Clinical trial NCT06440434: Effects of Morningness on Night Split Shift Performance
Official title: Effects of Morningness on Night Split Shift Performance
Study type: INTERVENTIONAL
Overall status: ACTIVE_NOT_RECRUITING
Phase: NA
Conditions: Shift-work Disorder
Lead sponsor: University of Bergen
Sponsor class: OTHER
First posted: 2024-06-03
Enrollment: 30
Sex: ALL
Minimum age (years): 18
Maximum age (years): 40
Standard ages: ADULT
Accepts healthy volunteers: yes
Allocation: RANDOMIZED
Intervention model: CROSSOVER
Intervention model description: A 2 (midnight-4am vs.4am-8am) within factor x 2 (below vs. above median on morningness) between factor experimental design
Primary purpose: BASIC_SCIENCE

Brief summary: The goal is to investigate if the morningness-eveningness dimension mediates sleep and function on spilt night shifts (midnight-4am and 4am-8am).

Does those with high score of morningness function relatively better on the last compared to the first split shift?

Participants will:

Record their sleep from 2 days prior to 2 days following the split shift During the shifts complete questionnaires assessing mood, sleepiness and perceived performance as well as complete cognitive tests: Psychomotor vigilance test, digit symbol substitution test, working memory scanning test, reversal learning test, and visual search test

Detailed description: A sample of 28 students will be recruited and exposed to two conditions in a randomized, controlled, crossover study. They will be assessed with subjective (sleep diary) and objective sleep measures (sleep radar) for 2 days before the night shift, during the night shift and 2 days following the night shift. The simulated night shifts will last from midnight to 8am and will be divided into two halves (midnight-4am and 4am-8am), denoted as split-shift, and for each participant separated by at least 1 week. Based on the Horne-Östberg Morningness-Eveningness Questionnaire (median spilt) two groups are created, from which participants will be randomized to the two orders of the spilt-shift.

Each hour on each shift the participants will complete: Positive and Negative Affect Schedule (PANAS), Karolinska Sleepiness Scale, perceived performance and the following cognitive tests: Psychomotor vigilance test, Digit symbol substitution test, Working memory scanning test, Reversal learning test, and Visual search test.

Data will be analyzed with linear mixed models with three fixed factors: Group (low vs. high morningness), shift (midnight-4am vs. 4am-8am), and hour and one random factor (participant).

Eligibility criteria: Inclusion Criteria:

* 18-40 years old
* no incorrectable vision problems

Exclusion Criteria:

\* regular use of sleep medication

Primary outcomes:
measure: Total sleep time
timeFrame: Total sleep time between 6pm day before shift start to 6pm the day the shift end for both early night shift (midnight-04am) and late night shift (04am-08am)
measure: Psychomotor Vigilance Test (PVT)
timeFrame: Hourly during shifts (0:15am, 1:15am, 2:15am and 3:15am on early night shift; 4:15am, 5:15am, 6:15am and 7:15 am on late night shift)
measure: Karolinska Sleepiness Scale (KSS)
timeFrame: Hourly during shifts (0:15am, 1:15am, 2:15am and 3:15am on early night shift; 4:15am, 5:15am, 6:15am and 7:15 am on late night shift)
Secondary outcomes:
measure: Sleep efficiency (percentage of time in bed one sleeps)
timeFrame: Between 6pm day before shift start to 6pm the day the shift end for both early night shift (midnight-04am) and late night shift (04am-08am)
measure: Positive and Negative Affect Schedule (PANAS)
timeFrame: Hourly during shifts (0:15am, 1:15am, 2:15am and 3:15am on early night shift; 4:15am, 5:15am, 6:15am and 7:15 am on late night shift)
measure: Self-rated performance
timeFrame: Hourly during shifts (0:15am, 1:15am, 2:15am and 3:15am on early night shift; 4:15am, 5:15am, 6:15am and 7:15 am on late night shift)
measure: Digital Symbol Substitution Test
timeFrame: Hourly during shifts (0:15am, 1:15am, 2:15am and 3:15am on early night shift; 4:15am, 5:15am, 6:15am and 7:15 am on late night shift)
measure: Working Memory Scanning Test (probed recall)
timeFrame: Hourly during shifts (0:15am, 1:15am, 2:15am and 3:15am on early night shift; 4:15am, 5:15am, 6:15am and 7:15 am on late night shift)
measure: Reversal Learning Test
timeFrame: Hourly during shifts (0:15am, 1:15am, 2:15am and 3:15am on early night shift; 4:15am, 5:15am, 6:15am and 7:15 am on late night shift)
measure: Visual Search Test
timeFrame: Hourly during shifts (0:15am, 1:15am, 2:15am and 3:15am on early night shift; 4:15am, 5:15am, 6:15am and 7:15 am on late night shift)
Other outcomes:
Locations:
city: Bergen
country: Norway
facility: University of Bergen
Study officials:
References: