Document Type

Capstone Project

Publication Date


First Advisor

Antony Joseph, MA., Au.D., Ph.D., ABAC, CCC-A, CPS/A, F-NAP


Hearing Loss Prevention, Earplugs, Hearing Protection Devices, Noise-induced Hearing Loss, HPD Well-Fit, Audiology


Communication Sciences and Disorders | Speech and Hearing Science | Speech Pathology and Audiology


Although a long history of research has led to extensive knowledge about hearing protection devices (HPDs), there has been limited research about procedures that provide aid and verification during HPD insertion, although several studies have reported about HPD training. No standard methods have been established for training of earplug use (Takahashi, 2011).

A review of the literature revealed a need for tools that might be used to improve user ability to properly insert HPDs consistently, even in the absence of training, because training is rarely provided in the workplace. The prevailing research question was "Does the use of simple fitting procedures improve attenuation performance?" The research methodology for such an investigation was described, including standardized measurement procedures, attenuation benchmarks, and considerations for study design.

In order to assess whether various intervention strategies might effectively improve worker ability to use HPDs, methods used to measure attenuation, including fit-test instruments, normal-hearing subjects, ANSI standards, and analytical procedures should be aligned. For example, attenuation data may be collected binaurally using HPD Well-Fit™ (a Center for Disease Control [CDC]/National Institutes for Occupational Safety and Health [NIOSH] fit-testing system) prior to and following an intervention. Alternatively, monaural fit-test measurements might be collected for comparison and analysis. Binaural fit-test measurements may be compared to monaural measurements. The data collected may be analyzed to examine which intervention ascertains improvement of attenuation or some other desired outcome. Use of a control group (e.g., subjects that receive no intervention) should reflect the outcome expected in the typical workforce, because, besides a lack of hearing protection training, workers generally do not use earplug fit improvement procedures. Likewise, controls should allow investigators to describe the expected degree of variability in the measurement.

Exploration of simple methods that might be implemented in the noise-exposed workforce is critical for reversal of occupational noise-induced hearing loss. It is important to consider noise-induced hearing loss a public health problem. Further, providers should encourage all patients to practice healthy hearing through the avoidance of hazardous noise despite the lack of evidence-based guidelines (Rabinowitz, 2010).