NIOSH tools for hearing loss prevention programs

The mining workforce experiences high rates of hazardous noise exposure and hearing loss. However, previous studies have identified specific behavioral and attitudinal barriers that keep miners from effectively acting to prevent their own hearing loss. The National Institute of Occupational Safety and Health (NIOSH) has developed several new hearing loss prevention tools and interventions that specifically target these barriers to prevention. The NIOSH Hearing Loss Simulator addresses motivation to take action and knowledge about the consequences of noise exposure. The QuickFit earplug test device and QuickFitWeb online hearing protection tester address barriers to effective earplug and earmuff use by verifying at least 15 decibels of protection. The NIOSH Roll-Pull-Hold technique helps miners obtain better protection through an easy-to-remember set of steps that improves attenuation by nine decibels. The “Inquiring Ears Want to Know” fact sheet helps miners to understand audiograms and to use them to maintain their hearing health. Each of these interventions can be used within the context of a comprehensive hearing loss prevention program. Introduction The mining workforce experiences high levels of noise exposure and in turn suffers from high rates of noise-induced hearing loss (NIHL). The mining sector has the highest prevalence of hazardous workplace noise exposures (76%) among all industrial sectors (Tak et al., 2009). Although most miners use hearing protection and diligent effort is put forth both by manufacturers and researchers to quiet mining machinery, miners continue to exhibit a high prevalence (24%) of hearing difficulty (Tak and Calvert, 2008). Most U.S. miners are exposed to noise levels that mandate their enrollment in a hearing conservation program (HCP) through their employers. The U.S. Mine Safety and Health Administration’s (MSHA) 1999 Health Standards for Occupational Noise Exposure, codified in 30 CFR 62 (commonly called the “Noise Rule”), requires this step for most miners. The mandatory HCP includes exposure monitoring, annual audiometry, access to hearing protectors, training and recordkeeping. NIOSH recommends additional components beyond those mandated to provide procedural audits, worker motivation, program evaluation and integration of engineering and administrative controls as part of the program. These programs that go beyond the standard hearing conservation program requirements are referred to as hearing loss prevention programs (HLPP) to reflect the more comprehensive and proactive approach (NIOSH, 1996). To enable mines to implement an effective HCP or HLPP the NIOSH mining hearing loss research program has developed a variety of tools and resources. In particular, several tools have been developed to address the need for worker education and motivation to play a critical role in preserving their own hearing. Previous studies have identified attitudinal and behavioral barriers that prevent miners from acting to effectively protect their own hearing. Virtually all of these studies examine the use or non-use of hearing protection, although noise controls are the preferred method of hearing loss prevention. A positive association has been identified between attitudes regarding hearing protection and behavioral intentions to wear hearing protection (Quick et al., 2008). Also, workers who believe that hearing protectors are effective at preventing NIHL are more likely to use HPDs in noisy situations, while those who do not believe that HPDs are effective do not use them consistently. Other factors that reduce hearing protector use include workers’ perceptions that they already have poor hearing, that the devices are uncomfortable and that HPDs can interfere with communications, job performance and the ability to hear warning signals (Morata, 2002). Additional barriers, such as lack of motivation, lack of hearing protector fitting skills and lack of knowledge, can undermine even the most employee-centered hearing loss prevention programs. NIOSH has developed several hearing loss intervention tools targeting specific barriers to effective hearing loss prevention which can be implemented into a comprehensive hearing loss prevention program. Motivation Workers may not take action to protect their hearing because they lack the motivation to do so. Without understanding the consequences of noise exposure on hearing, a worker may have little reason to take any action for protection against noise exposure. The NIOSH Hearing Loss Simulator was developed to motivate miners to protect their ears from noise-induced hearing loss. It is a software training and communication tool that allows for self-experience of the impact of NIHL. Selfexperiences of symptoms have been found to be positively associated with anti-noise attitudes and behaviors (Widen et al., 2009). The purpose of this tool is to motivate workers to protect their own hearing by allowing them to experience the potential hearing loss they may incur with conditions very similar to their “real life” work environment. The main screen of the Hearing Loss Simulator is shown in Fig. 1. Figure 1 — NIOSH Hearing Loss Simulator main screen. A user of the Hearing Loss Simulator can adjust various parameters to estimate the hearing loss one would experience given a specific level of noise exposure over a specific number of years. The effects are shown visually on a frequency band control panel while the user listens to audio playback. Additionally, frequency band sliders are available that allow users to manually input hearing thresholds, from an audiogram, for example, so that a specific hearing loss can be demonstrated. Because hearing in background noise is a more difficult task than hearing in quiet, the Hearing Loss Simulator also offers a variety of background noise conditions for demonstration. Users can select from several recorded mining worksite sounds (continuous mining machine, bulldozers, processing machines), as well as standard generic background noises, such as multitalker babble. Customized sounds may be recorded using a high-quality microphone for further individualization of workplace noise conditions. Through manipulation of these various conditions, a user can experience a range of estimated hearing impairments in a variety of background noise conditions. This variety allows for demonstration of noise conditions that are very similar to a user’s own noise exposures and, therefore, an increased understanding of how their own working conditions may negatively impact their hearing ability. The Simulator gains realism by basing its approximation of the NIHL experience on models derived from hearing impaired populations. The software performs calculations based on the ANSI standard S3.44, Determination of Occupational Noise Exposure and Estimation of Noise-Induced Hearing Impairment (ANSI, 2006). This standard provides algorithms for predicting hearing loss based on age and noise exposure. These algorithms were derived from studies of large populations, including some groups with no exposure to hazardous noise and other groups that experienced various levels and durations of noise exposure. The Simulator can demonstrate the individual variability in susceptibility to NIHL by using its population quartile adjustment. For instance, it can show how much additional NIHL is experienced by individuals in the most susceptible quartiles versus those at the population median. Although no individual user can predict their own susceptibility, the program can show the range of possible expected NIHL. By doing so, the Simulator provides realistic examples of the negative impact of repeated or prolonged noise exposure with data from a large subject pool. The NIOSH Hearing Loss Simulator functions on systems with Windows 98 or higher and standard Windows sound support and speakers. Projectors and/or headphones may be used for certain training applications. The NIOSH Hearing Loss Simulator and the Hearing Loss Simulator Instruction and Training guide are available for download from the internet at: www.cdc.gov/niosh/mining/products/product47.htm. Additionally, these tools can be ordered by calling 1–800–CDC– INFO (1–800–232–4636). Hearing protector fitting skills Lack of hearing protector fit skills is another barrier that impedes workers’ attempts to prevent noise-induced hearing loss. Hearing protection devices (HPDs) marketed in the U.S. are tested in laboratories to determine their Noise Reduction Rating (NRR). This rating is intended to represent the amount of noise protection that the protector can provide. However, the attenuation values obtained at work sites are often much less than those achieved in the laboratory (Berger et al., 1996). With incorrect HPD fit, as often occurs with untrained users, little or no protection from noise may be obtained. NIOSH has developed two tools to aid users of HPDs in achieving adequate fit. The Roll-Pull-Hold method and QuickFit earplug fit tester are NIOSH products aimed to alleviate two specific issues with fitting earplugs. Figure 2 — NIOSH Roll-Pull-Hold method for insertion of