Daily Exposure Monitoring to Prevent Hearing Loss

Despite the existence of an OSHA standard for hearing conservation, noise-induced hearing loss continues to be one of the most prevalent occupational conditions. Furthermore, hearing loss rates appear to vary significantly between industrial locations with similar measured noise exposure levels. The factors that determine an effective hearing conservation program remain poorly understood. The effective use of hearing protection, believed to be a critical component of such programs, is felt to be highly variable in real world situations. Provocative new data by our research group indicate that much of the preventable hearing loss in a large industrial workforce is occurring not among the workers in the highest ambient noise areas, but instead among employees working in areas where measured ambient median noise exposures are close to or even slightly below the current OSHA action level (85dBA for an 8 hour time weighted average). One possible reason could be that the use of hearing protection is currently less effective in such areas of lower or intermittent noise compared to high noise areas. Since in many worksites, the majority of workers are exposed to moderate noise levels, there is an urgent need to better understand how to prevent hearing loss in these settings. There are also currently no national guidelines for ensuring correct fit and function of hearing protection, and there is an urgent need to find ways to promote the correct use of hearing protective devices. This study will assess the impact of hearing protector fit testing and daily noise exposure monitoring, with major implications for hearing conservation practice, and the wider prevention of noise-induced hearing loss. It will also explore the role of hearing protective devices in areas of median noise exposure less than 85dBA.

This proposed study is a worksite intervention trial of a new technology to reduce occupational noise-induced hearing loss. The intervention will test the effectiveness of a noise exposure dosimeter, the QuietDose - essentially a small microphone connected to a noise logging device about the size of a beeper- that measures a worker's daily noise "dose", as well as peak noise exposure, inside of the worker's hearing protectors. Workers and the study coordinator receive daily feedback about noise exposures (if the device was used outside of the study it would be safety personnel that received the feedback outside of the workers themselves). Such feedback will allow steps to be taken to minimize such exposures, such as behavioral adjustments and improved awarenessThe goal of this study is to determine whether daily assessment and feedback of workers' noise exposures leads to more effective use of hearing protection and prevention of noise-induced hearing loss. The proposed study will take advantage of the unique working relationship between a research institution (the Yale Occupational and Environmental Medicine Program) and a major industrial corporation (Alcoa, Inc.) to conduct this intervention trial at several of the company's facilities.