Iranian Journal of Ergonomics

Investigating EEG Alpha Variations for Mental Fatigue Detection on Car Driving Simulator

Faramarz Gharagozlou

Introduction: Driver fatigue is one of the major causes of accidents in roads. It is suggested that driver fatigue and drowsiness accounted for more than 30% of road accidents. Therefore, it is important to use features for real-time detection of driver mental fatigue to minimize transportation fatalities. The purpose of this study was to explore the EEG alpha power variations in sleep deprived drivers on a car driving simulator.

Materials and Methods: The present descriptive-analytical study was achieved on nineteen healthy male car drivers. After taking informed written consent, the subjects were requested to stay awake 18 hrs before the experiments and refrain from caffeinated drinks or any other stimulant as well as cigarette smoking for 12 hrs prior to the experiments. The drivers sleep patterns were studied through sleep diary for one week before the experiment. The participants performed a simulated driving task in a 110 Km monotonous route at the fixed speed of 90 km/hr. The subjective self-assessment of fatigue was performed in every 10 minute interval during the driving using Karolinska Sleepiness Scale (KSS). At the same time, video recordings from the drivers face and their behaviors were achieved in lateral and front views and rated by two trained observers. Continuous EEG and EOG records were taken with 16 channels during driving. After filtering and artifact removal, power spectrum density and fast Fourier transform (FFT) were used to determine the absolute and relative alpha powers in the initial and final 10 minutes of driving. To analyze the data, descriptive statistics, Pearson and Spearman coefficients and paired-sample T test were employed to describe and compare the variables.

Results: The findings showed a significant increase in KSS scores in the final 10 minutes of driving (p<0.001). Similar results were obtained concerning video rating scores. Meanwhile, there was a significant increase in the absolute alpha power during the final section of driving (p=0.006).

Conclusion: Driver mental fatigue is considered as one of the major implications for road safety. This study suggests that alpha brain wave rhythm can be a good indicator for early prediction of driver fatigue.

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The Investigation of Association between Psychological Health and Maximum Aerobic Capacity in Male Workers of Industrial Sector of Shiraz

Alireza Choobineh

Introduction: The psychological health is important factor in productivity of workforce and this parameter is effective on maximum aerobic capacity. This study was conducted to investigation of association between of psychological health and maximum aerobic capacity and determination of effective factors on general health in male workers of industrial sector of Shiraz city.

Materials and Methods: In this cross-sectional study, 500 male workers employed in Shiraz city industries participated voluntarily (age range= 20 to 59 years). The demographic questionnaire (including demographic/occupational and anthropometric (height, weight and BMI) and physiological (maximum aerobic capacity) characteristics) and General Health Questionnaire (GHQ-28) were used as data collecting tools. Data were analyzed using statistical tests including T-test and Pearson Correlation by SPSS software (Version 16.0).

Results: Mean (standard deviation) of total score of general health and maximum aerobic capacity of workers were 17.00 (9.99) and 35.95 (7.39) ml.kg-1.min-1, respectively. Statistical analysis revealed significant association between job tenure, BMI, marital status, educational level and shift working with general health. Also, the results showed that there was significantly association between "anxiety and insomnia" subscale and total score of general health with maximum aerobic capacity.

Conclusion: General health was significantly associated with maximum aerobic capacity, job tenure, BMI, marital status, educational level and shift working in studied workers. Normal 0 false false false EN-US X-NONE FA

The Impact of Ergonomics Intervention on Musculoskeletal Disorders among Nahavand Alimoradian Hospital Staff

Majid Motamedzade

Introduction: One of the major problems in hospitals leading to high prevalence of musculoskeletal disorders among the health staff is associated with patients handling. This study was aimed to reduce musculoskeletal disorders using ergonomic intervention among Nahavand Alimoradian hospital staff.

Material and Methods: This study was conducted in four wards of 160-bed Nahavand Alimoradian hospital. The data collecting tool was Nordic Musculoskeletal Questionnaire. SPSS software was used for data analysis. The questionnaire was completed, before and after educational intervention, for 46 employees of the four wards which had the most complaints about musculoskeletal disorders. Training classes were held for the target group covering prevention of work-related musculoskeletal disorders, proper techniques for patient handling and stretching exercises for low back pain prevention.

