Normal Night Of Sleep Research Articles

Mean Duration for Cessation of Pain following Tonsillectomy Operation among the Patients of Otolaryngology Department in a Tertiary Care Hospital: A Descriptive Cross-sectional Study.

Tonsillectomy is one of the most common surgical procedures performed by Otolaryngologists world-wide. There are various techniques for tonsillectomy, but none of the techniques has been accepted as the best one universally. Despite the efforts of all the surgeon and use of recent techniques, some post-tonsillectomy morbidity is unavoidable. The main objective of our study is to find out the mean duration for cessation of pain among the patients following tonsillectomy operation in a tertiary care hospital. This is a descriptive cross-sectional study of 104 patients who underwent tonsillectomy in department of otolaryngology of Kathmandu Medical College from 1st August 2020 to 31st July 2021. Convenient sampling technique was used. Ethical Approval was taken from Ethical Clearance Committee of hospital (Reference number: 2207202005). Proforma containing visual analog score was given to every patient for scoring the severity of postoperative pain. The scoring of pain was done from 1st postoperative day till 14th postoperative day. Descriptive statistical analysis was done. One hundred four patients had undergone tonsillectomy in our hospital. The mean duration for cessation of pain was 10 (9.75±1.97) days with mean duration of analgesia taken of 11 (10.84±2.15) days. The mean duration after tonsillectomy operation for cessation of pain on drinking was 8 (7.51±1.19) days and on eating solids 12 (11.59±2.56) days. Patients reported the first normal night of sleep at seven (6.90±1.41) days and return to normal daily activities 11 (11.18±2.53) days. From the study concluded that the mean duration for cessation of pain after tonsillectomy is slightly lower than other similar study.

The Effect of Experimental Recuperative and Appetitive Post-lunch Nap Opportunities, With or Without Caffeine, on Mood and Reaction Time in Highly Trained Athletes.

Purpose: To investigate the effects of placebo (PLA), 20 min nap opportunity (N20), 5mg·kg−1 of caffeine (CAF), and their combination (CAF+N20) on sleepiness, mood and reaction-time after partial sleep deprivation (PSD; 04h30 of time in bed; study 1) or after normal sleep night (NSN; 08h30 of time in bed; study 2).Methods: Twenty-three highly trained athletes (study 1; 9 and study 2; 14) performed four test sessions (PLA, CAF, N20 and CAF+N20) in double-blind, counterbalanced and randomized order. Simple (SRT) and two-choice (2CRT) reaction time, subjective sleepiness (ESS) and mood state (POMS) were assessed twice, pre- and post-intervention.Results: SRT was lower (i.e., better performance) during CAF condition after PSD (pre: 336 ± 15 ms vs. post: 312 ± 9 ms; p < 0.001; d = 2.07; Δ% = 7.26) and NSN (pre: 350 ± 39 ms vs. post: 323 ± 32 ms; p < 0.001; d = 0.72; Δ% = 7.71) compared to pre-intervention. N20 decreased 2CRT after PSD (pre: 411 ± 13 ms vs. post: 366 ± 20 ms; p < 0.001; d = 2.89; Δ% = 10.81) and NSN (pre: 418 ± 29 ms vs. post: 375 ± 40 ms; p < 0.001; d = 1.23; Δ% = 10.23). Similarly, 2CRT was shorter during CAF+N20 sessions after PSD (pre: 406 ± 26 ms vs. post: 357 ± 17 ms; p < 0.001; d = 2.17; Δ% = 12.02) and after NSN (pre: 386 ± 33 ms vs. post: 352 ± 30 ms; p < 0.001; d = 1.09; Δ% = 8.68). After PSD, POMS score decreased after CAF (p < 0.001; d = 2.38; Δ% = 66.97) and CAF+N20 (p < 0.001; d = 1.68; Δ% = 46.68). However, after NSN, only N20 reduced POMS (p < 0.001; d = 1.05; Δ% = 78.65) and ESS (p < 0.01; d = 0.71; Δ% = 19.11).Conclusion: After PSD, all interventions reduced sleepiness and only CAF enhanced mood with or without napping. However, only N20 enhanced mood and reduced sleepiness after NSN. Caffeine ingestion enhanced SRT performance regardless of sleep deprivation. N20, with or without caffeine ingestion, enhanced 2CRT independently of sleep deprivation. This suggests a different mode of action of napping and caffeine on sleepiness, mood and reaction time.

