Let’s take a look at the most common types of hearing assessments
Most people think of pure-tone audiometry when considering hearing tests, but audiologists may explore many different tests with you. Often, a combination lets them determine which issues are responsible for your hearing trouble.
This article explores the various hearing test types available, including those at The Hearing Space. The more comprehensive the testing, the better the audiologist can understand how your hearing loss may affect your daily life and offer solutions. Let’s look at ‘Understanding the Different types of hearing tests’ that are available.
Pure-tone Audiometry
The pure-tone audiometry test is a standard option for most audiologists that measures hearing sensitivity across a range of acoustic frequencies. The purpose is to detect hearing thresholds at different pitches to build an audiogram–a plot of the shape of the hearing loss.
Audiologists use an audiometer, a device that generates pure tones (with smooth sinusoidal waves), to send sounds to a pair of headphones you wear. You then listen to tones as they come through, indicating to the audiologist when you can hear them (usually by pressing a button).
The frequency of pure-tone audiometry ranges from lows of 250 Hz up to 8,000 Hz. This distribution tests your hearing’s full range at different intensities, showing whether you are having trouble hearing deeper sounds, higher ones, or tones across the board.
These results are then used to create an audiogram. This chart plots pitch along the X-axis and volume intensity along the Y. It reveals whether you have mild, moderate, severe, or profound hearing loss and where you have the most difficulty along the frequency spectrum. It also determines the type of hearing loss, whether conductive or sensorineural, allowing the audiologist to suggest more suitable treatment.
Pure-tone audiometry can be used to prescribe hearing aids or other assistive devices. It is also sometimes necessary before medical or surgical interventions. It can even allow audiologists to establish the effect of ototoxic substances on hearing, providing a basis for switching medications.
Different Types of Hearing Tests: Middle Ear Tests
Middle ear tests are a collection of hearing evaluations used throughout the UK. They focus on investigating the workings of the middle ear (the parts of the hearing mechanism from the eardrum to the cochlea).
The purpose of middle ear tests is to provide more details on how well middle ear structures function. As such, these evaluations help diagnose ear fluid buildup, negative pressure issues, amongst other things.
Tympanometry
Tympanometry is a test that measures the eardrum’s ability to move and respond to incoming sounds. Audiologists often use it if they expect glue ear (middle ear fluid
Tympanometry starts by inserting a probe into the ear canal and creating an airtight seal around it. The device then emits a tone to change the pressure in the ear canal, impacting the eardrum. It records how the tissue moves and sends the details to the recording equipment.
Audiologists usually classify the results of tympanometry into three classes.
Type A refers to normal middle ear pressure, suggesting that the eardrum is healthy and functioning as it should. Under this scenario, a middle ear infection is less likely and evidence of barotrauma is minimal.
Type B refers to a “flat line” situation where the eardrum doesn’t respond to incoming sounds as strongly as it should. Usually, a reading like this results from anything that changes the tension characteristics of the eardrum, such as fluid buildup or stiffness of the eardrum. Type B can indicate the presence of infection or trauma from sudden pressure changes, warranting further investigation.
Finally, type C readings indicate negative pressure. This classification can indicate a receding infection or problems with the eustachian canal, the small tube that connects the ears to the throat.
Eustachian Tube Function Test
Eustachian tube function tests explore how well the eustachian tube regulates pressure in the middle ear. Ideally, there should be a two-way flow along this canal, but it can become blocked.
Most audiologists assess eustachian tube function with a form of tympanometry.
Normally, the eustachian tube will equalise the pressure between the middle ear and the rest of the environment. However, abnormal results can indicate a blockage or pressure-related trauma.
Usually, tube function tests suggest the presence of middle ear fluid, although other issues can be at play.
Acoustic Reflex Testing
Middle ear tests can also include acoustic reflex testing. This procedure evaluates the ability of the stapedius muscle to contract in response to loud sounds.
The stapedius is a small muscle in the middle ear that holds the sound-conducting bones in place and protects against loud noises. When it isn’t functioning properly, it doesn’t activate, allowing louder sounds through to the cochlea.
Different Types of Hearing Tests: Otoacoustic Emissions Test
Different Types of Hearing Tests: Otoacoustic emissions tests assess cochlear function, specifically the ability of the tiny hair-like structures inside the organ to detect and respond to incoming sound waves. This test is useful for determining sensorineural hearing loss in older adults and congenital deafness in children/newborns.
Otoacoustic emissions result from the cochlear’s natural amplification process. Sounds entering the tissue cause the outer hair-like cells to vibrate, enhancing the incoming signal. This action generates more acoustic energy, which travels back to the middle ear.
Audiologists use a range of otoacoustic emissions (OAEs) to determine inner ear function. Transient and Distortion Product OAEs are the most popular, where hearing health professionals play sounds into your ear and listen for resulting OAEs using probes.
Transient-evoked OAEs take the form of rapid clicks or burst sounds across various frequencies. These measure the immediate responsiveness of the cochlear to stimulation.
Distortion-product OEAs use a stimulus of pure tones played together. These allow more characterisation of the frequency emission (because of their interaction), to provide a more detailed hearing assessment.
Otoacoustic emission testing typically starts with you sitting in a quiet, sound-proofed room. The audiologist then places a probe in your ear containing a small speaker (to emit the required sounds) and an ultra-sensitive microphone to detect cochlear emissions. The equipment pipes sound into the ear and uses the microphone to record OAEs. This information is then sent to a computer to crunch the data and suggest various diagnoses.
Otoacoustic emission testing is helpful because it allows audiologists to rule out hearing loss due to inner ear issues. The presence of OAEs indicates proper outer hair cell function, while its absence can suggest sensorineural or conductive hearing loss.
Otoacoustic emissions tests are non-invasive and don’t cause any discomfort. They are also quick and allow you to identify hearing loss early before symptoms become more obvious.
Speech-In-Noise Testing
Different Types of Hearing Tests: Finally, your audiologist may recommend speech-in-noise testing. This test evaluates your ability to follow conversations in noisy environments, a common issue for those who are hard of hearing.
Speech-in-noise tests are helpful because, unlike pure-tone audiometry, they reflect real-world situations. Sometimes conventional tests underestimate the degree to which hearing loss affects your life because they don’t take the entire picture into account (often measuring specific parts of the ear).
Speech-in-noise testing is helpful if you wear hearing aids. Audiologists use your feedback to fine-tune hearing devices and adjust them to meet your requirements.
Speech-in-noise tests occur in a quiet room.
Audiologists can adjust what’s called the “signal-to-noise ratio.” So for example, the main voice can be loud relative to the background, or vice versa. Adjusting this ratio allows the hearing health professional to determine the severity of your situational hearing loss, if any.
For more information on the types of hearing tests you may need, speak to our professionals.
Call 0113 8730444