Children and adults experiencing auditory processing disorder (APD) may appear not to hear well; however, the underlying issue is “what the brain does with what the ears hear.”-Jack Katz. Their difficulty understanding speech increases significantly in noisy environments. For students of all ages, an active classroom can present extraordinary challenges. For adults, noisy restaurants or large groups can cause extreme difficulty.
What Is APD?
While hearing loss may be suspected initially, appropriate diagnostic audiologic evaluation will confirm if hearing levels are within normal limits. Most cases of APD present with normal hearing levels, though it is not uncommon to have APD with hearing loss that makes it difficult to understand speech. An estimated 3-5% of school-age children suffer from APD, a condition that affects their ability to process information correctly due to a disconnect between what they are hearing and how their brain responds to the sound. In adults, approximately 15% of military veterans exhibit symptoms of APD and individuals with stroke, traumatic brain injury, epilepsy, and neurologic tumors are susceptible to APD. Older adults with normal hearing may exhibit signs of age-related auditory processing deficits.
Again, most individuals with APD don’t actually have hearing loss. Studies have shown the majority are able to hear normally in quiet environments; the problem is in the way they process auditory information. Symptoms of APD may range from mild to severe and include difficulty with any of the following:
- Hearing in noisy environments
- Following conversations
- Remembering and/or comprehending spoken information
- Maintaining focus and attention
- Following multi-step directions multi-step
- Reading and spelling
- Processing nonverbal information
- Understanding verbal instructions
- Maintaining focus if other sounds are present
Individuals with APD may become withdrawn, isolated and depressed. Children often become disruptive and may take unnecessary risks or lash out at others. Because many of the behavioral issues closely mimic those associated with Attention Deficit Hyperactivity Disorder (ADHD) and other learning disabilities, an incorrect diagnosis is often made.
How Is APD Diagnosed?
An audiologist specializing in APD will administer a comprehensive assessment, first addressing hearing sensitivity, then testing ability to process auditory stimuli. Patients will complete testing in a soundproof booth. These tests consist of repeating words presented in different formats and also listening to tones presented in a variety of ways.
There are four basic APD categories identified in the Buffalo Model (Katz & Smith 1991 & 1992). It should be noted that Bellis and Ferre (2002) have also developed a similar category system that is similar. Usually, those with APD demonstrate problems in two or more of the categories. By breaking down the disorder into categories, it helps us better break down the complex problem into areas that are easier to understand and help us provide the appropriate treatment plan.
- The Decoding Category
- This category refers to quickly and correctly understanding and interpreting speech at the phonemic level. There is poor speech-sound discrimination and problems with phonics. They say “huh” and “what” quite often. There may also be articulation problems due to the mixed up auditory system. This occurs in the auditory cortex of the brain. The middle-posterior portion of the superior temporal lobe is responsible for phonemic discrimination, phonemic memory and phonemic synthesis-analysis.
- Tolerance-Fading Memory (TFM) Category
- This is a very complex and variable disorder and is associated with the corpus callosum. The individual has severe reading and spelling problems and are sometimes labeled dyslexic. These are more difficult to treat. They have difficulty relating to both visual and auditory information. This is because language in the left hemisphere and vision in the right hemisphere and with input on both sides it must cross over the corpus collosum. In young children there may sometimes be extreme delays.
- Integration Category
- This is a very complex and variable disorder and is associated with the corpus callosum. The individual has severe reading and spelling problems and are sometimes labeled dyslexic. These are more difficult to treat. They have difficulty relating to both visual and auditory information. This is because language in the left hemisphere and vision in the right hemisphere and with input on both sides it must cross over the corpus collosum. In young children there may sometimes be extreme delays.
- Organization Category
- The skills affected in this category are sequencing and organization. These individuals are generally disorganized and have difficulty following directions in order. Regions of the brain associated with these problems are in the fronto-temporal and fronto-temporal parietal regions of the brain.
Once a diagnosis of APD is made, the nature of the disorder is determined. There are many types of auditory processing deficits and, because each case is individual, APD may manifest itself in a variety of ways. Therefore, it is necessary to determine the type of auditory deficit a given patient exhibits so that individualized management and treatment activities may be recommended that address his or her specific areas of difficulty.
How is APD Treated?
Treatment of APD is highly individualized and focuses on three primary areas: changing the learning or communication environment, recruiting higher-order skills to help compensate for the disorder, and remediation of the auditory deficit itself.
There are a wide variety of treatment activities to address specific auditory deficits. Some may be computer-based, and others include one-on-one training with a therapist. Sometimes, home-based programs are appropriate, whereas others may require children to attend therapy sessions in school or at a local clinic. The type, frequency and intensity of therapy, like all aspects of APD intervention, should be highly individualized and programmed for the specific type of auditory disorder that is present.
Therapy Interventions for the Decoding Category
- Phonemic Training Program – The goal is to improve the brain’s concept of speech sounds. Complete a phonemic error analysis – what sounds are missed? Start with the most difficult sound and work down. Create a level that is “easy” to create success and then increase the level of difficulty gradually. Repetition in various contexts over time enables the brain to process speech quickly and accurately. Encourage speed if slow.
- Phonemic Synthesis – A sound by sound presentation to produce a word or a nonsense word. The child/adult has to say the synthesized word. This helps associate sounds with words and clarity of articulation.
Therapy Interventions for Tolerance Fading Memory Category
- Speech-in-Noise Desensitization Training – To desensitize understanding speech in noise, we gradually add noise to train listening. This can be analogous to an allergist who increases one’s tolerance for allergens by gradually increasing doses of the allergens. It is the same principle. When one has more difficulty with noise in one ear compared to the other, it makes sense to give that ear more training.
- Short Term Auditory Memory Training – Auditory memory problems are almost always associated with APD. In each of these therapies we start at a level that is easy and gradually increase the complexity. Digit recall is generally a good step to start at because it is easy to find the baseline and measure a patient’s progress.
- Auditory Sequencing Training – This is similar to short term auditory memory. However, it requires order of sequence.
Therapy Interventions for Integration Category
These are children who are hopefully receiving occupational therapy and other specialized training and instruction.
- Any treatment activities designed to improve the communication between the two brain hemispheres such as learning to play a musical instrument (piano and guitar), singing, dancing, soccer, swimming or learning to play chess. The toy “Simon” or “bop it” activities that teach part — other activities such as building models and working puzzles are also helpful. These treatment activities include the brain training by use of whole body movements during brain training tasks.
- Dichotic Listening Training – Using two iPods playing two books that play at different times into each ear. Adjust the volume, which is the signal to sound ratio to make it more challenging to attend to the book playing in the weaker ear so that ear has to work harder and thus build neuropathways.
Therapy Interventions for Organization Category
1. These are the areas of therapy involving executive function skills and complex language skills. This may include planning, organizing and formulating complex sentences to explain complex events, as well as providing brain training through cognitive rehabilitation techniques and protocols.
References
Dr. Jack Katz, August 4, 2011 Keynote Speaker at Audiology Conference, Wilmington, NC Dr. Teri Bellis, Ph.D. (2002) When the Brain Can’t Hear
Dr. Jack Katz, 2014 Audiology Online: APD Evaluation to Therapy: The Buffalo Model