1. Testing for Central Auditory Processing Disorders
Harvey Dillon
With thanks to:
Sharon Cameron
Helen Glyde
Dani Tomlin
Pia
Gyldenkaerne
Mridula Sharma
Wayne Wilson

2. On the basis of evidence, what should CAPD testing and remediation services consist of?

3. Defining CAPD Do researchers need to define CAPD?
Yes, ……. but a means not an end
Do clinicians need to determine if a client has CAPD?
No, concept too broad to be useful,
Answer will change each time researchers change the definition
What question should clinicians ask?
Helps the discussion about how sounds are processed within the brain
Consider implications for a clinician when the definition is changed …. Has to phone all past clients to let some know they are now no long have CAPD, and that others have acquired it!!!!!

4. A clinician’s question
Does this child have a problem hearing or understanding sound that adversely affects him or her, and that I or anyone else can do something about?
What is the specific nature of the problem?
Is there a specific remediation for that problem?
What general management techniques will minimize its effects?
What tests should I use to determine the child’s problems?

5. Problems with current definitions
Requirement for modality specificity and absence of other problems.
Auditory processing neurons
Deficient auditory skill
Life consequences
Consequent disabilities
Trauma or failure to develop
Hearing loss
Language processing neurons
Deficient language skill
Life consequences
Visual processing neurons
Deficient visual skill
Life consequences

6. Problems with current definitions
2. Arbitrariness of fail criterion
Which tests to include in battery?
How many tests have to be failed, in how many ears, in what combinations?
What is a fail on each test?

7. Impact of criterion on diagnosis of CAPD
Binaural fail
Monaural fail
Wayne Wilson

8. Problems with a Large Test Battery
Impact on child’s attention
(The tests are often very boring!!)
Relevance of the normative data
Statistical implications of presenting multiple tests - inflating Type II error rate.
So …. how do we solve this problem??

9. Possible, but not very good, solutions….
1. Tighten the pass-fail criteria on each test (e.g. 3 SD):
 have to be very aberrant to fail
2. Require that the individual fail more than one test:
 Only logical if CAPD is a “generalized disorder”
3. Repeat any test that produces a failed result:
 Not consistent with normative data
 An inefficient use of time

10. Current approach to CAPD testing
History
Audiometry
Is there a problem
that CAPD
might explain?
Exclude CAPD;
Refer elsewhere No
Detailed test battery
Yes
Test result interpretation
Non-specific remediation
and management:
Classroom placement
FM use
Instruction style
Soundfield amplification
Auditory training software

11. Dealing with problems in understanding speech
Questionnaire / history
Audiometry
Measured disability
Is there a problem
that CAPD
might explain?
Exclude CAPD;
Refer elsewhere No
Master test battery
Yes
Non-specific remediation
and management:
Classroom placement
FM use
Instruction style
Soundfield amplification
Detailed test battery
Test result interpretation leading to
a disorder-specific diagnosis
Disorder-specific remediation

12. Dealing with problems in understanding speech
Questionnaire / history
Audiometry
Measured disability
Is there a problem
that CAPD
might explain?
Exclude CAPD;
Refer elsewhere No
Master test battery
Yes
Non-specific remediation
and management:
Classroom placement
FM use
Instruction style
Soundfield amplification
FPT
Verbal
SPIN
Hi Cont
LiSN-S
High Cue
Detailed test battery
FPT
Hum
SPIN
Lo Cont
LiSN-S
Spatial
Advantage
Talker
Low Cue
Test result interpretation leading to
a disorder-specific diagnosis ?
Closure
skill
deficits
Undiag-
nosed
deficit
SPD
Pitch
deficit
Disorder-specific remediation ?
Top-down
training
LiSN
& Learn

13. What is a fail on one test?
Proportion of children
Test score
Z-score

14. Test score sensitivity relative to functional listening ability
Can estimate from correlation between test scores and functional ability
Questionnaire scores of listening ability
Educational attainment scores
Test A
Test B

15. Test score sensitivity relative to functional ability:
Test A
Test B

16. Criteria for adopting a CAPD test
Test is associated with variation in functional ability
High sensitivity (= ∆ 𝐹𝑢𝑛𝑐𝑡𝑖𝑜𝑛𝑎𝑙 𝑧−𝑠𝑐𝑜𝑟𝑒 ∆ 𝐶𝐴𝑃𝐷 𝑧−𝑠𝑐𝑜𝑟𝑒 )
Deviant results common in clinical population
Attributes tested minimally shared with other tests in battery
Test result indicates specific remediation necessary (and remediation affects real life)
Time taken is small
Test is minimally affected by attention, intelligence, motivation, working memory
Associated with a known anatomical site and neural mechanism

