Do you suspect you have hearing loss? How can you be sure?
Hearing loss can affect anyone and often progresses so gradually, it can be difficult to notice until you experience symptoms. Hearing
loss has far-reaching effects on your health, so getting a baseline hearing test and annual follow-up tests can help you catch it early.
The purpose of a test for hearing loss is to determine not only if you have a hearing loss, but how mild or severe it is. A thorough
hearing test can also help define the type of hearing loss you have: conductive, sensorineural or mixed and whether it will respond
best to medical treatment, hearing aids, cochlear implants, or bone anchored hearing systems.
Audiology evaluations consist of a series of tests used to determine whether a hearing loss exists and, if so, measure its type, degree
and configuration. An audiologist will assess the results of each individual test in order to develop a treatment plan geared toward
your unique hearing loss.
Who Should Be Given An Audiology Evaluation?
An Audiology (or hearing) evaluation can benefit patients of all ages, even those who do not exhibit signs of hearing loss. An audiology
evaluation should be the first course of action for anybody who even suspects a hearing loss. The sooner a diagnosis of hearing loss
is made, the more successful treatment will be. Early detection means more options for the patient.
Many physicians urge making audiology evaluations a routine part of your overall health care, much like regular vision exams and
dental check-ups. They are quick, painless and provide immediate results.
What Does Diagnostic Testing Entail?
A comprehensive audiology evaluation consists of a series of individual diagnostic tests that measure different aspects of your hearing. Following a physical examination and a review of your hearing health medical history, you will be given hearing tests.
A Hearing Health Medical History
When you visit a hearing healthcare professional, their first step will be to get to know your personal hearing health and medical
history and find out what concerns you have. There are many potential causes of hearing loss, so the history helps determine if you
could have anything inherited or genetic in your family. Medical conditions like allergies, head colds, ear infections and even impacted
earwax (cerumen) can also contribute to hearing loss. Also, the hearing health practitioner might ask if you’ve experienced any trauma
to the head or ear structures recently. Any kind of injury to the cranial area can result in temporary or permanent hearing damage.
Your hearing healthcare professional may also ask about your exposure to loud noises or if you work in a loud environment. Noise
induced hearing loss is very common in our sound-filled world.
Finally, your hearing health professional might want to discuss the symptoms you are experiencing and how they are affecting your
daily life. They will want to understand your lifestyle and the types of work, hobbies and social situations that are important to you.
Keep in mind that hearing loss can be exhausting, so even problems like fatigue might be related.
After your hearing health medical history is complete, the hearing test can begin.
The Hearing Tests
Hearing tests are painless and non-invasive. Most occur in a quiet, sound-treated room (booth) or enclosure designed to keep out any other noises which might affect your hearing exam scores, such as the heater, air conditioner or office environment. You will be asked to wear headphones or soft earplugs with wires connected to an instrument called an audiometer that is used to conduct the test. The room may also be equipped with specially-placed speakers used for testing infants, small children or people who need to be tested while wearing hearing aids or cochlear implants.
Pure Tone Testing
Pure tone testing (also known as pure tone audiometry) uses air conduction to measure your ability to hear sounds of various pitches and volumes. Wearing headphones, you will be asked to identify a series of tones by raising a hand, pressing a button, or responding verbally. The results are charted on an audiogram, a graph that shows the type, degree and configuration of your hearing loss by comparing pitch (frequency) with loudness (intensity). The pattern recorded will help your audiologist determine your hearing threshold.
Bone Conduction Testing
Bone conduction testing is another type of pure tone test that measures the inner ear’s response to sound. If there is damage or a
blockage in the outer or middle ear, bone conduction audiometry testing may be used. Instead of sending the tones through the ear,
this type of testing is able to bypass the outer and middle ear and send the tone directly to the inner ear. A small vibrator is placed
behind the ear. The device sends out a vibration that passes through the skull bone to reach the inner ear.
If the results of this test are different than the air conduction test, your audiologist can use this information to determine whether you
have a conductive or sensorineural hearing loss. Bone conduction testing is often used in place of air conduction testing when an
obstruction in the outer or middle ears is present.
Speech Testing
Speech (or word recognition) testing is used to measure your speech reception threshold (SRT), or the faintest speech you can understand 50 percent of the time. This is compared with your pure tone test results to confirm the diagnosis. In addition, your ability to separate speech from background noise will be recorded. Speech testing may be administered in either a quiet or noisy environment; results are recorded on the audiogram for easy visual reference.
