Sleepy and grumpy go hand in hand for US Navy Sailors.

Study Objectives: The study explores how sleep, sleep-related practices, and behaviors, in addition to various demographic and occupational characteristics, are related to overall mood of US Navy sailors when they are underway. Methods: Longitudinal assessment of US Navy sailors performing their underway duties (N = 873, 79.2% males, median age 25 years). Participants completed standardized questionnaires, wore wrist-worn actigraphs, and completed daily activity logs. Results: Sailors who reported worse profile of mood states (POMS) total mood disturbance scores had shorter sleep duration, worse sleep quality, and more episodes of split sleep. The group with worse mood also reported more symptoms of excessive daytime sleepiness as well as more symptoms of insomnia. In addition to sleep results, sailors with worse mood also tended to be younger, more likely to use nicotine and tobacco products, and less likely to have an exercise routine when compared to sailors with better POMS scores. Finally, the group with worse POMS scores included more enlisted personnel, tended to work more hours per day, and were more likely to stand watch-especially on rotating watch schedules. Conclusions: The results found significant associations between the sleep practices and mood of sailors aboard US Navy ships. Numerous other demographic and occupational factors were also strongly associated with mood. This paper is part of the Sleep and Circadian Rhythms: Management of Fatigue in Occupational Settings Collection.

Sex differences in US military personnel with insomnia, obstructive sleep apnea, or comorbid insomnia and obstructive sleep apnea.

STUDY OBJECTIVES: The aim of this study was to evaluate sex-related differences in symptoms of sleep disorders, sleep-related impairment, psychiatric symptoms, traumatic brain injury, and polysomnographic variables in treatment-seeking military personnel diagnosed with insomnia, obstructive sleep apnea (OSA), or comorbid insomnia and OSA (COMISA). METHODS: Participants were 372 military personnel (46.2% women, 53.8% men) with an average age of 37.7 (standard deviation = 7.46) years and median body mass index of 28.4 (5.50) kg/m2. Based on clinical evaluation and video-polysomnography, participants were diagnosed with insomnia (n = 118), OSA (n = 118), or COMISA (n = 136). Insomnia severity, excessive daytime sleepiness, sleep quality, nightmare disorder, sleep impairment, fatigue, posttraumatic stress disorder, anxiety, depression symptoms, and traumatic brain injury were evaluated with validated self-report questionnaires. Descriptive statistics, parametric and nonparametric t-tests, and effect sizes were used to assess sex differences between men and women. RESULTS: There were no significant differences between women and men with insomnia or OSA in sleep-related symptoms, impairment, or polysomnography-based apnea-hypopnea index. Military men with COMISA had a significantly greater apnea-hypopnea index as compared to military women with COMISA, but women had greater symptoms of nightmare disorder, posttraumatic stress disorder, and anxiety. CONCLUSIONS: In contrast to civilian studies, minimal differences were observed in self-reported sleep symptoms, impairment, and polysomnography metrics between men and women diagnosed with the most frequent sleep disorders in military personnel (ie, insomnia, OSA, or COMISA) except in those with COMISA. Military service may result in distinct sleep disorder phenotypes that differ negligibly by sex. CITATION: Mysliwiec V, Pruiksma KE, Matsangas P, et al. Sex differences in US military personnel with insomnia, obstructive sleep apnea, or comorbid insomnia and obstructive sleep apnea. J Clin Sleep Med. 2024;20(1):17-30.

Cervical headgear therapy and sleep-related attributes.

