Effect of chronic sleep restriction on sleepiness and working memory in adolescents and young adults

Effects of sleep reduction on the phonological and visuospatial components of working memory

Sleep reduction impairs the performance of many tasks, so it may affect a basic cognitive process, such as working memory, crucial for the execution of a broad range of activities. Working memory has two storage components: a phonological and a visuospatial component. The objective of this study was to analyze the effects of sleep reduction for 5 days on the storage components of working memory. Thirteen undergraduate students (18.77±2.20 years of age), 5 men and 8 women, responded two N-Back tasks (auditory and visual), with three sections each (0-Back, 1-Back, and 2-Back). These tasks were performed at 13:00 h under the following conditions: before sleep reduction (control; C); on the first (SR1), fourth (SR4), and fifth (SR5) days of sleep reduction (4 h of sleep per night); and one day after they slept freely (recovery, R). Sleep reduction produced a decrement in accuracy on the auditory 2-Back section the fifth day of sleep reduction (C=87.86±13.35%; SR5=74.76±16.37%; F=14.57, p<0.01). In the visual 2-Back section accuracy decreased (C=88.10±9.95%; SR1=82.45±11.57%; SR5=77.76±14.14%; F=10.80, p<0.05), and reaction time increased (C=810.02±173.96 ms; SR1=913.51±172.25 ms; SR5=874.78±172.27 ms; F=10.80, p<0.05) on the first and fifth day of sleep reduction. In conclusion, five days of sleep reduction produces a decrease in the phonological and visuospatial storage components of working memory, which may interfere with processing verbal information and solving problems that require spatial analysis.

Self-reported memory problems in adult-onset cancer survivors: effects of cardiovascular disease and insomnia

BACKGROUND

Cancer and its treatments can deleteriously affect memory. Cardiac function and insomnia can exacerbate memory problems.

OBJECTIVE

To examine the relationships among cardiovascular disease, insomnia, and self-reported memory problems (SRMP) in adult-onset cancer survivors.

METHODS

We included data from participants (41-64 year-old) of the 2007-2008 National Health and Nutrition Examination Survey, a nationally representative probability sample of the civilian, non-institutionalized population of the US. We excluded participants with brain cancer/stroke history since these conditions are expected to cause cognitive problems. Using binary logistic regression, we determined the prevalence of SRMP relative to cardiac problems and insomnia by weighting our results proportionally. We adjusted for predictors of memory problems: age, sex, race, education and general health.

RESULTS

The sample included 2289 adults (49% females), 9% with a cancer history. The results pertain only to cancer survivors. Those with insomnia were 16 times as likely to have SRMP. Only insomnia symptoms (OR, 15.74; 95% CI, 1.73-143.30; p < 0.01) significantly predicted SRMP, uniquely explaining 12% of the variance. Insomnia accounted for 18.8% of the association between cardiac issues and SRMP, demonstrating mediation (Sobel p < 0.05). The large CI is a consequence of analyzing a sub-group of a subpopulation. Among participants without a cancer history, cardiovascular disease and insomnia were not associated with SRMP (p > 0.05).

LIMITATIONS

We could not determine severity and time-related changes in SRMP.

CONCLUSION

Likelihood of SRMP was higher in cancer survivors with a history of cardiovascular disease and insomnia symptoms. Future studies are needed to delineate the cardiac-insomnia-memory interrelationships.

Poor sleep and lower working memory in grade 1 children: cross-sectional, population-based study

OBJECTIVE

Poor sleep and working memory difficulties are both associated with learning difficulties, but it is not known whether they are linked with each other in childhood. We aimed to determine, in a population-based sample of grade 1 children, whether poor sleep is associated with reduced working memory capacity.

METHODS

Cross-sectional population-based study. All grade 1 children in 44 elementary schools in metropolitan Melbourne, Australia; 1749 children were included (participation rate 65%, mean age 6.9 years). Parents completed a written questionnaire at home, after which researchers administered one-on-one child computerized assessments at school. Predictor measures were parent-reported 1) perceptions of poor sleep, 2) regularity of bedtime, 3) sleep duration, and 4) sleep onset latency. Outcome measures were backward digit recall (verbal working memory) and Mister X (visuospatial working memory) subtests of the Automated Working Memory Assessment (AWMA). Associations were examined using linear regression, adjusted for duration of schooling, gender, age, and social status.

RESULTS

Increasing poor sleep (P = .03), less regularity of bedtime (P < .001), and shorter sleep duration (P = .03) were all associated with poorer verbal working memory, with effect sizes ranging from 0.3 to 1.2. Poor sleep was not associated with visuospatial working memory.

CONCLUSIONS

At a population level, poor sleep in early school-age children is associated with poorer verbal working memory, an important predictor of academic difficulties.

The effect of one night's sleep deprivation on adolescent neurobehavioral performance

STUDY OBJECTIVES

To investigate the effects of one night's sleep deprivation on neurobehavioral functioning in adolescents.

DESIGN

Participants completed a neurobehavioral test battery measuring sustained attention, reaction speed, cognitive processing speed, sleepiness, and fatigue every 2 h during wakefulness. Baseline performance (defined as those test bouts between 09:00 and 19:00 on days 2 and 3, following two 10-h sleep opportunities) were compared to performance at the same clock time the day following total sleep deprivation.

SETTING

The sleep laboratory at the Centre for Sleep Research.

PARTICIPANTS

Twelve healthy adolescents (6 male), aged 14-18 years (mean = 16.17, standard deviation = 0.83).