Tympanometry
Tympanometry is a test of the middle ear used to detect fluid, wax build-up, eardrum perforations and tumours. It measures movement of the eardrum in response to air pressure; the results are recorded on a chart called a tympanogram.
Acoustic Reflex Testing
The acoustic reflex test measures involuntary muscle contractions of the middle ear, and is used to determine the location of your hearing problem (the ossicles, cochlea, auditory nerve, etc.) as well as the type of hearing loss.
Auditory Brainstem Response (ABR)
Auditory brainstem response testing is used to determine whether a specific type of hearing loss – sensorineural – exists. It is also frequently used to screen new-borns for hearing problems. In an ABR test, electrodes are attached to your head, scalp or earlobes, and you are given headphones to wear. Your brainwave activity is measured in response to sounds of varying intensities.
Otoacoustic Emissions (OAEs)
Otoacoustic emissions (OAEs) are sounds generated by vibrations of the hair cells in the cochlea of the inner ear. OAE testing utilizes
a tiny probe fitted with a microphone and speaker that is used to stimulate the cochlea and measure its response. Individuals with
normal hearing will produce emissions; when a hearing loss exceeds 25-30 decibels, no sound will be produced.
This test helps determine whether there is a blockage in the ear canal, excess fluid in the middle ear or damage to the hair cells of
the cochlea. OAE testing is often included in new born hearing screening programs.
Hearing Tests For Children
New-Born Hearing Screenings
A new born hearing screening is mandated. There are two types of new born hearing screenings, both are painless and can be done while the baby sleeps:
- Otoacoustic Emission (OAE) Screening: This test records tiny sounds that the inner ear makes in response to clicks or chirps that are delivered through a small, flexible plug placed in the infant's ear. The screening is done on each ear and a passing result confirms that the infant’s inner ears are receiving sounds.
- Automated Auditory Brainstem Response (ABR): This test records activity of the auditory nerve in response to clicks or chirps delivered through a small, flexible plug placed in the infant’s ear. This screening is a more complete test of the auditory system, and it requires small electrodes to be taped to the baby's scalp. The screening is again done for each ear and a passing result confirms that the infant’s brain is receiving sounds.
A significant number of infants fail their first hearing screening due to fluid that may still be present in the ear canal right after birth. If your infant doesn't pass the initial hearing screening, schedule a follow-up screening with a paediatric audiologist within a couple of weeks. The majority of infants will pass the second screening quite easily. For those who do not pass the second new-born screening, a diagnostic hearing test from your paediatric audiologist will investigate further.
Hearing Testing For Infants And Young Children
Visual Reinforcement Audiometry
Paediatric audiologists can test infants as young as six months of age behaviourally in a sound-treated booth using a test called
visual reinforcement audiometry (VRA). VRA takes advantage of an infant’s reflexive head turn toward sound. In this test, a parent
will hold their child on their lap while they sit on a chair in the centre of the sound booth. The audiologist will play sounds or talk
through speakers that are oriented to the left and right of the child.
When the child hears the sound and looks toward it, he or she is rewarded with a visual reinforcement toy like a flashing light or
dancing bear. The infant will usually stay engaged long enough for the audiologist to get a good indication of hearing ability for at
least the better hearing ear.
The visually-appealing toys lose their ability to hold the child’s attention once they are toddlers. Around the age of two, social praise
will work for behavioural testing.
Play Audiometry
A paediatric audiologist will use a method of testing called play audiometry for toddlers and preschool children. It's a hearing test that
is made into a game for toddlers. The parent or assistant will sit on the floor in the booth with the child and train them to respond to
any sound they hear by doing a certain task, like putting a block in a bucket.
When the child correctly responds to a sound, the parent or assistant sitting with them will cheer with enthusiasm. Like the visual
reinforcement described above, this age-appropriate social reinforcement will typically keep the child engaged long enough for the
audiologist to get a good indication of hearing ability at least for the better hearing ear. If the toddler will wear earphones, ear-specific
information can be obtained.
Once a child is school-aged, he or she can usually sit still, remain quiet and raise a hand in response to speech and tone stimuli in
the sound booth. At this point, the child can easily wear headphones for ear-specific measurements and sit still for tympanometry
and acoustic reflex tests, as described above for adult hearing tests.