The ambient noise level and noise-induced hearing impairment (NIHI) in 200 motorbike riders from six motorbike parks were evaluated. All were males aged between 20- 62 years. Subjects were sampled using a cluster sampling technique. Parameters measured were environmental noise using the noise meter (peters) and hearing function using an audiometer (amplaid). A control group of 150 males was selected from amongst the staff of the University of Benin Teaching Hospital and students of University of Benin after informed consent was obtained.
The mean ambient noise for motor bike riders was 90 ±10 dB a level significantly (x=0.000), higher than the International Standard Organization (ISO) standard of 60dB. That for control group was 50 ± 10dB. While there was no NIHI in control group, a significant hearing impairment for both air conduction (AC) and Bone conduction (BC) was observed in the study group. Unlike previous observations AC and BC impairment were predominantly in the left ear. Development of both AC and BC impairments increased with period of exposure.
Environment noise impacts adversely on hearing and is a risk factor in commercial motorbike riders. Development of NIHI is significantly higher in the left ear than right unlike in other occupations.