MEASUREMENTS AND RESULTS

Sustained attention, reaction speed, cognitive processing speed, and subjective sleepiness were all significantly worse following one night without sleep than following 10-h sleep opportunities (all main effects of day, P < 0.05). Sleep deprivation led to increased variability on objective performance measures. There were between-subjects differences in response to sleep loss that were task-specific, suggesting that adolescents may not only vary in terms of the degree to which they are affected by sleep loss but also the domains in which they are affected.

CONCLUSIONS

These findings suggest that one night of total sleep deprivation has significant deleterious effects upon neurobehavioral performance and subjective sleepiness. These factors impair daytime functioning in adolescents, leaving them at greater risk of poor academic and social functioning and accidents and injuries.

Single night video-game use leads to sleep loss and attention deficits in older adolescents

The present study investigated adolescent video-game use prior to bedtime and subsequent sleep, working memory and sustained attention performance. Participants were 21 healthy, good-sleeping adolescents (16 male) aged between 15 and 20 years (M = 17.6 years, SD = 1.8). Time spent video-gaming and subsequent sleep was measured across one night in the sleep laboratory. There were significant correlations between time spent video-gaming and sleep and between video-gaming and sustained attention, but not working memory. Sleep duration, in turn, had a significant negative association with sustained attention performance. Mediation analyses revealed that the relationship between video-gaming and sustained attention was fully mediated by sleep duration. These results indicate that video-gaming affected the ability to sustain attention only in as much as it affected sleep. In order to minimise negative consequences of video-game playing, video-games should be used in moderation, avoiding use close to the sleep period, to obviate detriments to sleep and performance.

Influence of chronic moderate sleep restriction and exercise training on anxiety, spatial memory, and associated neurobiological measures in mice

Sleep deprivation can have deleterious effects on cognitive function and mental health. Moderate exercise training has myriad beneficial effects on cognition and mental health. However, physiological and behavioral effects of chronic moderate sleep restriction and its interaction with common activities, such as moderate exercise training, have received little investigation. The aims of this study were to examine the effects of chronic moderate sleep restriction and moderate exercise training on anxiety-related behavior, spatial memory, and neurobiological correlates in mice. Male mice were randomized to one of four 11-week treatments in a 2 [sleep restriction (∼4h loss/day) vs. ad libitum sleep] × 2 [exercise (1h/day/6 d/wk) vs. sedentary activity] experimental design. Anxiety-related behavior was assessed with the elevated-plus maze, and spatial learning and memory were assessed with the Morris water maze. Chronic moderate sleep restriction did not alter anxiety-related behavior, but exercise training significantly attenuated anxiety-related behavior. Spatial learning and recall, hippocampal cell activity (i.e., number of c-Fos positive cells), and brain derived neurotrophic factor were significantly lower after chronic moderate sleep restriction, but higher after exercise training. Further, the benefit of exercise training for some memory variables was evident under normal sleep, but not chronic moderate sleep restriction conditions. These data indicate clear detrimental effects of chronic moderate sleep restriction on spatial memory and that the benefits of exercise training were impaired after chronic moderate sleep restriction.

Important steps to improve translation from medical research to health policy

Translational medicine entails not only “from-bench-to-bedside” but also preventive medicine. The present article proposes a conceptual framework of translational research from scientific research to health care policy and public health policy. We highlight the importance of translational medicine to bridge between research and policy and share our experience of translating medical research to public health policy in China as well as obstacles and challenges we are facing in the translation process.

Sleep in children with autism spectrum disorder

Children with autism spectrum disorder demonstrate an increased prevalence of difficulties with sleep initiation and maintenance. The consequences may include alterations in daytime behavior, memory, and learning in patients, and significant stress in caretakers. The dysregulation of melatonin synthesis, sensitization to environmental stimuli, behavioral insomnia syndromes, delayed sleep phase syndrome, rapid eye movement sleep behavior disorder, and comorbid anxiety, depression, and epilepsy comprise common etiologic factors. The clinical assessment of sleep problems in this population and a management algorithm are presented.

Repeated sleep restriction in adolescent rats altered sleep patterns and impaired spatial learning/memory ability

STUDY OBJECTIVES

To investigate possible differences in the effect of repeated sleep restriction (RSR) during adolescence and adulthood on sleep homeostasis and spatial learning and memory ability.

DESIGN

The authors examined electroencephalograms of rats as they were subjected to 4-h daily sleep deprivation that continued for 7 consecutive days and assessed the spatial learning and memory by Morris water maze test (WMT).

PARTICIPANTS

Adolescent and adult rats.

MEASUREMENTS AND RESULTS

Adolescent rats exhibited a similar amount of rapid eye movement (REM) and nonrapid eye movement (NREM) sleep with higher slow wave activity (SWA, 0.5-4 Hz) and fewer episodes and conversions with prolonged durations, indicating they have better sleep quality than adult rats. After RSR, adult rats showed strong rebound of REM sleep by 31% on sleep deprivation day 1; this value was 37% on sleep deprivation day 7 in adolescents compared with 20-h baseline level. On sleep deprivation day 7, SWA in adult and adolescent rats increased by 47% and 33%, and such elevation lasted for 5 h and 7 h, respectively. Furthermore, the authors investigated the effects of 4-h daily sleep deprivation immediately after the water maze training sessions on spatial cognitive performance. Adolescent rats sleep-restricted for 7 days traveled a longer distance to find the hidden platform during the acquisition training and had fewer numbers of platform crossings in the probe trial than those in the control group, something that did not occur in the sleep-deprived adult rats.

CONCLUSIONS

Repeated sleep restriction (RSR) altered sleep profiles and mildly impaired spatial learning and memory capability in adolescent rats.