INTRODUCTION: The study aimed to assess (1) the effect of the treatment with cervical headgear on patients' sleep-related attributes and well-being and (2) whether these sleep-related parameters (ie, sleep quality and quantity) were associated with patients' compliance during the orthodontic treatment. METHODS: The study protocol was based on a prospective longitudinal quasi-experimental design. Participants (n = 26; 9 males; mean age, 12.4 ± 1.68 years) were patients in the Postgraduate Orthodontic Clinic, National and Kapodistrian University of Athens. All patients received treatment with a cervical headgear having an embedded TheraMon microsensor. Sleep was assessed by wrist-worn actigraphy for 59 ± 19 days. The Epworth Sleepiness Scale was used to assess average daytime sleepiness, whereas we used the Athens Insomnia Scale for insomnia symptoms. Oral health-related quality of life (OHRQOL) was assessed by the Oral Health Impact Profile (OHIP-14). RESULTS: Patients slept on average 7.35 ± 0.42 h/d. Compared with the lowest sleep duration recommended for their age group, patients had an average chronic sleep deficit of 1.40 ± 0.49 h/d. Patients wore the headgear 90.9% of the days for 10.40 ± 4.17 h/d. However, only 7 (28%) patients reached or exceeded the wear-time recommendation of 12 h/d. In contrast, 2 (8%) patients wore headgear <5 h/d, 11 (44%) 5-10 h/d, and 12 (48%) patients wore headgear >10 h/d. Aggregated by participants, the median Epworth Sleepiness Scale score during the study was 3.40 (interquartile range [IQR], 4.85; range, 0.2-13.6), the median Athens Insomnia Scale score was 3.00 (IQR, 4.25; range, 0-7), and the median Oral Health Impact Profile score was 1.40 (IQR, 4.17; range, 0.0-20.8). Compared with patients who wore the orthodontic appliance >7.8 h/d, patients who wore it <7.8 h/d had worse average daytime sleepiness (P = 0.050) and worse OHRQOL (P = 0.019). CONCLUSIONS: Orthodontic treatment with cervical headgear has no substantive negative effect on sleep attributes (quantity and quality), average daytime sleepiness and OHRQOL. However, poor compliance with orthodontic treatment seems to be associated with higher levels of daytime sleepiness.

Using Light to Facilitate Circadian Entrainment from Day to Night Flights.

BACKGROUND: As part of a larger project to provide recommendations regarding limitations and best practices for shifting aviators from day to night operations, a study was conducted to assess the efficacy of high energy visible (HEV) light to shift the circadian rhythm in humans. The study attempted to replicate the patterns of military aviators who could be required to shift abruptly from day to night flight operations.METHODS: Simulated flight performance and salivary melatonin levels of 10 U.S. military aviators were collected over a 3-night period using a within-subject dim light melatonin onset (DLMO) study design. Data were collected in a laboratory with participants returning home to sleep following each of the three evenings/nights of data collection. Light treatment included a single 4-h exposure of blue-enriched white light (∼1000 lux) on night 2. Data collected included melatonin levels, light exposure, sleepiness, cognitive workload, and simulated flight performance.RESULTS: The average delay in melatonin onset was 1.32 ± 0.37 h (range: 53 min to 1 h 56 min). Sleepiness (P = 0.044) and cognitive workload (P = 0.081) improved the night following the light treatment compared to the baseline. No systematic differences were identified in flight performance.DISCUSSION: The HEV light treatment successfully delayed the circadian phase of all participants even though participants' ambient light levels (including daylight) outside the laboratory were not controlled. These findings were used to develop circadian synchronization plans for aviators who are asked to transition from day to night operations. These plans will be assessed in a follow-on study in an operational unit.Shattuck NL, Matsangas P, Reily J, McDonough M, Giles KB. Using light to facilitate circadian entrainment from day to night flights. Aerosp Med Hum Perform. 2023; 94(2):66-73.

Clinical and polysomnographic features of trauma associated sleep disorder.

STUDY OBJECTIVES: Trauma associated sleep disorder is a proposed parasomnia that develops after trauma with clinical features of trauma related nightmares, disruptive nocturnal behaviors, and autonomic disturbances. The purpose of this case series is to better characterize the clinical and video-polysomnographic features of patients meeting clinical criteria for this proposed parasomnia. METHODS: Semistructured clinical interview and detailed video-polysomnography review of 40 patients. Movements and vocalizations in rapid eye movement sleep were quantified according to the rapid eye movement sleep behavior disorder severity scale. RESULTS: Patients (n = 40, 32 males) were service members and veterans with a median age of 38.9 years (range 24-57 years) who reported trauma related nightmares and disruptive nocturnal behaviors at home. On video-polysomnography, 28 (71.8%) patients had disruptive nocturnal behaviors in rapid eye movement sleep consisting of limb, head, and axial movements; vocalizations were present in 8 (20%). On the rapid eye movement sleep behavior disorder severity scale, most (n = 28, 71.8%) had a low rating but those with greater severity (n = 11, 28.2%) had a higher prevalence of posttraumatic stress disorder (P = .013) and markedly less N3 sleep (P = .002). The cohort had a high rate of insomnia (n = 35, 87.5%) and obstructive sleep apnea (n = 19, 47.5%). Most patients were treated with prazosin (n = 29, 72.5%) with concomitant behavioral health interventions (n = 25, 64.1%); 15 (51.7%) patients receiving prazosin reported improved symptomatology. CONCLUSIONS: Disruptive nocturnal behaviors can be captured on video-polysomnography during rapid eye movement sleep, although they may be less pronounced than what patients report in their habitual sleeping environment. Clinical and video-polysomnographic correlations are invaluable in assessing patients with trauma associated sleep disorder to document objective abnormalities. This case series provides a further basis for establishing trauma associated sleep disorder as a unique parasomnia. CITATION: Brock MS, Matsangas P, Creamer JL, et al. Clinical and polysomnographic features of trauma associated sleep disorder. J Clin Sleep Med. 2022;18(12):2775-2784.

