making_the_links_in_diagnostic_assessment_

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Making the links
Dr Anna Smith
No task is ‘pure’
• Neuropsychological
functions operate together
rather than in isolation
• Theoretically, a pure task
would lack ecological
validity
• We need to examine
evidence
• Certainty is not guaranteed
No single diagnostic test
• Dyslexia is heterogenous
• No different from other
developmental disorders
• eg., ADHD is diverse
with several:
 Etiological pathways
 Clinical presentations
 Levels of severity
Two cases of ADHD
Case 1: Dan (12)
• Born prematurely
• low scores on target
detection tasks
• Academically
underachieving
• Easy to manage
Case 2: Sian (41)
• Talks continuously and
changes subject
• Difficulty keeping job for
very long
• Several relationships in
succession
• Impulsive hobbies that
don’t last long
• Performance is average
on most tasks
Dyslexia is also heterogenous
• Dyslexia can be heterogenous
• We must make judgement on the
neuropsychological evidence we
have gathered
 Test scores
 Background information
 Qualitative information during
assessment
• A good assessor will make the
links
Reading
• Comparison of reading single words and
reading in context
 Higher scores in tests of comprehension
suggest inference when reading in context
• Comparison of timed and untimed
reading of single words with WRAT and
TOWRE 2
 poor reading fluency is more likely to be
observed in older children and adults
• Comparison with PA subtests
 Errors on phonetically plausible words
suggest phonological deficits
Spelling
• Good readers can be poor spellers
 They tend to make ‘phonetic’ errors eg., spelling cough, as coff
 Poor readers and poor spellers make more ‘non-phonetic’
errors eg, spelling cough as coft
• Good spelling in DASH tests cannot rule out poor spelling
 may be attributable to word selection
 Link standard spelling test with spelling in DASH tests
• Sound based errors are associated with phonological errors
 More often observed in poor readers
• Rule based errors are associated with word structure difficulties
 More often observed in good readers
Writing
• Fine motor problems will be seen in DASH
tests
 Note handwriting
 Link with scores from developmental coordination
disorder screening tools
 Link with performance on WRIT diamonds but
may be specific to handwriting
 Compare copy best and copy fast
 Free writing may deteriorate over time
(qualitative observations important here)
Writing
• Language difficulties will be
observed in free writing
 Compare scores with WRIT
verbal subscores
 May be consistently poor
rather than decline over
time
• Don’t forget to look at
spelling and word choice
Phonological awareness
• Subtests may not be equally sensitive:
 Elision subtest – involves repetition and allows for
other visual strategies
 Blending and phoneme isolation are purer
measures of PA
 Use of supplementary tests containing non-words
• eliminates the influence of vocabulary thus a purer test
• May be useful in adults
• Acceptable for APC as long as case made
Phonological awareness
• Scores may not be below average but…
 Qualitative analysis important as tests are not
timed
 Which of the items are difficult:
• Compound words: see[saw] - see
• Syllables: ri[der] - rye
• Onset and rime: ma[n] - ma
• Phonemes: tan[k]s - tangs
Phonological awareness
 Links can be made with TOWRE 2 (sight word
subtest may be better than phonemic decoding
subtest)
 Links can be made with spelling
• more on this later
 Links with reading single words
• Errors with phonetically plausible real words suggest
phonological awareness problem
Phonological memory
• Non-word repetition task (CTOPP 2)
 CTOPP 2 version does not include many established word
patterns
 task is purer
 Can be indicator of specific language impairment (Bishop
2006)
• Link with forwards letters and digits (correlated
strongly (Wijsman et al, 2000)
 These are established, familiar sounds
 If deficit here as well, then more generalised problem with
short term memory
Phonological memory
• What other clues might you be looking for?
