Mental workload - 161 entradas encontradas
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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.
Nogareda Cuixart C.
Carga mental en el trabajo hospitalario: guía para su valoración
En el sumario de esta nota informativa sobre la evaluación de la carga mental entre el personal sanitario: concepto de carga mental y técnica de evaluación; factores de la carga mental en el trabajo hospitalario (factores relacionados con la actividad laboral, con la organización del trabajo y con los horarios); lista de control para la evaluación de la carga mental; aplicación del método. Tablas ilustrativas sobre este tema.
Instituto Nacional de Seguridad e Higiene en el Trabajo, Ediciones y Publicaciones, c/Torrelaguna 73, 28027 Madrid, Espańa, 1991. 6p. 12 ref.
Kamal A.A.M., Dammak M., Caillard J.F., Couzinet M., Paris C., Ragazzini I.
Relative cardiac cost and physical, mental and psychological work load among a group of post-operative care personnel
Continuous registration of heart rate and observation of all physical, mental and psychological job-related events were carried out in nine post-operative care personnel. The relative cardiac cost (RCC) correlated significantly with the observed work events. The magnitude of participation of work elements in the changes in RCC varied in the subjects according to the type and magnitude of the different work events. However, collective data on the group indicated that changes in RCC were related mainly to physical effort and psychological reaction. The results indicated the possibility of using the heart rate in monitoring working conditions and in guiding their improvement.
International Archives of Occupational and Environmental Health, 1991, Vol.63, No.5, p.353-358. Illus. 27 ref.
This textbook approaches the subject of multiple-task performance from a human factors perspective with an emphasis on practical problems and applied research. There are 4 parts: Part 1 concerns theories of multiple-task performance and provides an overview of the types of models used to describe it; Part 2 concerns learning and performance and includes chapters on learning and motor performance; Part 3 covers mental workload and assessment techniques; Part 4 discusses individual differences and age-related factors.
Taylor and Francis Ltd., Rankine Road, Basingstoke, Hants RG24 OPR, United Kingdom, 1991. xi, 469p. Illus. Bibl.ref. Index. Price: GBP 49.00.
Logeay P., Gadbois C.
Mental strain due to dangerous work situations
Les astreintes psychiques des situations dangereuses de travail [en francés]
The question of dangerous work situations has been dealt with mainly from the point of view of their physical consequences, i.e. occupational accidents. This article takes another approach, by taking into account the complexities of real-life situations, in particular the severity of the danger and its repercussions on the individual. The evaluation of the psychological effects of dangerous work situations poses some theoretical and practical problems which are dealt with successively: appreciation of the danger of a situation, expressions and non-expressions of fear in dangerous situations (concept of the defensive attitudes of a profession).
Documents pour le médecin du travail, 4th Quarter 1990, No.44, p.397-401. 23 ref.
Eilers K., Nachreiner F., Böning E.
Subjective scaling of mental workload. Part 2: Testing the validity of standardised judgements in a field study
Zur subjektiven Skalierung psychischer Beanspruchung. Teil 2: Überprüfung der Validität verankerter Relativurteile in einer Felduntersuchung [en alemán]
The usefulness of rating scales in assessing the mental workload was studied with 40 persons performing 4 different sorting and inspection tasks. The ratings by the test persons did not agree with the ratings by experts of the workload involved in the assigned tasks. A simultaneously used questionnaire assessing 4 aspects of mental strain (fatigue, tension, capability and motivation) did not provide any better agreement. The reasons are discussed.
Zeitschrift für Arbeitswissenschaft, 1990, Vol.44, No.1, p.24-29. Illus. 38 ref.
Approaches to the assessment of mental workload and mental work-related stress
Zugangswege zur Bewertung psychischer Belastungen und Beanspruchungen im Arbeitsprozess [en alemán]
Technological innovations have increased mental workload and mental stress. This has led to a need for assessment methods taking account of this fact. The development of such methods is described. Psychological methods which have proved useful are listed.
Zeitschrift für Arbeitswissenschaft, 1990, Vol.44, No.1, p.1-5. 32 ref.
Beerman B., Kylian H., Schmidt K.H., Klimmer F., Kramer H., Runtenfranz J.
Stress and strain of letter sorting in an air mail head office
Belastung und Beanspruchung bei der Briefverteilung in einer Luftpostleitstelle [en alemán]
Mail sorting requires rapid and accurate information processing. This was revealed by a job study of female postal employees in Germany. Questionnaires, time-and-motion study and physiological measurements were used. Heart rate, oral temperature and musculoskeletal complaints were slightly higher during night shifts than during day shifts. No differences existed in the excretion of the catecholamines (adrenaline and noradrenaline) between day and night shifts. Higher amounts of mail did not affect any of these physiological parameters.
Arbeitsmedizin - Sozialmedizin - Präventivmedizin, 1990, Vol.25, No.5, p.202-204. 213-219. Illus. 16 ref.
Itani T., Otani T., Takahara M., Takeuchi K., Ono H., Miura M., Koda S., Aoyama H.
