UAE RESEARCHERS STUDY MENTAL STRESS OF ASTRONAUTS DURING PROLONGED SPACE MISSIONS

Dr. Hasan al Nashash

Professor of Electrical and Biomedical Engineering

Unvirsity

A study carried out by the American University of Sharjah in UAE looked into mental stress in prolonged space missions utilizing technologies such as machine learning. Its findings will offer solutions to astronauts to decrease stress levels as well as help in choosing astronauts.

The 240 days of Isolation

Dr. Hasan Al Nashash, Professor at the Electrical Engineering Department of the American University of Sharjah assessed together with his colleagues in the Neuroengineering Research Group mental stress during 240 days of isolation in a confined environment. This group is composed of Dr. Hasan Al-Nashash, Dr. Fares Al-Shargie and Dr. Usman Tariq.

The study proposed utilizing electroencephalography (EEG), alpha amylase and behavioral measures to assess the level of mental stress during a period of 240 days of isolation and confinement. The study quantified the levels of mental stress using the reaction time (RT) to stimuli, accuracy of target detection, and the functional connectivity network of the brain’s electrical beta EEG signals estimated by phase locking values (PLV).

The researchers hypothesized that 240 days of isolation and confinement would result in various elevated levels of mental stress and EEG and machine-learning models can be used to classify different levels of mental stress. Time-limited voice contact with a simulated control center was the only connection with the outside world.

The study is important for several reasons. According to Dr. Al Nashash, “Isolation and confinement can put the human body under a large amount of psycho-neuroendocrine strain, which results in measurable pathophysiologic symptoms. There have been studies of human space missions which demonstrated that space exploration involves various health risks. The effects of the space environment on human health mainly studied in terms of microgravity, cosmic radiation, and closed confined environments. Researchers have reported that microgravity can cause balance disorders, decreased bone mineralization, and muscle-disuse atrophy. In addition, psychological stress in closed, confined, multi-cultural environments in space can be a serious health issue. “

He believes that the reason for stress is because astronauts are isolated from earth, while living and working in a confined environment with low levels of mental and physical stimulation. These pose real dangers in space, and in particular, limitation in coping resources to those stressors.

Biomarkers identified

As such, the Neuroengineering Research Group aimed to develop and identify biomarkers for the assessment of stress, so that astronauts can easily check their stress level when they are unable to receive regular professional face-to-face support. Detecting the influence of psychological stress at its early stages is particularly important in prolonged space missions to avoid negative consequences.

Previous studies that have looked into the effects of the space environment on human health have mainly studied microgravity, cosmic radiation, and closed confined environments. Several research groups have reported that confined environments can cause physical problems including fatigue, balance disorders, decreased bone mineralization and muscular atrophy.

Collaboration with UAE Space Centre

Dr. Al Nashash explained, “The study was carried out in collaboration with Mohammed Bin Rashid Space Centre (MBRSC). It involved five astronauts, including UAE astronauts Saleh Alameri and Abdullah Alhammadi, who were put into a confined environment for 240 days from November 2021 to July 2022 in the SIRIUS facility, during which they experienced simulated long-distance space travel. The Facility was artificially lit; temperature was maintained at 2223- °C. The astronauts had some personal contact with each other and a time-limited voice contact with the control center. Daily activities included eight hours of work, eight hours of free time and eight hours of sleep. They were required to conduct around 70 different experiments including ours.”

Results

The results of the study showed that the alpha amylase level increased by 62% from the beginning of the mission to the end of the 240-days mission. This indicates that isolation and confinement contribute to elevation of mental stress. The functional connectivity network showed a significant decrease in the information flow in the frontal regions across all subjects with statistical significance of p<0.05 (P > 0.05 is the probability that the null hypothesis is true. 1 minus the P value is the probability that the alternative hypothesis is true. A statistically significant test result (P ≤ 0.05) means that the test hypothesis is false or should be rejected. A P value greater than 0.05 means that no effect was observed.) Meanwhile, the behavioral data showed no differences from the beginning to the end of the 240-days mission, which could be due to the short data recording time of 10 minutes during each experiment time.

The overall results suggested that the frontal beta EEG connectivity can be used as a potential biomarker for detecting elevated stress in an isolated and confined environment. According to the study it is very important to develop biomarkers to detect stress in its early stages before it becomes chronic. Identifying behavioral, psychological, and biological markers of the characteristics that predispose prospective long-duration space exploration is required for exploration missions. The accurate prediction will guide crew selection tactics, spacecraft habitability specifications, and the necessary behavioral health safeguards for interplanetary missions.

The study was carried out in collaboration with Mohammed Bin Rashid Space Centre (MBRSC). It involved five astronauts, including UAE astronauts Saleh Alameri and Abdullah Alhammadi, who were put into a confined environment for 240 days from November 2021 to July 2022 in the SIRIUS facility, during which they experienced simulated long-distance space travel.

Utilizing machine learning and EEG

The researchers utilized multiple machine learning models to detect elevated stress levels during the 240-day confinement. The machine learning classifiers differentiated between four levels of stress with classification accuracy of 91.8%, 91.4%,

90.2%, 87.8, and 81% using linear discriminant analysis (LDA), Support Vector Machine (SVM), k-nearest neighbor (KNN), Naïve bayes (NB) and decision trees (DT).

EEG was recently used in two space studies to examine how isolation affected the brain›s physiology and emotional state. One study (MARS105) found that three months of isolation produced a general decrease of brain activity as well as a decrease in perceived physical state and motivation.

Al-Shargie adds, “There is ample evidence which demonstrates that stress hormones are strongly linked to cognitive performance including memory. However, in this research, the effect of stress on cognition was not investigated. In addition, the astronauts had some personal contact with each other and time-limited voice contact with the control center. So, the focus of this research was not on isolation from other humans. We were interested in detecting the influence of psychological stress in prolonged space missions.”

Future Impact on space missions

As per Dr. Al Nashash, the findings of this research will impact future space missions locally in the UAE and internationally. The findings will help develop techniques to mitigate stress at its early stages to protect astronauts’ mental health.

Another important result of the study is that the findings can be used to develop criteria for selecting astronauts. Dr. Al Nashash states, “Our results show that mental stress was common amongst all participating astronauts during the 240day confinement. However, there were some variations due to individual differences. In fact, this is one of the prime reasons why advanced neuroimaging and AI should be used in the selection of potential astronauts.”

Finally, the findings can also be used and applied to our modern-day life whether this is in workplace environments, especially for jobs that include long office hours, or firefighters, security personnel, military, students, and researchers.