Who sleeps more and who works longer in the US Navy: Officers or enlisted personnel?

OBJECTIVES: To determine whether United States Navy (USN) officers and enlisted personnel have different sleep and work patterns while underway on USN surface ships. METHODS: Variables of interest were assessed by actigraphy, activity logs, and validated questionnaires. RESULTS: The 2 groups had similar daily sleep (officers: 6.41 ± 0.95 hrs/day; enlisted: 6.57 ± 0.97 hrs/day) and work duration. Enlisted personnel, however, were more likely to report excessive daytime sleepiness-EDS (41% more likely), clinically relevant insomnia (105%), to have both EDS and elevated insomnia (121%), to be classified as poor sleepers (17%), to use nicotine products (174%), and to forego routine exercise (57%). Enlisted personnel were 487% more likely to report all 3 of these behaviors: drink caffeinated beverages, use nicotine/tobacco products, forego routine exercise. CONCLUSIONS: Even though the work and sleep hours do not differ significantly, the state of well-being of enlisted personnel is in general lower than officers. Our findings can provide insight to Navy leadership towards improving sailor well-being and crew endurance.

Performance comparison of peripheral arterial tonometry-based testing and polysomnography to diagnose obstructive sleep apnea in military personnel.

STUDY OBJECTIVES: Obstructive sleep apnea (OSA) is increasingly common among military personnel, but diagnostic capabilities are challenged by limited capability for polysomnography (PSG). We sought to evaluate the diagnostic properties of peripheral arterial tonometry (PAT)-based home sleep apnea testing (HSAT) to accurately identify and classify OSA among active-duty military personnel. METHODS: This study was a retrospective review of all patients suspected of having OSA who completed an initial PAT-based HSAT followed by confirmatory PSG within 120 days. The diagnostic properties of a PAT-based, HSAT-derived apnea-hypopnea index (AHI) vs a PSG-derived AHI were assessed. RESULTS: Two hundred eight matched pairs of asynchronous studies were analyzed. The prevalence of OSA was 63.5%. PAT-based HSAT overdiagnosed 27.4% of patients with OSA and underdiagnosed 46.6% of patients with OSA. The majority (n = 116, 55.8%) of patients changed OSA severity classification (absent, mild, moderate, severe) after PSG. OSA severity classification concordance between PAT-based HSAT and PSG was observed in 53.4%, 40.5%, 28.6%, and 40.0% of patients with absent, mild, moderate, and severe OSA, respectively. Receiver operating characteristic curve analysis showed an area under the curve of 0.715 and a proposed PAT-based, HSAT-derived AHI cutoff score for OSA diagnosis of 9.0 events/h. This PAT-based, HSAT-derived AHI provided a 52% sensitivity, 83% specificity, 84% positive predictive value, and 50% negative predictive value. Bland-Altman plots showed an unacceptable degree of agreement between PAT-based, HSAT-derived AHI and AHI. CONCLUSIONS: There is significant discordance between PAT-based HSAT and PSG among active-duty military personnel evaluated for OSA. PAT-based HSAT may have limited utility for diagnosing OSA and grading severity in this unique patient population. CITATION: O'Reilly BM, Wang Q, Collen J, Matsangas P, Colombo CJ, Mysliwiec V. Performance comparison of peripheral arterial tonometry-based testing and polysomnography to diagnose obstructive sleep apnea in military personnel. J Clin Sleep Med. 2022;18(6):1523-1530.