Contrast-enhanced MRI T1 Mapping for Quantitative Evaluation of Putative Dynamic Glymphatic Activity in the Human Brain in Sleep-Wake States.

Background Evaluation of the glymphatic system with intrathecal contrast material injection has limited clinical use. Purpose To investigate the feasibility of using serial intravenous contrast-enhanced T1 mapping in the quantitative evaluation of putative dynamic glymphatic activity in various brain regions and to demonstrate the effect of sleep on glymphatic activity in humans. Materials and Methods In this prospective study from May 2019 to February 2020, 25 healthy participants (mean age, 25 years ± 2 [standard deviation]; 15 men) underwent two cycles of MRI (day and night cycles). For each cycle, T1 maps were acquired at baseline and 0.5, 1, 1.5, 2, and 12 hours after intravenous contrast material injection. For the night cycle, participants had a normal night of sleep between 2 and 12 hours. The time (tmin) to reach the minimum T1 value (T1min), the absolute difference between baseline T1 and T1min (peak ΔT1), and the slope between two measurements at 2 and 12 hours (slope[2h-12h]) were determined from T1 value-time curves in cerebral gray matter (GM), cerebral white matter (WM), cerebellar GM, cerebellar WM, and putamen. Mixed-model analysis of variance (ANOVA), Friedman test, and repeated-measures ANOVA were used to assess the effect of sleep on slope(2h-12h) and to compare tmin and peak ΔT1 among different regions. Results The slope(2h-12h) increased from the day to night cycles in cerebral GM, cerebellar GM, and putamen (geometric mean ratio [night/day] = 1.4 [95% CI: 1.2, 1.7], 1.3 [95% CI: 1.1, 1.4], and 2.4 [95% CI: 1.6, 3.6], respectively; P = .001, P < .001, and P < .001, respectively). Median tmin values were 0.5 hour in cerebral and cerebellar GM and putamen for both cycles. Cerebellar GM had the highest mean peak ΔT1, followed by cerebral GM and putamen in both day (159 msec ± 6, 99 msec ± 4, and 62 msec ± 5, respectively) and night (152 msec ± 6, 104 msec ± 6, and 58 msec ± 4, respectively) cycles. Conclusion Clearance of a gadolinium-based contrast agent was greater after sleep compared with daytime wakefulness. These results suggest that sleep was associated with greater glymphatic clearance compared with wakefulness. © RSNA, 2021 Online supplemental material is available for this article. See also the editorial by Anzai and Minoshima in this issue.

Differential interactions of age and sleep deprivation in driving and spatial perception by male drivers in a virtual reality environment.

We determined the effects of age and sleep deprivation on driving and spatial perception in a virtual reality environment. Twenty-two young (mean age: 22 years, range: 18-35) and 23 old (mean age: 71 years, range: 65-79) participants were tested after a normal night of sleep and a night of sleep deprivation. The participants drove a virtual car while responding to uni- and bilateral visual and auditory stimuli. Driving errors (crossing the lane borders), reaction times and accuracy to visual and auditory stimuli, performance in psychological tests, and subjective driving ability and tiredness were measured. Age had no effect on the number of driving errors, whereas sleep deprivation increased significantly especially the number of left lane border crossings. Age increased the number of stimulus detection errors, while sleep deprivation increased the number of errors particularly in the young and in the auditory modality as response omissions. Age and sleep deprivation together increased the number of response omissions in both modalities. Left side stimulus omissions suggest a bias to the right hemispace. The subjective evaluations were consistent with the objective measures. The psychological tests were more sensitive to the effects of age than to those of sleep deprivation. Driving simulation in a virtual reality setting is sensitive in detecting the effects of deteriorating factors on both driving and simultaneous spatial perception.

