Sleep disturbances among soldiers with combat-related traumatic brain injury

Effects of mTBI with loss of consciousness on neurobehavioral symptoms, depression, and insomnia in former collegiate and NFL football athletes

OBJECTIVE

Considering that diagnostic decisions about mTBI are often predicated on clinical symptom criteria, it is imperative to determine which initial presentation features of mTBI have prognostic significance for identifying those at high risk for long-term functional impairment.

SETTING

Zoom interview Participants: Male, former NCAA Division I, and professional-level National Football League (NFL) athletes (n = 177) between the ages of 27 and 85 (M = 54.1, SD = 14.7).

DESIGN

Cross-sectional case-control. Main Measures: History of mild TBI, history of loss of consciousness (LOC), depression symptoms, insomnia, neurobehavioral symptoms.

RESULTS

Number of mTBI exposures did not predict neurobehavioral symptoms (B = 0.21, SE = 0.18, p = 0.23), but number of mTBI + LOC events did (B = 2.27, SE = 0.64, p = <.001). Further analysis revealed that the number of mTBI + LOC events predicted neurobehavioral symptoms indirectly through both depression (B = 0.85, 95% CI = [0.27, 1.52) and insomnia (B = 0.81, 95% CI = [0.3, 1.4]). Further, the direct effect of mTBI + LOC events on neurobehavioral symptoms became non-significant when depression and insomnia were added to the model (B = 0.78, SE = 0.45, p = 0.08).

CONCLUSIONS

Findings support LOC at time of injury as an important predictor of long-term outcomes. Additionally, results suggest depression and insomnia as potential mediators in the association between mTBI + LOC and neurobehavioral symptoms. These findings provide justification for early depression and insomnia symptom monitoring following mTBI + LOC.

Traumatic brain injury and sleep in military and veteran populations: A literature review

BACKGROUND

Traumatic brain injury (TBI) is a hallmark of wartime injury and is related to numerous sleep wake disorders (SWD), which persist long term in veterans. Current knowledge gaps in pathophysiology have hindered advances in diagnosis and treatment.

OBJECTIVE

We reviewed TBI SWD pathophysiology, comorbidities, diagnosis and treatment that have emerged over the past two decades.

METHODS

We conducted a literature review of English language publications evaluating sleep disorders (obstructive sleep apnea, insomnia, hypersomnia, parasomnias, restless legs syndrome and periodic limb movement disorder) and TBI published since 2000. We excluded studies that were not specifically evaluating TBI populations.

RESULTS

Highlighted areas of interest and knowledge gaps were identified in TBI pathophysiology and mechanisms of sleep disruption, a comparison of TBI SWD and post-traumatic stress disorder SWD. The role of TBI and glymphatic biomarkers and management strategies for TBI SWD will also be discussed.

CONCLUSION

Our understanding of the pathophysiologic underpinnings of TBI and sleep health, particularly at the basic science level, is limited. Developing an understanding of biomarkers, neuroimaging, and mixed-methods research in comorbid TBI SWD holds the greatest promise to advance our ability to diagnose and monitor response to therapy in this vulnerable population.

Effects of Blast-and Impact-Related Concussion on Persistent Sleep Problems

OBJECTIVE

Examine whether concussion mechanism of injury (high-level blast [HLB] vs impact) affects the likelihood of persistent sleep problems in a post-deployment military population.

SETTING

Post-Deployment Health Assessment and Re-Assessment survey records completed upon return from deployment and approximately 6 months later.

PARTICIPANTS

Active duty enlisted US Marines who completed both assessments (N = 64 464).

DESIGN

This retrospective cohort study investigated US Marines deployed between 2008 and 2012. Logistic regression was used to examine persistent sleep problems 6 months after return from deployment.

MAIN MEASURES

Self-reported sleep problems at reassessment were investigated as the outcome. Predictors included HLB-induced concussions (mbTBI vs none), impact-induced concussions (miTBI vs none), occupational risk of low-level blast, probable posttraumatic stress disorder (PTSD), depression, alcohol misuse, sleep problems upon deployment return, and relevant interactions, adjusting for sex and pay grade.

RESULTS

With the exception of sex, all main effects in the model were associated with greater likelihood of reporting persistent sleep problems at reassessment. Sleep problems at return from deployment showed the strongest associations with likelihood of reporting sleep problems at reassessment, followed by mbTBI. The latter was exacerbated by PTSD and depression.

CONCLUSION

mbTBI (vs miTBI) may be more strongly associated with persistent sleep issues that warrant additional monitoring and treatment, particularly among those with probable PTSD and/or depression.

Macroscopic changes in aquaporin-4 underlie blast traumatic brain injury-related impairment in glymphatic function

Mild traumatic brain injury (mTBI) has emerged as a potential risk factor for the development of neurodegenerative conditions such as Alzheimer's disease and chronic traumatic encephalopathy. Blast mTBI, caused by exposure to a pressure wave from an explosion, is predominantly experienced by military personnel and has increased in prevalence and severity in recent decades. Yet the underlying pathology of blast mTBI is largely unknown. We examined the expression and localization of AQP4 in human post-mortem frontal cortex and observed distinct laminar differences in AQP4 expression following blast exposure. We also observed similar laminar changes in AQP4 expression and localization and delayed impairment of glymphatic function that emerged 28 days following blast injury in a mouse model of repetitive blast mTBI. In a cohort of veterans with blast mTBI, we observed that blast exposure was associated with an increased burden of frontal cortical MRI-visible perivascular spaces, a putative neuroimaging marker of glymphatic perivascular dysfunction. These findings suggest that changes in AQP4 and delayed glymphatic impairment following blast injury may render the post-traumatic brain vulnerable to post-concussive symptoms and chronic neurodegeneration.

Hypoglossal Nerve Stimulator in the Active Duty Population: Military Readiness and Satisfaction

INTRODUCTION

Because inadequate sleep impairs mission performance, the U.S. Army regards sleep as a core pillar of soldier readiness. There is an increasing incidence of obstructive sleep apnea (OSA) among active duty (AD) service members, which is a disqualifying condition for initial enlistment. Moreover, a new diagnosis of OSA in the AD population often prompts a medical evaluation board, and if symptomatic OSA proves refractory to treatment, this may result in medical retirement. Hypoglossal nerve stimulator implantation (HNSI) is a newer implantable treatment option, which requires minimal ancillary equipment to function and may provide a useful treatment modality to support AD service members while maintaining readiness in appropriate candidates. Because of a perception among AD service members that HNSI results in mandatory medical discharge, we aimed to evaluate the impact of HNSI on military career progression, maintenance of deployment readiness, and patient satisfaction.

METHODS

The Department of Research Programs at the Walter Reed National Military Medical Center provided institutional review board approval for this project. This is a retrospective, observational study and telephonic survey of AD HNSI recipients. Military service information, demographics, surgical data, and postoperative sleep study results were collected from each patient.Additional survey questions assessed each service member's experience with the device.

RESULTS

Fifteen AD service members who underwent HNSI between 2016 and 2021 were identified. Thirteen subjects completed the survey. The mean age was 44.8 years (range 33-61), and all were men. Six subjects (46%) were officers. All subjects maintained AD status following HNSI yielding 14.5 person-years of continued AD service with the implant. One subject underwent formal assessment for medical retention. One subject transferred from a combat role to a support role. Six subjects have since voluntarily separated from AD service following HNSI. These subjects spent an average of 360 (37-1,039) days on AD service. Seven subjects currently remain on AD and have served for an average of 441 (243-882) days. Two subjects deployed following HNSI. Two subjects felt that HSNI negatively affected their career. Ten subjects would recommend HSNI to other AD personnel. Following HNSI, of the eight subjects with postoperative sleep study data, five achieved surgical success defined as >50% reduction of apnea-hypopnea index and absolute apnea-hypopnea index value of <20.

CONCLUSIONS

Hypoglossal nerve stimulator implantation for AD service members offers an effective treatment modality for OSA, which generally allows for the ability to maintain AD status, however: The impact on deployment readiness should be seriously considered and tailored to each service member based on their unique duties before implantation. Seventy-seven percent of HNSI patients would recommend it to other AD service members suffering from OSA.

The Effect of Concussion Mechanism of Injury on Sleep Problems in Active Duty Service Members Following Deployment

INTRODUCTION

Sleep disruption is pervasive in the military and is generally exacerbated during deployment, partially due to increases in operational tempo and exposure to stressors and/or trauma. In particular, sleep disruption is a commonly reported symptom following deployment-related traumatic brain injury (TBI), though less is known about the prevalence of sleep disturbance as a function of whether the TBI was induced by high-level blast (HLB) or direct impact to the head. TBI assessment, treatment, and prognosis are further complicated by comorbidity with posttraumatic stress disorder (PTSD), depression, and alcohol misuse. Here, we examine whether concussion mechanism of injury is associated with differences in the prevalence of self-reported sleep disturbance following deployment in a large sample of U.S. Marines while accounting for probable PTSD, depression, and alcohol misuse.

