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Chronobiology DisordersNCT01327040

Light Sensitization Study

A study testing light exposure in people with Chronobiology Disorders and Circadian Rhythm Disorders, run by Brigham and Women's Hospital at 1 site in United States.

Completed

Finished. The study has ended and is not enrolling. Results may be posted on the official record.

Official record
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Trial 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… Read more about this study

Who is it for?
Ages 21 to 30 yearsHealthy volunteers can take part
What is being tested?
light exposure
Could I receive a placebo?
No, everyone receives an active treatment
How many people
32 participants
Where
1 siteUnited States
Study dates
Oct 2010to Dec 2020
Phase
Interventional
Are there results?
None posted in the registry

Key requirements

Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.

  • Ages 21 to 30 years
  • All sexes
  • Healthy volunteers accepted
  • Adult

Who may be able to join

  • 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

Who cannot join

  • 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)

Trial locations and contacts

1 site in 1 country.

United States1 site
  • Brigham and Women's Hospital

    Boston, Massachusetts, 02115

Other trials in United States

About this study

Official title: Sensitization of Human Circadian Responses to Light

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.

Read the 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.

Being tested
light exposure
Keywords
light, melatonin, circadian, delayed sleep phase disorder, circadian light sensitivity, circadian timing system
Medical subject headings
Chronobiology Disorders, Sleep Disorders, Circadian Rhythm

What participants receive

What participants receive. In a randomised study each person is assigned to one group by chance.

  • light exposureOther

    12-hour light exposure of approximately 200 lux

Study groups in NCT01327040
Study groupRoleWhat they receive
sensitization duration 1.375hExperimentalThis group will experience a 1.375h sensitization duration prior to the 12h light exposure
Receives: Other: light exposure
sensitization duration 5.5hExperimentalThis group will experience a 5.5h sensitization duration prior to the 12h light exposure
Receives: Other: light exposure
sensitization duration 22hExperimentalThis group will experience a 22h sensitization duration prior to the 12h light exposure
Receives: Other: light exposure
sensitization duration 0.33hExperimentalThis group will experience a 0.33h sensitization duration prior to the 12h light exposure
Receives: Other: light exposure

What is being measured

The primary outcome is the main question the study is designed to answer.

  1. circadian phase timing

    timing of circadian phase as assessed using melatonin and temperature data

    Measured: During inpatient study, on days 6-7 and 11-12

Secondary outcomes (1)
  1. melatonin suppression

    percent of melatonin suppression

    Measured: During inpatient study, on days 6-7 and 11-12

Timeline

From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.

  1. First posted1 Apr 2011 (estimated)
  2. Study startOct 2010
  3. Primary completionDec 2015
  4. Study completionDec 2020

Resources

More details

For doctors and researchers: how the study is designed, who runs it, and its registry IDs.

Study design
Study type
Interventional
Phase
Phase N/A
Primary purpose
Basic science
Allocation
Randomised
Intervention model
Crossover
Masking
None (open label)
Enrolment
32 participants (actual)
IDs, dates and publications
ClinicalTrials.gov ID
NCT01327040
Sponsor's protocol ID
2010-P-000346
Other IDs
R01HL094654
Status last verified
Jun 2021
First submitted
30 Mar 2011
Last updated
1 Jul 2021
Results posted
No
Data monitoring committee
No
Individual data sharing
No

Questions about this trial

What is this clinical trial studying?

A study testing light exposure in people with Chronobiology Disorders and Circadian Rhythm Disorders, run by Brigham and Women's Hospital at 1 site in United States.

The full registered description is in the About this study section and the official record.

Who may be eligible to take part?

The sponsor lists 4 inclusion and 4 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.

Is this clinical trial currently recruiting?

The record says: finished, as of the sponsor's last update on 1 Jul 2021. Status can change between updates, so confirm with the study contact before making plans.

Where is the study taking place?

The record lists 1 site in United States. Whether a site is taking part right now should be confirmed with that site. See every site.

What are the possible benefits and risks?

They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.

Are results available for this study?

The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.

How can a doctor refer a patient or contact the research team?

The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.

What does the primary outcome measure?

circadian phase timing (time frame: During inpatient study, on days 6-7 and 11-12). It is what the study was designed to measure, not a finding.

Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?

No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.

How often is this information updated?

AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 1 Jul 2021.

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