by Susie Loraine, M.A., CCC-SLP
Hearing loss directly impacts a child's ability to communicate. Children develop
language and speech by hearing and imitating sounds in their environment; therefore,
a child that cannot hear all the sounds in his/her environment has difficulty understanding,
communicating, and learning about the world.
Causes of hearing loss vary from genetics, to infection, to injury. Children may
be born with hearing loss (congenital) or acquire the loss during infancy or childhood.
An audiologist (hearing specialist) or otolaryngologist (Ear, Nose, and Throat
Doctor) can help determine the significance of a child's hearing loss and any treatments
available that would benefit the child.
How We Hear
Sound waves travel from the source of the sound, such as a speaker, to the outer
ear. The air continues through the ear canal to the eardrum and causes it to vibrate.
The vibration of the eardrum triggers the bones of the middle ear—the malleus, incus,
and stapes—to move up and down; this movement creates waves in the fluid of the
inner ear, or cochlea. Tiny hair cells bend in the cochlea and stimulate the auditory
nerve which transmits the auditory information to the brain. A breakdown in this
system results in a hearing loss.
Types of Hearing Loss
When a child receives a diagnosis of hearing loss, the audiologist determines the
type and severity of loss. Hearing losses can be conductive, sensorineural, or mixed.
Severity ranges from mild to profound.
Conductive hearing loss happens when the auditory signal
breaks down at the outer or middle ear. This may be due to temporary conditions
such as fluid build up in the middle ear, ear infections such as Otitis Media, or
wax build up in the ear canal. Other children may have malformations of the ear
or ear canal that cause breakdown of the auditory signal. Medication or surgical
interventions can often treat and remediate conductive hearing loss.
Sensorineural hearing loss results from damage or malformation
of the inner ear or cochlea. This type of hearing loss is typically permanent and
often medical or surgical treatment cannot remediate the issue. Children with sensorineural
hearing loss often can benefit from wearing amplification systems such as hearing
aids or cochlear implants that can amplify the auditory signal or bypass the damaged
Mixed hearing loss consists of some combination of conductive
and sensorineural components of hearing loss.
Severity of Hearing Loss
To determine severity of hearing loss, audiologists measure a child's detection
of sound at a variety of different pitches and loudness levels. They refer to pitch
as "frequency" and loudness level as "intensity." The audiologist creates a graph
called an "audiogram" that shows the severity and shape of the child's hearing loss—the
loudness levels at each frequency the child needs to hear. Hearing loss can be mild,
moderate, severe, profound, or a combination of these.
Mild Hearing Loss—A child with a mild hearing loss may
have difficulty hearing soft speech or conversational speech when there is background
noise, such as in a restaurant.
Moderate Hearing Loss—A child with a moderate hearing
loss may have trouble hearing normal conversational speech.
Severe Hearing Loss—A child with a severe hearing loss
may have difficulty hearing loud speech and environmental sounds, such as a vacuum
Profound Hearing Loss—A child with a profound hearing
loss may not be able to hear loud speech or louder environmental sounds, such as
a dog barking, or even a lawn mower running, without some type of amplification.
Looking at the Audiogram
After testing your child's hearing, the audiologist graphs the frequencies and intensities
that your child can hear. Audiologists refer to this graph as an audiogram. The
lines on the graph create a "shape" of the hearing loss. The shape may be flat,
sloping, or create a curve called a "cookie bite." A flat shape means that a child
hears at about the same intensity level across all frequencies. A sloping shape
describes a need for more intensity (loudness) as sound moves across the different
frequencies. For example, a child may demonstrate a mild hearing loss in the low
frequencies, sloping to severe in the higher frequencies. Finally, the "cookie bite"
shape refers to a hearing loss that is milder in the low and high frequencies, with
a more significant loss in the middle frequencies.
Treatment of Hearing Loss
Regardless of type and severity, professionals (audiologists or otolaryngologists)
are available to help manage or treat a child's hearing loss. Amplification systems,
such as hearing aids or cochlear implants, and other medical or surgical treatments
may help increase a child's hearing ability. Hearing is directly related to development
of language, speech, reading, and writing, so parents and other professionals who
suspect a hearing loss should seek further testing and treatment immediately.