<clinical_study>
  <!-- This xml conforms to an XML Schema at:
    https://clinicaltrials.gov/ct2/html/images/info/public.xsd -->
  <required_header>
    <download_date>ClinicalTrials.gov processed this data on September 20, 2023</download_date>
    <link_text>Link to the current ClinicalTrials.gov record.</link_text>
    <url>https://clinicaltrials.gov/ct2/show/NCT03758768</url>
  </required_header>
  <id_info>
    <org_study_id>271561</org_study_id>
    <nct_id>NCT03758768</nct_id>
  </id_info>
  <brief_title>The Effects of a Blue Monochromatic Light Intervention on Evening-type Individuals' Sleep and Circadian Rhythms</brief_title>
  <official_title>The Effects of a Blue Monochromatic Light Intervention on Evening-type Individuals' Sleep and Circadian Rhythms</official_title>
  <sponsors>
    <lead_sponsor>
      <agency>University of Bergen</agency>
      <agency_class>Other</agency_class>
    </lead_sponsor>
  </sponsors>
  <source>University of Bergen</source>
  <oversight_info>
    <has_dmc>Yes</has_dmc>
    <is_fda_regulated_drug>No</is_fda_regulated_drug>
    <is_fda_regulated_device>No</is_fda_regulated_device>
  </oversight_info>
  <brief_summary>
    <textblock>
      The present project is aimed to contribute with new knowledge concerning how light conditions&#xD;
      in the physical environment can be manipulated to alter the sleep and circadian rhythms of&#xD;
      individuals with an evening-type circadian rhythm. More precisely, the study will explore&#xD;
      whether exposure to blue light (compared to a full spectrum light control condition) during&#xD;
      the morning hours advance the circadian rhythms of evening-type individuals, towards that&#xD;
      which is more similar to the daily rhythm of morning-type individuals. This study is&#xD;
      important as it has been found that evening-type adolescents and adults are at higher risk of&#xD;
      poor academic performance and demonstrate lower intellectual performance when tested at their&#xD;
      nonoptimal early times of day, and given the fact that most schools and workplaces structure&#xD;
      their working hours during such early hours of the day. Such an intervention could thus help&#xD;
      evening-type individuals better adjust to the different early day requirements that they are&#xD;
      exposed to. The project involves a three-day intervention where participants will be exposed&#xD;
      to blue monochromatic light, administered through ceiling mounted light emitting diode&#xD;
      (LED)-based room lighting, in the early hours of each morning for a duration of 60 min. The&#xD;
      participants' sleep, circadian rhythm and waking function will be assessed both objectively&#xD;
      and subjectively. The effects of the intervention are transferable to real life educational&#xD;
      and work settings and can thus be applied in naturalistic settings. The intervention is based&#xD;
      on the new laboratory infrastructure available at the sleep laboratory situated in Christies&#xD;
      gate 12.&#xD;
    </textblock>
  </brief_summary>
  <detailed_description>
    <textblock>
      Background:&#xD;
&#xD;
      Morningness/eveningness is a phenomenon that reflects the tendency to be an &quot;early morning&#xD;
      bird&quot; or a &quot;late night owl&quot; and is thus a source of inter-individual variation in timing of&#xD;
      sleep and other behaviors. Evening- and morning-type individuals demonstrate differences that&#xD;
      derive internally regarding the circadian phase of their endogenous biological clock. A&#xD;
      certain group of individuals referred to as morning-type individuals have been consistently&#xD;
      found to perform better in the morning, whereas evening-type individuals appear to be more&#xD;
      alert and perform better in the evening. Morning-type individuals have earlier bed- and rise&#xD;
      times than evening-types, while evening-type individuals have been known to report&#xD;
      significantly later bed- and rise-times compared to morning-type individuals. In addition,&#xD;
      evening-type adolescents have been known to demonstrate poorer academic and intellectual&#xD;
      performances during their nonpreferred, i.e., early hours of the day.&#xD;
&#xD;
      Circadian rhythms are known as biological processes that display endogenous, entrainable&#xD;
      oscillations in a period of about 24 hours. These rhythms have been found to be controlled by&#xD;
      the circadian pacemaker, which is located in the suprachiasmatic nuclei (SCN) of the&#xD;
      hypothalamus. These 24-hour rhythms manifest themselves in an observable manner within&#xD;
      numerous physiological measures, such as the sleep-wake cycle, the core body temperature, and&#xD;
      the excretion of hormones such as melatonin. The core body temperature falls during the night&#xD;
      and reaches its lowest point (nadir) in the early morning, after which it starts to rise&#xD;
