Mental workload - 161 entries found
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de Croon E.M., Blonk R.W.B., de Zwart B.C.H., Frings-Dresen M.H.W., Broersen J.P.J.
Job stress, fatigue, and job dissatisfaction in Dutch lorry drivers: Towards an occupation specific model of job demands and control
Based on Karasek's model, this study examined the effects of job control, quantitative workload and occupation-specific job demands on fatigue and job dissatisfaction in Dutch lorry drivers. Information on job control, quantitative workload, physical demands, supervisor demands, fatigue and job dissatisfaction was gathered through questionnaires from 1181 lorry (truck) drivers. Data were subjected to multiple regression analyses. Inclusion of physical and supervisor demands in the model explained a significant amount of variance in fatigue (3%) and job dissatisfaction (7%). Moreover, in accordance with Karasek's interaction hypothesis, job control dampened the positive relation between quantitative workload and job dissatisfaction. The inclusion of occupation-specific job control and job demand factors gives occupational stress researchers a better insight into the relation between the psychosocial work environment and well-being.
Occupational and Environmental Medicine, June 2002, Vol.59, No.6, p.356-361. Illus. 60 ref.
Sebastián García O., del Hoyo Delgado M.Á.
La carga mental de trabajo [in Spanish]
This booklet begins with a definition of mental workload, and proceeds with a description of the determinants of mental workload in occupational settings (job requirements and capacity of the worker to respond), its main characteristics and consequences (fatigue giving rise to decreases and/or errors in performance). Several methods and scales for evaluating mental workload, as well as measures for the prevention of mental fatigue, are also presented. A summary of the ISO 10075 standard on ergonomic principles with respect to mental workload is also included.
Instituto Nacional de Seguridad e Higiene en el Trabajo, c/Torrelaguna 73, 28027 Madrid, Spain, 2002. 51p. 22 ref.
Hidri A., Souissi R., Ben Laiba M.
Ergonomic risks and prevention
Risque ergonomique et prévention [in French]
Contents of this special feature on the prevention of ergonomic risks: general aspects and definitions; objectives of ergonomics; areas of application; contributions of ergonomics in the prevention of occupational hazards; fields that form the basis of ergonomics (anthropometrics, biomechanics, occupational physiology, working environment analysis; experimental psychology; psycho-sociology); ergonomic approach; ergonomic workplace design; mental workload.
SST - Santé et Sécurité au Travail, Jan. 2002, No.20, p.2-21. Illus. 21 ref.
Associations between workload and diseases rarely occurring in sickness absence data
This study investigates the relationship between sickness absenteeism in Germany and workload accessed by means of a job exposure matrix, with an emphasis on diseases that are seldom studied by sickness absenteeism data either because the incidence is low or because rest from work is not prescribed in the medical treatment. 42,508 employees from the metal processing industry and the retail sector were followed for three years. Sick leave related to hypertension, ischaemic heart diseases, ulcers, neurotic disorders and work accidents was most frequent in employees exposed to physical demands and low control. In contrast, an inverse relation was observed for psychological demands, for which ratios decreased with increasing exposure. This finding might be an expression of work commitment or pressure to attend rather than of coping behaviour.
Journal of Occupational and Environmental Medicine, Dec. 2001, Vol.43, No.12, p.1081-1088. 19 ref.
de Arquer M.I., Nogareda C.
Mental workload: Indicators
Carga mental de trabajo: indicadores [in Spanish]
Although there is no single approach for assessing mental workload given the wide variety of working conditions, this information note proposes a general framework that can be used as a guide for developing an assessment approach for specific conditions. This framework consists of the following steps: data collection; description of the workplace, working conditions and profiles of persons assigned to the work; assessment of the mental requirements (or pressures), and resulting tensions; proposals for improvement, their selection and implementation.
Instituto Nacional de Seguridad e Higiene en el Trabajo, Ediciones y Publicaciones, c/Torrelaguna 73, 28027 Madrid, Spain, 2000. 6p. Illus. 16 ref.
Sluiter J.K., Frings-Dresen M.H.W., van der Beek A.J., Meijman T.F., Heisterkamp S.H.
Neuroendocrine reactivity and recovery from work with different physical and mental demands
Neuroendocrine reactivity and recovery were studied by measuring the urinary excretion of adrenaline, noradrenaline and cortisol during and after three workdays and during and after two consecutive days off. The fifth day, or second day off, was considered baseline. The assessment was made in 60 Dutch male workers divided into three groups according to the mental, physical, and combined mental and physical demands of their work. Differences in main or interaction effects with time of day were found between the workers in combined mental and physical work and the two other groups of workers for cortisol, adrenaline and noradrenaline excretion. In addition, the baseline levels of the 3 hormones were higher in the workers with combined mental and physical work. Unfavourable effects on cortisol and adrenaline reactivity or recovery was found for workers with combined mental and physical demands when compared with workers doing mainly mental or mainly physical work. The results of the present study are in accordance with the cognitive activation theory and the allostatic load model.
