BACKGROUND: The aim of this study was to investigate the effectiveness of the mental rotation test (MRT) based on virtual reality (VR) in predicting pilots’ spatial visualization ability (SVA).METHODS: Based on VR, 118 healthy pilots’ SVA were evaluated by MRT. The pilot flight ability evaluation scale was used as the criterion of test validity. According to the scale score, pilots were divided into high, middle, or low spatial ability groups pursuant to the 27% allocation principle. Differences in reaction time (RT), correct rate (CR), and correct number per second (CNPS) of MRT between groups were compared. Correlations between scale scores and MRT scores were analyzed. RT, CR, and CNPS of MRT among different age groups and between genders were also compared.RESULTS: The RT of the high spatial ability group was remarkably slower than that of the low spatial ability group (363.4 ± 140.2 s, 458.1 ± 151.7 s). The CNPS of the high spatial ability group was dramatically higher than that of the low spatial ability group (0.111 ± 0.045 s, 0.086 ± 0.001 s). There were no significant differences in RT, CR, and CNPS between different genders. Pilots in the 29–35 yr old age group had considerably slower RT than those in the 22–28 yr old age group (330.8 ± 140.3 s, 417.2 ± 132.7 s). Pilots in the 29–35 yr old age group had conspicuously higher CNPS than pilots in the 22–28 yr old age group (0.119 ± 0.040 s, 0.096 ± 0.036 s). All pilots’ scale scores were positively correlated with CNPS (r = 0.254) and negatively correlated with RT (r = -0.234).DISCUSSION: MRT based on VR has a good discrimination efficacy for SVA of pilots and is a good indicator for the SVA component measurement.Zhang M, Wang M, Feng H, Liu X, Zhai L, Xu X, Jin Z. Pilots’ spatial visualization ability assessment based on virtual reality. Aerosp Med Hum Perform. 2023; 94(6):422–428.

BACKGROUND: Fighter pilots’ Team Situation Awareness (TSA) has been studied from the perspective of TSA accuracy, which represents how closely the pilots’ collective knowledge is aligned with the real world. When TSA accuracy is low, the pilots can have similarly or dissimilarly inaccurate SA. The concept of TSA similarity represents the similarity of team members’ collective knowledge. This paper investigates how TSA accuracy and similarity of F/A-18 pilots are associated with performance.METHOD: Data were extracted from simulated air combat missions. Performance and TSA were investigated in 58 engagements. The accuracy and similarity of pilots’ SA were elicited and performance was evaluated. TSA accuracy and similarity were analyzed with respect to the flights’ performance, and the independent variables were events in which the flights initiated engagements with enemy aircraft versus events in which the flights were engaged by enemy aircraft.RESULTS: With the mentioned events as the main effect, there were statistically significant differences at all levels of TSA accuracy and similarity. With performance as the main effect, there were also significant differences at all levels of TSA accuracy and similarity. TSA accuracy and similarity were superior in offensive engagements and when engagements were successful.DISCUSSION: The main contribution of this paper is the extension of the concept of TSA similarity to air combat: both TSA similarity and accuracy were higher when the flight was engaging the enemy aircraft, compared to situations when the flight itself was being engaged. The results also suggest that low TSA accuracy and similarity have a statistically significantly negative impact on the flights’ performance.Mansikka H, Harris D, Virtanen K. Accuracy and similarity of team situation awareness in simulated air combat. Aerosp Med Hum Perform. 2023; 94(6):429–436.

INTRODUCTION: Recently, an analysis of Canadian seaplane accidents terminating in water (1995–2019) was conducted, but ultralight water accidents were excluded due to differences from general aviation operations. This is the first literature that reports a series of ultralight accidents that occurred in water. The purpose of this paper is to identify the circumstances surrounding ultralight water accidents in Canada and to identify actions with the potential to improve survival.METHODS: Ultralight water accidents that were reported to the Transportation Safety Board of Canada between 1990 and 2020 were reviewed.RESULTS: Of the 1021 accidents that involved ultralights, 114 terminated in water, involving 155 occupants and 8 fatalities, yielding an occupant mortality rate of 5%. Of the accidents, 52% occurred during landing. There was less than 15 s warning in 78% of cases, which included five (63%) fatalities. The aircraft inverted in 40% of the accidents and, in 21%, it sank immediately. Loss of control was the terminal cause of the accident in 43% of cases, while adverse environmental conditions were reported in 38% of accidents. Little or no details were included on lifejacket or restraint harness use, status of emergency exits, water temperature, or occupant diving experience or underwater escape training.CONCLUSIONS: The mortality rate in ultralight aircraft water accidents was less than half that of helicopter and seaplane ditchings, but the lack of warning time was similar. All pilots and passengers need to have a well-practiced survival schema before strapping in and can benefit from underwater escape training.MacDonald C, Brooks C, McGowan R, Rosberg A. Canadian ultralight accidents in water (1990 to 2020). Aerosp Med Hum Perform. 2023; 94(6):437–443.

