Evidence for -Gz Adaptation Observed with Wearable Biosensors During High Performance Jet Flight.

INTRODUCTION: Few studies have evaluated physiological responses to high acceleration forces during actual flight and to our knowledge no normative data has been acquired by technologies such as wearable biosensors during high performance jet aircraft operations. METHODS: In-flight physiological data from an FDA cleared portable triaxial accelerometer and bio-sensor were observed from five active duty F-18 pilots of the Naval Flight Demonstration Squadron (Blue Angels). Of the five pilots, three were formation pilots who flew lower G profiles and two were solo pilots who flew higher G profiles. Physiological parameters monitored were heart rate, respiratory rate, temperature, caloric expenditure, and duration of exposure to levels of acceleration. RESULTS: Evaluated were 25 practice demonstration flights; 9 flights were excluded secondary to incomplete or inaccurate physiological data. We observed no significant bradycardia during a total of 189 maneuvers which met inclusion criteria for push-pull events (PPE) or isolated -Gz exposures. Further analysis of 73 PPE revealed an overall significant rise in HR following the PPE, where mean heart rate was 106 (95% CI, 100:112) at the beginning of the push and 129 (95% CI, 123:135) following the pull. DISCUSSION: A majority of the flights monitored provided reliable physiological data. Initial data suggests, contrary to currently held aeromedical doctrine, maneuvers such as the "push-pull" do not evoke vasovagal based bradycardic responses in aerobatic pilots. Possible explanations for these findings are sympathetic nervous system activation through adaptation and/or sustained isometric resistance from control inputs, both of which are areas of future research for our team.Rice GM, Snider D, Moore JL, Lavan JT, Folga R, VanBrunt TB. Evidence for -Gz adaptation observed with wearable biosensors during high performance jet flight. Aerosp Med Hum Perform. 2016; 87(12):996-1003.

Positive Adjustment Among American Repatriated Prisoners of the Vietnam War: Modeling the Long-Term Effects of Captivity.

A longitudinal lifespan model of factors contributing to later-life positive adjustment was tested on 567 American repatriated prisoners from the Vietnam War. This model encompassed demographics at time of capture and attributes assessed after return to the U.S. (reports of torture and mental distress) and approximately 3 decades later (later-life stressors, perceived social support, positive appraisal of military experiences, and positive adjustment). Age and education at time of capture and physical torture were associated with repatriation mental distress, which directly predicted poorer adjustment 30 years later. Physical torture also had a salutary effect, enhancing later-life positive appraisals of military experiences. Later-life events were directly and indirectly (through concerns about retirement) associated with positive adjustment. Results suggest that the personal resources of older age and more education and early-life adverse experiences can have cascading effects over the lifespan to impact well-being in both positive and negative ways.

Optimism predicts positive health in repatriated prisoners of war.

"Positive health," defined as a state beyond the mere absence of disease, was used as a model to examine factors for enhancing health despite extreme trauma. The study examined the United States' longest detained American prisoners of war, those held in Vietnam in the 1960s through early 1970s. Positive health was measured using a physical and a psychological composite score for each individual, based on 9 physical and 9 psychological variables. Physical and psychological health was correlated with optimism obtained postrepatriation (circa 1973). Linear regressions were employed to determine which variables contributed most to health ratings. Optimism was the strongest predictor of physical health (ß = -.33, t = -2.73, p = .008), followed by fewer sleep complaints (ß = -.29, t = -2.52, p = .01). This model accounted for 25% of the variance. Optimism was also the strongest predictor of psychological health (ß = -.41, t = -2.87, p = .006), followed by Minnesota Multiphasic Personality Inventory-Psychopathic Deviate (MMPI-PD; McKinley & Hathaway, 1944) scores (ß = -.23, t = -1.88, p = .07). This model strongly suggests that optimism is a significant predictor of positive physical and psychological health, and optimism also provides long-term protective benefits. These findings and the utility of this model suggest a promising area for future research and intervention.

