Reading and reading-related skills in
Williams and Down syndromes
Yonata Levy
Psychology Department
and Hebrew University-Hadassah Medical School, Jerusalem
This work was supported by a grant from
the Israel Science Foundation
Work on Hebrew was done in collaboration with my students:
Vered Antebi
Shani Beiser
Work with the American Williams syndrome group was done in
collaboration with Jason Smith and Helen Tager-Flusberg
We are grateful to the WS Associations in the US and in
Israel and to the Down syndrome Association in Israel, but
most of all
we are grateful to the children and their families
The research question:
Individuals with neurodevelopmental disorders that result in
cognitive disabilities are often reading impaired
But are they dyslexic??
The answer:
If reading disorders in these populations present themselves
along with the cluster of strengths and weaknesses that are
characteristic of dyslexic children then the answer is
If the profile is different then the answer is
NO
YES
What is dyslexia and what is it not
Until the mid 90’ies dyslexia was considered a condition
affecting typically developing children who, contrary to
expectations, failed to acquire reading at the expected
age, i.e. during the first years of elementary school
Crucially, dyslexic children scored average or above
average on IQ tests and were reading less well than
predicted by their IQ
Hence, there was a poorly understood
discrepancy
According to the discrepancy definition
Dyslexia is – (quoting)


. A disorder manifested by the difficulty in learning to
read, despite conventional instruction, adequate
intelligence and sociocultural opportunities. It is
dependent upon fundamental cognitive disabilities which
are frequently of constitutional nature
The condition we have when there is a clear discrepancy
between the person’s reading ability and other
intellectual abilities
Apart from ‘true dyslexics’, there are children who score
below average on intelligence tests who do not read well
The literature has referred to these children as
‘Garden variety poor readers’
In these children reading is one domain among many in which
they perform at the lower tail of their age level hence, they
are not dyslexic
‘Poor readers’ score low, but are still within one SD of the
normal range IQ (>85)
What was the theoretical appeal of the discrepancy
definition?
It highlighted the specificity of dyslexia, and being
‘specific’ was equivalent to being ‘theoretically
interesting’
Dyslexia has been thought about as a specific
reading disorder that is not related to the child’s
general cognitive functioning
The discrepancy definition crucially depends upon
1. An effect of IQ on reading in the ‘poor readers’
but not in dyslexics
2. That there be Differences between the profiles
characterizing dyslexic children and ‘garden
variety poor readers’
What is the characteristic profile of dyslexia?
When the clinical picture is considered, Dyslexia is a mixed bag,
but focusing on word reading the following profile emerges

