Psychomotor Vigilance Task Reaction Time Research Articles

Alteration in neural oscillatory activity and phase‐amplitude coupling after sleep deprivation: Evidence for impairment and compensation effects

SummaryInsufficient sleep can significantly affect vigilance and increase slow‐wave electroencephalographic power as homeostatic sleep pressure accumulates. Phase‐amplitude coupling is involved in regulating the spatiotemporal integration of physiological processes. This study aimed to examine the functional associations of resting‐state electroencephalographic power and delta/theta‐gamma phase‐amplitude coupling from the prefrontal cortex (PFC) to posterior regions with vigilance performance after sleep deprivation. Forty‐six healthy adults underwent 24‐hr sleep deprivation with resting‐state electroencephalographic recordings, and vigilant attention was measured using the Psychomotor Vigilance Task. Power spectral and phase‐amplitude coupling analyses were conducted, and correlation analysis was utilized to reveal the relationship between electroencephalographic patterns and changes in vigilance resulting from sleep deprivation. Sleep deprivation significantly declined vigilance performance, accompanied by increased resting‐state electroencephalographic power in all bands and delta/theta‐gamma phase‐amplitude coupling. The increased theta activity in centro‐parieto‐occipital areas significantly correlated with decreased mean and slowest response speed. Conversely, the increased delta‐low gamma and theta‐high gamma phase‐amplitude couplings negatively correlated with the deceleration of the fastest Psychomotor Vigilance Task reaction times. These findings suggest that sleep deprivation affects vigilance by altering electroencephalographic spectral power and information communication across frequency bands in different brain regions. The distinct effects of increased theta power and delta/theta‐gamma phase‐amplitude coupling might reflect the impairment and compensation of sleep deprivation on vigilance performance, respectively.

Ad libitum caffeine consumption, cognitive performance, and sleep in special forces soldiers during a 96-h combat exercise.

This observational study investigated the effects of sleep deprivation and ad libitum caffeine consumption on cognitive performance, risk behavior, and mood among 28 Israeli Special Forces (SF) soldiers (mean age: 20.57 ± 0.92 years) during a 96-hour combat exercise. Actigraphy was used to monitor sleep and activity; cognitive function, risk-taking propensity, mood states, and self-reported sleepiness were assessed using the Psychomotor Vigilance Task (PVT), Evaluation of Risks Scale (EVAR), Profile of Mood States (POMS), Karolinska Sleepiness Scale (KSS); and caffeine consumption by questionnaire at 0, 50, and 96 hours. For analyses, participants were divided into Low (<400 mg) and High (≥400 mg) caffeine consumption groups. The soldiers hiked 108.5 ± 0.52 km and slept for 12.7 ± 0.5 h, with a notable transition from multiple short sleep epochs in the initial 50 hours to a consolidated 5-hour sleep period subsequently. In the High caffeine group, PVT reaction time was faster (p = 0.024) compared to the Low caffeine group, with fewer premature response errors (p = 0.026). However, this group showed increased risk-taking (p = 0.037), particularly reduced Self-Control (p = 0.010). No significant impact of ad libitum caffeine intake on mood was observed. However, degradation over the course of the exercise in both groups in mood states, including anger, fatigue, tension, and vigor, was noted (p < 0.05). KSS scores increased significantly at 50 and 96 h (p < 0.001). These results suggest that while caffeine enhances cognitive function, its ad libitum consumption did not consistently improve these measures in this cohort of SF soldiers. The study highlights the complex relationship between sleep deprivation and caffeine intake and their combined effects on soldiers' cognitive and behavioral functions, indicating a need for evidence-based caffeine use guidelines for using caffeine in military settings.

Effect of total sleep deprivation on effective EEG connectivity for young male in resting-state networks in different eye states

BackgroundMany studies have investigated the effect of total sleep deprivation (TSD) on resting-state functional networks, especially the default mode network (DMN) and sensorimotor network (SMN), using functional connectivity. While it is known that the activities of these networks differ based on eye state, it remains unclear how TSD affects them in different eye states. Therefore, we aimed to examine the effect of TSD on DMN and SMN in different eye states using effective functional connectivity via isolated effective coherence (iCoh) in exact low-resolution brain electromagnetic tomography (eLORETA).MethodsResting-state electroencephalogram (EEG) signals were collected from 24 male college students, and each participant completed a psychomotor vigilance task (PVT) while behavioral data were acquired. Each participant underwent 36-h TSD, and the data were acquired in two sleep-deprivation times (rested wakefulness, RW: 0 h; and TSD: 36 h) and two eye states (eyes closed, EC; and eyes open, EO). Changes in neural oscillations and effective connectivity were compared based on paired t-test.ResultsThe behavioral results showed that PVT reaction time was significantly longer in TSD compared with that of RW. The EEG results showed that in the EO state, the activity of high-frequency bands in the DMN and SMN were enhanced compared to those of the EC state. Furthermore, when compared with the DMN and SMN of RW, in TSD, the activity of DMN was decreased, and SMN was increased. Moreover, the changed effective connectivity in the DMN and SMN after TSD was positively correlated with an increased PVT reaction time. In addition, the effective connectivity in the different network (EO-EC) of the SMN was reduced in the β band after TSD compared with that of RW.ConclusionThese findings indicate that TSD impairs alertness and sensory information input in the SMN to a greater extent in an EO than in an EC state.

