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PubMed1990

Eye movement indices of mental workload.

Four investigations were carried out to assess the feasibility of using eye movement measures as indices of mental workload. In the first experiment, saccadic extent was measured during free viewing while subjects performed low, moderate and high complexity, auditory tone counting as the workload tasks. The range of saccadic extent decreased significantly as tone counting complexity (workload) was increased. In the second experiment the range of spontaneous saccades was measured under three levels of counting complexity with a visual task that did not require fixation or tracking. The results indicated that the extent of saccadic eye movements was significantly restricted as counting complexity increased. In the third experiment, the effects of practice were examined and decreased saccadic range under high tone counting complexity was observed even when significant increases in performance occurred with practice. Finally, in experiment 4, the first experiment was repeated with additional optokinetic stimulation and the saccadic range was again observed to decrease with tone counting complexity. The results indicated that the extent of spontaneous and elicited eye movements was significantly restricted as counting complexity increased. We conclude that this measure may provide a valuable index of mental workload.

Adult↗

PubMedDate not supplied

Intracerebral event-related potentials during memory workload.

The goals of this research were to use an original Memory Workload Paradigm with visually presented words and to explore the following points: (1) With depth electrodes, stereotaxically implanted in intracerebral structures bilaterally (amygdala, anterior hippocampus, posterior hippocampus, orbital-frontal, anterior cingulate gyrus and cortical areas) to delineate brain structures involved in this memory workload task. (2) To investigate whether a memory load effect can be demonstrated on the latencies and amplitudes of the late components of intracerebral event-related potentials (ERPs). (3) If a load effect is present, do intracerebral ERP latencies and amplitudes vary as a function of memory set size? The analysis of intracerebral ERPs revealed that a negative waveform with a maximum amplitude around 400 ms was the component which was significantly involved in memory workload tasks. Significant load effects for the N4 latency were found in both amygdalae and the left posterior hippocampus, as well as both anterior regions of the second temporal gyri (p < 0.01). The intracerebral N4 latency varied linearly as a function of set size while the amplitude varied quadratically for the right amygdala and the left posterior hippocampus (p < 0.05). The results support the conclusion that the Memory Workload Paradigm provides the possibility to use memory load effect on ERPs as a marker to identify which intracerebral structures are predominantly involved in memory functions.

Adult↗

PubMed1991

Workload and job satisfaction among general practitioners: a review of the literature.

The workload of general practitioners (GPs) is an important issue in health care systems with capitation payment for GPs services. This article reviews the literature on determinants and consequences of workload and job satisfaction of GPs. Determinants of workload are located on the demand side (list size and composition of the patient population) and the supply side (organization of the practice and personal characteristics of the GP). The effects of workload and job satisfaction on workstyle and quality of work have been reviewed. The length of consultations or booking intervals seems to be an important restriction for workstyle and quality of work.

Job Satisfaction↗

PubMed1995

Effects of attention and time-pressure on P300 subcomponents and implications for mental workload research.

Our approach to objective measures of mental workload is establishing relationships between components of the event-related brain potential (ERP) and information processing stages. These relationships can be used to infer the influence of specific workload conditions on specific processing stages. We recently showed that the ERP component P300 in choice tasks is composed of two subcomponents, P-SR and P-CR, which are time-related to stimulus-evaluation and response-selection. With these relations we could specify which processing stages were affected when certain workload conditions are varied. When attention was divided between the visual and auditory modalities compared to (unimodal) focused attention, the choice reaction time (RT) was prolonged, primarily in the auditory modality. This delay was mainly reflected in the P-CR latency, which shows that the division of attention mainly impairs the response-selection process in the auditory modality due to a bias of attention towards the visual modality. When the time-pressure was increased, the latency of the P-CR (and not of the P-SR) was shortened, but less than the choice RT. This suggests a (limited) acceleration of response-selection but not of stimulus evaluation. Since the response-selection process was accelerated less than the overt choice RT, an increase of the error rate was consequently observed. In summary we showed that increases of mental workload can induce accelerations or decelerations of specific processing stages which can be monitored by observing latency changes of the affiliated ERP components.

Adult↗

PubMed2000

On-line driver workload estimation. Effects of road situation and age on secondary task measures.

In order to develop a driver-car interface that adapts the presentation of messages generated by in-vehicle information systems to driver workload, two experiments investigated potential determinants of driver visual and mental workload as indicated by performance on two secondary tasks. Experiment 1 suggested that road situation is a major determinant of visual and mental workload of the driver and that the processing resources of older drivers are somewhat more limited than those of younger and middle-aged drivers. Familiarity with the area of driving (when guided) and time of day (associated with traffic density) showed no secondary task effects. Experiment 2 showed that the categorization of road situations, proposed in Experiment 1, could underlie adaptation of visually loading messages to the workload incurred by driving. This was not found with respect to mentally loading messages.