MATERIALS AND METHODS

This was a retrospective cohort study of active duty enlisted Marines with a probable concussion (N = 5757) who completed the Post-Deployment Health Assessment between 2008 and 2012. Probable concussion was defined as endorsement of a potentially concussive event with corresponding loss or alteration of consciousness. The presence of concussion-related sleep problems was assessed with a dichotomous item. Probable PTSD, depression, and alcohol misuse were assessed using the Primary Care PTSD Screen, the Patient Health Questionnaire-2, and the Alcohol Use Identification Test-Concise, respectively. Logistic regression models investigated the effects of mechanism of injury (HLB vs. impact), PTSD, depression, and alcohol misuse on the presence of sleep problems, adjusting for sex and pay grade. The study was approved by the Naval Health Research Center Institutional Review Board.

RESULTS

Approximately 41% of individuals with a probable deployment-related concussion reported sleep problems following the event; 79% of concussed individuals reporting both HLB and probable PTSD reported sleep problems. All main effects were significantly associated with sleep disturbance in adjusted models. PTSD showed the strongest association with sleep disturbance (adjusted odds ratio [AOR] = 2.84), followed by depression (AOR = 2.43), HLB exposure (AOR = 2.00), female sex (AOR = 1.63), alcohol misuse (AOR = 1.14), and pay grade (AOR = 1.10). A significant HLB × PTSD interaction emerged (AOR = 1.58), which suggests that sleep disturbance was elevated among those with both HLB-induced (vs. impact-induced) concussions and presence (vs. absence) of PTSD. No other significant interactions emerged.

CONCLUSION

To our knowledge, this is the first study to examine the prevalence of concussion-related sleep complaints following deployment as a function of the mechanism of injury in individuals with and without probable PTSD and depression. Individuals with HLB-induced concussion were twice as likely to report sleep problems as those with an impact-induced concussion. Future work should examine these effects longitudinally with validated measures that assess greater precision of exposure and outcome assessment (e.g., blast intensity and type of sleep disturbance).

Changes in Outpatient Healthcare Utilization and Costs Following Mild Traumatic Brain Injury Among Service Members in the Military Health System by Preexisting Behavioral Health Condition Status

OBJECTIVE

To evaluate changes in healthcare utilization and cost following an index mild traumatic brain injury (mTBI) diagnosis among service members (SMs). We hypothesized that differences in utilization and cost will be observed by preexisting behavioral health (BH) diagnosis status.

SETTING

Direct care outpatient healthcare facilities within the Military Health System.

PARTICIPANTS

A total of 21 984 active-duty SMs diagnosed with an index mTBI diagnosis between 2017 and 2018.

DESIGN

This retrospective study analyzed changes in healthcare utilization and cost in military treatment facilities among SMs with an index mTBI diagnosis. Encounter records 1 year before and after mTBI were assessed; preexisting BH conditions were identified in the year before mTBI.

MAIN MEASURES

Ordinary least squares regressions evaluated difference in the average change of total outpatient encounters and costs among SMs with and with no preexisting BH conditions (eg, posttraumatic stress disorder, adjustment disorder). Additional regressions explored changes in utilization and cost within clinic types (eg, mental health, physical rehabilitation).

RESULTS

There was a 39.5% increase in overall healthcare utilization during the following year, representing a 34.8% increase in total expenditures. Those with preexisting BH conditions exhibited smaller changes in overall utilization (β, -4.9; [95% confidence interval (CI), -6.1 to -3.8]) and cost (β, $-1873; [95% CI, $-2722 to $-1024]), compared with those with no BH condition. The greatest differences were observed in primary care clinics, in which those with prior BH conditions exhibited an average decreased change of 3.2 encounters (95% CI, -3.5 to -3) and reduced cost of $544 (95% CI, $-599 to $-490) compared with those with no prior BH conditions.

CONCLUSION

Despite being higher utilizers of healthcare services both pre- and post-mTBI diagnosis, those with preexisting BH conditions exhibited smaller changes in overall cost and utilization. This highlights the importance of considering prior utilization and cost when evaluating the impact of mTBI and other injury events on the Military Health System.

NSI and PCL-5 Normative Tables for Active Duty Service Members Affected by Traumatic Brain Injury

INTRODUCTION

Many service members (SMs) have been diagnosed with traumatic brain injury. Currently, military treatment facilities do not have access to established normative tables which can assist clinicians in gauging and comparing patient-reported symptoms. The aim of this study is to provide average scores for both the Neurobehavioral Symptom Inventory (NSI) and Posttraumatic Stress Disorder Checklist for DSM-5 (PCL-5) for active duty SMs based upon varying demographic groups.

METHODS

Average scores were calculated for both the NSI and PCL-5 surveys from SMs who attended a military outpatient traumatic brain injury clinic. For this analysis, only the initial surveys for each SM were considered. The identifying demographics included age group, gender, grade, and race.

RESULTS

Four normative tables were created to show the average scores of both the NSI and PCL-5 surveys grouped by demographics. The tables are grouped by Age Group/Gender/Race and Grade/Gender/Race.

CONCLUSION

Clinicians and healthcare administrators can use the scores reported in this study to determine where SM NSI or PCL-5 scores fall within the average for their demographic group.

Glymphatic system: an emerging therapeutic approach for neurological disorders

The functions of the glymphatic system include clearance of the metabolic waste and modulation of the water transport in the brain, and it forms a brain-wide fluid network along with cerebrospinal fluid (CSF) and interstitial fluid (ISF). The glymphatic pathway consists of periarterial influx of CSF, astrocyte-mediated interchange between ISF and CSF supported by aquaporin-4 (AQP4) on the endfeet of astrocyte around the periarterioles, and perivenous efflux of CSF. Finally, CSF is absorbed by the arachnoid granules or flows into the cervical lymphatic vessels. There is growing evidence from animal experiments that the glymphatic system dysfunction is involved in many neurological disorders, such as Alzheimer's disease, stroke, epilepsy, traumatic brain injury and meningitis. In this review, we summarize the latest progress on the glymphatic system and its driving factors, as well as changes in the glymphatic pathway in different neurological diseases. We significantly highlight the likely therapeutic approaches for glymphatic pathway in neurological diseases, and the importance of AQP4 and normal sleep architecture in this process.

Nightmare disorder in active-duty US military personnel

STUDY OBJECTIVES

Military personnel experience high rates of traumatic experiences. Despite this, few studies have examined the presence of nightmare disorder in military personnel. The primary aim of this study was to examine diagnoses of nightmare disorder across the 4 largest branches of the active-duty US military.

DESIGN & PARTICIPANTS

Data and service branch densities used to derive the expected rates of diagnoses of nightmare disorder were drawn from the Defense Medical Epidemiology Database. The branches examined included all active-duty services members in the US Army, Navy, Marine Corps, and Air Force, who served between 2016 and 2021. Single-sample chi-square goodness of fit tests were conducted to examine within-variable differences for military relevant variables.

RESULTS

Between 2016 and 2019, the incidence rates of nightmare disorder (per 10,000 service members) in the US Department of Defense ranged from 11.3 in 2016 to a low of 6.9 in 2018. Service members who were classified as non-white, female, over the age of 35, married, in the Army, and/or a noncommissioned officer, were diagnosed at greater rates relative to their representation in the military population (p < .001).

CONCLUSION

Our findings of higher than expected rates of nightmare disorder in older, senior service members as well as those in the Army align with the known precipitant of nightmares, and trauma. However, the reason for the finding that female and Black service members have higher than expected rates is not readily apparent.

A comprehensive evaluation of insomnia, obstructive sleep apnea and comorbid insomnia and obstructive sleep apnea in US military personnel

STUDY OBJECTIVES

The aim of this study was to characterize the sleep disorders of insomnia, obstructive sleep apnea (OSA), and comorbid insomnia and OSA (COMISA) in active duty military personnel.

METHODS

Prospective observational study of 309 military personnel with a mean age of 37.17 years (SD = 7.27). Participants served in four branches of the U.S. military (47.9% Air Force, 38.8% Army, 11.3% Navy, and 1.9% Marines). Sleep diagnoses were rendered after video-polysomnography and a clinical evaluation. Validated self-report measures assessed insomnia severity, excessive daytime sleepiness, sleep quality, disruptive nocturnal behaviors, nightmare disorder, shift work disorder (SWD), sleep impairment, fatigue, posttraumatic stress disorder (PTSD) symptoms, anxiety, depression, and traumatic brain injury (TBI). General linear models and Pearson chi-square tests were used for between-group differences in data analyses.

RESULTS

Insomnia was diagnosed in 32.7%, OSA in 30.4% and COMISA in 36.9%. Compared to military personnel with OSA alone, those with insomnia only and COMISA had significantly greater insomnia severity, disruptive nocturnal behaviors, sleep-related impairment, rates of nightmare disorder, and poorer sleep quality (all Ps < .05). They also reported greater symptoms of fatigue, PTSD, anxiety, and depression (all Ps < .05). There were no significant differences among the three sleep disorder diagnostic groups on sleepiness, SWD, or TBI.

CONCLUSIONS

Military personnel with insomnia only and COMISA overall report worsened symptoms of sleep disorders, sleep-related impairment, fatigue, and psychiatric disorders than those with OSA. Results highlight the importance of a comprehensive assessment for sleep-related impairment, sleep, and comorbid disorders in military personnel with clinically significant sleep disturbances.

