Download Hearing Problems in Pediatrics A Discussion of Hearing Problems in

Hearing Problems in Pediatrics
A Discussion of Hearing Problems in Children
Function of the Normal Ear
The ear is divided into three parts: an external ear, a middle ear and an inner ear. Each part performs an
important function in the process of hearing.
The external ear consists of an auricle and ear canal. These structures gather the sound and direct it
toward the eardrum membrane.
The middle ear chamber lies between the external and inner ear. This chamber is connected to the back
of the throat by the Eustachian tube which serves as a pressure equalizing valve. The middle ear consists
of an eardrum membrane and three small ear bones (ossicles): malleus (hammer), incus (anvil) and
stapes (stirrup). These structures transmit sound vibrations to the inner ear. In so doing they act as a
transformer, converting sound vibrations in the external ear canal into fluid waves in the inner ear.
The inner ear chamber contains the microscopic hearing nerve endings bathed in fluid. Fluid waves
stimulate the delicate nerve endings which in turn transmit sound energy to the brain where it is
interpreted.
Types of Hearing Impairment
The external and middle ear conduct and transform sound; the inner ear receives it. When there is some
difficulty in the external or middle ear a conductive hearing impairment occurs. When the trouble lies in
the inner ear, a sensori-neural or nerve hearing impairment is the result. Difficulty in both the middle
and inner ear results in a mixed impairment.
Conductive Impairment
A conductive impairment may result from blockage of the external ear canal, from a perforation (hole)
in the eardrum membrane, from middle ear infection, from fluid accumulation due to blockage of the
Eustachian tube, or from a congenital defect or disease of any of the three middle ear bones. This type
of impairment is usually correctable through surgery.
Fortunately the child with a conductive hearing impairment will never go deaf. He will always be able to
hear, either through ear surgery or by use of a properly fitted hearing aid.
Sensori-Neural Impairment
Sensori-neural impairment is the term used to describe hearing impairments which result from
disturbances or defects in the inner ear and nerve transmission. These impairments may be congenital
(present at birth), hereditary, or developmental, or a combination of these.
Virus Diseases
German measles contracted by a mother during the first three months of pregnancy may interfere with
inner ear development in the fetus. Occasionally other virus diseases are at fault. The viruses of measles
and mumps may cause a sensori-neual impairment after birth but this happens infrequently.
Problems at Birth
Jaundice occurring at or shortly after birth is capable of damaging the inner ear. This is most often due
to Rh incompatibility between the mother’s and the child’s blood. Fortunately this is uncommon. A
vaccine has been developed which may prevent this problem in the future.
A very difficult or complicated labor may result in inner ear damage at times.
Hereditary Impairment
Hereditary sensori-neural hearing impairment may be present at birth, or may develop later in life. Even
though there may be no hearing impairment in the parents, careful questioning often reveals some
more distant relative with a similar problem.
Treatment
There is no known medical treatment that will restore hearing in sensori-neural impairments. We must
rely on rehabilitation through use of a hearing aid and special training. Fortunately only one in a
hundred children with this type of impairment will show progression of the impairment over the course
of years. In cases of total deafness, a cochlear implant operation may be an option for the patient.
Cochlear implantation is done at specialized centers with a team of surgeons, audiologist, and speech
pathologists.
Hearing Impairment in One Ear
A hearing impairment that is confined to one ear deprives a person of the ability to distinguish the
direction of sound. He will also have difficulty hearing from the involved side in a noisy background.
These are minor problems to a young child.
When this impairment is conductive, surgery is usually possible to restore the hearing, giving a better
auditory balance when the loss becomes a problem, usually in the teens. When the impairment is sesorineural it is often possible when the child grows older to restore some of this balance through use of a
special hearing aid (CROS aid).
Rehabilitative Measure
A complete otologic examination by a competent ear specialist is necessary to determine what type of
hearing impairment is present, its probable cause and its treatment. At times it may be necessary to
obtain x-rays, a balance test or other laboratory tests to make this decision.
