Detrimental Effects of Traffic Noise in Traffic Policemen as Assessed by Auditory Brainstem Evoked Response: A Cross-sectional Observational Study

Abstract

Introduction: Loud noise is a global occupational health hazard with substantial social and physiological impacts, especially pronounced in traffic policemen who are engaged at heavy traffic junctions. Apart from its overt effect on sensorineural hearing, loud noise has been also implicated, albeit covertly, as a causative factor for disturbances in sleep, learning and depression. Due to the insidious nature of hearing impairment, manifestations are often masked and hence testing through Auditory Brainstem Evoked Response (ABER) should be resorted to, for assessment of functional status of auditory pathway objectively. Aim: To assess and compare the effect of traffic noise in traffic policemen with age-matched apparently healthy males using ABER. Materials and Methods: The present study was a cross-sectional, comparative type of observational research conducted in the Department of Physiology, SMS Medical College, Jaipur, Rajasthan, India, from June 2019 to May 2020, on 45 apparently healthy male traffic policemen, aged 25-40 years, engaged at heavy traffic junctions of Jaipur city, with an average field posting of five years or more. An equal number of age and sex matched apparently healthy subjects living in Jaipur city, were recruited as controls. Before commencing with the test procedure, ethical clearance was obtained from the Institute’s Ethics Committee and Research review board and written informed consent was obtained from all the participants. ABER assessment was done via RMS EMG SALUS 2C machine on each subject using click stimuli presented mono-aurally via an overhead headphone resulting in harvest of variables in form of absolute wave latencies (I-V) and Interpeak Latencies (IPL) (I-III, I-V and III-V). Unpaired Student’s t-test was used to derive the level of significance using Statistical Package for the Social Sciences (SPSS) version 16.0. Level of significance was set at p-value <0.05. Results: The results obtained in the present study demonstrated pronounced delay (p-value <0.01) in all absolute wave latencies (I-V) in both ears in traffic policemen. A statistically significant delay was also observed in IPL I-V (p-value <0.01) when a comparison of left ABER was made between traffic policemen and controls. Conclusion: The findings of the present study indicate that the hidden footprints of loss in auditory acuity in traffic policemen exposed to traffic noise can be unearthed objectively via using ABER assessment and therefore periodic ABER assessment along with usage of preventive equipment should be the strategy for prevention of imminent hearing loss.

Keywords

• evoked potentials
• hearing loss
• interpeak latency
• noise-induced
• sleep disturbances