INTRODUCTION: Despite all our dreams and enthusiasm, the essential question of whether our species can ever live permanently in space remains unanswered. The 1975 NASA Ames Design Study on Space Settlements demonstrated how human physiology constrains and determines human habitat design in space. Our scientific understanding about the risks of and standards for microgravity (and rotation rate if centrifugally generated), ionizing radiation, and atmosphere pressure and composition, remains inadequate a half century later. In addition, there are newly recognized physiological challenges to living safely in space, including spaceflight-associated neuro-ocular syndrome (SANS), extravascular hemolytic anemia, and other factors that affect every human cell and organ system. A comprehensive review was conducted to establish what we have learned and what is still required to know about the pathophysiology of long-term space travel and living in space since my first report in 1978. The results determine not only how, but if we can realistically plan to inhabit the cosmos that surrounds us.Winkler LH. Human physiological limitations to long-term spaceflight and living in space. Aerosp Med Hum Perform. 2023; 94(6):444–456.

BACKGROUND: How to determine team composition is one of many key topics when developing humanity’s next deep space exploration programs. Behavioral health and performance among spaceflight teams are key aspects impacted by team composition and cohesiveness.METHODS: This narrative review highlights areas of consideration for building cohesive teams in long duration spaceflight environments. The authors gathered information from a variety of team-behavior related studies that focused on team composition, cohesion, and dynamics, as well as others topics such as faultlines and subgroups, diversity, personality traits, personal values, and crew compatibility training.RESULTS: The literature suggests that team cohesion occurs more easily when individuals are similar to one another, and deep-level variables such as personality and personal values have a greater impact on crew compatibility than surface level variables such as age, nationality, or gender. Diversity can have both positive and negative impacts on team cohesiveness.CONCLUSION: Team composition, as well as pre-mission conflict resolution training can greatly impact group cohesion. This review aims to map areas of concern and assist with crew planning for long duration spaceflight missions.Gangeme A, Simpson B, De La Torre GG, Larose TL, Diaz-Artiles A. A comprehensive look behind team composition for long duration spaceflight. Aerosp Med Hum Perform. 2023; 94(6):457–465.

BACKGROUND: Internal jugular vein (IJV) congestion occurs during spaceflight. Historically, IJV distension on the International Space Station (ISS) has been quantified using single slice cross-sectional images from conventional 2D ultrasound with remote guidance. Importantly, the IJV is an irregular shape and highly compressible. Consequently, conventional imaging is susceptible to poor reproducibility due to inconsistent positioning, insonation angle, and hold-down pressure, especially when controlled by novice sonographers (i.e., astronauts). Recently, a motorized 3D ultrasound was launched to the ISS that mitigates angulation errors and has a larger design, allowing for more consistent hold-down pressure and positioning. This short communication compares IJV congestion measured with 2D vs. 3D methods during spaceflight.METHODS: IJV was measured prior to and following a 4-h venoconstrictive thigh cuff countermeasure. Data were acquired from three astronauts approximately halfway through their 6-mo missions.RESULTS: The 2D and 3D ultrasound results were not congruent in all astronauts. 3D ultrasound confirmed that the countermeasure reduced IJV volume in three astronauts by approximately 35%, whereas 2D data were more equivocal. These results indicate that 3D ultrasound provides less error-prone quantitative data.DISCUSSION: These data are the first to compare 2D and 3D methods during spaceflight in the same participants by using a known countermeasure that reduces IJV congestion. The current results demonstrate that 3D ultrasound should be the preferred imaging method when trying to measure venous congestion in the IJV, and that 2D ultrasound results should be interpreted with caution.Patterson C, Greaves DK, Robertson A, Hughson R, Arbeille PL. Motorized 3D ultrasound and jugular vein dimension measurement on the International Space Station. Aerosp Med Hum Perform. 2023; 94(6):466–469.

INTRODUCTION: With increasing engagement of commercial spaceflight participants in spaceflight activities, the evaluation of individuals with medical conditions not previously characterized in the spaceflight environment is of particular interest. Factors such as acceleration forces experienced during launch, reentry, and landing of spacecraft could pose an altered risk profile in some individuals due to known disease. Bleeding diatheses present a unique concern in the spaceflight environment given hypergravity exposure and, particularly, the potential for injury resulting from transient or impact acceleration.CASE REPORT: A 26-yr-old Caucasian man with severe hemophilia A and no detectable endogenous Factor VIII (FVIII) volunteered for participation in hypergravity exposures simulating spaceflight. His treatment regimen included 50 IU · kg⁻¹ FVIII-Fc fusion protein intravenous administration every 96 h, with supplemental FVIII administration as needed for injury or bleeding. The subject experienced two profiles at the National Aerospace Training and Research Center (NASTAR), with maximum exposure +4.0 G_z, +4.5 G_x, 6.1 G resultant, and maximum onset rate <0.5 G_z · s⁻¹ and +1 G_x · s⁻¹. The subject reported no abnormal events during the profiles other than brief mild vertigo. No petechial hemorrhage, ecchymosis, or other bleeding was noted during or after profiles. Supplemental FVIII was not required before, during, or after exposure.DISCUSSION: Inherited bleeding disorders present several potential concerns that must be evaluated prior to spaceflight participation. Cautious review and management of medical history, adherence and barriers to treatment, duration of spaceflight and longitudinal management concerns, and a thorough and detailed risk/benefit assessment may provide a future pathway for inclusion of individuals with hematological disorders in commercial spaceflight.Reeves IA, Blue RS, Auñon-Chancellor S, Harrison MF, Shah R, Powers WE. Tolerance of centrifuge-simulated commercial spaceflight in a subject with hemophilia A. Aerosp Med Hum Perform. 2023; 94(6):470–474.

