Testing Your Child’s Hearing
The main purpose of a hearing test is to determine the degree, configuration and type of hearing loss. Without comprehensive testing, it is impossible to determine that a child hears normally across the range of frequencies necessary for understanding speech. Since speech consists of both low and high-pitched sounds, a hearing loss in one range can cause the child to misunderstand speech. Various tests can be used to determine the characteristics of your child’s hearing loss.
The results of the test are recorded on an audiogram, a graphic chart of hearing results. The physician determines whether medical or surgical treatment is required based on the audiometric findings and otologic examination. Should your child have a hearing loss which cannot be treated medically or surgically, an audiologist can provide amplification to assist your child in hearing sound. Hearing aids can be provided at any age.
What Is an Audiogram?
An audiogram is a picture of the softest sounds that your child can hear. Both the loudness and the pitch of a sound are shown on the audiogram. Very soft sounds are located at the top of the chart and very loud sounds are located at the bottom of the chart.
The loudness, also known as intensity, is measured in decibels (dB). Low pitched sounds, like a big drum, are located on the left side of the audiogram and high-pitched sounds, like a bird chirp, are located on the right side of the audiogram. Pitch or frequency is measured in Hertz (Hz). A loud low-pitched sound, like a foghorn, will be marked in the lower left corner of the audiogram and a soft high-pitched sound, like a mouse squeak, will be marked in the upper right corner of the audiogram. The softest sounds called hearing thresholds are marked on the audiogram as red O’s for the right ear and as blue X’s for the left ear.
The patterns formed by your child’s hearing thresholds are described as the degree and the configuration of your child’s hearing loss. The degree of hearing loss refers to the average amount of hearing loss for speech sounds. For children, a mild hearing loss ranges from 20 dB to 40 dB, moderate from 45 dB to 60 dB, severe from 65 dB to 85 dB, and a profound hearing loss at 90 dB hearing level or greater. The degree of hearing loss can be the same or different in each ear.
The slope or curve of the lines on the audiogram indicates the configuration of hearing loss. The configuration of the hearing loss could be flat where the hearing is about the same for all pitches. The hearing loss could be slightly worse in the high pitches and described as gradually sloping. It is more common for a hearing loss to be worse in the high frequencies than the low frequencies. Another shape is described as a cookie-bite when the hearing loss is worse in the mid frequencies than it is at the low and high frequencies.
The degree and configuration of the hearing loss indicate how well your child can hear without amplification. A child with a mild flat loss can hear normal conversation in quiet situations when close by. A child with a moderate sloping hearing loss will hear talking if it is louder than normal. A child with a severe hearing loss with a cookie bite shape will need the TV turned way up to be able to hear it. A child with a profound hearing loss will only be able to hear very loud environmental sounds like a siren.
Hearing Can Be Evaluated at Any Age
Hearing testing can be completed in children of any age using objective and behavioral audiologic test methods. Therefore, hearing testing should not be delayed.
Types of Pediatric Hearing Tests
Testing a child’s hearing can be very different from testing an adult’s hearing. Therefore, it is important that you have your child tested by an audiologist experienced in testing young children. The audiologists at The Hearing Center at Dallas Ear Institute have extensive experience testing children of all ages and developmental levels.
There are many modern methods that can accurately determine the hearing of a newborn, infant or child. The type of test used depends upon the child’s age and abilities. Behavioral hearing tests require that the child respond in some way (verbally, raising a hand, or through a listening game) to soft sounds produced by an audiometer. For a child too young to behaviorally respond or a difficult-to-test child, objective tests (otoacoustic emission measures and auditory brainstem response) can be used to estimate hearing without a response from the child.
Behavioral Hearing Tests
Visual Reinforcement Audiometry (VRA)
Beginning at about six months of age and into the 2-year-old range, behavioral hearing testing called visual reinforcement audiometry (VRA) can be used to determine if a child has a hearing loss. This test reinforces a baby’s head-turn response to test sounds using an animated toy. With this technique, sounds are presented through headphones or a loudspeaker. Young children are taught to turn toward an animated toy as reinforcement for every time they hear a sound.
