A national approach to noise induced hearing loss

A large multidisciplinary project is being undertaken in New Zealand to investigate the nature of occupational hearing loss and establish a national approach to prevent noise-induced hearing loss (NIHL) in the country. The study builds on the work of Glenis Long whose has made an outstanding contribution to auditory physiology and psychoacoustics. The project covers the New Zealand connection and particularly her involvement in a research program into the monitoring and prevention of noise-induced hearing loss.

This includes estimates of NIHL prevalence and the design and evaluation of education and prevention programs to reduce the impact of noise. Using a modeling approach, the team has estimated that NIHL contributes to 17-25% of cases of hearing impairment in New Zealand and is therefore a significant modifiable risk factor. A key component of the project is monitoring the noise injury. The team is also studying distortion product otoacoustic emissions (DPOAE) as a measure of early injury. To assess DPOAEs as a measure of injury, they have recorded them using swept pure tones and extracted DPOAE components using a least-squares fit approach in noise and non-noise exposed individuals. OAE findings have been compared with measures of auditory function. The team found that the generator component correlated more strongly with auditory threshold and thus may be a better physiological index of noise injury. Overall, these findings have informed a national strategy involving government and community agencies to mitigate the effects of noise.

Source: Univ. of Auckland, School of Population Health

R.S.