Dexmedetomidine-mediated sleep phase modulation ameliorates motor and cognitive performance in a chronic blast-injured mouse model

Multiple studies have shown that blast injury is followed by sleep disruption linked to functional sequelae. It is well established that improving sleep ameliorates such functional deficits. However, little is known about longitudinal brain activity changes after blast injury. In addition, the effects of directly modulating the sleep/wake cycle on learning task performance after blast injury remain unclear. We hypothesized that modulation of the sleep phase cycle in our injured mice would improve post-injury task performance. Here, we have demonstrated that excessive sleep electroencephalographic (EEG) patterns are accompanied by prominent motor and cognitive impairment during acute stage after secondary blast injury (SBI) in a mouse model. Over time we observed a transition to more moderate and prolonged sleep/wake cycle disturbances, including changes in theta and alpha power. However, persistent disruptions of the non-rapid eye movement (NREM) spindle amplitude and intra-spindle frequency were associated with lasting motor and cognitive deficits. We, therefore, modulated the sleep phase of injured mice using subcutaneous (SC) dexmedetomidine (Dex), a common, clinically used sedative. Dex acutely improved intra-spindle frequency, theta and alpha power, and motor task execution in chronically injured mice. Moreover, dexmedetomidine ameliorated cognitive deficits a week after injection. Our results suggest that SC Dex might potentially improve impaired motor and cognitive behavior during daily tasks in patients that are chronically impaired by blast-induced injuries.

Blast Exposure Dysregulates Nighttime Melatonin Synthesis and Signaling in the Pineal Gland: A Potential Mechanism of Blast-Induced Sleep Disruptions

Blast-induced traumatic brain injury (bTBI) frequently results in sleep-wake disturbances. However, limited studies have investigated the molecular signaling mechanisms underlying these sleep disturbances, and potentially efficacious therapies are lacking. We investigated the levels of melatonin and genes involved in melatonin synthesis pathway in the pineal glands of Sprague Dawley rats exposed to single and tightly coupled repeated blasts during the night and daytime. Rats were exposed to single and tightly coupled repeated blasts using an advanced blast simulator. The plasma, cerebrospinal fluid (CSF), and pineal gland were collected at 6 h, 24 h, or 1 month postblast at two different time points: one during the day (1000 h) and one at night (2200 h). Differential expressions of genes involved in pineal melatonin synthesis were quantified using quantitative real-time polymerase chain reaction (qRT-PCR). Plasma and CSF melatonin levels were assessed using a commercial melatonin ELISA kit. The plasma and CSF melatonin levels showed statistically significant decreases at 6 h and 24 h in the blast-exposed rats euthanized in the night (in dim light), with no significant alterations noted in rats euthanized in the morning (daylight) at all three-time points. Blast-exposed rats showed statistically significant decreases in Tph1, Aanat, Asmt, and Mtnr1b mRNA levels, along with increased Tph2 mRNA, in the pineal gland samples collected at night at 6 h and 24 h. No significant changes in the mRNA levels of these genes were noted at 1 month. These findings imply that the melatonin circadian rhythm is disrupted following blast exposure, which may be a factor in the sleep disturbances that blast victims frequently experience.

Residual sleepiness in veterans with post-traumatic stress disorder and obstructive sleep apnea

PURPOSE

The causes of residual excessive sleepiness (RES) in patients with post-traumatic stress disorder (PTSD) and obstructive sleep apnea (OSA) are multifactorial and modulated by comorbid conditions. The aim of the present study was to elucidate clinical and polysomnographic determinants of RES in continuous positive airway pressure (CPAP)-adherent OSA veterans with PTSD.

METHODS

The study protocol consisted of a retrospective analysis of consecutive cases of patients with PTSD who presented to the Veterans Affairs sleep clinics with adequately treated OSA between June 1, 2017 and October 15, 2021. Based on the Epworth Sleepiness Scale (ESS), patients were categorized into RES (ESS ≥ 11) and no RES (ESS < 11) groups. Demographic and PSG data were subjected to univariate and multivariate analyses to ascertain predictive factors of RES.

RESULTS

Out of 171 veterans with PTSD who were adherent to CPAP, 59 (35%) continued to experience RES. The RES group had a decrease in mean ESS score of 1.2 ± 4.5 after CPAP treatment compared with 4.6 ± 4.9 for the no RES group (< 0.001). A dose-response was observed between CPAP use and RES (p = 0.003). Multivariate regression analysis identified higher baseline ESS (OR 1.30; 95% CI 1.16-1.44), greater percentage of time spent in REM sleep (OR 0.91; 95% CI 0.85-0.96), CPAP use less than 6 h (OR 2.82; 95% CI 1.13-7.01), and a positive screen for depression (OR 1.69; 95% CI 1.03-4.72) as independent predictors of RES in patients with PTSD and OSA.

CONCLUSION

RES is highly prevalent in patients with PTSD and OSA despite adherence to CPAP and is independently associated with percentage time spent in REM, duration of CPAP utilization, and symptoms of depression.

Sleep Disorders in Traumatic Brain Injury

SUMMARY

Sleep disorders are common after traumatic brain injury (TBI). This study will review the spectrum and proposed mechanisms of TBI-associated sleep disorders and discuss the clinical approach to diagnosis and management of them. Disordered and fragmented sleep with insomnia and daytime sleepiness is very common after TBI. Sleep disruption contributes to morbidity and neurocognitive and neurobehavioral deficits and prolongs the recovery phase after injury. Early recognition and correction of these problems may limit the secondary effects of TBI and improve patient outcomes. Evaluating sleep disorders in TBI should be an important component of TBI assessment and management. Finally, newer research techniques for early diagnosis, prognosis, and improved outcomes after TBI will also be addressed.

Glymphatic System Dysfunction in Central Nervous System Diseases and Mood Disorders

The glymphatic system, a recently discovered macroscopic waste removal system in the brain, has many unknown aspects, especially its driving forces and relationship with sleep, and thus further explorations of the relationship between the glymphatic system and a variety of possible related diseases are urgently needed. Here, we focus on the progress in current research on the role of the glymphatic system in several common central nervous system diseases and mood disorders, discuss the structural and functional abnormalities of the glymphatic system which may occur before or during the pathophysiological progress and the possible underlying mechanisms. We emphasize the relationship between sleep and the glymphatic system under pathological conditions and summarize the common imaging techniques for the glymphatic system currently available. The perfection of the glymphatic system hypothesis and the exploration of the effects of aging and endocrine factors on the central and peripheral regulatory pathways through the glymphatic system still require exploration in the future.

Associations between residual hyperarousal and insomnia symptoms in veterans following a 2-week intensive outpatient program for posttraumatic stress disorder

Many returning military service members and veterans who were deployed following the September 11, 2001, terrorist attacks (9/11) suffer from posttraumatic stress disorder (PTSD) and insomnia. Although intensive treatment programs for PTSD have shown promise in the treatment of PTSD symptoms, recent research has demonstrated that sleep disturbance shows little improvement following intensive trauma-focused treatment. The aim of the present study was to evaluate changes in self-reported insomnia symptoms among veterans and service members following participation in a 2-week intensive program for PTSD. We further aimed to investigate if residual PTSD symptoms, specifically hyperarousal, were associated with residual insomnia symptoms. Participants (N = 326) completed self-report assessments of insomnia, PTSD symptoms, and depressive symptoms at pre- and posttreatment. At pretreatment, 73.9% of participants (n = 241) met the criteria for moderate or severe insomnia, whereas at posttreatment 67.7% of participants (n = 203) met the criteria. Results of paired t tests demonstrated statistically significant differences between pre- and posttreatment Insomnia Severity Index scores; however, the effect size was small, d = 0.34. Analyses revealed that posttreatment hyperarousal symptoms were associated with posttreatment insomnia. These findings suggest that although an intensive program for service members and veterans with PTSD may significantly reduce insomnia symptoms, clinically meaningful residual insomnia symptoms remain. Further research is warranted to elucidate the association between residual hyperarousal and insomnia symptoms following intensive trauma-focused treatment.

The Bidirectional Link Between Sleep Disturbances and Traumatic Brain Injury Symptoms: A Role for Glymphatic Dysfunction?

Mild traumatic brain injury (mTBI), often referred to as concussion, is a major cause of morbidity and mortality worldwide. Sleep disturbances are common after mTBI. Moreover, subjects who develop subjective sleep complaints after mTBI also report more severe somatic, mental health, and cognitive impairment and take longer to recover from mTBI sequelae. Despite many previous studies addressing the role of sleep in post-mTBI morbidity, the mechanisms linking sleep to recovery after mTBI remain poorly understood. The glymphatic system is a brainwide network that supports fluid movement through the cerebral parenchyma and the clearance of interstitial solutes and wastes from the brain. Notably, the glymphatic system is active primarily during sleep. Clearance of cellular byproducts related to somatic, mental health, and neurodegenerative processes (e.g., amyloid-β and tau, among others) depends in part on intact glymphatic function, which becomes impaired after mTBI. In this viewpoint, we review the current knowledge regarding the association between sleep disturbances and post-mTBI symptoms. We also discuss the role of glymphatic dysfunction as a potential link between mTBI, sleep disruption, and posttraumatic morbidity. We outline a model where glymphatic dysfunction and sleep disruption caused by mTBI may have an additive effect on waste clearance, leading to cerebral dysfunction and impaired recovery. Finally, we review the novel techniques being developed to examine glymphatic function in humans and explore potential interventions to alter glymphatic exchange that may offer a novel therapeutic approach to those experiencing poor sleep and prolonged symptoms after mTBI.

