Wednesday, October 20, 2010

Interview with Dorothy Kelly: Central Auditory Processing Disorder and Speech

White noise image
RB: So, would it be fair to say that there are two categories of CAPD: developmental and acquired?
DK: Yes. However, I believe that the term Central Auditory Processing Disorder is too amorphous. Perhaps we should have several categories of the disorder such as Central Auditory Processing Impairment, Central Auditory Processing Disorder, and Central Auditory Processing Delay, especially where the CAP is secondary to another disorder. I also think that we should have a term called Specific Central Auditory Processing Disorder to describe CAPD when it exists alone. CAPD exists in secondary form in the vast majority of cases. I think that is one of the main reasons that the incidence estimates we have are probably underestimated. In the school setting, for example, CAPD is frequently applied to an academic school setting, which does not deal with those terms. In the school, the primary diagnosis would be an educational diagnosis such as Attention Deficit Disorder, Learning Disability, and so forth. So, the diagnosis of CAPD may be missed because all symptoms are lumped together under one disorder.
 
RB: I understand you deal with five skill areas in CAPD. Could you describe those skill areas?
DK: I have been working on CAPD since about 1974. My first years in practice were spent as a teacher of the deaf. My first group of students was a group of Rubella children that first entered the school system in the early 1970s. It was apparent to me at that time there were kids with very similar audiograms that had very different uses of residual hearing and there appeared to be a mismatch between hearing and perception. I came across a wonderful book (Auditory Perceptual Disorders and Remediation; 1974, Springfield, IL: Charles C. Thomas) by Bernice Heasley. Heasley identified fourteen areas of processing skills. As I studied these fourteen areas, I began thinking of five key areas that impact on social and academic performance and that is how I developed my five skill areas.
 
The first area I would mention is AUDITORY MEMORY. Auditory memory is often misunderstood and misdiagnosed, especially in schools. We tend to think of it as a generic skill involving repeating five numbers or five letters, or repeating a direction. If they repeat well, we tend to think that they have a good memory. Auditory memory if far more complex than that. It involves immediate as well as deferred memory. It also involves a variety of units. For example, a child may have good auditory memory for sentences, but not for numbers. We also tend to think that if a child has a good auditory memory, then the child should be able to carry out a direction. Carrying out a task involves far more than just rote recall of information. It involves an interpretation as well as an ability to carry out the direction. So, when we give a direction and ask the child to repeat the direction, we tend to assume that the child can carry out the task simply because the direction was repeated correctly. We know many children will be able to repeat a direction, but may have other programming problems (e.g., executive disfunction) that will inhibit or prevent them from actually carrying out the task. 
 
The second skill area is AUDITORY DISCRIMINATION. This is also an area that is underestimated in terms of its importance in the classroom. It impacts on following directions as well as spelling, reading, writing, and phonology skills. It is my belief that an auditory discrimination test should be a part of every reading program in schools. I feel that poor auditory discrimination is often a key factor when a child is not reading on target. There is a hierarchy involved in addressing auditory discrimination skills in therapy. Paula Tallal's work in the neurophysiological aspects of timing give us a lot of information on how to conceptualize a hierarchy for auditory discrimination tasks within a program. 
 
The third area is AUDITORY FIGURE-GROUND, which involves background noise. We know that auditory figure-ground in a normally developing child doesn't really mature until about age eight. If we have very noisy, unstructured, open classrooms in kindergarten through third grade, we may be asking a child to do more than he is capable of doing. Planning a program of intervention for the child with poor auditory figure-ground skills should start with building a tolerance for a variety of types and levels of noise and then having the child perform harder and harder tasks in those noises. We could begin with noise similar to that produced by an air-conditioner (white noise) and progress to a middle-ground type of noise that varies a little in frequency and volume but repeats a pattern, like the noise rain makes when falling or a dish-washer makes, and finally we could work with a cafeteria-type noise, noisy playground-type noise or the noisy classroom type noise, which is the most difficult type of noise to tolerate. Another factor that is not really auditory figure-ground, but is related to it is reverberation. We know that children don't do well perceiving speech within reverberant environments until as late as age thirteen. So, classroom acoustics is certainly something that we should be aware of and fine tune as far as possible. 
 
The fourth skill area, AUDITORY COHESION, is a higher order linguistic processing skill. It relates to such skills as complicated conversations as well as understanding jokes, riddles, inferences, and abstractions. It also impacts the child's ability to do note-taking. 
 
AUDITORY ATTENTION, the fifth skill area is the key skill. We come into the world with some ability to auditorily attend. We see in very young infants momentary attention to auditory stimuli. The auditory attention skill grows with maturation in the child. If there is delay in development of auditory attention, the everything else for the child is at risk in terms of performance in the classroom. Auditory attention is the glue that holds all the other auditory processing skills together. The skill areas are interrelated and hierarchial in nature. A child with CAPD may have any combination of difficulties to varying degrees of severity.

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