A study on operating time and workload in different types of visual display terminal work
VDT sagyō-jikan bunpu to sagyō-futan ni kansuru kenkyū [en japonés]
Visual display terminal (VDT) operating time was recorded automatically, and a questionnaire study concerning the working conditions and health of the operators was carried out in different sections of an electronics company: purchasing and selling, drawing, and production administration. The operating time varied among the different types of VDT work and also among the operators of a given section. The operating time estimated by the operators in their questionnaire replies was slightly longer than that shown by the recorded data; however, the distribution patterns of operating time established by the 2 methods were very similar. The operators of the purchasing and selling section and the drawing section complained of problems with respect to their workload. The operators of these 2 sections complained of related health problems more frequently than the operators of the product administration section. This suggests that it is important to estimate the VDT operating time in individual jobs, as it can be a crucial factor in preventing occupational health hazards related to VDT work.
Journal of Science of Labour - Rōdō Kagaku, June 1989, Vol.65, No.6, p.356-364. Illus. 13 ref.
Recognition of cerebrovascular stroke resulting from employment
Nōkekkan-shōgai no gyōmujō gai [en japonés]
In recent years, the actions for legal compensation in cases of cerebrovascular disease incurred in relation to employment have been increasing. In Oct. 1987, the Japanese Ministry of Labour repealed the old standards and enacted new standards for the recognition of cerebrovascular and cardiac diseases resulting form employment. The new standards are characterised by an emphasis on the concept of overwork, and the range of time of subjection to an excessive workload has been extended exceptionally to a week before the onset of disease. Not only the volume of work but also the nature of the job and the working environment are to be considered. In other words, excessive workload is evaluated with more flexibility than in the past. Furthermore, continuous psychological load has been additionally taken into consideration in the new standards. The effect of the new standards is illustrated by some case reports.
Japanese Journal of Traumatology and Occupational Medicine, May 1989, Vol.37, No.5, p.311-317. 8 ref.
Ikeda M., Sato K., Tamura T.
Comparative study of the workload of slow and express train drivers
Tokkyu ressha to futsu-ressha no untensagyō futan no hikaku [en japonés]
The results obtained indicate that the workload of drivers of slow trains is optimum because their mean critical flicker fusion frequency (CFF) values and heart rate variations are a little higher than normal when driving but drop to the normal level during a relatively long stop at a station. As for express train drivers, their CFF values indicate that their psycho-physiological conditions tends to fall into a monotonous state, while their heart rate variations remain more or less the same as in the case of drivers of slow trains.
Railway Technical Research Institute Report, Mar. 1989, Vol.3, No.3, p.27-32. Illus. 9 ref.
Noise of medium intensity - effects on office and administrative tasks
Geräusche mittlerer Intensität - Auswirkungen auf Büro- und Verwaltungstätigkeiten [en alemán]
Conclusions to be drawn from the results of field and laboratory studies on the effects of noise levels between 30 and 80dB(A) on mental tasks are: tasks requiring intensive concentration, numerical ability and logical thinking are impaired at noise levels of 50dB(A) and higher; decision time is prolonged; work progress is slowed down; error rate increases; performance of short-time memory decreases.
Zeitschrift für Lärmbekämpfung, 1989, Vol.36, No.1, p.2-7. Illus. 23 ref.
Takemoto A., Yoshinori H.
A study on the effects of VDT work on information processing ability
VDT-sagyō no jōhō shori nōryoku e no eikyō ni kansuru kenkyū [en japonés]
Fourteen male college students aged 22-23 were tested for visual performance and information processing ability after working with VDTs for 5, 10, 15, or 30 minutes. Before and after each working period, each subject was given a visual flicker fusion test and asked to write down a sequence of random numbers. From the quality of the random number sequence reproduced, the information processing ability was calculated according to a mathematical model. With respect to initial values, information processing ability increased up to 15 minutes of work but was diminished after working for 30 minutes. The vision flicker fusion test gave identical results. Thus, VDT work influences not only visual ability but also the information processing ability of the brain.
Japanese Journal of Ergonomics - Ningen Kogaku, Oct. 1988, Vol.24, No.5, p.313-318. Illus. 14 ref.
Kahabka G., Rohmert W.
Physiological measurement strategy for mixed psychological/physical work. Example: driving a commercial vehicle
Physiologische Messtrategie bei psychophysischer Mischarbeit. Exemplarische Analyse: Führen eines Nutzfahrzeuges [en alemán]
Assessment of the psychophysical stress involved in driving a commercial vehicle comprises simulation of the task on the computer and performing it in reality on a motorway, a country road and an urban street. During driving under laboratory and field conditions a series of physiological parameters (e.g. vital capacity, tremor, breathing rate) are measured. In addition, questions concerning subjective well-being are answered and multiplication tasks are performed.
Zentralblatt für Arbeitsmedizin, Arbeitsschutz, Prophylaxe und Ergonomie, 1988, Vol.38, No.9, p.262-273. Illus. 33 ref.
Komatsubara A., Yokomizo Y.
On the ergonomic limits of computer system response time
Keisanki ōtō jikan no ningen kōgakuteki kyoyō han'i ni kansuru ichi kōsatsu [en japonés]
From the viewpoint of mental workload, the psychologically acceptable lower and upper limits of computer system response time (SRT) in interactive computer tasks were experimentally studied. SRTs longer than about 6sec give high irritation, and SRTs shorter than about 1s give a feeling of being rushed and result in low performance. The results validate the upper limits of response time observed by others, and show that lower limits exist as well.
