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Dissociation of Cross-Sectional Trajectories for Verbal and Visuo-Spatial Working Memory Development in Rubinstein-Taybi Syndrome


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Working memory (WM) impairments might amplify behavioural difference in genetic syndromes. Murine models of Rubinstein-Taybi syndrome (RTS) evidence memory impairments but there is limited research on memory in RTS. Individuals with RTS and typically developing children completed WM tasks, with participants with RTS completing an IQ assessment and parents/carers completing the Vineland Adaptive Behavior Scales. A cross-sectional trajectory analysis was conducted. There were significant WM span deficits in RTS relative to mental age. Verbal WM span was positively associated with mental age; however, this was not observed for visuo-spatial span. There is a dissociation between WM domains in RTS. Individuals may have difficulties with tasks relying on WM span, above difficulties predicted by overall ability.
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Dissociation of Cross-Sectional Trajectories for Verbal
and Visuo-Spatial Working Memory Development in
Rubinstein-Taybi Syndrome
Jane Waite
Sarah R. Beck
Mary Heald
Laurie Powis
Chris Oliver
Published online: 24 March 2016
ÓThe Author(s) 2016
Abstract Working memory (WM) impairments might
amplify behavioural difference in genetic syndromes.
Murine models of Rubinstein–Taybi syndrome (RTS)
evidence memory impairments but there is limited research
on memory in RTS. Individuals with RTS and typically
developing children completed WM tasks, with partici-
pants with RTS completing an IQ assessment and par-
ents/carers completing the Vineland Adaptive Behavior
Scales. A cross-sectional trajectory analysis was con-
ducted. There were significant WM span deficits in RTS
relative to mental age. Verbal WM span was positively
associated with mental age; however, this was not observed
for visuo-spatial span. There is a dissociation between WM
domains in RTS. Individuals may have difficulties with
tasks relying on WM span, above difficulties predicted by
overall ability.
Keywords Working memory Short-term memory
Rubinstein–Taybi syndrome Typically developing
children Dissociation
A growing body of research identifies impairments of
executive functions (EFs) as relevant to explaining
behavioural difference in people with genetic disorders
(Woodcock et al. 2009). Studies of associations between
specific cognitive profiles and behaviour can elucidate
possible pathways from genetic disorder to behaviour via
atypical brain development and interactions with the
environment (Woodcock et al. 2011). One component of
EF that warrants further investigation is working memory
(WM) (Wang and Bellugi 1994).
WM is served by two slave information processing
systems: the visuo-spatial sketchpad processes visual and
spatial information and the phonological loop processes
verbal information (Baddeley and Hitch 1974). A distinc-
tion is often made between simple and complex WM tasks.
Garon et al. (2008) define simple WM tasks as tasks
requiring a person to hold information in mind in either of
these systems (synonymous with short-term memory;
STM), while complex WM tasks require information to be
to manipulated and updated in WM. Compromised simple
or complex WM impact on the ability to act purposefully,
learn effectively and accomplish goals (Baddeley 1986).
There is evidence that these core information processing
systems (phonological loop and visuo-spatial sketchpad)
can be differentially impaired; lending support for the
separation of these systems in the classic model of WM
(Wang and Bellugi 1994). For example, individuals with
localised brain injury have shown greater impairment to
one system (Hanley et al. 1991), and interference from
competing cognitive tasks can impact these systems dif-
ferentially (Logie et al. 1990). In addition, dissociations
have been evidenced in the visuo-spatial sketchpad
between the processing of visual and spatial information
(Vicari et al. 2004).
Wang and Bellugi (1994) argued that one approach to
studying these dissociations is to explore WM profiles in
rare genetic syndromes. WM has been studied in rare
&Jane Waite
School of Psychology, Cerebra Centre for
Neurodevelopmental Disorders, University of Birmingham,
Edgbaston, Birmingham B15 2TT, UK
Specialist Learning Disability and Forensic Services,
Hertfordshire Partnership NHS Foundation Trust,
Hemel Hempstead, UK
School of Psychology, University of Birmingham,
Birmingham, UK
J Autism Dev Disord (2016) 46:2064–2071
DOI 10.1007/s10803-016-2736-2
Content courtesy of Springer Nature, terms of use apply. Rights reserved.
genetic syndromes and dissociations are reported. Jarrold
et al. (1999) found that individuals with William syndrome
performed poorly on simple visuo-spatial WM tasks rela-
tive to mental age (MA). However, relative strengths were
evident for simple phonological WM tasks. The opposite
pattern was found for Down syndrome. Other syndromes
might further inform this potential dissociation. A rela-
tively neglected syndrome in which WM impairments are
implicated from murine models but not yet explored in
humans is Rubinstein–Taybi syndrome (RTS).
