INTRODUCTION: Managing cognitive demand is critical for aviation safety. Yet, accurately assessing pilot workload during complex flight maneuvers remains challenging. This study evaluated an integrated methodology combining real-time cognitive engagement indicators to provide a comprehensive assessment and assess the reliability of physiological and subjective measures for monitoring operator state.

METHODS: Six experienced U.S. Army rotary-wing pilots completed simulated high-workload flight scenarios like low-altitude, reconnaissance, and air threat avoidance maneuvers. Continuous wireless electroencephalography (EEG), heart rate data, and subjective workload ratings were recorded during the flights.

RESULTS: EEG engagement indices and heart rate variability metrics demonstrated reliable within-subject consistency across trials for individual pilots, with mean intraclass correlation coefficient values ranging from 0.59–0.69. Both measures exhibited synchronized fluctuations across pilots at key events, increasing during high workload segments and decreasing in lower demand periods. Subjective ratings also showed good within-subject reliability, with mean intraclass correlation coefficient values ranging from 0.74–0.85. These findings underscore the reliability of our measurements, instilling confidence in the validity of our research.

DISCUSSION: The findings of this study provide strong support for the feasibility of using a multi-measure approach that integrates EEG, heart rate variability, and subjective ratings. This approach can continuously monitor real-time cognitive workload fluctuations during simulated rotary-wing operations. While objective measures showed within-subject consistency, substantial between-subject variability highlights the importance of individualized neurocognitive profiling. The integration of neurophysiological, autonomic, subjective, and environmental data holds great promise for the future of pilot workload assessment despite the challenges posed by individual differences.

D’Alessandro M, Mackie R, Berger T, Ott C, Sullivan C, Curry I. Real-time neurophysiological and subjective indices of cognitive engagement in high-speed flight. Aerosp Med Hum Perform. 2024; 95(12):885–896.

INTRODUCTION: During centrifuge-simulated suborbital spaceplane flights, launch and re-entry frequently cause visual symptoms, and G-induced loss of consciousness can occur. G-related effects may be more prominent during re-entry from microgravity on actual flights. A modified anti-G maneuver that does not involve a breath strain and is suitable for members of the public may be effective against these effects.

METHODS: Recruited were 13 healthy subjects (age range 34–82 yr) who had experienced visual symptoms during centrifuge-simulated suborbital centrifuge profiles as part of a previous study. Onset and duration of greyout were recorded during an acceleration profile simulating spaceplane launch and re-entry in an upright seated position. The profile was undertaken twice: once in a relaxed state and once while undertaking anticipatory muscle tensing consisting of pre-tensing the leg and abdominal muscles (i.e., the muscle tensing component of a standard aircrew anti-G straining maneuver).

RESULTS: Muscle tensing was well tolerated and prevented 100% of greyout on launch and 54% of greyout on re-entry, as well as delaying the onset of greyout when it did occur on re-entry. Combined with the previous study’s data, this indicates an overall population incidence of greyout of ∼70% on launch, falling to zero with muscle tensing, and ∼80% on re-entry, falling to ∼37% with muscle tensing.

DISCUSSION: Anticipatory pre-tensing of leg and abdominal muscles prevented greyout completely during the launch phase and partially during re-entry, and should be considered as part of routine suborbital spaceplane operations. Studies providing relevant data from actual flights are required.

Pollock RD, Britton JK, Green NDC, Hendriksen D, Hodkinson PD, Anderton RA, Smith TG. Prevention of G-induced effects on vision and consciousness during simulated suborbital spaceflight. Aerosp Med Hum Perform. 2024; 95(12):897–901.

INTRODUCTION: Left bundle branch block (LBBB) is disqualifying for aircrew in the U.S. Air Force (USAF), although outcomes for these patients is limited. We used data from the USAF School of Aerospace Medicine to study this population.

METHODS: A retrospective review was performed on aircrew with LBBB identified using the Central Electrocardiographic Library database. Analysis included baseline participant demographics, cardiac risk factors, and any available cardiovascular results. Critical endpoints were coronary artery disease (CAD), cardiomyopathy (CM) (left ventricular ejection fraction of <50%) and/or clinical heart failure, and death from any cause.