From incidental learning to explicit memory: The role of sleep after exposure to a serial reaction time task

This laboratory study explores whether sleep has different effects on explicit (recognition-based) and implicit (priming-based) memory. Eighty-nine healthy participants were randomly assigned to one of two experimental conditions: sleep or wake. All participants were previously exposed to an incidental learning session involving a 12-element deterministic second-order conditional sequence embedded in a serial reaction time task. The participants' explicit and implicit knowledge was assessed both immediately after the learning session (pretest) and after 12 h (posttest). For the sleep group, participants had a night of normal sleep between pretest and posttest, whereas the wake group spent 12 h awake during the day. The measures involved an explicit recognition test and an implicit priming reaction-time test with old fragments from a previously learned sequence and new fragments of a different control sequence. The sleep group showed statistically significant improvement between the pretest and the posttest in the explicit memory measure, whereas the wake group did not. In the implicit task, both groups improved similarly after a 12-h retention interval. These results suggest that throughout sleep, implicitly acquired information is processed offline to yield an explicit representation of knowledge incidentally acquired the night before.

Sleep deprivation reduces vagal tone during an inspiratory endurance task in humans.

Sleep deprivation alters inspiratory endurance by reducing inspiratory motor output. Vagal tone is involved in exercise endurance. This study aimed to investigate the effect of sleep deprivation on vagal tone adaptation in healthy subjects performing an inspiratory effort. Vagal tone was assessed using Heart Rate Variability normalized units of frequency domain component HF (high frequency) before, at the start, and the end of an inspiratory loading trial performed until exhaustion by 16 volunteers after one night of sleep deprivation and one night of normal sleep, where sleep deprivation reduced the inspiratory endurance by half compared to the normal sleep condition (30 min vs 60 min). At rest, heart rate was similar in sleep deprivation and normal sleep conditions. In normal sleep condition, heart rate increased during inspiratory loading task; this increase was greater in sleep deprivation condition. In normal sleep condition, vagal tone increased at the beginning of the trial. This vagal tone increase was absent in sleep deprivation condition. Sleep deprivation abolished vagal tone response to inspiratory load, possibly contributing to a higher heart rate during the trial and to a reduced inspiratory endurance. NCT02725190.

Quantifying Cognitive Impairment After Sleep Deprivation at Different Times of Day: A Proof of Concept Using Ultra-Short Smartphone-Based Tests.

Cognitive functioning is known to be impaired following sleep deprivation and to fluctuate depending on the time of day. However, most methods of assessing cognitive performance remain impractical for environments outside of the lab. This study investigated whether 2-min smartphone-based versions of commonly used cognitive tests could be used to assess the effects of sleep deprivation and time of day on diverse cognitive functions. After three nights of normal sleep, participants (N = 182) were randomised to either one night of sleep deprivation or a fourth night of normal sleep. Using the Karolinska WakeApp (KWA), participants completed a battery of 2-min cognitive tests, including measures of attention, arithmetic ability, episodic memory, working memory, and a Stroop test for cognitive conflict and behavioural adjustment. A baseline measurement was completed at 22:30 h, followed by three measurements the following day at approximately 08:00 h, 12:30 h, and 16:30 h. Sleep deprivation led to performance impairments in attention, arithmetic ability, episodic memory, and working memory. No effect of sleep deprivation was observed in the Stroop test. There were variations in attention and arithmetic test performance across different times of day. The effect of sleep deprivation on all cognitive tests was also found to vary at different times of day. In conclusion, this study shows that the KWA’s 2-min cognitive tests can be used to detect cognitive impairments following sleep deprivation, and fluctuations in cognitive performance relating to time of day. The results demonstrate the potential of using brief smartphone-based tasks to measure a variety of cognitive abilities within sleep and fatigue research.

Caffeine Use or Napping to Enhance Repeated Sprint Performance After Partial Sleep Deprivation: Why Not Both?

