Fatigue on the flight deck: the consequences of sleep loss and the benefits of napping

Sleep Inertia in Aviation

INTRODUCTION: Sleep inertia is the transition state during which alertness and cognitive performance are temporarily impaired after awakening. Magnitude and time course of sleep inertia are characterized by high individual variability with large differences between the cognitive functions affected. This period of impairment is of concern to pilots, who take sleep or nap periods during on-call work hours or in-flight rest, then need to perform safety-critical tasks soon after waking. This review analyzes literature related to sleep inertia and countermeasures applicable for aviation.METHODS: The large part of scientific literature that focuses on sleep inertia is based on studies in patients with chronic sleep inertia. We analyzed 8 narrative reviews and 64 papers related to acute sleep inertia in healthy subjects.DISCUSSION: Sleep inertia is a multifactorial, complex process, and many different protocols have been conducted, with a low number of subjects, in noncontrolled laboratory designs, with questionnaires or cognitive tests that have not been replicated. Evidence suggests that waking after sleep loss, or from deeper stages of sleep, can exacerbate sleep inertia through complex interactions between awakening and sleep-promoting brain structures. Nevertheless, no meta-analyses are possible and extrapolation to pilots' performances is hypothetical. Studies in real life or simulated operational situations must be conducted to improve the description of the impact of sleep inertia and kinetics on pilots' performances. Taking rest or sleep time remains the main method for pilots to fight against fatigue and related decreases in performance. We propose proactive strategies to mitigate sleep inertia and improve alertness.Sauvet F, Beauchamps V, Cabon P. Sleep inertia in aviation. Aerosp Med Hum Perform. 2024; 95(4):206-213.

Recovery of Cognitive Performance Following Multi-Stressor Military Training

OBJECTIVE

This project aimed to assess the impact of an 8-day military training exercise on cognitive performance, and track its recovery in periods of reduced training load and partially restored sleep.

BACKGROUND

Military personnel often work in challenging multi-stressor environments, where sleep loss is inevitable. Sleep loss can impair multiple cognitive domains, which can have disastrous consequences in military contexts.

METHOD

A total of 57 male and female soldiers undergoing the Australian Army combat engineer Initial Employment Training course were recruited and tracked over a 16-day study period which included an 8-day field-based military training exercise. Cognitive performance was assessed via a computerised battery at seven time points across four sequential study periods; 1) baseline (PRE), 2) military field training exercise which included total sleep deprivation (EX-FIELD), 3) training exercise at simulated base with restricted sleep opportunities (EX-BASE), and 4) a 3-day recovery period (REC). Subjective load, fatigue, and sleep were evaluated continuously via questionnaire and actigraphy.

RESULTS

Psychomotor speed, reaction time, visual tracking and vigilance were impaired following the EX-FIELD period (p < 0.05). The majority of affected measures recovered 2 days following EX-FIELD, being no different in EX-BASE compared to PRE.

CONCLUSION

The sensitivity of the cognitive tests to sleep restriction, and recovery, indicates they can help assess operational readiness in military personnel. Future studies should explore other indicators of, and strategies to preserve, operational readiness in military personnel.

APPLICATION

This study highlights the impact of work-induced fatigue on cognitive performance, and would interest authorities seeking to preserve operational readiness.

Steps toward developing a comprehensive fatigue monitoring and mitigation solution: perspectives from a cohort of United States Naval Surface Force officers

Study Objectives

This study analyzed fatigue and its management in US Naval Surface Force warships, focusing on understanding current practices and barriers, and examining the influence of organizational and individual factors on managing chronic fatigue. Furthermore, this study explored the impact of organizational and individual factors on fatigue management.

Methods

As part of a larger study, 154 naval officers (mean ± standard deviation; 31.5 ± 7.0 years; 8.8 ± 6.8 years of service; 125 male, and 29 female) completed a fatigue survey. The survey addressed (1) self-reported fatigue, (2) fatigue observed in others, (3) fatigue monitoring strategies, (4) fatigue mitigation strategies, and (5) barriers to fatigue mitigation. Logistic and ordinal regressions were performed to examine the effect of individual (i.e. sleep quality and years in military service) and organizational (i.e. ship-class) factors on fatigue outcomes.

Results

Fatigue was frequently experienced and observed by 23% and 54% of officers, respectively. Of note, officers often monitored fatigue reactively (i.e. 65% observed others nodding off and 55% observed behavioral impairments). Still, officers did not frequently implement fatigue mitigation strategies, citing few operationally feasible mitigation strategies (62.3%), being too busy (61.7%), and not having clear thresholds for action (48.7%). Fatigue management varies across organizational factors, which must be considered when further developing fatigue management strategies.

Conclusions

Fatigue remains a critical concern aboard surface force ships and it may be better addressed through development of objective sleep and fatigue monitoring tools that could inform leadership decision-making.

Lifestyle mediators of associations among siestas, obesity, and metabolic health

OBJECTIVE

The aim of this study was to determine the association between siestas/no siestas and obesity, considering siesta duration (long: >30 minutes, short: ≤30 minutes), and test whether siesta traits and/or lifestyle factors mediate the association of siestas with obesity and metabolic syndrome (MetS).

METHODS

This was a cross-sectional study of 3275 adults from a Mediterranean population (the Obesity, Nutrigenetics, TIming, and MEditerranean [ONTIME] study) who had the opportunity of taking siestas because it is culturally embedded.

RESULTS

Thirty-five percent of participants usually took siestas (16% long siestas). Compared with the no-siesta group, long siestas were associated with higher values of BMI, waist circumference, fasting glucose, systolic blood pressure, and diastolic blood pressure, as well as with a higher prevalence of MetS (41%; p = 0.015). In contrast, the probability of having elevated SBP was lower in the short-siesta group (21%; p = 0.044) than in the no-siesta group. Smoking a higher number of cigarettes per day mediated the association of long siestas with higher BMI (by 12%, percentage of association mediated by smoking; p < 0.05). Similarly, delays in nighttime sleep and eating schedules and higher energy intake at lunch (the meal preceding siestas) mediated the association between higher BMI and long siestas by 8%, 4%, and 5% (all p < 0.05). Napping in bed (vs. sofa/armchair) showed a trend to mediate the association between long siestas and higher SBP (by 6%; p = 0.055).

CONCLUSIONS

Siesta duration is relevant in obesity/MetS. Timing of nighttime sleep and eating, energy intake at lunch, cigarette smoking, and siesta location mediated this association.