RESULTS: At diagnosis: 271 patients met eligibility; mean age of 40.24 ± 7.39 yr. Of the 147 (54%) patients who had coronary angiography, 7 (2.6%) had aggregate stenosis 50–119% and 5 (1.8%) had aggregate stenosis ≥120%. Two patients underwent percutaneous coronary intervention, with an additional 13 (4.8%) patients demonstrating left ventricular ejection fraction of <50%; 12 were nonischemic. Longitudinal data was available for 177 (65%) patients; median follow-up was 10 yr (range 0–58 yr). During this period, 2 patients developed CAD with aggregate stenosis ≥120% and 5 had myocardial infarction. There were 37 (20%) patients who developed CM. Among 41 deaths, mean age was 75.1 ± 14.1 yr. Nine were premature (<60 yr).

DISCUSSION: Asymptomatic aviators with LBBB had elevated risk for CM (20%). Association with CAD exceeded 10% at 10 yr. Findings support current USAF policy requiring extensive cardiac evaluation and follow-up for LBBB. More prospective research is needed to validate these findings.

McGregor P-C, Palileo EV, Haynes JT, Davenport ED. Aeromedical concerns in asymptomatic aviators with left bundle branch block. Aerosp Med Hum Perform. 2024; 95(12):902–907.

INTRODUCTION: Military pilots are subjected to unique pulmonary demands, particularly in high performance jets. The hypobaric environment necessitates use of on-board oxygen, breathing masks, and regulators to increase oxygen pressure, affecting ventilation and breathing responses. Safety features like pilot flight equipment and strapping into an ejection seat further impact pilot pulmonary function. Acceptable pulmonary function required for high performance aircraft is not well understood. There is no consensus among North Atlantic Treaty Organization (NATO) partners on how to perform pulmonary screening and which conditions and medications are acceptable.

METHODS: This study was conducted with a questionnaire, gathering retrospective data. In 2019, questionnaires were sent out to national aeromedical representatives from 29 NATO countries and 3 allied nations. Questions were current aeromedical regulations used, pulmonary data collected from each individual pilot, acceptable pulmonary conditions, and acceptable medical treatments. Data were collected before the COVID-19 pandemic; a follow-up questionnaire was sent out after to ask if screening policies had changed.

RESULTS: A total of 16 questionnaires were returned from 13 NATO and 3 allied nations. This equates to an overall response rate of 50%. Pulmonary function testing is conducted on pilot applicants in 15/16 countries and 9/16 perform pulmonary function testing at every follow-up aeromedical examination as well. Conventional chest X-rays as a part of the first initial aeromedical examination are being used in 8/16 countries.

DISCUSSION: This study describes the divergent medical standards for pulmonary function in NATO aircrew and confirms that no standards for best practice exist.

Frijters E, Lindgaard K, Regn D, Gray G, Naylor J, Bushby A, Guettler N, Leino T. Policies on pulmonary screening and management of respiratory conditions in military pilots. Aerosp Med Hum Perform. 2024; 95(12):908–912.

INTRODUCTION: Facial expression perception is the process by which someone can interpret the emotion of another individual using their facial cues. Below-average scores on tests designed to measure facial expression recognition (FER) accuracies are associated with inappropriate behavioral responses and are often linked to mental or neurological disorders. Head-down bed rest microgravity analog studies show changes in facial emotion processing that may indicate a behavioral health risk during spaceflight.

METHODS: During short-duration space analog missions at two separate facilities, 15 subjects took daily FER tests before, during, and after the mission. Each test was accompanied by questionnaires measuring either potential causal or impacted variables: stress, depression, loneliness, irritability, risk-taking, empathy, and intrinsic motivation.

RESULTS: Analysis of variance and post hoc t-tests showed that during the mission, the subjects were less likely to identify angry, sad, or fearful faces as disgusted compared to the baseline. Also, interest/enjoyment and perceived competence increased throughout the mission lifecycle. Multiple regression analyses were able to account for greater than 20% of the variance for depression and health/safety risk-taking using the FER data.

DISCUSSION: Changes in FER during space mission simulations show that perception changes are not limited to microgravity analogs. A perceptual change was observed during the short-duration missions, but there is not sufficient evidence to show behavioral health impacts. However, associations between FER and the questionnaires show a potential to develop predictive models, countermeasures, or psychological monitoring tools using FER. Additional research is required to determine the efficacy of such tools during long-duration spaceflight.

Van Hoy S. Facial expression perception and psychological changes during space analogs. Aerosp Med Hum Perform. 2024; 95(12):913–918.