To compare the effect of a 20-minute nap opportunity (N20), a moderate dose of caffeine (CAF; 5mg·kg-1), or a moderate dose of caffeine before N20 (CAF+N) as possible countermeasures to the decreased performance and the partial sleep deprivation-induced muscle damage. Nine male, highly trained judokas were randomly assigned to either baseline normal sleep night, placebo, N20, CAF, or CAF+N. Test sessions included the running-based anaerobic sprint test, from which the maximum (Pmax), mean (Pmean), and minimum (Pmin) powers were calculated. Biomarkers of muscle, hepatic, and cardiac damage and of enzymatic and nonenzymatic antioxidants were measured at rest and after the exercise. N20 increased Pmax compared with placebo (P < .01, d = 0.75). CAF+N increased Pmax (P < .001, d = 1.5; d = 0.94), Pmin (P < .001, d = 2.79; d = 2.6), and Pmean (P < .001, d = 1.93; d = 1.79) compared with placebo and CAF, respectively. Postexercise creatine kinase increased whenever caffeine was added, that is, after CAF (P < .001, d = 1.19) and CAF+N (P < .001, d = 1.36). Postexercise uric acid increased whenever participants napped, that is, after N20 (P < .001, d = 2.19) and CAF+N (P < .001, d = 2.50) and decreased after CAF (P < .001, d = 2.96). Napping improved repeated-sprint performance and antioxidant defense after partial sleep deprivation. Contrarily, caffeine increased muscle damage without improving performance. For sleep-deprived athletes, caffeine before a short nap opportunity would be more beneficial for repeated sprint performance than each treatment alone.

The effect of one-night sleep deprivation on cognitive functions in healthy young adults.

IntroductionThe effects of acute sleep deprivation on cognitive function have not been clearly elucidated. The purpose of this study was to evaluate changes in cognitive function in healthy adults after one night of sleep deprivation.Material and MethodsTwenty-one healthy young adults (aged 18-30 years) underwent assessment of cognitive functions before and after one night of total sleep deprivation and an age- and gender-matched control group was assessed before and after a normal night sleep. Cognitive functions were assessed using the Montreal cognitive assessment (MOCA) and trail making test (TMT) parts A and B.ResultsGeneral linear model repeated measures demonstrated an insignificant effect for time × group (sleep deprivation) interaction for MOCA, TMT Part A, and TMT Part B scores after one-night sleep deprivation (p>.05 for all).ConclusionA single night of sleep deprivation, which can be inevitable in modern society, had no significant effect on cognitive performance in healthy adults.

Cortical gradients of functional connectivity are robust to state-dependent changes following sleep deprivation

Sleep deprivation leads to significant impairments in cognitive performance and changes to the interactions between large scale cortical networks, yet the hierarchical organization of cortical activity across states is still being explored. We used functional magnetic resonance imaging to assess activations and connectivity during cognitive tasks in 20 healthy young adults, during three states: (i) following a normal night of sleep, (ii) following 24hr of total sleep deprivation, and (iii) after a morning recovery nap. Situating cortical activity during cognitive tasks along hierarchical organizing gradients based upon similarity of functional connectivity patterns, we found that regional variations in task-activations were captured by an axis differentiating areas involved in executive control from default mode regions and paralimbic cortex. After global signal regression, the range of functional differentiation along this axis at baseline was significantly related to decline in working memory performance (2-back task) following sleep deprivation, as well as the extent of recovery in performance following a nap. The relative positions of cortical regions within gradients did not significantly change across states, except for a lesser differentiation of the visual system and increased coupling of the posterior cingulate cortex with executive control areas after sleep deprivation. This was despite a widespread increase in the magnitude of functional connectivity across the cortex following sleep deprivation. Cortical gradients of functional differentiation thus appear relatively insensitive to state-dependent changes following sleep deprivation and recovery, suggesting that there are no large-scale changes in cortical functional organization across vigilance states. Certain features of particular gradient axes may be informative for the extent of decline in performance on more complex tasks following sleep deprivation, and could be beneficial over traditional voxel- or parcel-based approaches in identifying realtionships between state-dependent brain activity and behavior.