Fatigue, Work Overload, and Sleepiness in a Sample of Spanish Commercial Airline Pilots

Commercial aviation pilots are an occupational group that work in particular conditions, with frequent schedule changes, shift work, unfavorable environmental conditions, etc. These circumstances can lead to fatigue, work overload (WO), and daytime sleepiness, factors that can affect their health and safety. This study aimed to assess the prevalence and the association between these parameters in a sample of Spanish commercial airline pilots. The Raw TLX, Fatigue Severity Scale, and the Epworth Sleepiness Scale questionnaires were administered in a sample of 283 participants. The relationships of the total scores between all the questionnaires were studied by the chi-square test and the risk scores (odds ratio) were calculated. Different models using multiple linear regression were carried out to evaluate the effects of WO, fatigue, and daytime sleepiness, among the total scores, age, and flight hours. Additionally, the internal consistency of each questionnaire was estimated. A total of 28.2% presented WO above the 75th percentile, with mental and temporal demand the dimensions with the greatest weight. A total of 18% of pilots presented fatigue, 15.8% moderate sleepiness, and 3.9% severe sleepiness. We observed an association among WO, fatigue, and daytime sleepiness, important factors related to pilot health and aviation safety.

Psychophysiological coherence training to moderate air traffic controllers' fatigue on rotating roster

The nature of the current rotating roster, providing 24-h air traffic services over five irregular shifts, leads to accumulated fatigue which impairs air traffic controllers' cognitive function and task performance. It is imperative to develop an effective fatigue risk management system to improve aviation safety based upon scientific approaches. Two empirical studies were conducted to address this issue. Study 1 investigated the mixed effect of circadian rhythm disorders and resource depletion on controllers' accumulated fatigue. Then, study 2 proposed a potential biofeedback solution of quick coherence technique which can mitigate air traffic controllers' (ATCOs') fatigue while on controller working position and improve ATCOs' mental/physical health. The current two-studies demonstrated a scientific approach to fatigue analysis and fatigue risk mitigation in the air traffic services domain. This research offers insights into the fluctuation of ATCO fatigue levels and the influence of a numbers of factors related to circadian rhythm and resource depletion impact on fatigue levels on study 1; and provides psychophysiological coherence training to increase ATCOs' fatigue resilience to mitigate negative impacts of fatigue on study 2. Based on these two studies, the authors recommended that an extra short break for air traffic controllers to permit practicing the quick coherence breathing technique for 5 min at the sixth working hour could substantially recharge cognitive resources and increase fatigue resilience. Application: Present studies highlight an effective fatigue intervention based on objective biofeedback to moderate controllers' accumulated fatigue as a result of rotating shift work. Accordingly, air navigation services providers and regulators can develop fatigue risk management systems based on scientific approaches to improve aviation safety and air traffic controller's wellbeing.

Combined effects of time-of-day and simulated military operational stress on perception-action coupling performance

Perception-action coupling, the ability to 'read and react' to the environment, is essential for military personnel to operate within complex and unpredictable environments. Exposure to military operational stressors (e.g., caloric restriction, sleep loss, physical exertion), including around-the-clock operations, may compromise perception-action coupling, thereby impacting performance and safety. We examined the combined effects of simulated military operational stress (SMOS) and time-of-day on perception-action coupling. Fifty-seven active duty and reservist military personnel (45 M; 26.4 ± 5.6 years) completed a 5-day SMOS protocol that included two consecutive days of caloric restriction, and sleep restriction, and disruption. Participants completed a tablet-based perception-action coupling task (PACT) that involves perceiving whether virtual balls fit through virtual apertures. Familiarization occurred on day 0. Eight trials across day 1 (18:00, 22:00), 2 (04:00, 18:00, 22:00) and 3 (04:00, 18:00, 22:00) were analyzed. Mixed models were run to examine the interactive and main effects of day, and time-of-day on PACT response speed and accuracy outcomes. PACT response speed and accuracy outcomes improved at 18:00 and 22:00, whereas performance at 04:00 deteriorated across days. Perception-action coupling performance was resilient to SMOS, except in the early morning when the circadian drive for sleep is high, and the effects of sleep loss are more prominent.

Listening to 15 Hz Binaural Beats Enhances the Connectivity of Functional Brain Networks in the Mental Fatigue State—An EEG Study

Introduction: It is clear that mental fatigue can have many negative impacts on individuals, such as impairing cognitive function or affecting performance. The aim of this study was to investigate the role of sound interventions in combating mental fatigue. Method: The subjects were assessed on various scales, a psychomotor vigilance task (PVT) task, and a 3 min resting-state electroencephalogram (EEG), followed by a 20 min mental fatigue–inducing task (Time Load Dual Back, TloadDback), during which subjects in different condition groups listened to either 15 Hz binaural beats, 40 Hz binaural beats, relaxing music, or a 240 Hz pure tone. After the mental fatigue–inducing task, subjects were again assessed on various scales, a PVT task, and a 3 min resting-state EEG. Results: After the fatigue-inducing task, there was no significant difference between the four groups on the scales or the PVT task performance. In TloadDback, the accuracy rate of the 40 Hz binaural beats group and the relaxing music group decreased in the middle stage of the task, while the 15 Hz binaural beats group and the 240 Hz pure tone group remained unchanged in all stages of the task. The EEG results showed that after fatigue inducement, the average path length of the 15 Hz binaural beats group decreased, and local efficiency showed an increasing tendency, indicating enhanced brain network connectivity. Meanwhile, the 240 Hz pure tone group showed enhanced functional connectivity, suggesting a state of mental fatigue in the group. Conclusions: The results of this study show that listening to 15 Hz binaural beats is a proven intervention for mental fatigue that can contribute to maintaining working memory function, enhancing brain topological structure, and alleviating the decline in brain function that occurs in a mentally fatigued state. As such, these results are of great scientific and practical value.

Understanding Factors Underlying Fatigue among Collegiate Aviation Pilots in the United States

An increase in evidence-based studies into the deleterious effects of fatigue on flight operations has been reported by key aviation groups globally. The collegiate aviation flight training environment has not been researched at the same level when compared to military and airline operations. College aged students are unique in the sense that they are tasked with classwork, studying, participation in student organizations, social activities, and often have part time jobs within and outside of the academic environment. These conditions may cause errors, incidents, accidents, poor academic performance, and undesirable health metrics. The purpose of this study was to understand fatigue as a multi-factorial dimension and to assess potential relationships among these factors using hypothesized measurement models. The research team distributed the Collegiate Aviation Fatigue Inventory II (CAFI-II) to eight small, medium, and large collegiate aviation programs in the United States. The CAFI-II primarily focuses on fatigue awareness, causes and symptoms of fatigue, and lifestyle choices. Four hundred and twenty-two (n = 422) valid responses were obtained. Results suggested a direct predictive relationship between fatigue in collegiate flight training and the perceptions of respondents of conditions that are known to cause fatigue. Findings also suggested that respondents who had a favorable perception of fatigue risk and management programs had a better understanding of the causes of fatigue.