17. Experiment 1 Dani Tomlin current PhD study
Two subject recruitment groups:
Children referred to Uni of Melbourne Audiology Clinic due to suspected APD (n=65)
Teachers, parent, speech pathologist referral
Normative group (n=47)
School enrolment, open invitation
Age range of 7–12 years
Both groups to complete full test battery
Results converted to Z scores (derived using age specific norms)

18. Measures obtained
Dichotic Digits Test (DDT): Binaural integration (Musiek, 1993)
Frequency Pattern Test (FPT): Temporal sequencing (Musiek et al, 1990)
Gaps in Noise (GIN): Temporal resolution (Musiek et al, 2005)
MLD: Binaural interaction (Bellis, 2003)
LiSN-S: Binaural integration – spatial listening ability (Cameron & Dillon, 2006)
Memory CELF-4: Forward and reverse digits
Attention: BrainTrain®: Continuous Performance Test: Sustained auditory and visual attention
Cognition -TONI-4: Nonverbal cognitive assessment
Questionnaires and interview:
Child completed LIFE questionnaire & recorded interview
Parent completed Fisher checklist & written interview
Teacher Evaluation of Auditory Performance (TEAP) & written interview
Academic Performance - NAPLAN & WARP (reading fluency)

19. Relations between questionnaires
Listening Capabilities Score

20. Relations between outcome variables

21. Test score sensitivity relative to functional abilities
Dichotic digits - left
Listening capabilities
Dani Tomlin

22. Test score sensitivity relative to functional abilities
Dichotic digits - left
Listening capabilities
Dani Tomlin

23. Test score sensitivity relative to functional abilities
Dichotic digits - left
Dichotic digits - right
Freq pattern - left
Freq pattern - right
Listening capabilities
Reading fluency
Literacy
Dani Tomlin

24. Test score sensitivity relative to functional abilities
Gaps in noise - left
Gaps in noise - right
Digit span - Forward
Digit span - Reversed
Listening capabilities
Literacy
Reading fluency
Dani Tomlin

25. Test score sensitivity relative to functional abilities
LiSN-S Low Cue
LiSN-S High cue
MLD z score
attention
Listening capabilities
Literacy
Reading fluency
Dani Tomlin

26. Sensitivity: Effect on outcome variable of being 1 SD below the mean on test score

27. FPT results highly correlated between ears

28. Dichotic digit results less correlated

29. Relationships between test scores

30. Correlations – outcomes and test scores
P<0.01
Correlations – outcomes and test scores
Literacy
WARP
Listen Cap
L DD
R DD
L FPT
R FPT
MLD
L GIN
R GIN
LiSN LC
LiSN HC
LiSN SA
DS Fwd
DS Rev
TONI
Att -
0.60
0.77
0.66
0.41
0.49
0.46
0.03
-0.12
-0.07
0.39
0.34
-0.03
0.56
0.67
0.62
0.64
0.47
0.33
0.37
0.00
0.25
0.22
0.21
0.09
0.44
0.51
0.32
Listening Cap
0.26
-0.04
0.14
0.13
0.43
0.15
0.53
0.35
0.08
0.28
0.48
0.27
-0.17
0.11
0.30
0.87
0.12
0.07
0.17
0.29
0.42
0.38
0.19
0.01
0.36
-0.19
-0.08
0.06
0.05
-0.02
0.73
0.02
0.04
-0.09
-0.05
0.18
0.16
0.24
0.59
0.31
0.23
Attention

31. NAPLAN literacy 1 2 3 4 5 6 7 8 9 10 11 12 L DD * R DD L FPT R FPT MLD
L GIN
R GIN
DS Fwd
DS Rev
LiSN LC
LiSN HC
LiSN SA

32. What is affecting listening capabilities?
TONI
0.27
DS Fwd
0.10
Listening capabilities
0.19
LDD
0.10
DS Rev
0.20
N=59
Adj R2 = 0.31
Att

33. What is affecting literacy?
TONI
But only 14 clinic participants with NAPLAN so far.
0.24
DS Fwd
0.30
0.18
NAPLAN Literacy
LDD
0.16
DS Rev
0.29
N=35
Adj R2 = 0.64
Att

