|
| |
What is Central Auditory Processing Disorder (CAPD)
and Testing for Auditory Processing Disorder
Contact Us
Complete
On-line AIT Checklist
This article was reprinted by permission from
Judith Paton,
M.A., Audiologist, San Mateo, CA.
What Is Audiology?
Audiology
is a medically-based field and the report will almost certainly go back
to your doctors for their input. You are also legally entitled to a copy
for your own uses if you sign a release. If words or ideas presented to
be clear to a doctor or educator are not clear to you, call the audiologist
for an explanation.
Beneath
the academic, emotional, and social facade of learning disabilities lies
a mild neurologic dysfunction, and it is not unusual for an LD person
to have subtle hearing problems. The hearing impairment is rarely a loss
of acuity in the ear itself, once the common ear infections of early childhood
have been corrected medically or outgrown, but instead is usually located
in the neural pathways of the brain which link the ear with the highest
intellectual centers (the central auditory nervous system.
Central Auditory Processing Disorders (CAPD's)
Not all the hearing is done in the ear. In fact, simply stated, the ear
merely brings in all the environmental sounds human beings can hear and
delivers them unseparated to the bottom of the brain in the brain stem
(just above the spinal cord). As the hearing nerves criss-cross up these
several inches the "sorting out" or processing
begins. Perhaps it begins because of a conscious decision of the intellect
("I hear my sister- I wonder what she's going to say') but the job
itself should be done by the lower level structures without our thinking
about it, like breathing. This processing includes such
operations as: focusing attention away from or dividing it between other
tasks (watching TV, taking a test, thinking about what happened this morning):
separating out "non-speech-like" sounds and inhibiting them
(sending down neural messages to reduce the activity of the nerves bringing
up the traffic noise or the dishwasher, for example); and locating in
space the voice you want to hear (perhaps focusing on the teacher in front
of you and ignoring two children talking to your left).
The
auditory system must convey the speech sounds (they are
not yet identified as words) without distortion up to the cortex of the
brain. Here the temporal lobe organizes them into words and the information
is routed to other centers of thought, action, sight, and so on.
For
all these jobs to be done we need several conditions. There must be enough
nerve fibers to share the work and no cell loss from such conditions as
lack of oxygen at birth or failure of development embryologically. Also,
the nerves must all transmit at normal speed, not slower in spots as when
the brain is swollen (this can happen with head injuries or strokes and,
some people believe, with certain allergies). The brain must be able to
produce proper amounts of chemical neurotransmitters for the nerves to
carry their messages (we see such failures in Parkinson's disease, and
they are suspected in Gilles de la Tourette syndrome and some forms of
autism).
Testing for Central Auditory Processing Disorders (CAPD's)
By
dividing the listening job into small components or tasks with special
manipulations of tones or speech, we can "map out" in a crude
way a hearing disorder in the central auditory pathways of the brain.
Such tests have been used for decades to help locate damage in a medical
caseload, and in the last ten years some tests have been adapted for children
school age and younger.
Establishing
a locale for an auditory problem has two main uses for
the learning disabled.
- First,
it points towards other helpful lines of inquiry. If there are brain
stem auditory problems, then looking for and
addressing
brain stem visual or vestibular problems could be considered. With cortical
level findings on auditory testing, therapists might
decide to test for and remediate phonemic synthesis or word-finding
problems.
- Second,
if the test pattern fits that of a CAPD, then a learning
problem is less likely to be misinterpreted as "laziness,"
poor parenting, or uncaring teachers.
Controversy About Central Auditory Processing Disorders (CAPD's)
The brain
seems to operate lawfully and reasonably predictably across disorders,
so that hearing acts the same whether the reduced cell count was caused
by a stroke or lack of oxygen (allowing for age and recentcy of the problem
in the testing). We are just beginning to confirm by brain wave studies,
PET scans, autopsies and other research, that learning disabilities and
central auditory processing problems
play by the same set of rules as the better researched disorders. This
is why you will hear the term "controversial" used for many
assessments of learning disabilities, including the audiologic ones.
Until
we know the answers, professionals and parents must deal with the learning
problems as best suits their own philosophy. One common point of view
is that even if a child (or adult) has CAPD-like hearing problems
and fails central auditory tests, it is not 100% proven
that he actually has an organic problem of this type, and it causes needless
worry and can even interfere with parent-child bonding to propose that
a child's brain might be imperfect in any way. The other view holds that
it is better to offer help on the theory that there may be a true
CAPD, since the help is not intrinsically harmful and can be
stopped it if proves ineffective, and that much harm is done by allowing
parents to think that they, the school or the child might be the cause
of the problem.
