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What is APD?

Central auditory processing disorders (CAPD), also referred to as APD, is when someone has difficulty processing or interpreting sounds by the brain, despite having normal hearing. In short, it can be simply defined as a problem with "what the brain does" with "what it hears".

People with auditory processing disorder difficulties often have normal hearing sensitivity but their brain struggles to interpret, organize, and remember what is said, especially in background noise. Children with auditory processing problems are weak in some basic skills for decoding and remembering what they hear. They often miss, or misunderstand, information that is conveyed orally, in instruction or conversation.

On this page, you can find information about a variety of topics related to auditory processing, commonly observed symptoms, screening and assessment, and benefits of therapy. Click on the links below to view information on different aspects of APD.

Information about APD

Click on the links below to navigate to a section on this page.

Auditory Processing Skills

The human brain possesses a variety of auditory processing skills that allow it to interpret sounds. These skills are most often dependent on each other. The brain uses these skills in different combinations to help a person hear what is happening around them and understand what it means.



Temporal Processing

Identifying timing and pitches


Taking sounds coming from two ears and putting it together

Tolerance-Fading Memory

Sorting through competing sounds/noise and remembering what is heard

Relation Between Auditory Skills and Effective Communication

As a speaker arranges thoughts in the brain and starts speaking to a listener there are 2 processes happening - the listener hears the spoken message which is conveyed to their brain. The speaker then hears their own articulation of speech though a feedback link, where the speaker’s ear picks up their own voice and send it to the brain to process it. As the role of the speaker is finished, the listener would then take up the role of the speaker and the whole process is repeated.

How Does APD Affect Learning

Children receive a lot of instruction both at home and at school – whether it is for obeying their parents, learning a new task, reading, math or other educational activity, interacting with or playing other kids, and many others. If the child is suffering from auditory processing disorder, you begin to see many occasions when the child fails to understand simple or mildly complex instructions.

Even in situations when the child is provided with visual aids like pictures, text, or video, they can still have trouble understanding the audio content. This can make it difficult for them to understand what they are hearing especially in noise, have difficulty communicating with their friends or classmates and awkwardness in social situations (for example, classrooms or family gatherings).

Children with APD have difficulty performing tasks when they are instructed orally. They appear disconnected and confused and may respond inappropriately in several situations. In fact, it is quite possible that a child with APD may fare worse than a child with hearing impairment because inability to process a full range of audio is more problematic than hearing nothing at all.

Common Signs and Behaviour

A person or child with APD may exhibit difficulty with auditory processing in the following ways.

Screening for APD and Getting Assessed

If you or your child exhibit any of the signs and symptoms, it would be helpful to screen for APD in order to rule out the need for a comprehensive diagnostic assessment. Screening would help in identifying those for whom a comprehensive auditory processing evaluation is warranted, while, at the same time reduces the number of inappropriate referrals.

We highly recommended that you or your child take a screening test for APD if you exhibit difficulty with auditory processing because it:

The Need for APD Testing

How is APD Identified and Diagnosed

APD diagnosis, testing and therapy have seen significant advances in the last 60 years with the development of research-based testing protocols. However, prior to testing for APD, it is mandatory to rule out hearing loss as any degree of hearing loss, however small it may be, raises auditory processing concerns.

APD testing is typically conducted on children or adult who have normal hearing, or already wear hearing assistive devices (e.g. hearing aids) to compensate for hearing loss. APD testing can be conducted on children as young as 3 and a half years old. It is advisable for children suspected of having APD to get tested as early as possible, as it can greatly improve their academic and social success.

There are different testing protocols currently in use for APD testing – Buffalo model, Terri Bellis model, to name a few. The purpose of these tests is to assess APD using a series of tests that target decoding, integration, tolerance fading memory and organization difficulties. Apart from testing for APD, the Buffalo model testing procedure also includes separate modules for therapy which improve a person’s auditory processing skills.

During an APD test, the client or child is presented with a series of tests to determine how their brain identifies and uses sounds and words in both quiet and noise. The stimulus (sounds) used in these tests target specific centers in the brain for language, speech, memory, and comprehension. In addition to regular APD testing, both children and adults can also be assessed using an interactive test called Acoustic Pioneer, which is available as an iOS application on Apple-related devices such as an iPhone or iPad. The application was designed and validated by an audiologist named Matthew Barker, and is a great tool to use for diagnostics and also for measuring progress with therapy.

How does APD Testing Help?

APD assessment using a formalized testing procedure is highly beneficial in the following aspects.

Intervention for APD

Although there are several strategies to APD intervention, none of them are aimed directly at therapy. The therapy program is targeted to improve decoding, integration, organization and tolerance fading memory deficits by training to blend sounds together, improving the degree to which they are remembered effectively, how such sounds are synthesized into words, improving hearing abilities in noise, improving sequencing abilities, dichotic listening training (hearing different sounds in both ears simultaneously) and some non-auditory approaches.

For younger children, we are able to provide access to two different therapy apps from the same developer of Acoustic Pioneer. These apps are a great way to practice dichotic listening and temporal processing, and report back weekly progress.

Benefits of APD Therapy - Procedural Aspects and Improvement Areas

The results and outcomes of therapy are long lasting and are achievable in a short period of time. APD therapy is most helpful in improving:

The weaknesses in auditory processing are treated from a multi-system coordination of skills perspective. This includes

The Buffalo Model for Auditory Processing Therapy

Therapy is based on Jack Katz’s Buffalo Model of Auditory Processing Therapy (Katz, 2007, 2009; Katz & Fletcher, 2004) which includes:

How Can We Help Children With APD?

To help children who have APD, it is important to understand the problems associated with APD and how they affect daily activity, response to situations and performance of the child. The following strategies can be used either at home or at school to ease some of the difficulties associated with APD. These strategies can prove greatly beneficial when used together with APD therapy.

Schedule an appointment for CAPD services

If you would like to make an appointment for in-clinic or online APD assessment and/or therapy, please contact us directly through email or phone. You can also complete our APD screening questionnaire and provide us with your contact information, and we will reach out to you as soon as we review your responses.