Study on Fatigue Coefficient of Airline Pilots

This paper uses the Multidimensional Fatigue Inventory (MFI-16) to investigate the fatigue status of pilots, and the reliability and validity of the scale are tested by Cronbach’s α and exploratory factor analysis. The founding shows that mild fatigue and above accounted for 67.7%. For further quantify the impact of different flights on pilots’ fatigue, research improves the fatigue coefficient model based on the results of pilot fatigue feeling questionnaire. Combined with multifactor analysis of variance and multiple linear regression, it is found that the independent variables have different and positive effects on the dependent variables, and there is no multicollinearity. Through the actual test, its accuracy is improved by 16.7% compared with the original model.

Short and Long Haul Pilots Rosters, Stress, Sleep Problems, Fatigue, Mental Health, and Well-Being

OBJECTIVE: This research was conducted to compare short haul (SH) and long haul (LH) pilots regarding sleep restrictions and fatigue risks on flight duty, stress, sleep problems, fatigue severity, well-being, and mental health. METHOD: There were 406 international SH and LH pilots who completed the cross-sectional online survey. Pilots sleep restrictions and fatigue-risk profiles (e.g., time pressure, late arrivals, minimum rest), sleep problems, fatigue severity, well-being, and symptoms of depression, anxiety, and common mental disorders (CMD) were measured and compared for SH and LH pilots. RESULTS: Although SH and LH pilots were scheduled for only 51.465.4% of the legally allowed duty and flight hours, 44.8% of SH pilots reported severe fatigue (FSS 4 to 4.9), and an additional 31.7% high fatigue (FSS 5), compared with 34.7% and 37.3% LH pilots. Considerable sleep problems in 8 nights/mo were reported by 24.6% SH vs. 23.5% LH pilots. Positive depression screenings were reported by 18.1% SH and 19.3% LH pilots. Positive anxiety screenings were reported by 9.6% SH and 5% LH pilots. Of all investigated pilots, 20% reported significant symptoms of depression or anxiety, and 7.23% had positive depression and anxiety screenings. LH pilots reported significantly better well-being than SH pilots. CONCLUSIONS: Our results show that even far less duty and flight hours than legally allowed according to flight time limitations lead to high levels of fatigue, sleep problems, and significant mental health issues among pilots. SH pilots were even more affected than LH pilots. Pilots fatigue should be considered an immediate threat to aviation safety and pilots fitness to fly by promoting fatigue and burnout. Venus M, grosse Holtforth M. Short and long haul pilots rosters, stress, sleep problems, fatigue, mental health, and well-being. Aerosp Med Hum Perform. 2021; 92(10):786797.

Fatigue in Aviation: Safety Risks, Preventive Strategies and Pharmacological Interventions

Fatigue poses an important safety risk to civil and military aviation. In addition to decreasing performance in-flight (chronic) fatigue has negative long-term health effects. Possible causes of fatigue include sleep loss, extended time awake, circadian phase irregularities and work load. Despite regulations limiting flight time and enabling optimal rostering, fatigue cannot be prevented completely. Especially in military operations, where limits may be extended due to operational necessities, it is impossible to rely solely on regulations to prevent fatigue. Fatigue management, consisting of preventive strategies and operational countermeasures, such as pre-flight naps and pharmaceuticals that either promote adequate sleep (hypnotics or chronobiotics) or enhance performance (stimulants), may be required to mitigate fatigue in challenging (military) aviation operations. This review describes the pathophysiology, epidemiology and effects of fatigue and its impact on aviation, as well as several aspects of fatigue management and recommendations for future research in this field.

Pilot Sleep Behavior across Time during Ultra-Long-Range Flights

Fatigue risk to the pilot has been a deterrent for conducting direct flights longer than 12 h under normal conditions, but such flights were a necessity during the COVID-19 pandemic. Twenty (N = 20) pilots flying across five humanitarian missions between Brazil and China wore a sleep-tracking device (the Zulu watch), which has been validated for the estimation of sleep timing (sleep onset and offset), duration, efficiency, and sleep score (wake, interrupted, light, or deep Sleep) throughout the mission period. Pilots also reported sleep timing, duration, and subjective quality of their in-flight rest periods using a sleep diary. To our knowledge, this is the first report of commercial pilot sleep behavior during ultra-long-range operations under COVID-19 pandemic conditions. Moreover, these analyses provide an estimate of sleep score during in-flight sleep, which has not been reported previously in the literature.

A trait of mind: stability and robustness of sleep across sleep opportunity manipulations during simulated military operational stress

STUDY OBJECTIVES

Within-subject stability of certain sleep features across multiple nights is thought to reflect the trait-like behavior of sleep. However, to be considered a trait, a parameter must be both stable and robust. Here, we examined the stability (i.e., across the same sleep opportunity periods) and robustness (i.e., across sleep opportunity periods that varied in duration and timing) of different sleep parameters.

METHODS

Sixty-eight military personnel (14 W) spent 5 nights in the sleep laboratory during a simulated military operational stress protocol. After an adaptation night, participants had an 8-hour sleep opportunity (23:00-07:00) followed by 2 consecutive nights of sleep restriction and disruption which included two 2-hour sleep opportunities (01:00-03:00; 05:00-07:00) and, lastly, another 8-hour sleep opportunity (23:00-07:00). Intra-class correlation coefficients were calculated to examine differences in stability and robustness across different sleep parameters.

RESULTS

Sleep architecture parameters were less stable and robust than absolute and relative spectral activity parameters. Further, relative spectral activity parameters were less robust than absolute spectral activity. Absolute alpha and sigma activity demonstrated the highest levels of stability that were also robust across sleep opportunities of varying duration and timing.

CONCLUSIONS

Stability and robustness varied across different sleep parameters, but absolute NREM alpha and sigma activity demonstrated robust trait-like behavior across variable sleep opportunities. Reduced stability of other sleep architecture and spectral parameters during shorter sleep episodes as well as across different sleep opportunities has important implications for study design and interpretation.

The Analysis of Occurrences Associated with Air Traffic Volume and Air Traffic Controllers' Alertness for Fatigue Risk Management

Fatigue is an inevitable hazard in the provision of air traffic services and it has the potential to degrade human performance leading to occurrences. The International Civil Aviation Organization (ICAO) requires air navigation services which providers establish fatigue risk management systems (FRMS) based on scientific principles for the purpose of managing fatigue. To develop effective FRMSs, it is important to investigate the relationship between traffic volume, air traffic management occurrences, and fatigue. Fifty-seven qualified ATCOs from a European Air Navigation Services provider participated in this research by providing data indicating their alertness levels over the course of a 24-hour period. ATCOs' fatigue data were compared against the total of 153 occurrences and 962,328 air traffic volumes from the Eurocontrol TOKAI incident database in 2019. The result demonstrated that ATCO fatigue levels are not the main contributory factor associated with air traffic management occurrences, although fatigue did impact ATCOs' performance. High traffic volume increases ATCO cognitive task load that can surpass available attention resources leading to occurrences. Furthermore, human resilience drives ATCOs to maintain operational safety though they suffer from circadian fatigue. Consequently, FRMS appropriately implemented can be used to mitigate the effects of fatigue. First-line countermeasure strategies should focus on enough rest breaks and roster schedule optimization; secondary strategies should focus on monitoring ATCOs' task loads that may induce fatigue. It is vital to consider traffic volume and ATCOs' alertness levels when implementing effective fatigue risk management protocols.