RTS is a multiple congenital anomaly syndrome esti-
mated to occur in 1:100,000 to 1:125,000 live births and
most often associated with chromosome 16p.13.3; however,
genetic diagnosis is only possible in around 55 % of indi-
viduals. The majority of diagnoses are based on the physical
phenotype that includes short stature, downward slanting
perebral fissures, short ‘‘beaked’’ nose and broad thumbs
and toes (Hennekam 2006). Behavioural characteristics
include insistence on sameness, adherence to routine and
repetitive questions (Waite et al. 2015), with tentative evi-
dence of heightened social interest in RTS in comparison to
individuals matched on developmental level (Gale
´ra et al.
2009). Intellectual disability (ID) ranges from mild to sev-
ere, with expressive language delayed (Clarke and Langton
1992). Few cognitive and behavioural differences have
been identified between those with and without a geneti-
cally confirmed diagnosis (Bartsch et al. 1999). Murine
models have led to the proposal that ID may be underpinned
or exacerbated by impaired learning due to long-term
memory (LTM) deficits (Oike et al. 1999; Weeber and
Sweatt 2002; Wood et al. 2005); however, no published
studies have systematically investigated memory.
While it has been hypothesised that impaired LTM
underlies compromises learning in RTS, LTM is a single
component of a broader memory system. Models of
memory highlight that LTM interacts with WM. The suc-
cessful interaction of WM and LTM processes contributes
to knowledge acquisition and problem solving (Logie
1996). Additionally, WM and set-shifting have been linked
to repetitive behaviours, and an inability to recall words on
a STM task has been linked to perseverative speech in
dementia (Woodcock et al. 2009; Turner 1999; Cullen et al.
2005). In RTS, elevated levels of repetitive questioning
have been noted (Waite et al. 2015). One possibility is that
WM deficits are associated with repetitive questions. In this
study we focus on WM as the first step toward developing a
model of compromised memory underpinning impaired
learning and behavioural characteristics in RTS.
Studying WM development in RTS requires an appro-
priate comparison group. In TD children, WM has been
associated with the development of various abilities
including: vocabulary acquisition, reading comprehension,
mathematics, decision making and theory of mind (Bull
et al. 2008; Engle et al. 1999; Cain et al. 2004; Carlson
et al. 2002; Baddeley 1986). Understanding the WM profile
of RTS relative to TD children may lead to more specific
hypothesises concerning the relationship between memory
and other cognitive abilities in this syndrome. This
approach also enables consideration of whether individuals
with RTS have WM impairments aligned with global MA
or whether they have a profile of strengths and weaknesses
relative to MA. The principal aim of this study was to
explore the cross-sectional developmental trajectories of
working memory domains in RTS in comparison to TD
Thirty-two participants with RTS were recruited (16 males;
mean chronological age: 221 months; chronological age
range 46–533 months; SD: 121.03). Of these, twenty-seven
were recruited from an existing database held by the
Cerebra Centre for Neurodevelopmental Disorders and five
via the RTS UK Support Group. Participants were included
if they were mobile and had a confirmed clinical diagnosis.
Eleven participants were excluded from analysis of the
WM tasks because they could not comprehend the task
instructions due to young age and/or severity of ID, or
because MA fell outside the range of the TD comparison
group. The mean chronological age of the remaining 21
participants was 232 months (9 males; age range
81–453 months; SD: 104.66). Of these participants, one
did not complete the Verbal Animal Span task due to poor
TD Children
The TD comparison group comprised eighty-nine children
(mean chronological age: 62 months; 40 males; range
38–89 months; SD: 15.10) tested in schools in the West
Midlands, UK. Participants were included if they were not
identified by their class teacher as having a developmental
disability. To ensure a spread of ages, where possible, eight
TD children were tested in each 6 month age band between
38 and 89 months. TD data for the Scrambled Boxes tasks
were not collected beyond 78 months as the task was not
deemed developmentally appropriate.
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As moderate to severe ID is characteristic of RTS, delayed
EF development relative to chronological age would be
expected. Therefore, assessments were administered to
explore whether EFs were delayed/deviant relative to glo-
bal cognitive development (MA). Individuals with RTS
completed assessments of cognitive ability to ascertain MA
and three WM tasks.