0187 Hypnograms for 365 Nights Predicts Subjective Sleep Quality in Healthy Adults: Results from the Ultra Long-Term Sleep (ULTS) Study

Abstract Introduction Sleep quality is fundamental to our somatic and mental health. However, the relationship between subjective sleep quality and sleep architecture remains poorly understood. New wearable or minimally invasive technologies facilitate the recording of electroencephalography (EEG) with lower spatial resolution than standard EEG but much greater longitudinal dispersion. This enables investigation of day-to-day variation in sleep measured directly with EEG. This study will compare EEG-derived sleep parameters with covariates such as sustained attention and subjective sleep quality. Methods Twenty-five healthy adults were implanted with a two-channel subcutaneous EEG (sqEEG) lead. Twenty subjects completed the 1-year protocol (average 32±13 years of age). Their sqEEG signals were recorded each night for 1 year alongside a morning 3-minute Psychomotor Vigilance Task (PVT) and self-reported sleep quality, which included Karolinska Sleepiness Scale (KSS). A deep learning model, U-Sleep, was fine-tuned on sqEEG with synchronized gold standard polysomnography used as ground truth. Hypnograms and sleep parameters were thus automatically calculated. Results Subjective sleep quality measured by KSS revealed a moderate negative correlation with rapid-eye-movement (REM) duration (r=-0.31, 95% CI=(-0.31, -0.31)), and total sleep time (TST) (r=-0.31, 95% CI=(-0.31, -0.31)). There was a moderate correlation between KSS and mean PVT reaction time (r=0.21, 95% CI=(0.21, 0.22)). There was a low negative correlation between PVT and TST (r=-0.1). Preliminary results indicate a moderate correlation between sleep parameters and subjective sleep quality. The correlations with PVT were lower, which suggests that 3-minute PVT is not sensitive to TST in normal sleep. However, the correlation between PVT and KSS suggests that PVT does predict subjective sleep quality, but to a smaller degree than standard sleep parameters. Conclusion Measuring day-to-day variation in high-quality EEG-based sleep recordings has the potential of creating a new branch in sleep medicine. Patients can be evaluated not only by findings in a single recording but the stability and variation of all findings can be analyzed. Preliminary results suggest that subjective sleep quality can be predicted directly from sqEEG and potentially be explained by behavioral factors in a subsequent cause-effect analysis. Support (if any) The project is supported by Innovation Fund Denmark, UNEEG medical, and T&amp;W Engineering.

Dissociable brainstem functional connectivity changes correlate with objective and subjective vigilance decline after total sleep deprivation in healthy male subjects.

The maintenance of vigilance relies on the activation of the cerebral cortex by the arousal system centered on the brainstem. Previous studies have suggested that both objective and subjective vigilance are susceptible to sleep deprivation. This study aims to explore the alterations in brainstem arousal system functional connectivity (FC) and its involvement in these two types of vigilance decline following total sleep deprivation (TSD). Thirty-seven healthy male subjects underwent two counterbalanced resting-state fMRI scans, once in rested wakefulness (RW) and once after 36 h of TSD. The pontine tegmental area and caudal midbrain (PTA-cMidbrain), the core regions of the brainstem arousal system, were chosen as the seeds for FC analysis. The difference in PTA-cMidbrain FC between RW and TSD conditions was then investigated, as well as its associations with objective vigilance measured by psychomotor vigilance task (PVT) and subjective vigilance measured by Stanford Sleepiness Scale. The sleep-deprived subjects showed increased PTA-cMidbrain FC with the thalamus and cerebellum and decreased PTA-cMidbrain FC with the occipital, parietal, and sensorimotor regions. TSD-induced increases in PVT reaction time were negatively correlated with altered PTA-cMidbrain FC in the dorsolateral prefrontal cortex, extrastriate visual cortex, and precuneus. TSD-induced increases in subjective sleepiness were positively correlated with altered PTA-cMidbrain FC in default mode regions including the medial prefrontal cortex and precuneus. Our results suggest that different brainstem FC patterns underlie the objective and subjective vigilance declines induced by TSD.