The brain network organization during sleep onset after deprivation

ObjectiveAim of the present study is to investigate the alterations of brain networks derived from EEG analysis in pre- and post-sleep onset conditions after 40 h of sleep deprivation (SD) compared to sleep onset after normal sleep in 39 healthy subjects. MethodsFunctional connectivity analysis was made on electroencelographic (EEG) cortical sources of current density and small world (SW) index was evaluated in the EEG frequency bands (delta, theta, alpha, sigma and beta). ResultsComparing pre- vs. post-sleep onset conditions after a night of SD a significant decrease of SW in delta and theta bands in post-sleep onset condition was found together with an increase of SW in sigma band. Comparing pre-sleep onset after sleep SD versus pre-sleep onset after a night of normal sleep a decreased of SW index in beta band in pre-sleep onset in SD compared to pre-sleep onset in normal sleep was evidenced. ConclusionsBrain functional network architecture is influenced by the SD in different ways. Brain networks topology during wake resting state needs to be further explored to reveal SD-related changes in order to prevent possible negative effects of SD on behaviour and brain function during wakefulness. SignificanceThe SW modulations as revealed by the current study could be used as an index of an altered balance between brain integration and segregation processes after SD.

Vulnerability in Executive Functions to Sleep Deprivation Is Predicted by Subclinical Attention-Deficit/Hyperactivity Disorder Symptoms

BackgroundSleep loss results in state instability of cognitive functioning. It is not known whether this effect is more expressed when there is an increased cognitive demand. Moreover, while vulnerability to sleep loss varies substantially among individuals, it is not known why some people are more affected than others. We hypothesized that top-down regulation was specifically affected by sleep loss and that subclinical inattention and emotional instability traits, related to attention-deficit/hyperactivity disorder symptoms, predict this vulnerability in executive function and emotion regulation, respectively. MethodsHealthy subjects (ages 17–45 years) rated trait inattention and emotional instability before being randomized to either a night of normal sleep (n = 86) or total sleep deprivation (n = 87). Thereafter, they performed a neutral and emotional computerized Stroop task, involving words and faces. Performance was characterized primarily by cognitive conflict reaction time and reaction time variability (RTV), mirroring conflict cost in top-down regulation. ResultsSleep loss led to increased cognitive conflict RTV. Moreover, a higher level of inattention predicted increased cognitive conflict RTV in the neutral Stroop task after sleep deprivation (r = .30, p = .0055) but not after normal sleep (r = .055, p = .65; interaction effect β = 6.19, p = .065). This association remained after controlling for cognitive conflict reaction time and emotional instability, suggesting domain specificity. Correspondingly, emotional instability predicted cognitive conflict RTV for the emotional Stroop task only after sleep deprivation, although this effect was nonsignificant after correcting for multiple comparisons. ConclusionsOur findings suggest that sleep deprivation affects cognitive conflict variability and that less stable performance in executive functioning may surface after sleep loss in vulnerable individuals characterized by subclinical symptoms of inattention.

Motorcycling performance and sleepiness during an extended ride on a dynamic simulator: relationship with stress biomarkers

Objective: Powered two-wheelers (PTW) make up a large proportion of fatal accidents. The aim of this study was to investigate the effects of time-of-day and total sleep deprivation (SD) on simulated motorcycling performance during extended riding sessions (60 min), while evaluating stress mechanisms. Approach: A total of 16 healthy males participated in four simulated motorcycling sessions at 07:00, 11:00, 15:00 and 19:00, including city (8 min), country (2 min) and highway pathways (40 min), after a normal night of sleep and after total SD (30 h), in a randomized counterbalanced order. The recorded motorcycle parameters included: variation of lateral position, number of inappropriate line crossings (ILC), falls, riding errors, speed and speed limit violations. Subject parameters included the number of microsleeps in each pathway, the number of lapses during the 3-min psychomotor vigilance task (PVT—Brief version), and the Karolinska sleepiness scale (KSS) score. Saliva samples were used to assess cortisol (sC), α-amylase (sAA), and chromogranin-A (sCgA). ANOVAs and Pearson’s correlation analysis were performed between these variables. Main results: Most parameters were influenced by an interaction effect between ‘Motorcycling pathways’ × ‘SD’ (speed (p < 0.05), legal speed violations (p < 0.01), variation of lateral position (p < 0.001), falls (p < 0.001), EEG-microsleeps (p < 005)). An interaction effect between ‘SD’ × ‘Time-of-day’ influenced the number of ILCs (p < 0.01), sC (p < 0.05) and sCgA (p < 0.05) levels. SD affected KSS scores (p < 0.001) and PVT lapses (p < 0.05). The highest disturbances were associated with highway motorcycling simulation. Significance: Sleepiness due to circadian or SD and fatigue effects significantly affect riding and increase the risks involved with PTWs. The activation of both stress systems seems not sufficient to alleviate these deleterious effects

