Psychomotor vigilance performance predicted by Epworth Sleepiness Scale scores in an operational setting with the United States Navy

The article of record as published may be located at http://dx.doi.org/10.1111/jsr.12243It is critical in operational environments to identify individuals who are at higher risk of psychomotor performance impairments. This study assesses the utility of the Epworth Sleepiness Scale for predicting degraded psychomotor vigilance performance in an operational environment. Active duty crewmembers of a USA Navy destroyer (N = 69, age 21–54 years) completed the Epworth Sleepiness Scale at the beginning of the data collection period. Participants wore actigraphs and completed sleep diaries for 11 days. Psychomotor vigilance tests were administered throughout the data collection period using a 3-min version of the psychomotor vigilance test on the actigraphs. Crewmembers with elevated scores on the Epworth Sleepiness Scale (i.e. Epworth Sleepiness Scale >10) had 60% slower reaction times on average, and experienced at least 60% more lapses and false starts compared with individuals with normal Epworth Sleepiness Scale scores (i.e. Epworth Sleepiness Scale ≤10). Epworth Sleepiness Scale scores were correlated with daily time in bed (P < 0.01), sleep (P < 0.05), mean reaction time (P < 0.001), response speed 1/reaction time (P < 0.05), slowest 10% of response speed (P < 0.001), lapses (P < 0.01), and the sum of lapses and false starts (P < 0.001). In this chronically sleep-deprived population, elevated Epworth Sleepiness Scale scores identified that subset of the population who experienced degraded psychomotor vigilance performance. We theorize that Epworth Sleepiness Scale scores are an indication of personal sleep debt that varies depending on one’s individual sleep requirement. In the absence of direct performance metrics, we also advocate that the Epworth Sleepiness Scale can be used to determine the prevalence of excessive sleepiness (and thereby assess the risk of performance decrements)

Assessment of a novel 3hrs-on/3hrs-off/3hrs- on/15hrs-off watchstanding schedule on the USS STOCKDALE (DDG-106)

This study assessed the utility of the novel 3hrs-on/3hrs-off/3hrs-on/15hrs-off (3-3-3-15) watchstanding schedule on the USS STOCKDALE (DDG 106) while the ship was conducting underway operations. Crewmembers (N=129) completed a survey to provide their opinion about the utility and the acceptance of the 3-3-3-15 as compared to their previous schedule, i.e., the 3hrs-on/9hrs-off (3/9). The novelty of the 3-3-3-15 lies in the clustering of the two shifts, which are divided by a 3-hour off period, and the long 15-hour off period after the second shift. The predicted effectiveness of the 3-3-3-15 was assessed with the Fatigue Avoidance Scheduling Tool (FAST). Crewmembers reported sleeping 5.80±1.23 hours daily. The average PSQI Global score was 7.29±2.89, with ~73% of the participants identified as “poor sleepers”. In comparison to the 3/9, the average rate of non-negative responses of the 3-3-3-15 (to include positive and neutral responses) ranged between 80% and 90%. The largest acceptance (positive) rates were identified in sleep affordability, the adequacy of time to complete off-watch duties and shipboard/departmental qualifications, to work out, to have more personal time, to be able to plan daily activities. Given that sleep satisfaction and acceptance rates of the 3-3-3-15 were equivalent or better than other watchstanding schedules, our results suggest that the 3-3-3-15 may be a useful schedule from an ergonomic and sleep hygiene perspective. Evidence also suggest, however, that the 3-3-3-15 may not be as good for officers whose duties demand high level of situational awareness about ship operations, for watchstanders in the Operations Department or for bridge watch duties. Overall, the 3-3-3-15 has the potential to be a useful alternative to existing watch standing schedules in terms of crew fatigue levels, acceptance by the crewmembers, and workload management when working in a Navy vessel. Being a novel schedule, however, more effort should be focused on how to best implement the 3-3-3-15 on a ship, and what are the factors that affect the utility of the 3-3-3-15 at sea.Prepared for: Dr. Brian Bingham, CRUSER DirectorApproved for public release; distribution is unlimited

Assessment of the fixed 3-section 4hrs-on/8hrs-off watchstanding schedule in sailors of the Swedish Royal Navy compared to sailors of the United States Navy

