Years to 30 Years
Accepts Healthy VolunteersAccepts Healthy Volunteers
Contacts
Not Available
Listed Location Countries
United States

Administrative Information

NCT Number:NCT01327040
Other Study ID Numbers
2010-P-000346
R01HL094654
Has Data Monitoring CommitteeNo
U.S. FDA-regulated Product Studies a U.S. FDA-regulated Drug Product: No
Studies a U.S. FDA-regulated Device Product: No
Device Product Not Approved or Cleared by U.S. FDA: No
IPD Sharing Statement
Not Available
Responsible PartyJeanne Duffy, Brigham and Women's Hospital
Study Sponsor
Brigham and Women's Hospital
Collaborators
National Heart, Lung, and Blood Institute (NHLBI)
Investigators
Principal Investigator
Charles A Czeisler, PhD, MD
Brigham and Women's Hospital
Study Director
Jeanne F Duffy, PhD
Brigham and Women's Hospital