Iranian Journal of Ergonomics

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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

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Background & Objectives: Shiftwork is a social phenomenon that can have adverse effects on human life. Given the importance of the shiftwork system and caused by the related health problems, the present study was conducted to determine the health status of and shift workers in a hospital. Methods: This cross-sectional study was conducted in one of the hospitals in Razan (Iran). The sample size consisted of 120 medical, administration and service staff. The SOS questionnaire was used for data collection. The data analysis was performed in SPSS software by χ2. Results: The results showed that 98.3% of complaints were about personal, social and familial problems, and 84.9% were related to musculoskeletal disorders. . Satisfaction of rotating shift work and shift work voluntarily chosen variables, the rotation of the shift, shift work and adverse effects on personal life, adverse effects on family life revealed a significant relationship (P<0.05). Instead, insomnia common variables, adverse effects on social life and social problems showed no significant relationship.

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Background: Driver’s fatigue is a major factor contributing to the prevalence of road accidents. A vast number of city dwellers in most countries use public transport bus services to move around the city. Driver’s fatigue causes job burnout and affects the risk of a traffic accident injuring the public. Several methods have been used to date for evaluating mental fatigue however, using questionnaires tends to be a less time-consuming and more accessible technique. The present study was therefore conducted to develop a mental fatigue questionnaire for public transport bus drivers.

Materials and Methods: The study was conducted based on the criteria used for qualitative research. Semi-structured interviews were held with public transport bus drivers using probing questions and data were collected until their saturation so as to enable access to a direct description of mental fatigue by the bus drivers. Data saturation occurred with 30 interviews and sampling was then discontinued. The analysis of the interviews led to the extraction of the themes and an initial list of questionnaire items was then developed. The psychometric properties of the questionnaire were then evaluated through examining the content validity and internal consistency of the items. The content validity of the items was calculated using Lawshe’s table. A minimum CVR of 0.99 and a minimum CVI of 0.75 denoted an acceptable content validity for the items. To determine the internal consistency of the items, 200 bus drivers completed the final version of the questionnaire. The data obtained were then analyzed in SPSS-16 using Cronbach's alpha to measure the reliability of the questionnaire and considering an acceptance level of 0.7.

Results: The interviews conducted at the beginning of the study with 30 drivers led to the emergence of an initial list with 26 items. A total of 9 items with a CVR less than 0.99 were omitted from the list and 17 items with adequate simplicity, clarity and correlation between them and which had a minimum CVI of 0.75 were kept. The questionnaire had a Cronbach's alpha value of 0.87 and was therefore considered a reliable tool.

Conclusion: The questionnaire developed in this study has a good validity and reliability and can therefore be used to assess mental fatigue in public transport bus drivers.