Hearing Loss and Hearing Services at LSU Health Sciences Center
About
Hearing Loss
Hearing loss is among the most common
problems in our population, with
more than 10% of us suffering from
some sort of auditory impairment.
As we age, more hearing loss is
noted; however, about 1 in 1000 newborns
are deaf at birth and about 4 in
1000 have some lesser auditory problems.
The earlier we can identify this
hearing loss, the better we can
intervene and allow the child and
their family to learn language.
With early identification in mind,
Louisiana has a mandatory newborn
deafness screening program that
has helped to identify many more
of Louisiana's hearing impaired
children than ever before.
Children
of hearing families usually have
to learn language by ear and learn
to speak. Deaf Children of Deaf
Families
learn
language through signs and usually
choose not to speak. While there
is considerable controversy in the
field at large, LSU scientists and
clinicians have learned to respect
the choices families make for their
children and to offer services only
when requested. Services can range
from family support and vocational
counseling within Deaf Culture,
at one end, through hearing aids
and cochlear implants (a computerized
device implanted in the inner ear)
for access or return to the hearing
world.
Some years ago it was common to divide hearing loss into two types, conductive deafness and nerve deafness, with the former being medically treated and the latter managed with hearing aids (but presumably only marginally). Now, through scientific research and study, we have learned that there are at least 70 types of inner ear deafness that can occur, and few of them involve only the nerve fibers. The problems can involve the tiny hair cells (both inner and outer) inside the hearing organ (the cochlea and organ of Corti), in which case unique types of hearing aids that simply amplify faint sounds and not loud ones are available. These are not your father's hearing aids but rather highly sophisticated devices that, if properly programmed, can compensate for the loss of outer hair cells and bring almost normal hearing to the patient in all but the most difficult listening conditions. These aids can also be fit with directional microphones to cut through intrusive noise and allow the listener to focus on a conversation in a very noisy environment. In special cases a device called an Assistive Listening Device may bring the mouth of the speaker directly to the ear of the listener over long distances.
Hearing
loss caused by middle or outer ear
obstructions have been commonly
treated by otolaryngologists (Ear,
Nose, and Throat physicians and
surgeons) with medicine and/or surgery.
But now we also know of many medical
and surgical treatments for inner
ear problems as well, and the scope
of practice of otolaryngology has
expanded considerably. At present,
the otolaryngologist is the medical specialist most trained
to handle ear disease, and audiologists with Master or Doctorate
degrees are the professionals
who manage hearing loss non-medically
with hearing aids and advanced assessment
and fitting tools. These highly
skilled professionals work together
to serve their populations at the
peak level of efficiency.
About LSUHSC
and its services
Louisiana has had one of the world's
leading hearing research and clinical
services since 1967. The Kresge
Hearing Research Laboratory of the
South, part of LSUHSC's Department
of Otolaryngology, has been a leader
in the development and implementation
of physiological assessment of auditory
disorders, including Auditory Brainstem
Response, Electrocochleography,
Otoacoustic Emissions, and other
advanced tests of hearing function.
To this day we continue to follow
up on patients who are now in their
thirties who were diagnosed as deaf
in the 1970's at less than one month
of age.
Our laboratory scientists under Dr. Richard Bobbin have helped discover some of the chemical compounds that activate the ear, as well as some of those that shut it down. They have isolated and studied outer hair cells and the structural support cells that keep the ear working.
In
1990, the lab began a long and fruitful
collaboration with Dr. Bronya Keats
and her colleagues in the Department
of Genetics. The collaboration was
based initially on NIH funding for
the lab which in part supported
Kresge scientists, as well as Dr.
Keats and some of her colleagues.
As the decade neared its end, Dr.
Keats received a large award from
the Federal government to serve
the genetics needs of the Acadian
community. This Federal support
dovetailed with other funding that
allowed both research and service
programs to work hand-in-hand. In
supporting service to Acadian communities,
Dr. Keats made available auditory
screening programs with otoacoustic
emissions and other tests as part
of screening patients for visual
and retinal deficits as well, while
studying and serving patients with
Usher syndrome as well as those
with Friedreich ataxia. These two
genetic diseases are found in Louisiana
populations, and Dr. Keats and her
colleagues have been successful
in locating the mutations that cause
them.
The auditory system has yielded some of its most exciting secrets to genetic and molecular study in the past few years, and the LSU team, led by Dr. Keats, has been in the forefront not only of the discoveries but their rapid application to clinical practice. For example, in collaboration with NIH scientists and other colleagues around the world, we have participated in a study that identified a specific mutation of a Gap Junction Protein which leads to severe deafness. The place of the mutation on the gene differs with people of various ethnic extractions. Dr. Hood, in a series of NIH-supported studies, is complementing these findings by working on techniques to identify carriers by objective audiological tests alone.
We have also learned that objective and early identification of deafness leads to excellent management and language learning, whether families want their child to be raised in the hearing, Deaf, or both worlds. Knowledge is power, and suitable educational management and language learning follow correct diagnosis. LSU scientists have developed techniques for objectively differentiating types of deafness that would respond well to hearing aids versus types that would not respond to hearing aids or auditory verbal therapy (a problem called Auditory Neuropathy or Auditory Dys-synchrony). The management of such children requires the use of sign language and/or Cued Speech rather than depriving the child of visual input and asking the child to learn to learn by ear alone. However, cochlear implants have been shown to be remarkably successful in bringing such children into the hearing world if their families were so inclined.
The laboratory and some of its surgeons have helped LSU, in collaboration with the Eye and Ear Hospital, lead the way in the use of Cochlear Implants as a means for deaf people to learn language by ear. (For more information see www.kresgelab.org). With regard to cochlear implants, an area where Louisiana has been in the forefront since the mid-1980s, Dr. Charles Parkins, our most experienced surgeon, and his colleagues have contributed to the better understanding of electrical field dispersion and how cochlear implants stimulate residual nerve fibers inside the ear.
LSU's
cochlear Implant Program, under
the direction of Dr. Linda Hood,
has implanted more than 150 people;
a collaborative program with the
Eye and Ear Hospital, Tammy Crabtree
and the Joachim Hearing and Speech
Center, it focuses properly on the
use of Auditory Verbal Therapy and
speech use among the deaf after
the implant is in place. Among the
things we have learned is that the
use of visual languages must be
curtailed as much as possible after
implants are activated, and that
we must ask for flexibility as well
as accommodation from the educators
throughout our state who serve our
patients after they have been implanted.
In summary, we are entering a new age of identification, understanding, and care for hearing loss in our State. We have one of the country's finest resources as part of LSU Health Sciences Center, and we are here to serve you.
For
More Information
Information about
our services can be found at www.kresgelab.org.
If you have a hearing impaired child visit www.listen-up.org as an important unbiased resource and contact with other parents.
If
your child has something called
Auditory Neuropathy/Dys-synchrony,
visit our web site above and a parents
resource list at www.auditoryneuropathy@yahoo.com.
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