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Completed

NCT Number: NCT02838095

Effects of Napping in Sleep-Restricted Adolescents

To examine the neurobehavioural responses to two successive cycles of sleep restriction and recovery in adolescents, and to determine the benefits of napping on cognitive performance, alertness, and mood. 57 participants, aged 15 to 19 years old, were divided into nap and no-nap groups. Both groups underwent two cycles of sleep restriction and recovery over 15 days. The nap group received an afternoon sleep opportunity lasting 1 hour.

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Key information

Conditions

Sleep Deprivation Dyssomnias Mental Disorders Nervous System Diseases Neurologic Manifestations Pathological Conditions, Signs and Symptoms Signs and Symptoms Sleep Sleep Wake Disorders

Age range

15 year–19 year

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

Duke-NUS Medical School

Singapore, 169857

About this study

57 participants (aged 15 to 19 years old) were grouped into nap and no nap groups. Both groups took part in a 15-day protocol that started with 2 9-hour adaptation and baseline nights, followed by two successive cycles of sleep restriction (5-h time-in-bed [TIB]; 01:00-06:00) and recovery (9-h TIB; 23:00-08:00) intended to simulate the weekday sleep loss and weekend attempt to 'catch up' that are familiar to high school students. The nap group received a 1-hour nap opportunity at 14:00 following each sleep-restricted night, while participants in the no nap group watched a documentary. Sleep was monitored with polysomnography on 9 selected nights. Cognitive performance, subjective sleepiness, and mood were assessed 3 times daily (10:00, 15:45, and 20:00).

All participants stayed in air-conditioned, twin-share bedrooms with en-suite bathrooms. Bedroom windows were fitted with blackout panels to ensure participants were not woken up prematurely by sunlight. Earplugs were also provided, and participants were allowed to adjust the temperature of their bedrooms to their personal comfort. 3 main meals were served each day, with snacks being provided for upon request. Caffeinated drinks, unscheduled sleep, and strenuous physical activities were prohibited.

Outside of scheduled sleep, meal, and cognitive testing times, participants spent the majority of their free time in a common room that was illuminated by natural and artificial lighting. They were allowed to read, play non-physically exerting games, watch videos, and interact with research staff and other participants. Participants were under constant supervision by the research staff.

Who can participate

Healthy volunteers accepted: Yes

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • healthy
  • no sleep disorder
  • body mass index not greater than 30

Exclusion criteria

  • smoker
  • habitual short sleeper (time in bed during term time of less than 6 hours and no sign of sleep extension of greater than 1 hour on weekends)
  • consumption of more than 5 cups of caffeinated beverages a day
  • travelling across more than 2 time zones in the month prior to the study protocol
  • diagnosed with any psychiatric conditions

Treatment and study plan

Nap

Behavioral

A 1-hour daytime nap opportunity

Primary outcomes

  1. Change in sustained attention assessed with the Psychomotor Vigilance Task from morning to afternoon and then evening from baseline days to the first and second cycles of sleep restriction and recovery

    Time frame: 3 times daily (10:00, 15:45, and 20:00) for 15 days

    Number of attention lapses (>500ms)

  2. Change in working memory assessed with the 1-back task from morning to afternoon and then evening from baseline days to the first and second cycles of sleep restriction and recovery

    Time frame: 3 times daily (10:00, 15:45, and 20:00) for 15 days

    Number of correct responses in the 1-back task

  3. Change in executive functions assessed with the 3-back task from morning to afternoon and then evening from baseline days to the first and second cycles of sleep restriction and recovery

    Time frame: 3 times daily (10:00, 15:45, and 20:00) for 15 days

    Number of correct responses in the 3-back task

  4. Change in the level of subjective sleepiness assessed with the Karolinska Sleepiness Scale from morning to afternoon and then evening from baseline days to the first and second cycles of sleep restriction and recovery

    Time frame: 3 times daily (10:00, 15:45, and 20:00) for 15 days

    Score on the Karolinska Sleepiness Scale (1-9 points)

  5. Change in positive mood assessed with the Positive and Negative Affect Scale (PANAS) from morning to afternoon and then evening from baseline days to the first and second cycles of sleep restriction and recovery

    Time frame: 3 times daily (10:00, 15:45, and 20:00) for 15 days

    Total score on the positive subscale of the PANAS

  6. Change in negative mood assessed with the Positive and Negative Affect Scale (PANAS) from morning to afternoon and then evening from baseline days to the first and second cycles of sleep restriction and recovery

    Time frame: 3 times daily (10:00, 15:45, and 20:00) for 15 days

    Total score on the negative subscale of the PANAS

  7. Change in speed of processing assessed with the Mental Arithmetic Task from morning to afternoon and then evening from baseline days to the first and second cycles of sleep restriction and recovery

    Time frame: 3 times daily (10:00, 15:45, and 20:00) for 15 days

    Number of correct responses in the task

  8. Change in speed of processing assessed with the Symbol Digit Modalities Task from morning to afternoon and then evening from baseline days to the first and second cycles of sleep restriction and recovery

    Time frame: 3 times daily (10:00, 15:45, and 20:00) for 15 days

    Number of correct responses in the task

Secondary outcomes

  1. Change in total sleep duration at night assessed with polysomnography from baseline nights to the first and second cycles of sleep restriction and recovery

    Time frame: Nocturnal sleep on nights 1 & 3 (baseline), 4, 6 & 8 (first sleep restriction period), 9 (first recovery period), 11 & 13 (second sleep restriction period), & 14 (second recovery period)

    Total duration of nocturnal sleep was determined to establish baseline sleep characteristics (first and third nights) and changes in the first sleep restriction period (fourth, sixth and eighth night), the first recovery period (ninth night), the second sleep restriction period (eleventh and thirteenth night), and the second recovery period (fourteenth night).