Evaluation of Machine Learning Techniques to Predict the Likelihood of Mental Health Conditions Following a First mTBI

Objective

Limited research has evaluated the utility of machine learning models and longitudinal data from electronic health records (EHR) to forecast mental health outcomes following a traumatic brain injury (TBI). The objective of this study is to assess various data science and machine learning techniques and determine their efficacy in forecasting mental health (MH) conditions among active duty Service Members (SMs) following a first diagnosis of mild traumatic brain injury (mTBI).

Materials and Methods

Patient demographics and encounter metadata of 35,451 active duty SMs who have sustained an initial mTBI, as documented within the EHR, were obtained. All encounter records from a year prior and post index mTBI date were collected. Patient demographics, ICD-9-CM and ICD-10 codes, enhanced diagnostic related groups, and other risk factors estimated from the year prior to index mTBI were utilized to develop a feature vector representative of each patient. To embed temporal information into the feature vector, various window configurations were devised. Finally, the presence or absence of mental health conditions post mTBI index date were used as the outcomes variable for the models.

Results

When evaluating the machine learning models, neural network techniques showed the best overall performance in identifying patients with new or persistent mental health conditions post mTBI. Various window configurations were tested and results show that dividing the observation window into three distinct date windows [−365:−30, −30:0, 0:14] provided the best performance. Overall, the models described in this paper identified the likelihood of developing MH conditions at [14:90] days post-mTBI with an accuracy of 88.2%, an AUC of 0.82, and AUC-PR of 0.66.

Discussion

Through the development and evaluation of different machine learning models we have validated the feasibility of designing algorithms to forecast the likelihood of developing mental health conditions after the first mTBI. Patient attributes including demographics, symptomatology, and other known risk factors proved to be effective features to employ when training ML models for mTBI patients. When patient attributes and features are estimated at different time window, the overall performance increase illustrating the importance of embedding temporal information into the models. The addition of temporal information not only improved model performance, but also increased interpretability and clinical utility.

Conclusion

Predictive analytics can be a valuable tool for understanding the effects of mTBI, particularly when identifying those individuals at risk of negative outcomes. The translation of these models from retrospective study into real-world validation models is imperative in the mitigation of negative outcomes with appropriate and timely interventions.

Poor Sleep Quality is Linked to Elevated Extracellular Vesicle-Associated Inflammatory Cytokines in Warfighters With Chronic Mild Traumatic Brain Injuries

Background: Elevations of inflammatory cytokine levels occur immediately after mild traumatic brain injury (mTBI) and can persist for years. These elevations have been associated with neuropsychological outcomes, including depression and PTSD symptoms. Sleep disorders, another common sequelae of mTBI, are independently associated with inflammation in otherwise healthy individuals. However, whether sleep and inflammation are linked in chronic mTBI has not been reported.

Methods: A retrospective cross-sectional cohort of warfighters was used to investigate the hypothesis that inflammation may be linked to sleep quality in chronic mTBI. Clinical history, peripheral blood samples, and sleep quality scores were collected from 182 warfighters (n = 138 mTBI; n = 44 controls) during enrollment in the Chronic Effects of Neurotrauma Consortium study. Biomarkers of inflammation (IL-6, IL-10, TNFα cytokines) from plasma and plasma-derived extracellular vesicles (EVs) were quantified using single molecule array. Relationships between sleep quality and cytokine levels were assessed, controlling for age, sex, and BMI. Using clinical cutoff scores for sleep quality, mTBI patients were then divided into “good” and “poor” sleepers and cytokine levels compared between groups.

Results: In mTBI participants, sleep quality was significantly associated with EV levels of IL-10 [ß (SE) = 0.11 (0.04), p = 0.01] and TNFα [ß (SE) = 0.07 (0.03), p < 0.01]. When divided according to “good” versus “poor” sleepers, those reporting poor sleep had significantly elevated EV IL-10 compared to those reporting good sleep [ß (SE) = 0.12 (0.04), p < 0.01]. Plasma-derived associations were not significant. No associations were found between sleep quality and cytokine levels in controls.

Conclusion: These results suggest a significant relationship between sleep quality and chronic inflammation in mTBI patients. Clinically, mTBI patients with a high likelihood of sleep disorders demonstrate elevated levels of inflammatory cytokines. Signal from EVs, though smaller in magnitude, may have stronger clinical associations than from plasma. Sleep-focused interventions may also serve to regulate chronic inflammatory processes in these patients. Larger prospective studies are needed to investigate the mechanisms and therapeutic implications of the likely bi-directional relationship between sleep and inflammation following mTBI.

Correlations Between the Neurobehavioral Symptom Inventory and Other Commonly Used Questionnaires for Traumatic Brain Injury

OBJECTIVE

To evaluate the correlations between the Neurobehavioral Symptom Inventory (NSI) and other questionnaires commonly administered within military traumatic brain injury clinics.

SETTING

Military outpatient traumatic brain injury clinics.

PARTICIPANTS

In total, 15,428 active duty service members who completed 24,162 NSI questionnaires between March 2009 and May 2020.

DESIGN

Observational retrospective analysis of questionnaires collected as part of standard clinical care.

MAIN MEASURES

NSI, Post-Traumatic Stress Disorder Checklist for DSM-5 and Military Version, Patient Health Questionnaire (PHQ), Generalized Anxiety Disorder, Headache Impact Test (HIT-6), Insomnia Severity Index (ISI), Epworth Sleepiness Scale (ESS), Activities-Specific Balance Confidence Scale (ABC), Dizziness Handicap Inventory (DHI), Alcohol Use Disorders Identification Test (AUDIT), and the World Health Organization Quality of Life Instrument-Abbreviated Version. Only questionnaires completed on the same date as the NSI were examined.

RESULTS

The total NSI score was moderately to strongly correlated with all questionnaires except for the AUDIT. The strongest correlation was between the NSI Affective Score and the PHQ9 (r  = 0.86). The NSI Vestibular Score was moderately correlated with the ABC (r = -0.55) and strongly correlated with the DHI (r = 0.77). At the item level, the HIT-6 showed strong correlation with NSI headache (r = 0.80), the ISI was strongly correlated with NSI difficulty sleeping (r = 0.63), and the ESS was moderately correlated with NSI fatigue (r = 0.39).

CONCLUSION

Clinicians and healthcare administrators can use the correlations reported in this study to determine if questionnaires add incremental value for their clinic as well as to make more informed decisions regarding which questionnaires to administer.

Long-Term Effects of Low-Intensity Blast Non-Inertial Brain Injury on Anxiety-Like Behaviors in Mice: Home-Cage Monitoring Assessments

Mild traumatic brain injury induced by low-intensity blast (LIB) exposure poses concerns in military personnel. Using an open-field, non-inertial blast model and assessments by conventional behavioral tests, our previous studies revealed early-phase anxiety-like behaviors in LIB-exposed mice. However, the impact of LIB upon long-term anxiety-like behaviors requires clarification. This study applied a highly sensitive automated home-cage monitoring (HCM) system, which minimized human intervention and environmental changes, to assess anxiety-like responses in mice 3 months after LIB exposure. Initial assessment of 72-h spontaneous activities in a natural cage condition over multiple light and dark phases showed altered sheltering behaviors. LIB-exposed mice exhibited a subtle, but significantly decreased, duration of short shelter visits as compared to sham controls. Other measured responses between LIB-exposed mice and sham controls were insignificant. When behavioral assessments were performed in a challenged condition using an aversive spotlight, LIB-exposed mice demonstrated a significantly higher frequency of movements of shorter distance and duration per movement. Taken together, these findings demonstrated the presence of chronic anxiety-like behaviors assessed by the HCM system under both natural and challenged conditions in mice occurring post-LIB exposure. This model thus provides a platform to test for screening and interventions on anxiety disorders occurring after LIB non-inertial brain injury.

Obstructive sleep apnea among survivors of combat-related traumatic injury: a retrospective cohort study

STUDY OBJECTIVES

Obstructive sleep apnea is prevalent among military members despite fewer traditional risk factors. We sought to determine the incidence and longitudinal predictors of obstructive sleep apnea in a large population of survivors of combat-related traumatic injury and a matched control group.

METHODS

Retrospective cohort study of military service members deployed to conflict zones from 2002-2016 with longitudinal follow-up in the Veterans Affairs and Military Health Systems. Two cohorts of service members were developed: (1) those who sustained combat injuries and (2) matched, uninjured participants.

RESULTS

17,570 service members were retrospectively analyzed for a median of 8.4 years. After adjustment, traumatic brain injury (hazard ratio [HR] 1.39, 95% confidence interval [CI] 1.20-1.60), posttraumatic stress disorder (HR 1.24, 95% CI 1.05-1.46), depression (HR 1.52, 95% CI 1.30-1.79), anxiety (HR 1.40, 95% CI 1.21-1.62), insomnia (HR 1.71, 95% CI 1.44-2.02), and obesity (HR 2.40, 95% CI 2.09-2.74) were associated with development of obstructive sleep apnea. While combat injury was associated with obstructive sleep apnea in the univariate analysis (HR 1.25, 95% CI 1.17-1.33), the direction of this association was reversed in the multivariable model (HR 0.74, 95% CI 0.65-0.84). In a nested analysis, this was determined to be due to the effect of mental health diagnoses.