Acute and cumulative effects of scheduling on aircrew fatigue in ultra-short-haul operations

Aircrew fatigue constitutes a safety hazard in aviation, which authorities attempt to mitigate through flight time limitations. Some gaps in knowledge exist, however. The purpose of the present study was to investigate the associations of schedule characteristics with fatigue and amount of sleep in the acute 24-h window, and as cumulative effects across the 7-day work period. One hundred and six aircrew (14% cabin crew) participated. They rated fatigue on the Karolinska Sleepiness Scale (KSS) three times per flight day for four 7-day work periods, with up to 7 days off between work periods. Mixed model regression was applied to the data. In the multivariable model, more sleep was associated with lower fatigue (p = .000)), corresponding to 0.26 KSS units less per hour of sleep. Very early, early and late duty types, as well as duty time, were associated with higher fatigue. For the 7-day work period, accumulation of very early duties and longer duty time were associated with increased fatigue, and more accumulated sleep was associated with lower fatigue in the adjusted model (0.08 KSS units per hour of sleep) (p = .000). Accumulated duty time was not significant when analysed as a single variable, but became so after adjustment for sleep. The results suggest that sleep, duty time and early starts are important predictors of fatigue in the 24-h window and that the number of very early starts and short sleep have cumulative effects on fatigue across a 7-day work period.

Is insomnia disorder associated with time in bed extension?

Objective

There is a lack of evidence for extension of time in bed behaviors (i.e., getting to bed earlier, going out of bed later, staying in bed while awake and napping) as perpetuating factors of insomnia. The aim of this study is to assess if insomnia disorder is associated with extension of time in bed behaviors.

Methods

150 good sleepers and 173 insomniacs were recruited between December 2017 and June 2018. A cross-sectional survey was performed using the Wang Insomnia Integrated Questionnaire.

Results

Bedtime, rising time and time in bed were not different between good sleepers and insomniacs (Cohen’s d, <0.01, 0.07, 0.07, respectively; all p>0.05) and were not correlated with insomnia severity (all p>0.05). Staying in bed while awake during the night and in the morning where both different between good sleepers and insomniacs (Cohen’s d, 1.33 and 0.85, respectively; all p<0.001) and were positively correlated with insomnia severity (all p<0.001). Napping was more frequent (p<0.01) among good sleepers (63.3%) than insomniacs (48.6%) and a predictor of good sleep (p<0.01).

Conclusion

Going to bed earlier and getting out of bed later do not seem to be associated with insomnia. Staying in bed while awake during the night and in the morning are associated with insomnia but could be only signs of insomnia symptoms. Limiting time in bed to prevent insomnia might and suppressing insomniacs’ napping behavior to treat insomnia might not be effective.

Genetic determinants of daytime napping and effects on cardiometabolic health

Daytime napping is a common, heritable behavior, but its genetic basis and causal relationship with cardiometabolic health remain unclear. Here, we perform a genome-wide association study of self-reported daytime napping in the UK Biobank (n = 452,633) and identify 123 loci of which 61 replicate in the 23andMe research cohort (n = 541,333). Findings include missense variants in established drug targets for sleep disorders (HCRTR1, HCRTR2), genes with roles in arousal (TRPC6, PNOC), and genes suggesting an obesity-hypersomnolence pathway (PNOC, PATJ). Association signals are concordant with accelerometer-measured daytime inactivity duration and 33 loci colocalize with loci for other sleep phenotypes. Cluster analysis identifies three distinct clusters of nap-promoting mechanisms with heterogeneous associations with cardiometabolic outcomes. Mendelian randomization shows potential causal links between more frequent daytime napping and higher blood pressure and waist circumference.

Sleep inertia in automated driving: Post-sleep take-over and driving performance

Sleep is emerging as a new driver state in automated driving. Post-sleep performance impairments due to sleep inertia, the transitional phase from sleep to wakefulness that can take up to 30 min, are a potential safety issue. Take-over performance immediately after sleep is impaired and drivers perceive the take-over as critical. The aim of the presented study was to assess take-over behavior immediately after sleep and driving behavior during the 10 min after sleep. A study with N = 31 drivers was conducted in a high-fidelity driving simulator. Take-over performance and driving performance were assessed a) under alert baseline conditions and b) after awakening from electroencephalography-confirmed stable sleep. Take-over performance 15 s after awakening was impaired resulting in more driving errors compared to the alert baseline. Lane keeping was dramatically impaired in the first 3 min after sleep and recovered rapidly. Drivers drove slower after sleep and speed keeping was less stable for at least 10 min. The results suggest that human-machine interaction design should account for the drivers' impaired post-sleep driving performance.

Alarm Tones, Voice Warnings, and Musical Treatments: A Systematic Review of Auditory Countermeasures for Sleep Inertia in Abrupt and Casual Awakenings

Sleep inertia is a measurable decline in cognition some people experience upon and following awakening. However, a systematic review of the current up to date evidence of audio as a countermeasure has yet to be reported. Thus, to amend this gap in knowledge, the authors conducted this systematic review beginning with searches in three primary databases for studies published between the inception date of each journal and the year 2020. Search terms contained “Sleep Inertia” paired with: “Sound”; “Noise”; “Music”; “Alarm”; “Alarm Tone”; “Alarm Sound”; “Alarm Noise”; “Alarm Music”; “Alarm Clock”; “Fire Alarm”, and “Smoke Alarm”. From 341 study results, twelve were identified for inclusion against a priori conditions. A structured narrative synthesis approach generated three key auditory stimulus themes-(i) Noise, (ii) Emergency tone sequences; Voice Alarms and Hybrids, and (iii) Music. Across themes, participants have been assessed in two situational categories: emergency, and non-emergency awakenings. The results indicate that for children awakening in emergency conditions, a low pitch alarm or voice warnings appear to be more effective in counteracting the effects of sleep inertia than alarms with higher frequencies. For adults abruptly awakened, there is insufficient evidence to support firm conclusions regarding alarm types and voice signals. Positive results have been found in non-emergency awakenings for musical treatments in adults who preferred popular music, and alarms with melodic qualities. The results observed reflect the potential for sound, voice, and musical treatments to counteract sleep inertia post-awakening, and emphasize the requirements for further research in this domain.