Measures of General Cognitive Functioning
Participants with RTS completed the Mullen Scales of
Early Learning (MSEL: Mullen 1995), suitable for indi-
viduals from birth to 68 months. Participants at ceiling on
the MSEL completed the Wechsler Abbreviated Scales of
Intelligence—Second Edition (WASI-II: Weschler 1999),
suitable for individuals from 72 months–89 years. Stan-
dardised scores could not be derived for many participants
because, due to degree of ID, individuals completed the
MSEL despite being older than 68 months. MA equivalent
scores were calculated for the MSEL by calculating the
average of subscale scores from the receptive and expres-
sive language, visual reception and fine motor domains
(Richler et al. 2010). The gross motor domain was omitted
as the highest obtainable MA on this scale was lower than
the other scales. Similarly, MA was calculated for the
Wechsler Abbreviated Scales of Intelligence (WASI-II), by
averaging the MAs across sub-domains.
Adaptive Behaviour Assessment
The Vineland Adaptive Behavior Scales—Second Edition
(VABS-II; Sparrow et al. 2005) was included as an alter-
native measure of MA. This is a parent report measure of
adaptive functioning. There are no guidelines for comput-
ing global MA for the VABS. In the same manner as for
the psychometric assessments, global MA was calculated
by taking an average across the nine primary domains.
WM Test Selection and Administration
Tasks were selected from the developmental literature and
adapted to reduce receptive language demands. Two simple
WM tasks, the Verbal Animal Span and Corsi Blocks, were
included because pilot work indicated that individuals with
RTS had difficulty comprehending the rules for complex
WM tasks. One complex WM task, the Scrambled Boxes,
was included as it is suitable for very young children
(Carlson 2005). The WM tasks were administered as part
of a battery of EF tests constructed for a wider research
project and were administered in a fixed order. Deviations
from this order occurred for six participants who had
difficultly engaging with the verbal task first (order: Corsi
Blocks, Scrambled Boxes, Verbal Span). No significant
differences were found on task scores between these par-
ticipants and participants who completed the verbal span
task first (ps [.05).
Corsi Blocks (Pickering et al. 1998)
Participants were presented with a 20 925 cm white
board with ten 3.4 93.4 cm blue blocks mounted irregu-
larly. On each trial the researcher touched a sequence of
blocks starting with sequences of two. Participants
responded by touching the same sequence of blocks. After
two practise trials of two block sequences feedback was
given. Every three experimental trials the number of blocks
in a sequence increased by one. The task was terminated
after three consecutive incorrect trials. An adapted version
of a one point per pair coding scheme was adopted (Fudala
et al. 1974). For example, if the sequence was block 3,
block 6, block 7, block 2 and the response given is block 3,
block 6, block 7, block 2 then the paired item score was 3
(i.e. 3–6, 6–7 and 7–2). If the response was block 3, block
6, block 3, block 7 the paired score would be 1. Only
participants able to point to at least one block correctly on
each practise trial and who attempted to locate two blocks
in the correct order (demonstrating rule understanding)
completed experimental trials.
Verbal Animal Span (Adapted from Digit Span, Bull et al.
This task followed the same protocol and coding as the
Corsi Blocks task except participants verbally repeated
strings of animal names (all one syllable) after the exper-
imenter said them. This task was adapted from the tradi-
tional digit span for individuals less familiar with numbers.
Scrambled Boxes Task (Adapted from Diamond 1990)
Three versions of this task were included: Three, Six and
Nine Scrambled Boxes. The test equipment was eighteen
round wooden boxes (diameter =7 cm) each decorated
with a different shape, nine foam stars, a cardboard treasure
chest, a 29.7 942 cm cardboard screen and two cardboard
baseboards that indicated where the boxes should be
positioned in each task. Boxes were positioned 5 cm apart
for the Three Scrambled Boxes and 8 cm apart for the Six
and Nine Scrambled Boxes task respectively. In all ver-
sions, participants watched the experimenter put a star in
each box and close them. Participants were asked to find
stars and put them in a treasure chest. Once a box was
selected and the star removed, the empty box was returned,
the boxes were hidden behind the screen and the positions
2066 J Autism Dev Disord (2016) 46:2064–2071
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of the boxes were scrambled by the researcher. The boxes
were scrambled for 5 and 10 seconds in the three and six/
nine Scrambled Box task respectively. Participants then
searched again.
The Six Scrambled Boxes task was administered first. If
a participant retrieved all six stars without error the task
was repeated using nine boxes and a full score was given
for the three box task. If an error was made the task was
repeated with three boxes and a score of zero given on the
nine box task. Maximum scores for the Three, Six and Nine
Scrambled Boxes tasks were four, seven and ten respec-
tively, with one point lost for each incorrect reach. The task
was terminated if the participant lost all their points. A
composite scaled score was calculated by summing scores
from the three tasks.
