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Nearly all these children lose confidence and end
up feeling insecure. Rather than get real help, they
are criticised or punished. They feel incapable of
overcoming their learning difficulties, unable to
improve. Some may become isolated, withdrawn and
depressed. Others become bored and restless. Rather
than feel incompetent and bored, many will become
disruptive, risk takers or thrill seekers. They can
appear to have difficulties paying attention or following
instructions, and are often misdiagnosed as having
ADHD. To cover up their deficits, some become cynical,
argumentative and even aggressive when criticised
Some of the behavioural symptoms of CAPD
Below is a listing of some of the common behavioural
characteristics often noted in children with CAPD.
It should be noted that many of these behavioural
characteristics are not unique to CAPD. Some may
also be noted in individuals with other types of
deficits or disorders such as attention deficits,
hearing loss, behavioural problems and learning difficulties
or dyslexia. Therefore, one should not necessarily
assume that the presence of any one or more of these
behaviours indicates that the child has a CAPD. However,
if any of these behaviours are noted, the child should
be considered at risk for CAPD and referred for appropriate
testing.
Difficulty hearing in noisy situations
Difficulty following long conversations
Difficulty hearing conversations on the telephone
Difficulty learning a foreign language or challenging
vocabulary words
Difficulty remembering spoken information (i.e.,
auditory memory deficits)
Difficulty taking notes
Difficulty maintaining focus on an activity if other
sounds are present child is easily distracted by
other sounds in the environment
Difficulty with organisational skills
Difficulty following multi-step directions
Difficulty in directing, sustaining, or dividing
attention
Difficulty with reading and/or spelling
Difficulty processing nonverbal information (e.g.,
lack of music appreciation)
CAPD is assessed through the use of special tests
designed to assess the various auditory functions
of the brain. However, before this type of testing
begins, it is important that each person being tested
receive a routine hearing test as outlined above.
An audiologist must rule out any "physical" hearing
problems. The audiologist will assess the ability
of the ear to detect a normal range of frequencies,
from low tones to high tones, without loss of sensitivity.
We make this referral to an associate Audiologist
experienced in assessing children.
The auditory tests that we use to assess central
auditory function fall into two major categories:
Behavioural tests and Electrophysiological tests.
It should be noted that children being assessed for
CAPD will not necessarily be given a test from each
of these categories.
The selection of which test is used will depend upon
a number of factors, including the age of the child,
the specific auditory difficulties the child displays,
the child's native language and cognitive status.
Generally speaking, children under the age of 7 years
are not candidates for this type of diagnostic testing.
In addition, central auditory processing assessments
may not be appropriate for children with significant
developmental delays and cognitive deficits.
Space limitations preclude an exhaustive discussion
of each of the tests used at the clinic. However,
a brief overview of the major test categories is
provided next, along with an abbreviated description
of a few representative subtests that are available
for use in central auditory assessments.
Electrophysiological tests
Electrophysiological tests are measures of the brain's
response to sounds. A special cap with built in sensors
is placed on the head of the child for the purpose
of measuring the electrical activity that arise from
the central nervous system in response to an auditory
stimulus. An auditory stimulus, often a clicking
sound, or two tones of different frequencies are
delivered to the child's ear and the electrical responses
are recorded.
Some evaluate processing low in the brain (auditory
brainstem response), whereas others assess functioning
higher in the brain (middle latency responses, late
auditory evoked responses, auditory cognitive or
P300 responses). The results obtained on these tests
are compared to age-appropriate norms to determine
if any abnormalities exist.
Behavioural tests
Auditory Sceening and Preliminary Assesment
Procedures
SCAN: A Screening Test for Auditory Processing Disorders.
Keith, R.(1986).
SCAN is used to identify
children who have auditory processing disorders and
who may benefit from intervention. The test is administered
to children ages 5 to 11 in approximately 20 minutes.
Three subtests include low pass filtered words, auditory
figure ground and competing words.
The SCAN
A: A Test for Auditory Processing Disorders in Adolescents
and Adults was designed for individuals over 11 years.
This instrument includes an additional subtest using
competing sentences as stimuli.
Monaural Low-Redundancy Speech Tests
Due to the richness of the neural pathways in our
auditory system and the redundancy of acoustic information
in spoken language, a normal listener is able to
recognise speech even when parts of the speech signal
are missing. However, this ability is often compromised
in the individual with CAPD. Monaural low-redundancy
speech tests represent a group of tests designed
to test an individual's ability to achieve auditory
closure when information is missing. The speech stimuli
used in these tests have been modified by changing
one or more of the following characteristics of the
speech signal: frequency, timing (phase), or amplitude
characteristics. The test items are presented to
each ear individually and the child is asked to repeat
the words that have been presented. A percent correct
score is derived for each ear and these are compared
to age-appropriate norms.
Dichotic Speech Tests
In these tests different speech items are presented
to both ears either simultaneously or in an overlapping
manner and the child is asked to repeat everything
that is heard (divided attention) or repeat whatever
is heard in one specified ear (directed attention).
The more similar and closely acoustically aligned
the test items, the more difficult the task.
One of the more commonly used tests in this category
is the Dichotic Digits test. The child is asked to
listen to four numbers presented to the two ears
at comfortable listening levels. In each test item
two numbers are presented to one ear and two numbers
are presented to the other ear. For example, in figure
one, 5 is presented to the right ear at the same
time 1 is presented to the left ear. Then the numbers
9 and 6 are presented simultaneously to the right
and left ears. The child is asked to repeat all numbers
heard and a percent correct score is determined for
each ear and compared to age-appropriate norms. |