      again. Melatonin secretion follows a curve which is almost inverse compared to the core body&#xD;
      temperature rhythm, and is sensitive to light exposure which inhibits melatonin secretion.&#xD;
      Melatonin either in plasma, saliva or urine is regarded as an objective marker of circadian&#xD;
      rhythms, of which the dim light melatonin onset (time when melatonin reaches 4 pg/ml in&#xD;
      saliva) is the most commonly used parameter.&#xD;
&#xD;
      Sleep is known to be most easily initiated when the core body temperature is falling and as&#xD;
      the melatonin level is rising. It is also known to be most easily initiated in a timeframe of&#xD;
      six hours before nadir until a couple of hours after nadir of the core body temperature.&#xD;
&#xD;
      Evening-type individuals experience increased sleepiness and poorer performances during the&#xD;
      early hours of the morning, as there is a mismatch between their circadian rhythms and their&#xD;
      requirement of being awake at such early hours. Sleepiness is known to have severe&#xD;
      implications for performance.&#xD;
&#xD;
      However, as mentioned, the SCN outputs are entrainable and light is the strongest time-giver&#xD;
      for individuals' circadian pacemakers. Thus, the timing of light exposure has the potential&#xD;
      to either phase advance or phase delay one's circadian rhythm. Exposure to light in the hours&#xD;
      before nadir, during the evening, will lead to individuals delaying their circadian rhythm.&#xD;
      On the other side, exposure to light in the hours after nadir, during the morning hours, has&#xD;
      the potential to phase advance individuals' circadian rhythms. Light can shift the circadian&#xD;
      phase, but this effect is dependent on the timing of light, duration of light exposure, and&#xD;
      the intensity of light where higher intensities have been demonstrated to be associated with&#xD;
      greater effects. Another property of light concerns the wavelengths that it emits, where blue&#xD;
      light has been shown to produce significantly stronger phase shifting effects than lights of&#xD;
      other wavelengths of the visible spectrum. The effects of blue-light on the circadian system&#xD;
      has been attributed to a photoresponsive cell population in the retina that contains the&#xD;
      photopigment melanopsin, which is highly sensitive to blue light. These cells send signals&#xD;
      directly to the SCN, and also form connections to areas associated with wakefulness such as&#xD;
      the striatum and the brain stem. The sensitivity to melanopsin has been demonstrated to be&#xD;
      highest in a blue light range around 460 nm.&#xD;
&#xD;
      To the best of our knowledge, no study has been conducted to test the effects of a blue&#xD;
      monochromatic light intervention administered via standard room lightning on phase&#xD;
      advancement of the circadian rhythms of evening-type individuals. Consequently, our aim is to&#xD;
      assess whether blue light as compared to standard white light, administered via standard room&#xD;
      lightning, can alter the sleep and circadian rhythm of evening-type individuals, causing a&#xD;
      phase advance.&#xD;
&#xD;
      Hypothesis:&#xD;
&#xD;
      Three consecutive mornings of one hour exposure to monochromatic light (40 lx, irradiance =&#xD;
      88,79 µW/cm2) with peak wavelength of 455 nm (blue light) will, compared to full spectrum&#xD;
      light (2500 Kelvin) with equal photon flux as the blue light: a) lead to a phase advance of&#xD;
      the circadian rhythm of evening-type individuals; b) increase waking function assessed with&#xD;
      subjective and objective measures in the morning; and c) decrease participants self-reported&#xD;
      sleepiness in the morning, d) reduce sleep onset latency and e) advance sleep onset time.&#xD;
&#xD;
      We will adjust the light intensity to make sure that the photon energy is the same across the&#xD;
      two conditions.&#xD;
&#xD;
      Methods&#xD;
&#xD;
      Sample and procedure:&#xD;
&#xD;
      Our aim is to recruit a sample of minimum 34 participants from the University of Bergen.&#xD;
      Inclusion criteria is scoring below 42 on the Horne-Östberg Morningness-Eveningness&#xD;
      Questionnaire, as this categorizes moderate and definitely evening types. Participants will&#xD;
      be excluded if a positive case is indicated on the Mood Disorder Questionnaire (MDQ),&#xD;
      indicating the presence or history of bipolar disorder. Participants will also be excluded if&#xD;
      they have worked night shifts during the past three months. The participants will be exposed&#xD;
      to the blue light intervention in a randomized, blinded, controlled study. The participants&#xD;
      will be assessed with subjective and objective measures of sleep for 3 days (Tuesday -&#xD;