Small Boat Recovery Task Performance in a Moving Environment.

OBJECTIVE: Assess operator performance in a simulation of US Coast Guard small boat recovery to a larger vessel on a large scale, six degree-of-freedom, full motion simulator. BACKGROUND: Studies of human performance in small boat recovery task have never been conducted on a high amplitude, low frequency simulator. Empirical evidence of small boat recovery task performance in challenging motion conditions is needed to inform future maritime systems designs. METHOD: Experienced active-duty boat crewmembers (N = 13) conducted a small boat recovery task in three sea states on the Vertical Motion Simulator (VMS) at the NASA Ames Research Center. Task performance was assessed using a task equivalent for time to complete the task. Participant behaviors associated with increasing motion severity were observed. RESULTS: Task performance declined as motion conditions became more severe. Participants were more likely to use at least one hand to maintain balance during motion conditions, becoming more frequent with increasing motion severity. Many participants used one hand to complete the task despite contrary instructions and previous experience. CONCLUSION: Two design recommendations were proposed to counter declining task performance in increasingly severe motion conditions. Handholds available to participants during the task, and task design supporting single handed completion were recommended for small boat recovery systems. APPLICATION: This research is directly applicable to gross motor tasks requiring simultaneous maintenance of balance in a maritime environment, and may be extended to other environments where humans experience complex motions while completing tasks.

Habitability in Berthing Compartments and Well-Being of Sailors Working on U.S. Navy Surface Ships.

OBJECTIVE: The study had two objectives: (a) to assess the prevalence of sleep-related habitability concerns in the berthing compartments of U.S. Navy surface ships and (b) to assess whether habitability issues in berthing compartments affected the sleep and well-being of crew members. BACKGROUND: The importance of habitability for human well-being is recognized. Little is known, however, about the association between habitability factors in the sleeping/berthing compartments and sailor well-being in operational conditions. METHOD: Fit-for-duty sailors (N = 1,269; from six ships) participated in this naturalistic and longitudinal study. Sailors reported habitability factors affecting their sleep and completed four standardized questionnaires to assess daytime sleepiness, insomnia, sleep quality, and mood. Sleep was assessed through wrist-worn actigraphy and activity logs. RESULTS: Noise, ambient temperature, poor bedding conditions, and ambient light were the most frequently reported factors of concern. Compared to their peers with fewer complaints, sailors with more habitability-related complaints were more likely to have elevated daytime sleepiness (by 23%) and to report insomnia symptoms (145%) and lower sleep quality (21%). Sailors who reported more habitability-related issues also tended to sleep longer. Individuals with more complaints about habitability also tended to report worse mood (total mood disturbance, tension/anxiety, depression, fatigue, and confusion/bewilderment). CONCLUSION: Habitability-related complaints are associated with sailor well-being and sleep. Future studies should expound on the various detrimental factors that degrade conditions in berthing compartments and negatively impact crew well-being. APPLICATION: Habitability in berthing compartments of surface ships is associated with sailors' daytime sleepiness, insomnia severity, mood, and sleep attributes. Ship designers should take these findings into consideration and investigate viable and cost-effective methods to mitigate the problems we identified.

Eating behaviors in sailors of the United States Navy: Meal-to-sleep intervals.

BACKGROUND: Due to their long workdays and erratic watch schedules, sailors on United States Navy (USN) ships often eat meals close to their bedtime, which may contribute to sleep disruption. AIM: To assess the duration of meal-to-sleep (M-S) intervals in relation to timing of sailor workdays and watch schedules. METHODS: Longitudinal field assessment of USN sailors performing their underway duties (N = 234). Participants completed questionnaires, wore actigraphs, and completed activity logs. RESULTS: Approximately 35% of M-S intervals were <3 h in duration. M-S interval duration was associated with watchstanding status (p < 0.001) and the number of sections in the watchstanding schedule (p < 0.001). Sailors on the two-section watch schedule had, on average, the shortest M-S intervals (55 min) compared to sailors on three- or four-section watchbills (∼4 h) and to non-watchstanders (4.85 h). CONCLUSION: Sailors on two-section watchbills often eat quite close to bedtime. To provide appropriate recommendations regarding healthy dietary patterns, we will continue assessing dietary behaviors and food choices of sailors while underway, especially as they relate to sailor work hours, circadian rhythms, and sleep practices.