Sleep and resilience: a longitudinal 37-year follow-up study of Vietnam repatriated prisoners of war.

This study examined sleep histories associated with resilience after trauma defined as a continuous lack of psychiatric illness across 37 years. Data were drawn from a 37-year follow-up examination of the effects of the Vietnam prisoner of war (POW) experience. The Robert E. Mitchell Center for POW Studies is a unique institution holding the only longitudinal study of the effects of the American POW experience in existence. The study used a sample of 440 Vietnam repatriated prisoners of war (RPWs). Psychiatric disorders were assessed at repatriation (1973) and were continued annually by a psychiatrist or clinical psychologist. Sleep issues before, during, and after captivity were assessed upon repatriation during medical examinations. Odds ratios examining presence of sleep symptoms show resilient RPWs reporting fewer symptoms compared to nonresilient RPWS before, during, and after captivity. Logistic regression comparing before, during, and after indicates fewer reported sleep disturbance symptoms after captivity was the strongest predictor of resilience (b = -0.82, Wald chi2 (1) = 16.70, p < 0.000). Reporting fewer sleep complaints, but not necessarily an absence of them before, during, and after the trauma predicts resilience across time.

Return to combat duty after concussive blast injury.

Little data exist regarding the acute assessment of blast concussion and the course of recovery in the combat zone, as most research has examined service members long after they have returned home. This manuscript examined a case series of 377 service members seen for acute concussion evaluation following medical evacuation from the battlefield in Helmand Province, Afghanistan. Of these, 111 were assessed for concussion prior to their return to the continental USA for other severe physical injuries. Of the remainder, and when comparing those who returned to duty (RTD)/recovered from concussion in the combat zone and those who did not, data indicate that those who did not RTD were older and were more likely to endorse symptoms of combat stress. Quicker recovery times were associated with less severe headaches and fewer acute symptoms at the time of injury as well as the absence of combat stress reaction. Variables that were not associated with RTD and/or recovery were Military Acute Concussion Evaluation (MACE) cognitive scores and whether or not individuals suffered loss of consciousness. While MACE scores were not associated with recovery, they were deemed clinically useful as a part of a serial concussion evaluation if the initial MACE was given within 6 h of the blast. Implications for battlefield concussion assessment and management as well as future research directions are discussed.

Optimism predicts resilience in repatriated prisoners of war: a 37-year longitudinal study.

Resilience, exhibiting intact psychological functioning despite exposure to trauma, is one perspective as to why some people who are exposed to trauma do not develop symptoms. This study examines the prisoner of war experience to expand our understanding of this phenomenon in extreme cases of trauma such as prolonged captivity, malnourishment, and physical and psychological torture. The study examined the United States' longest detained American prisoners of war, those held in Vietnam in the 1960s through early 1970s. A logistic regression analysis using resilience, defined as never receiving any psychiatric diagnosis over a 37-year follow-up period, as the outcome was performed (n = 224 with complete data). Six variables showing at least small effects emerged: officer/enlisted status, age at time of capture, length of solitary confinement, low antisocial/psychopathic personality traits, low posttraumatic stress symptoms following repatriation, and optimism. Odds ratios (ORs) and confidence intervals (CIs) confirmed the significance and relative strength of these variables, with a range from OR = 0.54, 95% CI [0.13, 2.29] to OR = 1.11, 95% CI [1.04, 1.17]. When all variables were examined continuously and categorically, dispositional optimism was the strongest variable, accounting for 17%, continuously, and 14%, categorically. We discuss optimism as a protective factor for confronting trauma and the possibility of training to increase it.

Long-term effects of coping with extreme stress: longitudinal study of Vietnam-era repatriated prisoners of war.