Scandinavian Journal of Work, Environment and Health, Aug. 2000, Vol.26, No.4, p.306-316. Illus. 39 ref.
de Arquer I., Nogareda C.
Mental workload assessment: the NASA TLX method
Estimación de la carga mental de trabajo: el método NASA TLX [in Spanish]
This information note describes the NASA TLX method, which consists of a tool to assist in the diagnosis of mental workload. It is based on a multidisciplinary evaluation of six factors (mental demands, physical demands, temporal demands, effort, performance and frustration level). Contents: definition of mental and physical demands; evaluation of mental workload and mental fatigue (mental fatigue indicators, mental workload factors at the workplace, subjective methods); description of the NASA TLX method and its advantages; example of an application.
Instituto Nacional de Seguridad e Higiene en el Trabajo, Ediciones y Publicaciones, c/Torrelaguna 73, 28027 Madrid, Spain, 2000. 6p. Illus. 13 ref.
Conditions for maintaining ageing operators at work - A case study conducted at an automobile manufacturing plant
The relationship between mental workload and ageing in an automobile manufacturing company was investigated. Demographic trends and work organization determine the conditions under which older workers can work in repetitive tasks under tight time constraints. The methodology is based on comparing workers of different ages at their regular workstations and during the training process for conducting new tasks. The older workers appear to develop health-preserving approaches to work while achieving production goals. The possibility of setting up such strategies depends on the task characteristics. More generally, this study allows a better understanding of why some older workers are excluded from certain tasks, and thus why "polyvalency" or job rotation decreases with age.
Applied Ergonomics, Oct. 2000, Vol.31, No.5, p.453-462. Illus. 15 ref.
Xie B., Salvendy G.
Review and reappraisal of modelling and predicting mental workload in single- and multi-task environments
In the mental-workload literature, few predictive models have considered factors specific to individuals. This research proposes a practical framework for predicting mental workload in both single- and multi-task environments considering such individual factors. In order to describe mental workload more precisely and more completely, a framework for mental-workload definitions, which contains instantaneous workload, average workload, accumulated workload, peak workload and overall workload, is proposed. In order to model individual factors, two new variables, effective workload and ineffective workload, are introduced to model the task-generated workload and individual-generated workload. The extension of the model to multi-task environments is also discussed. The proposed conceptual models are domain-independent and could be used to guide the development of operational models for different specific tasks.
Work and Stress, Jan.-Mar. 2000, Vol.14, No.1, p.74-99. Illus. 69 ref.
Bliese P.D., Castro C.A.
Role clarity, work overload and organizational support: Multilevel evidence of the importance of support
This study extended the demands-control-support model used in occupational stress research in two ways. Firstly, it hypothesized that role clarity (or role ambiguity), like control, would moderate the relationship between demands and psychological strain. Secondly, the study assessed support (from leaders) as a macro characteristic of the work-group environment. Data were drawn from a large study of US army soldiers, the study sample consisting of 1,786 lower enlisted male soldiers. The inclusion of support as a work-group characteristic lead to a multilevel test of the model. A three-way multilevel interaction among work demands, role clarity and support was observed. As predicted, the relationship between demands and psychologicalstrain was moderated by role clarity; however, this moderating relationship was found only when work-group support was high.
Work and Stress, Jan.-Mar. 2000, Vol.14, No.1, p.65-73. Illus. 26 ref.
Söderfeldt M., Söderfeldt B, Ohlson C.G., Theorell T., Jones I.
The impact of sense of coherence and high-demand/low-control job environment on self-reported health, burnout and psychophysiological stress indicators
The Job Demand-Control (JDC) model of job stress suggests that the combination of high job demands and low job control, defined as job strain, is strongly associated with adverse health consequences. The aim of this study was to evaluate the relationship between Sense of Coherence (SOC) and the JDC model in assessment of negative job effects within three pathogenically defined contexts: self-reported health, burnout and psychophysiological stress indicators, assessing the explanatory value of SOC for such variables. The study was conducted with 103 employees of social-welfare and social-insurance agencies in Sweden. A questionnaire related to job conditions, health and burnout was administered, and blood samples were collected and analysed for serum concentrations of cortisol, prolactin and immunoglobulin G. It is concluded that studies of job strain-effects according to the JDC model should include the SOC as an interaction factor.
Work and Stress, Jan.-Mar. 2000, Vol.14, No.1, p.1-15. 40 ref.
Konradt U., Schmook R.