Deficits in phonological awareness tasks
Deficits in short term auditory memory

Correlations with rapid object naming





Correlations with vocabulary size
Correlations with syntax and morphology
Children with a
history of SLI
Peripheral vision problems??
Problems in processing temporally sequenced information??
Note –
There has been relatively little research on reading in syndromic
populations yet, reading difficulties in these populations can
be easily accounted for within the discrepancy approach --
Mentally handicapped people have difficulties in
reading because of their mental handicaps
And this made research in this populations rather
uninteresting and had an effect on intervention as
well
However, research has provided little empirical
support for the discrepancy hypothesis
The profile that characterizes dyslexia is also
characteristic of ‘garden variety poor readers’
and IQ does not correlate with RD within this
group any more than it does in dyslexics
The research findings that forced a change in the definition of
dyslexia reflected a wide consensus among researchers
that the basic issues in RD relate to language and that
performance on intelligence tests was not a key issue
Since 1995, the definition of dyslexia considers it to be
“a specific language-based disorder of constitutional origin,
characterized by difficulties in single word decoding, usually
reflecting insufficient phonological abilities”
(Orton Society, 1995)
In the light of this definition, the research question
that the current study addresses is the following:
Are children with neuro-developmental
syndromes, specifically children with
Williams syndrome and children with Down
syndrome, who experience reading
difficulties, dyslexic?
Are they dyslexic – yes or no?
In order for the answer to be YES, the reading
difficulties seen in children with Williams
syndrome or with Down syndrome
should correlate with the familiar language
measures and not co-vary according to IQ
This work refers exclusively to decoding and
will only look at word reading
Williams syndrome - WS
Williams syndrome (WS)
→ A rare genetic disorder (1:20,000) which is typically not familial
→ The clinical phenotype includes 50-70 IQ on average, short stature,
unique facial features, high frequency of SVAS, hyper-acusis, hypercalcemia, orthopedic problems and a typical gait
→ A FISH test reveals a micro-deletion on 7q11.23 with around 24
genes missing, including the ELN gene
→ Individuals with WS are very friendly, talkative, with no fear of
strangers and with great love for music
→ WS cognitive profile is often described as unique – their expressive
language is fluent and grammatical, their vocabulary is rich, their
auditory short term memory is very good, their face processing is
good but their visual-motor and motor integration skills are way
below what is expected of their mental age
A recent MRI study by Galaburda and his team (2004) suggests
that participants with WS have reduced thalamic and occipital
lobe gray matter volumes and reduced gray matter density in
subcortical and cortical regions comprising the human visualspatial system, compared with controls
The WS group also showed disproportionate increases in volume
and gray matter density in several areas known to participate
in emotion and face processing, including the amygdala,
orbital and medial prefrontal cortices, anterior cingulate,
insular cortex, and superior temporal gyrus
Down syndrome - DS
Down syndrome (DS)
→ A common neurogenetic disorder, 1:600 with equal frequency
between males and females
→ DS occurs when there is duplication of chromosome 21
(trisomy 21) or part of it (mosaic)
→ The phenotype includes IQ 50-70 on average, unique facial
features, cardiac problems, frequent otitis media, early signs of
aging and high frequency of Alzheimer’s disease
→ The cognitive profile of individuals with DS is described as
depressed across tasks, with specific deficits in language skills
→ Individuals with DS have poor auditory short term memory
for words, poor vocabulary and even poorer syntax
Brain imaging studies of individuals with DS (Pinter et, 2001)
report of smaller overall brain volumes, with
disproportionately smaller cerebellar volumes and relatively
larger subcortical gray matter volumes
Also noted is relative preservation of parietal lobe gray and
temporal lobe white matter relative to control subjects. No
abnormalities in patterns of brain asymmetry have been noted
in Down's syndrome subjects
Recall what the characteristic dyslexia profile is like:

Deficits in phonological awareness tasks
Deficits in short term auditory memory

Correlations with rapid object naming





Correlations with vocabulary size
Correlations with syntax and morphology
Children with a
history of SLI
Peripheral vision problems??
Problems in processing temporally sequenced information??
If reading achievements and reading difficulties in these
populations draw upon similar language skills as does
reading in the normal population, we should expect –
1. Children with WS to acquire reading relatively easily
since their language skills are preserved and their
auditory short term memory for words is at age level
2. Children with DS to acquire reading with great
difficulty, if at all, since their language skills are poor
as is their auditory short term memory for verbal
material
3. IQ levels within the groups should not correlate with
word reading
We studied word reading and reading related skills
in :
1. English speaking adolescents and young adults in the
US, n=20 (Levy, Smith & Tager-Flusberg, 2003)
2. Hebrew speaking adolescents and young adults with
WS in Israel, n=17 (Levy & Antebi, 2004)
3. Hebrew speaking adolescents and young adults with
DS, in Israel, n=17 (Levy & Bieser, in preparation)
Participants were beyond the learning phase and were
considered by their educators as having reached the
highest reading level that they were capable of
Individuals who did not recognize the letters of the
alphabet were not included in the study
Individuals older than 22 years old were not included in the
studies in order to maintain some uniformity in the
educational practices
Since our interest was on word decoding - the focus of the
study was on reading novel words
Participants were tested on familiar word reading, rhyme,
phonological awareness tasks, rapid object naming,
vocabulary and syntax
We used normative tests whenever possible –
The K-BIT, CTOPP, Woodcock-Johnson and the PPVT for
English, and the Wechsler, Nizan and BNT for Hebrew
Experimental tasks were used for rhyme detection and for
syntax
Summary of findings in study 1
(Levy, Smith, Tager-Flusberg, 2003(
English speaking adolescents with WS
n=20; age=16.4 (12.8-20.4)