A brief assessment of eye blink drowsiness immediately prior to or following driving detects drowsiness related driving impairment.

Drowsy driving is a major cause of fatal and serious injury motor vehicle accidents. The inability objectively to assess drowsiness has hindered the assessment of fitness to drive and the development of drowsy driving regulations. This study evaluated whether spontaneous eye blink parameters measured briefly pre- and post-drive could be used to detect drowsy driving impairment. Twelve healthy participants (6 female) drove an instrumented vehicle for 2 h on a closed-loop track during a rested (8-10 h awake) and an extended wake condition (32-34 h awake). Pre- and post-drive, the participants completed a 5 min eye blink task, a psychomotor vigilance task (PVT), and the Karolinska sleepiness scale (KSS). Whole drive impairment was defined as >3.5 lane departures per hour. Severe end of drive impairment was defined as ≥2 lane departures in the last 15 min. The pre-drive % of time with eyes closed best predicted the whole drive impairment (area under the curve [AUC] 0.87). KSS had similar prediction ability (AUC 0.85), while PVT reaction time (AUC 0.72) was less accurate. The composite eye blink parameter, the Johns drowsiness scale was the best retrospective detector of severe end of drive impairment (AUC 0.99). The PVT reaction time (AUC 0.92) and the KSS (AUC 0.93) were less accurate. Eye blink parameters detected drowsy driving impairment with an accuracy that was similar to, or marginally better than, PVT and KSS. As eye blink measures are simple to measure, are objective and have high accuracy, they present an ideal option for the assessment of fitness for duty and roadside drowsiness.

Changes in speech and voice characteristics following two hours and eight hours of acute sleep deprivation

Objectives: Sleep loss is known to affect aircrew performance. The study intended to examine the changes in speech and voice characteristics following 2 and 8 h of sleep deprivation for their potential usage as screening methods for detecting sleep deprivation in aircrew. Material and Methods: In a repeated measure design, the study analyzed the effects of 2 h and 8 h of acute sleep deprivation on speech and voice parameters among 30 healthy male volunteers by analyzing standard paragraph reading for 15 s and sustained vowel/a/for 6 s using the commercially available Dr. Speech Voice assessment tool. Subjective appreciation of sleepiness and fatigue was measured by Stanford Sleepiness Scale (SSS) and Chalder’s Fatigue Scale (CFS), respectively, and objective assessment of performance by psychomotor vigilance task (PVT). Results: The subjective markers (SSS and CFS) and objective parameters (PVT reaction time) indicated evidence of fatigue onset even after 2-h of sleep deprivation. In speech parameters, average fundamental frequency (F0), F0 range, and % silence time decreased significantly; whereas, speech time, percent voiceless time, and mean percent voiced time increased significantly following 8-h of sleep deprivation, while percent silence time decreased significantly after 8-h of sleep deprivation . In voice parameters, shimmer % and NNE increased significantly while harmonic-to-noise ratio and signal-to-noise ratio decreased significantly after 8-h of sleep deprivation. Mean shimmer % showed a significant change even after 2-h of sleep deprivation. Conclusion: The findings of the study bring out significant changes in both the speech and voice spectrum following periods of acute sleep deprivation. The changes were more pronounced during sleep deprivation of 8-h as compared to 2-h. These findings have potential application in aviation environment in objective detection of aircrew fatigue following periods of continuous wakefulness and resultant sleep deprivation.

Towards a new approach to detect sleepiness: Validation of the objective sleepiness scale under simulated driving conditions

The Objective Sleepiness Scale (OSS) was developed to detect and quantify sleepiness on the basis of two direct and reliable sleepiness indicators: EEG and EOG. The present study aims to test whether the OSS can be used to detect sleepiness episodes that impair performance on driving and vigilance tasks accurately and with a good time synchronization. Forty-three healthy volunteers performed monotonous driving sessions on a simulator and the psychomotor vigilance task (PVT) in a normal sleep condition and after partial sleep deprivation. OSS reliability and time synchronization for sleepiness detection were tested on driving (standard deviation of vehicle lateral position and off-road duration) and PVT (reaction time and lapses). Inter-rater reliability of the scale was evaluated by two blinded scorers. Results show that the OSS score indicates higher sleepiness in sleep deprivation conditions (p < 0.001) and with time-on-task. Differences of performance between OSS score calculated with multiple pairwise comparisons, indicate OSS score increase when driving performance (SDLP and off-road duration) decreases (p < 0.001 for comparisons between OSS stages 0 vs 2, 0 vs 3, 1 vs 2 and p < 0.05 for 1 vs 3). Reaction time during PVT is also related to the OSS score (p < 0.05 for OSS values from 0 to 2, 0 to 3, 1 to 2 and 1 to 3). There is no proportional relation between OSS score and performance impairment, but a threshold effect between levels 1 and 2 of the scale is observed. Positive outcomes are also obtained for time synchronization of the OSS assessed on driving performance (p < 0.001 for both SDLP and off-road duration). Finally, inter-rater agreement is found to be considerable. The results allow us to consider using the Objective Sleepiness Scale as a tool for research on sleepiness.