Analysis of stress and strain in teleworking
Analyse der Belastungen und Beanspruchungen an Telearbeitsplätzen [in German]
Preliminary results of the first part of a longitudinal study on teleworking are presented. Stresses and strains were studied for 33 workplaces at home or alternating between the office and the home, and for 13 reference workplaces offering a similar workload. Results indicate that stresses and strains of teleworking do not fundamentally differ from those of the reference workplaces. Persons working at home have more flexibility in organizing their work. A negative correlation was observed between irritation and workload and general work satisfaction.
Arbeit - Zeitschrift für Arbeitsforschung, Arbeitsgestaltung und Arbeitspolitik, 1999, Vol.8, No.1, p.40-58. Illus. 36 ref.
de Arquer M.I.
Mental workload: Factors
Carga mental de trabajo: factores [in Spanish]
This information note defines mental workload and describes the main contributing factors, which include: job demand; conditions of work (lighting, thermal comfort, noise level, work atmosphere, unpleasant smells, social and organizational factors), personal factors and non-occupational social factors. The negative consequences of an excessive mental workload are explained, and preventive measures are proposed.
Instituto Nacional de Seguridad e Higiene en el Trabajo, Ediciones y Publicaciones, c/Torrelaguna 73, 28027 Madrid, Spain, 1999. 5p. 6 ref.
Devereux J.J., Buckle P.W., Vlachonikolis I.G.
Interactions between physical and psychosocial risk factors at work increase the risk of back disorders: An epidemiological approach
Manual workers, delivery drivers, technicians, customer services, computer operators and general office staff reported risk factors at work and back disorders with a self administered questionnaire. The workers were classified into high physical and high psychosocial; high physical and low psychosocial; low physical and high psychosocial; and low physical and lowpsychosocial exposure groups. Low physical and low psychosocial was used as an internal reference group. Exposure criteria were derived from existing epidemiological publications and models for physical and psychosocial work factors. Frequency and amplitude of lifting and the duration spent sitting while experiencing vibration were used as physical exposure criteria. Ordinal values of mental demands, job control and social support from managers and coworkers were used as psychosocial exposure criteria. The highest increase in risk was found in the high physical and high psychosocial group for back disorders. This study suggests that an interaction between physical and psychosocial risk factors at work may exist and that the greatest benefits are when both physical and psychosocial factors are put right.
Occupational and Environmental Medicine, May 1999, Vol.56, No.5, p.343-353. Illus. 75 ref.
The mental workload of work is increasing
La pénibilité mentale du travail augmente [in French]
According to a survey conducted in 1998 by the French Ministry of Employment, occupational mental workload has increased when compared to the results of a similar survey conducted in 1991. One employee in four claims not to have enough time to do their work. Topics covered: perceived risk of penalty in the case of errors; work rhythms; noise exposure; indicators of occupational mental workload; frequency of task interruptions in favour of more urgent tasks; bullying at work; conflicts with superiors or co-workers.
Travail et sécurité, Oct. 1999, No.589, p.8-10. Illus. 3 ref.
Lin D.Y., Hwang S.L.
Use of neural networks to achieve dynamic task allocation: A flexible manufacturing system example
In order to attain optimum performance of automated systems, task allocation between humans and computers becomes very important. However, a critical problem existing in the technology of dynamic task allocation is how to develop an implicit human-computer communication interface. Two models, that of "neural networks" and of the "predictive method", are proposed for the allocation of tasks between humans and computers. The first phase of the study was to find important and sensitive indexes to measure the mental workload in supervisory tasks through the use of a multiple regression equation. The second phase was to construct a programming system in an FMS to evaluate the workload index and allocate the task dynamically through the application of the back propagation network (BPN) and the predictive values of the multiple regression equation. Participants were divided into two groups, dynamic and static. The result showed that the workload of the dynamic group was significantly lower than the static group. The neural network proved to be an effective method for decreasing the mental workload through dynamic task allocation.
International Journal of Industrial Ergonomics, June 1999, Vol.24, No.3, p.281-298. Illus. 48 ref.
Eriksen H.R., Ursin H.
Subjective health complaints: Is coping more important than control?
In a study involving 1,060 Norwegian postal workers with high work demand, the interrelations of psychological demands, control, coping, job stress and subjective health complaints were examined. A demand-coping model was developed and compared with the traditional demand-control model. Coping, understood as the expectancy of positive outcomes, was found to have more impact than control (decision latitude). Subjective health complaints were found to depend more on combinations of demands and coping than on demands and control. Individual coping mechanisms were found to be more important for subjective health than organization factors.
Work and Stress, July-Sep. 1999, Vol.13, No.3, p.238-252. Illus. 43 ref.
Taris T.W., Schreurs P.J.G., Schaufeli W.B.