34. Importance of the presenting symptoms?

35. Importance of presenting symptoms
MANOVA analysis: p=0.94

36. Importance of presenting symptoms
Response by child
Interpretation by observer
Event
Acts (inappropriately) based on what was heard
Is not very smart
Can’t follow instructions
Child fails to understand an instruction
Asks for repetition of instruction
Poor concentration
Does nothing
Daydreams
Misbehaves
Badly behaved

37. Experiment 2
Pia Gyldenkaerne current PhD study
Children referred to Macquarie Uni Audiology Clinic due to suspected APD (n=119)
Teachers, parent, speech pathologist referral
Age range of 7–13 years

38. Measures obtained
Dichotic Digits Test (DDT): Binaural integration (Musiek, 1993)
Frequency Pattern Test (FPT): Temporal sequencing (Musiek et al, 1990)
Gaps in Noise (GIN): Temporal resolution (Musiek et al, 2005)
MLD: Binaural interaction (Bellis, 2003)
Memory CELF-4: Forward and reverse digits
Attention: BrainTrain®: Continuous Performance Test: Sustained auditory and visual attention
Cognition -TONI-4: Nonverbal cognitive assessment
Questionnaire:
Purpose designed – yes/no answers to 18 questions asking about difficulties in listening and its possible consequences
Academic Performance: WARP (reading fluency)

39. Test score sensitivity relative to functional ability: Reported difficulties and reading fluency
Dichotic digits - left
Dichotic digits - right
Freq pattern - left
Freq pattern - right
Reading speed
Pia Gyldenkaerne and Mridula Sharma

40. Test score sensitivity relative to functional ability: Reported difficulties and reading speed
Gaps in noise - right
Brain Train attention quotient
Brain Train response control quotient
Binaural masking level difference
Reading speed
Pia Gyldenkaerne and Mridula Sharma

41. r > 0.40; p<
r > 0.25; p <0 .01

42. Simple correlation matrix – outcome scores and test scores
Reported Difficulties
WARP
L DDT
R DD
L FPT
R FPT
R GIN
MLD
TONI
BT Attention Quotient -
-0.57
-0.49
-0.24
-0.42
-0.44
0.28
0.11
-0.55
-0.35
0.41
0.20
0.35
-0.33
-0.07
0.50
0.43
0.42
0.49
-0.20
0.01
0.31
0.36
R DDT
0.22
0.23
-0.11
-0.00
0.07
0.27
0.86
-0.28
-0.05
0.34
-0.06
0.33
0.26
-0.02
0.12
0.04

43. Reported Difficulties
No. of predictors
DDT_L_SD
DDT_R_SD
FPT_L_SD
FPT_R_SD
MLD_SD
GIN_R
BT.AttQuot 1 * 2 3 4 5 6 7
No. of predictors
DDT_L_SD
DDT_R_SD
FPT_L_SD
FPT_R_SD
MLD_SD
GIN_R
BT.AttQuot
TONI.Quot 1 * 2 3 4 5 6 7 8

44. Criteria for adopting a CAPD test
Test is associated with variation in functional ability
High sensitivity (= ∆ 𝐹𝑢𝑛𝑐𝑡𝑖𝑜𝑛𝑎𝑙 𝑧−𝑠𝑐𝑜𝑟𝑒 ∆ 𝐶𝐴𝑃𝐷 𝑧−𝑠𝑐𝑜𝑟𝑒 )
Deviant results common in clinical population
Attributes tested minimally shared with other tests in battery
Leads to a specific diagnosis, for which remediation exists, and remediation affects real life functional ability
Time taken is small
Test is minimally affected by attention, intelligence, motivation, working memory, and language ability
Known high reliability and critical differences
Associated with a known anatomical site and/or neural mechanism

45. Comparison of tests against criteria
LiSN-S LC/SA
Dichotic digits
Freq Patt Test
GIN
Digit span fwd
Digit span reverse
MLD
Sens: slope re functional 4 3 2 5 6
Sens: deviant results common 7
Uniqueness re other tests
6.5
2.5 12
Specific diagnosis leading to effective proven remediation
0/10
Time taken
Minimal effect of attention, working memory, intelligence, motivation, language ability
5/15 16 25
Known high reliability and small critical differences 10 ?
Known anatomical site and neural mechanism 1

46. Diagnosis and intervention
Spatial processing disorder
 LiSN & Learn
Auditory working memory (digit span fwd and reverse)
 Memory booster or Cog Med
Any other disorder causing speech in noise difficulties  dichotic digits
 Remote microphone hearing aids (Hornickel and Krauss),
 dichotic training (DIID or ARIA)

47. Thanks for listening