How to Interpret Audiograms

How to Read Hearing Conservation Data

Our bodies are remarkably resilient; however, repeated unprotected exposure to hazardous noise can result in permanent hearing loss. The HCP goal is to prevent this type of injury with engineering and administrative controls, as well as hearing protection.

One key tool is the audiogram. The purpose of this article is to teach how to read these charts.

Intensity

Hearing conservation data is usually presented on a grid pattern with a vertical and horizontal axis. The vertical axis is labeled intensity and the horizontal axis is labeled frequency. Using an audiogram, the softest level of a tone that the individual is able to hear is identified and displayed as a data point on the graph. This data is known as the client’s audiometric threshold. The threshold is used to identify the risk for hearing loss due to hazardous noise exposure. The threshold is a key element in the evaluation and monitoring of an employee’s progress toward their established hearing loss goal. The threshold is a critical element of the four federal agencies’ (OSHA, MSHA, FRA and DoD) respective hearing conservation programs.

With the high turnover of employees at every level in your organization, it is important that new employees maintain their records with as much care as your most tenured staff.

Symbols

A person’s hearing capacity is depicted graphically on a graph called an audiogram. The horizontal axis represents frequency (pitch), from lowest to highest, while the vertical axis measures intensity or loudness, measured in decibels, dB.

Individual thresholds for each frequency are plotted on the graph. The symbols used to represent the results are specific and easy to read. Typically, the right ear’s threshold is plotted in red, and the left ear’s threshold is plotted in blue.

A key to the audiogram symbols is provided with every audiogram form. Reading the key is recommended to ensure that you are interpreting the symbols correctly. This is especially important if you are using bone conduction or air-conduction testing results. The key also provides information about masked and unmasked thresholds. If the thresholds are overlapping, your hearing loss is considered symmetrical. If the thresholds are not overlapping, your hearing loss is considered asymmetrical. This information determines potential next steps.

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