Construct validity of the Maslach Burnout Inventory-General Survey: A two-sample examination of its factor structure and correlates
The Maslach Burnout Inventory-General Survey, an instrument for the measurement of burnout in professions not involving contacts with persons, was validated in a study involving 179 software engineers and 284 university staff members. With respect to internal validity, the distinction of three burnout subscales is retained. With respect to external validity, the meaning of the subscales in terms of selected work characteristics is quite different. For practical purposes, burnout scores can readily be obtained in a one-dimensional concept; for scientific purposes, burnout should be scored in three different dimensions.
Work and Stress, July-Sep. 1999, Vol.13, No.3, p.223-237. Illus. 48 ref.
Hacker W., Reinhold S.
Assessment of the workload of nursing tasks with the objective of improving work organization
Beanspruchungsanalysen bei Pflegetätigkeiten zur Abteilung arbeitsorganisatorischer Verbesserungsmöglichkeiten [in German]
Topics: hazard evaluation; health care personnel; hospitals; human relations; job dissatisfaction; job study; mental workload; motivation; neuropsychic stress; physical workload; work organization.
Zeitschrift für Arbeitswissenschaft, May 1998, Vol.52, No.1, p.7-14. Illus. 30 ref.
Borsch-Galetke E., Struwe F.
Mental stress and strain in the light of changes in the working world and environment; Carcinogenesis and cocarcinogenesis - Colloqium on Occupational Medicine organized by the Mutual of Industrial Accident Insurance Associations
Psychomentale Belastungen und Beanspruchungen im Wandel von Arbeitswelt und Umwelt; Kanzerogenese und Synkanzerogenese - Arbeitsmedizinsches Kolloquium der gewerblichen Berufsgenossenschaften [in German]
Proceedings of a symposium on occupational medicine, with special attention paid to mental stress and strain and to carcinogenesis, held in Wiesbaden, Germany, 12-15 May 1997. The main topics under which papers were presented were: psychological stress and strain; carcinogenesis and carcinogens; radiation and lung cancer issues at the WISMUT uranium trust in former East Germany; automobile exhaust gases and pyrolysis products; whole-body vibration; Helicobacter pylori infection among student nurses; lung function measurement; work physiology, work psychology and performance evaluation; solvents (with emphasis on ethylene oxide); metals and waste materials; women at work; the environment and the working environment; problems of the spine; toxicity tests; metal toxicity; occupational problems affecting the urogenital system; allergies and infections; the respiratory tract.
Institut für Arbeitsmedizin der Medizinischen Universität zu Lübeck, Ratzeburger Allee 160, 23538 Lübeck, Germany, 1997. 701p. Illus. Bibl.ref. Index.
de Arquer M.I.
Mental workload: Fatigue
Carga mental de trabajo: fatiga [in Spanish]
Topics: data sheet; diet; mental workload; motivation; nervous fatigue; physical fitness; sickness absenteeism; Spain; workbreaks.
Instituto Nacional de Seguridad e Higiene en el Trabajo, Ediciones y Publicaciones, c/Torrelaguna 73, 28027 Madrid, Spain, 1997. 4p. 12 ref.
Martín Daza F., Pérez Bilbao J.
Psychosocial factors: Assessment methodology
Factores psicosociales: metodología de evaluación [in Spanish]
Topics: data sheet; description of technique; fatigue; human factors; human relations; job dissatisfaction; mental stress; mental workload; psychology of work organization; Spain.
Instituto Nacional de Seguridad e Higiene en el Trabajo, Ediciones y Publicaciones, c/Torrelaguna 73, 28027 Madrid, Spain, 1997. 6p. 3 ref.
Doppler F., Falzon P.
Stress induced by mental work
Astreinte induite par le travail mental [in French]
Replaces CIS 87-1111. Topics: encyclopaedia; fatigue; human failure; literature survey; man-machine interfaces; mental stress; mental work; mental workload; stress evaluation; stress factors; subjective assessment; visual tasks.
Encyclopédie médico-chirurgicale, Toxicologie-Pathologie professionnelle, 2nd Quarter 1997, No.115, 6p. Illus. 20 ref.
Seppälä P., Luopajärvi T., Nygård C.L., Mattila M.
From experience to innovation - IEA '97: Volume 5 - Human computer interaction, stress and mental load, aging and occupational health
Proceedings of the 13th Triennial Congress of the International Ergonomics Association held in Tampere, Finland, 29 June-4 July 1997. Volume 5 covers: human computer interaction (design of workstations for work with visual display units, design, interface and software design); mental load, stress and well-being (psychophysiological mesurements); ergonomics in relation to ageing and work; and occupational health issues. Topics: ageing; biological effects; computer terminals; conference; ergonomics; Finland; keyboard operations; man-computer interfaces; mental stress; mental workload; older workers; plant health supervision; social aspects; visual comfort; visual displays; work capacity; work design; work posture; workplace design.