This prospective longitudinal quasi-experimental study assessed the utility of the 3-section, fixed, 4hrs-on/8hrs-off watchstanding schedule on a ship of the Swedish Royal Navy (HSwMS ORIOΝ). Sailor (n = 19) state was assessed in terms of sleep attributes, fatigue, insomnia symptoms, mood, psychomotor vigilance performance, and workload. Data from the HSwMS ORIOΝ were compared with data from sailors from three surface vessels of the USN (n = 22). Compared to their USN peers, sailors on the HSwMS ORION were more alert, reported better sleep quality, less severe insomnia symptoms, and better mood in terms of total mood disturbance, depression, fatigue, and vigor. The same pattern was evident in psychomotor vigilance performance, i.e., sailors on the HSwMS ORION were faster and made fewer errors as assessed by lapses or lapses combined with false starts. Sailors in the two samples did not differ in terms of daily sleep duration and the number of sleep episodes per day. Also, daily work duration did not differ substantively between the two groups. We postulate that one factor that explains why Swedish sailors felt and performed better is the fact that sailors in night shifts were allowed to wake up later in the day, and, consequently some work duties occurred later in the day. In conclusion, our findings suggest the sailor well-being when standing watch on the fixed 4/8 can be improved when sailors are allowed flexible wake-up times in the morning after a night shift. Given the small number of participants, however, further research is needed to understand better the advantages and disadvantages of the 4/8 in the naval operational environment, and how to improve the utility of the watchbill.Approved for public release; distribution is unlimited

Wrist-Worn Psychomotor Vigilance Task Device Validation Study

Prepared for: Naval Advanced Medical Development Program; Naval Medical Research Center; 503 Robert Grant Avenue, Silver Spring, MD 20910Collecting reliable human performance data in military operational environments is an ongoing challenge. A major issue of concern is identifying systems that can capture human performance metrics in a reliable and valid manner in the field. One task that has been used extensively in the laboratory - and more recently in field settings - is the Psychomotor Vigilance Test (PVT). Since 2008 the PVT has been included as a feature on a wrist-worn actigraph (AMI, Inc.), thereby enabling researchers to easily administer the PVT in the field. The current project has three aims, a) to validate the 3-minute PVT which is currently embedded in the AMI actigraph, b) to explore the utility of other devices for field use, and c) to provide recommendations for the collection of PVT data in the military operational environments. In our studies, we found that when the screen backlight is illuminated, the results of the 3-minute PVT on the AMI actigraph are comparable to those from the laptop PVT. These findings demonstrate that the 3-minute PVT on the AMI actigraph is a valid alternative to the 3-minute laptop-based PVT for field assessment. Given the widespread use of hand-held devices with a touch screen interface, we also tested a PVT application on a representative touch screen device. Our findings were disappointing, showing that the hand-held touch screen PVT system was not comparable to the validated PVT. In particular, the touch screen PVT introduced a large constant bias as well as a proportional bias that decreased the range of response speed. These findings raised the question of what the appropriate user interface should be for a field-grade PVT system. Herein, we present a method we have developed and refined over multiple years to prepare PVT data collected in field setting for analysis. This method reduces bias due to missing data and artifacts from external disturbances by assessing the quality of the PVT data on three levels: the raw response level, the aggregated (trial) level, and the participant level. In brief, our experience of collecting PVT data, combined with findings from this current 3 year effort, suggests that when administering the PVT in field settings, it is best if the PVT is embedded in a wearable device such as the AMI device. While other types of devices (e.g., smartphones, iPods, tablets, etc.) can be used for PVT administration, they have important constraints which should be taken into consideration.Naval Medical Research Center Advanced Medical Development ProgramNaval Advanced Medical Development Program; Naval Medical Research CenterApproved for public release; distribution is unlimited

A Dynamic Process Model for the Design and Assessment of Network Systems

Proceedings of the 2006 Command and Control Research and Technology Symposium, San Diego, CA June 2006.This paper won the Gary F. Wheatley Best Paper Award for the entire conference.Modern warfare has witnessed the proliferation of coalition efforts to contain terrorism. To be successful, these efforts rely upon the effective integration of human and technological agents. Typically, models and analyses of network centric warfare (NCW) focus on technological aspects of a system, eschewing the roles, contributions and decisions made by humans. The Dynamic Model of Situated Cognition (DMSC) emerged as an attempt to represent relationships between technology and humans in a system. The model has been applied in a variety of contexts: individual performance, military command and control, naval operations, human error in military mishaps, and, most recently, to modeling team behavior in complex organizations (Miller & Shattuck, 2004, 2005a, b; Shattuck & Miller, 2004, 2005; Miller, Shobe & Shattuck, 2005). During the 2004 CCRT Symposium, we introduced “A Process Model of Situated Cognition in Military Command and Control.” We have expanded and refined the model over the last two years and it continues to be well received. In this paper, we review these changes and extend the Dynamic Model of Situated Cognition to serve as an aid for system designers as they consider how individual and team behaviors emerge and interact with complex technology in a system context

