Initial
General Examination
Although hearing loss is very common among adults, particularly those
over age 65, the condition is often under diagnosed in older people. Hearing
loss can greatly impact a person's quality of life. Therefore, if hearing loss
is suspected, it is important that the advice of a doctor specializing in
diseases and conditions of the ear, known as an otologist, otolaryngologist, or
ear, nose and throat doctor, is sought in order to make a definite medical
diagnosis. The ear specialist also will work in close cooperation with
audiologists, specialists in hearing disorders.
But at first, as you experience or suspect hearing, your primary physician
will perform an initially examination, as the first line of defense. Your ear may
be examined using an instrument called an auriscope, which is sometimes also
known as an otoscope. An auriscope is a small hand-held torch with a magnifying
glass used to examine the eardrum and the passageway that leads to it from the
outer ear.
An auriscope can be used to look for:
- Discharge –
fluid coming out of the ear.
- A bulging eardrum –
indicating that there is infected fluid in the middle ear.
- A retracted eardrum –
indicating uninfected fluid in the middle ear (glue ear).
- Perforated eardrum –
a hole in the eardrum, with or without signs of infection.
- Earwax or foreign bodies that might be blocking the ear.
Special Hearing
Tests
There are a variety of special tests available to accurately diagnose
the type and severity of hearing loss.
These include:
- Air Conduction, Conventional or
Standard Audiometry.
This test is commonly used to measure the hearing of adults and older
children. A range of test tones, from low to high frequency (perceived as
"pitch"), is transmitted through earphones placed on or in each ear,
and patients are asked to indicate with a hand raise, button push or verbal
response when you hear each sound. This testing determines the very softest
signals you can hear at each of the presented frequencies, and indicates
frequency regions in which hearing may be impaired. The louder the sounds must
be made to be heard, the greater the degree of hearing loss at that particular
frequency or frequencies. The frequencies tested are those important for
hearing and understanding speech and other environmental sounds.
- Bone Conduction.
If testing reveals a hearing loss, another type of headset, a bone
vibrator, is used to determine hearing by bone conduction in order to determine
the type of hearing loss. This device sends sounds directly to the inner ear,
bypassing the outer and middle ear. If the sounds are heard better by bone
conduction, the hearing loss is conductive in nature and is likely located in
the outer or middle ear. If the sounds are heard equally well with the
earphones and the bone vibrator, the hearing loss is sensorineural in nature. A
combination of conductive and sensorineural hearing loss also may be present;
this is called a mixed hearing loss.
- Word Recognition.
In addition to tests with tones, word recognition testing is usually
performed to evaluate the ability to discriminate differences between the
speech sounds of various words, and how clearly the words are heard. During
this test, you will be asked to listen to and repeat words. A test called the
spondee threshold test determines the level at which you can repeat at least
half of a list of familiar two-syllable words (spondees).
- Whispered Speech Test.
In a whispered speech test, the health professional will ask you to
cover the opening of one ear with your finger. The health professional will
stand 1 ft (0.3 m) to 2 ft (0.6 m) behind you and whisper a series of words.
You will repeat the words that you hear. If you cannot hear the words at a soft
whisper, the health professional will keep saying the words more loudly until
you can hear them. Each ear is tested separately.
- Acoustic Immittance.
These tests are used to assess the status of the middle ear and related
structures. A type of acoustic immittance test called, tympanometry, measures
the movement of the eardrum to see if it moves normally when pressure changes
are applied. Restricted eardrum movement could indicate a problem with the
eardrum or middle ear structures. Acoustic reflex testing, a method of
determining how the middle ear reacts to loud sounds also might be tested.
- Otoacoustic Emissions (OAEs).
OAEs are used to assess the function of the cochlea. OAEs are typically
present when hearing is normal or near normal, and are typically absent when
there is a problem in the cochlea. This test cannot distinguish between
conductive and sensorineural hearing loss.
- Auditory Brainstem Response
(ABR).
ABR is a procedure used to measure hearing sensitivity and determine if
the neural pathways within the brainstem are transmitting sound properly. This
test is used to rule out auditory-neurological problems. Brainwave activity in
the auditory centers of the brain is recorded in response to a series of clicks
or tones presented to each ear. During this procedure, electrodes are placed on
the head to detect the electrical response of the brains to sounds presented
while you rest or sleep. The electrodes do not cause pain or discomfort. This
test is also called brain stem auditory evoked response (BAER) testing or
auditory brain stem evoked potential (ABEP) testing.
- Vestibular Evoked Myogenic
Potential Testing.
This test is used to test one of the balance organs of the inner ear
for patients with unexplained dizziness/vertigo or certain types of hearing
loss. It requires the patient to turn and hold their head in fixed positions
while tones are played through earphones.
Hearing Test Results
Your hearing is considered normal if the following conditions are
satisfied:
- You are able to hear whispered speech
accurately.
- You can hear tones at equal loudness in
both ears.
- You are able to repeat 90% to 95% of the
words in a word recognition test.
- The microphone detects emissions from the
inner ear in otoacoustic emissions (OAE) testing.
- The values recorded on the graph for auditory brain stem response (ABR) testing show that the nerves in the brain responsible for hearing are working normally.
Your hearing is abnormal if:
- You are not able to hear the whispers
during a whispered speech test, or you are able to hear with one ear but
not with the other.
- You hear the tone more loudly in one ear
than in the other.
- You can only hear certain sounds at high
decibel levels.
- You can hear sounds but you cannot
understand words.
- No emissions are detected from the inner
ear in otoacoustic emissions (OAE) testing.
- The values recorded on the graph for auditory brain stem response (ABR) testing show that nerves in the brain responsible for hearing are not functioning normally.
Sound is described in terms of frequency and
intensity. Your hearing threshold is how loud the sound of a certain frequency
must be for you to hear it.
- Frequency, or pitch (whether a sound is low or high), is measured in vibrations per second, or hertz (Hz). The human ear can normally hear frequencies from a very low rumble of 16 Hz to a high-pitched whine of 20,000 Hz. The frequencies of normal conversations in a quiet place are 500 Hz to 2,000 Hz.
- Intensity, or loudness, is measured in decibels (dB). The normal range (threshold or lower limit) of hearing is 0 dB to 25 dB. Normal results show that you hear within these ranges in both ears.
Levels
of Hearing Impairment
The hearing threshold in decibels (dB) serves
as the official determinant for the level of the hearing impairment.
- Normal hearing – 0 – 25 dB.
- Mild decline (Difficulty
with faint or distant speech) – 26-40 dB.
- Moderate decline (Difficulty
with conversational speech) – 41-55 dB.
- Moderate to severe decline (Speech must be
loud; difficulty with group conversation) – 56-70 dB.
- Severe decline (Difficulty with loud
speech; understands only shouted or amplified speech) – 71-90 dB.
- Profound decline (May not understand amplified speech) – 91+ dB.
Factors to Affects the Test
There are several factors which might affect
the test results and show the unexpected state of hearing. Note these factors
and do your best to avoid their influence (as possible) before you make the
test appointment:
- Being unable to cooperate, follow directions, and understand speech well enough to respond during most tests. It may be difficult to conduct hearing tests on young children or on people who have physical or mental disabilities.
- Difficulty speaking or understanding the language of the tester.
- A recent cold or ear infection.
- Being around loud noises within 16 hours before the test.
Sources
and Additional Information:
