Auditory Processing Disorder or ADD?

 

It Is Difficult to Distinguish Symptoms of Auditory Processing Disorder from Symptoms of Attention Deficit Disorder

The psychologist Keller (1992) noted that the differential diagnosis between Auditory Processing Disorder (APD) and Attention Deficit Disorder (ADD) is often determined primarily by the identity of the first professional whom the family consults: an audiologist or a psychologist.

Moore (2018) proposed that developmental immaturity in hearing and listening among children aged six and older is largely caused by difficulty directing attention, understanding, and remembering challenging auditory tasks, rather than by an auditory processing disorder.

These statements reflect the difficulty of distinguishing auditory processing disorder from other disorders, particularly attention deficit disorder.

The American Speech-Language-Hearing Association (ASHA) and the American Academy of Audiology (AAA) define auditory processing as the efficiency with which the central nervous system uses auditory information. Auditory processing includes the mechanisms underlying sound localization, auditory discrimination, recognition of sound patterns, temporal aspects of sound processing, auditory processing in the presence of competing acoustic signals, and auditory processing when acoustic signals are degraded.

According to this definition, auditory processing disorder is a difficulty in processing auditory information within the central nervous system. It is expressed as poor performance in one or more of the abilities listed above and is not caused by higher-order cognitive, communicative, or linguistic functions.

Many audiologists associate auditory processing with listening difficulties. Wilson (2019) proposed a three-stage definition resembling the DSM-IV definition of a learning disability:

1. A discrepancy between ability and achievement: “unexplained listening difficulties.”
2. Poor performance on tests that assess listening and also require auditory processing, attention, memory, and/or language.
3. Exclusionary factors do not provide a better explanation for the listening difficulties. Such factors may include an attention disorder, autism spectrum disorder, a language impairment, or a memory disorder.

Moore recommends defining auditory processing disorder as an impairment in the way auditory stimuli are processed that is not caused by a hearing problem and is not the result of a primary impairment in memory, attention, or language.

Bench and colleagues (2020) proposed using the definitions of the Cattell-Horn-Carroll (CHC) model to define auditory processing disorder and distinguish it from attention deficit disorder as defined in the DSM-5. This proposal gives us an opportunity to review the definitions of auditory processing ability and attention deficit disorder.

Auditory Processing in the CHC Model

In the CHC model, auditory processing is defined as “the ability to detect, discriminate, remember, reason about, and work creatively with auditory stimuli, which may consist of tones, environmental sounds, and speech units” (Schneider & McGrew, 2018).

Auditory processing is what the brain does with auditory information, sometimes long after that information has reached the ear. Our ability to “hear” a song in the mind’s ear, that is, to create an auditory image, is an example of auditory processing that does not depend on an auditory stimulus that is currently present.

Auditory processing is not the same as understanding spoken language. Understanding spoken language requires additional aspects of semantics or meaning, grammar, and syntax, which are associated with crystallized knowledge. Auditory processing concerns the sounds of words alone, without their semantic content.

Auditory processing includes narrow abilities related to distinguishing between phonemes and tones of voice, detecting emphasis during speech, hearing spoken words accurately under distortion or background noise, holding sounds, sound patterns, voices, or speech sounds in mind for a short period, identifying and maintaining a musical rhythm, distinguishing between musical sound patterns, identifying pitch and localizing sounds in space.

Auditory processing plays an important role in activities such as conversation, navigating in the dark, playing music, acquiring a foreign language, and reading. It includes complex cognitive processes such as attention, spatial localization of sounds, memory, breaking words down into sounds, and identifying sound patterns.

In the American versions of the Woodcock-Johnson III and IV Tests, auditory processing ability is more strongly correlated with general intellectual ability than visual processing ability is, across all age groups.

Schneider and McGrew (2018) note that the ability to keep track mentally of sounds, voices, or sound patterns and manipulate them, for example by counting or rearranging them, depends on attentional control, which is part of working memory.

Attention Deficit Disorder According to the DSM-5

A diagnosis of ADD requires, according to the DSM-5, a persistent pattern of inattention that interferes with functioning or development.

At least six of the following symptoms are also required. They must have been present for at least six months to a degree that is inconsistent with the person’s developmental level and that negatively affects academic or occupational activities. Some of the symptoms must have appeared before the age of 12 and must be present in at least two settings:

a. Often fails to pay close attention to details or makes careless mistakes.

b. Often has difficulty sustaining attention in tasks or activities.

c. Often appears not to listen when spoken to directly.

d. Often has difficulty organizing tasks and activities.

e. Often avoids, dislikes, or is reluctant to engage in tasks that require sustained mental effort.

f. Often loses things needed for tasks or activities.

g. Is often easily distracted by external stimuli.

h. Is often forgetful in daily activities.

The Study by Bench and Colleagues

Bench and colleagues (2020) examined whether children referred to a clinic because of suspected auditory processing disorder also met the criteria for ADD.

The study included the mothers of 149 children aged 6 to 16, 61% of whom were boys. The children had not been diagnosed with autism spectrum disorder, oppositional defiant disorder, severe anxiety, clinical depression, or intellectual developmental disability.

The mothers completed the Behavior Rating Inventory of Executive Function (BRIEF), which assesses executive functions, and an ADHD questionnaire. According to these questionnaires, 66% of the children were rated as functioning below average, by at least one standard deviation, on the attention measure. In addition, 80% of the children were rated as functioning below average, by at least one standard deviation, on the executive-function measure. This included an inability to initiate, plan, and organize, and to hold a problem in working memory until it could be solved.

The researchers showed the mothers a card listing on one side symptoms of auditory processing disorder based on the CHC narrow abilities in this domain, and on the other side symptoms of attention deficit disorder based on the DSM-5. The symptom lists did not include the names of the disorders they described. The mothers were asked to indicate the extent to which their child displayed symptoms from each group. Symptoms of ADD described approximately 90% of the children “fairly well” or “very well.” Symptoms of auditory processing disorder described only approximately 23% of the children “fairly well” or “very well.” These results were consistent with the findings from the BRIEF and ADD questionnaires.

However, I think it is difficult to evaluate the presence of auditory processing symptoms merely by observing a child in everyday life. The researchers did not report how many of the children in the study were ultimately diagnosed with auditory processing disorder. In addition, they relied exclusively on questionnaires and did not administer tests assessing either auditory processing or attention deficit disorder.

Nevertheless, the findings discussed above may emphasize the need to assess attention in children who have auditory processing difficulties, as well as the need to assess auditory processing in children who have attention deficit disorder.

References

Bench, J., Jacobs, K., & Furlonger, B. (2020). On differentiating auditory processing disorder (APD) from attention deficit disorder (ADD): An illustrative example using the Cattell-Horn-Carroll (CHC) model of cognitive abilities. International Journal of Audiology, 59(3), 224–229.

Keller, W. D. (1992). Auditory processing disorder or attention deficit disorder? In J. Katz, N. A. Stecker, & D. Henderson (Eds.), Central auditory processing: A transdisciplinary view (p. 112). St. Louis, MO: Mosby.

Moore, D. R. (2018). Challenges in diagnosing auditory processing disorder. The Hearing Journal, 71(10), 36.

Schneider, W. J., & McGrew, K. S. (2018). The Cattell-Horn-Carroll theory of cognitive abilities. In D. P. Flanagan & E. M. McDonough (Eds.), Contemporary intellectual assessment: Theories, tests, and issues. New York, NY: Guilford Press.

Wilson, W. J. (2019). On the definition of APD and the need for a conceptual model of terminology. International Journal of Audiology, 58(8), 516–523. https://doi.org/10.1080/14992027.2019.1600057