Japanese Journal of Ergonomics - Ningen Kogaku, June 1988, Vol.24, No.3, p.195-202. 15 ref.
Seibt A., Friedrichsen G., Geist H.W., Schurig H.U., Roehner J.
Studies on the stress caused by shift work and automated manufacturing
Untersuchungen zur Beanspruchung durch Schichtarbeit unter den Bedingungen automatisierter Fertigung [en alemán]
Shift work is an unspecific stress factor, the effect of which is modified by specific workplace conditions and tasks. To identify a potentially increased health risk due to flexible hours of work including prolonged shifts, a group of ten test persons in the metal-processing industry was checked during 8-hour and 12-hour shifts. The measured values of selected physical and psychological variables and data on general well-being indicate that work of the type discussed does not entail an increased health risk. Furthermore, the resulting longer rest periods improve the effects of recreation. From the viewpoint of hygiene at work, however, a workplace-related analysis of the physical and mental workload is required.
Zeitschrift für die gesamte Hygiene und ihre Grenzgebiete, July 1988, Vol.34, No.7, p.409-412. Illus.
Hancock P.A., Meshkati N.
Human mental workload
A survey of recent developments in the assessment of mental workload. Examined are the current methodologies, individual differences, unanswered questions, and future directions for the mental workload issue. Contents: properties of workload assessment techniques; physiological measures; heart rate variability; effort and fatigue in relation to the workload experienced during normal daily routines; subjective assessment techniques; cognitive psychology of subjective workload. A preliminary proposal for a cohesive model of mental load is presented.
Elsevier Science Publishers B.V., P.O. Box 1991, 1000 BZ Amsterdam, Netherlands (for the USA and Canada: Elsevier Science Publishing Company, 52 Vanderbilt Avenue, New York, NY 11017, USA), 1988. 382p. Illus. Bibl. Price: USD 100.00; NLG 190.00.
Workload evaluation scales for train drivers
Dōryokusha jōmuin no 'wāku rōdo hyōka sukeru' no kaihatsu [en japonés]
Scales for evaluating train drivers' workload with off-duty hours taken into account were developed. The scales are based on Ohshima's Tables of Workload and of Sleep Effect as well as weighted by empirically estimated effects of duty types and rest conditions. Of the two sub-scales, one measuring fatigue effects and the other rest effects, the former showed high correlation with subjective ratings. Examining the validity of the latter and integrating the two sub-scales remain for further studies.
RTRI Report, Mar. 1988, Vol.2, No.3, p.17-24. Illus. 5 ref.
Ikeda M., Satō K., Oshima M.
Physiological workload of train drivers on a suburban commuter railway
Toshikinkō tsūkinsen densha untenshi no seirigakuteki-futando ni kansuru chōsa [en japonés]
A study of the difference in physiological workload between two groups of motormen (drivers of electric trains). The first group consisted of those engaging in daytime duties (7:00-15:00) and the other of those on duty from 18:00 to 13:00 of the next day, including 5 hours sleep in the middle of the night. Critical flicker fusion frequency values for the second group were lower than those for the first and brain activity levels for the second group were also slightly lower than those for the first. Nevertheless, the physiological condition of those in the second group returned to their standard levels after working hours. Therefore, fluctuations in these values were within the permissible range.
RTRI Report, Mar. 1988, Vol.2, No.3, p.13-16. Illus. 6 ref.
Sex differences in mental workload during performance of mental tasks
In 1 of 2 experiments which had been previously carried out in male students, 24 female students performed 4 mental tasks for 5min each. An objective electroencephalographic mental workload index, i.e. occipital midline beta-2 (Ozβ2) amplitude, showed that all tasks caused a higher mental workload in females than in males. A subjective mental workload index, i.e. subjective rating of task difficulty (SRTD) however showed that females had a tendency to perceive a lower mental workload than did males. In the 2nd experiment, where a paced calculating task was imposed on another 24 female students at 5 grades of task load for 5min each, the critical values for excessive workload were estimated to be about 7.0µV (the difference between the levels at work and at rest) for Ozβ2 amplitude and 3.5 for SRTD. Hence none of the above 4 tasks constituted an objectively excessive workload in females, whereas all of them were excessive in males.
Industrial Health, 1987, Vol.25, No.4, p.183-193. Illus. 18 ref.
Working conditions and heart attack
Arbeitsbedingungen und der Herzinfarkt [en alemán]
Myocardial infarction is the result of a combination of several factors. Type A behaviour (marked by, e.g. a defensive attitude and avoidance of conflict situations) plus pressure at work (e.g., demand for high quality, non-routine work within short time periods) lead to chronic, self-induced overworking and consequently to irreversible health impairment. Performance drops due to the weaker physical state. A sudden high workload may trigger myocardial infarction.
Humane Produktion - Humane Arbeitsplätze, Dec. 1987, Vol.9, No.10, p.16-18. 1 ref.
