Clinical trial NCT04044885: Investigating Preferred Nap Schedules for Adolescents
Official title: Investigating the Preferred Nap Schedule for Adolescents With Adequate Sleep
Study type: INTERVENTIONAL
Overall status: COMPLETED
Phase: NA
Conditions: Sleep
Keywords: Nap
Recovery sleep
Cognitive functions
Neurobehavioural functions
Mood
Subjective sleepiness
Lead sponsor: Duke-NUS Graduate Medical School
Sponsor class: OTHER
Collaborators: name: National Medical Research Council (NMRC), Singapore
First posted: 2019-08-05
Enrollment: 54
Sex: ALL
Minimum age (years): 15
Maximum age (years): 19
Standard ages: CHILD
ADULT
Accepts healthy volunteers: yes
Allocation: RANDOMIZED
Intervention model: PARALLEL
Primary purpose: BASIC_SCIENCE

Brief summary: The aim of this study is to examine the neurobehavioural responses to two successive cycles of sleep manipulation nights and recovery nights in adolescents, and to determine the benefits of napping on cognitive performance, alertness and mood. Using a split-sleep design, 60 participants, aged 15 to 19 years old, are divided into a nap and a no-nap group. Both groups undergo two cycles of sleep manipulation nights and recovery nights over a period of 15 days. The no-nap group receives an 8-hour sleep opportunity on sleep restriction nights, with no daytime nap opportunity. The nap group receives a 6.5-hour sleep opportunity on sleep restriction nights, and has a 1.5-hour nap opportunity the following afternoon.

Detailed description: The present study investigates whether a continuous stretch of night time sleep (8 hours) will lead to better neurobehavioural outcomes relative to nocturnal sleep restriction (6.5 hours) and daytime nap (1.5 hours) of the same total duration. The 15-day protocol is conducted in a dormitory on 60 high school students, aged 15 to 19 years old. Participants are assigned to a nap or no-nap group. Both groups start with two 9-hour adaptation and baseline nights, followed by two successive cycles of sleep restriction (6.5-h time in bed (TIB); 00:15-06:45 or 8-h TIB; 23:30-07:30) and recovery (9-h TIB; 23:00-08:00). Following each sleep-restricted night, the nap group receives a 1.5-h nap opportunity, while participants in the no-nap group watch a documentary. Throughout the protocol, sleep-wake patterns are assessed with actigraphy and polysomnography. Sleepiness levels, mood, vigilance, working memory / executive functions, and speed of processing are assessed 3 times daily (10:00, 16:15, and 20:00).

