LESSON 59

Preparing for pure-tone audiometry

Name: Preparing for pure-tone audiometry
Uploaded: 2026-11-04T03:15:00+03:00
Duration: 9 min 42 s
Description: An accurate threshold starts with good preparation. In this lesson we go step by step through the test environment, the checks before testing, standard patient instructions and response methods, ear canal collapse and false high-frequency loss, and correct placement of supra-aural earphones and insert foam tips.

Year 1
Spring semester
Audiological Assessment Methods I
Clinical basics and pure tone audiometry
Duration: 9:42

An accurate threshold starts with good preparation. In this lesson we go step by step through the test environment, the checks before testing, standard patient instructions and response methods, ear canal collapse and false high-frequency loss, and correct placement of supra-aural earphones and insert foam tips.

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Hello, and welcome to the AIHEAR Audiology Academy.
In this lesson we will learn the preparation needed before pure-tone audiometry.
We will go step by step through the environment, the patient instructions, checking for canal collapse and placing earphones correctly.
Pure-tone audiometry is done in a sound-treated booth or in a room where ambient noise is low enough.
Maximum permissible ambient noise levels are defined in standards; if exceeded, thresholds may come out worse than they are.
The patient is seated so they cannot see the tester's hands or the device screen, usually sideways or at an angle.
This way the patient responds only to the sound they hear, not to visual cues.
The patient is asked to sit comfortably, switch off their phone and remove anything noisy, such as chewing gum.
The tester should also be positioned to see the patient's face and responses easily.
Testing starts with the case history, which tells you which ear the patient thinks is better.
Then otoscopy is done on both ears, so conditions such as wax, discharge or a perforation are noticed before testing.
During otoscopy, the tendency of the ear canal to collapse under earphone pressure is also checked.
Glasses, earrings and hair clips that would disturb the fit of the earphones are removed.
For patients who use hearing aids, the devices are switched off and removed.
Finally, instructions are given; if these steps are skipped, even the best method can give wrong results.
The instructions first tell the patient what they will hear: short beeps at different pitches, low and high.
They are asked to press the button every time they hear the sound, even if it is very faint.
They are told to press as soon as they hear the sound, and to release it when the sound stops.
It is explained that the ears will be tested one at a time, and which ear will come first.
The instructions are given before the earphones go on, face to face and in plain language.
Finally, a short question checks whether the instructions were understood.
The patient can respond to the sound in different ways, and each method has its own advantages.
The response button lights up on the device and shows clearly when the response happened.
Raising a hand is simple and suits people who struggle with a button, but the tester must watch the patient constantly.
Verbal responses such as saying yes can also be used, but the patient's own voice can briefly disturb listening.
In the clinic the response button is used most often; whichever method is chosen should stay the same throughout the test.
With older patients, it helps to give instructions more slowly and clearly, and in writing when needed.
Telling a patient with tinnitus in advance that the test sound will differ from the ringing and come in pulses makes responding easier.
With young children, play responses are used instead of a button, such as dropping a toy into a box on hearing the sound.
If it seems the instructions were not understood, the test is stopped, the instructions are repeated and the practice is done again.
Watching the patient's attention and fatigue is part of getting reliable responses.
A collapsing ear canal is the closing of the cartilaginous part of the ear canal under the pressure of a supra-aural earphone.
It is more common in older adults, as the cartilage loses elasticity; it can also occur in infants because of their soft canals.
A collapsed canal stops sound reaching the tympanic membrane and falsely worsens thresholds, especially at high frequencies.
As a result, an air-bone gap that does not really exist can appear on the audiogram.
On otoscopy, a narrow or slit-shaped canal entrance is a warning sign.
A simple check is to press the pinna gently towards the head with a finger and see whether the canal closes.
In this example, an older patient's right ear was tested with a supra-aural earphone.
Bone-conduction thresholds are within normal limits.
In air conduction, however, there is a gap of about twenty five to thirty decibels at two thousand and four thousand hertz.
On otoscopy, the canal entrance is slit-shaped, and the canal closes when the pinna is pressed.
This conductive gap seen only at high frequencies is an unexpected finding and strengthens the suspicion of collapse.
To confirm, air conduction is measured again with a method that prevents collapse.
When the same ear is retested with an insert earphone, the air-conduction thresholds come close to bone conduction.
The high-frequency gap disappears, so the gap in the first measurement was caused by collapse.
In this example, the patient's hearing is within normal limits.
The most effective way to prevent collapse is to use insert earphones.
Without inserts, methods such as repositioning the earphone or placing a short support tube in the canal have also been described.
Whichever method was used is stated in the report.
With supra-aural earphones, the red side goes on the right ear and the blue side on the left ear.
The earphone's diaphragm, the center where sound comes out, should sit right over the ear canal entrance.
If the center slips, thresholds may come out worse than they are, especially at high frequencies.
The headband is adjusted to sit on top of the head, and the cushions rest on the pinnae with equal pressure.
No hair, earrings or glasses arms should be left between the cushion and the ear.
The tester puts the earphones on, and the patient is asked not to touch them during the test.
With insert earphones, first choose a foam tip of the right size for the ear canal; most makers offer standard and small sizes.
The foam is rolled between the fingers to make it thin and compressed.
In adults, the canal is straightened by pulling the pinna up and back.
The compressed tip is placed into the ear canal without delay.
The tip is held in place with a finger until the foam expands and fills the canal.
When correctly placed, the outer face of the foam is flush with the canal entrance or slightly inside it.
If the tip is not inserted deeply enough, interaural attenuation decreases and the risk of cross-hearing rises.
Shallow insertion also increases the occlusion effect when the non-test ear is covered during bone conduction.
If the tip presses against the canal wall or the foam does not fully expand, some of the sound may be lost.
A kinked or pinched tube reduces the sound reaching the ear; the tube should hang freely.
Foam tips are single-use, and a new one is used for every patient.
A clinical tip: after fitting the earphones, do a quick side check before starting the test.
Play a clearly audible tone first to the right ear, then to the left, and ask the patient which ear heard it.
This simple check catches earphones put on the wrong way round, or the wrong channel, before testing begins.
If a reversed earphone goes unnoticed, the results of the two ears get mixed up.
Testing starts in a quiet room, after the case history and otoscopy, with items that would disturb the earphones removed.
Instructions are given before the earphones go on, face to face and in plain language, and understanding is checked.
Ear canal collapse can create a false air-bone gap at high frequencies, especially in older adults.
The outer face of the insert tip should be flush with the canal entrance or slightly inside it.
Test yourself: an older patient tested with supra-aural earphones has an air-bone gap only at high frequencies. What comes first to mind?
The correct answer is B: ear canal collapse.
A new measurement with insert earphones shows whether the gap disappears.
In the next lesson we will learn how to find the air-conduction threshold with the modified Hughson-Westlake method.
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Preparing for pure-tone audiometry

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