Does the quality of life differ for shift workers compared to day workers?

It is often assumed the quality of life of dayworkers is better than that of shiftworkers. Our findings from United States Navy (USN) sailors (N = 804, 78.4% males) showed dayworkers slept better, were less sleepy, and reported greater vigor and reduced fatigue (Profile of Mood States) than shiftworkers. Nevertheless, ~25% of dayworkers slept <6.5 h/d, ~62% had split sleep, 31% reported excessive daytime sleepiness (EDS), and ~64% were poor sleepers (Pittsburgh Sleep Quality Index). The two groups had similar sleep-related behaviors, rates of insomnia, comorbid EDS/insomnia, and scores on total mood disturbance, tension/anxiety, depression, anger/hostility, and confusion/bewilderment. The findings of our study indicate shipboard sleep-related issues are prevalent among USN sailors.

Sleep quality, occupational factors, and psychomotor vigilance performance in the U.S. Navy sailors.

STUDY OBJECTIVES: This field study (a) assessed sleep quality of sailors on the U.S. Navy (USN) ships while underway, (b) investigated whether the Pittsburgh Sleep Quality Index (PSQI) scores were affected by occupational factors and sleep attributes, and (c) assessed whether the PSQI could predict impaired psychomotor vigilance performance. METHODS: Longitudinal field assessment of fit-for-duty USN sailors performing their underway duties (N = 944, 79.0% males, median age 26 years). Participants completed questionnaires, wore actigraphs, completed logs, and performed the wrist-worn 3-min Psychomotor Vigilance Task (PVT). RESULTS: Sailors slept on average 6.60 ± 1.01 h/day with 86.9% splitting their sleep into more than one episode/day. The median PSQI Global score was 8 (interquartile range [IQR] = 5); 80.4% of the population were classified as "poor sleepers" with PSQI scores >5. PSQI scores were affected by sailor occupational group, rank, daily sleep duration, and number of sleep episodes/day. Sleep quality showed a U-shape association with daily sleep duration due to the confounding effect of split sleep. Sailors with PSQI scores >9 had 21.1% slower reaction times (p < 0.001) and 32.8%-61.5% more lapses combined with false starts (all p < 0.001) than sailors with PSQI scores ≤9. Compared to males and officers, females and enlisted personnel had 86% and 23% higher risk, respectively, of having PSQI scores >9. Sailors in the PSQI > 9 group had more pronounced split sleep. CONCLUSIONS: Working on Navy ships is associated with elevated PSQI scores, a high incidence of poor sleep, and degraded psychomotor vigilance performance. The widely used PSQI score>5 criterion should be further validated in active-duty service member populations.

Hand-Held and Wrist-Worn Field-Based PVT Devices vs. the Standardized Laptop PVT.

BACKGROUND: Given the challenges of collecting reliable Psychomotor Vigilance Task (PVT) data in the field, this study compared a 3-min PVT on a hand-held device and wrist-worn device vs. a standardized laptop.METHODS: The experiment utilized a randomized, repeated-measures design. Subjects (N = 36) performed the PVT on a touch-screen, hand-held device (HHD), a wrist-worn device (WWD), and a standardized laptop (L). Sleep was assessed using wrist-worn actigraphy.RESULTS: Compared to the L, the HHD was slower on average (∼50% longer reaction times; ∼34% slower response speeds; ∼600% more lapses in attention combined with false starts) and introduced a proportional bias that decreased the range of response speeds by 60%. Compared to the L, the WWD with the backlight on was faster on average (reaction time: ∼6%; response speed: ∼13%), but equivalent in lapses combined with false starts, and introduced a proportional bias that increased the range of responses by 60%.DISCUSSION: Compared to the L PVT, using a hand-held, touch screen interface to collect PVT data may introduce a large constant bias and a proportional bias that decreases the range of response speed. However, performance on the WWD closely mirrors performance on the L PVT and the proportional bias tends to be in favor of detecting individuals with slower responses. Researchers should avoid comparing PVT metrics between different device types. Reliability of PVT data from a WWD or HHD may be degraded when used in an operational setting with unpredictable environmental movement (such as a surface maritime setting).Matsangas P, Shattuck NL. Hand-held and wrist-worn field-based PVT devices vs. the standardized laptop PVT. Aerosp Med Hum Perform. 2020; 91(5):409-415.