Finnish Institute of Occupational Health, Publication Office, Topeliuksenkatu 41 a A, 00250 Helsinki, Finland, 1997. xiv, 707p. Illus. Bibl.ref.
Guyomard A., Gauterand D., Longueville J.M.
Study of the mental workload of educators
Etude de la charge mentale des éducateurs [in French]
Topics: conditions of work; educational institutions; France; mental stress; mental workload; questionnaire survey; stress evaluation.
Cahiers de médecine interprofessionnelle, 1997 No.2, p.165-171. 8 ref.
Jex S.M., Adams G.A., Elacqua T.C., Lux D.J.
A comparison of incident-based and scale measures of work stressors
Topics: human relations; job dissatisfaction; mental stress; mental workload; stress factors; stress studies; subjective assessment.
Work and Stress, July-Sep. 1997, Vol.11, No.3, p.229-238. 36 ref.
Williams S.N., Crumpton L.L.
Investigating the work ability of older employees
The work ability index developed by the Finnish Institute of Occupational Health was used to assess the work ability of 20 university employees aged from 50 to 55. Participants were asked to respond to questions concerning their physical, mental and social capacities. The work ability values of these employees were slightly higher than the reference values developed from previous research studies. The method may be used to estimate the work capacity of older employees and to determine required modifications in equipment design or working conditions.
International Journal of Industrial Ergonomics, Sep. 1997, Vol.20. No.3, p.241-249. 7 ref.
Mechanised cleaning of young forest - The strain on the operator
This study is an ergonomic analysis of forestry operations by means of cleaning and spacing machines. It was conducted measuring the workload and assessing the difficulties and possible improvements in the efficiency of the operations. A low heart rate variability was found in the operators, indicating a high mental workload. The operation of the machine crane does not allow pauses in the trapezius muscles activity, as shown by electromyography. Neck and shoulder pain is also common. Productivity limitations associated with operators are emphasized, envisaging future modified machines or even autonomous robots to carry out the same work.
International Journal of Industrial Ergonomics, Aug. 1997, Vol.20, No.2, p.137-143. Illus. 15 ref.
de Zwart B.C.H., et al.
Occupational classification according to work demands: An evaluation study
An existing occupational classification scheme based on six categories of physical and mental work demands and a revised version of the scheme with only four categories were evaluated. Self-reported work demands obtained from a questionnaire survey of 38,921 employees were quantified according to a scale of physical and mental work demands. On the basis of the mean scale scores at group level, both classification schemes showed validity. Classification of jobs into broad categories with similar work demands may be useful in studies of patterns of work-related disorders.
International Journal of Occupational Medicine and Environmental Health, 1997, Vol.10, No.3, p.283-295. Illus. 31 ref.
Bundesanstalt für Arbeitsmedizin
Occupational health and safety aspects of stress at modern workplaces
Topics: adrenal function; assembly-line work; cash registers; conference; fatigue; Germany; human relations; job study; mental stress; mental workload; musculoskeletal diseases; Netherlands; physical workload; pituitary function; questionnaire survey; social aspects; stress evaluation; supermarkets; work organization.
Wirtschaftsverlag NW, Verlag für neue Wissenschaft GmbH, Postfach 10 11 10, 27511 Bremerhaven, Germany, 1996. 121p. Illus. Bibl. ref.
Rahill A.A., Weiss B., Morrow P.E., Frampton M.W., Cox C., Gibb R., Gelein R., Speers D., Utell M.J.
Human performance during exposure to toluene
Six adults were exposed to either conditioned room air or 100ppm toluene for 6h, including 30min of exercise. Physiological and neuropsychological assessments were carried out. Following exercise, the mean blood and exhaled air toluene levels averaged 1.5µg and 28ppm respectively; lung function was unchanged post-exposure. Both the brief neuropsychological tests and the prolonged multitask performance tests detected an effect of toluene. Differences in performance between air and toluene conditions were greatest after exercise, indicating that physical activity may enhance the response to volatile organic solvents.
Aviation, Space, and Environmental Medicine, July 1996, Vol.67, No.7, p.640-647. 20 ref.
Ergonomic principles related to mental workload - Part 2: Design principles
Principes ergonomiques relatifs à la charge de travail mental - Partie 2: Principes de conception [in French]
Part 2 of this international standard provides guidance on the design principles of work systems, including task and equipment design and design of the workplace, as well as working conditions, emphasizing mental workload and its effects as specified in ISO 10075. This part of the standard does not address problems of measurement of mental workload or of its effects. Contents: scope; normative references; definitions; design principles: general principles, guidelines concerning fatigue, monotony, reduced vigilance, satiation; information and training. Annex: examples of design solutions (informative).
