Auditory threshold profile of Indian automobile drivers

Abstract

Noise and vibration are occupational hazards, which affect the workers health and safety. Prolonged exposure to noisy environment results in hearing loss of the affected individuals. The objective of this study was to assess the hearing threshold profiles of automobile drivers in Kolkata, India. In this study, 90 healthy male subjects of similar age, height and weight were divided into three groups of 30 each viz. drivers with less than 10 years of experience, drivers with more than 10 years of experience and office workers. The audiometric testing of both the ears of the selected subjects were conducted at 125, 250, 500, 1000, 1500, 2000, 3000, 4000, 6000, 8000 and 10000 Hz. The hearing threshold levels of office workers at audiometric test frequencies of 0.5, 1, 2 and 3 kHz did not exceed 25 dB to cause hearing handicap. However, it exceeded 25 dB(A) for automobile drivers. Two tail ‘t’ test for large samples of identical size was used to investigate the difference in audiometric status of both ears between drivers of more than 10 years experience and office workers, drivers of less than 10 years experience and office workers and between drivers of more than 10 years and less than 10 years experience. Statistical analysis of the data revealed significant differences in the audiometric profile of the drivers in comparison to the office workers. Overall results indicated that long term and continuous exposure to automobile sound accompanied by environmental sound was the principle cause of the poor audiometric status of the drivers. Automobile drivers should use personnel protective devices such as ear plugs, ear muffs etc to protect themselves from hearing loss.