Evaluation of a Fatigue Detector Using Eye Closure-Associated Indicators Acquired from Truck Drivers in a Simulator Study.

This paper presents a camera-based prototype sensor for detecting fatigue and drowsiness in drivers, which are common causes of road accidents. The evaluation of the detector operation involved eight professional truck drivers, who drove the truck simulator twice-i.e., when they were rested and drowsy. The Fatigue Symptoms Scales (FSS) questionnaire was used to assess subjectively perceived levels of fatigue, whereas the percentage of eye closure time (PERCLOS), eye closure duration (ECD), and frequency of eye closure (FEC) were selected as eye closure-associated fatigue indicators, determined from the images of drivers' faces captured by the sensor. Three alternative models for subjective fatigue were used to analyse the relationship between the raw score of the FSS questionnaire, and the eye closure-associated indicators were estimated. The results revealed that, in relation to the subjective assessment of fatigue, PERCLOS is a significant predictor of the changes observed in individual subjects during the performance of tasks, while ECD reflects the individual differences in subjective fatigue occurred both between drivers and in individual drivers between the 'rested' and 'drowsy' experimental conditions well. No relationship between the FEC index and the FSS state scale was found.

[Aggravating factors in teachers' work and fatigue]. / Czynniki obciazajace w pracy nauczycieli a zmeczenie.

BACKGROUND: Teachers are a occupational group in which, due to the type and specificity of work, it can be expected that the feeling of fatigue will be very intense. However, there has been little research into this problem. The aim of the research was to assess the level of fatigue after work and chronic fatigue in teachers, and to determine whether and to what extent it depends on occupational and non-occupational loads. MATERIAL AND METHODS: The stratified sampling model was used to select the sample, where the layers were the type of school and its location (size of a town/city). All teachers from selected schools were invited to participate. Overall, 650 questionnaires were distributed and 403 teachers returned completed questionnaires. Fatigue after work was assessed on the basis of answers to the following question: "Do you feel tired after work?" and chronic fatigue using the Fatigue Assessment Scale. A special questionnaire was developed to assess other factors that might affect the level of fatigue. The Subjective Stress Assessment at Work Questionnaire, Cohen's Perceived Stress Scale, a part of the Questionnaire of Professional Loads of the Teacher and a list of additional factors disturbing the work were used. RESULTS: The study involved 70 men aged 35-63 years and 333 women (24-64 years). The groups did not differ significantly in terms of mean age. The level of fatigue, regardless of gender, was mostly influenced by time pressure, rush, mismanagement of the pace of work to individual abilities, increasing workload, an excess of responsible tasks, a lack of support from superiors, a low prestige of the profession, a lack of pedagogical successes, a sense of the lack of meaning in work, and the negative impact of work on family life, as well as non-occupational loads and insufficient rest. CONCLUSIONS: The conducted study allowed for determining the profile and frequency of occupational and non-occupational factors affecting the level of fatigue in teachers. Med Pr. 2021;72(3):283-303.

[Using of the ROSA method to assess the musculoskeletal load on computer workstations]. / Zastosowanie metody ROSA do oceny obciazenia ukladu miesniowo-szkieletowego na komputerowych stanowiskach pracy.

BACKGROUND: The aim of the study was to compare the musculoskeletal system load assessed using the rapid office strain assessment (ROSA) and rapid upper limb assessment (RULA) methods in computer operators, and to determine the correlation of the obtained results with the occurrence and intensity of musculoskeletal complaints (MSCs) in these individuals. MATERIAL AND METHODS: In a group of 72 persons (38 women and 34 men) working with a computer for > 4 h/day, the ROSA and RULA methods were used to assess the load, while a questionnaire modeled on the Standardized Nordic Questionnary was used to assess the frequency and severity of MSCs. RESULTS: Musculoskeletal complaints occurred in about 66% of the investigated women and 62% of the investigated men within the previous year. The results of the ROSA and RULA methods were not convergent. The final result of the ROSA method (scale 1-10 pts) was 2-6 pts (M = 3.51±1.09), while the final result of the RULA method (scale 1-7 pts) ranged 2-4 pts (3.00±0.17). The values of partial and final scores in the ROSA method were correlated with the number of concurrent ailments and intensity of complaints in various regions of the musculoskeletal system. The assessment of the position of particular parts of the body during work, performed using the RULA method, in people with or without MSCs was almost identical. CONCLUSIONS: The use of the ROSA method has shown that it is a useful and easy-to-use tool for assessing computer workstations and can be successfully disseminated. Med Pr. 2019;70(6):675-99.

Can alveolar hypoventilation due to kyphoscoliosis be a contraindication to driving?