International Organization for Standardization, Case postale 56, 1211 Genève 20, Switzerland, 1996. iv, 11p.
Stress during work on with VDUs - Approaches for a system-oriented analysis of stress perceptions when working with computers
Stress am Bildschirmarbeitsplatz - Ansätze zu einer systemorientierten Analyse des Stresserlebens bei der Arbeit mit dem Computer [in German]
Topics: computers; CRT display terminals; ergonomics; mental workload; psychology and sociology; stress evaluation; stress factors; stress studies.
Verlag Dr. Kovač, Postfach 50 08 47, 22708 Hamburg, Germany, 1995. iv, 200p. Illus. 177 ref.
The prevalence of occupational overuse syndrome among Australian Sign Language interpreters
A questionnaire survey was conducted in order to determine the prevalence of occupational overuse syndrome (OOS) in 104 Australian Sign Language (Auslan) interpreters. Among diagnosed conditions: carpal tunnel syndrome, ulnar nerve entrapment, epicondylitis and other upper extremities disorders were reported. Several hypotheses were put forward to explain the incidence of OOS, reaching the conclusion that the group most at risk is that of full-time sign-language interpreters employed for more than four years. Suggestions are as to how to avoid the further spread of OOS in this occupational group.
Journal of Occupational Health and Safety - Australia and New Zealand, June 1995, Vol.11, No.3, p.257-263. 14 ref.
Frauendorf H., Caffier G., Kaul G., Wawrzinoszek M.
Bundesanstalt für Arbeitsmedizin
Investigation for recording and assessing the combined physical and mental loads on the cardiac system
Modelluntersuchung zur Erfassung und Bewertung der Wirkung kombinierter physischer und psychischer Belastungen auf Funktionen des Herz-Kreislauf-Systems [in German]
The aim of the investigation was to find out the influence of combined physical and mental load on the activity of the cardiovascular and motor system. Under all tested conditions of the study, there was an increase, with some hyperreactive subjects, of heart rate and arterial blood pressure as well as of the bioelectrical activity of the tested muscles. In the long-term, this could be a risk factor for cardiovascular disorders as well as disorders of the shoulder-arm region. Summary in English.
Wirtschaftsverlag NW, Postfach 10 11 10, 27511 Bremerhaven, Germany, 1995. 51p. Price: DEM 15.50
Rau R., Richter P.
Bundesanstalt für Arbeitsmedizin
24-hour monitoring to check the reactivity of psychophysiological parameters during periods of mental work and rest
24-Stunden-Monitoring zur Prüfung der Reaktivität psychophysiologischer Parameter in Belastungs- und Erholungsphasen [in German]
Pulse rate, blood pressure and sodium and potassium levels in saliva were monitored in 48 healthy students during a 24-hour period, while they maintained their normal activities (attending classes, sleeping). Some students were monitored during a second 24-hour period in which they took an examination. The strongest correlations were found between mental workload on one hand and pulse rate and blood pressure on the other. For the salivary potassium level the correlation was weaker while the sodium levels did not at all reflect short-term changes in the mental workload.
Wirtschaftsverlag NW, Postfach 10 11 10, 27511 Bremerhaven, Germany, 1995. 106p. Illus. 148 ref. Price: DEM 12.50.
Bi S., Salvendy G.
A proposed methodology for the prediction of mental workload, based on engineering system parameters
A conceptual model for the prediction of mental workload in system design is proposed. In this model, workload is represented by a set of system parameters (task arrival rate, task complexity, task uncertainty and performance requirements) which are considered to be the main sources of workload. Whether an individual or population is overloaded depends on their workload threshold with respect to the specified task and environment. It is hoped that this model, after laboratory and industrial validation, may be used by system engineers to predict the workload imposed on people by systems.
Work and Stress, Oct.-Dec. 1994, Vol.8, No.4, p.355-371. 37 ref.
Freude G., Ullsperger P.
Bundesanstalt für Arbeitsmedizin
Analysis of mental workload with the help of parameters of bioelectrical brain activity
Analyse psychischer Beanspruchung anhand von Parametern der bioelektrischen Hirnaktivität [in German]
The readiness potential (Bp) derived from the event-related bioelectrical brain activity recorded by electroencephalography was found to be a measure of mental effort and mental fatigue. This result was obtained from experiments during which young, healthy volunteers performed three different tasks on the computer. The first task involved the repetitive addition and subtraction of numbers and the comparison of end-results. The second task required the memorizing of words that appeared on the visual display unit and typing the memorized words into the computer. The third task was to check the spelling of words in a text that appeared on the visual display unit.
Wirtschaftsverlag NW, Postfach 10 11 10, 27511 Bremerhaven, Germany, 1994. 58p. Illus. 42 ref.
Cloutier E., Dubucs B.