BACKGROUND: Heart rate (HR) indicates the number of beats per minute (bpm) of the heart, while heart rate variability (HRV) indicates the temporal fluctuation of the intervals between adjacent beats (NN). HRV expresses neuro-cardiac activity and is generated by heart-brain interactions and dynamics related to the function of the autonomic nervous system (ANS) and other components (e.g., body and ambient temperature, respiration, hormones, blood pressure). We are carrying out a series of experimental investigations with the aim of studying HRV in student pilots during training.CASE REPORT: For this purpose, we used a Holter electrocardiograph equipped with three channels and five electrodes positioned on the chest of the subject who participated in our investigation. The case report refers to a student pilot who, during a flight mission with the instructor, had to face a forced landing and a flap failure. We report data based on analysis of the time domain and frequency domain related to operations on the ground before the flight, during the flight, and on the ground after the flight.DISCUSSION: Our initial conclusion is that the extent of HRV constitutes an “energy store” for better cardiac performance in eustress activities. During advanced tasks, the “Total Power” of the heart decreases because the RR intervals are forced toward low values, where the heart is less able to be modulated by its many controllers. Furthermore, this experimental protocol can be useful to flight instructors for the training process of student pilots.Li Volsi G, Monte IP, Aruta A, Gulizzi A, Libra A, Mirulla S, Panebianco G, Patti G, Quattrocchi F, Bellantone V, Castorina W, Arcifa S, Papale F. Heart rate variability of a student pilot during flight training. Aerosp Med Hum Perform. 2023; 94(6):475–479.

INTRODUCTION: Fighter pilots must withstand high G_z-forces that can damage the cervical spine. Strength of the cervical musculature is of vital importance when it comes to preventing these G-induced neck injuries. However, there is very little evidence on valid neck muscle strength measurement methods for fighter pilots. The aim of this study was to examine the validity of a commercial force gauge attached to a pilot’s helmet for measuring isometric neck muscle strength.METHODS: A total of 10 subjects performed maximal isometric cervical flexion, extension, and lateral flexion with the helmet-attached gauge and with a weight stack machine, which was used as a reference. Electromyography (EMG) activities were recorded from the right and left sternocleidomastoids and cervical erector spinae muscles during all measurements. Paired t-tests, Pearson correlation coefficient, and Wilcoxon’s test were used to analyze the data.RESULTS: Difference of mean force values between the devices was statistically significant in all directions. Pearson correlation coefficient varied between 0.73 and 0.89 and it was highest in cervical flexion. EMG activities were significantly different only in the left CES during flexion.DISCUSSION: The helmet-attached gauge is a valid tool for measuring isometric neck muscle strength and is best used as a means to compare individual differences in strength levels or to track the progress of strength development.Nyländen P, Virmavirta M, Sovelius R, Kyröläinen H, Honkanen T. A flight helmet-attached force gauge for measuring isometric neck muscle strength. Aerosp Med Hum Perform. 2023; 94(6):480–484.

INTRODUCTION: An episode of prolonged exposure to high altitude can cause hypoxia and have significant health consequences. In people with a high-altitude disorder, the body reacts by producing a protein called hypoxia-inducible factor (HIF), which triggers a series of physiological changes and serves a central role in the hypoxia response. Its activity is regulated by the oxygen-dependent degradation of the HIF-1α protein (HIF-1A gene). Therefore, the effects of low oxygen tension in high altitude were explored using fluorescent sensors of hypoxia.METHODS: The development of the sensor provided more sensitivity for detecting hypoxia by generating a calibration of optimized parameters such as reagent concentrations, reagent volumes, and device dimensions.RESULTS: There is a high sensitivity and specificity in detecting the changes of HIF-1α protein hypoxia using the feasibility hypoxia test. This would enable point-of-care (POC) testing and individual self-administration, resulting in faster and more accurate results that can be used for a robust diagnostic approach and enhanced health surveillance, particularly in high-altitude exposure.Shaharuddin S, Rahman NMANA, Masarudin MJ, Alamassi MN, Saad FFA. HIF-1 sensor in detecting hypoxia tolerance at high altitude. Aerosp Med Hum Perform. 2023; 94(6):485–487.