Presentation at course on Auditory Processing, Language and Cognition. Ear Institute, UCL. March 2018

1. 1
Developmental language disorder
and auditory processing disorder:
Same or different?
Dorothy V. M. Bishop
Department of Experimental Psychology,
University of Oxford

2. Overview of talk
Using my own research to illustrate some key points about
overlaps between APD, DLD, dyslexia
• Studies comparing those with different diagnoses
– Children diagnosed with APD often have language problems
– Children diagnosed with DLD/dyslexia often have auditory
problems
• Can we devise auditory processing measures that aren’t
affected by language measures?
– No! Even passive electrophysiological measures can be
influenced by language
• Can we confirm that auditory deficit has causal role?
– Causal models suggest apparent APD can be consequence of
language disorder
– No good evidence that auditory interventions benefit language 2

3. Part 1
Evidence that the same child may have features of APD,
DLD, dyslexia, ADHD or autism spectrum disorder
Specific diagnosis may depend on who they see
3

4. Hypothetical 9-yr-old: George
4
• Late to start to talk
• Episodes of otitis media with effusion
as a toddler
• Otherwise developed normally
• Now struggling at school
• Doesn’t always remember what his
teacher says
• Complains that people talk too fast
for him to understand
• Parents think he may have APD and
seek referral to audiologist

5. Audiological evaluation
5
• Normal peripheral hearing
• Low score on competing words
dichotic listening (SCAN-3)
• Low score on auditory figure-
ground

6. Psychological/language
assessment
6
• Nonverbal IQ of 103
• Vocabulary and comprehension
levels are lower, with scaled score
equivalents of 85
• Poor scores on tests of verbal
memory
• Reading ability is at a 7-year-old
level

7. George’s diagnosis depends on
who makes it
7
Same child diagnosed with:
• Auditory Processing Disorder (APD) by
audiologist
• Developmental Language Disorder
(DLD)* by speech/language therapist
• Developmental dyslexia by educational
psychologist
* Previously referred to as Specific Language Impairment (SLI)
Is this anecdote backed up by data?

8. Study comparing children diagnosed with
APD vs those diagnosed with dyslexia
25 children with APD diagnosis
• recruited from audiology clinics based at four hospitals in the UK. All
of these children had been diagnosed on basis of
– complaint of listening difficulties,
– normal peripheral hearing
– score below clinical cut-off on the SCAN-C or-A9 10 plus
– failed on at least one non-speech test of auditory processing
19 children diagnosed with dyslexia by educational psychologist
– reading or spelling test standard score > 1 SD below mean
– non-verbal IQ greater or equal to 80
• Direct assessments of language and literacy, SCAN-C
• Parent questionnaires: language, behaviour, listening, autistic
features
8Dawes & Bishop (2010) Psychometric profile of children with auditory processing
disorder and children with dyslexia. Archives of Disease in Childhood, 95, 432-436.

9. • Parent rating of communication on CCC-2 was also surprisingly
low, suggesting autistic features;
• Subset given Childhood Asperger Syndrome test; 6/18 APD and
0/12 dyslexic above threshold for ‘possible clinical case’
9
Percentages meeting diagnostic criteria
APD
N = 25
Dyslexia
N = 19
Developmental
Language
Disorder 52% 58%
ADHD
37% 46%
APD (borderline+
on SCAN) 40% 22%

10. Conclusions:
APD vs dyslexia
Surprisingly small number of APD cases did poorly on SCAN-C – we
used own UK norms. Concern that current test batteries may over-
diagnose APD
Considerable overlap in symptoms – variable neurodevelopmental
problems in both groups.
Parent report of communication problems was high, even taking into
account language/literacy test scores: Autistic-like communication
problems related to APD
APD more like a variable correlate of neurodevelopmental disorders
(including DLD, dyslexia, ADHD, ASD) than a distinct syndrome
10

11. Does specific diagnosis matter?
Yes. Has implications for intervention
11

12. 12
Auditory
processing
disorder
Poor speech discrimination
Broader language
deficits
Implicit in diagnosis of APD:
Language/literacy problems as downstream
consequence of low-level perceptual deficit
Intervention

13. Auditory processing
Phonetic feature
extraction
Phonological
analysis
Word recognition
13
Typical ’bottom-up’ model of auditory/phonological processing
Bishop, D. V. M. (1997) Uncommon understanding: Development and disorders of
language comprehension in children