INTRODUCTION: A suite of human health and performance metrics can be used to provide a holistic cognitive, physical, and emotional view of an individual and assess how well they are integrated with the overall system during spaceflight missions. The combination of such individual metrics as defined here is notionally termed “crewmember operational state.”

METHODS: This work identifies and defines the contributing components that comprise the proposed crewmember operational state.

RESULTS: Considerations of how to measure the components in a spaceflight environment are summarized and the steps required to analyze and integrate these measurements into an operational framework are outlined. Use of the measurements and integration steps are then extended into several applications relevant to human spaceflight mission design and operations.

DISCUSSION: For the framework and applications defined here to become operationally feasible, several limitations and gaps that remain to be addressed are presented with recommended future research and enabling technology advancement needs.

Zero M, Klaus D, Arquilla K, Fanchiang C. Defining and measuring crewmember operational state for spaceflight operations. Aerosp Med Hum Perform. 2024; 95(12):919–929.

INTRODUCTION: This review aims to assess the safety and efficacy of the use of ultraviolet-C technology for disinfecting aircraft and compare it with other methods currently used in the aviation industry.

METHODS: The authors conducted a comprehensive, systematic review of the literature on disinfection of aircraft. Independent double reviews were conducted and consultations with a third reviewer were performed in the event of disagreements.

DISCUSSION: Although infectious disease transmission in aircraft cabins has been shown to be low, a recent study has described reports of passengers on commercial aircraft infecting other passengers. Incorporating ultraviolet-C technology into aircraft disinfection protocols holds the potential to add a significant level of risk mitigation to effectively reduce disease transmission and enhance safety.

DeJohn C, Belland K, Garcia D. Methods of aircraft disinfection to reduce airborne infectious disease transmission. Aerosp Med Hum Perform. 2024; 95(12):930–936.

BACKGROUND: Swimming-induced pulmonary edema (SIPE), also called immersion pulmonary edema, is a form of exertional pulmonary edema associated with swimming and/or water immersion without aspiration. Most case reports on SIPE feature young, healthy patients who were scuba-diving, surface swimming, snorkeling, or breath-hold diving before experiencing symptoms of dyspnea, chest pain/tightness, cough, and hemoptysis. The incidence of SIPE is thought to be between 0.4–5%. Although symptoms typically resolve with oxygenation and ventilation, SIPE can be fatal, making recognition of SIPE crucial, especially for operational medical providers overseeing water training events and exercises.

CASE REPORT: A 28-yr-old healthy man began experiencing severe shortness of breath during early morning pool training. Oxygen saturation was in the low 80s and the patient was put on 15-L supplemental oxygen via nonrebreathing mask. Rales were present bilaterally on lung auscultation. He denied aspiration of water. Due to his persistent hypoxia, the patient was transported to an emergency department. He received a two-view chest X-ray, showing only bibasilar pulmonary opacities. He maintained 100% saturation once oxygen was removed and was able to be discharged to continue in the selection course.

DISCUSSION: Although SIPE may affect a small percentage of swimmers, military training in extreme conditions such as cold, lack of sleep, and profound exertion increases the risk for SIPE. Additionally, a patient who develops SIPE in the water is at risk for drowning. As SIPE may be fatal, military providers, especially those working with Special Operations, must be aware of how to diagnose and treat SIPE.

O’Keefe CL, Clemente Fuentes RW, Salinas E. Swimming-induced pulmonary edema in a member participating in a special tactics selection course. Aerosp Med Hum Perform. 2024; 95(12):937–939.

INTRODUCTION: The current regulatory approach to U.S. airline pilot mental health may have unintended negative consequences including healthcare avoidance and screening imprecision. An alternative approach should aim to address these factors while maintaining safety. The authors summarize the following related to mental health in U.S. airline pilots: 1) current regulatory approach and limitations, 2) available regulatory tools within the Sparrow fundamentals, and 3) a proposed novel regulatory approach. The authors propose the simultaneous utilization of multiple models to minimize the negative consequences of healthcare avoidance and screening imprecision. The proposed framework aims to address current limitations.

Hoffman WR, Suh A, Sprott T, Manderson K, Snyder Q, Sparrow M, Tvaryanas A. A proposed framework to regulate mental health in airline pilots. Aerosp Med Hum Perform. 2024; 95(12):940–943.