      Thursday) a week before the three-day blue light intervention. They will also be assessed&#xD;
      with the same subjective and objective measures during the three-day intervention period.&#xD;
      More precisely, sleep will be assessed by actigraphy and sleep diary. One day before the&#xD;
      intervention and one day after the intervention, circadian rhythm will be measured by saliva&#xD;
      samples for estimation of dim light melatonin onset. Flexibility will also be measured before&#xD;
      intervention through the Circadian Type Inventory. Waking function will be assessed on the&#xD;
      days the intervention is given with the Karolinska Sleepiness Scale and Psychomotor Vigilance&#xD;
      Task.&#xD;
&#xD;
      Instruments/measures:&#xD;
&#xD;
      Circadian Type Inventory: an instrument with two factors. Individuals scoring high on the&#xD;
      first dimension (Flexible/Rigid) are more flexible in their ability to stay awake at odd&#xD;
      times of day or night. Those who score high on the second factor (Languid/Vigorous) tend to&#xD;
      report difficulty in overcoming drowsiness, especially in the morning. CTI will be&#xD;
      distributed to participants before the light intervention.&#xD;
&#xD;
      Munich ChronoType Questionnaire: a useful tool for determining chronotype based on sleep&#xD;
      behaviors, such as bed- and rise-times, clock time when one becomes fully awake, in addition&#xD;
      to some other points (e.g., sleep latency). MCTQ will be distributed to participants before&#xD;
      the light intervention.&#xD;
&#xD;
      The Horne-Östberg Morningness-Eveningness Questionnaire (MEQ): a test that has been widely&#xD;
      used to assess morningness-eveningness. MEQ will be distributed to participants for screening&#xD;
      purposes.&#xD;
&#xD;
      Mood Disorder Questionnaire (MDQ): MDQ is a validated self-report instrument that screens for&#xD;
      the presence of a lifetime history of bipolar disorder. It contains 13 yes/no items that&#xD;
      cover topics such as mood, self-confidence, energy, sociability, interest in sex,&#xD;
      loquaciousness, distractibility, and other behaviors. There are in addition two questions&#xD;
      assessing whether the symptoms ever co-occurred and to which degree the symptoms caused&#xD;
      functional impairment. A positive case entails endorsement of 7 or more of the 13 symptoms,&#xD;
      endorsement of the co-occurrence item and reporting moderate or serious degree of functional&#xD;
      impairment. The MDQ will only be administered for screening purposes at baseline.&#xD;
&#xD;
      Actigraphy: Wrist-worn accelerometers and clocks to be worn during the same period as the&#xD;
      sleep diary. Data can be converted to objective sleep parameters. This watch will be worn the&#xD;
      week before intervention for three days, on the night before Wednesday, Thursday and Friday.&#xD;
      It will also be worn in the intervention week on the three intervention days, on the night&#xD;
      before Wednesday, Thursday and Friday.&#xD;
&#xD;
      Sleep diary: Daily subjective estimates of bedtime, rise-time, sleep latency, number of&#xD;
      awakenings, wake time after sleep onset, final awakening time, rise time, total sleep time,&#xD;
      sleep efficiency, sleep quality and daytime functioning.&#xD;
&#xD;
      The questionnaire will be distributed to the participants the week before intervention for&#xD;
      three days, on the night before Wednesday, Thursday and Friday. It will also be given in the&#xD;
      intervention week on the three intervention days, on the night before Wednesday, Thursday and&#xD;
      Friday. Two of the questions are filled before the participants go to bed, and the rest is&#xD;
      filled when they wake up in the morning.&#xD;
&#xD;
      Dim light melatonin onset (DLMO): DLMO will be assessed by collecting saliva samples every&#xD;
      hour in the evening, starting from 19:00 until one hour after normal bedtime. DLMO samples&#xD;
      will be collected one day before the intervention and the day after the intervention period.&#xD;
      Saliva collection and analyses will follow procedures previously used by our research group.&#xD;
      Blue light blocker glasses will be worn (from one hour prior to the first sample) in order to&#xD;
      prevent melatonin suppression during saliva sampling. DLMO will be analyzed with&#xD;
      enzyme-linked immunosorbent assay (ELISA) (direct saliva melatonin from Bühlmann&#xD;
      Laboratories, Schöonenbuch, Switzerland). The analytical sensitivity of this kit is 0.5 pg/ml&#xD;
      and functional sensitivity is 1.6-20.5 pg/ml, with an interassay coefficient of variation of&#xD;
      &lt;12.6%. Samples will be analyzed with a Wallac plate reader from Perkin Elmer Inc. (Waltham,&#xD;
      MA, USA).&#xD;
&#xD;
      Karolinska Sleepiness Scale (KSS): KSS comprises a single item assessing state sleepiness on&#xD;