Umemura M., Aizawa N
Influence of noise on mental work
Sōon ga seishin sagyō ni ataeru eikyō ni tsuite [en japonés]
Subjects performed 3 tasks while being subjected to noise. The tasks were: addition or subtraction of 120 pairs of 2-digit numbers; inspection of a page of numbers and marking those that met certain criteria; inspection of a page of Japanese syllabic characters and erasure of 4 specified characters. Error rates and completion times increased with increasing sound pressure level (from background to 90dBA) for the arithmetic operations and evaluation of numbers, but not in the case of character recognition. This may be due to involvement of the sense of hearing in the first 2 tasks.
Japanese Journal of Ergonomics - Ningen Kogaku, 1986, Vol.22, No.5, p.259-268. Illus. 10 ref.
Misawa T., Shigeta S.
An experimental study of work load on VDT performance - Part 2. Effects of difference in input devices
VDT sagyō ni okeru sagyō futan ni kansuru jikkenteki kenkyű. Dai-2-hen. Nyűryoku hōshiki no sōi ni yoru eikyō [en japonés]
The subjects of the experiment were 8 healthy male college students. In an experimental word processing task, the subjects searched for e's in given sequences of letters displayed on the CRT and converted them to 5's by input device operations (keyboard or lightpen). Critical flicker fusion frequency (CFF), near point distance, accommodation time, subjective fatigue symptoms, blinking counts, pupillary reflex, electromyogram in upper limb, neck and shoulder and performance score were measured. Decrease in CFF was observed under both experimental conditions. Increments in complaints of subjective fatigue related to visual function were seen in both cases. A higher error rate was observed with use of the lightpen than with the keyboard. The frequencies of blinking and pupil-size changes were lower in the subjects using the lightpen. This suggests that the time spent looking at the VDT screen is longer with the lightpen. More complaints of subjective fatigue in the upper body, and also greater electromyogram amplitudes in upper limb, neck and shoulder muscles were observed in the subjects using the lightpen. This suggests that the muscular load on the upper limbs and the restriction of posture is greater in the case of the lightpen.
Japanese Journal of Industrial Health - Sangyō-Igaku, Nov. 1986, Vol.28, No.6, p.462-469. Illus. 24 ref.
Misawa T., Shigeta S.
An experimental study of work load on VDT performance - Part 1. Effects of polarity of screen and colour of display
VDT sagyō ni okeru sagyō futan ni kansuru jikkenteki kenkyū. Dai-1-hen. VDT gamen no hyōji-kyokusei to hyōji-shoku no eikyō [en japonés]
Eight healthy male college students searched for e's in given sequences of letters displayed on a CRT and converted them to 5's by keyboard operations. Four levels of screen image (positive and negative screens and green and white coloured displays) were adopted and 2h were given for each operation. Critical flicker fusion frequencies (CFF), near point distance, accommodation time, subjective fatigue symptoms, heart rate, electromyogram in upper limbs and performance score were measured. Decrease in CFF, extension of near point distance and increase in complaints of subjective fatigue related to visual function were observed under all experimental conditions. Greater extension of near point distance and more complaints of subjective fatigue were observed in subjects using the green display than in those using the white display. This suggests that the visual load using the green display is larger than that using the white display. A larger decrease in CRT and greater complaints of subjective fatigue occurred with negative screens than with positive screens. This suggests that the visual load using the negative screen is larger than that using the positive screen.
Japanese Journal of Industrial Health - Sangyō-Igaku, Nov. 1986, Vol.28, No.6, p.420-427. Illus. 27 ref.
Assessment of psychic stress factors at work
Bedömning av psykiska belastningsfaktorer i arbetet [en sueco]
The screening method developed by specialists in Finland to assess the psychic stress of work in association with monitoring of the work environment is presented. The method is based on the results of studies on stress in working life and on job description methods. It is intended for occupational health personnel. The method covers factors like underload-overload, work organisation, job content, social factors including human relations. A sample checklist is enclosed.
Institute of Occupational Health, Publication Office, Topeliuksenkatu 40 a A, 00250 Helsinki, Finland, 1986. 40p. Illus. 15 ref. Price: Fm.9.00.
Sharma V.M., Sridharan K., Pichan G., Panwar M.R.
Influence of heat-stress induced dehydration on mental functions
The effect of primary dehydration of various levels (1, 2 and 3% body-weight deficits) on mental functions of different complexities were studied in 8 heat acclimatised subjects drawn from tropical regions of India. These subjects were also studied after a bout of exercise in hot-dry and hot-humid conditions at 34°WBGT. No statistically significant change in routine mental work was seen either under dehydration, per se, of any level or after subsequent exercise under heat, when compared with the normal state. Significant decreases in concentration and co-ordination were observed at the 2 and 3% dehydration levels.
Ergonomics, June 1986, Vol.29, No.6, p.791-799. 24 ref.
Fibiger W., Christensen F., Singer G., Kaufman H.