Partial and Total Sleep Deprivation Interferes With Neural Correlates of Consolidation of Fear Extinction Memory

BackgroundWe assessed the impact of total and partial sleep loss on neural correlates of fear conditioning, extinction learning, and extinction recall in healthy young adults. MethodsParticipants (56.3% female, age 24.8 ± 3.4 years) were randomized to a night of normal sleep (NS) (n = 48), sleep restriction (SR) (n = 53), or sleep deprivation (SD) (n = 53). All completed fear conditioning and extinction learning phases the following morning. Extinction recall was tested in the evening of the same day. Task-based contrasts were modeled at the beginning of, at the end of, and across the fear conditioning and extinction learning phases, and at the beginning of extinction recall. These contrasts were compared among the 3 groups by means of analysis of variance. Nonparametric permutation corrected analyses using a cluster-determining threshold of p < .005 and a familywise error of p < .05. ResultsAt the end of fear conditioning, NS activated medial prefrontal regions, SR activated motor areas, and participants in the SD group showed no significant activations. Across extinction learning, only NS activated both salience (fear) and extinction (regulatory) areas. For extinction recall, SD activated similar regions as NS across extinction learning, while SR activated salience and motor areas. During early fear conditioning, compared with NS, SD activated more medial prefrontal and SR activated more salience network areas. For extinction recall, NS activated more prefrontal areas and SD activated more of both salience- and extinction-related areas than SR. ConclusionsRelative to NS, SR may enhance fear-related and diminish extinction-related activity, whereas SD may delay engagement of extinction learning. Findings may have clinical implications for populations and occupations in which sleep loss is common.

Sleep deprivation and compensatory cognitive effort on a visual information processing task.

Total sleep deprivation (TSD) is often associated with worse performance on tasks of attention and working memory, but some studies show no performance changes. One possibility is that greater compensatory cognitive effort is put forth to achieve similar results after TSD. We aimed to better understand the relationship between TSD, cognitive engagement, and performance outcomes following TSD. Twenty healthy adults completed cognitive testing following a night of normal sleep and again after ~55 hours of TSD. Participants detected target letters in low (3-item) and high (10-item) load visual letter displays on the span of apprehension task with concurrent pupillometry, a measure of cognitive effort. We found significantly poorer detection accuracy and marginally longer response times following TSD across both arrays. In both arrays, significantly greater preparatory pupillary responses were found just prior to array onset. There was also a significant session by array interaction for pupillary responses, such that significantly greater dilation was found for the 3-letter array after TSD, while a nonsignificant decline in dilation was found following the 10-letter array after TSD. These results suggest a complex relationship between attentional control and cognitive resource allocation following TSD. Sleep-deprived individuals may allocate more compensatory cognitive effort to easier tasks but choose to disengage from more challenging cognitive tasks that have little perceived reward or probability of success to preserve diminishing cognitive resources. More work is needed to better delineate the underlying neurological systems involved in these processing load-dependent attentional control mechanisms after TSD.