14. Auditory processing
Phonetic feature
extraction
Phonological
analysis
Word recognition
14
Phonological processing influenced by top-down knowledge
Higher-level
language
knowledge

15. Fail auditory
processing
tests
Poor language skills
Alternative possibility

16. Fail auditory
processing
tests
Poor language skills
Suggests auditory intervention won’t be effective in
improving language: Need direct language
intervention
Intervention

17. Part 2
Can we develop pure measures?
17

18. Can we devise auditory measures
that are not contaminated by
language level?
Many APD tests hard to interpret
• Use of verbal stimulus materials
– Poor performance could be result of limited language skills
• Verbal strategies with nonverbal tasks
– Implicit or explicit verbal labelling of stimuli
18

19. -
P1 N1 P2 N2+
FZ
100 ms
1 µV
An alternative approach: Electrophysiological
rather than behavioural measures
• More direct measure of brain response
• Passive paradigm: Less likely to be influenced by motivation,
strategy, etc
• But: Cannot assume ERPs won’t be affected by prior language
experience (as I will show later!)
Auditory ERP (event-related potential)

20. Other disadvantages of auditory ERPs
Lack good psychometric properties:
• Little known about what is typical at given age
(means/variances)
• Some indices have poor reliability (especially
with children – but seldom tested)
• Little consistency across labs
• Seldom correlate with behavioural measures

21. Conclusions from a review of mismatch
negativity and language/literacy problems
Scope for ‘false positive psychology’
• Post hoc decisions re:
• Which electrode(s) to use
• Which time window
• How to filter
• Artefact rejection
• Averaging or peak measurements
Simmons, J. P., Nelson, L. D., & Simonsohn, U. (2011). False-positive psychology:
undisclosed flexibility in data collection and analysis allows presenting anything as
significant. Psychological Science, 22(11), 1359-1366.
Bishop, D. V. M. (2007) Using mismatch negativity to study central auditory processing
in developmental language and literacy impairments: where are we, and where should
we be going? Psychological Bulletin, 133, 651-672

22. 22
If we are going to develop a
clinically-useful ERP measure,
need to focus on findings that
are replicable across labs and
samples

23. 23
A candidate for an auditory ERP
component that is related to
language disorder and seems to
replicate:
the T-complex

24. • T-complex: AERP recorded from temporal sites ; generated in secondary
auditory cortex,
• Lateralised with a right-sided predominance
• T-complex has a different developmental trajectory to the vertex response
• Matures early and remains relatively constant from puberty onwards

25. Shafer, Schwartz & Martin, 2011
Experiment 1: 12 typically developing vs 8 DLD (SLI)

26. Shafer, Schwartz & Martin, 2011
• Re-analysis of data from four ERP studies on
DLD
• Stimuli: words or vowel sounds
• 22 children with DLD, 31 typically-developing
controls
• Absent/weak T-complex in 73% DLD vs. 13%
typical
Seemed worth looking at T-complex in our data

27. Mervyn
Hardiman
Can we replicate T-complex abnormality in DLD, and if so, is it specific to
speech stimuli?
Stimuli: 1000 Hz tone or /ba/ syllable, both 175 ms
Johanna
Barry

28. Participants
• 32 children aged 7 to 11 yr
• 16 with DLD
• 16 matched TD controls
• 32 teenagers aged 12 to 15 yr
• 16 with DLD
• 16 matched TD controls
DLD and typically developing (TD) matched on age, sex and nonverbal IQ

29. ERP at temporal sites: 1000 Hz tone: reduction in T-complex in
DLD children and teens (grey) vs controls (black)
Children
Teens
TD
DLD
LEFT RIGHT

30. ERP at temporal sites: Syllable ‘ba’: Large reduction in T-
complex in DLD
Children
Teens
TD
DLD
LEFT RIGHT

31. Categorical classification
• Tone condition:
– 8 TD cases vs 17 DLD cases had no Ta
• Speech condition
– 8 TD cases vs 20 DLD cases had no Ta
• Similar to Shafer et al: Highly significant difference, but
absence of Ta is not a reliable marker for DLD;
• Cases of no Ta in controls raises question about whether
absent Ta reflects cause of language disorder

32. 32
Does T-complex predict
children’s language skills?