0776 Differences in Well-Being in Dayworkers Compared to Shift Workers: A Study of United States Navy Sailors

17 USC 105 interim-entered record; under review.The article of record as published may be found at https://doi.org/10.1093/sleep/zsaa056.772Introduction: On United States Navy (USN) ships, most sailors are shift workers, required to support 24/7 operations. However, ~15% of the ship’s company are solely dayworkers who do not work in shifts. It is often assumed that the quality of life for dayworkers is better than that of shift workers. This study compared the well-being of dayworkers with that of shift workers. Methods:Longitudinal, naturalistic observations were made of sailors (N=926; 18-59 years of age, ~80% males, ~84% enlisted personnel) on seven US Navy ships while performing their normal underway duties. Sleep-related attributes (actigraphy, Epworth Sleepiness Scale, Pittsburgh Sleep Quality Index, Insomnia Severity Index), mood (Profile of Mood States), and work/rest patterns were assessed. Results: Dayworkers (DW; n=98) were on average older (p=0.001) and more senior (p=0.001) than shift workers (SW). Of the dayworkers, 31% reported elevated daytime sleepiness (SW:45.5%; p=0.008), 64.2% were poor sleepers (SW:82.6%; p10 and ISI≥15 (SW:16.8%; p=0.626).Dayworkers had better mood (Total Mood Disturbance, anger/hostility, vigor, fatigue; all p0.300) in their use of caffeinated beverages (82%-86%), use of nicotine products (30%-36%), or having a regular exercise routine (69%-75%). In both groups, ~9% of sailors drank caffeinated beverages, used nicotine products and did not have an exercise routine (p=0.999). Dayworkers worked 10.1 hours/day, i.e., 1.7 hours/day less than watchstanders (p<0.001). Conclusion: Quality of life of dayworkers is a bit better when compared to shift workers, but sleep-related issues are evident in almost all US Navy sailors. Living and working on a naval vessel takes a toll on almost everyone aboard. A culture change is required!Supported by the Naval Medical Research Center’s Advanced Medical Development Program, the US Navy 21st Century Sailor Office, and the US Navy OPNAV N1

0821 Gender Differences in Sailor Well-Being, Sleep-Related Behaviors, and Psychomotor Vigilance Performance in the United States Navy

17 USC 105 interim-entered record; under review.The article of record as published may be found at https://doi.org/10.1093/sleep/zsaa056.817Introduction: Approximately 18% of US Navy sailors are females. Research has shown gender-related differences in the prevalence of sleep disorders in active duty personnel (Foster et al., 2017). Specifically, insomnia, depression, and anxiety are more prevalent in females, while obstructive sleep apnea is more prevalent in males. We have studied the sleep patterns and fatigue levels of crew members on more than 30 US Navy ships. The current study focuses on gender differences in well-being, sleep-related behaviors, and psychomotor vigilance performance of sailors in the US Navy. Methods: Using a longitudinal, naturalistic observation paradigm, data were collected from crewmembers on nine USN ships while performing their normal underway duties. Participants (N=1,056) tended to be young (on average 27 years of age), predominantly male (80.6%), and enlisted (84.8%). We assessed average daytime alertness (Epworth Sleepiness Scale), insomnia symptoms (Insomnia Severity Index), mood (Profile of Mood States), and sleep quality (Pittsburgh Sleep Quality Index). Sleep was assessed with actigraphy and logbooks. Sailors performed a 3-minute version of the Psychomotor Vigilance Task (PVT), which was built into their wrist-worn actigraph. Results: Compared to males, female sailors reported more depressive symptoms (p=0.042) and less vigor (p<0.001). Females slept more (daily sleep duration: p<0.001) but their sleep was split into more episodes than their male counterparts (p=0.029). Fewer females reported a regular exercise routine (p=0.033). In addition, females report consuming fewer energy drinks (p=0.007), and using fewer nicotine products (p=0.013). Lastly, consistent with findings from civilian populations, female sailors had slower reaction times on the PVT (p<0.001) and experienced more lapses combined with false starts (p<0.001) than their male counterparts. Conclusion: Compared to their male peers, female sailors tend to report higher levels of depression and lower levels of vigor. They experience more pronounced split sleep, are less likely to report having an exercise routine, and have poorer performance on the PVT. Fewer females report using energy drinks and nicotine products.This research was supported by the Naval Medical Research Center’s Advanced Medical Development Program, the US Navy 21st Century Sailor Office, and the US Navy OPNAV N1

0172 Prevalence of Insomnia and Excessive Daytime Sleepiness in US Navy Sailors

Sleep, Volume 40, Issue suppl_1, 28 April 2017, Page A64The article of record as published may be found at https://doi.org/10.1093/sleepj/zsx050.171The most common sleep-related complaint in civilian populations is insomnia. Workers in the U.S. Navy regularly experience significant levels of sleep deprivation and circadian misalignment due to long workdays and chronic shiftwork. This study assessed the prevalence of insomnia and elevated daytime sleepiness of crewmembers underway on a United States Navy ship while working

0173 The Effect of Sleep on Mood of U.S. Navy Sailors

Sleep, Volume 41, Issue suppl_1, April 2018, Page A68,The article of record as published may be found at https://doi.org/10.1093/sleepj/zsx050.171U.S. Navy crewmembers experience sleep deprivation and circadian misalignment due to long workdays. They frequently work rotating schedules that impose >6 hr of jetlag daily, resulting in disrupted circadian rhythms. This study assessed sleep and mood of crewmembers on a Navy ship