When occupational noise hazards exceed the exposure standard indicated in occupational health and safety requirements, workers are required to use Personal Hearing Protection (PHP) to reduce the risk of hearing loss. These workers are also required to participate in audiometric testing to ensure the effectiveness of the hearing protection measures.
This audiometric testing may be required annually or every two years, once again depending on your local occupational safety jurisdictional requirements. This article discusses the benefits of audiometric testing and defines exactly what audiometric testing involves.
WHAT IS AUDIOMETRIC TESTING?
Audiometric testing determines workers’ hearing levels with the help of a tool called an audiometer. It is a very simple procedure that involves an employee receiving a series of different tones; for each tone, the participant can respond indicating that they heard the tone.
The tones are presented at different sound levels and checked multiple times to identify the lowest level at which a person can hear. This is called the “threshold limit,” and is compared to a “baseline test.” Audiometric testing is conducted for different frequencies, and both the left and right ears. As a result, it provides a way to monitor the sharpness and acuity of an employee’s hearing over time.
In particular, audiometric testing identifies:
(1) Progressive noise-induced hearing loss before it becomes an impairment.
(2) Temporary loss before it becomes permanent, providing time to implement remedial steps.
ABOUT THE AUDIOMETRIC TEST ENVIRONMENT
To effectively conduct an audiometric test, the test environment must be controlled. In particular, the optimal test environment must be quiet and free of distractions. There should be no distracting activity outside the test room that the listener can see or hear. The listener needs to focus their attention on the test and not any activity surrounding them. For example, while audible speech would not mask the test tones, it would distract the listener.
While there is no such thing as a “soundproof” test room – i.e., a room which no outside sound can penetrate – it is important that rooms are designed to reduce outside noise to the point where it won’t mask the test signals, and it is just as important to not have unnecessary noise-generating activities in the area of the test room.
BENEFITS OF AUDIOMETRIC TESTING
Regularly scheduled audiometric testing identifies people who are at risk of significant hearing loss by identifying changes in their hearing threshold over time. Employers can then implement appropriate treatment plans, like providing a higher class of hearing protection, ensuring that the employee uses hearing protection correctly, and reducing the noise in particular locations.
Audiometric testing is best conducted at least a few hours into an employee’s shift to identify any Temporary Threshold Shift (TTS). Temporary Threshold Shifts can show that the Personal Hearing Protection and noise reduction strategies are not working effectively and that immediate corrective action is required.
Typical hearing loss as a result of Noise Induced Hearing Loss (NIHL) often occurs at the 3K, 4K & 6K frequencies where a V shape notch is observed when viewed on the audiometric graph, known as an audiogram.
Audiometric testing may also assist in identifying the need for diagnosis of potential medical problems, distinct from workplace hearing loss, that affect a person’s ability to hear.