Auditory Processing Disorders

An auditory processing disorder (APD) refers to difficulties with the processing of sound despite the ear being able to detect sounds at normal levels. Specifically, difficulties experienced with attending to, discriminating, recognising or understanding audible signals that cannot be attributed to either impaired hearing sensitivity or intellectual impairment.

The Charactersistics of APD

Those with APD will exhibit some, all or even none of the symptoms listed here:
•    Difficulty understanding speech in the presence of background noise or competing speech.
•    Seems to hear, but not understand what people say.
•    Distractibility and hyperactivity.
•    Inattentiveness and poor attention span.
•    Difficulty understanding verbal directions, or getting them confused.
•    Academic under-achievement and reading difficulties because of auditory-phonetic confusions.
•    Difficulty determining the direction a sound is coming from.

There are other disorders with similar characteristics, therefore, if your child has some, or even all, of these characteristics it does not automatically mean he or she has an APD.

Auditory Processing refers to the way our ears communicate with our brain and what our brain does with what it ‘hears’. However, CAP is more complex than this and actually reflects a specific set of auditory system mechanisms and skills that are needed to interpret what your ear hears. These include the ability to:

• determine the location of a sound
•  recognise auditory pattern
• understand in the presence of competing acoustic signals
• understand degraded acoustic signals
• discriminate the difference between sounds
• recognise temporal aspects of audition

Normal Auditory Processing also involves additional non-specific skills including;

• Attention: Attention-based skills relate to the attention given to speech and sounds in the environment. This is of particular importance when listening to instructions or screening out background noises.
  
• Auditory decoding: Auditory-decoding skills relate to the brains ability to recognise sounds and detect the differences between speech sounds.
  
• Associative: Association-based skills relate to the ability to associate incoming sounds with other information according to rules of language.
  
• Integration: Integration skills refer to the skills required to link multi-sensory information (e.g. reading/vision) and the rules of language to make sense of the information.
  
• Output-Organisation: Output-organisation skills relate to the skills involved in sequencing planning and organising responses, and recall of auditory information.

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Causes of APD:

There are a number of possible causes of APD, although the actual causes of APD are unknown. Some possible causes of APD include:

• Neurological deficits with the auditory system.
• Genetic traits.
• Early and frequent middle ear problems’ (such as otitis media or ‘glue ear’).

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Identification of an APD

A complete APD evaluation should include an extensive history, a standard hearing test to exclude peripheral loss, and it should aim to cover the important areas of CAP. So that the tests can be interpreted accurately, it is important the child being tested is able to understand language and communicate with others, have normal to near-normal intelligence and be at least 7 years old.

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Management of an APD

Management of children with APD usually involves a team of professionals (e.g. speech-language pathologists, psychologists, learning disabilities specialists, audiologists, neurologists, and physicians), Management focuses largely on the use of various strategies to maximise existing listening skills, encourage the development of new skills, and can be divided into three main categories;

Environmental Modifications
Adapting the listening environment to minimise noise levels and make speech louder than the background noise can improve the child’s ability to process auditory information. Modifications can include strategies such as preferential seating, classroom amplification etc.

Direct Intervention
Involves utilising techniques to improve auditory discrimination, auditory integration skills and auditory association skills. Examples of direct intervention include training your child to hear differences in sounds or words, teaching the child to pick out sounds or words when there is background noise, or teaching your child to use rhythm and temporal cues in speech.

Compensatory Strategies
Involves utilising techniques to compensate for the auditory deficit, and for coping in daily life.
Possible compensatory strategies may include;

• Developing listening skills by teaching the child to listen for meaning rather than exact repetition, wait until instructions are complete before beginning a task, use chunking of information, rehearsal and paraphrasing.
• Check for comprehension of instructions by gaining the child’s attention, rephrasing or restating important information, asking the child to repeat instructions and giving the child adequate response time.
• The use of external aids such as notebooks, calendars, mnemonics, tape decks.
• The use of a ‘buddy system’ to allow your child to check they have understood.

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