C/APD Update: New Developments on an Old Controversy

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In the past two years, I wrote a series of research-based posts (HERE and HERE) regarding the validity of (Central) Auditory Processing Disorder (C/APD) as a standalone diagnosis as well as questioned the utility of it for classification purposes in the school setting.

Once again I want to reiterate that I was in no way disputing the legitimate symptoms (e.g., difficulty processing language, difficulty organizing narratives, difficulty decoding text, etc.), which the students diagnosed with “CAPD” were presenting with.

Rather, I was citing research to indicate that these symptoms were indicative of broader linguistic-based deficits, which required targeted linguistic/literacy-based interventions rather than recommendations for specific prescriptive programs (e.g., CAPDOTS, Fast ForWord, etc.),  or mere accommodations.

I was also significantly concerned that overfocus on the diagnosis of (C)APD tended to obscure REAL, language-based deficits in children and forced SLPs to address erroneous therapeutic targets based on AuD recommendations or restricted them to a receipt of mere accommodations rather than rightful therapeutic remediation.

Today I wanted to update you regarding new developments, which took place since my last blog post was written 1.5 years ago, regarding the validity of “C/APD” diagnosis.

In April 2016, de Wit and colleagues published a systematic review in the Journal of Speech, Language, and Hearing Research. Their purpose was to review research studies describing the characteristics of APD in children and determine whether these characteristics merited a label of a distinct clinical disorder vs. being representative of other disorders.  After they searched 6 databases they chose 48 studies which satisfied appropriate inclusion criteria. Unfortunately, only 1 study had strong methodological quality and what’s even more disappointing, the children in their studies were very dissimilar and presented with incredibly diverse symptomology. The authors concluded that: “the listening difficulties of children with APD may be a consequence of cognitive, language, and attention issues rather than bottom-up auditory processing.”

In other words, because APD is not a distinct clinical disorder, a diagnosis of APD would not contribute anything to the child’s functioning beyond showing that the child is experiencing linguistically based deficits, which bear further investigation.

To continue, you may remember that in my first CAPD post I extensively cited a tutorial written by Dr. David DeBonis, who is an AuD. In his article, he pointed out numerous inconsistencies involved in CAPD testing and concluded that “routine use of CAPD test protocols cannot be supported” and that [CAPD] “intervention needs to be contextualized and functional.”

In July 2016, Iliadou, Sirimanna, & Bamiou published an article: “CAPD Is Classified in ICD-10 as H93.25 and Hearing Evaluation—Not Screening—Should Be Implemented in Children With Verified Communication and/or Listening Deficits” protesting DeBonis’s claim that CAPD is not a unique clinical entity and as such should not be included in any disease classification system.  They stated that DeBonis omitted the fact that “CAPD is included in the U.S. version of the International Statistical Classification of Diseases and Related Health Problems–10th Revision (ICD-10) under the code H93.25” (p. 368). They also listed what they believed to be a number of article omissions, which they claimed biased DeBonis’s tutorial’s conclusions.

The authors claimed that DeBonis provided a limited definition of CAPD based only on ASHA’s Technical report vs. other sources such as American Academy of Audiology (2010), British Society of Audiology Position Statement (2011), and Canadian Guidelines on Auditory Processing Disorder in Children and Adults: Assessment Intervention (2012).  (p. 368)

The also authors claimed that DeBonis did not adequately define the term “traditional testing” and failed to provide several key references for select claims.  They disagreed with DeBonis’s linkage of certain digit tests, as well as his “lumping” of studies which included children with suspected and diagnosed APD into the same category. (p. 368-9)  They also objected to the fact that he “oversimplified” results of positive gains of select computer-based interventions for APD, and that in his summary section he listed only selected studies pertinent to the topic of intelligence and auditory processing skills. (p. 369).

Their main objection, however, had to do with the section of DeBonis’s article that contained “recommended assessment and intervention process for children with listening and communication difficulties in the classroom”.  They expressed concerns with his recommendations on the grounds that he failed to provide published research to support that this was the optimal way to provide intervention. The authors concluded their article by stating that due to the above-mentioned omissions they felt that DeBonis’s tutorial “show(ed) unacceptable bias” (p. 370).

In response to the Iliadou, Sirimanna, & Bamiou, 2016 concerns, DeBonis issued his own response article shortly thereafter (DeBonis, 2016). Firstly, he pointed out that when his tutorial was released in June 2015 the ICD-10 was not yet in effect (it was enacted Oct 1, 2015). As such his statement was factually accurate.

Secondly, he also made a very important point regarding the C/APD construct validity, namely that it fails to satisfy the Sydenham–Guttentag criteria as a distinct clinical entity (Vermiglio, 2014). Namely, despite attempts at diagnostic uniformity, CAPD remains ambiguously defined, with testing failing to “represent a homogenous patient group.” (p. 906).