Data Analysis
Validity of MA Equivalent Scores and Association
with CA
Mean age equivalent score for the total RTS group
(N =32) on the direct cognitive assessments (MSEL and
WASI) was 61.83 months (SD: 34.20). Mean age equiva-
lent score on the indirect informant report measure (VABS-
II) was 65.89 months (SD: 37.16). A Wilcoxon test
revealed no significant differences between these scores.
The intraclass correlation coefficient between the direct
and indirect MA equivalent scores was calculated to
measure the level of agreement: .91 (95 % CI Lower =
.82, Upper =.96, (df: 30, 30), F =21.41, p\.001).
Given the high level of convergence between MA equiv-
alent estimates, only scores from the direct assessments
(MSEL and WASI) were used in further analyses.
To aid interpretation of MA cross-sectional trajectories a
linear regression was conducted to explore associations
between MA (MSEL and WASI) and CA in RTS. A
straight line fitted these data (R
=.41, F(1,30) =20.50,
p\.001) with an intercept of 4.18 and a gradient of 0.27;
95 % CI 2.31–5.83).
Analysis of WM Tasks
As development is a dynamic process, traditional group
comparisons that match a syndrome group to a control
group can obscure important changes in the cross-sectional
developmental trajectory of the syndrome group (Karmil-
off-Smith 1998; Thomas et al. 2009). For example, if there
is a peak in performance at a particular age followed by a
decline this may be obscured when a group average is
taken. Thomas et al. (2009), Thomas (2010) described how
linear cross-sectional trajectory analysis, involving the
graphical representation of all data points, can aid under-
standing cognitive development whilst overcoming the
limitations of matching. This methodology was applied to
data obtained from the simple WM tasks. Data from the
Scrambled Boxes task were not appropriate for linear
cross-sectional trajectory analysis so independent t-tests
were conducted, with an alpha level of .01 to correct for
multiple tests.
Prior to the between groups linear cross-sectional tra-
jectory analysis, regression lines were fitted to the simple
WM task data for each group. Between Groups linear
cross-sectional trajectory analysis compares the intercepts
(onset of the lines) and gradients (slopes of the lines) of
two cross-sectional trajectories that are plotted as a func-
tion of age to ascertain whether the trajectories differ for
the two groups at the earliest age of measurement (equiv-
alent of a main effect of group), and whether age may
differentially impact on the two groups. The analysis was
conducted as described by Thomas et al. (2009), Thomas
(2010) by making an adaption to the Analysis of Covari-
ance function within General Linear Model (ANCOVA).
Typically, including two groups with different cross-sec-
tional trajectories in an ANCOVA is a violation of the
test’s assumptions because ANCOVA computes one
regression function during the analysis; however, by add-
ing an interaction term to this model (group 9age) it is
possible to compare the slope of the two cross-sectional
trajectories. The x-axis was rescaled prior to the analysis so
that the intercept of the regression lines would represent
scores at the youngest age of measurement. Further details
on this method are available at:
The descriptive statistics for the WM tasks are displayed in
Table 1with linear cross-sectional trajectories for the
Verbal Animal Span and Corsi Blocks displayed in Fig. 1.
Verbal Animal Span Cross-Sectional Trajectory
Initial regression analyses indicated that a straight line
fitted the RTS data, R
=.31, F(1, 18) =8.04, p=.01,
with an intercept of 5.30 and gradient of 0.16, and the TD
data, R
=.24, F(1, 87) =27.85, p\.001, with an
intercept of 13.61 and gradient of 0.28.
The adapted ANCOVA indicated that a significant
proportion of the overall variance was explained by this
model, F(3,105) =26.59, p\.001, =.43. There was a
8.31 point score difference between the intercepts of the
TD and RTS and TD trajectories, F(1,105) =5.95,
p=.016, g
=.05. When the TD and RTS groups were
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combined, MA significantly predicted score on the Verbal
Animal Span, F(1,105) =11.17, p=.001, g
however, there was no significant age x group interaction,
F(1,105) =.94, p=.334, g
=.01. Thus, the significant
score difference between the groups remained consistent
across the age range.
Corsi Blocks Cross-Sectional Trajectory Analysis
Linear regression analyses revealed that a straight line fit-
ted the TD Corsi Blocks data (R
=.49, F(1, 87) =82.78,
p\.001), with an intercept of 2.81 and gradient of .43. A
straight line did not fit the RTS data [R
=.02, F(1,
19) =0.46, p=.505] but this was due to the flat cross-
sectional trajectory (see Fig. 1). The cross-sectional tra-
jectory had intercept of 3.38 and gradient of .05.