Mental and physical components of sawmill operatives' workload
The mental and physical components of the workload for 6 categories of hardwood sawmill workers were investigated using urinary cortisol and catecholamine, oxygen consumption and self-assessed level of workload. Adrenaline concentration in urine was significantly higher for sawyers than for others with higher energy output. The sawyers also had a significant lower ratio of noradrenaline to adrenaline. Both adrenaline and the ratio correlated with self-assessed mental effort, whereas noradrenaline and dopamine correlated with self-assessed physical effort. The circadian pattern of cortisol excretion was similar in all categories of workers. The results indicate that catecholamines in urine are useful for evaluating the mental component of an individual's work.
Ergonomics, Mar. 1986, Vol.29, No.3, p.363-375. Bibl.
Sautkin V.S., Šaptala A.A., Brjuhanova S.T.
State of the cardiovascular system in operators of the telephone information service during work
Sostojanie serdečno-sosudistoj sistemy telefonistok spravočno-informacionnoj služby v processe truda [en ruso]
Heart rate, blood pressure, minute volume and electrocardiogram were recorded at intervals during a 6.5hr daytime shift for 58 female telephone telephone operators in the information services of 2 cities. Heart rate, blood pressure and minute volume all increased over the shift, systolic and pulse pressure became more variable, and the shape of the electrocardiogram changed. Apparently the heart, and not the blood vessels, responds to the stress of the job; this produces a desynchronisation of cardiac and vasomotor regulation of the circulatory system. Because the stress is due to the combination of heavy information input and limited physical mobility, it is recommended that the work of telephone operators be broken up by workbreaks with active and passive means of relaxation.
Gigiena truda i professional'nye zabolevanija, Jan. 1985, No.1, p.11-14. Illus. 6 ref.
Hancock P.A., Meshkati N., Robertson M.M.
Physiological reflections of mental workload
Review of studies reporting physiological responses to mental workload. 13 measures are evaluated from the viewpoints of practical application and relevance to actual central nervous system (CNS) activity. Heart rate measurement is the most practical of the measures, while event-related potentials (fluctuations in the endogenous activity of the nervous system) in response to environmental stimulation are the best measures of CNS activity. Changes in auditory canal temperature are suggested as the ideal composite measures of mental workload.
Aviation, Space, and Environmental Medicine, Nov. 1985, Vol.56, No.11, p.1110-1114. Illus. 33 ref.
Mental workload, psychosocial stress and fatigue. The role of computers
La charge pyschique, le stress psychosocial et la fatigue. Le rôle de l'informatique [en francés]
Review of recently published literature on fatigue, stress and mental health - the emphasis is on the relationship between psychosocial stress and new technologies such as those using computers. A global approach to these concepts leads to a more encompassing ergonomic analysis of working conditions. The usefulness of epidemiologic methods in the prevention of psychosocial stress is demonstrated.
Cahiers de notes documentaires - Sécurité et hygične du travail, 3rd quarter 1985, No.120, Note No.1538-120-85, p.325-330. 42 ref.
Piikivi L., Hänninen H., Martelin T., Mantere P.
Psychological performance and long-term exposure to mercury vapors
The psychological test performances of a group of 36 male chlorine-alkali workers were compared with the level of exposure to mercury (Hg) and to the results obtained from a referent group. Hg exposure had lasted for ≥10 years and had been monitored by regular health examinations and urine analyses. The more heavily exposed workers performed more poorly on the verbal intelligence test than the referents. Impairments in the memory tests showed a statistically significant correlation with the actual exposure level, especially with the concentration of Hg in blood. The level of Hg in the air was calculated from the dose indicators. The results support the recommended exposure limit of 25µg/m3 for Hg vapour in workplace air.
Scandinavian Journal of Work, Environment and Health, Feb. 1984, Vol.10, No.1, p.35-41. 19 ref.
Stress and psychopathology of work
Stress et psychopathologie du travail [en francés]
An attempt at clarifying the meaning of the word "stress". Occupational stress factors (physical, psycho-social and socio-economic) and their pathological manifestations are surveyed through the professional literature. The effects of stress can be reduced by improving work situations, tools and environments, but it is especially important to consider the social organisation of work by examining the needs and motivations of man.
Cahiers de notes documentaires - Sécurité et hygične du travail, 3rd quarter 1984, No.116, Note No.1493-116-84, p.353-362. 42 ref.
Šlejfman F.M., Zaharenko M.I., Laščuk A.A.
Bases for microclimatic standards for industrial installations, taking into account the level of intensity of operators' tasks
Obosnovanie norm mikroklimata proizvodstvennyh pomeščenij s učetom kategorii naprjažennosti operatorskogo truda [en ruso]
Laboratory experiments with a simulated control panel showed that the thermal state of persons engaged in mental work is determined by the intensity of the work. It is thus appropriate to set microclimatic standards on the basis of the intensity as well as the physical or mental difficulty of the work. Criteria for such standards are defined, and optimal and permissible air temperatures are proposed for mental work of levels I-III (as defined by the All-Union Scientific Research Institute for Occupational Health and Safety and the USSR Academy of Medical Sciences in 1972).
Gigiena i sanitarija, July 1983, No.7, p.9-11. 22 ref.
Klotzbücher E., Fichtel K., Miericke H., Hamdorf G.
