Understanding
Audiological Results
in Victoria BC
Information For Health Care Providers - Understanding Audiograms & Reports
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​Pure Tone Audiometry
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Pure Tone Audiometry (Air Conduction)
Pure tone audiometry is a behavioural hearing test used to detect an individual's hearing threshold levels. The test works by delivering pure tones at one-octave frequencies between 250 and 8000 Hz via headphones or insert ear phones. The level of these pure tones is then reduced to the quietest level at which a patient can detect the tone, which is defined as the hearing threshold, recorded in dB HL.
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Pure Tone Audiometry (Bone Conduction)
The test works by delivering pure tones at one-octave frequencies between 500 and 4000 Hz via a bone conduction headband (bypassing the outer and middle ear, stimulating the cochlea directly). The level of these pure tones is then reduced to the quietest level at which a patient can detect the tone, which is defined as the hearing threshold. Comparing air and bone conduction thresholds allows a hearing care professional to determine the type of hearing loss an individual has (sensorineural, conductive, or mixed).
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Extended High Frequency Audiometry (Air Conduction)
This test extends the frequency range beyond conventional air conduction audiometry (>8000 Hz), providing a more detailed assessment of hearing for very high-frequency sounds. This can be especially useful for early detection of hearing loss in ototoxicity-related or noise-related changes in hearing, as well as for tinnitus assessment and management.
Loudness Discomfort Levels (LDL)
This is the level in dB HL at which a patient feels pure tones become uncomfortably loud.
Interpretation of the Audiogram
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Normal hearing
If both air conduction and bone conduction results are within 10 dB of each other and within normal limits.
​Conductive hearing loss
When air conduction thresholds are outside normal limits, while bone conduction thresholds are within the normal limits, creating what is called an air-bone gap. Conductive hearing loss arrises from the outer or middle ear (e.g., ear infection, earwax blockage, or damage to the tympanic membrane or ossicles).
Sensorineural hearing loss
When both air conduction and bone conduction thresholds are outside normal limits within 10 dB of each other. Sensorineural hearing loss arrises from the cochlea (sensory) or auditory nerve (neural).
Mixed hearing loss
When there is both conductive and sensorineural hearing loss. Air conduction is worse than bone conduction by more than 10 dB (creating an air-bone gap), and both air conduction and bone conduction hearing thresholds are outside of normal limits.
Speech Audiometry
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Speech audiometry is an umbrella term used to describe a collection of audiometric tests using speech as the stimulus.
Speech audiometry is a core test in the audiologist’s test battery because pure tone audiometry is a limited predictor of a person’s ability to recognize speech. Improving an individual’s access to speech sounds is often the main motivation for fitting them with a hearing aid. Therefore, it is important to understand how a person with hearing loss recognizes or discriminates speech before fitting them with amplification, and speech audiometry provides a method of doing this.
Speech audiometry may include the following tests:
Speech detection threshold (SDT)
This is the level in dB HL at which the patient detects speech is present 50% of the time correctly.
Speech recognition threshold (SRT)
This is the level in dB HL at which the patient recognizes 50% of the test material correctly.
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Most comfortable loudness level (MCL)
This is the level in dB HL at which the patient feels speech is most comfortable to listen to and understand.
Uncomfortable loudness level (UCL)
This is the level in dB HL at which the patient feels speech becomes uncomfortably loud.
Word recognition score (WRS)
This score is expressed as a percentage of words correctly repeated at a specified intensity level.
Quick Speech-in-Noise (QuickSIN)
This score is expressed as a dB signal-to-noise-ratio (SNR) loss at a specified intensity level.
SNR loss can be considered as the patient’s hearing performance in noise compared to a normal-hearing person’s performance in noise. SNR loss is defined as the dB increase in SNR required by a hearing-impaired person to understand speech in noise, compared to someone with normal hearing.
A normal-hearing person requires about +2 dB SNR (speech louder than the background noise by 2 dB) to identify 50% of key words in sentences on the QuickSIN test.
Tympanometry
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An objective test that evaluates the function of the middle ear system. Possible tympanogram results:
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Acoustic Stapedial Reflex Thresholds
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The acoustic reflex is the contraction of the stapedius and tensor tympani muscles in the middle ear in response to the presentation of a loud sound. The contraction of these muscles leads to a stiffening of the ossicular chain and causes a change in compliance of the middle ear system.
This reflex is thought to offer some protection to the inner ear against loud stimulus levels and occurs bilaterally. As a result, you can measure the acoustic reflex both ipsilaterally and contralaterally.
Acoustic reflex testing provides objective information about the neural pathway involved in the acoustic reflex. It can help to differentiate between middle ear vs conductive issues, inner ear vs. sensorineural problems, and eighth cranial nerve pathologies.
Otoacoustic Emissions (OAEs)
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Otoacoustic emissions (OAEs) are sounds produced by the movement of outer hair cells within a properly functioning cochlea when stimulated by external sounds. These emissions can be measured using a specialized probe equipped with speakers and a microphone, placed in the external auditory canal (ear canal). OAEs serve as objective indicators of the outer hair cells' integrity and function within the cochlea, providing valuable insights into auditory health.
Tinnitus Characterization Measurements
Tinnitus Pitch Matching
This is the frequency in Hz that best matches the patient's perceived tinnitus pitch.
Tinnitus Loudness Matching
This is the loudness in dB SL that best matches the patient’s perceived tinnitus loudness.
Minimum Masking Level (MML)
This is the volume in dB SL that is required for broadband or narrowband noise to completely mask the patient’s tinnitus.
Residual Inhibition
This test determines whether tinnitus suppression persists beyond masking noise presentation.