Measuring earplug noise attenuation: A comparison of laboratory and field methods

Abstract

Hearing protection device (HPD) fit-testing is a recommended best practice for hearing conservation programs as it yields a metric of the amount of attenuation an individual achieves with an HPD. This metric, the personal attenuation rating (PAR), provides hearing health care, safety, and occupational health personnel the data needed to select the optimal hearing protection for the occupational environment in which the HPD will be worn. Although commercial-off-the-shelf equipment allows the professional to complete HPD fit tests in the field, a standard test methodology does not exist across HPD fit-test systems. The purpose of this study was to compare the amount of attenuation obtained using the “gold standard” laboratory test (i.e., real-ear attenuation at threshold [REAT]) and three commercially available HPD fit-test systems (i.e., Benson Computer Controlled Fit Test System [CCF-200] with narrowband noise stimuli, Benson CCF-200 with pure tone stimuli, and Michael and Associates FitCheck Solo). A total of 57 adults, aged 18 to 63, were enrolled in the study and tested up to seven earplugs each across all fit-test systems. Once fitted by a trained member of the research team, earplugs remained in the ear throughout testing across test systems. Results revealed a statistically significant difference in measured group noise attenuation between the laboratory and field HPD fit-test systems (p < .0001). The mean attenuation was statistically significantly different (Benson CCF-200 narrowband noise was +3.1 dB, Benson CCF-200 pure tone was +2.1 dB, and Michael and Associates FitCheck Solo was +2.5 dB) from the control laboratory method. However, the mean attenuation values across the three experimental HPD fit-test systems did not reach statistical significance and were within 1.0 dB of one another. These findings imply consistency across the evaluated HPD fit-test systems and agree with the control REAT test method. Therefore, the use of each is acceptable for obtaining individual PARs outside of a laboratory environment.

Keywords:

• Fit-test
• hearing conservation
• hearing protection device
• real-ear attenuation at threshold

Acknowledgments

The authors of this report would like to thank the participants who made this project possible.

Data availability statement

The datasets generated during and/or analyzed during the current study are not publicly available due to government restrictions regarding data sharing but are available from the corresponding author on reasonable request and when requirements are met.

Disclaimer

The views expressed in this article are those of the authors and do not necessarily reflect the official policy or position of the Department of the Navy, Department of Defense, nor the U.S. Government. Reference in this paper to any specific commercial product, process, or service or the use of any trade, firm, or corporation name is for the information and convenience of the public, and does not constitute endorsement, recommendation, or favoring by the Department of the Navy. This work was prepared by employees of the U.S. Government as part of their official duties. Title 17 U.S.C. §105 provides that ‘Copyright protection under this title is not available for any work of the United States Government.’ Title 17 U.S.C. §101 defines a U.S. Government work as a work prepared by a military Service member or employee of the U.S. Government as part of that person’s official duties.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This work was supported by the U.S. Navy Bureau of Medicine and Surgery funding work unit F1016.