Ergonomic risk factors and musculoskeletal disorders in bank staff: an interventional follow-up study in Iran.

BACKGROUND: Long-term use of computer in a static mode may cause musculoskeletal disorders (MSDs) in bank staff. Considering the high number of bank employees in different countries, such as Iran, the risk factors of these disorders should be investigated in order to implement interventions required to reduce the risk factors. This study aimed to examine the risk factors of MSDs using the Rapid Office Strain Assessment (ROSA) method and to perform an ergonomic intervention program with banking staff in Iran. METHODS: This interventional study was conducted on 277 bank employees in Iran. Subjects were randomly divided into three groups, including a control group (without any intervention), an educational intervention (EI) group, and a group receiving both educational and physical intervention (EPI). Before and after the intervention, the ROSA method and Nordic questionnaire were used to assess the risk factors of MSDs in office jobs and to investigate the prevalence of MSDs. Data were collected 2 weeks before and 9 months following the intervention. RESULTS: Before the intervention, the mean score of ROSA at workstations of all groups was above five with high risk. Nine months after the start of the intervention, there was a significant decrease in the mean ROSA score and its components in the two groups that received the intervention, which was statistically significant (P < 0.001). The results of the study of the prevalence of MSDs in the employees-before the intervention-indicate that the highest prevalence of MSDs in the control group was in areas of the neck (67.1%), back (64.4%), and lower back (63%). In the EI group, the highest prevalence of MSDs was in the neck (65.2%), lower back (61.6%), and back (60.7%) areas. In the EPI group, the discomfort areas were the neck (68.5%), shoulders (66.3%), and lower back (60.9%). Nine months after the intervention, there was a significant decrease in the prevalence of MSDs in the neck, shoulders, and lumbar regions of staff who received the intervention (P < 0.05). CONCLUSION: Nine months after performing the interventions, there was a relative improvement in workstations and prevalence of MSDs in various areas within the bodies of the bank staff. This study showed that using the ROSA method is appropriate for assessing the risk factors of office work and that it can identify deficiencies in workstations. These defects can be addressed by designing and implementing an EI program together with physical interventions according to the components of the ROSA method.

Dynamic Human Error Assessment in Emergency Using Fuzzy Bayesian CREAM.

BACKGROUND: Human error is one of the major causes of accidents in the petrochemical industry. Under critical situation, human error is affected by complex factors. Managing such a situation is important to prevent losses and injury. This study aimed to develop a dynamic model of human error assessment in emergencies in the petrochemical industry. STUDY DESIGN: A cross-sectional study. METHODS: Fuzzy Bayesian network was used to improve the capabilities of the method for determining the control mode. Fuzzy-AHP-TOPSIS method was also used to prioritize emergency scenarios and human error assessment was applied for the most important emergency condition. RESULTS: Fire in a chemical storage unit was recognized as the most important emergency condition. Common Performance Conditions (CPCs) were determined based on the opinions of a panel of 30 experts and specialists and 7 CPCs were selected for emergencies; then, based on the results of AHP method the relative weights were determined. Finally, membership functions, inputs, and outputs of fuzzy sets, CPC values in 8 emergency response tasks, and the probability of control modes were determined using Bayesian Cognitive Reliability and Error Analysis Method (CREAM) method. CONCLUSION: This method could be applied to overcome the weaknesses of traditional methods, provide a repeatable method for human error assessment, and manage human error in an emergency.

Non-Image Forming Effects of Light on Brainwaves, Autonomic Nervous Activity, Fatigue, and Performance.

Fatigue and sleepiness are one of the main causes of human errors and accidents in the workplace. The empirical evidence has approved that, in addition to stimulating the visual system, light elicits brain responses, which affect physiological and neurobehavioral human functions, known as the non-image forming (NIF) effects of light. As recent evidences have shown the positive effects of red or low correlated color temperature white light on alertness and performance, we investigated whether exposure to 2564 K light could improve subjective and objective measures of alertness and performance compared with 7343 K, 3730 K, and dim light (DL) conditions during the daytime. Twenty two healthy participants were exposed to the light while they were performing a sustained attention task and their electroencephalogram (EEG) and electrocardiogram (ECG) were recorded. Both 2564 K and 7343 K conditions significantly reduced EEG alpha-power compared with the DL and 3730 K conditions. Moreover, the 2564 K, 7343 K, and 3730 K conditions significantly reduced subjective fatigue, sleepiness and increased heart rate and performance compared with the DL condition. Furthermore, the effects of light conditions on alertness and performance varied over the day so that more effective responses were observed during the afternoon hours. These findings suggest that light interventions can be applied to improve daytime performance.