Results: The main results tended to be the high prevalence of musculoskeletal disorders especially in low back, shoulders and wrists of the employees. Low back pain was the most prevalent disorder among the personnel. The educational intervention had not significant effect on lessening the musculoskeletal disorders in hospital staff (p > 0.05).

Conclusion: At present, regarding enhancements in healthcare procedures, there is an urgent need to ergonomic intervention in the design of environment, tools and equipment concurrent with educational intervention. Normal 0 false false false EN-US X-NONE FA

Job Stress Dimensions and Their Relationship to Job Change Intention among Nurses

Alireza Choobineh

Introduction: Job stress can influence job turnover in organizations. Little data is available on job stress dimensions and their relationship to job turnover among Iranian nurses. The aims of this study were investigating job stress dimensions and examining their relationship to job change intention among nurses.

Materials and Methods: In this cross-sectional study, 385 randomly selected nurses from hospitals of Shiraz University of Medical Sciences participated. The Persian version of Job Content Questionnaire (P-JCQ) and demographic questionnaires were used for data collection. Using SPSS (version 11.5) software, descriptive statistics and Mann-Whitney U test were applied for data analysis.

Results: The means (SD) of decision latitude, psychological job demands, social support, physical job demands and job insecurity were found to be 58.15 (6.50), 38.19 (5.14), 22.67 (3.67), 16.03 (2.58) and 7.74 (3.85), respectively. The results revealed that decision latitude and social support dimensions had low levels, but psychological and physical job demands as well as job insecurity dimensions had high levels among the study subjects. The findings showed that 56.4% of the subjects intended to change their jobs. The mean score of all job stress dimensions had significant relationship with job turnover.

Conclusion: The majority of subjects were exposed to high levels of job stress and most of nurses intended to change their jobs. Based on the results, any interventional program for minimizing job turnover should focus on reducing job insecurity and physical job demands as well as increasing decision latitudes and social support among nurses Normal 0 false false false EN-US X-NONE FA

The Relationship between Workload and Quality of Life among Hospital Staffs

Mehdi Asghari

Introduction: While great efforts have been made to determine the quality of life in hospital staffs, few studies have been conducted to identify the effective factors on the quality of life of these employees. The purpose of the present study was to investigate the relationship between workload and quality of life in hospital personnel.

Material and Methods: In this descriptive-analytical study, 200 staffs were selected randomly from two large hospitals of Tehran University of medical sciences (Imam Khomeini and Shariati hospitals). The data collecting tools were three questionnaires including demographic characteristics, quality of life (SF-36), and NASA-TLX workload. SPSS software (version 18.0) was used to analyze the data by descriptive statistics, and Pearson and Spearman correlation tests.

Results: Based on the findings of the study, the mean total scores of the quality of life and the workload were 50±18 and 69.7±13.9, respectively. The results revealed significant reduction in all dimensions of quality of life in nurses compared with laboratory and operating room staffs. Meanwhile the nurses’ workload scores were higher than the two aforementioned groups (p = 0.001). Moreover, there was a significant inverse relationship between workload and quality of life in hospital staffs (P=0.004, r = -.306).

Conclusion: The results of this study highlight the role of managers and supervisors in the implementation of efficient interventions for improving the quality of life and workload. Therefore, further researches are required to identify other factors that affect the quality of life and workload in hospital staffs. Normal 0 false false false EN-US X-NONE FA

Investigating the Legibility, Readability, Formality and Attractiveness of the most Popular Persian Fonts Used by Students in PowerPoint Slides

Mostafa Pouyakian

Introduction: Lack of attention to the ergonomic measures and standards in making PowerPoint slides can result in visual fatigue, less attention to the content of the lecture and lower quality of training. This study aimed to identify the most popular Persian fonts and font sizes used by students in making PowerPoint slides and to investigate the students' subjective perception of the three features of legibility, formality and attractiveness of these fonts.

