Are Cognition and Sleep Affected by Exposure to Carbon Dioxide and Bio Effluents During Sleep?
Condition: Cognitive Impairment, Mild; Sleep; Environmental Exposure
MeSH terms: Cognitive Dysfunction
Study type: Interventional

Summary: 
      The aim of the project is to examine whether children's sleep and cognition are affected by
      exposure to CO2 and other bio effluents during sleep. The participants of the study are 36
      children recruited from local schools in Aarhus, Denmark.

      The study takes place in the climate chambers at the Department of Public Health, Aarhus
      University. These chambers allow for experimental testing on humans with advanced exposure
      generation while avoiding contamination from other sources and controlling temperature,
      humidity, noise, odor, and light.

      The children will be sleeping in the chambers under three different conditions:

        -  One night of good ventilation with a CO2 level of maximum 800 ppm

        -  One night of good ventilation with high levels of CO2 (3,000 ppm)

        -  One night of poor ventilation with high concentrations of CO2 (3000 ppm) and other bio
           effluents.

      The study is a within-group design, and groups of six children will be sleeping in the
      chambers for three nights (separated by seven days). The different groups of children are
      exposed to the conditions in a randomized order. The study is double-blinded (of security
      reasons the persons responsible for CO2 concentrations in the chambers are not blinded).

      The study takes place on schools nights. The children arrive at 6 pm and leave for school the
      morning after. In the evening the children are tested for approximately 30-40 minutes to
      measure their cognitive performance using CANTAB (Cambridge Neuropsychological Test Automated
      Battery) on iPads. After completing the test, dinner is served and the children have some
      spare time before going to bed. During night, the quality of sleep (awake time and different
      sleep stages) will be monitored using Fitbit devices. Sleep quality will also be evaluated
      using a short sleep questionnaire. The next morning the cognitive performance of the children
      will be tested again using CANTAB before the children leave for school.

      Our primary hypothesis is that children will perform worse on the cognitive test when exposed
      to high levels of CO2 and other bio effluents than compared to low levels of CO2 and bio
      effluents in a well-ventilated room. In addition to that our secondary hypotheses are:

        -  Children will perform worse on the cognitive test when exposed to high levels of CO2 and
           other bio effluents than compared to CO2 alone.

        -  Children will sleep less well in an environment with poor ventilation and high levels of
           CO2 and other bio effluents compared to sleeping in a well-ventilated room with low
           levels of CO2.

        -  Children will sleep less well in an environment with poor ventilation and high levels of
           CO2 and other bio effluents compared to sleeping in a room with high levels of CO2
           alone.

        -  Children will sleep less well and perform worse on the cognitive test when exposed to
           high levels of CO2 compared to low levels of CO2.
    


Intervention name(s): Good ventilation; Ventilation CO2; Poor Ventilation
Intervention type(s): Other; Other; Other
Intervention description(s): Good ventilation with a low concentration of CO2; CO2 High and Good ventilation; Poor ventilation with high concentrations of CO2 and bio effluents
Allocation: Randomized
Intervention model: Crossover Assignment
Intervention model description: The 36 children are divided into 6 groups of 6 children. Every group is exposed to all possible conditions (3) in a randomized order.
Masking: Quadruple (Participant, Care Provider, Investigator, Outcomes Assessor)
Primary purpose: Prevention
Keywords: cognition; sleep; carbon dioxide; bio effluents