Sleep-Related Practices, Behaviors, and Sleep-Related Difficulties in Deployed Active-Duty Service Members Performing Security Duties.

Objective: To assess sleep-related difficulties (e.g., trouble staying asleep, oversleeping, falling asleep while on duty, disturbing dreams, sleep paralysis) and behavioral patterns of active-duty service members (ADSMs) performing security duties. Participants: The participants were 1,169 ADSMs (20-44 years of age). Methods: ADSMs completed an online survey (67.3% response rate) with items assessing demographics, the occupational environment, sleep-related attributes, habits, or difficulties, factors affecting sleep, aids and techniques used to improve sleep, and the use of sleep-related products. Results: ADSMs reported sleeping ~6.5 hr/day (~56% reported sleeping < 6 hr). Sleep-related difficulties were reported by ~72% of the ADSMs (i.e., 55.1% had problems staying asleep, 33.1% reported experiencing sleep paralysis, 25.6% reported oversleeping, 21.6% had disturbing dreams, and 4.79% reported falling asleep while on duty). Daily sleep duration and quality, occupational factors (shift work, operational commitments, collateral duties, habitability, taking antimalarial medication, years deployed), and personal factors or behaviors (history of sleep problems, problems in personal life, late exercise times, altering sleep schedule to talk or text with family or friends) were associated with sleep-related difficulties. Some ADSMs reported using alcohol (~14%) or exercising prior to bedtime (~34%) in an attempt to fall sleep faster. Conclusions: We identified a high prevalence of sleep-related difficulties in our military sample. Even though most ADSMs used sleep hygiene practices to improve their sleep, some ADSMs used methods not recommended. Improving ADSMs' daily schedule (to include periods for exercising, and protected sleep periods), and further emphasis on sleep hygiene practices may be viable methods to reinforce behaviors promoting healthy sleep and improve performance.

Residual excessive daytime sleepiness in patients with obstructive sleep apnea treated with positive airway pressure therapy.

PURPOSE: Patients with obstructive sleep apnea (OSA) commonly report residual excessive daytime sleepiness (EDS) despite treatment with positive airway pressure (PAP). The present study aimed to determine whether patients presenting with subjective sleepiness after treatment with PAP therapy had objective evidence of residual sleepiness. METHODS: We conducted a retrospective analysis of 29 adults with OSA on PAP therapy who underwent a standardized evaluation for EDS. Patients were evaluated with the Epworth Sleepiness Scale (ESS) and attend an in-lab polysomnogram (PSG) with PAP followed by a multiple sleep latency test (MSLT). RESULTS: Our cohort consisted of 23 men (79%) and 6 women (21%) with a mean age of 40.7 years. All patients were subjectively sleepy with an ESS score of > 10 and met minimal PAP usage of 4 h a night for at least 70% of nights with a residual apnea-hypopnea index (AHI) ≤ 10. On MSLT, 31% of patients had an average sleep onset latency (SOL) < 8 min, 35% had a SOL between 8 and 11 min, and 35% had SOL > 11 min. CONCLUSION: After optimizing PAP therapy and sleep in patients with OSA and residual EDS, the majority were found to have objective findings of an abnormally short SOL on MSLT. This is further evidence that there is a distinct OSA phenotype that will have persistent EDS despite appropriate treatment of their sleep-disordered breathing. Objective testing to quantify the degree of sleepiness is recommended for OSA patients with residual EDS.

The Epworth Sleepiness Scale in Service Members with Sleep Disorders.