Study of the real workload of home nursing assistants
Etude du travail réel des aides-soignantes à domicile [in French]
Health problems of home nursing assistants are not well known because their working conditions are rather special (work in isolation, organizational problems). A prolonged observation of the real workload of these workers was carried out together with interviews. Back and fatigue problems were associated with forced postures during patient care. The heavy workload, partly due to the lack of adequate equipment, is compounded by the mental workload not formally recognized by the people responsible for work organization. This mental load does not only result from time pressures requiring frequent reorganization of working time but is also related to the emotional involvement while providing support to the patient and his family. The possibility of lightening certain tasks by changing work organization and planification of this category of workers is underlined.
Archives des maladies professionnelles et de médecine du travail, 1994, Vol.55, No.4, p.269-277. 20 ref.
Wærsted M., Bjørklund R.A.
The effect of motivation on shoulder-muscle tension in attention-demanding tasks
In four separate experiments using a visual display unit based complex reaction-time task, motivation was induced by means of continuous feedback on the level of performance or by means of a money reward for good performance. In all experiments, motivation improved the performance, but an increase in the psychogenic shoulder-muscle tension was only observed in the money-reward condition. Results are discussed in terms of whether this difference in the muscle-tension response is due to changes in the subjects' attitude unrelated to performance or due to a superior performance in the money-reward condition.
Ergonomics, Feb. 1994, Vol.37, No.2, p.363-376. Illus. 32 ref.
Humphrey D.G., Kramer A.F.
Toward a psychophysiological assessment of dynamic changes in mental workload
The feasibility of using event-related brain potentials (ERPs) to measure dynamic changes in mental workload was examined. Subjects performed two tasks, monitoring and mental arithmetic, both separately and together. An analysis was made of performance, subjective workload ratings and average ERP data as measured from recordings of electroencephalographic activity. The data are discussed with respect to real-time assessment of mental workload. Results provide tentative support for the use of ERPs as measures of momentary fluctuations in mental workload.
Human Factors, Mar. 1994, Vol.36, No.1, p.3-26. Illus. 57 ref.
Berg J.E., Høstmark A.T.
Workload and cardiovascular risk factors in executives and non-executives of the same company
Aspects of lifestyle and cardiovascular (CV) risk factors in blood were compared in 22 executives and a matched sample of non-executives in an insurance company in Norway. Executives travelled more and worked more hours than non-executives, but smoking habits, levels of physical activity, diet habits and blood pressure were comparable in the two groups, as were coronary risk indicators in blood. While results suggest that the executive lifestyle is not associated with an elevated CV risk, the high levels of total cholesterol and of a compound atherogenic index in both groups suggest that continued action by the occupational health service is required.
Occupational Medicine, May 1994, Vol. 44, No.2, p.87-90. 20 ref.
Myrtek M., Deutschmann-Janicke E., Strohmaier H., Zimmermann W., Lawerenz S., Brügner G., Müller W.
Physical, mental, emotional, and subjective workload components in train drivers
Simultaneous recording and on-line analysis of heart rate and physical activity separated the emotional component from the physical in terms of the so-called additional heart rate. Mental workload was estimated by the heart rate variability and from shifts in the T-wave amplitude of the electrocardiogramme, while the speed of the train, the mode of driving, and the stressfulness of the situation were rated by two observers who accompanied the drivers in the cab. At speeds up to 100km/h no heart rate changes occurred, but as speed increased from 100km/h to 200km/h, the heart rate decreased, indicating a monotony effect. However, heart rate variability and T-wave amplitude indicated higher mental load during driving in most speed categories. Starting the train and coming to a halt showed greater emotional workload than moving. Observers' rating of stress and subjective rating of stress by the drivers showed several discrepancies. Discrepancies were also seen between workload as indicated by the physiological parameters and corresponding stress ratings by the observers or by drivers.
Ergonomics, July 1994, Vol.37, No.7, p.1195-1203. Illus. 22 ref.
Workload and psychophysiological stress reactions in air traffic controllers
Interactions between workload and psychophysiological stress symptoms were investigated in a population of 205 air traffic controllers (ATCs) from Zurich and Geneva. Results of a questionnaire survey showed that about 10 to 15% of the ATCs showed elevated values in psychological stress symptoms to an extent indicating that they might have serious stress problems. Results of investigated working sessions showed that subjective ratings corresponded clearly to cortisol response and the objective workload. Results confirm the idea that the job of an ATC is demanding but not necessarily more stressful than jobs of similar demands; complaints about excessive workload should be taken seriously.
Ergonomics, Mar. 1994, Vol.37, No.3, p.525-539. Illus. 45 ref.
Brenner M., Doherty E.T., Shipp T.