Sleep in highly automated driving: Takeover performance after waking up

Takeover performance in automated driving is subject to investigation in the context of a variety of driver states such as distraction or drowsiness. New driver states will emerge with increasing automation level with drivers potentially being allowed to sleep while driving a highly automated vehicle. Still at some point during a drive, drivers will be required to or voluntarily take back control of the vehicle. A simulator study was conducted to investigate drivers' ability to take over the vehicle control after sleeping. In a within-subjects study design N = 25 test drivers completed a drive using a highly automated driving system a) during day time after a full night of sleep and b) early in the morning after a night of partial sleep deprivation. During the second drive, sleep was measured in drivers according to the American Academy of Sleep Medicine (AASM) standard using electroencephalography (EEG). In total, the participants had to handle four takeover requests (TORs) from the system, two while being awake (day drive) and two when being awakened from sleep stage N2 (morning drive). The objective criticality of the situations was assessed performing the Takeover Controllability rating (TOC-rating). The results indicate that the applied takeover time of 60 s was sufficient for drivers to reengage in driving after sleeping. Reaction times were extended by about 3 s after sleep compared to the wake condition. Takeover performance assessed with the TOC-rating however was clearly worse after sleep than after wakefulness which was also reflected in the drivers' subjective perception of the criticality of the situation. Further research is needed on how to deal with performance impairments after waking up from sleep during automated driving.

Mitigating fatigue on the flight deck: how is controlled rest used in practice?

Controlled Rest (CR) refers to a short, unscheduled, voluntary nap opportunity taken by pilots on the flight deck as a countermeasure to unanticipated fatigue in flight. This study explores the profile of CR use in a long-haul commercial airline. Forty-four pilots wore actiwatches and filled in an application-based sleep/work diary for approximately 2 weeks resulting in complete records from 239 flights. Timing of sleep periods and flight schedules were analyzed relative to home-base time. Pearson correlations were used to assess the influence of pilot demographics on CR use. A mixed-effects logistic regression was used to analyze the impact of schedule factors on CR. CR was taken on 46% (n = 110) of flights, with 80% (n = 106/133) of all CR attempts (accounting for multiple CR attempts on 23 flights) estimated by actigraphy to have successfully achieved sleep. Average sleep duration during successful rest periods was estimated as 31.7 ± 12.2 min. CR was more frequent on 2-pilot (69%, n = 83) vs. >2-pilot flights (23%, n = 27); return (60%, n = 71) vs. outbound flights (33%, n = 39); night (55%, n = 76) vs. day flights (34%, n = 34); and <10 h (63%, n = 80) vs. >10 h duration flights (27%, n = 30) (all p ≤ 0.001). There was no significant difference for direction of travel (eastbound: 51%, n = 57; westbound: 40%, n = 44; p = .059). Of note, 22% (n = 26) of augmented flights contained both CR and bunk rest. Data from this airline show that CR is most commonly used on flights with 2-pilot crews (<10 h duration) and nighttime flights returning to base. Future studies are required to determine the generalizability of these results to other airlines.

Midday napping in children: associations between nap frequency and duration across cognitive, positive psychological well-being, behavioral, and metabolic health outcomes

STUDY OBJECTIVES

Poor sleep and daytime sleepiness in children and adolescents have short- and long-term consequences on various aspects of health. Midday napping may be a useful strategy to reduce such negative impacts. The effect of habitual napping on a wide spectrum of cognitive, behavioral, psychological, and metabolic outcomes has not been systematically investigated.

METHODS

This study characterized midday napping habits in 3819 elementary school children from the China Jintan Cohort Study. In 2011, weekly nap frequency and average duration were collected once from students at grades 4-6. Prior to their completion of elementary school at grade 6 (in 2011-2013 respective to each grade), the following outcomes were collected once: behavioral and academic achievement evaluated by teachers, and self-reported positive psychology measures including grit, self-control, and happiness. IQ tests were conducted on a subgroup. Metabolic indices, including body mass index and fasting glucose concentration, were measured through physical exams. For the whole sample, we assessed associations between napping and each outcome, adjusted for sex, grade, school location, parental education, and time in bed at night. We also conducted stratified analyses on grade 6 (cross-sectional), grade 4 (2-year gap), and grade 5 (1-year gap) data.

RESULTS

Overall, napping was significantly associated with higher happiness, grit, and self-control, reduced internalizing behavior problem, higher verbal IQs, and better academic achievement, although specific patterns varied across frequency and duration for different outcomes. More limited significant associations were found for decreased externalizing behavior problems, compared to non-nappers, while no significant associations were found for performance IQ and metabolic outcomes.

CONCLUSIONS

Results indicate benefits of regular napping across a wide range of adolescent outcomes, including better cognition, better psychological wellness, and reduced emotional/behavioral problems. The current study underscores the need for further large-scale intervention studies to establish causal effects.

The Crossroads of Posttraumatic Stress Disorder and Physician Burnout: A National Review of United States Trauma and Nontrauma Surgeons

Posttraumatic stress disorder (PTSD) among trauma surgeons is three times that of the general population, and physician burnout (PBO) among surgeons is rising. Given that PTSD and PBO are both stress-based syndromes, we aim to identify the prevalence and risk factors for PTSD among trauma and nontrauma surgeons, and determine if a relationship exists. A cross-sectional survey of surgeons was conducted between September 2016 and May 2017. Respondents were screened for PTSD and PBO. Traumatic stressors were identified, and 20 potential risk factors were assessed. The respondents (n = 1026) were grouped into trauma (n = 350) and nontrauma (n = 676). Between the cohorts, there was no significant difference in prevalence of screening positive for PTSD (17% vs 15%) or PBO (30% vs 25%). A relationship was found between PTSD and PBO (P < 0.001). The most common traumatic stressor was overwhelming work responsibilities. Potential risk factors for PTSD differed, but overlapping risk factors included hospital culture, hospital support, and salary (P < 0.05). Our findings of an association between PTSD and PBO is concerning. Interventions to reduce rates of PTSD should target changing the existing culture of surgery, improving hospital support, and ensuring equitable pay.

Causes and Management of Sleepiness Among Pilots in a Norwegian and an Austrian Air Ambulance Service-A Comparative Study

OBJECTIVE

We compared subjectively reported sleepiness and fatigue as well as causes and management strategies for combating sleepiness among pilots working in 2 different helicopter emergency medical services operating with different shift systems.

METHODS

Pilots from the Norwegian Air Ambulance (NAA) and Christophorus Flugrettungsverein (CFV) in Austria participated. NAA performs flight missions 24/7, whereas at the time of the study the participating CFV bases did not fly after sunset. The pilots are on duty for 1 week in both services. NAA and CFV used an identical research protocol, including questionnaires about sleep, sleepiness (Epworth Sleepiness Scale and Karolinska Sleepiness Scale), coping strategies, and work-related causes of fatigue.

RESULTS

CFV pilots kept busy, whereas NAA pilots slept and did physical exercise as strategies to prevent sleepiness. The majority in both groups used napping and coffee consumption as strategies. CFV pilots reported more frequently than NAA pilots that administrative duties and environmental factors were reasons preventing napping.