Partial sleep deprivation affects endurance performance and psychophysiological responses during 12-minute self-paced running exercise

PurposeThis study aimed to investigate the effects of partial sleep deprivation (PSD) on physical performance and psychophysiological responses during 12-minute self-paced running exercise. MethodsTwenty runners (20.8±1.1 years, 70.6±4.9 kg, 175.1±3.9 cm) performed, in a randomized order, two running self-paced field exercises after a normal sleep night (CONT, bedtime from 22:30 h to 06:30 h) and one night of PSD (bedtime from 00:30 h to 04:30 h). Core temperature and motivation were recorded before exercise. Speed, covered distance, heart rate (HR), rating of perceived exertion (RPE) and respiratory parameters (i.e., minute ventilation (VE), oxygen uptake (VO2) and carbon dioxide production (VCO2)) were assessed during exercise. Blood lactate concentration [La] was assessed 2 min after exercise. Simple reaction time (SRT), mood and barrage test (BT) were assessed before and after exercise. ResultsHigher RPE (p=0.01, d=0.90) and lower physical performance (i.e., p=0.001, d=0.59 for running speed and p=0.01, d=0.7 and Δ (%)=-6% for covered distance), following PSD, were obtained compared to CONT. Similarly, PSD attenuated core temperature (p=0.01, d=0.84), HR (p=0.006, ɳp2=0.45), VE (p=0.001, ɳp2=0.73), VO2 (p=0.001, ɳp2=0.96), BT (p<0.0005, ɳp2=0.86), SRT (p=0.0009, ɳp2=0.44) and mood (p<0.0005). However, VCO2, [La] and motivation score were not affected by sleep conditions. ConclusionThe decrease of running performance and the increase of physical discomfort after PSD could be the origin of the lower cardio-respiratory responses to the 12-minute self-paced exercise. Effective strategies should be introduced to overcome the deterioration of physical performance and physiological responses after PSD.

The association between REM sleep and decision-making: Supporting evidences

Studies suggest that REM sleep is important for the maintenance of prefrontal cortex functioning. Therefore, reducing REM sleep may have an impact on cognitive functions such as impulse control and decision-making processes. This study examined the association between impulsiveness and sensation seeking personality traits, REM sleep and performance on a decision-making computer task following a habitual night of sleep and a partial sleep deprivation (PSD) condition with advanced wake-up time. Eighteen young adults participated in two experimental conditions: a control (habitual bedtime and wake time) and a 50% PSD with an advanced wake time. Impulsiveness and sensation seeking personality traits were measured with a personality inventory (NEO-PI-3), sleep was assessed using standard polysomnography and the Iowa Gambling Task (IGT) was completed at noon following each sleep condition. Results showed that when sleep deprived, participants choose more often to play riskier decks of cards during the last half of the IGT. Results also showed that REM sleep duration and REM sleep deprivation were associated with riskier decisions on the IGT. Moreover, impulsiveness was associated with riskier decisions after a normal night of sleep. These findings suggest that REM sleep duration and impulsiveness are important factors to consider while investigating decision-making processes under conditions of uncertainty and risk.

0317 Impact of Recurrent Partial Sleep Loss Combined with Acute Exercise on Circulating and Adipose Tissue Levels of Leptin, Adiponectin and Ghrelin in Healthy Young Individuals

Abstract Introduction Chronic sleep loss and aerobic exercise have opposing effects on body weight maintenance. The effects of sleep loss on circulating levels of the orexigenic hormone ghrelin and the anorexigenic hormone leptin have been extensively studied. In contrast, how these changes interact with acute exercise, and whether these changes are reflected at the tissue level, remains poorly understood. Methods In a randomized, 2 session, crossover design, 16 normal-weight young men were studied following three nights of partial sleep deprivation (4.25 hr sleep opportunity each night) and three nights of normal sleep (8.5-h sleep opportunity), monitored in a sleep laboratory. Each condition was followed by 30 min of intense morning ergometer cycling. Plasma levels of leptin and ghrelin, as well adipose tissue mRNA levels of leptin and adiponectin, were measured before and after each exercise intervention. Results In response to acute exercise, circulating levels of both leptin (ANOVA time effect: P&amp;lt;0.001) and ghrelin (time: P&amp;lt;0.001) decreased immediately (+15 min), and remained significantly lower +30, +60 and +240 min post exercise for leptin (all P&amp;lt;0.05), and up until +30 min post exercise for ghrelin. These effects were seen regardless of sleep condition (ANOVA sleep condition: P&amp;gt;0.10). In adipose tissue, mRNA expression of leptin and adiponectin was not different between the sleep conditions (ANOVA sleep condition: P&amp;gt;0.10). In contrast, mRNA levels of leptin decreased (P=0.017), whereas adiponectin mRNA increased (P=0.010) 3.5 hours post vs. pre exercise. The decrease in leptin in response to exercise appeared to mainly occur following sleep loss (P=0.066) and not after normal sleep (P=0.38). Conclusion Our results suggest that both circulating and adipose tissue levels of appetite-regulating hormones are altered in response to acute aerobic exercise, in a manner that does not depend on prior sleep history. Whether these findings apply to older, female, or metabolically ill individuals - and whether they may differ in response to circadian misalignment, or evening exercise - remains to be established. Support The Swedish Society for Medical Research, the Swedish Society of Medicine, the Swedish Research Council and the Göran Gustafsson; Swedish Brain; Åke Wiberg and NovoNordisk Foundations.