  2. Change in N1 sleep duration at night assessed with polysomnography from baseline nights to the first and second cycles of sleep restriction and recovery

    Time frame: Nocturnal sleep on nights 1 & 3 (baseline), 4, 6 & 8 (first sleep restriction period), 9 (first recovery period), 11 & 13 (second sleep restriction period), & 14 (second recovery period)

    Duration of nocturnal N1 sleep was determined to establish baseline sleep characteristics (first and third nights) and changes in the first sleep restriction period (fourth, sixth and eighth night), the first recovery period (ninth night), the second sleep restriction period (eleventh and thirteenth night), and the second recovery period (fourteenth night).

  3. Change in N2 sleep duration at night assessed with polysomnography from baseline nights to the first and second cycles of sleep restriction and recovery

    Time frame: Nocturnal sleep on nights 1 & 3 (baseline), 4, 6 & 8 (first sleep restriction period), 9 (first recovery period), 11 & 13 (second sleep restriction period), & 14 (second recovery period)

    Duration of nocturnal N2 sleep was determined to establish baseline sleep characteristics (first and third nights) and changes in the first sleep restriction period (fourth, sixth and eighth night), the first recovery period (ninth night), the second sleep restriction period (eleventh and thirteenth night), and the second recovery period (fourteenth night).

  4. Change in N3 sleep duration at night assessed with polysomnography from baseline nights to the first and second cycles of sleep restriction and recovery

    Time frame: Nocturnal sleep on nights 1 & 3 (baseline), 4, 6 & 8 (first sleep restriction period), 9 (first recovery period), 11 & 13 (second sleep restriction period), & 14 (second recovery period)

    Duration of nocturnal N3 sleep was determined to establish baseline sleep characteristics (first and third nights) and changes in the first sleep restriction period (fourth, sixth and eighth night), the first recovery period (ninth night), the second sleep restriction period (eleventh and thirteenth night), and the second recovery period (fourteenth night).

  5. Change in REM sleep duration at night assessed with polysomnography from baseline nights to the first and second cycles of sleep restriction and recovery

    Time frame: Nocturnal sleep on nights 1 & 3 (baseline), 4, 6 & 8 (first sleep restriction period), 9 (first recovery period), 11 & 13 (second sleep restriction period), & 14 (second recovery period)

    Duration of nocturnal REM sleep was determined to establish baseline sleep characteristics (first and third nights) and changes in the first sleep restriction period (fourth, sixth and eighth night), the first recovery period (ninth night), the second sleep restriction period (eleventh and thirteenth night), and the second recovery period (fourteenth night).

  6. Change in total sleep duration during daytime naps assessed with polysomnography from the first to the second sleep restriction period

    Time frame: Afternoon naps on days 4, 6 & 8 (first sleep restriction period), 11 & 13 (second sleep restriction period)

    Total duration of sleep during the selected nap episodes was determined to track changes in this parameter from the first sleep restriction period (fourth, sixth and eighth day) to the second sleep restriction period (eleventh and thirteenth day).

  7. Change in N1 sleep duration during daytime naps assessed with polysomnography from the first to the second sleep restriction period

    Time frame: Afternoon naps on days 4, 6 & 8 (first sleep restriction period), 11 & 13 (second sleep restriction period)

    Duration of N1 sleep during the selected nap episodes was determined to track changes in this parameter from the first sleep restriction period (fourth, sixth and eighth day) to the second sleep restriction period (eleventh and thirteenth day).

  8. Change in N2 sleep duration during daytime naps assessed with polysomnography from the first to the second sleep restriction period

    Time frame: Afternoon naps on days 4, 6 & 8 (first sleep restriction period), 11 & 13 (second sleep restriction period)

    Duration of N2 sleep during the selected nap episodes was determined to track changes in this parameter from the first sleep restriction period (fourth, sixth and eighth day) to the second sleep restriction period (eleventh and thirteenth day).

  9. Change in N3 sleep duration during daytime naps assessed with polysomnography from the first to the second sleep restriction period

    Time frame: Afternoon naps on days 4, 6 & 8 (first sleep restriction period), 11 & 13 (second sleep restriction period)

    Duration of N3 sleep during the selected nap episodes was determined to track changes in this parameter from the first sleep restriction period (fourth, sixth and eighth day) to the second sleep restriction period (eleventh and thirteenth day).

  10. Change in REM sleep duration during daytime naps assessed with polysomnography from the first to the second sleep restriction period

    Time frame: Afternoon naps on days 4, 6 & 8 (first sleep restriction period), 11 & 13 (second sleep restriction period)

    Duration of REM sleep during the selected nap episodes was determined to track changes in this parameter from the first sleep restriction period (fourth, sixth and eighth day) to the second sleep restriction period (eleventh and thirteenth day).

Sponsors and collaborators

Lead sponsor

Duke-NUS Graduate Medical School

Other

Collaborators

  • National Medical Research Council (NMRC), Singapore

Registry information

Official study title

Effectiveness of a Daytime Nap on Alleviating Cognitive Impairment Due to Short Sleep in Adolescents

Important dates

Study start
2015
Primary completion
2015
Study completion
2015
First posted
Jul 20, 2016
Registry last updated
Jul 20, 2016

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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