CONCLUSION

Some differences existed between the 2 pilot groups regarding strategies for managing sleepiness and causes that prevented pilots from napping. Pilots in both groups were healthy, physically active, and had normal Epworth Sleepiness Scale and Karolinska Sleepiness Scale scores.

Fast Convolutional Method for Automatic Sleep Stage Classification

Objectives

Polysomnography is essential to diagnose sleep disorders. It is used to identify a patient's sleep pattern during sleep. This pattern is obtained by a doctor or health practitioner by using a scoring process, which is time consuming. To overcome this problem, we developed a system that can automatically classify sleep stages.

Methods

This paper proposes a new method for sleep stage classification, called the fast convolutional method. The proposed method was evaluated against two sleep datasets. The first dataset was obtained from physionet.org, a physiologic signals data centers. Twenty-five patients who had a sleep disorder participated in this data collection. The second dataset was collected in Mitra Keluarga Kemayoran Hospital, Indonesia. Data was recorded from ten healthy respondents.

Results

The proposed method reached 73.50% and 56.32% of the F-measures for the PhysioNet and Mitra Keluarga Kemayoran Hospital data, respectively. Both values were the highest among all the machine learning methods considered in this study. The proposed method also had an efficient running time. The fast convolutional models of the PhysioNet and Mitra Keluarga Kemayoran Hospital data needed 42.60 and 0.06 seconds, respectively.

Conclusions

The fast convolutional method worked well on the tested datasets. It achieved a high F-measure result and an efficient running time. Thus, it can be considered a promising tool for sleep stage classification.

Use of Actigraphy for the Evaluation of Sleep Disorders and Circadian Rhythm Sleep-Wake Disorders: An American Academy of Sleep Medicine Systematic Review, Meta-Analysis, and GRADE Assessment

INTRODUCTION

The purpose of this systematic review is to provide supporting evidence for a clinical practice guideline on the use of actigraphy.

METHODS

The American Academy of Sleep Medicine commissioned a task force of experts in sleep medicine. A systematic review was conducted to identify studies that compared the use of actigraphy, sleep logs, and/or polysomnography. Statistical analyses were performed to determine the clinical significance of using actigraphy as an objective measure of sleep and circadian parameters. Finally, the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) process was used to assess the evidence for making recommendations.

RESULTS

The literature search resulted in 81 studies that met inclusion criteria; all 81 studies provided data suitable for statistical analyses. These data demonstrate that actigraphy provides consistent objective data that is often unique from patient-reported sleep logs for some sleep parameters in adult and pediatric patients with suspected or diagnosed insomnia, circadian rhythm sleep-wake disorders, sleep-disordered breathing, central disorders of hypersomnolence, and adults with insufficient sleep syndrome. These data also demonstrate that actigraphy is not a reliable measure of periodic limb movements in adult and pediatric patients. The task force provided a detailed summary of the evidence along with the quality of evidence, the balance of benefits and harms, patient values and preferences, and resource use considerations.

Examining courses of sleep quality and sleepiness in full 2 weeks on/2 weeks off offshore day shift rotations

To better understand sleep quality and sleepiness problems offshore, we examined courses of sleep quality and sleepiness in full 2-weeks on/2-weeks off offshore day shift rotations by comparing pre-offshore (1 week), offshore (2 weeks) and post-offshore (1 week) work periods. A longitudinal observational study was conducted among N=42 offshore workers. Sleep quality was measured subjectively with two daily questions and objectively with actigraphy, measuring: time in bed (TIB), total sleep time (TST), sleep latency (SL) and sleep efficiency percentage (SE%). Sleepiness was measured twice a day (morning and evening) with the Karolinska Sleepiness Scale. Changes in sleep and sleepiness parameters during the pre/post and offshore work periods were investigated using (generalized) linear mixed models. In the pre-offshore work period, courses of SE% significantly decreased (p=.038). During offshore work periods, the courses of evening sleepiness scores significantly increased (p<.001) and significantly decreased during post-offshore work periods (p=.004). During offshore work periods, TIB (p<.001) and TST (p<.001) were significantly shorter, SE% was significantly higher (p=.002), perceived sleep quality was significantly lower (p<.001) and level of rest after wake was significantly worse (p<.001) than during the pre- and post-offshore work periods. Morning sleepiness was significantly higher during offshore work periods (p=.015) and evening sleepiness was significantly higher in the post-offshore work period (p=.005) compared to the other periods. No significant changes in SL were observed. Courses of sleep quality and sleepiness parameters significantly changed during full 2-weeks on/2-weeks off offshore day shift rotation periods. These changes should be considered in offshore fatigue risk management programmes.

An Overview of the Clinical Uses, Pharmacology, and Safety of Modafinil

Modafinil (MOD) is a wakefulness-inducing compound prescribed for treatment of excessive daytime sleepiness as a consequence of sleep disturbances such as shift work sleep disorder, obstructive sleep apnea, restless leg syndrome, or narcolepsy. While providing effective results in patients with sleepiness, MOD also produces positive outcomes in the management of fatigue associated with different conditions including depression, cancer, or tiredness in military personnel. Although there is clear evidence of the stimulant effects of MOD, current data also show that administration of this drug apparently induces positive neurobiological effects, such as improvement in memory. However, serious concerns have been raised since some reports have suggested MOD dependence. Taken together, these findings highlight the need to characterize the changes induced by MOD which have been observed in several neurobiological functions. Moreover, further work should follow up on the likely long-term effects of this drug if used for treatment of drowsiness and tiredness. Here, we review and summarize recent findings of the medical uses of MOD in the management of sleepiness and fatigue associated with depression or cancer as well as exhaustion in military personnel. We also discuss the available literature related with the cognitive enhancing properties of this stimulant, as well as what is known and unknown about MOD addiction.

Night work and BMI: is it related to on-shift napping?

On-shift napping can benefit night workers regarding sleep loss, synchronization of circadian rhythms, and alertness. However, few studies on napping can be found in the literature focused on possible health benefits. This cross-sectional study has investigated the role of on-shift napping on the association between night work and BMI in 409 night-shift nursing professionals. The number of working nights and the years of exposure to night work were significantly associated with increased BMI levels among non-nappers, but not among nappers. Results suggest a benefit of napping for weight gain, thus subsidizing occupational health policies on the regulation of on-shift napping among nursing workers.

Reduced Stress and Improved Sleep Quality Caused by Green Tea Are Associated with a Reduced Caffeine Content

Caffeine, one of the main components in green tea, can interfere with sleep and block the effect of theanine. Since theanine, the main amino acid in tea leaves, has significant anti-stress effects in animals and humans, we examined the effects of green tea with lowered caffeine content, i.e., low-caffeine green tea (LCGT), on stress and quality of sleep of middle-aged individuals (n = 20, mean age 51.3 ± 6.7 years) in a double-blind crossover design. Standard green tea (SGT) was used as the control. These teas (≥300 mL/day), which were eluted with room temperature water, were consumed over a period of seven days after a single washout term. The level of salivary α-amylase activity (sAA), a stress marker, was significantly lower in participants that consumed LCGT (64.7 U/mL) than in those that consumed SGT (73.9 U/mL). Sleep quality was higher in participants that consumed a larger quantity of LCGT. In addition, a self-diagnostic check for accumulated fatigue was significantly lower in those participants that consumed LCGT than SGT. These results indicate that LCGT intake can reduce stress in middle-aged individuals and improve their quality of sleep. The reduction in caffeine is suggested to be a valid reason for enhancing the anti-stress effect of green tea.

