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Light Sensitization Study

This study is ongoing, but not recruiting participants.
Sponsor:
ClinicalTrials.gov Identifier:
NCT01327040
First Posted: April 1, 2011
Last Update Posted: January 16, 2017
The safety and scientific validity of this study is the responsibility of the study sponsor and investigators. Listing a study does not mean it has been evaluated by the U.S. Federal Government. Read our disclaimer for details.
Collaborator:
National Heart, Lung, and Blood Institute (NHLBI)
Information provided by (Responsible Party):
Jeanne Duffy, Brigham and Women's Hospital
  Purpose
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.

Condition Intervention
Chronobiology Disorders Circadian Rhythm Disorders Sleep Disorders, Circadian Rhythm Other: light exposure

Study Type: Interventional
Study Design: Allocation: Randomized
Intervention Model: Crossover Assignment
Masking: None (Open Label)
Primary Purpose: Basic Science
Official Title: Sensitization of Human Circadian Responses to Light

Further study details as provided by Jeanne Duffy, Brigham and Women's Hospital:

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


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


Estimated Enrollment: 40
Study Start Date: October 2010
Estimated Study Completion Date: December 2017
Primary Completion Date: December 2015 (Final data collection date for primary outcome measure)
Arms Assigned Interventions
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 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
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 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

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.

  Eligibility

Information from the National Library of Medicine

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Ages Eligible for Study:   21 Years to 30 Years   (Adult)
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   Yes
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)
  Contacts and Locations
Information from the National Library of Medicine

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.

Please refer to this study by its ClinicalTrials.gov identifier (NCT number): NCT01327040


Locations
United States, Massachusetts
Brigham and Women's Hospital
Boston, Massachusetts, United States, 02115
Sponsors and Collaborators
Brigham and Women's Hospital
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
  More Information

Responsible Party: Jeanne Duffy, Associate Neuroscientist, Brigham and Women's Hospital
ClinicalTrials.gov Identifier: NCT01327040     History of Changes
Other Study ID Numbers: 2010-P-000346
R01HL094654 ( U.S. NIH Grant/Contract )
First Submitted: March 30, 2011
First Posted: April 1, 2011
Last Update Posted: January 16, 2017
Last Verified: January 2017
Individual Participant Data (IPD) Sharing Statement:
Plan to Share IPD: No

Keywords provided by Jeanne Duffy, Brigham and Women's Hospital:
light
melatonin
circadian
delayed sleep phase disorder
circadian light sensitivity
circadian timing system

Additional relevant MeSH terms:
Disease
Sleep Wake Disorders
Parasomnias
Chronobiology Disorders
Sleep Disorders, Circadian Rhythm
Pathologic Processes
Nervous System Diseases
Neurologic Manifestations
Signs and Symptoms
Mental Disorders
Dyssomnias
Occupational Diseases