A Deep Dive into APD

Having an auditory processing disorder diagnosis for your child does not always mean it’s a straight path ahead. Pay attention to the category and sub-type of APD because treatment will vary.

If you found this page on APD subtypes helpful, this article should be of interest also.  It goes through the models and thinking that goes into an auditory processing disorder diagnosis, and reviews the discussion on APD subtypes.

No two cases of APD are the same.  An APD diagnosis about your child, doesn’t mean it’s a straight path ahead to treatment. Pay attention to the category and sub-type of APD because treatment will vary.

If you’re feeling confused by the written APD diagnosis for your child, you may not be alone. As Professor Geraldine Wallach[1], from the speech-language pathology department at California State University, writes, it can be murky: “Speech-language pathologists (SLPs) may characterize APD using various descriptive phrases that mirror the definition (e.g., the student has a problem with auditory discrimination), or they may use other terms including auditory sequencing, auditory figure-ground, auditory blending, and auditory synthesis to capture the auditory processing weaknesses demonstrated by their students as they look toward intervention to strengthen or develop these skills.”

The Complexity of APD

APD is a dynamic and hotly debated area among experts and researchers. Even the definition – and whether it exists as a ‘distinct clinical disorder’ is contested. Even the American Speech Hearing Association (ASHA)  says those diagnosing APD need extensive knowledge and additional training beyond the standard professional studies.

At the core is the need for comprehensive language assessments to work out the weakness and language underpinnings to target needed interventions. In other words, you’ll want to have literacy goals set (and achieved) for your child.

That’s a lot to take in.

So, back to the sub-types of APD. Even before we start talking about them, there are two ‘types’:

  • Development (to do with age or immaturity)
  • Compensatory (such as after a brain lesion from an injury, such as a stroke).

APD diagnoses through the lens of three models

Then, APD is broken down into four or five categories, depending on which theoretical model your audiologist uses. The Buffalo Model describes four and the Bellis/Ferre Model describes five categories. What underpins the differences? The Buffalo Model uses a single central auditory test (Staggered Spondaic Word) with multi-dimensional scoring and drawing on 40 factors.

The Buffalo Model

The categories of the Buffalo Model (introduced in 1991) are:

  • Decoding – how fast and accurate speech is heard, listened to and processed. Such children have trouble accurately and quickly processes speech at the phonemic level.
  • Tolerance Fading Memory – this points to the child’s below-par short-term memory and their ability to hear speech and process language in noisy environments.
    • There are two sub-categories:
      • Auditory Noise Tolerance, and
      • Short Term Auditory Memory
  • Organization – this one points to deficits in executive function and social communication. This arises when they can’t find the right words to respond in a conversation. The issue is organizing thoughts and sequencing information.
  • Integration – covering poor readers, particularly those who struggle with spelling. They might find it tricky to take on visual and auditory information at the same time.

Meanwhile, while there are multiple auditory tests results the Bellis/Ferre Model (created 1992) uses to classify. This model is considered the main model audiologists use to diagnose and described as ‘Functional Deficit Profiling’. Because it’s so prominent, you might be interested to listen to the keynote speech of one of the Model’s creators, Dr Jeanane Ferre at a 2018 conference. In it, she says the brain is a remarkable piece of plastic, so for those with APD, you can “drill them and they will get better”.

The Bellis/Ferre Model

Here are the five types of the Bellis/Ferre Model and what they mean:

  • Decoding Deficit – primary auditory cortex – relates to spelling, appears to mimic hearing loss, difficulty hearing when in noisy environments, sound blending
  • Prosodic Deficit – non-primary (right) auditory cortex – these cover the ability to judge the intent of what’s being communicated, social-emotional concerns, perception, speaks in a monotone voice, has visuospatial problems and prosody (that’s the patterns of stress and intonation in a language)
  • Integration Deficit – corpus callosum – has issues linking prosody and language content and between their brain hemispheres, has phonological, auditory language and memory deficits, their coordination between their hands is poor
  • Auditory Associative deficit – left (associative) cortex – this related to poor math application and reading comprehension, problems understanding information that is increasingly complex on a linguistic level, and receptive language deficits
  • Output Organization deficit – temporal to frontal and/or efferent system – doesn’t hear well when there’s a lot of noise about, difficulties in motor planning, poor skills in organization, expressive language and word retrieval plus poor sequencing and follow through.

The Spoken Language Processing Model

And there’s also a latecomer third sub-type – Spoken Language Processing (SL-P) Model (Medwetsky, 2002). The S-LP Model is like the Buffalo Model but adds the elements of prosodic and fading memory.

You won’t know which one your child’s audiologist will use unless you ask. Kim Tillery, from the Fredonia State University of New York, says there are more similarities than differences between them.

Keeping learning about the APD

To do an even deeper dive into APD, check out a few of our other blogs:

Children and adults with APD can make a lot of headway with their disorder using tailored neuroscience-backed therapies.

If you like the sound of using a neuroscience-based approach to helping your child deal with APD and move forward in their education, reach out to Gemm Learning to see if we can help. We’ll be back in touch by phone, then we’ll do an online assessment with your child, from that we’ll create an individualized protocol. That’s a training program they can do 30 minutes a day at home with live support and coaching. Most interventions last six months and your child can make a reading gain of two or more years in that time