Auditory processing disorders, reading deficits and dichotic perception

Auditory processing disorders, reading
deficits and dichotic perception
Sharon Cameron, Harvey Dillon, Kiri Mealings
John Seymour, Jessica Whitfield, Taegan Young
National Acoustic Laboratories
CHSCOM2017
Linkoping
July 2017
A talk in two parts
Auditory processing disorders and reading
Auditory
processing
Dichotic perception: what is being measured
Reading deficit
LiSN-S
Spatial
processing
disorder
LiSN & Learn
Sound Storm
?
Dichotic deficit
Digit span forward
and reverse
Dichotic Digit Test
Dichotic deficits
Memory
Memory
Booster
Wireless
remote
microphone
Dichotic training
ARIA, DIID
Types of Reading Disorders: The Castles and Coltheart Test 2 (CC2)
Deficits with words that
must be learned by sight:
Deficits with words that
are learned by
“sounding out”:
• Unfamiliar regular
words (ligneous)
• Non-Words (lenk)
• Irregular Words (yacht)
Phonological
Dyslexia
(Sub-lexical
route)
24%*
< -1 SD applied
Mixed
Dyslexia
Surface
Dyslexia
(Lexical
route)
56%*
20%*
McArthur et al., 2013
4
Hypotheses
Auditory
Deficit
Phonological
Dyslexia
Speech sounds analysed with sufficient resolution:
•
•
Rapid formant transitions (Tallal)
Rise time and modulation detection (Goswami)
Internal templates of these sounds become unclear, or
“fuzzy”, potentially impacting letter-sound matching.
Manifests behaviourally as:
• poor categorical perception of plosive speech
sounds (PIT), or
• poor perception of syllable boundaries (ParSE).
5
Phoneme Identification Test (PIT)
• Purpose:
Measures the precision of
categorical perception of
stop consonants
• Stimuli:
92 /ba/ and /da/ tokens.
• Variation:
F2 changes along an 11-step
continuum from 100% /ba/
to 100% /da/.
• Test Conditions:
Quiet and Noise (0 dB SNR)
• Response:
Participant presses BA or
DA button depending on
what phoneme they heard.
6
/da/ responses (%)
Typical
PIT
Results
100% /ba/
ILTASS Filtered
White Noise
100% /da/
PIT “Ambiguous Region” – TD vs Phonological Dyslexia
Typically Developing Child
Child with Diagnosed Phonological Dyslexia
8
Parsing Syllable Envelopes (ParSE) Test
9
Typical
ParSE
Results
UBUR:
Upper Bound of the
Uncertainty Region
0%
AM
50%
AM
100%
AM
ParSE “Ambiguous Region” – TD vs Phonological Dyslexia
Typically Developing Child
Child with Diagnosed Phonological Dyslexia
11
Results: 1. Normative data – Phoneme Identification Test
Uncertainty region in quiet
Uncertainty region in noise
12
Results: 2. Normative data – Parsing syllable envelope test
13
Results: 3. Relation to reading ability
n=16!
14
Child with
reported
reading
difficulties:
What type?
Test: CC2
Fail non-words
Phonological
dyslexia
N=4
Auditory
deficit?
Test: PIT &
ParSE
Fail non-words
and irregular
words
Auditory
deficit?
Mixed dyslexia
Test: PIT &
ParSE
N=6
Auditory deficit
Pass (≥ -1 SD):
Other deficit
Fail (<-1.67 SD):
Auditory deficit
Pass (≥ -1 SD):
Other deficit
Fail (<-1.67 SD):
Fail irregular
words
Control Group
Surface dyslexia
Test: PIT & ParSE
N=6
Fail (< -1.67 SD):
Against hypothesis
Pass (≥ -1 SD):
As hypothesized
n=4
n=0
5 Pit
3 Parse
n=4
n=2
n=1*
Parse
n=4
15
Child with
reported
reading
difficulties:
What type?
Test: CC2
Fail non-words
Phonological
dyslexia
N=4
Auditory
deficit?
Test: PIT &
ParSE
Fail non-words
and irregular
words
Auditory
deficit?
Mixed dyslexia
Test: PIT &
ParSE
N=6
Auditory deficit
Pass (≥ -1 SD):
Other deficit
Fail (<-1.67 SD):
Auditory deficit
Pass (≥ -1 SD):
Other deficit
Fail (<-1.67 SD):
Fail irregular
words
Control Group
Surface dyslexia
Test: PIT & ParSE
N=6
Fail (< -1.67 SD):
Against hypothesis
Pass (≥ -1 SD):
As hypothesized
n=4
Trial WRM
n=0
n=4
Trial WRM
n=2
n=1*
n=4
16
Dichotic Testing
What is it testing?
National Acoustic Laboratories, Sydney, Australia
Existing dichotic tests
•
Dichotic paradigms are the most commonly used
tests in CAPD batteries.
1, 8
2, 4
•
Intended to assess binaural interactions
•
Dichotic Digits Test (DDT) results correlate with
academic outcomes and listening difficulty.
1, 2, 4, 8