INTRODUCTION: Excessive daytime sleepiness affects an estimated 20% of the general population. While the prevalence of sleepiness in the military is largely unknown, it is well established that short sleep duration is endemic. The reasons for this include: the demanding nature of their duties, shift work and 24-hour duty periods, deployments and exigencies of military service as well as sleep disorders. The Epworth Sleepiness Scale (ESS) is the most widely used sleep questionnaire and provides a self-assessment of daytime sleepiness. To date the clinical utility of this questionnaire in differentiating sleep disorders in military patients with sleep disorders has never been evaluated. MATERIALS AND METHODS: The primary aim of this manuscript was to assess if Epworth Sleepiness Scale (ESS) scores differed between military personnel with insomnia, obstructive sleep apnea (OSA), comorbid insomnia/obstructive sleep apnea (COMISA), and a group with neither insomnia nor obstructive sleep apnea (NISA). This study assessed the clinical utility of the ESS in differentiating sleep disorders amongst a sample (N = 488) of U.S. military personnel with insomnia (n = 92), OSA (n = 142), COMISA (n = 221), and a NISA group (n = 33) which served as the control population. RESULTS: In the present sample, 68.4% of service members reported excessive daytime sleepiness (EDS) with an ESS > 10. ESS scores differed between military personnel with COMISA (13.5 ± 4.83) and those with OSA only (11.5 ± 4.08; p < 0.001) and the NISA group (9.46 ± 4.84; p < 0.001). Also, ESS scores differed between patients with insomnia only (13.0 ± 4.84) and the NISA group (p < 0.01). CONCLUSIONS: Overall, the ESS had poor ability to differentiate sleep disorders. In military personnel, the ESS appears elevated in the most common sleep disorders, likely due to their insufficient sleep, and does not help to differentiate OSA from insomnia. Further studies are required to validate this questionnaire and determine an appropriate threshold value for abnormal sleepiness in the military population.

Nightmares in United States Military Personnel With Sleep Disturbances.

STUDY OBJECTIVES: Sleep disturbances are common in United States military personnel. Despite their exposure to combat and trauma, little is known about nightmares in this population. The purpose of this study was to describe the prevalence and associated clinical and polysomnographic characteristics of nightmares in United States military personnel with sleep disturbances. METHODS: Retrospective review of 500 active duty United States military personnel who underwent a sleep medicine evaluation and polysomnography at our sleep center. The Pittsburgh Sleep Quality Index and the Pittsburgh Sleep Quality Index-Addendum were used to characterize clinically significant nightmares. Subjective and objective sleep attributes were compared between groups. RESULTS: At least weekly nightmares were present in 31.2%; yet, only 3.9% reported nightmares as a reason for evaluation. Trauma-related nightmares occurred in 60% of those patients with nightmares. Patients with nightmares had increased sleep onset latency (SOL) and rapid eye movement (REM) sleep latency (mean SOL/REM sleep latency 16.6/145 minutes, P = .02 and P = .01 respectively) compared to those without (mean SOL/REM sleep latency 12.5/126 minutes). The comorbid disorders of depression (P ≤ .01, relative risk [RR] 3.55 [95% CI, 2.52-4.98]), anxiety (P ≤ .01, RR 2.57 [95% CI, 1.93-3.44]), posttraumatic stress disorder (P ≤ .01, RR 5.11 [95% CI, 3.43-7.62]), and insomnia (P ≤ .01, RR 1.59 [95% CI, 1.42-1.79]) were all associated with nightmares. CONCLUSIONS: Clinically significant nightmares are highly prevalent in United States military personnel with sleep disturbances. Nightmares are associated with both subjective and objective sleep disturbances and are frequently comorbid with other sleep and mental health disorders. COMMENTARY: A commentary on this article appears in this issue on page 303.

Elevated tau and interleukin-6 concentrations in adults with obstructive sleep apnea.

Obstructive sleep apnea (OSA) is characterized by apneas and hypopneas that result in hypoxia, cerebral hypoperfusion, endothelial dysfunction, inflammation, and oxidative stress. These pathophysiologic processes likely contribute to neuronal damage. Tau is a protein that stabilizes microtubules and, along with amyloid beta (Aß), is associated with neurodegenerative processes. We sought to determine if tau and other biomarkers of inflammation were related to OSA severity. Concentrations of tau, Aß40, Aß42, c-reactive protein (CRP), TNF-α, interleukin (IL)-6, and IL-10 were measured in blood and compared between participants with moderate-severe OSA (n = 28), those with mild OSA (n = 22), and healthy controls (n = 24). The cohort included relatively young, primarily male active duty military personnel without a history of traumatic brain injury or neurodegenerative disease. Total biomarker concentrations were determined from plasma samples using an ultra-sensitive detection method, Simoa™, and CRP was assayed by ELISA. Total tau and IL-6 concentrations were elevated in participants with moderate-severe OSA, with a mean apnea-hypopnea index (AHI) of 26.1/h, compared to those with mild OSA (mean AHI 8.6/h) and healthy controls (mean AHI 2.1/h). Tau concentrations were also significantly correlated with the AHI (r = 0.342, p = 0.004). Our findings show that tau is elevated in the blood of young patients with moderate-severe OSA, suggesting that this degree of sleep-disordered breathing is a contributing factor in the development of neurodegenerative disorders. The finding of increased IL-6 further suggests that inflammatory biomarkers are present early in the course of this chronic disease.

