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The Effects of a Blue Monochromatic Light Intervention on Evening-type Individuals' Sleep and Circadian Rhythms

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ClinicalTrials.gov Identifier: NCT03758768
Recruitment Status : Completed
First Posted : November 29, 2018
Last Update Posted : November 29, 2018
Sponsor:
Information provided by (Responsible Party):
University of Bergen

Brief Summary:
The present project is aimed to contribute with new knowledge concerning how light conditions in the physical environment can be manipulated to alter the sleep and circadian rhythms of individuals with an evening-type circadian rhythm. More precisely, the study will explore whether exposure to blue light (compared to a full spectrum light control condition) during the morning hours advance the circadian rhythms of evening-type individuals, towards that which is more similar to the daily rhythm of morning-type individuals. This study is important as it has been found that evening-type adolescents and adults are at higher risk of poor academic performance and demonstrate lower intellectual performance when tested at their nonoptimal early times of day, and given the fact that most schools and workplaces structure their working hours during such early hours of the day. Such an intervention could thus help evening-type individuals better adjust to the different early day requirements that they are exposed to. The project involves a three-day intervention where participants will be exposed to blue monochromatic light, administered through ceiling mounted light emitting diode (LED)-based room lighting, in the early hours of each morning for a duration of 60 min. The participants' sleep, circadian rhythm and waking function will be assessed both objectively and subjectively. The effects of the intervention are transferable to real life educational and work settings and can thus be applied in naturalistic settings. The intervention is based on the new laboratory infrastructure available at the sleep laboratory situated in Christies gate 12.

Condition or disease Intervention/treatment Phase
Circadian Rhythm Sleep Disorder, Delayed Sleep Phase Sleep Other: Blue light exposure Other: Full spectrum light exposure Not Applicable

  Show Detailed Description

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Study Type : Interventional  (Clinical Trial)
Actual Enrollment : 34 participants
Allocation: Randomized
Intervention Model: Parallel Assignment
Intervention Model Description: Randomized, controlled, single-blinded trial.
Masking: Double (Participant, Investigator)
Masking Description:

A third-party investigator is recruited to be present during the intervention. This third-party investigator has no knowledge of the hypotheses of the study.

Although the participants can see the type of light they receive, they have no knowledge of the study hypotheses.

Primary Purpose: Treatment
Official Title: The Effects of a Blue Monochromatic Light Intervention on Evening-type Individuals' Sleep and Circadian Rhythms
Actual Study Start Date : September 25, 2018
Actual Primary Completion Date : October 22, 2018
Actual Study Completion Date : October 22, 2018

Arm Intervention/treatment
Experimental: Blue monochromatic light
Three consecutive mornings of one hour exposure to monochromatic light (20 lx, irradiance = 49.65 µW/cm2) with peak wavelength of 455 nm (blue light), with equal photon flux as the control condition.
Other: Blue light exposure
Light administered through ceiling mounted light emitting diode (LED)-based room lighting.

Active Comparator: Full spectrum light control condition

Three consecutive mornings of one hour exposure to full spectrum light (2500 Kelvin, irradiance = 37.72 µW/cm2) with equal photon flux as the blue light.

We will adjust the light intensity to make sure that the photon energy is the same across the two conditions.

Other: Full spectrum light exposure
Light administered through ceiling mounted light emitting diode (LED)-based room lighting.




Primary Outcome Measures :
  1. Change scores from baseline to post-intervention in Dim light melatonin onset (DLMO) [ Time Frame: Pre-intervention/baseline (Monday in the week of intervention - one day before the first intervention day); Post-intervention (Friday, the week of intervention - one day after last intervention day) ]

    Melatonin either in plasma, saliva or urine is regarded as an objective marker of circadian rhythms, of which the dim light melatonin onset (time when melatonin reaches 4 pg/ml in saliva) is the most commonly used parameter (Pandi-Perumal et al., 2007).

    The change score of the intervention group will be compared to the change score of the control group. Thus only one parameter will be estimated.


  2. Change scores of Feeling of Morning Wakefulness, measured by Sleep Diary [ Time Frame: Tuesday, Wednesday and Thursday (baseline; week before intervention); Tuesday, Wednesday and Thursday (week of light intervention) ]

    Change scores of the feeling of morning wakefulness across Tuesday to Thursday the week before intervention, substracted from Feeling of Morning Wakefulness across Tuesday to Thursday on the intervention week.

    Since the comparison is made across days/measurement points, only one composite parameter for each condition will be calculated.


  3. Psychomotor Vigilance Task (PVT) [ Time Frame: PVT will be given to participants on the three days of light intervention (Tuesday, Wednesday and Thursday). The average score of these three days will be obtained and compared with the control group. ]

    A 10-minute reaction-time test that provides a measure of sustained attention will be completed by the participants during light exposure in the laboratory. The participant simply responds to stimuli given on a display by pressing a button as soon as possible. PVT is especially sensitive to sleep loss and fatigue (Lamond, Dawson & Roach, 2005).

    Average scores of reaction time across Tuesday, Wednesday and Thursday (the three days of light intervention) will be calculated for the intervention group and compared to the average scores of reaction time across Tuesday, Wednesday and Thursday (the three days of light intervention for the control group.

    Since the comparison is made across days/measurement points, only one composite parameter for each condition will be calculated.