The adapted ANCOVA indicated that a significant
proportion of the overall variance was explained by this
model, F(3,106) =.17.79, p\.001, =.14. The RTS and
TD scores were not significantly different at the youngest
age of measurement (intercepts) on the cross-sectional
trajectory, F(1,106) =.05, p=.837, g
\.01. There was
significant group 9age interaction, F(1,106) =13.23,
p\.001, g
=0.11. The RTS cross-sectional trajectory
appears flat, while the TD cross-sectional trajectory has a
positive slope with age (see Fig. 1).
The point at which the 95 % confidence intervals no
longer overlap (see Fig. 1) indicates that the cross-section
trajectories are reliably different at 49 months.
Scrambled Boxes Analysis
There were no significant differences between the RTS and
TD groups on the Three Scrambled Boxes, t(22.65) =
1.54, p=.137, d=0.22, Six Scrambled Boxes,
t(25.02) =1.78, p=.087, d=0.50, or Nine Scrambled
Boxes, t(38.20) =1.78, p=.140, d=0.33. Using our
adjusted alpha level the total score also failed to reach
significance, t(107) =2.31, p=.039, d=0.50. In addi-
tion, no significant correlations between performance and
MA were found.
This study explored the development of WM in RTS rel-
ative to MA using cross-sectional trajectory methods
Thomas et al. (2009), Thomas (2010). MA was calculated
by averaging MA equivalent domain scores from the
MSEL and, while this method is likely to only provide a
gross estimate of MA, the MAs appeared to have conver-
gent validity with MA estimates from an informant
assessment (VABS). Cross-sectional trajectories were then
presented for verbal and spatial span tasks. The results
indicated that WM span may be compromised in RTS but
performance was variable across tasks depending on the
aspect of WM measured.
Findings suggest that in RTS verbal and visuo-spatial
WM span may be compromised relative to MA. This is
illustrated by the Animal Span task and the Corsi Blocks
cross-sectional trajectories as performance on these tasks is
below that of the TD group. Despite this, there are some
differences between cross-sectional trajectories. On the
verbal span task, TD children consistently outperform the
Table 1 Descriptive statistics (mean, SD & range) on working
memory tasks for RTS and TD group
RTS (N =21) TD (N =89)
Mean (SD) Range Mean (SD) Range
Verbal animal span 8.75 (3.67) 0–17 20.36 (8.56) 6–51
Corsi blocks task 4.05 (2.78) 0–10 12.98 (9.09) 0–37
Scrambled boxes
8.14 (5.72) 4–21 10.95 (5.50) 2–21
R² = 0.2425
R² = 0.3085
35 45 55 65 75 85 95
Score on Verbal Animal Span
Age (TD = CA; RTS = MA)
R² = 0.4876
R² = 0.0237
35 45 55 65 75 85 95
Score on the Corsi Block Task
Age (TD: CA; RTS: MA)
Fig. 1 RTS and TD trajectories for scores on the span tasks as a
function of MA
2068 J Autism Dev Disord (2016) 46:2064–2071
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individuals with RTS. While the RTS group lags behind the
TD group, individuals with RTS who had higher MAs
performed better than those with lower MAs. The design is
cross sectional so change over time cannot be assumed;
however, a moderate association between MA and
chronological age suggests improvement in verbal span
with chronological age in RTS. The Corsi block span
shows a different pattern whereby there is initial overlap of
the RTS and TD cross-sectional trajectories at the youngest
age of measurement (MA) but the RTS trajectory remains
flat in contrast to the positive slope for the TD group. In
addition, a proportion of individuals with RTS were not
able to score on the experimental trials of this task (re-
quiring them to retain two items in memory) despite
understanding the rules of the task and memorising at least
one block during the practise phase.
Not all of the results suggest WM impairments in RTS
because the groups did not differ on the Scrambled Boxes
task, a visuo-spatial WM task. During this task participants
are required to remember distinct objects that vary on two
memorable dimensions (colour and shape) and this may be
less demanding than the Corsi block task that requires the
tracking of movement. There is evidence that tracking
movement has different neurological correlates than
remembering shape and colour, so these results may rep-
resent a dissociation of the visuo-spatial sketchpad (Vicari
et al. 2003; Logie 1996). Alternative interpretations are that
interacting with the boxes for a longer time or the imme-
diate reward from receiving stars may form stronger
memory representations (Vogel et al. 2006), or that the
recognisable shapes on the boxes led to some verbal
encoding and aided performance. Finally, a conservative
alpha level was used in the scrambled boxes analysis to
correct for multiple tests, so it remains possible that group
differences could exist on this task. As with all these tasks,
further investigation is necessary to extrapolate to the
mechanisms underlying performance.
