Central Auditory Processing Disorders (CAPD's)

by Judith W. Paton, M.A., Audiologist

Reproduced on NLDline with permission of the author

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 nones crisscross 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 condition 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).


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 treating 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.


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 recency of the problem in the testing). We are just beginning to confirm by brain wave studies, PET scans, autopsies. and other research that learning &abilities 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 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 3. 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

One can get an idea of an auditory problem even in a preschool child simply by watching for certain types of behavior:

1. greater tendency to ignore" a speaker when engrossed in something;

2. unusual sensitivity to or complaints about noise;

3. difficulty telling the direction from which the parent is calling;

4. tendency to confuse similar-sounding words;

5. 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. Complete cost ranges from $150-$300. Still testing may not be necessary if changes in the environment or education some 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:

1. explanations given you for the hearing or learning problem contradict you own common sense or knowledge of the problem;

2. You need more information to help distinguish an organic learning problem from an emotional one, for school or job placement or counseling purposes;

3. 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 CAPDs.

1.) Some speech sounds are distorted. When you talk to someone with a foreign accent you must make a series of mental adjustment 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 get 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.

2.) Background noise is too loud. When we strain to follow a conversation at a large party we arc 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?

3.) 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 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.


Working toward an "auditory favorable" classroom

 Problems with

Surface behavior 

 Tipoff behavior

 Possible adjustments

 Getting the sound in
  • too soft
  • sounds distorted
  • message not will separated from background sounds
  • Says "What?" a lot, even when had heard much of what was said
  • Talks or likes T.V. loud
  • Daydreams or acts uninterested and bored
  • Claims you said a different thing
  • Careless errors on exacting tasks
  • Work quality varies widely on same type of assignment
  • Misarticulates some sounds
1. Seat close to speaker, away from obvious noise sources.

2. Supplement with more intact senses (e.g. use handouts, manipulatives)

3. Refer to school nurse or M.D. to rule out peripheral problems, e.g., hearing loss, allergies, ear infections.

  • poor short term auditory memory
  • poor rote memory or habituation
  • sequencing problems
  • Ignores- oblivious to important sounds
  • Looks at others' work when shouldn't
  • Often interrupts with questions
  • Omits some steps in serial directions
  • better math concepts than math facts
  • likes background information, mnemonics
  • digit reversals, spoonerisms
1. Reduce or space directions.

2. "Capture" fleeting speech on tapes or handouts.

3. Teach logical systems, visualization,"story behind the facts," memory tricks.

4. Substitute manipulatives for repetitive drill like flash cards or recitation.

 Ascribing meaning
  • doesn't consider alternate meanings
  • can't access words
  • can't access scripts
  • words "don't paint a picture"
  • Works fine if kept in at recess or otherwise coerced
  • Obnoxiously inattentive (mainly older students) e.g., polishing nails during classroom discussion
  • Literal, feelings easily hurt
  • Can't infer
  • Asks many questions but proceeds with work if answered
  • "Silent"- evokes: "Why didn't you tell me?"
1. Teach abstract vocabulary, word roots, synonyms/antonyms.

2. Role play social scripts and other language pragmatics

3. Start others on task, answer extra questions individually

4. Show rather than explain

Linking with other brain centers
  • poor sound-symbol association
  • problems reauditorializing when reading
  • difficulty expressing ideas in writing


This section is undivided because no one has segmented the job for the student at this stage.

  • can't sound out unfamiliar words
  • spelling errors are phonetic
  • reading comprehension problems based on misread words, not lack of inference
  • dictated stories OK
1. Use Phonemic Synthesis tapes

2. Borrow exercises from field of Speed Reading

3. Use techniques from edukinesthetics, developmental therapy, or neuro-linguistic programming.


How to help

The good news is that reducing even some of these problems can lighten the load the child carries and free up energy to deal with the remaining ones. These are the main type of help we can offer:

1.) 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.

2.) Empowering the person to help with the problem. This can only be done through careful evaluation and diagnosis to find out 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.")

3.) 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 set 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

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 us out:

1.) 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.

2.) 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.

3.) Do you have 8 sliding fee scale ? (This is for people without private or public health coverage.)

4.) 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.

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.

About the author: Judith W. Paton, M.A., is is an audiologist in private practice in San Mateo, CA. For more information about the author write to: 136 North San Mateo Drive, Suite 101, San Mateo, CA 94401. PH: (650) 340-1280/343-7225.

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