Conditioned Play Audiometry (CPA)
Young children and preschoolers are tested with conditioned play audiometry (CPA). This method uses a game activity every time a sound is heard. One example is having the child drop a block in a bucket when a sound is heard. Sounds are usually presented through earphones and results are graphed on an audiogram.
Objective Hearing Tests
Auditory Brainstem Response (ABR)
Auditory brainstem response (ABR) is an objective test that does not require the child to behaviorally respond. Test signals such as brief clicks and tonebursts are sent to the child’s ears through earphones. Electrical responses produced by the cochlea in response to the test signals are recorded from electrodes on the head. The responses are averaged by the computer and displayed as a waveform. The child must be sleeping to record the ABR. The responses to the stimuli can provide an estimate of hearing sensitivity and information about the function of the auditory pathway to the level of the brainstem.
Otoacoustic Emissions (OAES)
Otoacoustic emission (OAE) testing involves sending sounds to the child’s ear with a small loudspeaker. A microphone records a “cochlear echo” known as an emission in response to test signals. This provides valuable information on hair cell function in the cochlea.
Tympanometry (Acoustic Immittance Testing)
Middle ear function can be assessed through tympanometry, which will help determine the presence of fluid behind the eardrum and help diagnose middle ear problems. A gentle puff of air is sent into the ear and the amount the eardrum moves in response to change in air pressure is recorded. If the eardrum does not move, for example, it could mean there is fluid behind the eardrum. The test is quick and painless.
Newborn Hearing Screening
Nothing is as precious as a newborn baby. Communicating with your baby is one of the most important things to consider. Babies first communicate their needs by crying. Your baby learns how to communicate in other ways depending upon his or her hearing acuity.
One of the most common problems at birth is hearing loss. Hearing loss occurs in 1 to 3 infants per 1000 births. About 3 babies in 100 who were cared for in the neonatal intensive care unit (NICU) have hearing loss. It is important to identify hearing loss as early as possible to minimize the impact on the development of speech, language, and learning.
The majority of newborns receive a hearing screening before discharge from the hospital. Two types of objective test methods are used to screen for hearing loss in newborns: otoacoustic emissions and the auditory brainstem response. These screening tests can detect 80 to 90% of infants with moderate degrees of hearing loss and greater. However, no screening test is perfect. Babies with mild hearing loss may pass the newborn hearing screening. The newborn hearing screening cannot identify children with late onset or progressive types of hearing loss.
Even when an infant passes a hearing screening in the hospital, it is important to monitor developmental milestones for hearing, language, and speech. If your child was born with visual, cognitive or motor disabilities, a comprehensive hearing evaluation should be performed to confirm your child’s hearing is completely normal.
Babies who are not born in the hospital or babies born at small hospitals may not have had a newborn screening. If you are unsure if your baby had a hearing screening or if your baby did not pass the screening, contact us at 972-566-7359 to schedule an appointment.
Early Identification of Hearing Loss
Every Moment Matters
The sooner a baby starts to listen to language in his or her environment, the sooner language, speech, and listening skills can develop. Hence, the earlier your child is tested, diagnosed and treated for any hearing loss, the greater their chances of achieving their personal best in speech and language skills.
The earlier hearing loss occurs in a child’s life, the more serious the effect on the child’s development if left untreated. Children with untreated hearing loss are likely to experience delayed language, speech development, communication and even cognitive skills. This in turn is linked to isolation, low self-esteem, learning difficulties and behavioral problems. However, the earlier the hearing loss is identified and treatment begun, the less serious the ultimate effects on the child’s development.
Detection of hearing loss in children should occur as early in life as possible. All newborns should be screened for hearing loss before 1 month of age. Ideally, infants born with hearing loss should be identified and confirmed by 3 months of age so that intervention programs, including the fitting of hearing aids, can begin. The first three years of life are critical to speech and language development. Unfortunately, while some children’s hearing losses are detected within the first year of life, many more children with hearing loss are not detected until they enter elementary school. For this reason, most hospitals screen newborns for hearing loss before the newborn leaves the hospital.
The audiologist and the physician when required evaluate a child with suspected hearing loss. The extent of the work-up varies greatly depending on the complexity of the problem. After all the evaluations are completed, a treatment plan is determined based upon the degree and configuration of the hearing loss. Long-term follow-up of children with hearing loss is usually required and other members of the health care team are frequently involved.