Sleep Length and Circadian Regulation in Humans (HAM)

This study is ongoing, but not recruiting participants.
Sponsor:
Collaborator:
Information provided by (Responsible Party):
Helen Burgess, Rush University Medical Center
ClinicalTrials.gov Identifier:
NCT00843843
First received: February 12, 2009
Last updated: January 15, 2014
Last verified: January 2014
  Purpose

This research will examine why sleep restriction reduces the body clock's response to bright light. The results will enable the optimization of the bright light treatment of people who suffer from circadian rhythm sleep disorders, which include shift work sleep disorder, jet lag, delayed sleep phase syndrome and winter depression, thereby improving public health and safety, well-being, mood, mental function, and quality of life.


Condition Intervention
Sleep Disorders
Device: Bright light box

Study Type: Interventional
Study Design: Allocation: Randomized
Endpoint Classification: Efficacy Study
Intervention Model: Crossover Assignment
Masking: Single Blind (Subject)
Primary Purpose: Basic Science
Official Title: Sleep Length and Circadian Regulation in Humans

Resource links provided by NLM:


Further study details as provided by Rush University Medical Center:

Primary Outcome Measures:
  • Dim Light Melatonin Onset [ Time Frame: 1-2 weeks ] [ Designated as safety issue: No ]

Secondary Outcome Measures:
  • Psychomotor Vigilance [ Time Frame: 1-2 weeks ] [ Designated as safety issue: No ]

Estimated Enrollment: 67
Study Start Date: March 2008
Estimated Study Completion Date: February 2014
Estimated Primary Completion Date: February 2014 (Final data collection date for primary outcome measure)
Arms Assigned Interventions
Active Comparator: 9 hour sleep Device: Bright light box
Bright light of about 5000 lux, administered while sitting at a desk.
Active Comparator: 3 hour nap and 6 hour sleep Device: Bright light box
Bright light of about 5000 lux, administered while sitting at a desk.

Detailed Description:

Millions of Americans suffer from circadian rhythm sleep disorders, which include shift work sleep disorder, jet lag, delayed sleep phase syndrome and possibly winter depression. These conditions are typically characterized by persistent insomnia and/or excessive daytime sleepiness, impaired performance, and gastrointestinal distress. These negative symptoms result from a misalignment between the timing of the external social world and the timing of the internal circadian (body) clock. Circadian rhythm sleep disorders are effectively treated with bright light, which phase shifts the circadian clock, thereby realigning it with the timing of the external social world.

It is widely recognized that social influences have led to an increasing prevalence of sleep restriction in modern society. We recently demonstrated for the first time that short sleep episodes, when compared to long sleep episodes, markedly reduce phase advances to bright light. Thus when people cut their sleep short, they inadvertently reduce their circadian responsiveness to bright light. The mechanism(s) behind these reduced phase shifts to light are unknown. However, there are at least two aspects of short sleep episodes that could be responsible for this effect. First, short sleep episodes are associated with partial sleep deprivation. Second, as humans sleep with their eyes closed and are usually exposed to light when awake, short sleep episodes are also associated with short dark lengths. Our overall goal is to determine the biobehavioral mechanisms by which short sleep episodes impair phase shifts to bright light. Specific Aim 1 is to determine the effect of partial sleep deprivation on phase advances to light, while controlling for dark length. Specific Aim 2 is to determine the effect of short dark lengths on phase advances to light while minimizing sleep deprivation. We will estimate the timing of the human circadian clock by measuring salivary melatonin, a neuroendocrine hormone released from the pineal gland, and collecting measures of sleep via actigraphy, and sleepiness, mood, gastrointestinal distress and cognitive performance via computerized assessment.

Characterization of the separate effects of sleep deprivation and dark length on circadian phase shifts to light in humans is critical to understanding how humans respond to light during their daily life activities. Furthermore, the findings of this research will produce important and practical recommendations for avoiding decrements to phase shifts to light, thereby optimizing the bright light treatment of circadian rhythm sleep disorders, and thus improving public health and safety, well-being, mood, cognitive function, and quality of life.

  Eligibility

Ages Eligible for Study:   18 Years to 45 Years
Genders Eligible for Study:   Both
Accepts Healthy Volunteers:   Yes
Criteria

Inclusion Criteria:

  • healthy adult volunteers

Exclusion Criteria:

  • color blindness with the Ishihara test
  • obese people (BMI > 30)
  Contacts and Locations
Choosing to participate in a study is an important personal decision. Talk with your doctor and family members or friends about deciding to join a study. To learn more about this study, you or your doctor may contact the study research staff using the Contacts provided below. For general information, see Learn About Clinical Studies.

Please refer to this study by its ClinicalTrials.gov identifier: NCT00843843

Locations
United States, Illinois
Biological Rhythms Research Laboratory, RUMC
Chicago, Illinois, United States, 60612
Sponsors and Collaborators
Rush University Medical Center
Investigators
Principal Investigator: Helen Burgess, PhD Rush University Medical Center
  More Information

No publications provided

Responsible Party: Helen Burgess, Associate Professor, Rush University Medical Center
ClinicalTrials.gov Identifier: NCT00843843     History of Changes
Other Study ID Numbers: HL083971, HL083971
Study First Received: February 12, 2009
Last Updated: January 15, 2014
Health Authority: United States: Institutional Review Board

Keywords provided by Rush University Medical Center:
Circadian Rhythms

Additional relevant MeSH terms:
Sleep Disorders
Parasomnias
Nervous System Diseases
Neurologic Manifestations
Signs and Symptoms
Mental Disorders

ClinicalTrials.gov processed this record on July 23, 2014