Deciding Whether to Test for Central Auditory Processing Disorders
(CAPD's)
One
can get an idea of an auditory problem even in a preschool
child simply by watching for certain types of behavior:
-
greater tendency to ignore a speaker when engrossed in something;
- unusual sensitivity to or complaints about noise;
- difficulty telling the direction from which the parent is calling;
- tendency to confuse similar-sounding words;
- confuses or forgets directions if several given in one sentence.
Some
of these items also appear with ordinary peripheral (in the ear) hearing
losses, so your doctor or school should do a regular hearing test first.
A pediatric audiologist can test infants and preschoolers.
If
the behavior you notice cannot be explained by a hearing loss, then there
is reason to suspect a CAPD. This testing is done by
an audiologist and is covered by the same insurance that pays for the
peripheral hearing test. CTtesting
may not be necessary if changes in the environment or education solve
the practical problems.
Here are Some Guidelines to Help with the Decision
If some of the above hearing problems
are noticed, you should consider formal audiologic testing if any of the
following is also true:
- explanations given you for the hearing or learning problem contradict you own
common sense or knowledge of the problem;
- You need more information to help distinguish an organic learning problem from
an emotional one, for school or job placement or counseling purposes;
-
progress in the present program is disappointing despite everyone's best efforts.
What Is It Like To Have An Auditory Processing Disorder?
We
have all experienced the problems that beset someone with this type of
hearing impairment. It just takes much more to push us into "auditory
overload", so that such problems are unlikely to occur on
a daily basis. Try recalling some of these situations and how they made
you feel, and then imagine how it would be if they went on and on and
you couldn't get away from them. The following are examples of some of
the common features of CAPD's.
-
Some speech sounds are distorted.
When you talk to someone with a foreign accent you must make a series
of mental adjustments to understand. These are usually based on
context (the nearest English word that would logically fit, given
the topic you are discussing) or on experience (such as how someone
of that nationality usually pronounces an "r" ). It gets
easier to decode after a few minutes' practice, but isn't it tiring?
And what if you were too young to have much vocabulary or general
information to help with the guesswork? We suspect that some children
with persistent speech articulation problems are saying the words
as they hear them. Imagine how school would be if you couldn't trust
your hearing-if you had to deal with different distortions with
different speakers but were still expected to follow a classroom
discussion.
- Background noise is too loud.
When we strain to follow a conversation at a large party we are experiencing
the effects of having too much extraneous sound delivered to our conscious
awareness. One way we survive is by pinpointing the location of the
voice we want to pay attention to and neurologically suppressing some
of the sounds coming in from other locations. Now imagine having poor
inhibitory mechanisms, as in ADD (Attention Deficit Disorder). If
that example seems extreme, picture yourself trying to balance your
checkbook with merely the TV going and two other people making occasional
remarks. We generally avoid such situations because we can't stay
on task, but make "silly" mistakes as the noise intrudes
on the visual-intellectual-motor parts of the operation. But how often
may a student say, "Stop that noise - I can't concentrate!"
or what freedom do most children have to go to a quiet office
to take a test?
-
Sound combinations (words) are not easily connected with their meanings
or uses.
This category covers many types of auditory dysfunctions
affecting the most "human" operations of communications,
learning, and empathy. In this population we find people who get complex
directions wrong, who miss spoken cues in social situations, and who
don't "speak up" for themselves, who don't infer or "read
between the lines." Think back to a time when someone was telling
you something elaborate, such as giving you directions to his house,
or explaining the computer or some other function at work. You may
have heard every word yet not been able to visualize the driving route,
or you may realize that by tomorrow you won't remember all the parts
of the work operation. You could say, "Draw me a map," or
"Let me go through this myself while you watch," using the
visual and haptic/motor systems of the brain to help you learn. But
what if the teacher in a class of 30 hasn't time for that? Or what
if you have poor language pragmatics so that it never occurs to you
that you could ask? Imagining yourself in a foreign culture will give
you some idea of what it means to lack easy social scripts (did you
learn the polite way of asking for the bathroom in your French classes?,
not get the joke (because you haven't picked up alternate word meanings
and slang in your travels), or to misunderstand the mood of the person
speaking because you didn't know the meaning of their tone of voice.