CONCLUSIONS

The incidence of obstructive sleep apnea is higher among injured service members (29.1 per 1,000 person-years) compared to uninjured service members (23.9 per 1,000 person-years). This association appears to be driven by traumatic brain injury and the long-term mental health sequelae of injury.

CITATION

Haynes ZA, Stewart IJ, Poltavskiy EA, et al. Obstructive sleep apnea among survivors of combat-related traumatic injury: a retrospective cohort study. J Clin Sleep Med. 2022;18(1):171-179.

Prevalence and predictors of insomnia and sleep medication use in a large tri-service US military sample

OBJECTIVE

The presence of insomnia in the general military population is not well known. This study aimed to determine the prevalence of probable clinical insomnia and identify factors leading to new-onset insomnia and/or sleep medication use in a large military population.

DESIGN

Cross-sectional and longitudinal analyses of a prospective cohort study.

PARTICIPANTS

A tri-service US military and veteran cohort (sample range 99,383-137,114).

MEASUREMENTS

Participants were surveyed in 2013 (Time 1 [T1]) and 2016 (Time 2 [T2]) using the clinically validated Insomnia Severity Index. The prevalence of insomnia and sleep medication use was quantified at both times. Multivariable models identified military factors associated with new-onset insomnia and/or sleep medication use while adjusting for covariates.

RESULTS

The prevalence of insomnia at T1 and T2 was 16.3% and 11.2%, respectively. New-onset insomnia at T2 was reported by 6.0% of participants screening negative at T1; risk factors included Army service, combat deployment experience, and separation from military service. The prevalence of sleep medication use at T1 and T2 was 23.1% and 25.1%, respectively. Sleep medication use at T2 was newly-reported by 17.1% of participants not reporting sleep medication use at T1; risk factors included number of deployments and having a healthcare occupation.

CONCLUSIONS

The prevalence of probable clinical insomnia in this large general military population is within the range of previous reports in military and civilian populations. Certain military factors that predict new-onset insomnia and/or sleep medication use should be considered when designing and implementing sleep interventions in military populations.

Dementia in military and veteran populations: a review of risk factors-traumatic brain injury, post-traumatic stress disorder, deployment, and sleep

The military population face a unique set of risk factors that may increase the risk of being diagnosed with dementia. Traumatic brain injury (TBI) and post-traumatic stress disorder (PTSD) have a higher prevalence in this group in comparison to the civilian population. By delving into the individual relationships between TBI and dementia, and PTSD and dementia, we are able to better explore dementia in the military and veteran populations. While there are some inconsistencies in results, the TBI-dementia association has become more widely accepted. Moderate-to-severe TBI has been found to increase the risk of being diagnosed with Alzheimer's disease. A correlation between PTSD and dementia has been established, however, whether or not it is a causal relationship remains unclear. Factors such as blast, combat and chemical exposure may occur during a deployment, along with TBI and/or PTSD diagnosis, and can impact the risk of dementia. However, there is a lack of literature exploring the direct effects of deployment on dementia risk. Sleep problems have been observed to occur in those following TBI, PTSD and deployment. Poor sleep has been associated with possible dementia risk. Although limited studies have focused on the link between sleep and dementia in military and veteran populations, sleep is a valuable factor to study due to its association and interconnection with other military/veteran factors. This review aims to inform of various risk factors to the cognitive health of military members and veterans: TBI, PTSD, deployment, and sleep.

Compounding Effects of Traumatic Brain Injury, Military Status, and Other Factors on Pittsburgh Sleep Quality Index: A Meta-analysis

INTRODUCTION

Traumatic brain injury (TBI) or concussion is a known risk factor for multiple adverse health outcomes, including disturbed sleep. Although prior studies show adverse effects of TBI on sleep quality, its compounding effect with other factors on sleep is unknown. This meta-analysis aimed to quantify the effects of TBI on subjective sleep quality in the context of military status and other demographic factors.

MATERIALS AND METHODS

A programmatic search of PubMed database from inception to June 2020 was conducted to identify studies that compared subjective sleep quality measured using Pittsburgh Sleep Quality Index (PSQI) in individuals with TBI relative to a control group. The meta-analysis included group-wise standard mean difference (SMD) and 95% CI. Pooled means and SDs were obtained for TBI and non-TBI groups with and without military service, and meta-regression was conducted to test for group effects. Exploratory analysis was performed to test for the effect of TBI, non-head injury, military status, sex, and age on sleep quality across studies.

RESULTS

Twenty-six articles were included, resulting in a combined total of 5,366 individuals (2,387 TBI and 2,979 controls). Overall, individuals with TBI self-reported poorer sleep quality compared to controls (SMD = 0.63, 95% CI: 0.45 to 0.80). Subgroup analysis revealed differences in the overall effect of TBI on PSQI, with a large effect observed in the civilian subgroup (SMD: 0.80, 95% CI: 0.57 to 1.03) and a medium effect in the civilian subgroup with orthopedic injuries (SMD: 0.40, 95% CI: 0.13 to 0.65) and military/veteran subgroup (SMD: 0.43, 95% CI: 0.14 to 0.71). Exploratory analysis revealed that age and history of military service significantly impacted global PSQI scores.

CONCLUSIONS

Poor sleep quality in TBI cohorts may be due to the influence of multiple factors. Military/veteran samples had poorer sleep quality compared to civilians even in the absence of TBI, possibly reflecting unique stressors associated with prior military experiences and the sequelae of these stressors or other physical and/or psychological traumas that combine to heightened vulnerability. These findings suggest that military service members and veterans with TBI are particularly at a higher risk of poor sleep and its associated adverse health outcomes. Additional research is needed to identify potential exposures that may further heighten vulnerability toward poorer sleep quality in those with TBI across both civilian and military/veteran populations.

Risk Factors Associated With the Prescription of Opioids Among Service Members Following a First Mild Traumatic Brain Injury

OBJECTIVE

To evaluate factors impacting opioid receipt among active-duty service members (SMs) following a first mild traumatic brain injury (mTBI).

SETTING

Active-duty SMs receiving care within the Military Health System.

PARTICIPANTS

In total, 14 757 SMs who have sustained an initial mTBI, as documented within electronic health records (EHRs), between 2016 and 2017.

DESIGN

A retrospective analysis of EHR metadata.

MAIN MEASURES

Multivariable logistic regression assessed factors impacting opioid receipt and initiation. Factors include demographics, military characteristics, and preexisting clinical conditions, including prior opioid prescription.

RESULTS

Of the sample population, 33.4% (n = 4927) were prescribed opioids after their initial mTBI, of which, 60.6% (n = 2985) received opioids for the first time following injury. Significant risk factors associated with the increased probability of opioid receipt included age, gender, and preexisting behavioral health and musculoskeletal conditions. Military characteristics also exhibited changes in the probability of opioid receipt, both among initiation and new prescription. No changes were observed among race, nor among those with preexisting headaches or migraines.

CONCLUSION

Despite concerns about the negative impact on recovery, the prescribing of opioids is common in this population of active-duty SMs first diagnosed with an mTBI. As several demographic and preexisting health conditions are factors in the receipt of opioids post-mTBI, the entire medical history of these patients should be considered prior to prescription. Understanding these factors may further inform policy for opioid use in the Military Health System.

Incidence of insomnia and obstructive sleep apnea in active duty United States military service members

STUDY OBJECTIVES

Epidemiologic studies of obstructive sleep apnea (OSA) and insomnia in the U.S. military are limited. The primary aim of this study was to report and compare OSA and insomnia diagnoses in active duty the United States military service members.

METHOD

Data and service branch densities used to derive the expected rates of diagnoses on insomnia and OSA were drawn from the Defense Medical Epidemiology Database. Single sample chi-square goodness of fit tests and independent samples t-tests were conducted to address the aims of the study.

RESULTS

Between 2005 and 2019, incidence rates of OSA and insomnia increased from 11 to 333 and 6 to 272 (per 10,000), respectively. Service members in the Air Force, Navy, and Marines were diagnosed with insomnia and OSA below expected rates, while those in the Army had higher than expected rates (p < .001). Female service members were underdiagnosed in both disorders (p < .001). Comparison of diagnoses following the transition from ICD 9 to 10 codes revealed significant differences in the amounts of OSA diagnoses only (p < .05).

CONCLUSION

Since 2005, incidence rates of OSA and insomnia have markedly increased across all branches of the U.S. military. Despite similar requirements for overall physical and mental health and resilience, service members in the Army had higher rates of insomnia and OSA. This unexpected finding may relate to inherent differences in the branches of the military or the role of the Army in combat operations. Future studies utilizing military-specific data and directed interventions are required to reverse this negative trend.

Poor sleep correlates with biomarkers of neurodegeneration in mild traumatic brain injury patients: a CENC study

STUDY OBJECTIVES

Sleep disorders affect over half of mild traumatic brain injury (mTBI) patients. Despite evidence linking sleep and neurodegeneration, longitudinal TBI-related dementia studies have not considered sleep. We hypothesized that poor sleepers with mTBI would have elevated markers of neurodegeneration and lower cognitive function compared to mTBI good sleepers and controls. Our objective was to compare biomarkers of neurodegeneration and cognitive function with sleep quality in warfighters with chronic mTBI.