Road accidents are among the main fatalities worldwide and drowsy driving is a significant cause of road deaths where drivers are at fault. There are well known diseases which impair sensory and cognitive functions and can cause sleepiness during driving. Such diseases can be an important contraindication to driving because they may have an adverse effect on its safety. Thus, medical examinations for drivers should also be directed at identifying any possible conditions posing risks for driving safety. Occupational medicine specialists should look for symptoms of locomotor and sleep-related breathing disorders as these are medical conditions which could preclude a person from driving. In this case report, the authors describe a professional driver with chest deformity and present a pioneering attempt at assessing his medical fitness to drive. It is also explained why scoliosis can impair driving ability and how it should be diagnosed and treated. Finally, the authors describe how they used driving simulator tests as part of their diagnosis and suggest a relevant treatment regimen. Int J Occup Med Environ Health. 2019;32(5):735-45.

Analysis of bus drivers reaction to simulated traffic collision situations - eye-tracking studies.

OBJECTIVES: The aim of the study was to establish whether the driver's visual strategy may influence a driver's behavior to avoid a crash in a high-risk situation. Any published papers on drivers' visual strategies just before a crash were not found. MATERIAL AND METHODS: Tests were performed using a high-tech driving bus simulator. Participants comprised 45 men drivers, aged 43.5±7.9 years old, seniority as a bus driver of 13.3±8.6 years. The tests were preceded by medical examinations: general, neurological and ophthalmological. Each participant drove the same city route for approximately 40 min (entire route - ER). In the final phase, a collision situation was simulated (a phantom car blocked the participant's right of way). Driver's visual strategy was analyzed using the FaceLab device with 2 cameras during ER and just before collision. The field-of-view covered by camera 1 was divided into 8 regions, by camera 2 into 10 regions. The distribution of gazes in regions was a criterion of visual strategy. RESULTS: Thirty-five drivers completed the simulated driving test, 14 escaped the collision, 21 crashed. These groups differed only in resting systolic blood pressure before the test. The analysis of covariance, after adjusting to this factor, indicated that during the ER visual strategy recorded by camera 1 did not differ between groups, in camera 2 the drivers in the crash group fixed their gaze more frequently (p = 0.049) in region 3 (close part of the road in front of the windshield). Just before the collision drivers who escaped the collision fixed their gaze significantly more often in region 6 (left side of the road) in camera 1 and in region 6 (in front of the windshield,) and region 10 (right side) in camera 2. CONCLUSIONS: The visual strategy has an impact on the road safety. The analysis of visual strategies may be a useful tool for the training of drivers. Int J Occup Med Environ Health. 2019;32(2):161-74.

[Work fatigue in urban bus drivers]. / Zmeczenie praca u kierowców autobusów miejskich.

BACKGROUND: Bus drivers are a special group of professional drivers who are at a very high risk of fatigue. The aim of the study was to examine whether the driver's subjective assessment of fatigue allows for the determination of its level and identification of its causes. MATERIAL AND METHODS: The study group comprised 45 randomly selected bus drivers (mean age - 43.7 ± 7.9 years, period of employment as drivers - 14.7 ± 8.6 years). Examinations were performed in all subjects four times - before and after work on the "easy" route (outside the city center, small traffic intensity) and before and after work on the "difficult" route (city center, heavy traffic). The fatigue test questionnaire, based on the list of symptoms of fatigue prepared by the Japan Research Committee of Fatigue, was used in the study. RESULTS: The rating of fatigue after the work was significantly higher than that before the work. The profile of fatigue after work was not influenced by the type of route, but the assessment of most symptoms of fatigue reached a higher level after the "difficult" routes and the differences were statistically significant for 7 symptoms. Only the ratings of leg fatigue, feeling of heaviness, and the necessity to squint eyes and gaze with effort reached the higher levels after driving the "easy" routes. It has been found that the level of fatigue was significantly correlated with the job characteristics (driving time, the length of the route, number of stops, etc.) and with the abundance of food ingested and type of beverage (coffee vs. others) drunk prior to driving. CONCLUSIONS: The questionnaire used in our study to assess the subjective feeling of fatigue has proved to be a sensitive and useful tool for indicating the level and causes of fatigue. The relationship between the symptoms of fatigue and the characteristics of job and lifestyle shows that actions must be taken by both the employers and employees to prevent fatigue in bus drivers.

Application of eye-tracking in the testing of drivers: A review of research.

Recording and analyzing eye movements provide important elements for understanding the nature of the task of driving a vehicle. This article reviews the literature on eye movement strategies employed by drivers of vehicles (vehicle control, evaluation of the situation by analyzing essential visual elements, navigation). Special focus was placed on the phenomenon of conspicuity, the probability of perceiving an object in the visual field and the factors that determine it. The article reports the methods of oculographic examination, with special emphasis on the non-invasive technique using corneal reflections, and the criteria for optimal selection of the test apparatus for drivers in experimental conditions (on a driving simulator) and in real conditions. Particular attention was also paid to the helmet - or glass-type devices provided with 1 or 2 high definition (HD) camcorders recording the field of vision and the direction of gaze, and the non-contact devices comprising 2 or 3 cameras and an infrared source to record eye and head movements, pupil diameter, eye convergence distance, duration and frequency of eyelid blinking. A review of the studies conducted using driver eye-tracking procedure was presented. The results, in addition to their cognitive value, can be used with success to optimize the strategy of drivers training.