The effect of blue-enriched white light on cognitive performances and sleepiness of night-shift workers: A field study.

INTRODUCTION: Night-shift works are basically accompanied by reduced cognitive performance, sleepiness, and higher possibility for human error and related incidents. It is therefore crucial to improve individuals' performance and alertness in sensitive places like industries' control room with the ultimate goal of increasing efficiency and reducing the number of possible incidents. Previous research has indicated that blue light is a critical cue for entraining circadian rhythm. As a result, the present study was an attempt to investigate whether blue-enriched white light illumination was a practical strategy to decrease sleepiness and improve cognitive performance during night shifts. MARTIAL AND METHODS: The study, which adopted a before-after interventional design, was conducted among 30 control room staff members of petrochemical industry. After baseline assessments under existing lighting conditions, every participant was exposed to two new lighting conditions (namely, 17,000K and 6500K blue-enriched white light), each lasting for a week. Assessments were conducted again at the end of these treatments. In order to measure the subjective sleepiness, Karolinska Sleepiness Scale (KSS) was utilized. Subjects also performed the Conners' Continuous Performance Test II (CPT-II) and 1-back test in order to gauge their cognitive performance, and melatonin assessment was carried out using salivary and Eliza technique. The data was analyzed using two-way repeated measure ANOVA. RESULTS: The results indicated that, compared to normal lighting conditions, participants' sleepiness and melatonin rhythm significantly declined when they were exposed to blue-enriched white light. Furthermore, the experimental condition had a significant effect on the reduction of working memory errors. It also decreased omission errors and the reaction time during the sustained attention task. CONCLUSIONS: Thus, using blue-enriched white light may be a proper ergonomic strategy for improving performance and alertness, especially during night, in sensitive environments like control rooms.

The effects of consecutive night shifts and shift length on cognitive performance and sleepiness: a field study.

INTRODUCTION: The aim of this study was to evaluate the effects of consecutive night shifts (CNS) and shift length on cognitive performance and sleepiness. MATERIALS AND METHODS: This study evaluated the sleepiness and performance of 30 control room operators (CROs) working in 7 nights, 7 days, 7 days off (7N7D7O) and 30 CROs working in 4 nights, 7 days, 3 nights, 7 days off (4N7D3N7O) shift patterns in a petrochemical complex on the last night shift before swinging into the day shift. To assess cognitive performance, the n-back test, continuous performance test and simple reaction time test were employed. To assess sleepiness, the Karolinska sleepiness scale was used. RESULTS: Both schedules indicated that the correct responses and response times of working memory were reduced (p = 0.001), while intentional errors and sleepiness increased during the shift work (p = 0.001). CNS had a significant impact on reaction time and commission errors (p = 0.001). CONCLUSION: The main duty of CROs at a petrochemical plant is checking hazardous processes which require appropriate alertness and cognitive performance. As a result, planning for appropriate working hours and suitable number of CNS in a rotating shift system is a contribution to improving CRO performance and enhancing safety.

Effects of Shift Work on Cognitive Performance, Sleep Quality, and Sleepiness among Petrochemical Control Room Operators.

Shift work is associated with both sleepiness and reduced performance. The aim of this study was to examine cognitive performance, sleepiness, and sleep quality among petrochemical control room shift workers. Sixty shift workers participated in this study. Cognitive performance was evaluated using a number of objective tests, including continuous performance test, n-back test, and simple reaction time test; sleepiness was measured using the subjective Karolinska Sleepiness Scale (KSS); and sleep quality was assessed using the Pittsburgh Sleep Quality Index (PSQI) questionnaire. ANCOVA, t-test, and repeated-measures ANOVA were applied for statistical analyses, and the significance level was set at p < 0.05. All variables related to cognitive performance, except for omission error, significantly decreased at the end of both day and night shifts (p < 0.0001). There were also significant differences between the day and night shifts in terms of the variables of omission error (p < 0.027) and commission error (p < 0.036). A significant difference was also observed between daily and nightly trends of sleepiness (p < 0.0001) so that sleepiness was higher for the night shift. Participants had low sleep quality on both day and night shifts, and there were significant differences between the day and night shifts in terms of subjective sleep quality and quantity (p < 0.01). Long working hours per shift result in fatigue, irregularities in the circadian rhythm and the cycle of sleep, induced cognitive performance decline at the end of both day and night shifts, and increased sleepiness in night shift. It, thus, seems necessary to take ergonomic measures such as planning for more appropriate shift work and reducing working hours.