As noted previously, it has been proposed that ID
associated with RTS may be linked to mutations in the
CREB binding protein and the effects on LTM associated
with hippocampal functioning (Oike et al. 1999; Weeber
and Sweatt 2002; Wood et al. 2005). A number of studies
with knock-out mice have explored the link between these
mutations and phenotypic characteristics, and while these
mice develop LTM difficulties, STM is not affected (see
Josselyn (2005) for a review). It has been be argued that
simple WM tasks, such as those included in the current
study, can only be defined as STM tasks because of the
absence of an updating component (Gathercole and Allo-
way 2006). Therefore, the poor performance of the RTS
group on simple WM tasks does not fit neatly with murine
models of RTS. Instead, these results point to a possible
double deficit of memory function.
A syndrome comparison group was not included in this
study but the RTS memory profile is likely to be pheno-
typic because WM lags behind overall ability. The memory
profile in RTS appears different to other syndrome groups.
For example, in Down Syndrome visuo-spatial skills are a
relative strength, whereas in William syndrome they are a
weakness relative to verbal skills (Jarrold et al. 1999).
Individuals with RTS evidence difficulties in both domains.
The results of this study will inform clinicians and
teachers working with RTS. External memory aids may be
particularly useful for helping individuals remember
information sequences and it may be helpful to present
information in no more than two–three chunks at a time.
The results suggest that older individuals with RTS are
likely to have more developed verbal WM spans and fur-
ther studies could explore the possibility of accelerating
development of verbal WM capacity using computerised
tasks that train this ability, as has been demonstrated pre-
viously (e.g. Klingberg et al. 2005). Finally, it would be
interesting to consider WM deficits in RTS in relation to
other aspects of the behavioural phenotype such as the high
levels of repetitive questioning noted in this group (Waite
et al. 2015).
As this is the first study of memory in individuals with
RTS, there are inevitably some limitations. Firstly, despite
the convergence of MA across assessments, MA can only
be taken as an estimate for examining gross dissociations in
cross-sectional trajectories at group level. In addition, it is
only possible to draw conclusions within the develop-
mental window between 38 and 89 months. Performance
of individuals with MAs outside this window may not map
onto these cross-sectional trajectories. In addition, partici-
pants with RTS would need to be followed up to confirm
whether higher performance on verbal span tasks in those
with higher MA represents developmental change. Finally,
the MSEL and VABS were not completed by the TD
comparison group due to constraints of testing in schools.
However, the sample of children was large, increasing the
likelihood of a MA cross-sectional trajectory accurately
reflecting the ability of the TD group.
Order effects may have occurred from fixed order
administration. It could be argued that poor performance on
the Corsi span task represents general fatigue and disen-
gagement. There was no statistical difference, however,
between the small subset of individuals who received the
Corsi block span first. Furthermore, all 21 participants went
on to complete a broader EF battery as part of a wide scale
study without demonstrating a drop off in performance that
characterised the Corsi block span; therefore, these results
appear robust. A further limitation of the Corsi block span
is that it may not discriminate well between the two groups
at the youngest ages since all children were at or near the
floor of the task. Overall, these results are an encouraging
J Autism Dev Disord (2016) 46:2064–2071 2069
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first step towards profiling memory in a syndrome in which
memory impairments would be anticipated given murine
models (Oike et al. 1999; Wood et al. 2005). In addition,
these results lend further support to a dissociation of the
phonological loop and visuo-spatial sketchpad. A differ-
ence in performance also was found between groups on the
Corsi Blocks task but not the Scrambled Boxes task. Whilst
these differences may be due to the nature of the tasks
used, this provides tentative evidence of a dissociation
between spatial processing (e.g. tracking movement) and
visual processing in the (e.g. colours and shapes) in the
visual spatial sketchpad and concurs with previous research
(Logie 1996, Vicari et al. 2003). Exploring the neurological
correlates of performance on these WM tasks in individuals
with RTS could provide further evidence for the dissocia-
tion of these abilities (Vicari et al. 2003).
Acknowledgments We are grateful to our funding body, Cerebra,
and the Rubinstein–Taybi Syndrome Support Group. We are grateful
to Hayley Crawford, Amsa Iqbal and Ruchi Bakshi for assistance with
data collection and coding.
Author Contributions JW, SRB, MH, LP and CO conceived the
study, participated in its design and coordination, analysis and
interpretation of data, drafted the manuscript, and revised it for
important intellectual content. All authors read and approved the final
Compliance with Ethical Standards
Conflict of interest The authors have no financial or other interests
related to the research in this manuscript.
Ethical Approval This study was approved by the NHS Coventry
and Warwickshire Research Ethics Committee.
