Volume 17, Issue 1 (2020)
ioh 2020, 17(1): 807-822 |
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Research code: 17276
Ethics code: IR.SBMU.PHNS.REC.1398.028
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Niazmand-Aghdam N, Ranjbarian M, Khodakarim S, Mohammadian F, Farhang Dehghan S. Effect of combined exposure to traffic noise and whole body vibration on attention and response control in men. ioh 2020; 17 (1) :807-822
URL: http://ioh.iums.ac.ir/article-1-2850-en.html
URL: http://ioh.iums.ac.ir/article-1-2850-en.html
Nazi Niazmand-Aghdam 
, Mohammad Ranjbarian , Soheila Khodakarim , Farough Mohammadian , Somayeh Farhang Dehghan *
, Mohammad Ranjbarian , Soheila Khodakarim , Farough Mohammadian , Somayeh Farhang Dehghan *
Shahid Beheshti University of Medical Sciences , somayeh.farhang@gmail.com
Abstract: (2415 Views)
Background and aims: Road traffic noise is one of the most common sources of environmental noise which has various effects on mental and physical health, impaired daily life function and cognitive performance. Vibration is another achievement of industrial development that is accompanied by noise in most work environments. Vibration transmitted from road surface to vehicles and drivers may interfere with activities, affect their comfort level and reduce attention. The purpose of this study was to compare the effect of independent and simultaneous exposure to traffic noise and whole body vibration on visual and auditory attention and control response of males using Integrated Visual Auditory Performance Test (IVA + PLUS).
Methods: The study population included 24 male students aged 18 to 30 years old in Shahid Beheshti University of Medical Sciences who had inclusion criteria for the study. The experiments were performed in 4 steps randomly in one day for each person in the acoustic room and in total, 96 experimental runs (24 runs per step) were performed. Inclusion criteria included: Students in the age group of 18-30 years, no history of underlying diseases including respiratory problems, skin disorders, sleep and cardiovascular disorders and other health problems affecting one's muscular and brain health, no short term illnesses during the trial (colds, diarrhea and vomiting), no history of upper limb musculoskeletal disorders, hearing loss less than dBA27, visual acuity above (7/10), no smoking addiction and drugs and alcohol, no use of hypnotic drugs and CNS attenuating drugs during the test period, not being over sensitive to sound according to Weinstein noise sensitivity questionnaire and getting a score of 22 or below in General Health Questionnaire, which reflects the health of the individuals. Exclusion criteria also included: a person's unwillingness to continue participating because of the long study's time and people who did not meet the above criteria. Subjects did the IVA test (data recorded including scores of total attention and response control scores) in background conditions (sound level dBA 27 and vibration acceleration zero), then they were exposed to individual and combined noise level of 55 dBA (as the permissible sound pressure level at outdoors) and the vibration acceleration of 0.65 m/s2 (as the average acceleration vibration in the Iranian vehicles). In this study, a vibration simulator was used to generate a vibration in the x, y, and z axes at different frequencies and intensities, either sinusoidal or randomly using a vibrating engine. The Italian OLI VIBRATOR MVE.440 / 2M vibrating engine was attached to the seat using a metal stand. The Ic5 inverter was used to adjust the vibration frequency and acceleration and the whole body vibration meter according to ISO 2631 was used to ensure the calibration of the vibration produced by the vibration simulator. The noise used in this study was generated by the signal software with combining the desired frequency and these computer-generated audio files were performed in the Cool edit tool software during the test. One of the features of this software is the ability to edit the sound in intensity at different frequencies, and by continuously monitoring noise in the acoustic room, the volume of the noise can be controlled at the desired frequencies. During the exposure, the intensity of noise within the individual's hearing range, inside the acoustic room was controlled by a calibrated B&K 2238 Sound Level Meter. The IVA is an 8-minute visual and auditory continuous performance test that assesses total attention and response control scores. The task of the participant is to react when the number 1 is seen or heard and to click on the mouse once, and don’t react when the number 2 is seen or heard. The task type assigned to the participants was "simple", its physical workload was "light". Participants signed written consent form and filled demographic information form, general health questionnaire (GHQ-28), and Weinstein noise sensitivity scale. Audiometric and the E eye chart tests were done for hearing and visual acuity testing. To determine the individual and combined effect of noise and whole body vibration on attention and response control, regression analysis of repeated measures using generalized estimating equations with first order autoregressive process was used.
Results: The mean (±SD) age of the participants were 23.41 ± 2.99 years. In the visual test and in the background vibration acceleration, the mean scores of attention has been increased with increasing traffic noise from 27 to 55 dBA and the response control score has been decreased (P = 0.79 and P = 0.1, respectively). At the background noise level, mean scores of attention and response control have been increased with increasing vibration acceleration from zero to 0.65 m/s2 (P = 0.49 and P = 0.59, respectively),). In combined exposure condition with noise level 55 dBA and vibration acceleration of 0.65 m/s2, the mean score of attention decreased compared to background ones (P= 0.95), and the response control score increased compared to background ones (P= 0.72). In the auditory test and in the background vibration acceleration, the mean scores of attention and response control have been increased by increasing the traffic noise from 27 to 55 dBA (P = 0.02 and P = 0.13, respectively), At the background noise level, mean scores of attention were significantly reduced by increasing the vibration acceleration from zero to 0.65 m/s2 (P =0.01). Mean scores of response control has been increased with increasing vibrational acceleration from zero to 0.65 m/s2 (P=0.74). In combined exposure condition, the mean scores of attention were significantly lower than background ones (P =0.01), and the response control score has been increased compared to the background ones (P= 0.09).