Reduced Stress and Improved Sleep Quality Caused by Green Tea Are Associated with a Reduced Caffeine Content

Caffeine, one of the main components in green tea, can interfere with sleep and block the effect of theanine. Since theanine, the main amino acid in tea leaves, has significant anti-stress effects in animals and humans, we examined the effects of green tea with lowered caffeine content, i.e., low-caffeine green tea (LCGT), on stress and quality of sleep of middle–aged individuals (n = 20, mean age 51.3 ± 6.7 years) in a double-blind crossover design. Standard green tea (SGT) was used as the control. These teas (≥300 mL/day), which were eluted with room temperature water, were consumed over a period of seven days after a single washout term. The level of salivary α-amylase activity (sAA), a stress marker, was significantly lower in participants that consumed LCGT (64.7 U/mL) than in those that consumed SGT (73.9 U/mL). Sleep quality was higher in participants that consumed a larger quantity of LCGT. In addition, a self-diagnostic check for accumulated fatigue was significantly lower in those participants that consumed LCGT than SGT. These results indicate that LCGT intake can reduce stress in middle-aged individuals and improve their quality of sleep. The reduction in caffeine is suggested to be a valid reason for enhancing the anti-stress effect of green tea.

Sleep, alertness and alertness management among commercial airline pilots on short-haul and long-haul flights

Airline pilots' sleep and on-duty alertness are important focus areas in commercial aviation. Until now, studies pertaining to this topic have mainly focused on specific characteristics of flights and thus a comprehensive picture of the matter is not well established. In addition, research knowledge of what airline pilots actually do to maintain their alertness while being on duty is scarce. To address these gaps in research knowledge, we conducted a field study on a representative sample of the airline pilots of a medium-sized airline. The sample consisted of 90 pilots, of whom 30 flew long-haul (LH) routes, 30 short-haul (SH) routes, and 30 flew both. A total of 86 pilots completed the measurements that lasted for almost two months per pilot. The measurements resulted in a total of 965 flight duty periods (FDPs) including SH flights and 627 FDPs including LH flights. During the measurement periods, sleep was measured by a diary and actigraphs, on-duty alertness by the Karolinska Sleepiness Scale (KSS) in all flight phases, and on-duty alertness management strategies by the diary. Results showed that SH and LH FDPs covering the whole domicile night (00:00-06:00 at home base) were most consistently associated with reduced sleep-wake ratio and subjective alertness. Approximately every 3rd FDP falling into this category involved a reduced sleep-wake ratio (1:3 or lower) and every 2nd a reduced level of subjective alertness (KSS rating 8-9 in at least one flight phase). The corresponding frequencies for the SH and LH FDPs that partly covered the domicile night were every 10th and every 5th FDP and for the pure non-night FDPs every 30th and every 36th FDP, respectively. The results also showed that the pilots tended to increase the use of effective on-duty alertness management strategies (consuming alertness-promoting products and taking strategic naps) in connection with the FDPs that overlapped the domicile night. Finally, the results showed that the frequency of flights involving reduced subjective alertness depended on how alertness was assessed. If it was assessed solely in the flight phase just before starting the landing procedures (top of descent) the phenomenon was less frequent than if the preceding cruise phase was also taken into account. Our results suggest that FDPs covering the whole domicile night should be prioritised over the other FDPs in fatigue management, regardless of whether an FDP is a short-haul or a long-haul. In addition, the identification of fatigue in flight operations requires one to assess pilots' alertness across all flight phases, not only at ToD. Due to limitations in our data, these conclusions can, however, be generalise to only LH FDPs during which pilots can be expected to be well acclimatised to the local time at their home base and SH night FDPs that include at least 3h of flying in the cruise phase.

Neuroimaging of Central Sensitivity Syndromes: Key Insights from the Scientific Literature

Central sensitivity syndromes are characterized by distressing symptoms, such as pain and fatigue, in the absence of clinically obvious pathology. The scientific underpinnings of these disorders are not currently known. Modern neuroimaging techniques promise new insights into mechanisms mediating these postulated syndromes. We review the results of neuroimaging applied to five central sensitivity syndromes: fibromyalgia, chronic fatigue syndrome, irritable bowel syndrome, temporomandibular joint disorder, and vulvodynia syndrome. Neuroimaging studies of basal metabolism, anatomic constitution, molecular constituents, evoked neural activity, and treatment effect are compared across all of these syndromes. Evoked sensory paradigms reveal sensory augmentation to both painful and nonpainful stimulation. This is a transformative observation for these syndromes, which were historically considered to be completely of hysterical or feigned in origin. However, whether sensory augmentation represents the cause of these syndromes, a predisposing factor, an endophenotype, or an epiphenomenon cannot be discerned from the current literature. Further, the result from cross-sectional neuroimaging studies of basal activity, anatomy, and molecular constituency are extremely heterogeneous within and between the syndromes. A defining neuroimaging "signature" cannot be discerned for any of the particular syndromes or for an over-arching central sensitization mechanism common to all of the syndromes. Several issues confound initial attempts to meaningfully measure treatment effects in these syndromes. At this time, the existence of "central sensitivity syndromes" is based more soundly on clinical and epidemiological evidence. A coherent picture of a "central sensitization" mechanism that bridges across all of these syndromes does not emerge from the existing scientific evidence.

The effects of napping on the risk of hypertension: a systematic review and meta-analysis

OBJECTIVE

The risk of hypertension in adults who regularly take a nap is controversial. The objective of this meta-analysis was to assess the associations between napping and hypertension.

METHODS

A literature search was performed using MEDLINE, EMbase and The Cochrane Database of Systematic Reviews from inception through October, 2015. Studies that reported relative risks, odd ratios or hazard ratios comparing the risk of hypertension in individuals who regularly take nap were included. Pooled risk ratios (RR) and 95% confidence interval (CI) were calculated using a random-effect, generic inverse variance method.

RESULTS

Nine observational studies with 112,267 individuals were included in the analysis to assess the risk of hypertension in nappers. The pooled RR of hypertension in nappers was 1.13 with 95% CI (0.98 to 1.30). When meta-analysis was limited only to studies assessing the risk of hypertension in daytime nappers, the pooled RR of hypertension was 1.19 with 95% CI (1.06 to 1.35). The data on association between nighttime napping in individuals who work night shift and hypertension were limited, only one observational study reported reduced risk of hypertension in nighttime nappers with odds ratio of 0.79 with 95% CI (0.63 to 1.00).