18
Testing
cognitive
ability
Dichotic
tests
•
•
•
•
•
Selective attention
Working memory
Executive function
Aging
Mental Retardation
Application
to splitbrain
patients
Information
about
hemisphere
differences
Application to
auditory processing
disorder patients
Inferences
about
auditory
processing
Cognitive
deficits
Brain “lesions” in
Central Auditory
Nervouse System
Cause
Indicate
Low dichotic
test scores
National Acoustic Laboratories, Sydney, Australia
The Dichotic Digits difference Test
Cameron et al. (2016; JAAA)
(DDdT)
•
Modified version of the DDT
•
Four different test paradigms:
•
Dichotic free recall
•
Dichotic directed left & right
•
Diotic
•
Computer scored
•
Norms based on exact age
22
National Acoustic Laboratories, Sydney, Australia
Dichotic Free Recall Paradigm
2, 4
1, 8
1, 2, 4, 8
23
National Acoustic Laboratories, Sydney, Australia
Diotic Paradigm
2, 4
1, 8
2, 4
1, 8
2,4,1,8
24
Interpreting results
Diotic Recall
Dichotic Free Recall
Right ear advantage (free)
2, 4
2, 4,
1, 8
1, 8
2, 4,
1, 8
Dichotic advantage
1, 2, 4, 8
1, 2, 4, 8
Dichotic Directed Left
Dichotic Directed Right
2, 4
1, 8
2, 4
1, 8
Right ear advantage (dir)
1, 8
2, 4
25
The participants
Group
N
Digit
span
Attention
TONI
Life
Fishers
School W Typically developing
50
50
50
50
50
50
School S – Typically
developing
62
-
-
-
-
-
Adults – Typically
developing
10
-
-
-
-
-
CAPD clinics
103 children;
13 adults
116
93
9
10
-
10
Total
238
143
59
60
60
Clinic
School
100
90
r = 0.82
80
Diotic (%)
Dichotic
versus
diotic
(%)
70
60
50
40
30
30
40
50
60
70
80
Dichotic free recall (%)
90
100
Directed
right
Free-recall
right
N=70
Free-recall
left
Directed
left
28
2
1
Diotic (z score)
Dichotic
versus
diotic
(z score)
Clinic
School
r = 0.78
0
-1
-2
-3
-4
-5
-5
-4
-3
-2
-1
0
Dichotic free recall (z score)
1
2
Correlations
Attention
(prudence)
0.26
Attention
(vigilence)
Forward digit
span
Reverse digit
span
0.15
0.52
Diotic
0.42
0.24
Non-verbal IQ
Correlations
Attention
(prudence)
0.31
Attention
(vigilence)
Forward digit
span
Reverse digit
span
0.21
Free recall
dichotic
0.53
0.36
0.27
Non-verbal IQ
Correlations
Attention
(prudence)
0.22
Attention
(vigilence)
Forward digit
span
Reverse digit
span
0.12
Directed
dichotic
0.26
0.02
0.21
Non-verbal IQ
3
2
Dichotic free recall (z score)
Dichotic
scores
and
memory
Clinic
School
1
0
-1
-2
-3
-4
-5
-3
The normal range!
-2
-1
0
1
2
3
Number memory forward (z score)
36
Multiple regression
Diotic
0.70
Dichotic
R = 0.80
R2 = 0.64
0.17
Forward digit
span
What about the other 36% of variance?
Random
measurement
error
Accounting
for
variance
9%
27%
Dichotic
test scores
Memory
64%
Other
non-dichotic
factors
Dichotic
factors
64%
+27%
91%
What about strong left-right asymmetries?
An analogy
Percent correct
100%
3
+4
?
3,148
-1,659
?
0%
Cognitive resources applied to task
An analogy
Percent correct
100%
Right
Left
0%
Cognitive resources applied to task
National Acoustic Laboratories, Sydney, Australia
Conclusions

Scores on the commonly-used double-digit dichotic test are hugely
influenced (~ 64% of variance) by abilities unrelated to dichotic
perception.

Measurement error accounts for ~ 27% of variance.

Across the clinical and typically developing population studied, dichotic
issues play a relatively small role (~ 9% of variance) in determining the
scores obtained on these dichotic tests.

What is the implication for how “dichotic deficits” should be
remediated?
42
National Acoustic Laboratories, Sydney, Australia
Support of the Australian Department of Health is greatly appreciated.
www.NAL.gov.au
43
Effect of random measurement error
100%
90%
90%
Example:
R
80%
8 yr old: L=79%; R=88%
70%
Observed score
70%
L
60%
50%
40%
30%
20%
asymmetry
20%
10%
0%
0%
10%
20%
30%
40%
50%
True score
60%
70%
80%
90%
100%
Dichotic deficit
≡ dichotic score – diotic score
(normalised for age)
Left
Right Total
Free recall dichotic
34%
25%
Directed dichotic
65%
60%
Diotic
29%
46%
Dichotic advantge (z score)
4
Clinic
School
3
2
1
0
-1
-2
-3
10
30
20
Age
50
40
70
60
80