METHODS

In an observational warfighters cohort (n = 138 mTBI, 44 controls), the Pittsburgh Sleep Quality Index (PSQI) was compared with plasma biomarkers of neurodegeneration and cognitive scores collected an average of 8 years after injury.

RESULTS

In the mTBI cohort, poor sleepers (PSQI ≥ 10, n = 86) had elevated plasma neurofilament light (NfL, x̅ = 11.86 vs 7.91 pg/mL, p = 0.0007, d = 0.63) and lower executive function scores by the categorical fluency (x̅ = 18.0 vs 21.0, p = 0.0005, d = -0.65) and stop-go tests (x̅ = 30.1 vs 31.1, p = 0.024, d = -0.37). These findings were not observed in controls (n = 44). PSQI predicted NfL (beta = 0.22, p = 0.00002) and tau (beta = 0.14, p = 0.007), but not amyloid β42. Poor sleepers showed higher obstructive sleep apnea (OSA) risk by STOP-BANG scores (x̅ = 3.8 vs 2.7, p = 0.0005), raising the possibility that the PSQI might be partly secondary to OSA.

CONCLUSIONS

Poor sleep is linked to neurodegeneration and select measures of executive function in mTBI patients. This supports implementation of validated sleep measures in longitudinal studies investigating pathobiological mechanisms of TBI related neurodegeneration, which could have therapeutic implications.

Risk factors of persistent insomnia among survivors of traumatic injury: a retrospective cohort study

STUDY OBJECTIVES

Insomnia is a diagnosis with broad health and economic implications that has been increasingly recognized in military service members. This trend was concurrent with an increase in traumatic wartime injuries. Accordingly, we sought to determine longitudinal predictors of persistent insomnia in combat veterans who sustained traumatic injuries.

METHODS

Retrospective cohort study of service members deployed to conflict zones from 2002-2016, with longitudinal follow-up in the Veterans Affairs and Military Health Systems. Two cohorts were derived: 1) service members who sustained traumatic injuries and 2) an age, sex, and service component matched cohort of uninjured service members who deployed to a combat zone. Insomnia was defined using International Classification of Diseases Ninth Revision or International Classification of Diseases Tenth Revision Clinical Modification codes.

RESULTS

The final population of 17,374 service members was followed from date of injury (or date of matched participant's injury) for a median of 8.4 (IQR 5.3-10.7) years. Service members with traumatic injury were at significantly greater risk of developing insomnia than uninjured service members (HR=1.43, 95% CI 1.30-1.58) after adjustment. Traumatic brain injury (TBI) was associated with insomnia when compared to patients without TBI in the multivariable model: mild/unclassified TBI (HR=2.07, 95% CI 1.82-2.35), moderate/severe/penetrating TBI (HR=2.43, 95% CI 2.06-2.86). Additionally, burn injury (HR=1.95, 95% CI 1.47-2.59) and amputation (HR=1.61, 95% CI 1.26-2.06) significantly increased the risk of a diagnosis.

CONCLUSIONS

Traumatic injuries significantly predicted a diagnosis of insomnia after controlling for mental health disorders. Our findings strongly suggest the need for long-term surveillance of sleep disorders in trauma survivors.

Traumatic Brain Injury and Incidence Risk of Sleep Disorders in Nearly 200,000 US Veterans

OBJECTIVE

To test the hypothesis that veterans with traumatic brain injury (TBI) have an increased subsequent risk of sleep disorders, we studied the longitudinal association between TBI and incident sleep disorders in nearly 200,000 veterans.

METHODS

We performed a cohort study of all patients diagnosed with a TBI in the Veterans Health Administration system from October 1, 2001, to September 30, 2015, who were age-matched 1:1 to veterans without TBI. Veterans with prevalent sleep disorders at baseline were excluded. Development of sleep disorders was defined as any inpatient or outpatient diagnosis of sleep apnea, hypersomnia, insomnia, or sleep-related movement disorders based on ICD-9 codes after the first TBI diagnosis or the random selection date for those without TBI. We restricted the analysis to those with at least 1 year of follow-up. We used Cox proportional hazards models to examine the association between TBI and subsequent risk of sleep disorders.

RESULTS

The study included 98,709 veterans with TBI and 98,709 age-matched veterans without TBI (age 49 ± 20 years). After an average follow-up of 5 (1-14) years, 23,127 (19.6%) veterans developed sleep disorders. After adjustment for demographics, education, income, and medical and psychiatric conditions, those who had TBI compared to those without TBI were 41% more likely to develop any sleep disorders (hazard ratio 1.41 [95% confidence interval 1.37-1.44]), including sleep apnea (1.28 [1.24-1.32]), insomnia (1.50 [1.45-1.55]), hypersomnia (1.50 [1.39-1.61]), and sleep-related movement disorders (1.33 [1.16-1.52]). The association was stronger for mild TBIs, did not differ appreciably by presence of posttraumatic stress disorder, and remained after a 2-year time lag.

CONCLUSION

In 197,418 veterans without sleep disorders, those with diagnosed TBI had an increased risk of incident sleep disorders over 14 years. Improved prevention and long-term management strategies for sleep are needed for veterans with TBI.

Efficacy of an Interdisciplinary Intensive Outpatient Program in Treating Combat-Related Traumatic Brain Injury and Psychological Health Conditions

Background: Since 2000, over 413,000 US service members (SM) experienced at least one traumatic brain injury (TBI), and 40% of those with in-theater TBIs later screened positive for comorbid psychological health (PH) conditions, including post-traumatic stress disorder (PTSD), depression, and anxiety. Many SMs with these persistent symptoms fail to achieve a recovery that results in a desirable quality of life or return to full duty. Limited information exists though to guide treatment for SMs with a history of mild TBI (mTBI) and comorbid PH conditions. This report presents the methods and outcomes of an interdisciplinary intensive outpatient program (IOP) in the treatment of SMs with combat-related mTBI and PH comorbidities. The IOP combines conventional rehabilitation therapies and integrative medicine techniques with the goal of reducing morbidity in multiple neurological and behavioral health domains and enhancing military readiness. Methods: SMs (n = 1,456) with residual symptoms from mTBI and comorbid PH conditions were treated in a 4-week IOP at the National Intrepid Center of Excellence (NICoE) at Walter Reed National Military Medical Center (WRNMMC). The IOP uses an interdisciplinary, holistic, and patient-centric rehabilitative care model. Interdisciplinary teams provide a diagnostic workup of neurological, psychiatric, and existential injuries, and from these assessments, individualized care plans are developed. Treatment response was assessed using the Neurobehavioral Symptom Inventory (NSI), PTSD Checklist-Military Version (PCL-M), Satisfaction With Life Scale (SWLS), Patient Health Questionnaire-9 (PHQ-9), Generalized Anxiety Disorder-7 (GAD-7), Epworth Sleepiness Scale (ESS), and Headache Impact Test-6 (HIT-6) and administered at admission, discharge, and at 1, 3, and 6 months post-discharge. Findings: Following treatment in the IOP, the symptomatic patients had statistically significant and clinically meaningful improvements across all outcome measures. The largest effect size was seen with GAD-7 (r = 0.59), followed by PHQ-8 (r = 0.56), NSI (r = 0.55), PCL-M (r = 0.52), ESS (r = 0.50), SWLS (r = 0.49), and HIT-6 (r = 0.42). In cross-sectional follow ups, the significant improvements were sustained at 1, 3, and 6 months post-discharge. Interpretation: This report demonstrates that an interdisciplinary IOP achieves significant and sustainable symptom recovery in SMs with combat-related mTBI and comorbid PH conditions and supports the further study of this model of care in complex medical conditions.

Sleep disorders in traumatic brain injury

The purpose of the review is to collect the most relevant current literature on the mechanisms of normal sleep and sleep disorders associated with traumatic brain injury (TBI), to discuss the most frequent conditions and the evidence on their possible treatments and future research. Sleep disorders are extremely prevalent after TBI (30-84%). Insomnia and circadian rhythm disorders are the most frequent disorders among the population that has suffered mild TBI, while hypersomnolence disorders are more frequent in populations that have suffered moderate and severe TBI. The syndrome of obstructive sleep apnea and restless leg syndrome are also very frequent in these patients; and patients exposed to multiple TBIs (war veterans) are especially susceptible to sleep disorders. The treatment of these disorders requires taking into account the particularities of these patients. In conclusion, diagnosis and treatment of sleep disorders should become part of routine clinical practice and cease to be anecdotal (as it is today) in patients with TBI. In addition, it is necessary to continue carrying out research that reveals the best therapeutic approach to these patients.