Captivity stressors and coping strategies were assessed shortly after the repatriation of Vietnam-era prisoners of war, and physical and mental health were assessed almost three decades later. Given research on coping goodness-of-fit, specifically the extent to which coping effects depend on situational controllability, we proposed that endorsement of the usefulness of avoidance-based strategies in captivity would be predictive of better later-life health. Findings indicated that approach-based and avoidance-based coping both moderated the link between physical torture and later physical health functional status, whereas approach-based coping moderated the link between injuries at capture and later mental health. Specifically, greater endorsement of avoidance-based coping was associated with better long-term physical health for prisoners who experienced the most physical torture. Lower endorsement of approach-based coping was associated with better long-term mental health for prisoners who reported the most injuries at the time of capture.

Posttraumatic stress disorder and metabolic syndrome: retrospective study of repatriated prisoners of war.

OBJECTIVE: We conducted a retrospective study of metabolic data for Vietnam-era repatriated prisoners of war (RPWs) and a comparison group to determine if metabolic syndrome (MbS) was more common in those individuals with clinically diagnosed, current or lifetime posttraumatic stress disorder (PTSD) as suggested in a recent report. METHODS: The metabolic data of our patients nearest the time of psychiatric evaluation (1998-2004) for PTSD were analyzed using both an analysis of variance and logistic regression. RESULTS: Although we found elevated triglyceride levels (40 mg/dl higher) in RPWs with PTSD who met MbS criteria, overall the prevalence of MbS was the same in RPWs with and without PTSD and comparison group. Moreover, current PTSD symptom severity did not increase the likelihood of MbS. CONCLUSIONS: Our results from these repatriates who actively participate in a 37-year medical follow up program do not support the conclusion that MbS occurs more commonly in individuals with current PTSD.

Potential association of posttraumatic stress disorder and decreased bone mineral density in repatriated prisoners of war.

OBJECTIVE: We conducted a retrospective evaluation of bone mineral density data collected during routine medical follow-up evaluations of 241 Vietnam-era male repatriated prisoners of war, with and without the lifetime diagnosis of posttraumatic stress disorder (PTSD), and 79 subjects in a comparison group. METHODS: Dual-energy X-ray absorptiometry scans evaluated total hip and lumbar spine T-scores. A multivariate analysis of covariance was performed on the data using age, body mass index, ethnicity, and reported alcohol consumption as covariates. RESULTS: There was a significant effect of group on total hip, but not lumbar spine, T-scores. Pairwise comparisons revealed statistically lower total hip T-scores in repatriates with a lifetime history of PTSD in comparison to both the comparison group and repatriates without a lifetime history of PTSD. CONCLUSION: In this study of elderly repatriated prisoners of war, we noted an association between a lifelong history of PTSD and decreased bone mineral density at the hip.

Menstrual suppression for combat operations: advantages of oral contraceptive pills.

BACKGROUND: increasing numbers of women are deployed to austere settings in which menstruation may impose logistical challenges. Minimal data exists about the use of oral contraceptive pills (OCPs) for menstrual suppression in this population. Post-deployment survey was undertaken to establish prevalence of continuous OCP use, perceived barriers, and associations with menstrual burden in a military population within the austere environment. METHODS: voluntary and anonymous 44-item questionnaire. RESULTS: of 500 women, 78% (n = 390) had personal experience using OCPs and 66% (n = 330) desired menstrual suppression. However, only 40% (n = 192) reported any OCP use and only 21% (n = 99) reported continuous use during deployment. Sixty-seven percent of women reported some difficulty in daily pill compliance and nearly half (45%) missed ≥ 1 pill per week in the austere setting. Continuous users were nearly twice as compliant as conventional users (p = .019) and compliant OCP users reported significantly less menstrual burden than noncompliant users (p = .017). Almost all women (85%) desired mandatory education about menstrual suppression through OCPs. CONCLUSION: despite OCP experience and desire for amenorrhea, prevalence of extended cycle OCP use in this population is low. Extended OCPs users in the austere setting report improved compliance and reduced menstrual burden compared with conventional users. Education about OCPs is highly desirable for most military women and may benefit those in austere settings.

