CAPD assessment and diagnosis

How do we test for and diagnose Central Auditory Processing Disorder?

It is broadly recognised that the identification and management of CAPD is a multi­disciplinary approach. Audiologists provide pivotal information for initial or differential diagnosis and assessment for auditory processing disorders. This may involve other health professionals such as speech pathologists, psychologists, and paediatricians if we are providing rehabilitation for children.

A comprehensive test battery is designed to minimise language and cognitive components so a more reliable picture of auditory processing skills can be obtained. Audiologists look at how auditory information is used. This sometimes involves listening to speech in noise, listening for different beeps, or recalling sets of information. Occasionally this can involve electrophysiological testing; where we set up electrodes and look at the brains neural response to stimulus.

Testing typically takes up to 1.5 hours to complete and can be quiet demanding on children. Once results are obtained, a multi-disciplinary approach is taken to provide guidance for effective remediation strategies and rule out any other factors such as language impairment issues, cognitive problems, or attention difficulties.

What tests are in our CAP battery?

Our test battery includes a range of assessments identifying how well the auditory system performs certain tasks. For example, one test is targeted towards how well someone can focus on a speaker when there are other noises distracting them from different spatial planes. Another investigates how well they can remember and manipulate verbal information. Other tests included look at binaural integration (how well we use information coming from different ears at the same time).

The results from these tests can lead to targeted potential remediation/treatment in the form of training, learning software or other devices for the classroom setting.

Central Auditory Processing Assessment (CAPD)

Our standard CAP test battery includes the following tests:

  • Pure Tone Audiometry (PTA) – is the key hearing test used to identify hearing threshold levels of an individual, enabling determination of the degree, type and configuration of a hearing loss.
  • Tympanometry and acoustic reflex threshold (TYMP/REFLEXES) – these tests supplement the pure tone audiometry tests and deal with the middle ear, but each test for different problems.
  • Listening in Spatialised Noise (LiSN) – tests the ability of a person with normal hearing to understand speech when there is noise coming from different directions.
  • Test of Auditory Processing Skills 3 (TAPS3) – is used to assess auditory memory – the skills we use to listen, process, store, and recall.
  • Quick Speech in Noise (QuickSIN) – is an adaptive, virtual-reality, test that measures how well people can understand speech in noisy environments and their ability to use the spatial cues that normally help differentiate a target talker from distracting speech sounds e.g. like listening to a teacher in a noisy classroom. An inability to use this information has been found to be a leading cause of difficulty understanding speech in noisy environments, such as the classroom.
  • Dichotic Digit (DD) – is a central auditory test that assesses binaural integration skills. This is the ability of the listener to process different information being presented to each ear at the same time.

In some cases we may elect to do additional tests should they be required. Your ENT or GP may also have requested additional tests to further exclude nerve issues from central auditory processing issues.

We would only do these tests if requested or if there was concerns with Auditory Dyssynchrony for instance. If there was abnormal pattern of results in the standard CAP test battery this could be suggested (eg poor speech reception scores in the presence of near normal hearing)

These assessments are:

  • Auditory Brainstem response (ABR) – this test uses a special computer to measure the way the child’s hearing nerve responds to different sounds. The ongoing electrical activity in the brain and recorded via electrodes placed on the scalp
  • Otoacoustic Emissions (OAE) – this test can detect blockage in the outer ear canal, as well as the presence of middle ear fluid and damage to the outer hair cells in the cochlea.

Why do patients need to be at least 7 years or older?

While they may be a particularly adept child to the parent or the individual enquiring, all the normative data (the information that we compare the child’s results against saying if this is normal or not) is based on age. There is no normative data for those under the age of 7 because of the unreliability in testing.

Testing can also be quite draining for children and requires a significant amount of attention. Most children under this age are unable to maintain focus and/or completely comprehend the tests accurately. This means tests would not provide reliable results.

Read more about Central Auditory Processing Disorder: