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NIOSH Hearing Loss Research Program Review NIOSH Publications on Noise and Hearing The National Academies - Advisors to the Nation on Science, Engineering, and Medicine

What does the HLR Program Do?

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Research Goal 1

Research Goal 2

Research Goal 3

Research Goal 4

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R&D Portfolio - Research Goal 1.8 : Develop training focused on improving HPD use

Research has consistently demonstrated that, as they are worn in the workplace, HPDs provide only a fraction of their potential sound attenuation. Research has also shown that workers are likely to wear HPDs only a small percentage of the time that they should be worn. Thus, HLPP training must teach workers when and how to use HPDs. Training must also motivate workers to actually use them. In order to accomplish these goals, training must address perceived barriers to HPD use and trainees’ self-efficacy (the belief that he or she has the skills and resources to wear HPDs). There are few examples of training that effectively address these issues.

The HLR program conducted a noise-related HHE for the UBC. The results demonstrated that the majority of carpentry tasks exposed the carpenters to hazardous noise. Audiometric tests demonstrated that the carpenters had substantial noise-induced hearing loss. For example, by age 25, the average carpenter’s hearing was equivalent to that of a 50-year old non-noise exposed worker, i.e., in five years of working in their trade; carpenters were losing 25 years worth of hearing. By age 55, two out of three carpenters were well past the point of needing hearing aids. Protection programs are needed in the construction industry.

The HLR program partnered with the UBC to develop a HLPP for carpenters and other construction workers. The HLR program and the UBC conducted a series of focus groups and administered a new survey instrument to investigate carpenters’ perceptions about HPD use. Data from the survey were used to design the training program. The training program addressed targeted carpenter misperceptions in a multimedia presentation. The program included immediate feedback on hearing test results, as well as hands-on training in fitting and using a 1-year supply of 12 different HPDs that each carpenter was given. The training program was conducted one-on-one with some carpenters and using a more traditional classroom style with other carpenters.

The efficacy of the training program was evaluated in a two-year field study, and in a laboratory-based study of hearing protector attenuation. Regardless of whether the training was administered in a one-on-one or a traditional classroom setting, the training resulted in significant pro-protection changes to every trainee characteristic measured. Training also resulted in a significant increase in HPD use as measured by pre- and post-training work site observations. Finally, training significantly influenced HPD attenuation. HLR program researchers employed new fit-test methodology to quantify the attenuation individuals obtained from their earplugs (see Research Goal 2.2). Naïve workers who fit HPDs with a noise reduction rating (NRR) of 29 dB obtained only approximately 6 dB attenuation. Workers who received one-on-one instruction with the HLR program materials and methods obtained 21 dB of attenuation. The workers who received traditional classroom instruction with the training program obtained 17 dB of attenuation. HLR program researchers concluded that health communication theories could be successfully applied to training program development to dramatically improve HPD effectiveness. The audiometric data demonstrated carpenters have hearing loss consistent with time-weighted average exposures of approximately 97 dB(A). Thus, carpenters who received this training and who wore their HPDs in accordance with this training could reduce their at-the-ear exposure to safe levels.

Currently, audiometric test data are the only measures of a hearing conservation program’s effectiveness, a process that takes 5-10 years. The results of this study will enable faster objective assessments of HLPPs by evaluating training.

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