Effects of Morningness on Night Split Shift Performance

Shift-work Disorder Clinical Trial

Official title:

Effects of Morningness on Night Split Shift Performance

Clinical Trial Details — Status: Active, not recruiting

Administrative data

• NCT number: NCT06440434
• Other study ID #: M3447
• Status: Active, not recruiting
• Phase: N/A
• Start date: April 19, 2024
• Est. completion date: December 31, 2024

Study information

• Verified date: June 2024
• Source: University of Bergen
• Contact: n/a
• Is FDA regulated: No
• Study type: Interventional

Clinical Trial 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

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).

Recruitment information / eligibility

• Status: Active, not recruiting
• Enrollment: 30
• Est. completion date: December 31, 2024
• Est. primary completion date: June 20, 2024
• Accepts healthy volunteers: Accepts Healthy Volunteers
• Gender: All
• Age group: 18 Years to 40 Years

Eligibility

Inclusion Criteria:

• 18-40 years old

• no incorrectable vision problems

Exclusion Criteria:

• regular use of sleep medication

Related Conditions & MeSH terms

• Shift-work Disorder

Intervention

Behavioral:
• Time of night shift
Early vs. late night split night shift

Locations

Country	Name	City	State
Norway	University of Bergen	Bergen

Sponsors (1)

Lead Sponsor	Collaborator
University of Bergen

Country where clinical trial is conducted

Norway, 

Outcome

Type	Measure	Description	Time frame	Safety issue
Primary	Total sleep time	Total sleep (sleep diary and radar). Higher values indicates more sleep	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)
Primary	Psychomotor Vigilance Test (PVT)	Reaction time (mean 1/RT) and number of lapses (RTs=500 ms). For mean 1/RT higher values are associated with best performance, on lapses higher values are associated with worst performance	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)
Primary	Karolinska Sleepiness Scale (KSS)	Assessment of state sleepiness, range 1-9 (higher scores indicate worse state)	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	Sleep efficiency (percentage of time in bed one sleeps)	Sleep efficiency (diary and radar). Range from 0-100%. Higher scores indicate best state	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)
Secondary	Positive and Negative Affect Schedule (PANAS)	Assessment of mood/affect. Range 10-50. On positive mood subscale higher scores indicate best state, on negative mood state, higher scores indicate worst state	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	Self-rated performance	Self-rated performance on cognitive tests. Range 1-10. Higher scores indicate best performance rating	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	Digital Symbol Substitution Test	Test where one match symbols to numbers as fast as possible. Range 0-100. Higher scores indicate best performance	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	Working Memory Scanning Test (probed recall)	Test presenting list of words. Then words are presented and subjects decide if word was present or not in list presented. The accuracy and RTs for positive trials (where probe was present in list) will be used as dependent variables. Higher accuracy and lower reaction time are associated with best performance	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	Reversal Learning Test	Test measuring the ability to differentiating between "go-stimuli" and "no-go stimuli" before and after reversal of go and no-go stimuli. Discriminability (hit rate/false alarm rate) and response bias before and after reversal are recorded. Higher discriminability indicates better performance, higher response bias indicate worse performance	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	Visual Search Test	Multiple objects are presented, and from among them a target is identified. The task of the subject is finding the target. Outcomes are reaction time (RT) and accuracy. Lower reaction times and higher accuracy are associated with best performance	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)