Elevation of Acute Mental Stress by Doubt and Work Interruption in High-risk Professional Environment

Abstract

Aims: The INTRA group is a robotic emergency response organization for nuclear accidents. The staff must therefore be prepared for this type of situation of high stress level. To ensure that, the applicants to join the group are tested at the time of recruitment. In 2021, the recruitment tests were reinforced by completing the stress resistance test. At the time, this test consisted only of a Stroop test without any other measure of stress, providing only access to performance under stress. It was therefore necessary to improve this stress test. Methodology: The new stress-test (version 1) was broken down into several consecutive sequences including a Stroop test, a psychotechnical test under acute stress conditions, and again a Stroop test. The applicant was equipped with a chest strap with sensors to access to the heart rate variability (HRV) for each sequence and a performance score was calculated. The cross-comparison of the results allowed access to the subject's performance under acute stress as well as to the resilience to stress by comparing the subject's performance between the two Stroop tests. Between 2021 and 2024, 26 subjects were subjected to the stress test: average age 46.5 years old (SD=8.6), 15% female. Results: The study of the stress-test was carried out in 2 periods, using respectively version 1 and 2 of the psychotechnical test. The analysis of the protocol based on version 1 made it possible to hypothesize that interruption and doubt or outcome uncertainty contributed to increasing the level of stress during the Stroop test, but were absent of the psychotechnical test. It was therefore decided to systematically generate interruption and doubt during the psychotechnical test in period 2. The results were very satisfactory: the percentage of subjects with a higher level of stress on the psychotechnical test compared to the Stroop test increased from 33 to 73% (p=.05) and the average increase in HRV was up to 41% for the psychotechnical test compared to the Stroop test (p<.02) while not significant in period 1. Conclusion: Doubt or outcome uncertainty related to decision-making combined with activity interruption is a significant factor in the generation of acute mental stress. In the context of the present study, doubt leads to questioning and comparing different options whereas uncertainty relates to the validity of the outcome resulting from decision-making.