Children can be tested at any age. The methods used are dependent upon the developmental age of the child. Infants and toddlers are evaluated using six primary methods. None of the methods are painful and many are quite fun for the child. At Eastside Audiology, two highly experienced audiologists are present during the evaluation to confirm whether a response is present or to keep the child quiet or distracted while waiting for a sound presentation.
Otoacoustic Emissions (OAEs)
An Otoacoustic emission is an echo-type response that your ear naturally produces in response to sound. Using specialized equipment, we are able to measure this response when the baby is quiet. An otoacoustic emission is not tinnitus (ringing in the ear). This sound is not audible to the human ear. Sound is sent into the ear canal through a probe (small, thin medical instrument with a rubber tip) that sends and records sound. The ear’s response to the sound is measured. If an emission is present, this suggests that the child’s inner ear is normal or does not have more than a mild hearing loss. This test takes only a few minutes.
Auditory Brainstem Response (ABR/AER)
ABR records how well sound signals travel along the hearing nerve to the brain. It helps predict the child’s ability to hear. During this test the child may be sleeping or sedated. Electrodes on sticky pads are placed behind the child’s ears and on the head. Sound is presented to the ear through earphones and the electrodes record how the brain responds to the different sounds. This test takes about 30 – 60 minutes and is often performed in the neonatal ICU on high risk infants.
Behavioral observation audiometry assesses hearing acuity by observing the baby’s natural responses to sound. A behavioral observation assessment is conducted in a sound booth by a pediatric audiologist specially trained to detect bodily reactions to sound, such as body movement, eye widening, eye opening or change in sucking rate. This procedure is appropriate for children from birth through 6 months of age. The infant is observed for changes in behavior after the presentation of sound. This screening test provides information about the age appropriateness of an infant’s response to sound and can rule out significant hearing loss.
Visual Reinforcement Audiometry (VRA)
Once the child is around six months of age, the preferred method of testing is VRA. This test takes place in a sound-treated room and takes advantage of your child’s natural reflex to turn toward a sound. Your child will sit on your lap or in a chair between two calibrated loudspeakers or using earphones. When a sound such as a tone, speech, or music is presented, your child’s eye-shift or head-turn response toward the sound source is rewarded by activation of a lighted mechanical toy or a video screen mounted near the loudspeaker or on the side the sound was presented. Your child’s attention is then distracted back to the midline so that additional sounds can be presented. Once the child can perform the tasks necessary for VRA, we now begin to be able to measure the softest level a child can hear a sound.
As the child nears 2.5 – 3 years of age and is able to follow directions, the preferred method of testing is Play Audiometry in a sound booth. With this method, the child must be able to “wait” and “listen”. The child is taught to perform a play activity whenever they hear a sound. Activities might include putting a block in a bucket, placing a peg in a hole, etc. In addition, the child’s ability to understand speech can be evaluated by having the child identify pictures, objects or body parts.
Acoustic Immittance Testing
There are two basic types of acoustic immittance tests: tympanometry and acoustic reflex testing. These tests take only a few minutes and can be done on all ages.
Tympanometry evaluates middle ear function. It determines if the eardrum is moving appropriately as well as middle ear pressure. The test is performed by placing a soft probe into the ear canal. The instrument gently pushes air in and pulls air out of the ear canal. The changes in air pressure move the eardrum. The movement of the eardrum is measured.
Acoustic Reflex testing evaluates whether the Stapedius muscle in the middle ear responds to sound normally. As with tympanometry, a probe is placed into the ear canal. Sound is sent into the ear canal. The response to sound of the Stapedius muscle in the middle ear is measured.