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| At What Age Can a Child Be Tested for APD? |
| By Jay R. Lucker, Ed.D., CCC-A/SLP, FAAA |
| Posted by Janis |
0000-00-00 |
Index
» By Jay R. Lucker, E...
One question that is often asked relative to auditory processing disorders (APD) is “At what age can a child be tested for APD?” Although one limitation of age is the child’s abilities and maturity to handle certain tasks that we use in assessing APD, the best answer to this question relates to the specific approach to APD the professional takes in doing the assessment.
One approach to APD and probably one of the most often applied approaches that audiologists take is related to the neurophysiology of the central auditory pathways. From the perspective of this neurophysiological approach, the goal of the APD assessment can be summarized as finding where in the central auditory pathways there is a breakdown that is causing the child to have a problem processing auditory information. Once this breakdown is found, the approach suggests looking for a possible physiological reason for the breakdown and treating the physiological disorder or ruling out a physiological cause and stating that the problem is due to a lack of normal maturation of the central auditory system.
If a professional takes this neurophysiological approach, then, APD could be defined only as a problem when the breakdown is not due to a neuromaturational factor. Additionally, the neuromaturation of the central auditory pathways continues from birth until the system reaches what can be referred to as adult functional status, around early adolescence (Chermak and Musiek, 1997). Therefore, one could state that APD testing to diagnose an APD disorder cannot be accomplished until you can rule out neuromaturational deficits, so we must wait until the child is 12 years of age.
Most professionals would not agree to wait that long. Even those taking a neurophysiological approach would rather say that it is worthwhile to test the maturation of the central auditory system in younger children. However, they may conclude that a child found to fail APD testing would have a developmental disorder, a lack of normal maturation of the central auditory pathways. Applying this approach the professional may they suggest to bring the child back for follow-up testing so that we can see if the central auditory pathways are maturing as reflected in test results moving more towards age level norms. Then, if over time the test results either remain poor or regress and show a greater gap between chronological age and test results, the professional may request more in-depth testing to rule out specific neurophysiological deficits in the central auditory system. Treatment or intervention would relate to making listening as easy as possible for the child until the central auditory system matures to a level that it can handle the normal load (Bellis, 1996).
The idea that there are age norms for the tests used in assessing APD indicates a second approach that is somewhat in line with the first, but does not specifically focus on the neurophysiology of the central auditory system. This approach may be called the age norm or test battery approach. In this approach, the APD test battery is administered and the child is said to have APD if he or she fails APD tests falling significantly below age level norms. The specifics of how “below age level norms” is defined may vary from professional to professional with some using age levels, some using standard scores, some using percentiles, and some using standard deviations. However, regardless of what the professional chooses to use, from this approach the child is said to have APD if tests in the battery are failed.
One limitation within this approach relates to the age norms available for the tests used in the APD battery chosen. For many audiologists, for example, they may choose tests that only provide age norms down to 7 years old. Thus, they would state that you cannot test a child below the age of 7 years. Others may feel that age norms exist below the age of 7, but they question the reliability of these younger norms in identifying abnormal auditory processing. That is, they define failing APD tests as an indication of abnormal auditory processing in the child, and the test battery approach focuses on identifying if the child does or does not have APD based on failing the APD tests in the battery.
Yet, there are many tests of auditory processing that have norms for children down to 4 and 5 years of age. As such, one could approach APD assessment from a test battery point of view stating that the youngest age a child can be tested is (for example) 5 years of age because there are tests the professional can perform in the APD battery that has norms for children of that age level. But, the focus of the test battery approach is merely to identify if the child passes or fails the tests and, based on the specific tests that were failed, to state that the child has APD problems in the areas of failure.
The third approach discussed in this paper is a more natural approach to APD looking at auditory processing within the normal spectrum of normal development. That is, all children who receive auditory information through their ears (i.e., have some degree of hearing) have to learn to use that information from the time they are born. Research has shown what some normal behaviors are that infants through the aged population reveal in response to auditory signals regardless of what the signals represent. For example, audiologists often look for a head turning, searching or localization response from a child 6 months of age when the infant hears a sound in the environment after not hearing anything else. Audiologists use this head turning to indicate the child’s awareness of tones of different pitches, speech, music and other sounds when performing what is called a pediatric audiological evaluation. Yet, what audiologists fail to recognize is that the head turning is a behavior in response to the presence of a stimuli. From the field of behavioral psychology, we can state that a response to a stimulus only occurs if the person has processed the stimulus. Therefore, we can obtain some information about auditory processing by noting a child’s behaviors to specific, controlled auditory messages comparing the behaviors to developmental norms. As such, auditory processing can be assessed to some degree in an infant, as in this example, 6 months of age.
Is there support for this naturalistic approach? Definitely, as Emmy would say on Dragon Tails! There is a body of knowledge about infant auditory perception in the area of speech perception and one can read about this research in any basic textbook on speech perception, acoustic phonetics, or normal speech and language development in children (starting at infancy). To summarize this research, the findings have demonstrated that as early as a few weeks to a few months of age, infants are discriminating speech sounds (what we call phonemes) and doing so on predictable, categorical dimensions. For example, an infant will change behavior when the child processes a change in auditory stimuli indicating that the child has discriminated there is a change. As such, if an infant were in a test booth and heard a series of “Pah” over and over again, there would be an initial recognition that the infant heard the “Pah” and then that behavior would go away (extinguish). If, after a time, the “Pah” series changed to “Bah,” the infant would respond to the change. Thus, as early as 6 months of age an infant is processing the presence vs. absence of sound (no sound to suddenly hearing “Pah”), processing the fact that there is no change in the speech message so no need to respond to this sound (extinction of the behavior), and then discriminate a change from the phoneme /p/ to the phoneme /b/.
Therefore, when a professional applies a naturalistic approach, APD testing can begin at any age the professional has the equipment, facilities, and materials to use to test a child under the necessary conditions needed to test at the specific age level. For example, infant speech perception testing requires very sophisticated equipment for determining a change in behavior where as testing a toddler would need less sophisticated equipment, and the equipment and materials for testing would become less involved as the child matures. Additionally, a professional taking this approach may use a variety of test materials and techniques that are not traditionally part of the APD test battery.
Why take a naturalistic approach? The professional may say that he or she is not looking for a diagnosis of APD. Instead, the purpose is to assess how a child handles auditory material and responds to it. Knowing the expected range of normal responses at the child’s age level can indicate to the professional whether the child is responding within age level expectations or below expected levels. Then, intervention may be recommended to help stimulate, develop or bring the child closer to age level normal responding or recommendations may be made to look for other indicators of developmental problems; that is, the child’s poor responses to auditory stimuli may suggest that auditory processing deficits are symptoms of a more general or global developmental disability.
This paper did not answer the question of the youngest age to test a child for APD. Instead it looked at three different approaches to assessing auditory processing and how this question of youngest age may be answered from each perspective. Thus, it is important for parents to ask professionals and for professionals to ask themselves “what is the approach to APD being taken, and how is age related to this approach?”
Bellis, T.J. (1996). Central Auditory Processing Disorders in the Edcuational Setting: From Science to Practice. San Diego, CA: Singular Publishing Group, Inc.
Chermak, G.D., and Musiek, F.E. (1997). Central Auditory Processing Disorders: New Perspectives. San Diego, CA: Singular Publishing Group, Inc.
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