0020 Investigation of Seasonal Changes in Self-Reported Sleep Quality and Psychomotor Vigilance Task Outcomes: Results From the Ultra Long-Term Sleep (ULTS) Study

Abstract Introduction Although sleep is fundamental for human well-being, factors that contribute to an individual’s experience and report of sleep quality remain poorly understood. Utilizing that sleepiness is known to impact vigilance performance, this study sets out to explore how self-reported sleep quality changes with behavioral performance and how this variation is affected by seasonal changes. Methods This work is an interim analysis of self-reported sleep quality and behavioral performance data collected in the Ultra Long-term Sleep (ULTS) study (ClinicalTrials.gov Identifier: NCT04513743). In the study 20 healthy participants (average 33±13 years of age) were enrolled for 365 continuous days to observe the seasonal variation in sleep and cognitive performance. The outcome from the daily psychomotor vigilance task (PVT) and sleep questionnaire is analyzed and reported. The sleep questionnaire is a composite of questions from the Sleep Satisfaction Tool, the Karolinska Sleep Diary, questions regarding feelings of pain and outside disturbances, easiness of waking up, and the Karolinska Sleepiness Scale (KSS). The PVT was designed for self-administered high-frequency testing and has a short 3-minute test period. Monthly changes were examined from June to November. This period was chosen since all subjects were active. Results The first eight participants have now completed the study. Repeated measures correlations between KSS and mean PVT reaction time showed moderate but highly robust associations between the two measures over time (r=0.2; 95% CI 0.18-0.23). From the data collected thus far from the entire population, fastest PVT mean reaction times were found on Saturdays and slowest on Tuesdays. Similarly, KSS had best scores in weekends. There was an overall increase in mean PVT reaction time during the investigated period from June to November. This was also observed in KSS. Conclusion Our findings show a moderate correlation between the mean PVT reaction time and Karolinska Sleepiness Scale with up to 365 datapoints per subject with weekly and seasonal trends observed. Support (If Any) This research is supported by Innovation Fund Denmark.

Time of day, time of sleep, and time on task effects on sleepiness and cognitive performance of bus drivers.

Optimal cognitive performance might prevent vehicle accidents. Identifying time-related circadian and homeostatic parameters having an impact on cognitive performance of drivers may be crucial to optimize drivers' performance. In this prospective study conducted on bus drivers, two drivers alternated driving during a 24-h round trip and were accompanied by an interviewer. Each driver was tested using Karolinska Sleepiness Scale (KSS) and the reversed digit span Wechsler Working Memory test before the start of his shift and then every 6h during a "work/driving" day. Psychomotor Vigilance Task (PVT) was assessed before and after the journey. Linear mixed model was used to explore the factors affecting cognitive performance and sleepiness in univariate and multivariate analysis. Among 35 bus drivers, the effect of time of day on working memories was statistically significant (p = 0.001), with the lowest working memory scores at 04:00 am (± 1). The highest score of subjective sleepiness was also at 04:00 am (± 1). The time on task parameter affected sleepiness significantly (p = 0.024) and sleepiness was significantly associated with decreased working memory. Psychomotor Vigilance Task reaction time mean and the number of minor lapses were significantly increased after the journey, which suggested decreased vigilance. In multivariable analysis, a longer interval between the beginning of working hours and testing time (B (95% CI) = 15.25 (0.49 to 30), p = 0.043) was associated with higher (i.e., slower) PVT reaction time mean. These results suggest that optimizing bus drivers' working schedules may improve drivers' sleepiness and cognitive performance and thus increase road safety.

Effects of Inositol-Enhanced Bonded Arginine Silicate Ingestion on Cognitive and Executive Function in Gamers.