CONCLUSIONS

Our meta-analysis demonstrates a significant association between daytime napping and hypertension. Future study is needed to assess the potential benefits of HTN screening for daytime nappers.

Determinants of seafarers' fatigue: a systematic review and quality assessment

PURPOSE

Fatigue jeopardizes seafarer's health and safety. Thus, knowledge on determinants of fatigue is of great importance to facilitate its prevention. However, a systematic analysis and quality assessment of all empirical evidence specifically for fatigue are still lacking. The aim of the present article was therefore to systematically detect, analyze and assess the quality of this evidence.

METHODS

Systematic searches in ten databases were performed. Searches considered articles published in scholarly journals from 1980 to April 15, 2016. Nineteen out of 98 eligible studies were included in the review. The main reason for exclusion was fatigue not being the outcome variable.

RESULTS

Most evidence was available for work time-related factors suggesting that working nights was most fatiguing, that fatigue levels were higher toward the end of watch or shift, and that the 6-h on-6-h off watch system was the most fatiguing. Specific work demands and particularly the psychosocial work environment have received little attention, but preliminary evidence suggests that stress may be an important factor. A majority of 12 studies were evaluated as potentially having a high risk of bias.

CONCLUSIONS

Realistic countermeasures ought to be established, e.g., in terms of shared or split night shifts. As internal as well as external validity of many study findings was limited, the range of factors investigated was insufficient and few studies investigated more complex interactions between different factors, knowledge derived from studies of high methodological quality investigating different factors, including psychosocial work environments, are needed to support future preventive programs.

Human Performance Optimization: Culture Change and Paradigm Shift

The term "Human Performance Optimization" (HPO) emerged across the Department of Defense (DoD) around 2006 when the importance of human performance for military success on the battlefield was acknowledged. Likewise, the term Total Force Fitness (TFF) arose as a conceptual framework within DoD in response to the need for a more holistic approach to the unparalleled operational demands with multiple deployments and strains on the United States Armed Forces. Both HPO and TFF are frameworks for enhancing and sustaining the health, well-being, and performance among our warriors and their families; they are fundamental to accomplishing our nation's mission. A demands-resources model for HPO is presented within the context of TFF to assist in operationalizing actions to enhance performance. In addition, the role leaders can serve is discussed; leaders are uniquely postured in the military chain of command to directly influence a culture of fitness for a ready force, and promote the concept that service members are ultimately responsible for their fitness and performance.

Factors to affect improvement in cyber officer performance

Purpose

The purpose of this study is to investigate how motivation – gained by understanding the purpose of specific cyber-oriented tasks – coping strategies and level of physical conditioning can affect cognitive abilities amongst cyber officer cadets.

Design/methodology/approach

Two cognitive tests (2014 and 2015) and coping strategy questionnaires (2015) were conducted during an annual military exercise involving increased levels of stress and hardship (physical and cognitive) over a sustained two-week period.

Findings

Motivation – gained by task explanations – and the conscious use of the “control” strategy can have a positive effect on individual performance in cyber tasks.

Research limitations/implications

The participants were all young adults with higher-than-average levels of physical fitness. From the outset, all participants were highly motivated and disciplined having entered cyber officer training after successfully completing a thorough selection process.

Practical implications

The results of this study are to be better implemented to the activities at the military academy.

Social implications

The closest civilian occupational equivalent is a computer network operations (CNO)-operator. The findings could be implemented into their daily work routines.

Originality/value

Cognitive tests used in this study are based on recognized general cognitive tests. However, modifications were made to suit the cyber task context, making the test original. The cyber officer is a contemporary concept currently lacking research.

Sleep Quality in Family Caregivers of Individuals With Dementia

Poor sleep quality in family caregivers may impact their health status and cause quality of life to decline. Nurses are conducting an increasing number of studies that use sleep quality or related concepts as a main indicator to assess caregiver’s sleep. Therefore, a clear understanding of sleep quality and how it is different from other relevant sleep domains is essential. This article aimed to analyze the concept of sleep quality using the steps outlined by Walker and Avant. Findings include (a) attributes of sleep quality including subjective perception of sleep, sleep hours, and evaluation of activity after awaking; (b) antecedents of sleep quality including the ability to get naturally into the sleep cycle and status of conscious state; and (c) consequences of sleep quality including bio-psycho-social and global dimensions of health. This article intends to help clinicians and researchers better understand and define sleep quality in dementia caregivers.

Sleep deprivation and adverse health effects in United States Coast Guard responders to Hurricanes Katrina and Rita

OBJECTIVE

Disaster responders are increasingly called upon to assist in various natural and manmade disasters. A critical safety concern for this population is sleep deprivation; however, there are limited published data regarding sleep deprivation and disaster responder safety.

DESIGN

We expanded upon a cross-sectional study of 2695 United States Coast Guard personnel who responded to Hurricanes Katrina and Rita. Data were collected via survey on self-reported timing and location of deployment, missions performed, health effects, medical treatment sought, average nightly sleep, and other lifestyle variables. We created a 4-level sleep deprivation metric based on both average nightly reported sleep (d5hours; >5hours) and length of deployment (d2weeks; >2weeks) to examine the association between sustained sleep deprivation and illnesses, injuries, and symptoms using logistic regression to calculate odds ratios (ORs) and 95% confidence intervals.

RESULTS

The strongest, statistically significant positive ORs for the highest sleep deprivation category compared with the least sleep-deprived category were for mental health and neurologic effects, specifically depression (OR=6.76), difficulty concentrating (OR=8.33), and confusion (OR=11.34), and for dehydration (OR=9.0). Injuries most strongly associated with sleep deprivation were twists, sprains, and strains (OR=6.20). Most health outcomes evaluated had monotonically increasing ORs with increasing sleep deprivation, and P tests for trend were statistically significant.

CONCLUSION

Agencies deploying disaster responders should understand the risks incurred to their personnel by sustained sleep deprivation. Improved planning of response efforts to disasters can reduce the potential for sleep deprivation and lead to decreased morbidity in disaster responders.

Current and future directions in clinical fatigue management: An update for emergency medicine practitioners

Physicians worldwide are working round the clock to meet the demands of healthcare systems, especially in acute medical settings such as EDs. Demanding shift work schedules cause fatigue and thus deterioration in mood and motor performance. This article explores the effects of sleep deprivation, focusing on cognition, executive decision-making and the implications for clinical care. Humans are capable of functioning and even adapting to sleep restriction; however, clinicians should be aware of pitfalls and absolute minimums for sleep. Fatigue management training shows promise in enhancing safety in aviation and might have a role in medical shift work. Strategic napping improves performance during night shift in the ED, but does not fully negate fatigue. Drugs offer limited benefit for performance under sleep-deprived conditions, and whenever possible, sleep and/or strategic napping takes precedence.