33. Test for Reception of
Grammar
The elephant pushing the boy is big
Receptive and phonological measures selected as most likely to
relate to auditory ERP

34. Test for Reception of
Grammar
The elephant pushing the boy is big
NEPSY nonword repetition
Child repeats nonwords
presented by audio recording
e.g. skriflunaflisstrop
detratapillic
Scored by N syllables correct
Receptive and phonological measures selected as most likely to
relate to auditory ERP

35. Test for Reception of
Grammar
The elephant pushing the boy is big
NEPSY nonword repetition
Child repeats nonwords
presented by audio recording
e.g. skriflunaflisstrop
detratapillic
Scored by N syllables correct
NEPSY
oromotor sequences
Repeat ‘tongue-twisters’
five times each
e.g. “scoobelly doobelly”
“put the pepper beads in the paper bag”
Receptive and phonological measures selected as most likely to
relate to auditory ERP

36. Test for Reception of
Grammar
The elephant pushing the boy is big
NEPSY nonword repetition
Child repeats nonwords
presented by audio recording
e.g. skriflunaflisstrop
detratapillic
Scored by N syllables correct
NEPSY
oromotor sequences
Repeat ‘tongue-twisters’
five times each
e.g. “scoobelly doobelly”
“put the pepper beads in the paper bag”
TOWRE
phonemic decoding
Speeded reading of
nonwords
Receptive and phonological measures selected as most likely to
relate to auditory ERP

37. Does Ta amplitude predict
language/literacy?
1 2 3 4
1 Tone T7 1
2 Tone T8 0.66 1 .
3 Syllable T7 0.63 0.44 1
4 Syllable T8 0.36 0.66 0.56 1
5 TROG-2 0.07 0.03 0.24 0.08
6 Nonword rep 0.25 0.32 0.31 0.37
7 Nonword read 0.22 0.29 0.36 0.31
8 Oromotor 0.18 0.20 0.36 0.27
z-scores (age corrected)
Correlations in orange show that the T complex measures tend to be intercorrelated
Yellow correlations are significant associations between T complex measures and
language measures

38. Part 3
Distinguishing causal relationships
38

39. Poor T-complex
Poor language skills
But correlation does not indicate direction of
causation
B
Poor T-complex
Poor language skills
A
T-complex may arise as
brain becomes proficient in
language learning

40. 40
PLoS ONE 12(3): e0171992.
doi:10.1371/journal.pone.0171992
The results revealed differences in temporal AEPs (Na and
Ta of the T-complex) between monolingual and bilingual
children. Specifically, bilingual children showed smaller
and/or later peak amplitudes than the monolingual groups.
….Amount of experience and type of experience with the
target language (English and German) influenced
processing.
Evidence that T-complex can be affected by language experience

41. 41
Correlation between parent LI and child LI = x.y
If x = 0, then predict no parent/child covariance
Indexed by
parental
language
scores
Indexed by
Ta component
of auditory ERP
in child
Indexed by
child language
scores
We can help disentangle cause by considering data on parental language

42. 42
Language disorder tends to be familial:
parent and child language correlated

43. 43
Parent Tone L Tone R Syll L Syll R
9 TROG-2 0.14 0.12 0.08 0.00
10 Nonword rep 0.13 0.14 0.06 0.12
11 Nonword read 0.11 0.13 0.11 0.09
12 Oromotor 0.30 0.38 0.30 0.41
Child auditory ERP, Ta
Correlations between child Ta and
parent language measures
Parent language measures that correlate with child
language don’t correlate with child auditory ERP:
Endophenotype model does not fit

44. 44
If abnormal Ta (auditory deficit) is a consequence of language disorder
Covariance between parent LI/child auditory = y.z;
Will be small but positive
Parent measure Child measures
A different causal model …..