Adult↗

PubMed1990

Maximum acceptable repetitive lifting workload by Chinese subjects.

This study used psychophysical methods to determine the acceptable mean maximum lifting workload for eight Chinese young male subjects, and examined the effects of lifting technique (including freestyle, stoop and squat), lifting frequency (including 2, 3, 4, 5 and 6 lifts/min) and physical characteristics on the maximum acceptable workload. The results are described as follows: (1) The maximum acceptable weights selected by subjects varied from 11.34 to 18.33 kg with changes in lifting technique and frequency. These data were lower than those previously obtained; (2) The upper limit of physiological tolerance over an 8 h workday was also generally lower than previously suggested. However, this upper limit varied with changes in lifting technique and frequency, and in some circumstances it was the same as or even higher than previous limit; (3) Lifting efficiency was affected significantly by technique and frequency. The rank order of efficiency for three lifting techniques were freestyle, stoop and squat. Efficiency was greatest when lifting frequency was between 5 and 6 lifts/min; and (4) The correlations between the maximum acceptable workloads selected by subjects and anthropometric sizes were significant, but those between maximum acceptable workload and isometric strength were not.

Adult↗

PubMed1999

The influence of aircraft proximity data on the subjective mental workload of controllers in the air traffic control task.

This paper outlines an investigation of the impact of aircraft proximity and relationship data on the subjective mental workload of air traffic controllers. Aircraft relationships were categorized into one of 81 different categories, and these relationships were then used to predict subjective mental workload values (as reported by the participants). The results indicated that this methodology could predict subjective mental workload to an accuracy of 73%, with post-hoc analysis improving this prediction rate to 93%. These results are discussed with respect to their contribution to an understanding of the drivers of mental workload in Air Traffic Control.

Adult↗

PubMed1989

Workload, stress, and strain among police officers.

Data relevant to stress and strain were analyzed separately for police officers with high and low workloads. Although these groups of officers were not found to differ in demographic characteristics or on overall levels of stress and strain, the sources of stress and strain were remarkably different. For the low workload officer, the sources of stress and strain appear to be difficulties in interpersonal relations with peers, community, and especially with supervisors. These difficulties appear to be mediated by effects on self-evaluation. The sources of stress and strain among high workload officers appear to be stress-producing events in their lives in general, as well as in performing the job of patrol officer and in dealing with crime and related matters. The differences between high and low workload officers can be explained by social comparison theory, by identity theory, or by Selye's stress theory.

Achievement↗

PubMed1980

Workload recording by microcomputer.

Workload recording as designed by the College of American Pathologists has proven to be an invaluable aid in the assessment of overall laboratory operation. The administrative information derived from the compilation of these workload statistics is utilized to provide effective and these workload statistics is utilized to provide effective and efficient laboratory management. A microcomputer-based system for the pathology department that permits the accumulation of daily raw workoad data is descirbed. A monthly cummulative summary report is subsequently produced, complete with computer-derived College of American Pathologists workload units.

Computers↗

PubMed1995

Relationship between heart rate and oxygen kinetics during constant workload exercise.

BACKGROUND: Oxygen uptake during constant workload exercise increases exponentially from its resting value before reaching a steady state. The difference between the actual rate of oxygen consumption at the onset of exercise and the steady state is an oxygen deficit. Similarly, the normal sinus node increases its rate at the onset of exercise before achieving a steady state, thereby producing a heart rate deficit. The purpose of this study was to test the hypothesis that elimination of the heart rate deficit by an instantaneous increase in heart rate at the onset of constant workload exercise to the steady-state level would reduce the oxygen deficit and improve the perceived difficulty of exertion as compared with the chronotropic response of the normal sinus node. METHODS AND RESULTS: Ten subjects with normal sinus node function who had DDD pacemakers implanted for AV block completed a symptom-limited maximal treadmill exercise test using the Chronotropic Assessment Exercise Protocol (CAEP) to assess sinus node function, maximal heart rate, and VO2max. The subjects then performed constant workload exercise tests (6-min duration) at a workload equal to approximately 50% of metabolic reserve with the pacemaker randomly programmed to each of three patterns of chronotropic response: (1) DDD (lower rate 60 beats/min); (2) Fast (lower rate abruptly programmed to the expected value at 50% metabolic reserve); and (3) Overpaced (lower rate at least 80% of the age predicted maximum). The oxygen deficit was lower with the fast chronotropic response (434 +/- 238 mL O2) than with either the DDD (512 +/- 233; P = 0.02), or overpaced chronotropic patterns (488 +/- 238; P = 0.02 vs fast). The rate constant for change in VO2 was highest with the fast chronotropic pattern (2.85 +/- 1.38) compared with either the DDD (2.25 +/- 0.64; P = 0.01) or overpaced (2.38 +/- 0.43; P = 0.02) patterns. The Borg perceived exertion rating was lowest with the fast chronotropic response (P = 0.02 vs DDD and P = 0.02 vs overpaced). CONCLUSIONS: The results of this study suggest that oxygen kinetics and exertional symptoms are improved by an abrupt increase in pacing rate at the onset of exercise to a value that is appropriate for metabolic demand as compared with the DDD pacing mode in patients with normal sinus node function. In contrast, an overly aggressive chronotropic response was not associated with improved oxygen kinetics or exertional symptoms.