An Initial Report of Sleep Disorders in Women in the U.S. Military.

INTRODUCTION: Sleep disorders are increasingly recognized in active duty service members (ADSM). While there are multiple studies in male ADSM, there are limited data regarding sleep disorders in women in the military. The purpose of this study was to characterize sleep disorders in female ADSM referred for clinical evaluation to provide a better understanding of this unique population. MATERIALS AND METHODS: We conducted a retrospective review of female ADSM who underwent a sleep medicine evaluation and an attended polysomnogram (PSG). Demographic and polysomnogram variables, as well as medical records, were reviewed. Associated illnesses to include post-traumatic stress disorder, pain disorders, anxiety, and depression, were recorded. RESULTS: The cohort consisted of 101 women. The average age was 33.9 ± 9.0 years and body mass index was 27.3 ± 4.5, with an average Epworth Sleepiness Scale score of 12.9 ± 5.2, and Insomnia Severity Index score of 17.6 ± 5.7. Overall, 36.6% were diagnosed with insomnia only, 14.9% with obstructive sleep apnea (OSA) only, and 34.7% met diagnostic criteria for both insomnia and OSA. The average apnea-hypopnea index for the entire cohort was 5.37 ± 7.04/h whereas it was 10.34 ± 3.14/h for those meeting diagnostic criteria for OSA. The women referred for sleep evaluations had the following rates of associated illnesses: pain disorders (59.4%), anxiety (48.5%), depression (46.5%), and post-traumatic stress disorder (21.8%). For patients with OSA, the relative risk of having post-traumatic stress disorder was 2.72 (95% confidence interval 1.16-6.39). CONCLUSIONS: Women in the U.S. military who have sleep disorders have a high rate of behavioral medicine and pain disorders. Interestingly, nearly 50% of active duty females referred for a sleep study have OSA while not necessarily manifesting the typical signs of obesity or increased age. The reasons for this finding are not completely understood, though factors related to military service may potentially contribute. The findings from our study indicate a need for increased awareness and evaluation of sleep disorders in women in the military, especially those with behavioral medicine disorders.

Discriminating Between Fatigue and Sleepiness in the Naval Operational Environment.

OBJECTIVE: To assess the similarities and differences between reported levels of fatigue and sleepiness as a consequence of working at sea. PARTICIPANTS: 767 crewmembers of a U.S. Navy ship. METHODS: Retrospective analysis of a survey to include questions about demographics, caffeine consumption, sleep adequacy, the Epworth Sleepiness Scale (ESS), and the Fatigue Severity Scale (FSS). RESULTS: ESS scores (8.41 ± 4.66) indicated that 32% of the participants had excessive daytime sleepiness (ESS score > 10), while approximately 7% had an ESS score of 16 or more. FSS scores (average FSS = 3.01 ± 1.37) indicated that 28% of the participants had elevated fatigue (FSS score ≥ 4). Even though ESS and FSS scores were correlated (r = 0.39), their association explained only 15% of the variability observed. In terms of behavioral and lifestyle patterns, crewmembers with elevated fatigue (FSS ≥ 4) reported getting less exercise than those reporting less fatigue. Individuals with excessive sleepiness (ESS > 10) reported higher caffeine consumption. Crewmembers with elevated fatigue and comorbid sleepiness (FSS ≥ 4 and ESS > 10) reported receiving less sleep than other crew members. CONCLUSIONS: These results suggest that subjective fatigue and subjective sleepiness, as measured by the FSS and ESS scales, are distinct constructs and both are consequences of working at sea. The scores on the two scales correlate differentially with behavioral and lifestyle patterns of the crewmembers.