Browsing by Author "Darvishi, Ebrahim"
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- Gender differences in cognitive performance and psychophysiological responses during noise exposure and different workloadsPublication . Abbasi, Ali Mohammad; Darvishi, Ebrahim; Rodrigues, Matilde A.; Sayehmiri, KouroshGender can affect the relationship between noise exposure and both cognitive function and comfort; however, evidence is still limited. This study aimed to examine the gender differences in cognitive performance and psychophysiological responses during exposure to noise under tasks with different workloads. Thirty-two participants (16 females and 16 males) with normal hearing and good general health were recruited. They were asked to perform the N-Back test at three levels of workload during exposure to four low-frequency noise conditions: 55, 65, 70, and 75 dB(A). The participants were also asked to judge noise-induced annoyance and subjective fatigue using visual analog scales at the end of each noise condition. The heart rate variability was also recorded using Nexus-4 device before and during each trial and the ratio of low to high frequency (LF/HF) power was analyzed. The results revealed that the females rated significantly higher levels of annoyance and fatigue than the males. The mean accuracy of the women in the level of 55 dB(A) with a medium workload was higher than that of the men, while in higher noise levels the men showed better performance. The response time to the stimulus was also lower in females at different noise levels and workloads. Furthermore, the findings showed that, with increasing noise level and workload, the LF/HF of the women was higher than that of the men Females and males indicated significant and different responses in exposure to different noise levels and workloads. Therefore, this study suggests that gender criteria should be taken into account particularly in the job selection, work content, and design of workplaces.
- Prediction of occupational exposure limits for noise-induced non-auditory effectsPublication . Golmohammadi, Rostam; Darvishi, Ebrahim; Motlagh, Masoud Shafiee; Faradmal, Javad; Aliabadi, Mohsen; Rodrigues, MatildeThere is a recent trend to place more emphasis on noise non-auditory effects. Despite its implications on health, there is a lack of recommendations for noise in occupational settings. This study aimed to present occupational exposure limits for noise-induced non-auditory effects in healthy males using empirical exposure-response regression models based on the data of laboratory and field considering the effective variables. To this end, the equivalent noise level was measured and recorded in four working settings including closed offices, open-plan offices, control rooms, and industrial workplaces during a normal working day. They were 65, 68, 73, and 80dB(A), respectively. In the laboratory, 31 healthy males were exposed to five noise conditions (four noisy conditions and one quiet) during 8 h and they were asked to perform the cognitive tests. In the field phase, 124 healthy males were also examined from four working settings in their workstations for 8 h. The psychophysiological parameters of the participants were recorded in both lab and field. The results indicated variations in mental responses at levels above 55dBA, and psychophysiological variations at levels above 70dB(A) in both phases. The findings also showed that the developed regression models could plausibly predict the noise-induced psychophysiological responses during exposure to noise levels; thus, they can be presented the likely exposure limits. Based on the results of the models, the levels <55dB(A) are likelihood of the acoustic comfort limit, and the levels ranged from 55 to 65dB(A) are the acoustic safe limits. The acoustic caution limit is the likelihood of the levels ranged from 65 to 75dB(A). The levels ranged from 75 to 80dB(A) are likely the action levels or control limits, and the occupational exposure limit are the probability of levels> 80dB(A).