Adult↗

PubMed1990

Out of hours workload of a suburban general practice: deprivation or expectation.

The out of hours workload of a training practice in a suburban and semirural area on the south coast of England was studied for one year. An overall rate of contact of 273/1000 patients was found, which indicated a workload greater than that reported in most other studies. The duty doctor received over 35 telephone calls from patients during some Saturdays (1200 Saturday to 0800 Sunday) and Sundays (0800 to 0800 Monday), up to five being between 2300 and 0700. Of the patients who contacted a general practitioner, 44% were given advice by telephone and 4.9% were admitted to hospital. The admission rate was lower than that given in other studies. A considerable proportion of the workload arose from doctors covering the casualty department of a cottage hospital. Patients having a high expectation of 24 hour care by general practitioners in an area of comparative affluence (Jarman indices -13.8 to 1.7) may account for this aspect of the workload.

England↗

PubMed1985

A study of workload units in five microbiology laboratories.

A study of a modified Canadian unit system of measuring laboratory workload was undertaken in five joint Public Health Laboratory Service and hospital microbiology laboratories. Ten percent of the specimens received over six months were sampled, the number of units expended on each was recorded, and the results were analysed on a central computer. The process of gathering information in the absence of laboratory computers was time consuming and, despite careful planning, differences were found in the recording practices of the laboratories. The analysis of results did not lead to major changes in data gathering techniques because the same information about laboratory workload could be obtained by collecting numbers of clearly defined specimens. Analysis of workload units could be useful for particular purposes, such as comparing differences between laboratories using different techniques for the same investigation or assessing the possible benefits of automation. It must be appreciated, however, that workload units are measures of quantity not of laboratory performance.

Blood↗

PubMed1994

Toward a psychophysiological assessment of dynamic changes in mental workload.

The main goal of the present study was to examine the feasibility of employing event-related brain potentials to measure dynamic changes in mental workload. Subjects performed two tasks, monitoring and mental arithmetic, both separately and together. Following an analysis of the performance, subjective workload ratings, and average ERP data in the single- and dual-task conditions, two different conditions from each of the tasks were selected for further analysis. A bootstrapping approach was employed to determine the amount of ERP data required to discriminate between these conditions. The results of these analyses indicated that (a) 90% correct discrimination could be achieved with from 1 to 11 s of ERP data, (b) the best ERP measures varied across tasks and subjects, and (c) the inclusion of temporal and spatial aspects of the ERP data improved the ability to discriminate among workload levels. The data is discussed with respect to real-time assessment of mental workload.

Adult↗

PubMed1985

Slow-release nifedipine versus placebo in the treatment of arterial hypertension. A double blind ergometric evaluation of cardiac workload.

The effects of slow-release nifedipine on blood pressure and cardiac workload have been studied during bicycle exercise testing in a randomized, double blind trial in 20 patients with mild to moderate hypertension. After a fortnight's wash-out, patients were allocated to either slow-release nifedipine (20 mg twice daily) or placebo for a 2-month period. At baseline and at the end of treatment blood pressure and heart rate were measured at rest and during ergometric exercise; cardiac workload was calculated as the product of systolic blood pressure by heart rate. Significant decreases in blood pressure at rest and in cardiac workload on exercise were demonstrated at the end of nifedipine treatment. The reduction of cardiac workload was mainly due to the lower baseline values of resting blood pressure. Heart rate showed a reduction of its increase during ergometric exercise at the end of nifedipine treatment as compared to baseline, likely due to an improvement in stroke volume.

Adult↗

PubMed1983

Supply, workload and utilization: a population-based analysis of surgery in rural Manitoba.

This paper explores the relationships among physician supply, workload (output per physician), and utilization (physician services per capita) in rural Manitoba. Surgery taking place within a patient's home area and that taking place outside this area are discussed. Longitudinal and cross-sectional analyses are compared. Although the average surgeon does more surgical procedures than does the average general practitioner, the number of procedures performed varies greatly within each specialty. Individual physician workloads remained fairly stable over time when a surgically active physician moved into an area, while population utilization increased 17 per cent. When such physicians left an area, the surgical workloads of the physicians increased significantly (18.7 per cent) while population utilization stayed essentially the same. Both physician workload and surgical utilization in control areas increased gradually (between 6 and 7 per cent) over the period studied. Several models of physician behavior were investigated using data on individual procedures as well as overall figures. A model emphasizing the importance of physician discretion appeared to provide the best fit with the data.