The effect of two lamps with the same colour temperature, but with different spectra, on mental performance and on certain physiological functions
Über den Einfluss zweier Lampen mit gleicher Farbtemperatur, aber verschiedener spektraler Zusammensetzung auf Leistung bei geistiger Arbeit und ausgewählte physiologische Funktionen [en alemán]
The experiments lasted 1.5h each and involved problem solving in rooms with illuminance levels of 400lx produced either by an incandescent light source (tungsten-halogen lamp) or by a fluorescent source (metal halide lamp), both at a colour temperature of 3,200°K. There was no difference in performance between the two groups, but there was a significant increase in symptoms of physiological stress among subjects exposed to the fluorescent light source. Colour temperatures alone cannot be used as criterion for evaluating the effects of the lamps.
Zeitschrift für die gesamte Hygiene und ihre Grenzgebiete, 1983, Vol.29, No.8, p.467-472. Illus. 21 ref.
Gaussin J., Van Laethem A.
The ergonomics of mental activity
L'ergonomie des activités mentales [en francés]
Proceedings of the 17th Congress of the Francophone Ergonomics Society (Louvain-la-Neuve, Belgium, Sep. 1981) on the ergonomics of mental activity in various professional activities (highly automated production, manufacture and processing of products, services). Contents include: methods of studying working conditions associated with new technologies (study of cognitive processes and psycholinguistics); presentation of immediate and concrete results of ergonomic improvements in enterprises; summary of principal remaining problems and of the positions of the participants in technological change.
Cabay-Jezierski éditeur, Agora 11, 1348 Louvain-la-Neuve, Belgium, 1982. 113p. Illus.
Subjective mental workload
Subjective workload is of increasing importance in user-machine systems, as the human operator is required to monitor complex systems. The relation between physical, cognitive, manual-control, and time stress tasks and the subjective load experienced by an operator is discussed. Models of subjective mental workload should allow for the 4 parameters physical exertion, rate of information processing, memory load and subjective performance criterion (acceptable error rate).
Human Factors, Feb. 1982, Vol.24, No.1, p.25-40. Illus. 50 ref.
Workload in underground miners
Die Beanspruchung des Bergmannes im Untertagebetrieb [en alemán]
Increasing mechanisation of coal getting has resulted in a reduction of heavy physical work and an increase in vigilance and concentration tasks. Psychophysiological workload is studied and recent occupational medicine findings are reviewed. Sections cover: total mechanisation (man-machine system, actual working time, work breaks and auxiliary tasks); workface microclimate (high temperatures, low temperatures, ventilation); sensory stress (dust, gases, smells, noise, communication, lighting); assessment of workload in various jobs (coal plough operator or supervisor, roof shield operator, shift foreman, sectional face cutter, monorail driver and supervisor); adaptation to difficult coal-getting conditions; uncomfortable working postures; professional experience; exceptional mental and emotional stress factors.
Bergbau, 1981, No.2, p.88-91, No.3, p.137-141, No.4, p.195 and No.6, p.422-432.
National Conservatory of Arts and Sciences, Laboratory of occupational physiology and ergonomics (Conservatoire national des arts et métiers, laboratoire de physiologie du travail et d'ergonomie)
Physical and mental workload
Charge physique et charge mentale [en francés]
Guide designed to help in training workers in the analysis of their working conditions. Part 1 deals with work posture: work factors that lead to bad postures; physiological cost of a given posture. Part 2 deals with physical work (heat and cold): muscular activity; regulation of body temperature; protection against high and low temperatures. Part 3 analyses mental activity at work (work tempo, learning of work procedures, working instructions; relationships with the world outside the plant, man-machine system, mental fatigue, etc.).
Agence nationale pour l'amélioration des conditions de travail, 16-20 rue Barbčs, 92120 Montrouge, France, 1981. 56p.
National Conservatory of Arts and Sciences, Laboratory of occupational physiology and ergonomics (Conservatoire national des arts et métiers, laboratoire de physiologie du travail et d'ergonomie)
Introduction to work analysis on the shop floor
Introduction ŕ l'analyse du travail en atelier [en francés]
Presents methodology for analysing certain aspects of working conditions as a basis for training workers in the analysis of their working environment. Sections deal with: definition of workload; components of workload (characteristics of work, conditions under which work is done, worker's physiological and psychological status); assessment of workload and the consequences for the workers; presentation of various methods of work assessment; description of ergonomic analysis; distinction between an analysis carried out by a specialist and an analysis by a trade union representative and his co-workers.
Agence nationale pour l'amélioration des conditions du travail, 16-20 rue Barbčs, 92120 Montrouge, France, 1981. 40p. 37 ref.
Mamelle N., Munoz F., Collin D., Charvet F., Lazar P.
Quantifying female workload during pregnancy
Quantification de la charge de travail féminin pendant la grossesse [en francés]
Presentation of a method for quantifying fatigue of various origins in pregnant women. The report is based on the results of a questionnaire survey of all women giving birth in maternity clinics; this prospective obstetric study and a retrospective study of working and familial conditions covers 3500 computer-processed case records between 1977 and 1978. The main fatigue factors were found to be: the home, family work load, transportation, type of work, type of job (posture, physical and mental stress, work on machines), environment (lighting, heat, noise), possible changes in working conditions and work stoppages.
Archives des maladies professionnelles, 1982, Vol.42, No.4, p.205-210.
