Breakdown In The Hearing Process
Central Auditory Processing Disorder (CAPD) is an umbrella term for a variety of disorders that result in a breakdown in the hearing process. In short, our brain cannot make sense of what our ears hear because the auditory signal is distorted in some way. As a result, one of the biggest problems experienced by individuals with CAPD is difficulty listening in background noise.
Affects Two To Five Percent of Children
CAPD is said to affect about two to five percent of children, but the percentage is not precisely known. Children with the disorder display a number of behaviours similar to the symptoms associated with sensorineural hearing loss. For example, they may complain that they find it difficult to hear when the classroom is noisy. These behaviours may become apparent in the early school years, or at a later stage of the child’s life, due to changes in the acoustic environment, or to increased academic demands.
As a result of their difficulty hearing in noise, children with CAPD may suffer from “auditory fatigue“.
Have you ever been in a noisy restaurant, cutlery and crockery clanging and lots of people talking? After a while, the effort of trying to hear in this environment can make you tired. Could you imagine if this is what it was like for you every day? Sometimes it is just easier to stop trying to listen. This may happen to children with CAPD. They may “give up” and be labelled as lazy or withdrawn. They could also “act out” in an effort to divert attention from their inability to hear and process speech in the classroom.
Causes of CAPD
We don’t know exactly what causes the disorder, but the neural pathways of the central auditory nervous system are involved in some way. Children who have experienced repeated episodes of otitis media (glue ear) may be particularly susceptible to CAPD, perhaps due to the fact that their hearing levels fluctuate during periods of infection, affecting normal exposure to sound and compromising development of the auditory pathways. However, many children affected by the disorder have never had glue ear. Routine audiological tests will not diagnose CAPD and pure tone audiometry results in this population are typically normal. If CAPD is suspected, assessment will involve a variety of specialised audiological tests.
Although children with CAPD generally have normal overall intelligence, if left untreated it may lead to academic deficits in areas such as phonics, reading, and spelling. It may be the emergence of academic deficits that alerts a teacher, parent or other professional to suspect CAPD. However, it is vitally important to determine whether a child’s difficulty comprehending speech in the classroom is actually related to this or whether the child’s difficulty is caused by another disorder altogether (such as attention, memory or speech- language problems, or even anxiety and motivation).
Effects of CAPD
So what specific auditory abilities are affected if a child has CAPD? The American Speech- Language-Hearing Association defined CAPD as a deficit in one or more of a number of skills, including difficulties knowing where a sound is coming from (sound localisation); the ability to detect changes in the duration of, and time intervals between auditory stimuli (temporal processing); and the ability to detect spectral variations in auditory stimuli (particularly those that differentiate sounds according to formant transitions between phonemes).
The Central Auditory Processing Disorder treatment program to help a child with CAPD will depend on the type of deficit that is diagnosed. If a child has CAPD, a Personal Frequency Modulation (FM) device or sound-field amplification system can be used to improve the signal-to-noise ratio in the classroom. The child could also be trained in auditory closure skills and vocabulary building to improve their ability to use contextual cues to fill in missing sections of auditory information.
Whereas a lot of emphasis has been placed on children with normal hearing thresholds with CAPD in this overview, it is important to remember that Auditory Processing Problems in Adults are also common.
What to do if you suspect a child has CAPD?
Early identification is important for children with CAPD. So if you suspect your child may be having difficulties processing sounds, it’s important to speak about your concerns with our Audiologists, trained in the relevant treatment.
For further information download our CAPD Brochure.
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