Light Sensitization Study

This study is currently recruiting participants.
Verified February 2013 by Brigham and Women's Hospital
Sponsor:
Collaborator:
Information provided by (Responsible Party):
Jeanne Duffy, Brigham and Women's Hospital
ClinicalTrials.gov Identifier:
NCT01327040
First received: March 30, 2011
Last updated: February 20, 2013
Last verified: February 2013
  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: Open Label
Primary Purpose: Basic Science
Official Title: Sensitization of Human Circadian Responses to Light

Resource links provided by NLM:


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

Primary Outcome Measures:
  • circadian phase timing [ Time Frame: During inpatient study, on days 6-7 and 11-12 ] [ Designated as safety issue: No ]
    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 ] [ Designated as safety issue: No ]
    percent of melatonin suppression


Estimated Enrollment: 40
Study Start Date: October 2010
Estimated Study Completion Date: June 2014
Estimated Primary Completion Date: June 2014 (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

Ages Eligible for Study:   21 Years to 30 Years
Genders Eligible for Study:   Both
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
Please refer to this study by its ClinicalTrials.gov identifier: NCT01327040

Contacts
Contact: Kelly Ward 617-525-8719 sleepstudy@partners.org
Contact: Jeanne F Duffy, PhD 617-732-4013 jduffy@rics.bwh.harvard.edu

Locations
United States, Massachusetts
Brigham and Women's Hospital Recruiting
Boston, Massachusetts, United States, 02115
Contact: David Klements    617-525-8719    sleepstudy@partners.org   
Sponsors and Collaborators
Brigham and Women's Hospital
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

No publications provided

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
Study First Received: March 30, 2011
Last Updated: February 20, 2013
Health Authority: United States: Institutional Review Board

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

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

ClinicalTrials.gov processed this record on April 15, 2014