Heat stress impairment of mental performance: A revision of tolerance limits.
A reevaluation of the results of early studies and an analysis of recent data suggest a mental performance impairment/heat stress relationship closely related to human thermophysiological tolerance limits. Pilots were tested on 2 mental tasks involving number, addition and numerical comparison at 3 effective temperatures 38.1, 42.8 and 45.6°C. Exposure scores were subtracted from preexposure control scores determined at a comfortable temperature. The diffrence, expressed as a function of the physiological tolerance of each subject, was used to calculate improvement or decrement in performance. This analysis also indicates that the present NIOSH standard for sedentary work performance in heat contains a safety margin at each time exposure wherein increased temperature may be tolerated without statistical impairment of performance.
Aviation, Space, and Environmental Medicine, Mar. 1981, Vol.52, No.3, p.177-180. Illus. 20 ref.
Klotzbücher E., Fichtel K., Miericke H., Hamdorf G.
Influence of lighting sources of different spectral composition on ability to perform mental tasks, and on selected physiological functions
Einfluss von Beleuchtungsquellen unterschiedlicher spektraler Zusammensetzung auf Leistung bei geistiger Arbeit und ausgewählte physiologische Funktionen [en alemán]
Literature survey on the effects of the spectral composition of light; description of arithmetic performance test methods and results of these tests in lighting conditions from 3 different types of source (fluorescent, halide, high-pressure sodium vapour: performance criteria (time taken for arithmetic tests, percentage of correct solutions), physiological reactions (heart rate, respiratory indices), work rhythm and pulse rate depending on type of light source. The best results are obtained with sodium-vapour lighting. It is probable that this type of lighting (which contains a higher proportion of long waves) stimulates the performers' activity more than the other types of lighting.
Zentralblatt für Arbeitsmedizin, Arbeitsschutz, Prophylaxe und Ergonomie, July 1980, Vol.30, No.7, p.241-248. Illus. 26 ref.
Requirements of night work in hospitals as factors in workload
Les exigences du travail hospitalier de nuit comme facteurs de la charge de travail. [en francés]
A study of the effects of night work should take account not only of all aspects of the shift system followed, but also of the specific requirements of the work performed. Up to the present, very few studies have been devoted to the last-mentioned factors. This article attempts to highlight their importance by presenting a method of analysis adapted to night shift-work situations in hospitals. 5 types of requirements are listed: work intensity, physical requirements, mental requirements, social significance of the tasks, requirements linked to the social environment. These requirements vary from one hospital service or department to another, according to the socio-technical requirements of each. For each category of requirement, indicators are proposed and hypotheses put forward regarding their possible consequences on the life of the personnel concerned outside their working hours.
Travail humain, 1980, Vol.43, No.1, p.17-31. 16 ref.
Seppälä P., Louhevaara V., Siikaranta R., Oja P.
Effect of the production process on mental and physical work demands and stress in the sawmill industry
Tuotantotekniikan vaikutus työn psyykkiseen ja fyysiseen kuormittavuuteen sahateollisuudessa [en finlandés]
Information was collected from 22 sawmills (195 jobs in 3 levels of mechanisation and automation; 340 workers covered). Variables in job characteristics and working conditions studied: mental functions, knowledge and experience demanded, variety or monotony of work, social contacts, quantity and quality of physical stress, physical (noise, temperature, humidity) and chemical environmental factors, and work schedule. Data were collected on production process and task analysis, energy expenditure, oxygen consumption and heart rate, sick leave, technology and work organisation (negative, short-cycled tasks; keen concentration; economically important, perceptual and decision-making tasks at a paced tempo). An increase in the level of mechanisation and automation only slightly changes the nature of sawmill jobs, but total work structure can be significantly changed by means of reorganisation (e.g. job rotation to increase the variety of the work profile).
Tutkimuksia 159/1979, Työterveyslaitos, Laajaniityntie 1, 01620 Vantaa 62, Finland, 1979. 236p. Illus. 35 ref. Price: Fmk.45.00.
Schiele R., Gossler K., Schaller K.H.
Studies on behaviour of stress-related biological parameters and defined physical and mental loads
Untersuchungen zum Verhalten verschiedener beanspruchungsbezogener biologischer Parameter unter definierten physischen und psychischen Belastungen [en alemán]
Scientific methods do not yet permit satisfactory analysis of the causes and pathological effects of major physical or mental loads. This research report studies the validity of the biochemical parameters used as indices of the load. Stress and strain are defined, and results are presented of observations in subjects following physical effort or mental stress. The degree to which the parameters provide an objective measurement and a differentiation of physical and mental stresses is examined. An appendix describes in detail the analytical methods used and their reliability criteria, their applications, and the normal limits derived from them.
Forschungsbericht Nr. 185, Bundesanstalt für Arbeitsschutz und Unfallforschung, Postfach 17 02 02, 4600 Dortmund 17, Germany (Fed.Rep.), 1978. 169p. Illus. 57 ref. Price: DM.19.00.
Klotzbücher E., Fichtel K.