Inositol stabilized arginine silicate (ASI) ingestion has been reported to increase nitric oxide levels while inositol (I) has been reported to enhance neurotransmission. The current study examined whether acute ASI + I (Inositol-enhanced bonded arginine silicate) ingestion affects cognitive function in e-sport gamers. In a double blind, randomized, placebo controlled, and crossover trial, 26 healthy male (n = 18) and female (n = 8) experienced gamers (23 ± 5 years, 171 ± 11 cm, 71.1 ± 14 kg, 20.7 ± 3.5 kg/m2) were randomly assigned to consume 1600 mg of ASI + I (nooLVL®, Nutrition 21) or 1600 mg of a maltodextrin placebo (PLA). Prior to testing, participants recorded their diet, refrained from consuming atypical amounts of stimulants and foods high in arginine and nitrates, and fasted for 8 h. During testing sessions, participants completed stimulant sensitivity questionnaires and performed cognitive function tests (i.e., Berg-Wisconsin Card Sorting task test, Go/No-Go test, Sternberg Task Test, Psychomotor Vigilance Task Test, Cambridge Brain Sciences Reasoning and Concentration test) and a light reaction test. Participants then ingested treatments in a randomized manner. Fifteen minutes following ingestion, participants repeated tests (Pre-Game). Participants then played their favorite video game for 1-h and repeated the battery of tests (Post-Game). Participants observed a 7–14-day washout period and then replicated the study with the alternative treatment. Data were analyzed by General Linear Model (GLM) univariate analyses with repeated measures using weight as a covariate, paired t-tests (not adjusted to weight), and mean changes from baseline with 95% Confidence Intervals (CI). Pairwise comparison revealed that there was a significant improvement in Sternberg Mean Present Reaction Time (ASI + I vs. PLA; p < 0.05). In Post-Game assessments, 4-letter Absent Reaction Time (p < 0.05), 6-letter Present Reaction Time (p < 0.01), 6-letter Absent Reaction Time (p < 0.01), Mean Present Reaction Time (p < 0.02), and Mean Absent Reaction Time (p < 0.03) were improved with ASI + I vs. PLA. There was a non-significant trend in Pre-Game Sternberg 4-letter Present Reaction time in ASI + I vs. PLA (p < 0.07). ASI + I ingestion better maintained changes in Go/No-Go Mean Accuracy and Reaction Time, Psychomotor Vigilance Task Reaction Time, and Cambridge Post-Game Visio-spatial Processing and Planning. Results provide evidence that ASI + I ingestion prior to playing video games may enhance some measures of short-term and working memory, reaction time, reasoning, and concentration in experienced gamers.

Individuals with and without military-related PTSD differ in subjective sleepiness and alertness but not objective sleepiness

Posttraumatic stress disorder-related sleep disturbances may increase daytime sleepiness and compromise performance in individuals with posttraumatic stress disorder. We investigated nighttime sleep predictors of sleepiness in Veterans with and without posttraumatic stress disorder. Thirty-seven post-9/11 Veterans with posttraumatic stress disorder and 47 without posttraumatic stress disorder (Control) completed a 48-h lab stay. Nighttime quantitative EEG and sleep architecture parameters were collected with polysomnography. Data from daytime sleepiness batteries assessing subjective sleepiness (global vigor questionnaire), objective sleepiness (Multiple Sleep Latency Tests) and alertness (psychomotor vigilance task) were included in analyses. Independent samples t-tests and linear regressions were performed to identify group differences in sleepiness and nighttime sleep predictors of sleepiness in the overall sample and within each group. Participants with posttraumatic stress disorder had higher subjective sleepiness (t = 4.20; p < .001) and lower alertness (psychomotor vigilance task reaction time (t = -3.70; p < .001) and lapses: t = -2.13; p = .04) than the control group. Objective daytime sleepiness did not differ between groups (t = -0.79, p = .43). In the whole sample, higher rapid eye movement delta power predicted lower alertness quantified by psychomotor vigilance task reaction time (β = 0.372, p = .013) and lapses (β = 0.388, p = .013). More fragmented sleep predicted higher objective sleepiness in the posttraumatic stress disorder group (β = −.467, p = .005) but no other nighttime sleep measures influenced the relationship between group and sleepiness. Objective measures of sleep and sleepiness were not associated with the increased subjective sleepiness and reduced alertness of the posttraumatic stress disorder group.

104 The influence of self-reported distractions on the Psychomotor Vigilance Task (PVT) in laboratory and field environments

