Sleep deprivation and its effects on communication during individual and collaborative tasks

Sleep loss has been shown to cause impairments in a number of aspects central for successful communication, ranging from poorer linguistic comprehension to alterations in speech prosody. However, the effect of sleep loss on actual communication is unknown. This study investigated how a night of sleep deprivation affected performance during multiple tasks designed to test verbal communication. Healthy participants (N = 183) spent 8–9 hours per night in bed for three nights and were then randomised to either one night of total sleep deprivation or a fourth night with 8–9 hours in bed. The following day, participants completed two tasks together with another participant: a model-building task and a word-description task. Differences in performance of these tasks were assessed alongside speaking duration, speaking volume, and speaking volume consistency. Additionally, participants individually completed a verbal fluency assessment. Performance on the model-building task was worse if the model-builder was sleep deprived, whereas sleep deprivation in the instruction-giver predicted an improvement. Word-description, verbal fluency, speech duration, speaking volume, and speaking volume consistency were not affected. The results suggest that sleep deprivation leads to changes in communicative performance during instructive tasks, while simpler word-description tasks appear resilient.

Have you had any of the following problems during the last 6 months? (alternatives: never or seldom, up to three times per month, one-three times per week, four times per week or more): Exclude: 'four times per week or more' How much sleep do you think that you need per day? Exclude: below 7 hours or above 9 hours Do you use any medicine or supplement to sleep better? (alternatives: Yes regularly, yes periodically, no) Exclude: 'yes regularly' or 'yes periodically' HEALTH Have you been in contact with a doctor over any of the following (alternatives: no, yes currently, yes during the last year, yes more than a year ago): • Pain in the chest or back • Disturbed sleep • Depression • Other psychiatric problem (e.g. anxiety, worry, sadness, etc.) • Heart attack and / or high blood pressure • Diabetes • Other disease: [specify] Exclude: 'yes currently' or 'yes during the last year' Do you take any medicine regularly? Follow-up: If yes, research assistant investigates further. Contraceptive pill, weak pain medication is okay. Decision on a case-by-case basis.
What is your tobacco usage? (alternatives: do not smoke or use snus, previously smoker/snus-user (stopped more than 3 months ago), previously smoker/snus-user (stopped less than 3 months ago), current smoker or snus-user, smoke/use snus sometimes Exclude: 'previously smoker/snus-user (stopped for less than 3 months ago)' or 'current smoker/snus-user' Follow-up: 'Smoke/use snus sometimes' [check that the participant can abstain for more than a day].
How often do you drink alcohol? (alternatives: never, once a month or less, 2-4 times a month, 2-3 times a week, 4 times a week or more) Follow-up: '2-3 times a week' or '4 times a week or more' [check what sort of strength the alcohol is. If weak beer (< 3.5%) okay, if strong spirit exclude] How much coffee do you drink per day? (alternatives: none, 1-2 cups, 3-4 cups, 5-6 cups, 7 or more cups) Exclude: '7 or more cups' Follow-up: '3-4 cups', or '5-6 cups' [check whether they can abstain from caffeine without experiencing withdrawal-effects] How often do you use drugs other than coffee, alcohol, or tobacco? (alternatives: never, once a month or less, 2-4 times per month, 2-3 times per week, 4 times per week or more) Exclude: 2-4 times per month, 2-3 times per week, 4 times per week or more OTHER QUESTIONS Have you worked a night-shift during the last month? (alternatives: yes, no) Follow-up: yes [must be more than 3 weeks before the testing day]

How well do the following statements characterise you? (alternatives: 0 -characterises very well, 0 -characterises quite well, 1 -characterises quite poorly, 2-doesn't characterise me at all) [summed score for the following items]
• It is easy for me to "read between the lines" when someone talks to me • I can tell if a person listening to me is getting bored • When I read a story it is difficult for me to understand the intentions of the characters* • I find it easy to work out what someone is thinking or feeling just by looking at their face* • I find it difficult to work out the intentions of other people *Reverse scored Exclude: any sum score of 4 or more.
Have you flown abroad in the last month? (alternatives: yes, no) Follow-up: yes [exclude if it was less than three weeks since this trip or the location was less than three time-zones away] Johns, M. W. A new method for measuring daytime sleepiness: the Epworth sleepiness scale. Sleep, 1991, 14: 540-545 Chung, F., Abdullah, H.R., Liao, P. STOP-bang questionnaire a practical approach to screen for obstructive sleep apnea. Chest, 2016, 149: 631-638. mean effect = 0, sigma = 2.25, limited between -9 and 9. Time-taken priors: mean effect = 0, sigma = 150, limited between -600 and 600. Efficiency model priors: mean effect = 0, sigma =0.5, limited between -2 and 2. A cumulative distribution was used for the score response outcome, while a Gaussian distribution was used for time and efficiency outcomes. Note. Sleep deprivation N = 89; Control N = 91. Mu = posterior distribution mean; HDI = 95% Highest Density Interval; Sigma = posterior distribution residual standard deviation. Priors were set on the effect; since there was no maximum possible effect, sigma was set as a quarter of maximum observed round score (mean = 0, sigma = 1.5). The response distribution was set to cumulative since model fit comparisons revealed that this was the best fit for the data.