Auditory Processing Disorder Type Descriptions
Auditory Processing Disorder will not present the same way in every child, though it is rare to find a child who only suffers in one of the listed areas. APD usually exists as a blend of difficulties – however, one issue may be more dominant than the others. The main types of APD identified in children are:
An associative deficit is a problem in associating sounds with their written language. It is possible for a person with an associative deficit to have good sound discrimination but a poor ability to recognise whole words. Although someone with this problem may be able to repeat verbal directions verbatim, they may not have comprehended the message at all. Also, complex sentences are often poorly understood
Auditory decoding deficit
This is the most common problem in children who suffer from APD. Information is processed inaccurately and slowly, and these children are often wrongly described as having a hearing deficiency. Words may be misheard or confused (eg. ‘maths’ and ‘mass’), and rules for grammar and tense are poorly remembered. Many children with this form of APD have poor spelling and reading skills and tend to tire more quickly than most children of the same age.
Auditory decoding deficit may occur in either of the two hemispheres of the brain. A problem in the left hemisphere, the language centre of the brain, causes a child to have trouble distinguishing the difference between similar sounds – for example, ‘p’ and ‘d’. A problem in the right hemisphere causes difficulties in identifying the tone in which a message is given – for example, if the speaker is angry, excited or being ironic .
Auditory integration deficit
Children with this type of APD find it very hard to combine information that is given in more than one medium. This may translate as a problem when a child has to listen to directions and then perform a physical task, such as in a physical education class. It would be easier for someone with this type of APD to watch another person complete the activity and mimic it in that way . These children tend to wait for others to begin a task so they can gauge how to do it themselves .
These children also have problems understanding words as a whole and this leads to poor spelling and word-recognition. Auditory integration deficit describes what happens when the left and right hemispheres of the brain do not communicate well with each other so the relationship between different pieces of information cannot be recognised .
The primary problem for children with this type of APD is with sequenced information. Such information usually comes in the form of step-by-step tasks or directions. Auditory signals are successfully received but are not organised in a meaningful way to enable an appropriate response. This extends to physical organisation such as keeping study notes in order. Tasks that require planning are particularly difficult, and these children also seem to have trouble expressing themselves . An organisational deficit also affects a child’s ability to generate a response to information that is given verbally.
This problem may be more outwardly apparent than any of the others. Children with a prosodic deficit will not modulate their voices to reflect rhythm, tone or stress. Likewise, they are unable to recognise such modulations in other people’s voices. This is a fundamental skill for good communication so this type of APD is commonly accompanied by social problems. Children with this problem also have little understanding or skill in the area of music .
Auditory hypersensitivity (or tolerance-fading memory) describes a feature of APD where background sounds cannot be selectively ignored . A child without APD would be able to listen to a teacher even when people are whispering around him or her. Children with auditory hypersensitivity, however, would be unable to discriminate between the many sources of sound. To put it simply, each sound in the child’s environment is accepted with equal weighting and the child is unable to attend to the desired message.
This becomes especially problematic in school situations where individual differences in receiving messages cannot be attended to as all students receive one set of instructions at the same time. Children with APD will often appear to have ignored the teacher or misunderstood directions and this becomes harder as teachers start giving multiple instructions within the one sentence. Auditory hypersensitivity is diagnosed through a dichotic listening test especially designed to identify this problem . The ability to selectively listen to one source of sound in a busy environment is sometimes referred to as auditory figure-ground awareness.