Personality traits in clinically referred aviators: two clusters related to occupational suitability.

BACKGROUND: The Five Factor Model (FFM) of normal personality provides a compelling framework for investigating personality subtypes in large military populations. The FFM was used to determine whether a sample of clinically referred military aviators exhibited commonly occurring personality clusters. METHODS: The Revised NEO Personality Inventory (NEO-PI-R) was used to evaluate 956 clinically referred U.S. Naval aviators and flight officers on the domains of neuroticism (N), extroversion (E), openness (O), agreeableness (A), and conscientiousness (C). The scores were subjected to model-based cluster analysis and emergent clusters were compared with respect to their scores and clinical outcomes. RESULTS: A two-cluster model provided the best fit to the data. MANOVA indicated significant differences between the two cluster groups with respect to four of the five factors (N, E, A, and C). The greatest differences were for N and E, with the smaller group (Group 1, N = 291) being significantly more neurotic and less extroverted than Group 2 (N = 665). Cluster membership had more specificity (0.74) than sensitivity (0.59) for predicting adverse clinical outcome, with the probability of an adverse clinical outcome increasing from 0.14 to 0.28 for those in the neurotic and introverted Group 1. CONCLUSIONS: Elevated neuroticism and depressed extraversion were the defining traits of the personality cluster less suited for aviation duty (Group 1). Results support assessment of neuroticism and extroversion during clinical mental health evaluations related to military aviation duty.

Menstrual suppression using oral contraceptives: survey of deployed female aviation personnel.

INTRODUCTION: Increasing numbers of women perform aviation duties in the combat flight environment. Oral contraceptive pills (OCPs) afford numerous health and operational benefits, including prevention of anemia and suddenly incapacitating conditions, as well as menstrual suppression when taken continuously. Until now, the use of OCPs in the combat flight environment has not been examined. METHODS: An anonymous, voluntary questionnaire was distributed to 62 female U.S. Army aviation personnel who had recently deployed in support of combat flight operations to characterize continuous OCP use and perceived barriers to this practice, as well as to determine associations with menstrual burden. RESULTS: There were 81% (N=50) of the women who had personal experiences using OCPs and 93% (N=58) were aware that continuous use can suppress menstruation. For deployment, 66% (N=41) desired menstrual suppression, yet only 33% (N=20) reported any OCP use. Even fewer (15%; N=10) reported using continuously. Of the women who did not use OCPs continuously, 35% had insufficient knowledge about OCPs and 44% of women reported difficulty in remembering to take a daily pill. Continuous OCP users were more compliant (P = 0.019), reported less spotting (P = 0.007) and fewer unexpected menstrual cycles (P = 0.03) than conventional OCP users. A trend toward reduced cramping was noted (P = 0.064). Most women (60%) desired standardized entry-level education about menstrual suppression through OCPs. CONCLUSIONS: The use of continuous OCPs is low in deployed women with aviation-related duties, yet a majority desires menstrual suppression. Continuous OCP use in this setting is associated with significantly improved compliance and significant reductions in specific menstrual burdens. Entry-level education is desirable and may reduce barriers to continuous OCP use by addressing risks, side effects, and daily pill adherence strategies. Flight surgeons should provide further education and consider continuous OCP dosing in the austere environment of combat flight.

A study of the psychological factors in outcomes for officers who survive ballistic assault.

Among law enforcement personnel, who are subject to assault with firearms, there has been a trend toward decreased mortality and physical morbidity associated with the use of personal protective armor (PPA). Although there has been an increase in the rate of survival, studies of the unique psychological factors associated with this type of assault are essentially nonexistent. The prevalence and nature of the negative psychological sequelae associated with this type of assault and psychological injury, along with effective prevention techniques, were studied through retrospective interviews of registrants in two "body armor survival clubs." Significant relationships were found between available interventions and behavioral health outcomes. In addition to reducing the likelihood of poor health outcomes, departmentally based interventions were related to officers' ability to develop positive interpretations of the event and engage in fewer high risk behaviors. These findings suggest that departmental interventions, such as debriefings, are meaningful and may help improve outcomes for officers fired upon, but not wounded, in the line of duty.