The effect of noise on mental performance and selected physiological functions in different combinations of noise and dynamic muscular work
Der Einfluss des Lärms auf Leistung bei geistiger Arbeit und ausgewählte physiologische Funktionen bei unterschiedlichen Kombinationen zwischen Lärm und dynamischer Muskelarbeit [en alemán]
Arithmetic tasks were performed in combination with work on a bicycle ergonometer and white noise. The best performance was obtained: with no work + noise of 70 or 85dB(AI); work at 15W + noise of 55 or 70dB(AI); work at 30W + noise of 55dB(AI). Physiological reactions taken into account were cardiac cycle duration, respiratory cycle duration, cardiac rate, respiratory rate, and epinephrin and norepinephrin excretion. In concentrated mental work noise should not exceed 55dB(AI); for moderate mental concentration it should be 70-85dB(AI) without muscular exertion, 55-70dB(AI) with light exertion, and 55dB(AI) with moderate exertion.
International Archives of Occupational and Environmental Health, 1978, Vol.41, No.4, p.237-251. Illus. 16 ref.
Leplat J., Welford A.T., Bainbridge L., Hacker W., Plath H.E., Richter P., Zimmer K., Sperandio J.C., Teiger C., Borg G., Brown I.D., Wildervanck C., Mulder G., Michon J.A., Yoshitake H.
Symposium on mental work load.
Symposium sur la charge de travail mental. [en francés]
Proceedings of a symposium held in Paris on 25 July 1976, published in English and French in the 2 journals, respectively. Papers presented: factors determining workload; mental workload as a function of demand, capacity, strategy and skill; forgotten alternatives in skill and workload; internal representation of task structure and mental load of work; regulation of working methods as a function of workload in air traffic controllers; regulation of activity as a tool for studying workload in perceptual motor tasks; subjective aspects of physical and mental load; dual task methods; mental load in car driving; characteristic patterns of subjective fatigue symptoms.
Ergonomics, Mar. 1978, Vol.21, No.3, p.141-233. Illus. 167 ref.; Travail humain, Vol.40, No.2, p.193-304. Illus. 167 ref.
Mental activity changes in subjects with chronic manganese poisoning
Osobennosti intellektual'noj dejatel'nosti u bol'nyh s hroničeskoj intoksikaciej margancem [en ruso]
Results of psychological tests (Wechsler) in 130 arc welders with different degrees of manganese poisoning are reported. Concentration and short-term memory began to be affected at the subclinical stage of the condition, when there were also signs of disturbance of visual-motor performance and co-ordination of movements. Disturbances of abstract and logical thought occurred only at an advanced stage of manganese poisoning. Calculation and deciphering tests are recommended for early diagnosis.
Gigiena truda i professional'nye zabolevanija, Mar. 1978, No.3, p.23-26. 9 ref.
Methods of evaluation of the mental load
Les méthodes d'approche de la charge mentale. [en francés]
General remarks on the work load (different points of view of the work organiser and the ergonomist) and the mental load (qualitative and quantitive assessment), subjective experience of mental load (individual and collective reactions, fatigue). The article is mainly devoted to a review of objective evaluation criteria (work studies especially on the basis of the bit as unit of information, study of the operator's attitude in a mental work situation; productivity studies). The part played by environmental factors, trends in the mental load and ageing is also assessed. Example of questionnaire design.
Cahiers de médecine interprofessionnelle, 1st quarter 1977, No.65, p.19-38. Illus. 2 ref.
Heat and human work without great muscular effort: III. Explanatory models of the specific effects of heat stress on psychomotor and mental performance (laboratory tests)
Chaleur et travail humain sans composante musculaire importante: III. Modčles explicatifs des effets spécifiques de la contrainte thermique chaude sur la performance psychomotrice et mentale (études de laboratoire). [en francés]
Publications reviewed in this article show relations to exist between various indices of performance and indices of the thermal status (rectal or oral temperature), circulatory activity (heart rate) and sweating (weight changes). A number of hypotheses aiming at explaining and predicting the specific effects of heat on psychomotor performance are examined. These hypotheses, which are generally based on knowledge of the physiological manifestations of higher nervous processes, apply either only to the intensive dimension of behaviour responsible for the performances achieved, or to the directional dimension of this behaviour.
Travail humain, 1976, Vol.39, No.2, p.311-327. Illus. 47 ref.
Study of workloads of supermarket cash register operators
Etude des charges de travail chez les caissičres de libres-services. [en francés]
This communication to the 13th National Symposium on Occupational Medicine (Tours, France, 2-5 Oct. 1974) studies the following aspects of cash-register operators' work: working hours; organisation; duties (restocking shelves; checking-out purchases); workpost description; job description; physical workload (posture, movements); mental strain; emotional strain; environmental stress. Unable to use heart rate measurement techniques or ECG recordings to evaluate workload, the author used 4 different data: duration of apprenticeship, fatigue, errors, absenteeism and staff turnover. Apprenticeship is relatively long; nervous fatigue certainly exists, but does not give rise to much absenteeism; errors are relatively infrequent. Favourable factors: generally short commuting distances; flexible hours; varied work; job satisfaction and relative prestige.
Archives des maladies professionnelles, Jan.-Feb. 1976, Vol.37, No.1-2, p.112-121.
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