For those who are unfamiliar with this terminology (as per direct quote from Dr. Vermiglio’s presentation): “The Sydenham-Guttentag Criteria for the Clinical Entity Proposed by Vermiglio (accepted 2014, JAAA) is as follows:

  1. The clinical entity must possess an unambiguous definition (Sydenham, 1676; FDA, 2000)
  2. It must represent a homogeneous patient group (Sydenham, 1676; Guttentag, 1949, 1950; FDA, 2000)
  3. It must represent a perceived limitation (Guttentag, 1949)
  4. It must facilitate diagnosis and intervention (Sydenham, 1676; Guttentag, 1949; FDA, 2000)

Thirdly, DeBonis addressed Iliadou, Sirimanna, & Bamiou, 2016 concerns that he did not use the most recent definition of APD by pointing out that he was most qualified to discuss the US system and its definitions of CAPD, as well as that “the U.S. guidelines, despite their limitations and age, continue to have a major impact on the approach to auditory processing disorders worldwide” (p.372). He also elucidated that: the AAA’s (2010) definition of CAPD is “not so much built on previous definitions but rather has continued to rely on them” and as such does not constitute a “more recent” source of CAPD definitions. (p.372)

DeBonis next addressed the claim that he did not adequately define the term “traditional testing”. He stated that he defined it on pg. 125 of his tutorial and that information on it was taken directly from the AAA (2010) document. He then explained how it is “aligned with bottom-up aspects of the auditory system” by citing numerous references (see p. 372 for further details).  After that, he addressed Iliadou, Sirimanna, & Bamiou, 2016 claim that he failed to provide references by pointing out the relevant citation in his article, which they failed to see.

Next, he proceeded to address their concerns “regarding the interaction between cognition and auditory processing” by reiterating that auditory processing testing is “not so pure” and is affected by constructs such as memory, executive function skills, etc. He also referenced the findings of  Beck, Clarke and Moore (2016)  that “most currently used tests of APD are tests of language and attention…lack sensitivity and specificity” (p. 27).

The next point addressed by DeBonis was the use of studies which included children with suspected vs. confirmed APD. He agreed that “one cannot make inferences about one population from another” but added that the data from the article in question “provided insight into the important role of attention and memory in children who are poor listeners” and that “such listeners represent the population [which] should be [AuD’s] focus.” (p.373)

From there on, DeBonis moved on to address Iliadou, Sirimanna, & Bamiou, 2016 claims that he “oversimplified” the results of one CBAT study dealing with effects of computer-based interventions for APD. He responded that the authors of that review themselves stated that: “the evidence for improving phonological awareness is “initial”.

Consequently, “improvements in auditory processing—without subsequent changes in the very critical tasks of reading and language—certainly do not represent an endorsement for the auditory training techniques that were studied.” (p.373)

Here, DeBonis also raised concerns regarding the overall concept of treatment effectiveness, stating that it should not be based on “improved performance on behavioral tests of auditory processing or electrophysiological measures” but ratheron improvements on complex listening and academic tasks“. (p.373) As such,

  1. “This limited definition of effectiveness leads to statements about the impact of certain interventions that can be misinterpreted at best and possibly misleading.”
  2. “Such a definition of effectiveness is unlikely to be satisfying to working clinicians or parents of children with communication difficulties who hope to see changes in day-to-day communication and academic abilities.” (p.373)

Then, DeBonis addressed Iliadou, Sirimanna, & Bamiou, 2016 concerns regarding the omission of an article supporting CAPD and intelligence as separate entities. He reiterated that the aim of his tutorial was to note that “performance on commonly used tests of auditory processing is highly influenced by a number of cognitive and linguistic factors” rather than to “do an overview of research in support of and in opposition to the construct”. (p.373)

Subsequently, DeBonis addressed the Iliadou, Sirimanna, & Bamiou, 2016 claim that he did not provide research to support his proposed testing protocol, as well as that he made a figure error. He conceded that the authors were correct with respect to the figure error (the information provided in the figure was not sufficient). However, he pointed out that the purpose of his tutorial was to “to review the literature related to ongoing concerns about the use of the CAPD construct in school-aged children and to propose an alternative assessment/intervention procedure that moves away from testing “auditory processing” and moves toward identifying and supporting students who have listening challenges”. As such, while the effectiveness of his model is being tested, it makes sense to “use of questionnaires and speech-in-noise tests with very strong psychometric characteristics” and thoroughly assess these children’s “language and cognitive skills to reduce the chance of misdiagnosis”  in order to provide functional interventions (p.373).

Finally, Debonis addressed the Iliadou, Sirimanna, & Bamiou, 2016 accusation that his tutorial contained “unacceptable bias”. He pointed out that “the reviewers of this [his 2015 article article] did not agree” and that since the time of that article’s publication “readers and other colleagues have viewed it as a vehicle for important thought about how best to help children who have listening difficulties.” (p. 374)

Having read the above information, many of you by now must be wondering: “Why is the research on APD as a valid stand alone diagnosis continues to be published at regular intervals?”