      a scale from 1 to 9. This instrument will be given in the laboratory on the days of the light&#xD;
      intervention. It will be given for a total of six times per participant, twice on each&#xD;
      intervention day, the first immediately when the participants come to the laboratory to&#xD;
      receive the intervention, and the second after they have received one hour of light, before&#xD;
      they leave the laboratory.&#xD;
&#xD;
      Psychomotor Vigilance Task (PVT): a 10-minute reaction-time test that provides a measure of&#xD;
      sustained attention will be completed by the participants during light exposure in the&#xD;
      laboratory. The participant simply responds to stimuli given on a display by pressing a&#xD;
      button as soon as possible. PVT is especially sensitive to sleep loss and fatigue. PVT will&#xD;
      be given to participants on the three days of light intervention.&#xD;
&#xD;
      Statistical analysis/power analysis:&#xD;
&#xD;
      A 2 (Time; pre vs post) x 2 (Group; blue vs. full spectrum light) ANOVA will be used for&#xD;
      analyzing the results. Power analysis was conducted with G*Power, version 3.17. Setting the&#xD;
      effect size to medium (d=0.50), power to .80, alpha to .05, r between repeated measures to&#xD;
      .50, shows that 34 participants will be needed in order to detect a significant Time x Group&#xD;
      interaction.&#xD;
    </textblock>
  </detailed_description>
  <overall_status>Completed</overall_status>
  <start_date type="Actual">September 25, 2018</start_date>
  <completion_date type="Actual">October 22, 2018</completion_date>
  <primary_completion_date type="Actual">October 22, 2018</primary_completion_date>
  <phase>N/A</phase>
  <study_type>Interventional</study_type>
  <has_expanded_access>No</has_expanded_access>
  <study_design_info>
    <allocation>Randomized</allocation>
    <intervention_model>Parallel Assignment</intervention_model>
    <intervention_model_description>Randomized, controlled, single-blinded trial.</intervention_model_description>
    <primary_purpose>Treatment</primary_purpose>
    <masking>Double (Participant, Investigator)</masking>
    <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.&#xD;
Although the participants can see the type of light they receive, they have no knowledge of the study hypotheses.</masking_description>
  </study_design_info>
  <primary_outcome>
    <measure>Change scores from baseline to post-intervention in Dim light melatonin onset (DLMO)</measure>
    <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)</time_frame>
    <description>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).&#xD;
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.</description>
  </primary_outcome>
  <primary_outcome>
    <measure>Change scores of Feeling of Morning Wakefulness, measured by Sleep Diary</measure>
    <time_frame>Tuesday, Wednesday and Thursday (baseline; week before intervention); Tuesday, Wednesday and Thursday (week of light intervention)</time_frame>
    <description>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.&#xD;
Since the comparison is made across days/measurement points, only one composite parameter for each condition will be calculated.</description>
  </primary_outcome>
  <primary_outcome>
    <measure>Psychomotor Vigilance Task (PVT)</measure>
    <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.</time_frame>
    <description>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 &amp; Roach, 2005).&#xD;
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.&#xD;
Since the comparison is made across days/measurement points, only one composite parameter for each condition will be calculated.</description>
  </primary_outcome>
  <primary_outcome>
    <measure>Karolinska Sleepiness Scale (KSS)</measure>
    <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.</time_frame>
    <description>KSS comprises a single item assessing state sleepiness on a scale from 1 (very rested) to 9 (very sleepy). (Aakerstedt &amp; 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.&#xD;
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.</description>
  </primary_outcome>
  <secondary_outcome>
    <measure>Changes scores in Sleep Length</measure>
    <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.</time_frame>
    <description>Based on sleep diary (subjective measure of sleep length) and actigraphy (objective measure of sleep length).&#xD;
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.&#xD;
Since the comparison is made across days/measurement points, only one composite parameter for each condition will be calculated.</description>
  </secondary_outcome>
  <secondary_outcome>
    <measure>Change scores in Sleep Onset Time</measure>
    <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.</time_frame>
    <description>Based on sleep diary (subjective measure of sleep onset time) and actigraphy (objective measure of sleep onset time).&#xD;