Three participants (15%) could not read even a single
novel word, i.e. they were “non-readers”
Non-readers failed the rhyming task, whereas the 17
readers were at ceiling on rhyme detection
Rapid naming was poor in the group as a whole
The best predictor of word decoding was performance on
the non verbal part of K-BIT
Correlations between word decoding (WordAtt), IQ
and reading-related skills in English speaking
readers with WS (n=17)
Correlations between word decoding (WordAtt), IQ
and reading-related skills in English speaking
readers with WS with K-BIT def. held constant
(n=17)
Reading and related skills in English speaking
adolescents with WS by IQ range (n=20)
30
IQ Range
40--49 (n = 8)
20
50--69 (n = 9)
69--84 (n = 3)
10
0
Ve
rb
M al
at
r
C i ce
om s
po
sit
e
PP
VT
L/
W
ID
At
ta
ck
R
O
N
El
W isio
or n
d
S
N eg
on
S
eg
Percentile Rank of
Mean Standard Score
40
Summary of findings in study 2:
(Levy and Antebi, 2004)
Hebrew speaking adolescents with WS
N=17; mean age 14;4 (11;3-22)

Non-readers were twice as many as in the English
speaking group – 6 individuals - ~35%

Performance on rhyming among the readers was at ceiling

Performance on rapid naming was poor across the board

The best predictor of word decoding was performance on
the Wechsler
Some relevant facts about Hebrew orthography
Hebrew marks most of its vowels as diacritics over and
below the line. For example:
yeled ‫יֶלֶ ד‬
migdal ‫ִמגְ ָדל‬
When diacritics are marked Hebrew has a shallow
orthography, i.e. there is a good mapping between
letters + diacritics and sounds
Hebrew orthography without diacritics is opaque
yld ‫ילד‬
mgdl ‫מגדל‬
Children are taught to read with diacritics
Word reading is mastered relatively early
However, diacritics are gradually dropped from written texts
from grade 3 and on and most adult written Hebrew is
without diacritics
Our task presented novel words with diacritics
It is possible that for individuals with WS who experience
specific difficulties in visual motor and visual integration
tasks, integrating two perceptually disparate systems
created a unique difficulty
Age, IQ and level of word reading in Hebrew speaking
participants with WS
Correlations between word reading, rapid naming,
vocabulary, phonological awareness and IQ in
Hebrew speaking readers with WS (n=11)
Word reading and language skills by IQ, in
Hebrew speaking adolescents with WS
2
IQ=41-49
1.5
IQ=50-69
IQ>70
1
0.5
-1.5
Ph
oD
lD
Sy
l
Ph
oS
W
or
dR
or
dR
T
Nw
-1
BN
RO
-0.5
N
0
Previous studies of reading in individuals with WS

Several studies have looked at reading in WS – Udwin et al
(1987), Howlin et al (1998), Laing et al (2001), Vicari et al
(2004)

Similar percentages of non-readers to our English sample were
reported

The studies did not focus on word decoding but looked at
comprehension as well

There has not been a systematic attempt to correlate word
reading with scores on IQ test

Since very young children – 6 yr. olds – were among the
participants studied such correlations would not be meaningful
Summary of study 3
(Levy & Bieser, in press)
Hebrew speaking adolescents with DS
N=17; mean age 17;06 (13;2 – 20;1)





Four participants ~ 27%, were non-readers, i.e. they could
not read a single novel word
Rhyme and rapid object naming did not correlate with word
reading
Syntax comprehension and production did not correlate with
word reading
Scores on the Wechsler as well as performance on
phonological awareness tasks correlated with word reading
Grammaticality judgments correlated with word reading
IQ and word reading in Hebrew speaking children with DS
Participant IQ
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
48
51
51
54
54
54
54
54
56
59
62
62
68
71
71
80
85
RWords
(N=59)
22
24
27
6
10
20
29
40
6
41
36
45
33
34
42
48
46
NWords
(N=24)
3
2
0
0
0
9
2
6
0
6
9
11
7
13
13
21
15
Correlations between word reading, rhyme,
phonological awareness tasks and IQ in Hebrew
speaking participants with Down syndrome
Correlation between word decoding, syntax
comprehension and production and grammaticality
judgments in Hebrew speaking adolescents with
Down syndrome
Word reading and reading-related skills by IQ, in
Hebrew speaking adolescents with DS
1.5