To explain the above phenomenon, I will use several excerpts from an excellent presentation by Kamhi, A, Vermiglio, A, & Wallach, G (2016), which I attended during the 2016 ASHA Convention in Philadephia, PA.

It has been suggested that the above has to do with: “The bias of the CAPD Convention Committee that reviews submissions.” Namely, “The committee only accepts submissions consistent with the traditional view of (C)APD espoused by Bellis, Chermak and others who wrote the ASHA (2005) position statement on CAPD.”

Kamhi Vermiglio, and Wallach (2016) supported this claim by pointing out that when Dr. Vermiglio attempted to submit his findings on the nature of “C/APD” for the 2015 ASHA Convention, “the committee did not accept Vermiglio’s submission” but instead accepted the following seminar: “APD – It Exists! Differential Diagnosis & Remediation” and allocated for it “a prominent location in the program planner.”

Indeed, during the 2016 ASHA convention alone, there was a host of 1 and 2-hour pro-APD sessions such as: “Yes, You CANS! Adding Therapy for Specific CAPDs to an IEP“, “Perspectives on the Assessment & Treatment of Individuals With Central Auditory Processing Disorder (CAPD)“, as well asThe Buffalo Model for CAPD: Looking Back & Forward, in addition to a host of posters and technical reports attempting to validate this diagnosis despite mounting evidence refuting that very fact. Yet only one session, “Never-Ending Controversies With CAPD: What Thinking SLPs & Audiologists Know” presented by Kamhi, Vermiglio, & Wallach (two SLPs and one AuD) and accepted by a non-AuD committee, discussed the current controversies raging in the fields of speech pathology and audiology pertaining to “C/APD”. 

In 2016, Diane Paul, the Director of Clinical Issues in Speech-Language Pathology at ASHA  had asked Kamhi, Vermiglio, and Wallach “to offer comments on the outline of audiology and SLP roles in assessing and treating CAPD”.  According to Kamhi, et al, 2016, the outline did not mention any of controversies in assessment and diagnosis documented by numerous authors dating as far as 2009. It also did not “mention the lack of evidence on the efficacy of auditory interventions documented in the systematic review by Fey et al. (2011) and DeBonis (2015).”

At this juncture, it’s important to start thinking regarding possible incentives a professional might have to continue performing APD testing and making prescriptive program recommendations despite all the existing evidence refuting the validity and utility of APD diagnosis for children presenting with listening difficulties.

Conclusions:

  • There is still no compelling evidence that APD is a stand-alone diagnosis with clear diagnostic criteria
  • There is still no compelling evidence that auditory deficits are a “significant risk factor for  language or academic performance”
  • There is still no compelling evidence that “auditory interventions provide any unique benefit to auditory, language, or academic outcomes” (Hazan, Messaoud-Galusi, Rosan, Nouwens, & Shakespeare, 2009; Watson & Kidd, 2009)
  • APD deficits are linguistically based deficits which accompany a host of developmental conditions ranging from developmental language disorders to learning disabilities, etc.
  • SLPs should continue comprehensively assessing children diagnosed with “C/APD” to determine the scope of their linguistic deficits
  • SLPs should continue formulating language goals to  determine linguistic areas of weaknesses
  • SLPS should be wary of any goals or recommendations which focus on remediation of isolated skills such as: “auditory discrimination, auditory sequencing, phonological memory, working memory, or rapid serial naming” since studies have definitively confirmed their lack of effectiveness (Fey, et al, 2011)
  • SLPs should be wary of any prescriptive programs offering C/APD “interventions”
  • SLPs should focus on improving children’s abilities for functional communication including listening, speaking, reading, and writing
    • Please see excellent article written by Dr. Wallach in 2014 entitled: Improving Clinical Practice: A School-Age and School-Based Perspective. It “presents a conceptual framework for intervention at school-age levels” and discusses “advanced levels of language that move beyond preschool and early elementary grade goals and objectives with a focus on comprehension and meta-abilities.”

So there you have it, sadly, despite research and logic, the controversy is very much alive! Except I am seeing some new developments!

I see SLPs, newly-minted and seasoned alike, steadily voicing their concerns regarding the symptomology they are documenting in children diagnosed with so-called “CAPD” as being purely auditory in nature.

I see more and more SLPs supporting research evidence and science by voicing their concerns regarding the numerous diagnostic markers of ‘CAPD’ which do not make sense to them by stating “Wait a second – that can’t be right!”.

I see more and more SLPs documenting the lack of progress children make after being prescribed isolated FM systems or computer programs which claim to treat “APD symptomology” (without provision of therapy services).  I see more and more SLPs beginning to understand the lack of usefulness of this diagnosis, who switch to using language-based interventions to teach children to listen, speak, read and write and to generalize these abilities to both social and academic settings.

I see more and more SLPs beginning to understand the lack of usefulness of this diagnosis, who switch to using language-based interventions to teach children to listen, speak, read and write and to generalize these abilities to both social and academic settings.

So I definitely do see hope on the horizon!

References:

(arranged in chronological order of citation in the blog post):

Related Posts:

 

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