 Teacher reports
 GORT comprehension subtest – low score may
mean less able to maintain information
 Specific to phonological information? Compare
with manual imitation (TOMAL2) – visual
information may be better held
Working memory
• TOMAL 2 is very useful as we can compare directly
backwards and forwards scores
 Manipulation of letters and numbers may be challenging
 Individuals with dyslexia make reversals of number pairs
and inversions (6 for 9)
• Make links with PA sub-tests: elision requires word
to be held and manipulated in WM
• Make links with memory for stories (TOMAL 2)
 Good for semantic memory
Speed of processing
• Typically measured by Rapid Automatic
Naming
• Not seen in all dyslexic individuals
• Possible subtype?
• Speed and quality of visual information is
compromised
• Letter identification is slowed
• Links between frequently occurring
letters are not made
Speed of processing
• May be related to orthographic skill rather than
phonemic encoding
• May mean slow access to phonological representations
rather than visual input (cancellation task) or
phonological output (articulation rate)
• Regular and irregular words are equally challenging
• Further reading: Wolf et al (2000) and Araujo et al (2010),
Georgiou et al, 2013
• Links can be made with:
 TOWRE: a good measure of reading fluency
 WIAT reading speed
 If generally slow processing - SDMT – speed of
processing
Language difficulties
• Background may reveal information:
 parental report describes word finding difficulties ‘she
knows the answer but she can’t find the word’
 Significant delay in acquisition of first words
• Verbal subtest of WRIT may reflect account
 requires a qualitative analysis – definitions may involve
pointing and using a basic explanation
• Analogies subtest of WRIT
 a feel for the answer but a difficulty expressing it
• Link with low score on phonological memory tests (Bishop
2006)
Language difficulties
• Be aware of discrepancy between performance and verbal
ability eg., average versus 70 (Georgopoulos et al, 2003)
 strict criteria but useful
• Comprehension is often better than production
• Qualitative information can be accessed through responses
on WIAT (an advantage over WRAT)
 Syntax is often impaired
 Mean length of utterance is short
Attentional difficulties
• Parent and teacher report is crucial here
 Inability to concentrate, finish anything, disrupts games
• Qualitative observations during testing also
important
• Use a screening tool to gather information
• A great website is http://www.sdqinfo.org/
• May not be clear indications on tests
 Cognitive Variability is hallmark of ADHD
 poor motivation, distractability during tests
Making links means comparing scores
• Where possible use confidence intervals of 95% but be
cautious with these
• If you have subtests which differ you can use confidence
intervals to be objective
• Convert scaled scores to standard or quotient scores
• Example: Comparison of digit forwards and manual imitation:
 Digit forwards 7 = 85 (SEM is 3) 95% CI is 79-91
 Manual imitation 10 = 100 (SEM is 3) 95% CI is 94-106
 No overlap thus confidence performance is markedly
discrepant
 Avoid use of the word ‘significant’ as you are not
performing a statistical test
Single subtests versus composites/
indexes
• It can be misleading to focus upon one subtest
 Especially if that subtest is not reliable (less than .9
reliability)
• APC preference is for composite scores where appropriate
• BUT if subtests within a composite are discrepant, it makes no
sense to ‘pool’ scores either
 Use outcomes cautiously
 Consider reliability of each test
 Use qualitative data
• If you don’t feel confident, just report composite scores CIs
Table of SEMS for CTOPP-2 and
TOMAL2
Using your own CIs
• You may wish to use your own calculations
but worry that they differ from those
provided in the table
• Use footnotes to make it clear
*Confidence intervals were calculated
using SEMs provided in manual
* Confidence intervals were calculated
using reliability coefficients provided in
the manual
Suggested statements
The scores for Test X and Test Y result in the lack of an overlap of the
associated confidence intervals of 95%. This discrepancy suggests that
the composite score associated with these tests has less meaning than
the individual test scores themselves.
There is a marked discrepancy between Test A and Test X as
defined by the lack of an overlap of the associated confidence
intervals of 95%. This suggests that Learner has difficulties with
skill A in comparison with skill X
It is best to avoid the word ‘significant’ as this implies
a formal test of score differences which has not been
carried out for these tests.
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