ABSTRACT TITLE: The effect of sleep restriction on face-name association learning
PRESENTING AUTHOR: Delli Colli, Luca2,3
CO-AUTHORS: Mograss, Melodee1,2,3,4; Zvionow, Tehila2,3; Dimopoulos, Chris1,3; Vacirca, Felicia1,3; Haiun, Jonathan1,3; Frimpong, Emmanuel2,3 and Thanh Dang-Vu, Thien1,2,3,4
AFFILIATIONS: 1. Dept of Psychology, Concordia University, Montreal, QC, CA; 2. Dept of Health, Kinesiology & Applied Physiology, Concordia University, Montreal, QC, CA; 3. Concordia University PERFORM Centre, Montreal, QC, CA; 4. Centre de Recherche de l’Institut Universitaire de Gériatrie de Montréal
DESCRIPTION: Background: Sleep loss is common in our modern society due to social, work and family commitments. Total sleep deprivation has shown to cause a wide variety of negative effects. There are a limited number of studies on individuals who sleep slightly less than the average 8hr of sleep/night on memory.
Objective: We aimed to assess the effects of sleep restriction on episodic memory using a face-name association learning task.
Methods: Participants completed on-line screening questionnaires for medical, psychological, sleep history, and physical activity status. A sleep diary was completed 4 days prior to and during the experimental night (Day 5) to determine consistency of sleep schedules. Included participants were randomized into two groups: Restricted sleep opportunity (s5, ~5-6 h/night) and Average sleep opportunity (s8, ~8-9 h/night). On Day 5, a three-part face-name recall task was performed. This task involved an encoding phase and immediate recall phase, separated by a 5-minute break, and a restricted or average nighttime sleep opportunity, inserted between immediate and delayed recall phases. All procedures were conducted remotely. Data for immediate and delayed retrievals were generated by the task, while differences between immediate and delayed retrieval performance metrics (accuracy, reaction time - RT) were also computed within each group. Normality was assessed using Kolmogorov-Smirnov and Shapiro Wilk tests. Participant demographics, screening questionnaire scores, and sleep diary entries were summarized as means and standard deviations. Groups were compared with unpaired t-test and Mann-Whitney U test.
Results: A total of 41 healthy, average sleepers (25.2±4.1 yrs), were included in this online pilot study. A significant difference in the experimental night (Day 5) was found between s5 vs. s8 for TST [(mean±SD, 5.35±0.3 vs. 8.07±0.3) hr, p < 0.001] and SOL [(8.2±6.0 vs 14.6±7.2) min, p<0.05] respectively. Recall performance showed no difference across the two groups for immediate retrieval of number of correct responses (accuracy) and reaction time (RT), delayed retrieval RT, and the mean difference between delayed and immediate retrieval accuracy, p’s >0.05. During the delayed retrieval, there was a significant difference between s8 vs. s5 group in accuracy (72.00±9.27 vs. 67.15±9.65, Mann-Whitney U = 276.0, p<0.05) and in the Karolinska Sleepiness score, KSS (4.15±1.66 vs 6.30±1.63, Mann-Whitney U = 72.50, p= 0.004).
Conclusion: Sleep restriction appears to have detrimental effect on episodic memory recall. Seeing as this study was conducted online, future studies should aim to confirm these findings in a well-controlled lab environment, as well as determining if motivational or other factors influence sleep loss in individuals who are partially sleep deprived.