A retrospective comparison of anesthetic agents in electroconvulsive therapy.

A recent lack of availability of the anesthetic agent methohexital in the United States allowed for a naturalistic study of the efficacy and the adverse effects of alternatives. Methohexital, propofol, and thiopental were compared as anesthetic agents for electroconvulsive therapy in 95 patients treated during a 23-month period in a general public hospital. Missed seizures and arrhythmias were infrequently observed (<4% for any agent). Methohexital was found significantly related to longer seizure durations in comparison with both other agents (P < 0.01). The use of propofol was associated with increased risk of missed seizure (8.9%) compared with methohexital (3.9%) and thiopental (3.2%). Propofol was also associated with higher doses of administered energy, with a statistically significant difference (P = 0.018) observed between propofol and thiopental. Although propofol required the greatest energy delivery, it was associated with the shortest seizure durations. Methohexital resulted in the longest seizure duration, and thiopental was associated with the least amount of energy delivery with an intermediate seizure length.

Type II decompression sickness in naval hypobaric chambers: A case of mistaken identity?

INTRODUCTION: Historically, U.S. Navy clinicians have used the U.S. Navy Dive Manual for guidance in the diagnosis and treatment of injuries incurred during hyper- or hypobaric operations. Based on this manual, paresthesias are considered to be central nervous system manifestations and thus are classified as Type II (severe) decompression sickness (DCS). Yet given the highly successful response to treatment of peripheral nervous system manifestations of DCS in the literature, both the diving and aviation communities have questioned its classification as "severe" DCS. This record review was undertaken to examine U.S. Naval severe cases of altitude DCS with the goal of identifying dissimilarities between hypobaric facilities in classification and incidence. METHODS: Hypobaric exposures and cases were reviewed from quarterly training reports maintained at the Naval Operational Medicine Institute, Pensacola, FL, between January 1993 and April 2004. Cases were analyzed for age, gender, flight profile, symptom complex, type of DCS, and treatment provided. RESULTS: There were 50,355 hypobaric exposures resulting in 97 cases of altitude DCS. Of the 97 cases of diagnosed DCS, 58 were classified as Type II, while 39 were Type I. Of the 58 cases of Type II DCS, 29 were diagnosed as Type II by the sole finding of non-dermatomal paresthesias. DISCUSSION: Type II DCS, a designation traditionally reserved for severe DCS, is frequently diagnosed by the sole finding of non-dermatomal paresthesias in Naval hypobaric training. A review and revision of the U.S. Naval Aviation classification system for altitude DCS should be undertaken with emphasis on severity not symptomatology.

Perceived cognitive function and emotional distress following coronary artery bypass surgery.

Many patients experience decrements in cognitive function and emotional adjustment following coronary artery bypass graft (CABG) surgery. Moreover, cognitive decline and emotional distress are often positively related. This study evaluated the cross-sectional and prospective associations of emotional and subjective cognitive complaints, to assess the hypothesis that they would be mutually reinforcing. Participants were 76 CABG patients recruited from Akron General Medical Center. Depression and anxiety symptoms and perceived cognitive difficulties were evaluated at a baseline postsurgical visit and re-assessed 5 months later. Emotional symptoms and perceived cognitive difficulties were significantly related both within and across time. After controlling for numerous potential confounds, baseline perceived cognitive difficulties predicted a more negative course of emotional symptoms during follow-up. Baseline emotional symptoms did not predict the course of perceived cognitive difficulties. Perceptions of cognitive decline may contribute to emotional distress in patients post-CABG.

Validity of the Clock Drawing Test in predicting reports of driving problems in the elderly.