1.0





0.5



0.0







-0.5



-1.0


-1.5
RON
BNT

NonWords
PA1
BlockDesign
RealWords
Alliteration
Variables
high IQ (>70)
med IQ (52-69)
low IQ (<52)
Previous studies of reading in individuals with DS

Not many studied have looked at word reading in this
population

There have been reports of hyper-lexic children with Down
syndrome

A recent study (Laws & Gunn, 2002) reports of a higher
percent of non-readers than we found. However, age and IQ
have not been controlled for

Their follow-up study suggests that the higher the IQ, the more
likely the children are to acquire word decoding
Summary of the findings
Contrary to expectations, reading level in individuals with
WS was similar to reading level of IQ matched
individuals with DS
Rapid naming and vocabulary did not predict word
decoding in either group
Syntax did not predict word decoding in individuals with
DS
Phonological awareness and grammaticality judgments
were correlated with word decoding
Performance on IQ tests correlated with word decoding
Hebrew speaking individuals with
WS
DS
1.5
IQ=41-49
1.5
IQ=50-69
IQ>70
1
0.5
0



Mean (Z Score)
2
1.0
Nw
or
dR
W
or
dR
Ph
oS
Sy
llD
Ph
oD
BN
T
N
RO
-1



0.5



0.0






-0.5



-0.5



-1.0


-1.5
-1.5
RON
BNT

NonWords
PA1
BlockDesign
RealWords
Alliteration
Variables
high IQ (>7
med IQ (52
low IQ (<52
1 .5








2
high IQ (>70)
med IQ (52-69)
low IQ (<52)
IQ=41-49
1.5
IQ=50-69
IQ>70
1
0.5

-1.0


-1
Ph
oD
-0.5
lD


Sy
l
0
Ph
oS
-0.5

W
or
dR

or
dR

T

Nw



BN

0.5

N

0.0
RO
Mean (Z Score)

1.0
-1.5
-1.5
NonWords
PA1
BlockDesign
RealWords
Alliteration
Variables
40
30
IQ Range
40--49 (n = 8)
20
50--69 (n = 9)
69--84 (n = 3)
10
0
Ve
rb
M al
at
ri c
C
om es
po
sit
e
PP
VT
L/
W
ID
At
ta
ck
R
O
N
El
i
W sio
or n
d
S
N eg
on
S
eg
BNT
Percentile Rank of
Mean Standard Score
RON
The aim of this research was to find out whether
adolescents with either WS or DS who speak Hebrew or
English are, in fact, dyslexic
We asked whether the pattern of strengths and
weaknesses in word reading seen in the groups studied
was the same as the familiar dyslexia cluster
Based on our findings the answer is
NO!
We make the following claims:
Poor reading in WS and in DS does not arise from poor
language skills. The problem lies with the need to engage in
explicit learning of word decoding
Performance on IQ tests is a good predictor of a person’s
potential performance when explicit learning is called for
(phonological awareness tasks, grammaticality judgments)
The prediction is that in children with cognitive disabilities
other skills requiring explicit learning will show a similar
dependency on IQ
We offer to restore the intuition behind the discrepancy
definition of dyslexia since we think that reading
disorders in syndromic populations is
unlike dyslexia
The reading disorder seen in WS and in DS differ from
dyslexia in that they are not language related and they
concern difficulties with explicit learning of which reading
is but one domain
Such difficulties will be seen in people with intellectual
disabilities across syndromes and across knowledge areas
Understanding probability in WS
Step I:
Step II:
Experimenter throws
the dice
Which dreidel
would you like to spin?
The experiment was run with the Israeli group of
WS in two different versions:
a roulette version and a dreidel version
After making their choices and trying their luck,
children were asked to explain why they picked
one dreidel or the other
All the participants made the right choices well
above chance level
roulette: 72% (69-78; p<.001)
dreidel: 69.8% (66-75; p<.004)
Only four out of the 17 participants manage to
provide some explanation for their choices that
was vaguely related to probability
Conclusion
Learning of school type skills is primarily affected by a
person’s general cognitive abilities rather than by the
cognitive profile that is unique to a given syndrome
When explicit meta-cognitive learning is involved
general cognitive disability is the major impediment
To the extent that one can make the child
attend to the classroom material in an explicit
manner, learning is likely to be enhanced