These are some of the ingredients to the social problems we see in
children who mean well but have trouble making and keeping friends.
Finally, to fully realize the load CAPD people carry, you need
to remember that these problems rarely occur in isolation.
A
child (or adult) who cannot suppress unwanted background sound also may not be able
to focus his eyes or track smoothly across the page for easy reading.
A sound distortion may be compounded by temporary hearing losses from
middle ear infections or allergic congestion. The combinations are endless.
Help For Central Auditory Processing Disorders (CAPD's)
The
good news is that reducing even some of these problems can lighten the
load the child (or adult) carries and free up energy to deal with the remaining ones.
These are the main types of help we can offer:
-
Taking over some of the hearing functions for the person.
If a student or worker makes errors on exacting tasks because he/she
is distracted by background noise we might move the desk away from
obvious noise sources (very talkative children or a computer printer),
or we could allow him/her to do the job later in another location.
Handouts, memos, manipulatives, Hands-on- learning, and "listening
buddies" are all examples of how deficient auditory information
can be supplemented. A corollary of this is to discover and use the
person's learning style rather than insist that he/she adapt to your
learning style. The chart accompanying this article describes one
system for discovering and reducing auditory processing problems.
-
Empowering the person to help with the problem.
This can only be done through careful evaluation and diagnosis to
find out what the problem is, so that we don't give naive advice like
"Pay attention," or "Don't interrupt with questions."
The problem can be broken down into manageable units and explained
to the CAPD person in language he can understand,
and the same is done with his strengths and learning style. Improvable
functions can be worked on by the appropriate specialist (e.g., a
taped Phonemic Synthesis program may be offered, memory devices taught,
or language pragmatics and social scripts practiced in speech therapy
groups), and the person then generalizes the strategies into daily
life.
When an accommodation is needed, students and workers must be respected
in their right to request and negotiate. A student should be able
to say, "Neat handwriting is hard for me physically," or
"Even tutoring hasn't helped a lot with my spelling. Would you
be willing to give me two separate grades on my written work for content
and mechanics?" Working people should know that Federal law requires
employers to make reasonable accommodations for physical handicaps
(e.g., a telephone amplifier or desk relocation), so long as the written
job description does not already require the abilities the employee
does not have (e.g., "Needs to communicate accurately by two-way
radio in machine area.")
-
Putting the person in the best physical condition for learning.
This avenue of help seems, in my experience, the least often explored.
Remember that Learning Disabilities is basically a physical disorder
with more than one component. A significant number of the learning
disabled have allergies, disturbances of balance, or sense of touch,
and problems with visual functions such as focusing, binocularity
(using the eyes together as a team). Perhaps allergy treatment can
reduce the swelling and congestion that further reduce hearing or
interfere with sleep and can bring the body under better voluntary
control to improve handwriting, coordination for sports, or ability
to sit still without constant movements to maintain balance. It may
be possible to share some costs between school and health insurance
so that, for example, reading therapy is speeded up by fitting the
child with reading glasses to lessen the effects of poor focusing
ability.
Choosing an Audiologist For Central Auditory Processing Disorders
(CAPD's)
As
with other professions where there is licensure, professional certification,
and a code of ethics, competence is not likely to be a concern. The main
issues in selection will be thoroughness, experience, and philosophy as
discussed earlier.
Four Main Questions Should Sort Audiologists Out:
-
Do you (or does someone on your staff) see many people with learning or central
auditory problems?
One such case every week or two over a year or two is enough to insure
an interest and expertise, I think.
-
How long is the appointment?
It takes an hour or more to test peripheral hearing and to check and
double-check the central auditory pathways; then
there has to be time to take a history, to explain the results clearly,
and to answer questions. Thus if the total time (some audiologists
might schedule more than one visit) is not 1 1/2- 2 hours, you are
probably not getting all that you need. Certainly a half-hour test
in a doctor's office will not cover the central auditory system,
but your doctor can refer you for more testing if you ask.
-
Do you have a sliding fee scale?
(This is for people without private or public health coverage.)
-
How might your report be useful?
Part of what you are paying for is a report that can advance your
efforts to solve the problem. You may need a statement that helps
qualify your child for school services or health insurance coverage,
or yourself for the right kind of help from the Department of Rehabilitation.
You may need puzzling or mislabeled behavior explained to a teacher
or psychologist. You might want suggestions for other types of follow-up.
The audiologist needs to know what your concerns are, and can tell
you which he can and cannot address.
| |
|