Speech measures indicating workload demand
Heart rate and six speech measures were evaluated for 17 male subjects performing three task trials of varying difficulty. Heart rate, speaking fundamental frequency (pitch) and vocal intensity (loudness) increased significantly with workload demands. A derived speech measure which statistically combined information from other speech measures was also evaluated. It increased significantly with workload demands and reflected differences among individual subjects better than any of its component measures. It appears that speech analysis can provide a practical means of stress assessment.
Aviation, Space, and Environmental Medicine, Jan. 1994, Vol.65, No.1, p.21-26. Illus. 18 ref.
Tarumi K., Hagihara A., Morimoto K.
An inquiry into the relationship between job strain and blood pressure in male white-collar workers
Published studies of the relationship of psychosocial factors at work with hypertension show both positive and negative correlations. A cross-sectional study to investigate the relationship between psychological load and blood pressure was conducted among white-collar employees of a company in Japan in June 1991. Eligible male subjects (386 normotensives and 75 hypertensives) were analyzed by logistic regression analysis. The correlation was negative: in the case of high job strain, the prevalence of hypertension was low. Those having family history of hypertension tended to have a non-complaining attitude (a fact observed in studies elsewhere) and this seemed to be the reason for the present results.
Japanese Journal of Industrial Health - Sangyō-Igaku, 20 July, 1993, Vol.35, No.4, p.269-276. 28 ref.
Aging and working capacity - Report of a WHO Study Group
Report of a WHO Study Group on Aging and Working Capacity which met in Helsinki, Finland, 11-13 December 1991. Contents: aging population demographics; physiological changes with age; age and job performance; health of the aging worker (mortality, morbidity, disability and poor work ability); working conditions of the aging worker; the aging worker in special work environments (heat, cold, shiftwork); aging and work accidents; health promotion (lifestyle factors, ergonomics); supporting work capacity as workers age. The report concludes with a number of recommendations.
World Health Organization, Distribution and Sales Service, 1211 Genève 27, Switzerland, 1993. vi, 51p. 20 ref. Price: CHF 10.00 (CHF 7.00 in developing countries).
Hendy K.C., Hamilton K.M., Landry L.N.
Measuring subjective workload: When is one scale better than many?
Data from four independent studies on the measurement of workload in a variety of aviation-related situations are examined. The results support the conclusion that a univariate rating of workload is generally a more sensitive measure of information-processing demands than are linear composites of several individual workload-related factors. Further, if a univariate workload rating is not available, a good estimate can be obtained from the unweighted average of the individual factors.
Human Factors, Dec. 1993, Vol.35, No.4, p.579-601. 50 ref.
Hancock P.A., Caird J.K.
Experimental evaluation of a model of mental workload
The proposed model predicts that mental workload grows as perceived distance from a task goal increases and the effective time for action decreases. The model was tested with a microcomputer program that requires a person to move a pointer on the screen to a given location, subject to a time limit and other conditions. The results supported the model, showing good correlation of quantitative measures of performance with subjective ratings of workload.
Human Factors, Sep. 1993, Vol.35, No.3, p.413-429. Illus. 40 ref.
Laflamme L., Friedrich P.
Institut de recherche en santé et en sécurité du travail du Québec (IRSST)
Patterns in task demands and in occupational accidents: A relationship investigated in the Swedish sawmill industry
Job demand characteristics of tasks in nine trimming houses were gathered using two task analysis methods involving worker observation and interviews. The relationship between task patterns and accident frequency, severity and types was measured. Results indicated that the tasks' mental loads can quite likely influence accident occurrence: accidents are more likely to occur in tasks that are heavily hindered, with numerous interruptions and impediments of various kinds. It is stressed that improving safety is also feasible and achievable through interventions focussing on work content and not only on work performance. Summary in Swedish.
Arbetsmiljöinstitutet, Förlagstjänst, 171 84 Solna, Sweden, 1993. 70p. 26 ref.
Ramsey J.D., Kwon Y.G.
Recommended alert limits for perceptual motor loss in hot environments
Research concerning the effects of heat on task performance has been extensive and contradictory. This paper summarizes more than 150 studies where performance has been reported as a function of temperature, exposure time and type of tasks. It suggests that prediction of performance loss first requires categorizing the type of tasks since mental or very simple tasks typically show little decrement in the heat and are frequently enhanced during brief exposures. Other perceptual motor tasks collectively depict a pattern of onset of performance decrement in the 30°C-33°C WBGT temperature range, and the decrement appears to be relatively independent of exposure time. This is the same temperature range as that associated with the onset of physiological heat stress for the worker performing sedentary or very light work. It appears that performance decrement may be better explained by body temperatures, as indicated by the head or blood temperature, than by the deep body temperature.
International Journal of Industrial Ergonomics, May 1992, Vol.9, No.3, p.245-257. Illus. 78 ref.
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