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.&#xD;
Since the comparison is made across days/measurement points, only one composite parameter for each condition will be calculated.</description>
  </secondary_outcome>
  <secondary_outcome>
    <measure>Changes scores in Wake-up Time</measure>
    <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.</time_frame>
    <description>Based on sleep diary (subjective measure of wake-up time) and actigraphy (objective measure of wake-up time).&#xD;
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.&#xD;
Since the comparison is made across days/measurement points, only one composite parameter for each condition will be calculated.</description>
  </secondary_outcome>
  <number_of_arms>2</number_of_arms>
  <enrollment type="Actual">34</enrollment>
  <condition>Circadian Rhythm Sleep Disorder, Delayed Sleep Phase</condition>
  <condition>Sleep</condition>
  <arm_group>
    <arm_group_label>Blue monochromatic light</arm_group_label>
    <arm_group_type>Experimental</arm_group_type>
    <description>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.</description>
  </arm_group>
  <arm_group>
    <arm_group_label>Full spectrum light control condition</arm_group_label>
    <arm_group_type>Active Comparator</arm_group_type>
    <description>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.&#xD;
We will adjust the light intensity to make sure that the photon energy is the same across the two conditions.</description>
  </arm_group>
  <intervention>
    <intervention_type>Other</intervention_type>
    <intervention_name>Blue light exposure</intervention_name>
    <description>Light administered through ceiling mounted light emitting diode (LED)-based room lighting.</description>
    <arm_group_label>Blue monochromatic light</arm_group_label>
  </intervention>
  <intervention>
    <intervention_type>Other</intervention_type>
    <intervention_name>Full spectrum light exposure</intervention_name>
    <description>Light administered through ceiling mounted light emitting diode (LED)-based room lighting.</description>
    <arm_group_label>Full spectrum light control condition</arm_group_label>
  </intervention>
  <eligibility>
    <criteria>
      <textblock>
        Inclusion Criteria:&#xD;
&#xD;
          -  Scoring below 42 on the Horne-Östberg Morningness-Eveningness Questionnaire, as this&#xD;
             categorizes moderate and definitely evening types (Horne &amp; Östberg, 1976).&#xD;
&#xD;
        Exclusion Criteria:&#xD;
&#xD;
          -  Participants will be excluded if a positive case is indicated on the Mood Disorder&#xD;
             Questionnaire (MDQ), indicating the presence or history of bipolar disorder.&#xD;
&#xD;
          -  Participants will also be excluded if they have worked night shifts during the past&#xD;
             three months.&#xD;
      </textblock>
    </criteria>
    <gender>All</gender>
    <minimum_age>N/A</minimum_age>
    <maximum_age>N/A</maximum_age>
    <healthy_volunteers>Accepts Healthy Volunteers</healthy_volunteers>
  </eligibility>
  <overall_official>
    <last_name>Ståle Pallesen</last_name>
    <role>Principal Investigator</role>
    <affiliation>The University of Bergen</affiliation>
  </overall_official>
  <location>
    <facility>
      <name>University of Bergen</name>
      <address>
        <city>Bergen</city>
        <state>Hordaland</state>
        <zip>5015</zip>
        <country>Norway</country>
      </address>
    </facility>
  </location>
  <location_countries>
    <country>Norway</country>
  </location_countries>
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  <verification_date>November 2018</verification_date>
  <study_first_submitted>November 20, 2018</study_first_submitted>
  <study_first_submitted_qc>November 28, 2018</study_first_submitted_qc>
  <study_first_posted type="Actual">November 29, 2018</study_first_posted>
  <last_update_submitted>November 28, 2018</last_update_submitted>
  <last_update_submitted_qc>November 28, 2018</last_update_submitted_qc>
  <last_update_posted type="Actual">November 29, 2018</last_update_posted>
  <responsible_party>
    <responsible_party_type>Sponsor</responsible_party_type>
  </responsible_party>
  <keyword>Circadian rhythm</keyword>
  <keyword>Sleep</keyword>
  <keyword>evening-type individuals</keyword>
  <keyword>morningness-eveningness</keyword>
  <keyword>blue light</keyword>
  <keyword>monochromatic light</keyword>
  <keyword>randomized controlled trial</keyword>
  <condition_browse>
    <!-- CAUTION:  The following MeSH terms are assigned with an imperfect algorithm            -->
    <mesh_term>Sleep Wake Disorders</mesh_term>
    <mesh_term>Sleep Disorders, Circadian Rhythm</mesh_term>
  </condition_browse>
  <patient_data>
    <sharing_ipd>Undecided</sharing_ipd>
  </patient_data>
  <!-- Results have not yet been posted for this study                                          -->
</clinical_study>