45. 45
POOR FIT
POOR
FAIR
GOOD FIT
Pattern of correlations fits
Neuroplasticity model better than
Endophenotype – i.e. looks as if T-
complex abnormality may be a
marker of poor language, but not a
cause

46. T-complex study: conclusions
• Replicated abnormal T-complex in SLI
• Topography as well as amplitude abnormal for syllable
‘ba’
• Inclusion of parental data provides way of testing
between causal models
• In this dataset, results gave best fit to model in which
language impairment influenced how brain responds to
auditory signals
• Even a passive, neurophysiological measure may be
influenced by language ability

47. What would be evidence for
auditory causal model?
• Show that auditory-focused intervention
improves language skills
47

48. 48
Auditory intervention for
language problems
• Fast transitional elements amplified and stretched
 FastForWord® - computerised training
– Developed by Tallal and colleagues;
– Very intensive; 90 min x 5 day/wk x 6 wk
– Uses speech that is modified to make brief/low
intensity portions more salient

49. 49
FastForWord® : studies of effectiveness
Meta-analysis combining results from six high-
quality trials found FFW group did no better than
control group
“None of the 8 pooled effect sizes were reliably
different from zero, and 4 of the effect sizes were
actually negative (indicating worse performance
in the Fast ForWord treatment group than the
control group).”
Strong, G. K., et al. (2010). A systematic meta-analytic review of evidence for the
effectiveness of the ‘Fast ForWord’ language intervention program. Journal of Child
Psychology and Psychiatry, 52(3), 224-235.

50. Might auditory manipulation still
be effective?
 Auditory training is only part of the FFW package
 Some children who were given the intervention
had no problems with auditory discrimination

51. Bishop, Rosen & Adams, 2006
Questions
• Can computerised training improve comprehension in
children with receptive language problems?
• If so, does speech modification help?
• Does child’s auditory processing status make a
difference?
Bishop, D. V. M., Adams, C. V., & Rosen, S. (2006). Resistance of grammatical
impairment to computerized comprehension training in children with specific and non-
specific language impairments. International Journal of Language and Communication
Disorders, 41, 19-40.
Stuart Rosen
UCL
Caroline Adams
Oxford

52. Design of study
Group S: trained with regular speech
Group M: trained with modified speech
Group U: untrained
• Language assessment
• Auditory discrimination test
• Comprehension training (less intensive than FFW)

53. • Game measures ability to distinguish direction of tone glides
• Difficulty increased by making sounds closer in frequency
• Adaptive threshold estimation; unpaced presentation

54. Comprehension training

55. Child hears sentence and must move objects on screen to match.
Fast/correct responses rewarded with exciting feedback

56. Amount of training
group S
N = 12
group M
N = 12
sessions: mean (SD) 14.50 (7.57) 16.00 (7.90)
range 6-26 6-29
trials: mean (SD) 1162 (847) 1162 (646)
range 243-2529 289-2191
Normal Modified
speech speech

57. Time 2 : retest
• Average of 80 days after time 1
• Same battery of standardized language
tests
• Parallel forms used

58. TROG-2 scores
50
55
60
65
70
75
80
85
Group S
N = 12
Group M
N = 12
Group U
N = 9
drop-out
N = 3
scaledscore
pretest
posttest
• All groups improved;
• No effect of training or speech modification
• Improvement unrelated to amount of training
• Improvement unrelated to initial auditory scores

59. What have we learned?
• Many children with receptive language disorders don’t have
the auditory processing problems postulated by Tallal’s
theory
• No relationship between auditory impairment and learning
• On a task that doesn’t tax auditory perception, learning
occurs but it is very very slow. Suggests main problem is
with language learning processes, rather than auditory
processing

60. Overview: Implications for APD
• Classic APD measures may not be measuring
primary auditory deficit
• APD is a symptom: not a coherent syndrome
• Need to consider top-down impact of language
disorder on test performance – even when
electrophysiological measures are used
• Intervention studies: hard to interpret unless
properly controlled trials
• As yet no convincing evidence from double-blind
RCTs that training in auditory processing
improves language skills 60

61. Recommendations
• Need for better, well-validated, reliable APD tests with
local norms. Reliance on currently-available tests risks
over-diagnosis
• Complement APD assessment with language, literacy,
communication, assessments. What looks like ‘listening
problems’ may be high-level comprehension problems
• Need for multidisciplinary working
61

62. 62
Dorothy Bishop
Oxford Study of Children’s Communication
Impairments,
Department of Experimental Psychology,
South Parks Road,
Oxford,
OX1 3UD,
England.
dorothy.bishop@psy.ox.ac.uk
http://www.psy.ox.ac.uk/oscci/