BACKGROUND: This study examined the use of the Folstein Mini Mental Status Exam (MMSE) and the Clock Drawing Test (CDT) in predicting retrospective reports of driving problems among the elderly. The utility of existing scoring systems for the CDT was also examined. METHODS: Archival chart records of 325 patients of a geriatric outpatient clinic were reviewed, of which 162 had CDT results (including original clock drawings). T-test, correlation, and regression procedures were used to analyze the data. RESULTS: Both CDT and MMSE scores were significantly worse among non-drivers than individuals who were currently or recently driving. Among current or recent drivers, scores on both instruments correlated significantly with the total number of reported accidents or near misses, although the magnitude of the respective correlations was small. Only MMSE scores, however, significantly predicted whether or not any accidents or near misses were reported at all. Neither MMSE nor CDT scores predicted unique variance in the regressions. CONCLUSIONS: The overall results suggest that both the MMSE and CDT have limited utility as potential indicators of driving problems in the elderly. The demonstrated predictive power for these instruments appears to be redundant, such that both appear to assess general cognitive function versus more specific abilities. Furthermore, the lack of robust prediction suggests that neither are sufficient to serve as stand-alone instruments on which to solely base decisions of driving capacity. Rather, individuals who evidence impairment should be provided a more thorough and comprehensive assessment than can be obtained through screening tools.

Incidence of decompression sickness in hypoxia training with and without 30-min O2 prebreathe.

BACKGROUND: All naval aviators, navigators, and aircrewmen are required to participate in hypoxia familiarization training. This training is performed in a hypobaric chamber and is considered high risk due to the potential for barotrauma and/or decompression sickness (DCS). Prior analysis of the DCS in U.S. Navy hypobaric chambers revealed a significantly higher incidence among inside observers (IOs) compared with students. In response to these reports, all IOs are required to denitrogenate by breathing 100% oxygen for 30 min prior to altitude exposure (prebreathing). Although the Army, Navy, and Air Force prebreathe for 30 min prior to most hypobaric training exposures, there have been no reports validating the efficacy of this measure. This study examined the incidence of altitude DCS during training exposures to simulated altitudes of 25,000 ft (25k) and 35,000 ft (35k) in IOs and students, some of whom prebreathed and some of whom did not. METHODS: Exposures and DCS cases for a period of 9 yr were tabulated from training reports maintained at the Naval Operational Medicine Institute in Pensacola, FL. Chi-square or Fisher's Exact test was used to compare the data sets and p < or = 0.05 was considered significant. RESULTS: The overall DCS incidence for students and IOs for all chamber profiles was 0.25%. The incidence for 25k was 0.29% for students who did not prebreathe and 0.15% for IOs who did (p = 0.10). Within the student group there was a 0.44% DCS incidence for 25k with no prebreathe and a 0.17% DCS incidence for 35k with prebreathe (p = 0.004). CONCLUSIONS: A 30-min prebreathe prior to altitude exposure appears to contribute to a reduction in the risk of DCS during hypobaric chamber training.

Assessment of personality and crew interaction skills in successful naval aviators.

PURPOSE: We were interested in studying a full range of successful aviators to discern which personality factors were present and whether these factors correlate with age, rank, and accumulated flight time. METHOD: The Armstrong Laboratory Aviator Personality Survey (ALAPS) was administered to 312 designated naval aviators and flight officers from a variety of aircraft communities. The sample included O-3/O-4 elite aviators who were selected for their squadron billets based on superior performance, O-5/O-6 aviators selected for command positions, and 59 flag officers. RESULTS: The junior aviators scored higher on the factor associated with Dogmatism and lower on the factor associated with Team Orientation and Socialness. This pattern was reversed for the flag officers, while O-5/O-6 aviators received intermediate scores on each of these factors. CONCLUSIONS: The present study demonstrates a correlation between specific ALAPS factors and experience, rank, age, and flight time. The combination of high Dogmatism, low Team Orientation, and low Socialness in junior aviators could suggest lower openness to crew input and increased risk for mishaps.