download date: ClinicalTrials.gov processed this data on September 20, 2023
link text: Link to the current ClinicalTrials.gov record.
url: https://clinicaltrials.gov/ct2/show/NCT03758768
org study id: 271561
nct id: NCT03758768
lead sponsor: 
has dmc: Yes
is fda regulated drug: No
is fda regulated device: No
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.
Background:

      Morningness/eveningness is a phenomenon that reflects the tendency to be an "early morning
      bird" or a "late night owl" and is thus a source of inter-individual variation in timing of
      sleep and other behaviors. Evening- and morning-type individuals demonstrate differences that
      derive internally regarding the circadian phase of their endogenous biological clock. A
      certain group of individuals referred to as morning-type individuals have been consistently
      found to perform better in the morning, whereas evening-type individuals appear to be more
      alert and perform better in the evening. Morning-type individuals have earlier bed- and rise
      times than evening-types, while evening-type individuals have been known to report
      significantly later bed- and rise-times compared to morning-type individuals. In addition,
      evening-type adolescents have been known to demonstrate poorer academic and intellectual
      performances during their nonpreferred, i.e., early hours of the day.

      Circadian rhythms are known as biological processes that display endogenous, entrainable
      oscillations in a period of about 24 hours. These rhythms have been found to be controlled by
      the circadian pacemaker, which is located in the suprachiasmatic nuclei (SCN) of the
      hypothalamus. These 24-hour rhythms manifest themselves in an observable manner within
      numerous physiological measures, such as the sleep-wake cycle, the core body temperature, and
      the excretion of hormones such as melatonin. The core body temperature falls during the night
      and reaches its lowest point (nadir) in the early morning, after which it starts to rise
      again. Melatonin secretion follows a curve which is almost inverse compared to the core body
      temperature rhythm, and is sensitive to light exposure which inhibits melatonin secretion.
      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.