Open Access This article is distributed under the terms of the
Creative Commons Attribution 4.0 International License (http://crea, which permits unrestricted use,
distribution, and reproduction in any medium, provided you give
appropriate credit to the original author(s) and the source, provide a
link to the Creative Commons license, and indicate if changes were
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... Difficulties in working memory have been described by Waite et al. (2016) [118]. This study compared 32 children with RTS to "mentally matched," typically developing children. ...
... Difficulties in working memory have been described by Waite et al. (2016) [118]. This study compared 32 children with RTS to "mentally matched," typically developing children. ...
Full-text available
The type 2 lysine methyltransferases KMT2C and KMT2D are large, enzymatically active scaffold proteins that form the core of nuclear regulatory structures known as KMT2C/D COMPASS complexes (complex of proteins associating with Set1). These evolutionarily conserved proteins regulate DNA promoter and enhancer elements, modulating the activity of diverse cell types critical for embryonic morphogenesis, central nervous system development, and post-natal survival. KMT2C/D COMPASS complexes and their binding partners enhance active gene expression of specific loci via the targeted modification of histone-3 tail residues, in general promoting active euchromatic conformations. Over the last 20 years, mutations in five key COMPASS complex genes have been linked to three human congenital syndromes: Kabuki syndrome (type 1 [KMT2D] and 2 [KDM6A]), Rubinstein-Taybi syndrome (type 1 [CBP] and 2 [EP300]), and Kleefstra syndrome type 2 (KMT2C). Here, we review the composition and biochemical function of the KMT2 complexes. The specific cellular and embryonic roles of the KMT2C/D COMPASS complex are highlight with a focus on clinically relevant mechanisms sensitive to haploinsufficiency. The phenotypic similarities and differences between the members of this new family of disorders are outlined and emerging therapeutic strategies are detailed.
... Finally, only one developmental study focusing on cognitive ability showed evidence of the dissociation between the developmental trajectory of two areas of the working memory of children with RSTS (Waite, Beck, Heald, Powis, & Oliver, 2016), emphasising that the visual-spatial memory was impaired in terms of mental age, as opposed to verbal memory. ...
Background: Rubinstein-Taybi syndrome (RSTS) is a multiple congenital anomaly syndrome characterised by several typical somatic characteristics and by developmental disabilities with various degrees of severity. Focusing on children with RSTS, the aim of this study was to describe their psychomotor, cognitive, and socio-emotional developmental profiles. Method: Twenty-three children with RSTS (12 boys; 11 girls; mean chronological age: 4 years and 10 months) with severe intellectual disability (mean developmental quotient = 32.39) were recruited from an Expert Department of Medical Genetics. Developmental assessments were carried out with the Brunet-Lézine-Revised scale and the Social Cognitive Evaluation Battery. Results: The participants’ developmental profiles were characterised by heterogeneous psychomotor development, homogeneous cognitive and socio-emotional development, by more severe delays in expressive language, vocal imitation, and symbolic play skills, and by better developmental levels in socio-emotional abilities. Conclusions: Based on these atypical developmental profiles, early interventions should target the three most delayed abilities.
... Adaptive abilities in the SMS group were assessed using the Vineland Adaptive Behavior-2 Interview (VABS [19]; Sparrow, 2011) to include receptive, expressive and written communication, personal, domestic, community, interpersonal relationships, play and leisure, coping skills and gross and fine motor skills. An overall developmental age score was derived by averaging these 11 scores, adapting the method used previously [20]. No measure of ability was used in the TD group; chronological age was assumed to be commensurate with developmental age as no statements of additional learning needs were indicated. ...
Study Objectives 1) To compare both actigraphy and questionnaire assessed sleep quality and timing in children with Smith-Magenis syndrome (SMS) to a chronologically age-matched typically developing (TD) group. 2) To explore associations between age, nocturnal and diurnal sleep quality and daytime behaviour. Methods Seven nights of actigraphy data were collected from 20 children with SMS (mean age 8.70; SD 2.70) and 20 TD children. Daily parent/teacher ratings of behaviour and sleepiness were obtained. Mixed linear modelling was used to explore associations between total sleep time and daytime naps and behaviour. Results Sleep in children with SMS was characterised by shorter total sleep time (TST), extended night waking, shorter sleep onset, more daytime naps and earlier morning waking compared to the TD group. Considerable inter-daily and inter-individual variability in sleep quality was found in the SMS group, so caution in generalising results is required. An expected inverse association between age and TST was found in the TD group, but no significant association was found for the SMS group. No between group differences in sleep hygiene practices were identified. A bidirectional negative association between TST and nap duration was found for the SMS group. In the SMS group increased afternoon sleepiness was associated with increased irritability (p=.007) and overactivity (p=.005). Conclusion These findings evidence poor sleep quality in SMS and the need to implement evidence-based interventions in this population.
