Assessment of Central Auditory Processing Disorders: Which tests

1
Assessment of Central Auditory Processing
Disorders Which tests?

• Suzanne C Purdy
• National Acoustic Laboratories, Sydney, Australia
• and
• Caroline Johnstone
• National Audiology Centre, Auckland, New Zealand

Presented at New Zealand Audiological Society
Conference, Rotorua, NZ, 3-5 Aug 2000
2
Topics

• ASHA Task Force (1996) approach
• Problems highlighted recently
• Preliminary analyses of CAPD assessment data from
  National Audiology Centre
• Dichotic Digits test
• Frequency Patterns test
• CHAPPS questionnaire

?
two of Frank Musieks favourite tests
3
ASHA Task Force on Central Auditory Processing
Consensus Development, July 1996

• Consensus has been lacking on precisely how to
  define central auditory processing and its
  disorders and how the disorders can be identified
  and ameliorated through intervention

4
Task Force recommended that diagnosis of CAPD
should be based on a number of indices

• history (family history, speech language. . )
• systematic observation of auditory behaviour
  using questionnaires or checklists
• audiological test procedures including pure tone,
  speech and immittance audiometry
• speech-language pathology measures

5
Task Force recommended that diagnosis of CAPD
should be based on a number of indices ctd

• tests of central processes
• temporal
• localization and lateralization
• low redundancy monaural speech
• dichotic stimuli (binaural integration and
  separation)
• binaural interaction procedures

6
Evidence-based Practice

• . . . means clinicians use evaluation and
  treatment procedures based on data published in
  peer-reviewed journals and that the data indicate
  the effectiveness of the procedures for
  particular disorders and populations.

Jeri Logemann, ASHA Leader, March 14, 2000
7
Critical Review of CAPD Literature by Cacace and
McFarland (1998)
. . The existing literature on this topic has
not clarified the true nature of the problem,
and has left many questions about this disorder
unanswered.
8
Test Battery Approach Questioned by Singer et al
(1998)

• N147 children with a classroom learning
  disability and presumed CAPD
• Reading problems, difficulty following verbal
  direction and paying attention in class
• Computed sensitivity, specificity, A (diagnostic
  value)
• False positive rate (specificity) similar across
  the 7 tests and 5 age groups (10-12)

9
Test Battery Approach

• Binaural Fusion Test, Masking Level Difference,
  Filtered Speech Test, Time Compressed Speech,
  Dichotic Digits, Staggered Spondaic Words, Pitch
  Pattern Test

Hit Rates
Singer et al, 1998
10
Testing with Marshmallows

• Case 1 9 yr old Competing Sentences (1)
  40/60, (2) 0/60, (3) 100 with roasted
  marshmallows
• Case 2 10 yr old Filtered Speech
  (1) 60/42, (2) 64/28, (3) 84/80 with quarters
• Case 3 8 yr old Competing Filtered Words (1)
  3/3, (2) 3/3, (3) 9/10 Raw Score with baseball
  cards

Silman et al, 2000
11
What is a good test?

• Sensitivity
• Specificity
• Positive Predictive Power
• Intra- and Inter-subject Reliability

?

• Problem lack of a gold standard

12
What is a good test?

• Quick and easy to administer
• Produce a range of scores
• Not all children fail / not all children pass
• Validity
• shows expected maturation effects
• shows expected ear advantage in young children
• correlates with behaviour

13
Central auditory processes are the auditory
system mechanisms and processes responsible for
the following behavioural phenomena

• sound localization and lateralisation
• auditory discrimination
• auditory pattern recognition
• temporal aspects of audition
• temporal resolution, masking, integration,
  ordering
• auditory performance decrements with competing
  acoustic signals
• auditory performance decrements with degraded
  acoustic signals

14
Dichotic Speech Tests
green house string bean
Frequency Pattern Tests
High Low High Low High High Low Low High Low High
Low
15
Mean Dichotic Digit and Frequency Pattern Scores
N
16
Are DD and FP good tests for 8 and 9 year olds?

• DD and FP tests produce a range of test scores
  with few children scoring 100
• DD and FP tests show the expected right ear
  advantage
• FP test shows the expected maturational
  improvement

17
Childrens Auditory Processing Performance Scale
(CHAPPS)

• Compare amount of difficulty to other children of
  similar age and background in 6 areas
• 7-point scale (1, 0, -1, . . , -5)
• 3 listening only subscales difficulty hearing
  and understanding in Noise, Quiet, Ideal
  conditions
• Multiple Inputs (listening visual, etc)
• Auditory Memory/sequencing
• Auditory Attention Span

18
Mean CHAPPS Ratings
19
Parental CHAPPS ratings of 8 year olds who passed
(mean 89) vs failed (mean 68) the Double
Dichotic Digit Test
20
Parental CHAPPS ratings of 8 year olds who passed
(mean 71) vs failed (mean 2) the Frequency
Patterns Test
21
Is the CHAPPS a good questionnaire?

• Ratings are poorest for difficult listening
  situations
• 8 year olds are poorer than 9 year olds for 5 of
  the 6 subscales
• CHAPPS ratings poorer for 8 year olds who fail DD
  for 5 of the 6 subscales
• CHAPPS listening only ratings poorer for 8 year
  olds who fail FP

22
CHAPPS ratings of 8 year olds who failed both
tests, Frequency Patterns only, Dichotic Digits
only, or who passed both tests
23
CHAPPS ratings of 9 year olds who failed both
tests, Frequency Patterns only, Dichotic Digits
only, or who passed both tests
24
Test failure patterns of 8 versus 9 year olds
25
8 and 9 year olds appear to be presenting with
different problems

• As expected 9 yrs better than 8 yr olds at FP
• 8 and 9 yr olds perform the same on DD test, so
  more 9 yr olds fail
• For all but one area 9 yr olds have fewer
  problems than 8 yr olds, as expected with
  maturation
• Parents report more Auditory Memory/Sequencing
  problems in 9 yr olds

26
Dichotic Digits vs CHAPPS memory for 8 (n20) and
9 (n12) year olds (p.010)
27
Performance on DD test related to CHAPPS Memory
ratings

• 9 yr olds have more problems with DD than 8 yr
  olds
• 9 yr olds rated as having more Auditory Memory
  problems than 8 yr olds
• DD scores significantly correlated with CHAPPS
  Memory ratings (but not Noise)

28
Conclusions

• Different tests (battery approach) may be helpful
  in identifying different patterns of auditory
  processing difficulties
• Data suggest that different test(s) needed for
  different age groups
• Preliminary analyses support the use of the DD
  and FP tests and CHAPPS
• Much more work is needed