      Sleep is known to be most easily initiated when the core body temperature is falling and as
      the melatonin level is rising. It is also known to be most easily initiated in a timeframe of
      six hours before nadir until a couple of hours after nadir of the core body temperature.

      Evening-type individuals experience increased sleepiness and poorer performances during the
      early hours of the morning, as there is a mismatch between their circadian rhythms and their
      requirement of being awake at such early hours. Sleepiness is known to have severe
      implications for performance.

      However, as mentioned, the SCN outputs are entrainable and light is the strongest time-giver
      for individuals' circadian pacemakers. Thus, the timing of light exposure has the potential
      to either phase advance or phase delay one's circadian rhythm. Exposure to light in the hours
      before nadir, during the evening, will lead to individuals delaying their circadian rhythm.
      On the other side, exposure to light in the hours after nadir, during the morning hours, has
      the potential to phase advance individuals' circadian rhythms. Light can shift the circadian
      phase, but this effect is dependent on the timing of light, duration of light exposure, and
      the intensity of light where higher intensities have been demonstrated to be associated with
      greater effects. Another property of light concerns the wavelengths that it emits, where blue
      light has been shown to produce significantly stronger phase shifting effects than lights of
      other wavelengths of the visible spectrum. The effects of blue-light on the circadian system
      has been attributed to a photoresponsive cell population in the retina that contains the
      photopigment melanopsin, which is highly sensitive to blue light. These cells send signals
      directly to the SCN, and also form connections to areas associated with wakefulness such as
      the striatum and the brain stem. The sensitivity to melanopsin has been demonstrated to be
      highest in a blue light range around 460 nm.

      To the best of our knowledge, no study has been conducted to test the effects of a blue
      monochromatic light intervention administered via standard room lightning on phase
      advancement of the circadian rhythms of evening-type individuals. Consequently, our aim is to
      assess whether blue light as compared to standard white light, administered via standard room
      lightning, can alter the sleep and circadian rhythm of evening-type individuals, causing a
      phase advance.

      Hypothesis:

      Three consecutive mornings of one hour exposure to monochromatic light (40 lx, irradiance =
      88,79 µW/cm2) with peak wavelength of 455 nm (blue light) will, compared to full spectrum
      light (2500 Kelvin) with equal photon flux as the blue light: a) lead to a phase advance of
      the circadian rhythm of evening-type individuals; b) increase waking function assessed with
      subjective and objective measures in the morning; and c) decrease participants self-reported
      sleepiness in the morning, d) reduce sleep onset latency and e) advance sleep onset time.

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

      Methods

      Sample and procedure:

      Our aim is to recruit a sample of minimum 34 participants from the University of Bergen.
      Inclusion criteria is scoring below 42 on the Horne-Östberg Morningness-Eveningness
      Questionnaire, as this categorizes moderate and definitely evening types. 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. The participants will be exposed
      to the blue light intervention in a randomized, blinded, controlled study. The participants
      will be assessed with subjective and objective measures of sleep for 3 days (Tuesday -
      Thursday) a week before the three-day blue light intervention. They will also be assessed
      with the same subjective and objective measures during the three-day intervention period.
      More precisely, sleep will be assessed by actigraphy and sleep diary. One day before the
      intervention and one day after the intervention, circadian rhythm will be measured by saliva
      samples for estimation of dim light melatonin onset. Flexibility will also be measured before
      intervention through the Circadian Type Inventory. Waking function will be assessed on the
      days the intervention is given with the Karolinska Sleepiness Scale and Psychomotor Vigilance
      Task.

      Instruments/measures:

      Circadian Type Inventory: an instrument with two factors. Individuals scoring high on the
      first dimension (Flexible/Rigid) are more flexible in their ability to stay awake at odd
      times of day or night. Those who score high on the second factor (Languid/Vigorous) tend to
      report difficulty in overcoming drowsiness, especially in the morning. CTI will be
      distributed to participants before the light intervention.

      Munich ChronoType Questionnaire: a useful tool for determining chronotype based on sleep
      behaviors, such as bed- and rise-times, clock time when one becomes fully awake, in addition
      to some other points (e.g., sleep latency). MCTQ will be distributed to participants before
      the light intervention.

      The Horne-Östberg Morningness-Eveningness Questionnaire (MEQ): a test that has been widely
      used to assess morningness-eveningness. MEQ will be distributed to participants for screening
      purposes.

      Mood Disorder Questionnaire (MDQ): MDQ is a validated self-report instrument that screens for
      the presence of a lifetime history of bipolar disorder. It contains 13 yes/no items that
      cover topics such as mood, self-confidence, energy, sociability, interest in sex,
      loquaciousness, distractibility, and other behaviors. There are in addition two questions
      assessing whether the symptoms ever co-occurred and to which degree the symptoms caused
      functional impairment. A positive case entails endorsement of 7 or more of the 13 symptoms,
      endorsement of the co-occurrence item and reporting moderate or serious degree of functional
      impairment. The MDQ will only be administered for screening purposes at baseline.

