Children
What parents should know about hearing loss
Beyond the test booth
What parents should know about hearing loss
Diagnosis:
Depending on the age, health and developmental level of a child there are numerous tests that can take place to measure how a child hears. In most cases, the accurate diagnosis of hearing loss in young children requires a battery of tests.
BEHAVIORAL TESTING
All behavioral testing requires that the child in some way participate and cooperate for testing.
BEHAVIORAL OBSERVATION AUDIOMETRY (BOA)
This test involves observation of a young infant while a variety of speech and calibrated sounds are presented at different loudness levels and at different pitches. Sounds are either presented while they are wearing small earplugs (to test each ear separately) or while sounds are coming from a speaker near where they are being held or are seated. Sounds can also be presented with a small oscillator worn behind the ear. Most young infants typically display changes in sucking, facial expression, or breathing patterns in response to hearing sounds. In the hands of an experienced pediatric audiologist, valuable information can be obtained from this test procedure. However, it is recommended that when this is the only type of behavioral test that can be conducted, that hearing levels be confirmed with electrophysiological test measures (e.g. ABR or ASSR) This test can take place for infants from birth to 4-6 months; however, it may also be useful when testing children with developmental delays who are unable to perform using more complex behavior tests.
VISUAL REINFORCEMENT AUDIOMETRY (VRA)
Infants as young as four to seven months begin to look for sounds by turning their heads. When the child turns their head they are rewarded with an animated toy, flashing light, or cartoon loop on a video monitor. After several presentations, the child will learn that when there is a sound, that very interesting toy or television image will appear, so they look for it again.
The child is seated in a high char or sometimes in a parent’s lap. When the test is being presented, the child is distracted by the parent, caregiver or audiologist by looking at puppets, toys or picture books. The sounds are presents through a speaker or a headphone (depending on the age of the child). Once the child has learned the technique of looking for the toy/video when the sounds are presented, the audiologist will use this technique to determine how loud the sound (or voice) has to be in order for the child to hear.
PLAY AUDIOMETRY
A child will be asked to wear either headphones on or small earplugs in their ears and will need to listen to sounds at different loudness levels and at different pitches. The child is trained to respond each time he/she hears a sound by playing a game (i.e.: drop a block in a box). Usually children from the age of two to three can be taught to perform this task. As it requires patience (waiting to hear the sound) and a consistent response this method of testing may require some practice prior to the test session or may require multiple sessions. Children of this age will also typically be tested using speech audiometric procedures which may involve having the child point to pictures or repeat back words to measure the levels at which speech is heard, and how well it is understood.
STANDARD
A child will be asked to wear either headphones on or small earplugs in their ears and while the child wears a small oscillator worn behind the ear. They will need to listen to sounds at different loudness levels and at different pitches. The child will respond each time they hear a sound by raising their hand. Children who are entering kindergarten usually can be instructed to perform this test. Children of this age will also typically be tested using speech audiometric procedures which may involve having the child point to pictures or repeat back words to measure the levels at which speech is heard, and how well it is understood.
ELECTROPHYSIOLOGICAL TESTING
Electrophysiological testing does not require the child to pay attention or participate in testing. These tests can provide objective information about hearing and how sound travels through the ear to the brain. Some of the tests require the child to be very quiet and/or asleep. With very young infants (typically under 4 months of age), this can often be achieved naturally (without sedation). For infants and children over 4 months, for these tests, sedation is typically needed.
AUDITORY BRAINSTEM RESPONSE TEST (ABR) OR BRAINSTEM EVOKED RESPONSE TEST (BAER)
This test requires the child to be quiet or asleep and takes place by having the child wear both small soft earplugs in both ears and/or a small oscillator behind the ear as well as by having a few soft electrodes placed on their head. Sounds at different loudness levels and sometimes at several different pitches are presented into the earplugs and the electrodes measure the brain’s response to the sounds. A computer averages these responses and displays waveforms which are interpreted by the audiologist.
ASSR
This test procedure is very similar to the ABR test; however, this test allow for the presentation of both louder sounds and more frequencies than conventional ABR testing. It can be very helpful in determining more precise threshold levels for children with severe to profound hearing loss.
IMMITTANCE
This is a brief test that requires a small ear tip to be placed in the ear canal. One part of this test is Tympanometry which involves presented a small puff of air into the ear canal to measure the movement of the eardrum. The other part of this test involves presenting sounds into the ear to assess how the middle ear muscles work. This test is not a hearing test; however, provides information about how parts of the outer and middle ear are working.
OTOACOUSTIC EMISSIONS TESTING (OAE)
This is a very brief test that requires a child to be quiet for several minutes. The child has a small ear tip placed in the ear which briefly presents soft sounds into the ear. The probe is at the same time listening for sounds that the ear makes in response to hearing. This test, while not a hearing test, can provide information about how part of the cochlear is working.