Obstructive Sleep Apnea Risk Is Associated with Cognitive Impairment after Controlling for Mild Traumatic Brain Injury History: A Chronic Effects of Neurotrauma Consortium Study

The contribution of sleep disturbance to persistent cognitive symptoms following a mild traumatic brain injury (mTBI) remains unclear. Obstructive sleep apnea (OSA) is very common, yet its relationship between risk factors for developing OSA and cognitive performance in those with history of mTBI has not been investigated. The current study examined OSA risk levels and its association with cognitive performance in 391 combat-exposed, post-911 veterans and service members (median age = 37 years) enrolled in the Chronic Effects of Neurotrauma Consortium (CENC) prospective multi-center study. Participants included those with and without mTBI (n = 326 and 65, respectively). When using clinical cut-offs, those with history of mTBI were more likely to be categorized as high risk for OSA (mTBI positive = 65% vs. mTBI negative = 51%). After adjustment for TBI status and demographic variables, increased OSA risk was significantly associated with worse performance on measures of complex processing speed and executive functioning (Wechsler Adult Intelligence Scale Fourth Edition Coding, Trail Making Test, part B) and greater symptom burden (Neurobehavioral Symptom Inventory). Thus, OSA, a modifiable behavioral health factor, likely contributes to cognitive performance following mTBI. Accordingly, OSA serves as a potential point of intervention to improve clinical and cognitive outcomes after injury.

Sleep disorders in traumatic brain injury

The purpose of the review is to collect the most relevant current literature on the mechanisms of normal sleep and sleep disorders associated with traumatic brain injury (TBI), to discuss the most frequent conditions and the evidence on their possible treatments and future research. Sleep disorders are extremely prevalent after TBI (30-84%). Insomnia and circadian rhythm disorders are the most frequent disorders among the population that has suffered mild TBI, while hypersomnolence disorders are more frequent in populations that have suffered moderate and severe TBI. The syndrome of obstructive sleep apnea and restless leg syndrome are also very frequent in these patients; and patients exposed to multiple TBIs (war veterans) are especially susceptible to sleep disorders. The treatment of these disorders requires taking into account the particularities of these patients. In conclusion, diagnosis and treatment of sleep disorders should become part of routine clinical practice and cease to be anecdotal (as it is today) in patients with TBI. In addition, it is necessary to continue carrying out research that reveals the best therapeutic approach to these patients.

Bypassing TBI: Metabolic Surgery and the Link between Obesity and Traumatic Brain Injury-a Review

Obesity is a common outcome of traumatic brain injury (TBI) that exacerbates principal TBI symptom domains identified as common areas of post-TBI long-term dysfunction. Obesity is also associated with increased risk of later-life dementia and Alzheimer's disease. Patients with obesity and chronic TBI may be more vulnerable to long-term mental abnormalities. This review explores the question of whether weight loss induced by bariatric surgery could delay or perhaps even reverse the progression of mental deterioration. Bariatric surgery, with its induction of weight loss, remission of type 2 diabetes, and other expressions of the metabolic syndrome, improves metabolic efficiency, leads to reversal of brain lesions seen on imaging studies, and improves function. These observations suggest that metabolic/bariatric surgery may be a most effective therapy for TBI.

DNA Methylation Patterns of Chronic Explosive Breaching in U.S. Military Warfighters

Background: Injuries from exposure to explosions rose dramatically during the Iraq and Afghanistan wars, which motivated investigation of blast-related neurotrauma. We have undertaken human studies involving military "breachers" -exposed to controlled, low-level blast during a 3-days explosive breaching course. Methods: We screened epigenetic profiles in peripheral blood samples from 59 subjects (in two separate U.S. Military training sessions) using Infinium MethylationEPIC BeadChips. Participants had varying numbers of exposures to blast over their military careers (empirically defined as high ≥ 40, and conversely, low < 39 breaching exposures). Daily self-reported physiological symptoms were recorded. Tinnitus, memory problems, headaches, and sleep disturbances are most frequently reported. Results: We identified 14 significantly differentially methylated regions (DMRs) within genes associated with cumulative blast exposure in participants with high relative to low cumulative blast exposure. Notably, NTSR1 and SPON1 were significantly differentially methylated in high relative to low blast exposed groups, suggesting that sleep dysregulation may be altered in response to chronic cumulative blast exposure. In comparing lifetime blast exposure at baseline (prior to exposure in current training), and top associated symptoms, we identified significant DMRs associated with tinnitus, sleep difficulties, and headache. Notably, we identified KCNN3, SOD3, MUC4, GALR1, and WDR45B, which are implicated in auditory function, as differentially methylated associated with self-reported tinnitus. These findings suggest neurobiological mechanisms behind auditory injuries in our military warfighters and are particularly relevant given tinnitus is not only a primary disability among veterans, but has also been demonstrated in active duty medical records for populations exposed to blast in training. Additionally, we found that differentially methylated regions associated with the genes CCDC68 and COMT track with sleep difficulties, and those within FMOD and TNXB track with pain and headache. Conclusion: Sleep disturbances, as well as tinnitus and chronic pain, are widely reported in U.S. military service members and veterans. As we have previously demonstrated, DNA methylation encapsulates lifetime exposure to blast. The current data support previous findings and recapitulate transcriptional regulatory alterations in genes involved in sleep, auditory function, and pain. These data uncovered novel epigenetic and transcriptional regulatory mechanism underlying the etiological basis of these symptoms.

Geographically based risk assessment of sleep disorders and disease states impacting medical readiness across active duty army installations from military medical databases in fiscal year 2017

BACKGROUND

The impact of sleep disorders on active duty Soldiers' medical readiness is clinically significant. Sleep disorders often present high comorbidity with disease states impacting readiness ranging from obesity and drug dependence. Patient data generated from military health databases can be accessed to examine such relationships. The current study performed a risk assessment of sleep disorders, obesity, tobacco use, and substance abuse based on geographical distribution of active duty Army installations through a comprehensive analysis of the Office of the Army Surgeon General Health of the Force report, specifically for Fiscal Year 2017, which summarizes data collected during 2016.

METHODS

Health incidences (percent active duty per installation) were queried from the Health of the Force Fiscal Year 2017 (n = 471,000; 85.5% male, >70% between 18 and 34). Nonparametric ranked tests identified active duty Army installations at low risk (green; <25% percentile relative to mean rank), moderate risk (amber; 25%-50% percentile relative to mean rank), and high risk (red; >75% percentile relative to mean rank). Pearson's correlations determined extent of generalized comorbidity of sleep disorders with obesity, tobacco use, and substance abuse across all installations.

RESULTS

Large combat arms and training installations of the Southern U.S. were at highest risk for sleep disorder. Mean rank comparisons for sleep disorders versus obesity (P = .306), tobacco use (P = .378), and substance abuse (P = .591) did not differ for each installation. There was a high degree of generalized comorbidity of diagnosed sleep disorder with obesity (P < .001; r² = 0.963), tobacco use (P < .001; r² = 0.928), and substance abuse (P < .001; r² = 0.968).

CONCLUSIONS

These risk assessments mirror geographical risk data from civilian populations which is surprising because there is a large degree of inter-individual variability in geographical origin, race/ethnicity, and socioeconomic statuses within a single Army installation. Nevertheless, these data demonstrate strong geographical influences on medical readiness in active duty Soldiers comparable to civilian sectors.

Behavioral Deficits in Animal Models of Blast Traumatic Brain Injury

Blast exposure has been identified to be the most common cause for traumatic brain injury (TBI) in soldiers. Over the years, rodent models to mimic blast exposures and the behavioral outcomes observed in veterans have been developed extensively. However, blast tube design and varying experimental parameters lead to inconsistencies in the behavioral outcomes reported across research laboratories. This review aims to curate the behavioral outcomes reported in rodent models of blast TBI using shockwave tubes or open field detonations between the years 2008–2019 and highlight the important experimental parameters that affect behavioral outcome. Further, we discuss the role of various design parameters of the blast tube that can affect the nature of blast exposure experienced by the rodents. Finally, we assess the most common behavioral tests done to measure cognitive, motor, anxiety, auditory, and fear conditioning deficits in blast TBI (bTBI) and discuss the advantages and disadvantages of these tests.

Do Criminals Live Faster Than Soldiers and Firefighters? : A Comparison of Biodemographic and Psychosocial Dimensions of Life History Theory

A high risk of morbidity-mortality caused by a harsh and unpredictable environment is considered to be associated with a fast life history (LH) strategy, commonly linked with criminal behavior. However, offenders are not the only group with a high exposure to extrinsic morbidity-mortality. In the present study, we investigated the LH strategies employed by two groups of Polish men: incarcerated offenders (N = 84) as well as soldiers and firefighters (N = 117), whose professions involve an elevated risk of injury and premature death. The subjects were asked to complete the Mini-K (used as a psychosocial LH indicator) and a questionnaire which included a number of biodemographic LH variables. Although biodemographic and psychosocial LH indicators should be closely linked with each other, the actual connection between them is unclear. Thus, this study was driven by two aims: comparing LH strategies in two groups of men with a high risk of premature morbidity-mortality and investigating the relationship between the biodemographic and psychosocial LH dimensions. The study showed that incarcerated men employed faster LH strategies than soldiers and firefighters, but only in relation to biodemographic variables (e.g., number of siblings, age of sexual initiation, life expectancy). No intergroup differences emerged regarding psychosocial LH indicators. Moreover, the correlation analysis showed a weak association between biodemographic and psychosocial LH indicators. The results strengthen the legitimacy of incorporating biodemographic LH traits into research models and indicate the need for further research on the accuracy of the Mini-K. The possible explanations for the intergroup differences in LH strategies are discussed.

Sleep difficulties as a predictor of attrition in United States Air Force recruits

STUDY OBJECTIVES

The objective of the study was to estimate the rates of "difficulty sleeping at night" in newly enlisted United States Air Force (USAF) recruits and determine if these sleep difficulties predicted 1-year attrition (discharge for any reason) independently and after controlling for all other Lackland Behavioral Questionnaire (LBQ) predictors.

METHODS

The LBQ was administered to 202,339 active duty, enlisted USAF trainees completing basic military training at Joint Base San Antonio-Lackland, Texas, from January 2006 to December 2012. Attrition data were obtained through the Defense Manpower Data Center.

RESULTS

Fifty percent of the sample reported at least occasional sleep difficulties in the past year, with 9% reporting frequent (6% = often and 3% = most of the time) sleep difficulties. Twelve percent of trainees had been discharged within one year, and sleep difficulties were the second strongest significant predictor of this attrition after accounting for all other predictor variables in the LBQ, Wald χ² = 254.19, p < .0001. Trainees with frequent sleep difficulties were 2.7 times more likely to be discharged than those without sleep difficulties based on the odds ratio statistic.

CONCLUSIONS

Rates of self-reported frequent "difficulty sleeping…," before basic training started, were similar to civilian populations and were the second strongest predictor of one-year attrition. "Difficulty sleeping…" encompasses many sleep problems (e.g., insomnia, sleep deprivation, circadian misalignment). Future studies should determine what specific sleep difficulties pose the greatest risk for attrition and then determine if they can be remediated, thus decreasing attrition risk, or if they should be a focus of screening.

Burn pit exposure in military personnel: is there an effect on sleep-disordered breathing?

PURPOSE

Exposure to elevated concentrations of respirable particulate matter (< 10 μm) may influence sleep-disordered breathing. Burn pits as utilized by the US military in the Middle East until 2011 produced elevated particle matter concentrations. We seek to determine if subjective exposure to burn pits during deployment affects prevalence or severity of obstructive sleep apnea (OSA) in military personnel.

METHODS

As part of a prospective observational study of previously deployed military personnel with exertional dyspnea (n = 145), all patients underwent pulmonary function testing, screening for burn pit exposure, and if warranted by questionnaires, overnight polysomnography. A total of 100 patients completed all testing. For analysis, patients were classified into a burn pit exposure group (45 patients) and a no exposure group (55 patients). Additional analyses were performed on those endorsing burn pit maintenance during deployment (25 patients) and those with > 12 h of daily exposure (17 patients).

RESULTS

The prevalence of OSA, defined by apnea-hypopnea index (AHI) > 5/h, was similarly high in both groups (69% vs. 71%, p = 0.83). Surprisingly, the mean AHI was lower in the exposed group (12.8/h vs. 19.7/h, p = 0.04) while nadir of oxygen saturation was similar (87% vs. 86%, p = 0.39). Subgroup analyses revealed similar findings in those who performed burn pit maintenance (prevalence = 80%, p = 0.58; AHI = 14.8, p = 0.16) and those with > 12 h of daily exposure (prevalence = 88%, p = 0.33; AHI = 18.0, p = 0.62).

CONCLUSIONS

Subjective burn pit exposure does not appear to influence OSA development in previously deployed military personnel. Given the high rate of OSA in this cohort, continued investigation of deployment exposures which may influence sleep-disordered breathing is recommended.

The Management of Chronic Insomnia Disorder and Obstructive Sleep Apnea: Synopsis of the 2019 U.S. Department of Veterans Affairs and U.S. Department of Defense Clinical Practice Guidelines

DESCRIPTION

In September 2019, the U.S. Department of Veterans Affairs (VA) and the U.S. Department of Defense (DoD) approved a new joint clinical practice guideline for assessing and managing patients with chronic insomnia disorder and obstructive sleep apnea (OSA). This guideline is intended to give health care teams a framework by which to screen, evaluate, treat, and manage the individual needs and preferences of VA and DoD patients with either of these conditions.

METHODS

In October 2017, the VA/DoD Evidence-Based Practice Work Group initiated a joint VA/DoD guideline development effort that included clinical stakeholders and conformed to the Institute of Medicine's tenets for trustworthy clinical practice guidelines. The guideline panel developed key questions, systematically searched and evaluated the literature, created three 1-page algorithms, and advanced 41 recommendations using the GRADE (Grading of Recommendations Assessment, Development and Evaluation) system.

RECOMMENDATIONS

This synopsis summarizes the key recommendations of the guideline in 3 areas: diagnosis and assessment of OSA and chronic insomnia disorder, treatment and management of OSA, and treatment and management of chronic insomnia disorder. Three clinical practice algorithms are also included.

Traumatic brain injury and sleep disturbances in combat-exposed service members and veterans: Where to go next?

OBJECTIVE

To synthesize the current evidence on sleep disturbances in military service members (SMs) and veterans with traumatic brain injury (TBI).

METHODS

An electronic literature search first identified abstracts published from 2008-2018 inclusively referencing sleep, TBI, and military personnel from Operation Enduring Freedom, Operation Iraqi Freedom, Operation New Dawn, and Persian Gulf veterans. Selection criteria eliminated studies on non-combat TBI, open or penetrating injuries, and articles where the relationship between sleep and TBI was not directly examined. Articles on all military branches and components, those currently serving and veterans-ranging from medical chart reviews to clinical trials, were included. Forty-one articles were selected for full text-review.

RESULTS

Twenty-four papers estimated the prevalence of sleep disturbances in TBI. Eight studies demonstrated the contribution of common co-occurring conditions, most notably posttraumatic stress disorder, to the relationship between disrupted sleep and TBI. Ten studies differentiated sleep profiles between military SMs and veterans with and without acute TBI and detected significant differences in sleep disturbances across the course of injury. Longitudinal studies were scarce but helped to establish the temporal relationship between sleep disturbances and TBI and isolate sleep-related mechanisms influencing TBI prognosis. Only three studies reported on interventions for improving sleep quality and TBI symptoms. Systematic research testing assessments and interventions that target sleep disturbances for improving sleep, TBI symptoms, and long-term functional outcomes were identified as critical knowledge gaps.

CONCLUSION

Findings unequivocally establish that sleep disturbances are highly prevalent in SMs and veterans with TBI. However, studies testing the effectiveness of treatments for improving sleep in military groups with TBI have been limited and their results inconsistent. This review highlights a critical opportunity for advancing military medicine through future research aimed at identifying and testing sleep-focused treatments in SMs and veterans with combat-related TBI.

Sleep in the United States Military

The military lifestyle often includes continuous operations whether in training or deployed environments. These stressful environments present unique challenges for service members attempting to achieve consolidated, restorative sleep. The significant mental and physical derangements caused by degraded metabolic, cardiovascular, skeletomuscular, and cognitive health often result from insufficient sleep and/or circadian misalignment. Insufficient sleep and resulting fatigue compromises personal safety, mission success, and even national security. In the long-term, chronic insufficient sleep and circadian rhythm disorders have been associated with other sleep disorders (e.g., insomnia, obstructive sleep apnea, and parasomnias). Other physiologic and psychologic diagnoses such as post-traumatic stress disorder, cardiovascular disease, and dementia have also been associated with chronic, insufficient sleep. Increased co-morbidity and mortality are compounded by traumatic brain injury resulting from blunt trauma, blast exposure, and highly physically demanding tasks under load. We present the current state of science in human and animal models specific to service members during- and post-military career. We focus on mission requirements of night shift work, sustained operations, and rapid re-entrainment to time zones. We then propose targeted pharmacological and non-pharmacological countermeasures to optimize performance that are mission- and symptom-specific. We recognize a critical gap in research involving service members, but provide tailored interventions for military health care providers based on the large body of research in health care and public service workers.

Insomnia prevalence among U.S. Army soldiers with history of TBI

PURPOSE/OBJECTIVE

To determine the rate of insomnia among active-duty soldiers with and without a history of traumatic brain injury (TBI). Research Method and Design: Data were extracted from the All Army Study (AAS), a cross-sectional, self-report survey completed by a representative sample of 21,499 U.S. Army soldiers from 2011 to 2013 as part of the Army Study to Assess Risk and Resilience in Servicemembers. History and severity of TBI were determined by participants' responses to questions regarding postinjury symptomology (i.e., loss of consciousness [LOC], amnesia, etc.). Insomnia symptoms were defined using DSM-5 criteria as measured by the Brief Insomnia Questionnaire.

RESULTS

Approximately 63% of respondents reported lifetime history of mild TBI (mTBI), with ∼7% endorsing a history of moderate to severe TBI. Insomnia symptom prevalence rate increased with brain injury severity and number of TBIs with LOC, with ∼51% of those with mTBI and ∼55% of those with moderate to severe TBI demonstrating clinically elevated insomnia symptoms, compared to ∼37% insomnia prevalence rate among servicemembers without TBI.

CONCLUSION/IMPLICATIONS

Results suggest high (> 50%) prevalence rates of insomnia symptoms among servicemembers with a lifetime history of brain injury, underscoring the need for behavioral sleep medicine interventions among active-duty personnel. (PsycINFO Database Record (c) 2019 APA, all rights reserved).