      Actigraphy: Wrist-worn accelerometers and clocks to be worn during the same period as the
      sleep diary. Data can be converted to objective sleep parameters. This watch will be worn the
      week before intervention for three days, on the night before Wednesday, Thursday and Friday.
      It will also be worn in the intervention week on the three intervention days, on the night
      before Wednesday, Thursday and Friday.

      Sleep diary: Daily subjective estimates of bedtime, rise-time, sleep latency, number of
      awakenings, wake time after sleep onset, final awakening time, rise time, total sleep time,
      sleep efficiency, sleep quality and daytime functioning.

      The questionnaire will be distributed to the participants the week before intervention for
      three days, on the night before Wednesday, Thursday and Friday. It will also be given in the
      intervention week on the three intervention days, on the night before Wednesday, Thursday and
      Friday. Two of the questions are filled before the participants go to bed, and the rest is
      filled when they wake up in the morning.

      Dim light melatonin onset (DLMO): DLMO will be assessed by collecting saliva samples every
      hour in the evening, starting from 19:00 until one hour after normal bedtime. DLMO samples
      will be collected one day before the intervention and the day after the intervention period.
      Saliva collection and analyses will follow procedures previously used by our research group.
      Blue light blocker glasses will be worn (from one hour prior to the first sample) in order to
      prevent melatonin suppression during saliva sampling. DLMO will be analyzed with
      enzyme-linked immunosorbent assay (ELISA) (direct saliva melatonin from Bühlmann
      Laboratories, Schöonenbuch, Switzerland). The analytical sensitivity of this kit is 0.5 pg/ml
      and functional sensitivity is 1.6-20.5 pg/ml, with an interassay coefficient of variation of
      <12.6%. Samples will be analyzed with a Wallac plate reader from Perkin Elmer Inc. (Waltham,
      MA, USA).

      Karolinska Sleepiness Scale (KSS): KSS comprises a single item assessing state sleepiness on
      a scale from 1 to 9. This instrument will be given in the laboratory on the days of the light
      intervention. It will be given for a total of six times per participant, twice on each
      intervention day, the first immediately when the participants come to the laboratory to
      receive the intervention, and the second after they have received one hour of light, before
      they leave the laboratory.

      Psychomotor Vigilance Task (PVT): 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. PVT will
      be given to participants on the three days of light intervention.

      Statistical analysis/power analysis:

      A 2 (Time; pre vs post) x 2 (Group; blue vs. full spectrum light) ANOVA will be used for
      analyzing the results. Power analysis was conducted with G*Power, version 3.17. Setting the
      effect size to medium (d=0.50), power to .80, alpha to .05, r between repeated measures to
      .50, shows that 34 participants will be needed in order to detect a significant Time x Group
      interaction.
allocation: Randomized
intervention model: Parallel Assignment
intervention model description: Randomized, controlled, single-blinded trial.
primary purpose: Treatment
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.
measure: 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)
description: 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.
measure: 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)
description: 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.
measure: 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.
description: 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.
measure: 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.
description: 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.
measure: 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.
description: 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.
measure: 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.
description: 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.
measure: 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.
description: 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.
arm group label: Blue monochromatic light
arm group type: Experimental
description: 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.
arm group label: Full spectrum light control condition
arm group type: Active Comparator
description: 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.
intervention type: Other
intervention name: Blue light exposure
description: Light administered through ceiling mounted light emitting diode (LED)-based room lighting.
arm group label: Blue monochromatic light
intervention type: Other
intervention name: Full spectrum light exposure
description: Light administered through ceiling mounted light emitting diode (LED)-based room lighting.
arm group label: Full spectrum light control condition
criteria: 
gender: All
minimum age: N/A
maximum age: N/A
healthy volunteers: Accepts Healthy Volunteers
last name: Ståle Pallesen
role: Principal Investigator
affiliation: The University of Bergen
facility: 
country: Norway
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responsible party type: Sponsor
mesh term: Sleep Wake Disorders
mesh term: Sleep Disorders, Circadian Rhythm
sharing ipd: Undecided