  4. Karolinska Sleepiness Scale (KSS) [ Time Frame: Given on the days of intervention (Tuesday, Wednesday, Thursday) twice on each day. First immediately when the participants enter the lab to receive the intervention, and the second after they have received one hour of light, before they leave the lab. ]

    KSS comprises a single item assessing state sleepiness on a scale from 1 (very rested) to 9 (very sleepy). (Aakerstedt & Gillberg, 1990). The minimum score is 1 (very rested) and the maximum is 9 (very sleepy). Lower values present the feeling of restedness and are thus considered to be a better outcome.

    Average score of KSS will be calculated across the three intervention days (Tuesday, Wednesday, Thursday) for the intervention group, and compared to the average score of KSS across the same three intervention days for the control group. Accordingly, only one outcome measure will be calculated per group. Thus only one parameter will be estimated.



Secondary Outcome Measures :
  1. Changes scores in Sleep Length [ Time Frame: Change scores of sleep length across Tuesday, Wednesday and Thursday the week before intervention, substracted from sleep length across Tuesday, Wednesday and Thursday on the intervention week. ]

    Based on sleep diary (subjective measure of sleep length) and actigraphy (objective measure of sleep length).

    The sleep diary consists of no pre-determined scale. It is a diary where the participants fill in a time-point (e.g. the time they went to bed, the time they turned off the lights, how long it took until they fell as asleep, and when they woke up in the morning). The measurement unit is minutes.

    Since the comparison is made across days/measurement points, only one composite parameter for each condition will be calculated.


  2. Change scores in Sleep Onset Time [ Time Frame: Change scores of sleep onset time across Tuesday, Wednesday, and Thursday the week before intervention, substracted from sleep onset time across Tuesday, Wednesday, and Thursday on the intervention week. ]

    Based on sleep diary (subjective measure of sleep onset time) and actigraphy (objective measure of sleep onset time).

    The sleep consists of items that require a time-point as the answer. E.g.: What time did you wake up, to which you can reply 09:00 or any value within a 24-hour day.

    Since the comparison is made across days/measurement points, only one composite parameter for each condition will be calculated.


  3. Changes scores in Wake-up Time [ Time Frame: Change scores of wake-up time across Tuesday, Wednesday and Thursday the week before intervention, substracted from wake-up time across Tuesday, Wednesday and Thursday on the intervention week. ]

    Based on sleep diary (subjective measure of wake-up time) and actigraphy (objective measure of wake-up time).

    The sleep diary consists of items that require a time-point as the answer. E.g.: What time did you wake up, to which you can reply 08:30 or any value within a 24-hour day.

    Since the comparison is made across days/measurement points, only one composite parameter for each condition will be calculated.




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Ages Eligible for Study:   Child, Adult, Older Adult
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   Yes
Criteria

Inclusion Criteria:

  • Scoring below 42 on the Horne-Östberg Morningness-Eveningness Questionnaire, as this categorizes moderate and definitely evening types (Horne & Östberg, 1976).

Exclusion Criteria:

  • Participants will be excluded if a positive case is indicated on the Mood Disorder Questionnaire (MDQ), indicating the presence or history of bipolar disorder.
  • Participants will also be excluded if they have worked night shifts during the past three months.

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): NCT03758768


Locations
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Norway
University of Bergen
Bergen, Hordaland, Norway, 5015
Sponsors and Collaborators
University of Bergen
Investigators
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Principal Investigator: Ståle Pallesen The University of Bergen

Publications:
Di Milia, L., Smith, P. A., & Folkard, S. (2005). A validation of the revised circadian type inventory in a working sample. Personality and Individual differences, 39(7), 1293-1305.
Escribano, C., Díaz-Morales, J. F., Delgado, P., & Collado, M. J. (2012). Morningness/eveningness and school performance among Spanish adolescents: Further evidence. Learning and Individual Differences, 22(3), 409-413.
Preckel, F., Lipnevich, A. A., Schneider, S., & Roberts, R. D. (2011). Chronotype, cognitive abilities, and academic achievement: A meta-analytic investigation. Learning and Individual Differences, 21(5), 483-492.
Randler, C., & Frech, D. (2006). Correlation between morningness-eveningness and final school leaving exams. Biological Rhythm Research, 37(3), 233-239.
Terman, M., & Terman, J. S. (2005). Light therapy. Principles and practice of sleep medicine, 4, 1424-42.

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Responsible Party: University of Bergen
ClinicalTrials.gov Identifier: NCT03758768     History of Changes
Other Study ID Numbers: 271561
First Posted: November 29, 2018    Key Record Dates
Last Update Posted: November 29, 2018
Last Verified: November 2018
Individual Participant Data (IPD) Sharing Statement:
Plan to Share IPD: Undecided

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Studies a U.S. FDA-regulated Drug Product: No
Studies a U.S. FDA-regulated Device Product: No
Keywords provided by University of Bergen:
Circadian rhythm
Sleep
evening-type individuals
morningness-eveningness
blue light
monochromatic light
randomized controlled trial
Additional relevant MeSH terms:
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Sleep Wake Disorders
Sleep Disorders, Circadian Rhythm
Nervous System Diseases
Neurologic Manifestations
Signs and Symptoms
Mental Disorders
Chronobiology Disorders
Dyssomnias
Occupational Diseases