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

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

Eligibility criteria: 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

Primary outcomes:
measure: 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
timeFrame: 3 times daily (10:00, 16:15, and 20:00) for 15 days
measure: 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
timeFrame: 3 times daily (10:00, 16:15, and 20:00) for 15 days
measure: 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
timeFrame: 3 times daily (10:00, 16:15, and 20:00) for 15 days
measure: 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
timeFrame: 3 times daily (10:00, 16:15, and 20:00) for 15 days
measure: 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
timeFrame: 3 times daily (10:00, 16:15, and 20:00) for 15 days
measure: 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
timeFrame: 3 times daily (10:00, 16:15, and 20:00) for 15 days
measure: 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
timeFrame: 3 times daily (10:00, 16:15, and 20:00) for 15 days
measure: 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
timeFrame: 3 times daily (10:00, 16:15, and 20:00) for 15 days
measure: 11.Change in memory performance in picture-word association task over sleep restriction nights and recovery night
timeFrame: 12 times (morning and evening): after sleep restriction night 1, 2, 3, 4 and 5 (sleep restriction period 1) and after recovery night 2 (recovery period 1)
measure: 14.Effect of sleep versus wake during delay on memory for rewarded pictures, where the pictures will be encoded either before a 12-hr interval including a night of sleep or a day of wakefulness
timeFrame: Single session during the 15-day protocol, after baseline night 1 or before sleep restriction night 1 (first sleep restriction period)
measure: 15.Effect of sleep restriction on learning of novel material (about different animal species) across separate sessions
timeFrame: Single session during the 15-day protocol, after recovery night 2 (first recovery period)
measure: 16.Effect of sleep restriction on memory of spatial locations
timeFrame: Single session during the 15-day protocol, after sleep restriction night 3 (first sleep restriction period)
measure: 18.Effect of sleep restriction on picture encoding
timeFrame: Single session during the 15-day protocol, after recovery night 2 (second recovery period)
measure: 19.Effect of sleep restriction on effort/temporal discounting
timeFrame: Three sessions during the 15-day protocol (after baseline night 1, after sleep restriction night 5 (first sleep restriction period) and after recovery night 2 (first recovery period))
Secondary outcomes:
measure: Change in total sleep duration at night assessed with polysomnography from baseline nights to the first and second cycles of sleep restriction and recovery
timeFrame: Nocturnal sleep on nights 1 & 2 (baseline), 3, 5 & 7 (first sleep restriction period), 8 (first recovery period), 10 & 12 (second sleep restriction period), & 13 (second recovery period)
measure: Change in N1 sleep duration at night assessed with polysomnography from baseline nights to the first and second cycles of sleep restriction and recovery
timeFrame: Nocturnal sleep on nights 1 & 2 (baseline), 3, 5 & 7 (first sleep restriction period), 8 (first recovery period), 10 & 12 (second sleep restriction period), & 13 (second recovery period)
measure: Change in N2 sleep duration at night assessed with polysomnography from baseline nights to the first and second cycles of sleep restriction and recovery
timeFrame: Nocturnal sleep on nights 1 & 2 (baseline), 3, 5 & 7 (first sleep restriction period), 8 (first recovery period), 10 & 12 (second sleep restriction period), & 13 (second recovery period)
measure: Change in N3 sleep duration at night assessed with polysomnography from baseline nights to the first and second cycles of sleep restriction and recovery
timeFrame: Nocturnal sleep on nights 1 & 2 (baseline), 3, 5 & 7 (first sleep restriction period), 8 (first recovery period), 10 & 12 (second sleep restriction period), & 13 (second recovery period)
measure: Change in Rapid Eye Movement (REM) sleep duration at night assessed with polysomnography from baseline nights to the first and second cycles of sleep restriction and recovery
timeFrame: Nocturnal sleep on nights 1 & 2 (baseline), 3, 5 & 7 (first sleep restriction period), 8 (first recovery period), 10 & 12 (second sleep restriction period), & 13 (second recovery period)
measure: Change in total sleep duration during daytime naps assessed with polysomnography from the first to the second sleep restriction period
timeFrame: Afternoon naps on days 4, 6 & 8 (first sleep restriction period), 11 & 13 (second sleep restriction period
measure: Change in N1 sleep duration during daytime naps assessed with polysomnography from the first to the second sleep restriction period
timeFrame: Afternoon naps on days 4, 6 & 8 (first sleep restriction period), 11 & 13 (second sleep restriction period
measure: Change in N2 sleep duration during daytime naps assessed with polysomnography from the first to the second sleep restriction period
timeFrame: Afternoon naps on days 4, 6 & 8 (first sleep restriction period), 11 & 13 (second sleep restriction period
measure: Change in N3 sleep duration during daytime naps assessed with polysomnography from the first to the second sleep restriction period
timeFrame: Afternoon naps on days 4, 6 & 8 (first sleep restriction period), 11 & 13 (second sleep restriction period
measure: Change in REM sleep duration during daytime naps assessed with polysomnography from the first to the second sleep restriction period
timeFrame: Afternoon naps on days 4, 6 & 8 (first sleep restriction period), 11 & 13 (second sleep restriction period
Other outcomes:
Locations:
city: Singapore
country: Singapore
facility: Duke-NUS Medical School
Study officials:
affiliation: Duke-NUS Graduate Medical School
name: Michael WL Chee, MBBS
role: PRINCIPAL_INVESTIGATOR
References:
citation: Aghayan Golkashani H, Leong RLF, Ghorbani S, Ong JL, Fernandez G, Chee MWL. A sleep schedule incorporating naps benefits the transformation of hierarchical knowledge. Sleep. 2022 Apr 11;45(4):zsac025. doi: 10.1093/sleep/zsac025.
citation: Lo JC, Koa TB, Ong JL, Gooley JJ, Chee MWL. Staying vigilant during recurrent sleep restriction: dose-response effects of time-in-bed and benefits of daytime napping. Sleep. 2022 Apr 11;45(4):zsac023. doi: 10.1093/sleep/zsac023.
citation: Leong RLF, Yu N, Ong JL, Ng ASC, Jamaluddin SA, Cousins JN, Chee NIYN, Chee MWL. Memory performance following napping in habitual and non-habitual nappers. Sleep. 2021 Jun 11;44(6):zsaa277. doi: 10.1093/sleep/zsaa277.
citation: Lo JC, Leong RLF, Ng ASC, Jamaluddin SA, Ong JL, Ghorbani S, Lau T, Chee NIYN, Gooley JJ, Chee MWL. Cognitive effects of split and continuous sleep schedules in adolescents differ according to total sleep opportunity. Sleep. 2020 Dec 14;43(12):zsaa129. doi: 10.1093/sleep/zsaa129.