Hughson Westlake, also termed the ascending method, is an automated pure tone test procedure. It was initially developed in 1944 and modified for automatic testing in the 1960s.
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The Hughson-Westlake method is based on the principle that short-tone burst are better heard against a silent background than a continuous tone separated by a short interval when the level is changing.
This procedure involves short bursts of tone, starting at an audible level, and then decreasing in sets of 10 dB until the point when the patient gives no response. After this point, the tone is increased by 5 dB at a time.
To establish a hearing threshold, two of three, or three of five, ascending responses at the same intensity (dB level) are necessitated. This hearing threshold is then recorded on an audiogram.
How to perform the procedure manually?
- Start by providing the patient with clear instructions. For example, “You will hear a series of tones. Press the response button whenever you hear a tone, no matter how loud or how quiet, or which ear you hear the tones in.”
- Familiarize the patient by presenting an easily audible tone (approximately 50 dB), and check whether the patient responds to it or not.
- If there is no response from the patient, increase the tone by 20 dB and continue until they respond.
- Start the test at the intensity level that was found during this familiarization process.
- Decrease the intensity in levels of 10 dB until the patient no longer responds.
- When the patient fails to respond to the given signal, increase the tone in 5 dB steps until a response is received from the patient.
- To ensure accuracy, repeat steps 5 and 6. To precisely identify and record the patient’s threshold, a minimum of two out of three, or three out of five, identical responses are required.
- Repeat steps 5, 6, and 7 at each frequency included in the test sequence for both ears. A typical sequence would include 1 KHz, 2 KHz, 3 KHz, 4 KHz, 6 KHz, 8 KHz, and 500 Hz. It is required that the test should always begin at 1 KHz, as this is where hearing is most sensitive.
- Ensure that both ears are tested as described above.
How to perform the procedure automatically?
- Start by providing clear instructions to the patient. For instance, “You will hear a series of tones. After hearing the noise, press the response button, no matter at what intensity, loud or quiet, or in which ear you hear the tones.”
- Choose the ‘auto’ test settings on the audiometer.
- The automatic test will be initiated by familiarizing the patient.
- After familiarization, the test will start.
- Start the test at the already known intensity found during the familiarization process.
- The automatic test will follow the same procedure outlined in steps 6, 7, 8, and 9 above for manual testing.
- The obtained threshold/s will be automatically stored.
Which ear should be tested first?
Initiate the test with the better ear. In the absence of a ‘better ear,’ it is not important which one you test first. In cases when hearing is relatively equal in both ears, consistently beginning with a specific ear will be beneficial, as this can help to reduce the risk of error.
The up 5, down 10 rule
After the initial descent to a point when the patient no longer hears the tone, proceed by increasing the intensity in 5 dB steps, and then decrease it by 10 dB until the tone is heard.
The patient’s threshold is established when the lowest level at which they respond in at least 50 % of three trials is determined, and when it is verified that they do not respond to at least 50 % of three trials at a level that is 5 dB lower.
Equipment and training
Amplivox offers a comprehensive range of intuitive and precise audiometry equipment, along with accredited training for professionals to gain expertise in the Hughson Westlake procedure and other types of testing.
References and further reading
Auditdata. What is Auto – Hughson Westlake? Accessible at: https://www.auditdata.com/audiology-solutions/measure/auto-hughson-westlake/
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