The treatment of choice may be remedial, preventive, medical, surgical or a combination of these. Each
child with impaired hearing should have the benefit of adequate auditory rehabilitation.
A well-rounded program of rehabilitation for a child with a hearing deficiency may include speech
reading, auditory training, speech conservation and improvement and instruction in the use of a hearing
aid. All aspects of the program do not necessarily apply to each individual with an impairment but each
can be helpful through some of these methods. The possibility of rehabilitative assistance should not be
overlooked; the benefits can be very great.
Hearing Aid Evaluation
Evaluation of the hearing in a young child may require several visits with the audiologist. It is import to
arrive at an accurate measurement of both the type and degree of impairment in order to select the
proper aid. An aid that is too powerful for a young child may irritate his ears and cause him to reject it.
On the other hand, if the aid is not strong enough, a child may receive little or no benefit from it and
object to wearing it.
It can be difficult to encourage children in regular classrooms to wear hearing aids, especially
adolescents. However, the learning experience is vital to help children reach their maximum potential in
adulthood. For these reasons, it is important in adulthood. For these reasons, it is important that
children wear their hearing aids in school.
Speech Reading
Speech reading is very important whatever the type or degree of impairment. This skill enables a person
with impaired hearing to understand conversation by attentively observing the speaker. All of us,
whether we have a hearing loss or not, employ the sense of sight as well as the sense of hearing in
ordinary conversation. We find it easier to comprehend if we can watch the speaker’s facial expressions,
lip movements and gestures. Just as the visually handicapped learns to use his sense of hearing to
compensate for his impaired sight, so the person with defective hearing must learn to use his eyes to
assist him in hearing. A study of the fundamentals of lip-reading or of speech reading, as it is called, will
make communication less of an effort and therefore more pleasant for both the speaker and the
listener.
Speech reading has its limitations. For example, when the distance between the speakers is great or
when the distance between the speakers is great or when there is faulty lighting or defective vision, one
may not always be able to see the speaker’s lips clearly enough to speech read adequately. Some
persons do not open their mouths very far when they speak and in consequence their lip movements
are very limited. Others have beards, hold their hands over their mouths or smoke as they talk, making
speech reading difficult if not impossible.
Because most sensori-neural hearing impairments involve primarily the higher frequencies, the child
must therefore rely on these visual clues to understand what is being said. It is the high-frequencies that
include consonant sounds or those sounds made with the lips, teeth or tongue. For instance, the words
“fit,” “sit,” and “bit” may sound the same but will look differently when pronounced by the speaker.
It is imperative that children receive preferential seating in the classroom (front and center) so as to gain
the most from visual cues. The teacher must always be informed when there is a hearing loss present,
either temporary or permanent. This way, she can plan academic programs to suit the child as well as
keep up with progress more effectively.
Profound Sensori-Neural Hearing Impairment
If you child’s hearing level is greater than 70dB he will not, in all likelihood, be able to attend classes
with normal hearing children, at least in the beginning. It will be difficult for him, but with help of a
hearing aid, training and speech reading and attention to speech correction, he may be able to progress
through schools for the hearing handicap to normal schools, even to college, to take his place in a
society with normal hearing people.
For those children who are not able to achieve understanding for speech, special schools are available to
train them in the manual form of communication (finger spelling) and to train them in specific trades.
The type of school a child attends depends upon his progression in communication.
The Future
Cochlear implantation can be used in your (pre-lingual) children who have not yet learned to speak, as
well as, older children who have lost their hearing after obtaining the ability to speak (post-lingual).
Generally, post-lingual children obtain the best result in terms of communication. Pre-lingual children
who undergo cochlear implantation do not achieve “normal” hearing the way the non-hearing impaired
patient understands it. However, even pre-lingual deaf children can achieve the ability to talk on the
phone and hear waving signals, such as car horns, door bells, etc. Regardless, cochlear implantation
requires a lot of post-generative rehabilitation / training and should not be considered an option lightly.