Abstract Introduction The Psychomotor Vigilance Task (PVT) is a measure of vigilant attention that is commonly used in laboratory environments to assess the neurobehavioral impact of sleep loss and circadian misalignment. The PVT has been increasing in popularity for use in field environments; however, the potential for distraction is higher in the field compared to the lab. It is unclear how distractions experienced by individuals taking the PVT in the real world may influence reaction time metrics. We investigated the influence of self-reported distraction on PVT outcomes across laboratory and field environments. Methods We examined PVT data from five studies including short (n=36 participants, 3799 PVTs) and long-haul (n=75 participants, 3282 PVTs) airline personnel, control center personnel (n=5 participants, 96 PVTs), and healthy individuals who participated in a study involving at-home and laboratory assessments (n=12 participants, 486 and 310 PVTs). Individuals in all of the studies were asked to complete the five-minute NASA PVT at least three times daily. Participants were asked to indicate the number of distractions they experienced immediately after each PVT. Mean PVT reaction time (RT) and number of distractions were computed for each study and overall. Results Participants reported more distractions in field environments compared to the lab (short-haul=1.29 +/- 1.48, long-haul=0.66 +/- 1.07, control-center=1.20 +/- 1.37, at-home=0.86 +/- 1.36, laboratory=0.46 +/- 1.07) Across all studies, we found that PVT RT slowed as self-reported distractions increased (all studies combined: 0 distractions=PVT RT 275.7ms; 1=285.0ms; 2=304.0ms; 3=322.9ms; &amp;gt;4=408.6ms). These findings were similar for healthy participants completing PVTs at home (0 distractions=286.4ms; 1=309.9ms; 2=328.3ms; 3=369.8ms; &amp;gt;4=385.1ms) but were less consistent during in-lab assessments (0 distractions=278.7ms; 1=316.2ms; 2=396.2ms; 3=370.4ms; &amp;gt;4=354.4ms). These findings were similar for other PVT outcomes. Conclusion Participants reported more distractions in field environments compared to the laboratory. Our findings suggest that the number of distractions that individuals report experiencing while taking a PVT increases the reaction time registered by the device. Researchers should collect information about distractions during the PVT and should be aware that distractions may influence the recorded PVT reaction time. Support (if any) NASA Airspace Operations and Safety Program, System-Wide Safety Project

Impact Of Mental Fatigue On Force Control And Muscle Activation

Mental fatigue (MF) leads to performance declines in tasks requiring force control. However, the neuromuscular mechanisms leading to these declines are not well understood. PURPOSE: To determine the effect of MF on the ability to match a target force and identify associated changes in muscle activation in males and females. METHODS: Nineteen participants (10 female) performed one 10-s isometric dorsiflexion contraction at 20 and 50% maximum voluntary contraction (MVC) before and after completing 20 min of the psychomotor vigilance task (PVT). The PVT is a sustained attention reaction time (RT) task known to induce MF. Force, indwelling and surface electromyography (sEMG) of the tibialis anterior were measured prior to and immediately following the PVT. RESULTS: Mean values for all variables can be found in Table 1. PVT RT and subjective fatigue increased similarly in males and females over time, indicating successful induction of MF. Mean absolute force produced at 20% and 50% MVC increased in males and females from pre- to post-PVT. However, there were no significant changes in the root mean square error of force at either contraction intensity. sEMG amplitude declined after the PVT in the 20% MVC condition with a trend towards declining at 50% MVC in both males and females. This was accompanied by a slowing of motor unit discharge rate after the PVT at 20% MVC in both sexes, but only in males at 50% MVC. CONCLUSION: Inducing MF led to changes in mean force of submaximal isometric contractions. This was accompanied by a decline in agonist muscle activity, suggesting alterations to motor control in the presence of MF.Table 1: Impact of PVT

0302 One Week of Recovery Sleep is Insufficient to Restore Sustained Attention Performance Following Three Weeks of Chronic Sleep Restriction

Abstract Introduction Sleep loss negatively impacts many aspects of neurobehavioral performance, including sustained attention and reaction times. However, the time course of recovery from chronic sleep restriction (CSR) is not well understood. To explore this, we assessed the effects of 3 weeks of CSR followed by 1 week of recovery on psychomotor vigilance task (PVT) performance in healthy adults. Methods 8 healthy adults (27–71; 4f) participated in a 37-day inpatient study. The study consisted of 6 baseline (BL) days with 8–16 h time-in-bed, followed by 3 weeks of CSR (5-5.6h time-in-bed at night), and 1 week of recovery (RC; 8-10h time-in-bed). Sustained attention was assessed by 10-minute visual PVTs administered every 2h starting ~5h after wake (~4/day). Linear and generalized linear mixed models were used to compare average reaction times (RT) and number of lapses, respectively, from the last 3 days of baseline, CSR, and recovery. Results Average RT was almost twice as long at the end of CSR compared to baseline (p&amp;lt;0.0001). Moreover, it remained significantly slower than baseline by roughly 173ms, even after 1 week of recovery (p&amp;lt;0.0001). Similarly, there was a threefold increase in the number of lapses at the end of CSR compared to baseline (p&amp;lt;0.0001) which remained elevated after one week of recovery (p&amp;lt;0.0001). Conclusion One week of recovery sleep of 8-10 h/night following 3 weeks of chronic sleep restriction was insufficient for full recovery of sustained attention as assessed by PVT reaction time and number of lapses. This suggests that chronic sleep restriction has consequences on neurobehavioral performance that do not fully dissipate within one week. Support Study supported by P01AG009975 and conducted in the Brigham and Women’s Hospital Center for Clinical Investigation, part of Harvard Clinical and Translational Science Center supported by UL1TR001102. KMZ supported by a fellowship from the Finnish Cultural Foundation. RKY supported by T32HL007901 and F32HL143893. NV supported by T32HL007901 and F32AG051325.