0548 Overnight Memory Consolidation in Insomnia versus Normal and Experimentally Disrupted Sleep

Abstract Introduction Healthy sleep is assumed to play an important role in the consolidation of newly acquired memories. Evidence suggest that periods of sleep after learning facilitates memory consolidation relative to wakefulness. Insomnia is associated with cognitive impairment but few studies have assessed overnight memory consolidation. We compared overnight consolidation in people with insomnia to a group of good sleepers who were randomised to either a normal night of sleep (uninterrupted sleep, US) or one night of sleep continuity disruption via forced awakenings (FA). Methods 51 good sleepers (37 female; mean age: 24 years, SD: 3.63), randomised to either one night of US (n=24) or one night of FA (n=27), were compared to 27 participants meeting criteria for insomnia disorder (23 female; mean age: 53 years, SD: 8.34) who were assessed at baseline as part of a randomised controlled trial of digital cognitive-behavioural therapy. Overnight memory consolidation (difference in correctly recalled word pairs between evening and morning recall) was assessed using the same word-pair task and protocol in the two lab-based studies. Results Overnight memory consolidation was significantly lower in the insomnia (mean: 5.4, SD: 5.8, p=0.001) and the FA (mean: 6.7, SD: 4.1, p&amp;lt;0.001) group compared to the US group (mean: 11.6, SD: 5.3). However, when adjusted for age only the FA group, but not the insomnia group, showed significantly lower memory performance than the US group. Conclusion While our findings suggest that overnight memory consolidation is impaired in insomnia relative to normal sleep we cannot rule out an age-related explanation given the difference in ages between the study samples. Future work will assess whether overnight consolidation improves following cognitive behavioural therapy. Support The research was supported by the National Institute for Health Research (NIHR) Oxford Biomedical Research Centre (BRC) and the Dr Mortimer and Theresa Sackler Foundation. The views expressed are those of the authors and not necessarily those of the NHS, the NIHR or the Department of Health.

Effect of Angle of View and Partial Sleep Deprivation on Distance Perception.

The present study aimed to investigate the effects of intensive effort on egocentric distance perception according to different angles of view after sleep deprivation at the beginning (SDB) or at the end (SDE) of the night and after a normal sleep night (NNS). Ten male students soccer players (age 22.8 ± 1.3 years; body mass 72.0 ± 10.4 kg; body height 180.0 ± 3.0 cm) performed a repeated cycling (RS) exercise (10 × 6 s maximal cycling with 24 s in between) after SDB, SDE, and NNS. They were asked to estimate three distances (i.e. 15, 25, and 35 m) before and after RS from different angles of view [i.e. in front (0°) and in side (45° left and 45° right)]. For 35 m, distance estimation was better during NNS compared to SDB and SDE for the front and the two side angles either before or after RS (p < 0.05). Concerning 25 m, distance estimation was better after compared to before RS for the front angle during the NNS session (p < 0.05). For 15 m, distance estimation was better during NNS than SDB and SDE for the front and both side angles after RS (p < 0.05). We concluded that partial sleep deprivation negatively affected the estimation of the egocentric distance for the three angles of view either at rest or after RS exercise.