Auditory Processing Disorder
A person's ability to process auditory information involves a continuum of skills. Here is a list of these skills and who should assess them:
Auditory processing (Audiologist)
Intact peripheral auditory system to perceive and receive acoustic stimulus and intact Central Auditory Nervous System (CANS) to transmit acoustic signal through the brain to the upper cortex
Phonemic processing (Speech-Language Therapist)
Phonemic knowledge to discriminate / recognise sounds and words
Language processing (Speech-Language Therapist)
Linguistic knowledge to discriminate / recognise the meaning of words / messages
Cognitive processing (Psychologist)
Executive function skills to pay attention to the acoustic stimulus and to organise and execute a behavioural response
Our recommendation
Listening, literacy, and learning difficulties are most readily explained by poor attention, poor auditory memory, poor phonological awareness, or poor language comprehension skills - or a combination of these. We therefore recommend screening to rule out difficulties in any of these areas before deciding whether or not it would appropriate to proceed with expensive APD assessment. Children with poor attention, poor auditory memory, poor phonological awareness or poor language comprehension skills need intervention that works directly on improving these skills.
The role of the Audiologist
APD or C(APD) is traditionally diagnosed by an Audiologist. The role of the Audiologist is to rule out hearing loss and to assess the auditory mechanisms that underlie the following abilities:
Cautionary advice
In its Technical Report on APD (2005), the American Speech-Language-Hearing Association (ASHA)'s states: "Although abilities such as phonological awareness, attention to and memory for auditory information, auditory synthesis, comprehension and interpretation of auditory presented information, and similar skills may be reliant on or associated with intact auditory function, they are considered higher order cognitive communicative and / or language related functions, and thus are not included in the definition of (C)APD".
This means that a (C)APD diagnosis should not be made on the basis of poor phonological awareness, poor memory, poor comprehension, etc. In fact, Audiologists must ensure that a child's performance on behavioural auditory processing tests is not affected by co-occurring difficulties in any of the other collateral areas identified as underpinning a person's listening skills: their phonemic, linguistic and cognitive processing skills. ASHA's Report goes on to advise that when there is suspicion of speech or language impairment, or intellectual, psychological, or other deficits, "referral to the appropriate professional(s) should precede (C)AP testing to ensure accurate interpretation of results." And in some cases, co-morbid diagnoses will necessarily preclude (C)AP testing.
- Sound localisation and lateralisation
- Auditory discrimination
- Auditory pattern recognition
- Temporal aspects of audition, including temporal integration, temporal discrimination (e.g.: temporal gap detection), temporal ordering, and temporal masking
- Auditory performance in competing acoustic signals (including dichotic listening)
- Auditory performance with degraded acoustic signals
Cautionary advice
In its Technical Report on APD (2005), the American Speech-Language-Hearing Association (ASHA)'s states: "Although abilities such as phonological awareness, attention to and memory for auditory information, auditory synthesis, comprehension and interpretation of auditory presented information, and similar skills may be reliant on or associated with intact auditory function, they are considered higher order cognitive communicative and / or language related functions, and thus are not included in the definition of (C)APD".
This means that a (C)APD diagnosis should not be made on the basis of poor phonological awareness, poor memory, poor comprehension, etc. In fact, Audiologists must ensure that a child's performance on behavioural auditory processing tests is not affected by co-occurring difficulties in any of the other collateral areas identified as underpinning a person's listening skills: their phonemic, linguistic and cognitive processing skills. ASHA's Report goes on to advise that when there is suspicion of speech or language impairment, or intellectual, psychological, or other deficits, "referral to the appropriate professional(s) should precede (C)AP testing to ensure accurate interpretation of results." And in some cases, co-morbid diagnoses will necessarily preclude (C)AP testing.