0097 Effects of Experimental Sleep Disruption on Morning Cognitive Performance and Alertness

Abstract Introduction While sleep duration is known to affect next-day cognitive performance and alertness, largely in a dose-response manner, the effects of disrupted sleep (where one is awoken multiple times overnight, common in military settings) are much less understood. Therefore, we examined the effects of experimentally disrupted sleep on morning cognitive performance and alertness. Methods We tested 34 healthy participants (12 men, 22 women, 28.1±3.9 years; mean±SD) who slept for 8-hours time-in-bed on three consecutive nights with polysomnography in a controlled sleep lab. The final two nights were randomized and counterbalanced between an undisrupted and a disrupted sleep condition. On the disrupted sleep night, participants were awoken by auditory tones for a 5–10 min period every hour. The following morning, participants completed a cognitive test battery that included Karolinska Sleepiness Scale (KSS), 10-min psychomotor vigilance task (PVT), addition calculations (ADD), go/no-go (GNG), task switching (TS), and working memory (WM). Mixed effects models were used to test factors: condition (undisrupted vs. disrupted), condition-order, and their interaction. Results Significant (p&amp;lt;0.05) effects of condition (i.e., disrupted sleep caused worse performance) were found for PVT reaction time (RT), GNG RT, TS RT, WM percent correct, and KSS alertness ratings. Condition was not significant for number or percent correct on ADD, GNG, and TS. Condition-order was significant for TS percent correct, and significant interactions were found for ADD number correct and TS RT. Conclusion One night of sleep disruption caused significant negative effects on morning subjective alertness and on several, but not all, cognitive performance domains tested, including RT and WM. Condition-order and interaction effects were also found, indicating that some performance outcomes were impacted by possible learning effects over the study. Sleep disruption factors should be taken into account, especially in operational settings like the military where environmental factors (e.g., noise) disrupt sleeping conditions. Support Office of Naval Research, Code 34

Impact of robotic assistance on mental workload and cognitive performance of surgical trainees performing a complex minimally invasive suturing task.

Few studies have investigated the potential impact of robotic assistance on cognitive ergonomics during advanced minimally invasive surgery. The purpose of this study was to assess the impact of robotic assistance on mental workload and downstream cognitive performance in surgical trainees. Robot-naïve trainees from general surgery, urology and gynaecology, stratified by specialty and level of training, were randomised to either laparoscopic surgery (LS) or robotic-assisted laparoscopic surgery (RALS) and performed a time-limited, complex laparoscopic suturing task after watching a 5-min instructional video. The RALS group received an additional 5-min orientation to the robotic console. Subjective mental workload was measured using NASA Task Load Index. Concentration and executive cognitive function were assessed using Psychomotor Vigilance Task (PVT) and Wisconsin Card Sorting Test (WCST), respectively. A p value of 0.05 was considered significant. Sixteen senior residents (SR; ≥ PGY3) and 14 junior residents (JR; PGY1-2) completed the study. There was no difference in mental workload between LS and RALS. Within JR there was no difference in task completion time comparing LS versus RALS; however, LS was associated with impaired concentration post-task versus pre-task (PVT reaction time 306 versus 324ms, p = 0.03), which was not observed for RALS. In contrast, amongst SR, RALS took significantly longer than LS (10.3 vs. 14.5min, p = 0.02) and was associated with significantly worse performance on WCST (p < 0.01). Robotic assistance, in this setting, did not provide a technical performance advantage nor impact subjective mental workload with novice users regardless of level of surgery training. We observed a protective effect on cognitive performance offered by RALS to junior trainees with limited LS experience, yet a detrimental effect on senior trainees with greater LS ability and inadequate pre-study robotic training, suggesting that robotic consoles may be mentally taxing for robotic novices and consideration should be given to formal console training prior to initial clinical exposure.