Conclusion: Similar results were found regarding the combined effect of noise level 55 dBA and vibration acceleration of 0.65 m/s2 on the total level of attention and response control in visual and auditory tests. So that the simultaneous increase in noise level and vibration acceleration relative to the background condition leaded to decrease in the total score of attention in both visual and auditory dimensions. However, in the mentioned conditions, the response control score has been increased in both visual and auditory tests. It seems that the score of response control, which in some way expresses the ability to sustain attention and the reaction speed during the test, has been increased as a result of noise motivation theory and the positive short-term effects of vibration acceleration. In general, whole body vibration in low to moderate acceleration level and low level of noise may improve cognitive performance in a short time, however, definitive conclusions are subject to doing the systematic and comprehensive studies.
Methods: The study population included 24 male students aged 18 to 30 years old in Shahid Beheshti University of Medical Sciences who had inclusion criteria for the study. The experiments were performed in 4 steps randomly in one day for each person in the acoustic room and in total, 96 experimental runs (24 runs per step) were performed. Inclusion criteria included: Students in the age group of 18-30 years, no history of underlying diseases including respiratory problems, skin disorders, sleep and cardiovascular disorders and other health problems affecting one's muscular and brain health, no short term illnesses during the trial (colds, diarrhea and vomiting), no history of upper limb musculoskeletal disorders, hearing loss less than dBA27, visual acuity above (7/10), no smoking addiction and drugs and alcohol, no use of hypnotic drugs and CNS attenuating drugs during the test period, not being over sensitive to sound according to Weinstein noise sensitivity questionnaire and getting a score of 22 or below in General Health Questionnaire, which reflects the health of the individuals. Exclusion criteria also included: a person's unwillingness to continue participating because of the long study's time and people who did not meet the above criteria. Subjects did the IVA test (data recorded including scores of total attention and response control scores) in background conditions (sound level dBA 27 and vibration acceleration zero), then they were exposed to individual and combined noise level of 55 dBA (as the permissible sound pressure level at outdoors) and the vibration acceleration of 0.65 m/s2 (as the average acceleration vibration in the Iranian vehicles). In this study, a vibration simulator was used to generate a vibration in the x, y, and z axes at different frequencies and intensities, either sinusoidal or randomly using a vibrating engine. The Italian OLI VIBRATOR MVE.440 / 2M vibrating engine was attached to the seat using a metal stand. The Ic5 inverter was used to adjust the vibration frequency and acceleration and the whole body vibration meter according to ISO 2631 was used to ensure the calibration of the vibration produced by the vibration simulator. The noise used in this study was generated by the signal software with combining the desired frequency and these computer-generated audio files were performed in the Cool edit tool software during the test. One of the features of this software is the ability to edit the sound in intensity at different frequencies, and by continuously monitoring noise in the acoustic room, the volume of the noise can be controlled at the desired frequencies. During the exposure, the intensity of noise within the individual's hearing range, inside the acoustic room was controlled by a calibrated B&K 2238 Sound Level Meter. The IVA is an 8-minute visual and auditory continuous performance test that assesses total attention and response control scores. The task of the participant is to react when the number 1 is seen or heard and to click on the mouse once, and don’t react when the number 2 is seen or heard. The task type assigned to the participants was "simple", its physical workload was "light". Participants signed written consent form and filled demographic information form, general health questionnaire (GHQ-28), and Weinstein noise sensitivity scale. Audiometric and the E eye chart tests were done for hearing and visual acuity testing. To determine the individual and combined effect of noise and whole body vibration on attention and response control, regression analysis of repeated measures using generalized estimating equations with first order autoregressive process was used.
Results: The mean (±SD) age of the participants were 23.41 ± 2.99 years. In the visual test and in the background vibration acceleration, the mean scores of attention has been increased with increasing traffic noise from 27 to 55 dBA and the response control score has been decreased (P = 0.79 and P = 0.1, respectively). At the background noise level, mean scores of attention and response control have been increased with increasing vibration acceleration from zero to 0.65 m/s2 (P = 0.49 and P = 0.59, respectively),). In combined exposure condition with noise level 55 dBA and vibration acceleration of 0.65 m/s2, the mean score of attention decreased compared to background ones (P= 0.95), and the response control score increased compared to background ones (P= 0.72). In the auditory test and in the background vibration acceleration, the mean scores of attention and response control have been increased by increasing the traffic noise from 27 to 55 dBA (P = 0.02 and P = 0.13, respectively), At the background noise level, mean scores of attention were significantly reduced by increasing the vibration acceleration from zero to 0.65 m/s2 (P =0.01). Mean scores of response control has been increased with increasing vibrational acceleration from zero to 0.65 m/s2 (P=0.74). In combined exposure condition, the mean scores of attention were significantly lower than background ones (P =0.01), and the response control score has been increased compared to the background ones (P= 0.09).
Conclusion: Similar results were found regarding the combined effect of noise level 55 dBA and vibration acceleration of 0.65 m/s2 on the total level of attention and response control in visual and auditory tests. So that the simultaneous increase in noise level and vibration acceleration relative to the background condition leaded to decrease in the total score of attention in both visual and auditory dimensions. However, in the mentioned conditions, the response control score has been increased in both visual and auditory tests. It seems that the score of response control, which in some way expresses the ability to sustain attention and the reaction speed during the test, has been increased as a result of noise motivation theory and the positive short-term effects of vibration acceleration. In general, whole body vibration in low to moderate acceleration level and low level of noise may improve cognitive performance in a short time, however, definitive conclusions are subject to doing the systematic and comprehensive studies.
Type of Study: Research |
Subject:
Physical agents at work
Received: 2019/07/8 | Accepted: 2019/12/10 | Published: 2020/09/23
Received: 2019/07/8 | Accepted: 2019/12/10 | Published: 2020/09/23
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