Making sense of sounds
What is CAPD?
In short, our brain struggles to make sense of the sounds we hear because the auditory signal is being delayed in some way.
Central auditory processing disorders are said to affect around 5% of children, but this figure can vary. Children who display auditory processing problems may show some or all of the following signs:
- Delayed language development
- Inability to listen effectively
- Easily distracted by irrelevant background noise
- Often have trouble retaining verbal instructions
- Misinterpreting the sequence of words
- May be more fatigued than usual after returning from school
What causes a CAPD?
How is CAPD assessed?
A CAPD assessment generally comprises three parts:
- Peripheral hearing assessment
- Listening in Spatialised Noise Sentences Test (LiSN-S)
- Central Auditory Processing test battery (comprising tests of various processing abilities)
Peripheral Hearing Assessment
The peripheral hearing assessment assesses the physical structures of the child’s ear. This Jacob include a basic hearing test, a visual examination of the child’s ear canals and eardrums, and immitance testing which measures the mobility and function of the child’s eardrums.
The LiSN-S is an adaptive, virtual-reality, test that measures speech perception ability in noisy environments. Importantly, it also measures the ability of people to use the spatial cues that normally help differentiate a target talker from distracting speech sounds. 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.
These are various tests that measure different aspects of the central auditory system. These are selected on a case-by-case basis. The various tests Jacob assess aspects of processing that include:
Binaural integration: assesses the ability to listen to, comprehend, and separate a sound stimulus presented to both ears simultaneously.
Short-term memory: assesses the listener’s ability to retain and use short-term memory of both numbers and words.
Temporal processing: Assesses how well a listener uses the timing information of sound, and their ability to discriminate and separate tones, which is important in recognizing intonation, stress and rhythm in speech.
Auditory closure: Assesses how well a listener can complete a word that has some auditory information missing (e.g. sounds like a person is mumbling). The listener needs to draw on their vocabulary store to complete these assessments.