Materials and Methods: At first, five most widely used Persian fonts in providing PowerPoint slides were identified in 84 students from Tehran University of Welfare and Rehabilitation Sciences. Then, ten slides were prepared containing simple and familiar sentences based on the five popular fonts and two Different font sizes (24 and 28). Afterwards.40 college students evaluated the eligibility, formality and attractiveness of the fonts and font sizes used in each slide by a seven-item Likert scale.

Results: One-way ANOVA Revealed significant differences between the students' subjective perception of legibility, formality and attractiveness of the fonts used in the slides. In terms of eligibility and attractiveness, slide 10 (B Titr, 28) was top rated and slide 4 (lotus, 24) was ranked as lowest by the participants. In terms of eligibility and attractiveness, slide 10 (B Titr, 28) was top rated and slide 4 (lotus, 24) was ranked as lowest by the participants.

Conclusion: This study explored the effects of anatomical characteristics of the B Nazanin, B Titr and Lotus Persian fonts on the Students’ perception of legibility, formality and attractiveness. The findings suggested that the type of Selected font in PowerPoint slide design could influence the viewers’ perceptual features of legibility, attractiveness and formality. Thus, disregarding the ergonomic aspects of selected Persian fonts may deteriorate the quality of training. Further studies are needed to examine the ergonomics aspects of wider types of Persian fonts in broader sample sizes. Normal 0 false false false EN-US X-NONE FA

Investigating the Consistency of Mental Fatigue Measurements by Visual Analog Scale (VAS) and Flicker Fusion Apparatus

Shirazeh Arghami

Introduction: Mental fatigue is defined as body or soul tiredness which can be caused by stress, overwork, excessive use of drugs or physical or mental illnesses. Fatigue is one of the reasons of productivity loss as well as occurring accidents. Therefore, mental fatigue measurement is of great importance. This study was aimed to determine the consistency of mental fatigue measurement by self-reported VAS and the flicker fusion apparatus.

Material and Methods: A descriptive study was conducted on 30 students. After they had accomplished mental tasks (i.e. mathematical problem solving and responding to MMPI questionnaire), mental fatigued was measured by self-reported VAS and flicker fusion apparatus. To analyze the results, paired sample T-test and Spearman correlation test were applied in SPSS software version 11.5 (P<0.05).

Findings: The results of mental fatigue measurements by both methods of self-reported VAS and the flicker fusion apparatus showed significant increase in mental fatigue after finishing each of the mental tasks. But the findings revealed no consistency between the two methods.

Conclusion: Since self-reported VAS is a subjective technique, it seems that the lack of consistency between the two methods is due to its inefficiency in the mental fatigue measurement. Therefore, further studies with more precise methods such as EEG is suggested. Normal 0 false false false EN-US X-NONE FA

Working Postures Assessment using RULA and Ergonomic Interventions in Quality Control Unit of a Glass Manufacturing Company

Mahtab Azizi

Introduction: Musculoskeletal disorders are amongst dominant occupational injuries and disabilities in developed and developing countries. The RULA technique is one of the best methods for assessing upper limbs postures. The purpose of this study was to investigate the working postures using RULA and ergonomic interventions in the quality control unit of a glass manufacturing company.

Material and Methods: This interventional study was conducted in the mirror control workstations of a glass manufacturing company. To assess workers’ postures, the RULA technique was applied before and after the intervention. After data analysis, corrective engineering measures were recommended and implemented in all workstations.

Results: The findings showed that 40% of workers had a grand score of 7, 40% with a grand score of 6 and 20% with a grand score of 5. Accordingly, 60% of workstations were in action level of 3 (i.e. investigation and changes are required soon) and 40% of workstations were in action level of 4 (i. e. investigation and changes are required immediately). After intervention, 20% of workstations were in action level of 3 and 80% were in action level of 2.

Conclusion: To prevent musculoskeletal disorders, increase work efficiency and improve workforce health, with positive interaction of research team and remarkable cooperation of company management, engineering interventions were designed and implemented at all workstations and the risk level was reduced efficiently. Normal 0 false false false EN-US X-NONE FA