Enhanced high-frequency precuneus-cortical effective connectivity is associated with decreased sensory gating following total sleep deprivation

Sleep deprivation decreases an individual's cognitive function. When cognitive impairment reaches a certain level, human errors occur and may even result in accidents. Previous research has shown that sensory gating is a basic mechanism in cognitive function, but only limited studies have so far reported how it is affected by sleep deprivation. This study aimed to analyze the effects of sleep deprivation on sensory gating and its cognitive and neural mechanisms. Thirty-six healthy subjects participated in our study. The resting-state, auditory P50-task electroencephalography (EEG) recordings and the psychomotor vigilance task (PVT) were performed at resting wakefulness (RW) and after 36 h of total sleep deprivation (TSD). Changes in P50 suppression before and after sleep deprivation were recorded, and the isolated effective coherence (iCoh) was employed for analyzing effective connectivity based on EEG data during the resting-state and P50 tasks. Subjects demonstrated reduced P50 suppression and prolonged PVT reaction time after TSD compared with RW. Effective connectivity analysis of resting-state EEG data showed that sleep deprivation decreased the connectivity from the right middle occipital gyrus (RMOG)/Rcuneus to left inferior/middle temporal gyrus (LITG/LMTG) and left parahippocampal/fusiform gyrus (LPH/LFG). EEG data analysis during the P50 task showed that, in addition to the aforementioned connectivity changes, the directed high-frequency effective connectivity from the left precuneus to the left superior/middle frontal gyrus (LSFG/LMFG), LITG/LMTG, LPH/LFG, and left middle occipital gyrus (LMOG)/Lcuneus increased. P50 suppression in Cz positively correlated with PVT reaction time. This study reveals that the precuneus is a key brain region in neural network correlates of sensory gating, and that changes in its effective connectivity with other regions (including LSFG/LMFG, LPH/LFG, LMOG/LCuneus, and LITG/LMTG) are important for decreasing sensory gating after TSD.

CPAP Adherence is Associated With Attentional Improvements in a Group of Primarily Male Patients With Moderate to Severe OSA.

Obstructive sleep apnea (OSA) is a widespread condition that adversely affects physical health and cognitive functioning. The prevailing treatment for OSA is continuous positive airway pressure (CPAP), but therapeutic benefits are dependent on consistent use. Our goal was to investigate the relationship between CPAP adherence and measures of sustained attention in patients with OSA. Our hypothesis was that the Psychomotor Vigilance Task (PVT) would be sensitive to attention-related improvements resulting from CPAP use. This study was a secondary analysis of a larger clinical trial. Treatment adherence was determined from CPAP use data. Validated sleep-related questionnaires and a sustained-attention and alertness test (PVT) were administered to participants at baseline and at the 6-month time point. Over a 6-month time period, the average CPAP adherence was 3.32 h/night (standard deviation [SD] = 2.53), average improvement in PVT minor lapses was -4.77 (SD = 13.2), and average improvement in PVT reaction time was -73.1 milliseconds (standard deviation = 211). Multiple linear regression analysis showed that higher CPAP adherence was significantly associated with a greater reduction in minor lapses in attention after 6 months of continuous treatment with CPAP therapy (β = -0.72, standard error = 0.34, P = .037). The results of this study showed that higher levels of CPAP adherence were associated with significant improvements in vigilance. Because the PVT is a performance-based measure that is not influenced by prior learning and is not subjective, it may be an important supplement to patient self-reported assessments. Name: Effect of Self-Management on Improving Sleep Apnea Outcomes, URL: https://clinicaltrials.gov/ct2/show/NCT00310310, Identifier: NCT00310310.

Selective neuronal lapses precede human cognitive lapses following sleep deprivation.

Sleep deprivation (SD) is a major source of morbidity with widespread health effects including increased risks of hypertension, diabetes, obesity, heart attack, and stroke1. Moreover, SD brings about vehicle accidents and medical errors2–4, and is therefore an urgent topic of investigation. During SD, homeostatic and circadian processes interact to build up sleep pressure5 that results in slow behavioral performance (cognitive lapses) typically attributed to attentional thalamic and fronto-parietal circuits6–14, but the underlying mechanisms remain unclear3,15. Recently, it was found in human electroencephalogram (EEG)16,17 and in the local field potential (LFP) of non-human primates18 and rodents19 that during SD, regional ‘sleep-like’ slow/theta waves co-occur with impaired behavioral performance during wakefulness. Here we used intracranial electrodes to record single-neuron and LFP activities in human neurosurgical patients performing a face/non-face categorization psychomotor vigilance task (PVT)20–24 in multiple experimental sessions, including after full-night SD. We find that just before cognitive lapses, selective spiking responses of individual neurons in the medial temporal lobe (MTL) are attenuated, delayed, and lengthened. These ‘neuronal lapses’ are evident on a trial-by-trial basis comparing the slowest behavioral PVT reaction times to the fastest. Furthermore, during cognitive lapses LFPs exhibit a relative local increase in slow/theta activity that is correlated with degraded single-neuron responses and with baseline theta activity. Our results show that cognitive lapses involve local state-dependent changes in neuronal activity already in the MTL.