Economics, Medical↗

PubMed1998

Comparison of cardiac response to managerial workload between men and women.

The aim of the study, was to estimate the reaction of selected circulatory system parameters to psychic workload in industrial managers and to answer the question whether may affect this reaction. The study was performed in 23 men (mean 46 +/- 6 years of age) and 16 women (mean 42 +/- 6 years of age), employed as executives in a large industrial plant. The subjects had their 24-h ECG recorded using Medilog 3000 (Oxford). The ECG recordings were classified as pathological according to the standards of Bjerregaard. Heart rate was calculated for working time, leisure time and sleep. The subjects were also asked to estimate the perceived psychic load according to a method involving subjective estimation of work-demands and of an ability to cope with them. Generally, the subjects reported high work demands, but coping abilities were higher than work demands. Both in the men and women, a relationship was found between the intensity of subjective estimation of psychic load and heart rate response. However, the reaction of the circulatory system to the psychic workload in men was long-lasting (its effects continued until late at night); in women it was more direct (only during work). The frequency of abnormalities in 24-h Holter ECG recordings for both test groups was not very high, a little higher in men (30%) than in women (25%), and was comparable with the frequencies in selected general population groups. Our results may indicate that mental workload of the managerial staff, does not cause increased frequency of ECG abnormalities. However, in view of the fact that cardiovascular diseases are more frequent among men than among women, different reaction of the circulatory system to workload should also be accounted for in an attempt to explain the sources of that phenomenon.

Administrative Personnel↗

PubMed1998

Blood lactate disappearance during breathing hyperoxic gas after exercise in two different physical fitness groups--on the workload fixed at 130% AT.

This study aimed to investigate the effects of hyperoxic gas breathing on the disappearance of blood lactate after exercise in two groups having different physical fitness and to determine the most effective O2 concentration in consideration of workload. Our previous study has demonstrated that hyperoxic gas breathing brought out different effects among subjects. In respect of these effects, it was thought necessary to pay attention to exercise intensity. Therefore, the exercise intensity of this study was set by using relative workload of anaerobic threshold (AT) from the aspect of blood lactate. Ten healthy male students participated as subjects and were divided into 2 groups; a group consisting of 5 active students whose mean AT was 60.4% VO2max (Higher AT group) and the other group consisting of 5 inactive students having the mean AT of 48.8% VO2max (Lower AT group). All subjects underwent three cycles of ergometer exercise on a bicycle (workload; 130% AT) for 5 min and recovery session for 6 min. The hyperoxic gas breathing was given only for the recovery session. The conditions of breathing were air, 30, 40, 60 or 80% O2. Blood for determination of the blood lactate level was taken only in the recovery session. When compared with air-breathing, the blood lactate level was significantly reduced in the condition of more than about 60% O2 breathing in Higher AT group, but not in Lower AT one. Together with the previous findings, it was found that the blood lactate level was markedly reduced by more than 60% O2 breathing in Higher AT group without relation to the workload in the range of about 70 to 80% VO2max. In Lower AT group, however, the effects of hyperoxic gas breathing were dependent on the exercise intensity; 30% and 40% O2 breathings were effective for the subjects with more than about 65% VO2max, but not in a lower intensity than it. These results indicate that the effects of hyperoxic gas breathing on the disappearance of blood lactate are dependent on the exercise intensity and the physical capacity.

Adult↗

PubMed1987

A system of workload measurement for clinical dietitians.

Although the role of the clinical dietitian has undergone dramatic change in recent years, standards for staffing patterns that were developed in 1935 and often still in use. The need for workload measurement systems to quantify the daily activities performed by clinical dietitians led to the development of a new system at the University of Alberta Hospitals in 1984. The workload of clinical dietitians was divided into eight major categories and further divided into 60 activities. A one- or two-week study was conducted four times over an 18-month period. The results indicated that 44 to 54% of the dietitians' time was spent in activities involving direct patient care and team approach. The system has enabled this institution to quantify the workload of its clinical dietitians and may provide a vehicle to measure the impact of major changes on that workload. Since the system covers all possible activities of the clinical dietitian, it may be applicable for use in other institutions. In view of rising health care costs, hospitals must make greater efforts to improve the efficiency of their operations while maintaining the quality of health care services provided to patients. This issue, as it applies to clinical dietetics, was recently addressed by the Nutrition and Food Services Department at the University of Alberta Hospitals.

Alberta↗