Rubinstein–Taybi syndrome (RTS) is a rare genetic syndrome associated with growth delay, phenotypic facial characteristics, microcephaly, developmental delay, broad thumbs, and big toes. Most research on RTS has focused on the genotype and physical phenotype; however, several studies have described behavioral, cognitive, social, and emotional characteristics, elucidating the behavioral phenotype of RTS. The reporting of this review was informed by PRISMA guidelines. A systematic search of CINAHL, Medline, and PsychINFO was carried out in March 2021 to identify group studies describing behavioral, cognitive, emotional, psychiatric, and social characteristics in RTS. The studies were quality appraised. Characteristics reported include repetitive behavior, behaviors that challenge, intellectual disability, mental health difficulties, autism characteristics, and heightened sociability. Findings were largely consistent across studies, indicating that many characteristics are likely to form part of the behavioral phenotype of RTS. However, methodological limitations, such as a lack of appropriate comparison groups and inconsistency in measurement weaken these conclusions. There is a need for multi-disciplinary studies, combining genetic and psychological measurement expertise within single research studies. Recommendations are made for future research studies in RTS.
Background Cognitive and socio-emotional profiles of children with CREBBP-related Rubinstein-Taybi syndrome (RSTS 1), children with Autism Spectrum Disorder (ASD) with severe intellectual disability and developmental ages (DA) under 24 months, and typically developing (TD) children with similar DA were compared. Participants Thirty-one children with RSTS 1 (mean chronological age, CA = 59,8 months; 33−87) and thirty children with ASD, matched on CA and DA and developmental quotients (DQ), were compared to thirty TD children (CA ranged from 12 to 24 months). Methods Cognitive and socio-emotional developmental levels, DA and DQ were assessed with appropriated tests. Results More socio-emotional developmental similarities were observed between TD and RSTS 1 than between TD and ASD children. Clinical groups displayed similar developmental delays in cognitive (self-image, symbolic play, means-ends, and object permanence) and socio-emotional domains (language and imitation). Children with RSTS 1 exhibited higher developmental levels in behavior regulation, joint attention, affective relations, emotional expression domains, and a lower developmental level in spatial relations domain. Conclusions Common interventions centered on symbolic play, self-image, language, and imitation for both clinical groups, and differentiated interventions centered on spatial abilities for RSTS 1 children and on social abilities for ASD could be used by caregivers were suggested.
Rubinstein‐Taybi syndrome (RSTS, OMIM*180849) is a rare autosomal dominant disorder, characterized by distinctive facial features, short stature, broad and often angulated thumbs and halluces, with occasional congenital anomalies. Characteristic facial dysmorphic features include downslanting palpebral fissures, low hanging columella. RSTS is caused by pathogenic variants in two ubiquitously expressed and highly homologous genes, CREBBP (OMIM*600140) and EP300 (OMIM*600140). Clinical features were well reported especially in Caucasian ethnicity. We would like to report the clinical phenotype of RSTS in our Chinese population and highlight four novel mutations in CREBBP gene.
Full-text available
We directly assessed the broader aspects of sociability (social enjoyment, social motivation, social interaction skills and social discomfort) in individuals with Cornelia de Lange (CdLS), fragile X (FXS) and Rubinstein-Taybi syndromes (RTS), and their association with autism characteristics and chronological age in these groups. Individuals with FXS (p < 0.01) and RTS (p < 0.01) showed poorer quality of eye contact compared to individuals with CdLS. Individuals with FXS showed less person and more object attention than individuals with CdLS (p < 0.01). Associations between sociability and autism characteristics and chronological age differed between groups, which may indicate divergence in the development and aetiology of different components of sociability across these groups. Findings indicate that individuals with CdLS, FXS and RTS show unique profiles of sociability.
Full-text available
Syndrome specific repetitive behavior profiles have been described previously. A detailed profile is absent for Rubinstein-Taybi syndrome (RTS). The Repetitive Behaviour Questionnaire and Social Communication Questionnaire were completed for children and adults with RTS (N = 87), Fragile-X (N = 196) and Down (N = 132) syndromes, and individuals reaching cut-off for autism spectrum disorder (N = 228). Total and matched group analyses were conducted. A phenotypic profile of repetitive behavior was found in RTS. The majority of behaviors in RTS were not associated with social-communication deficits or degree of disability. Repetitive behavior should be studied at a fine-grained level. A dissociation of the triad of impairments might be evident in RTS.
Full-text available
The purpose of this book is to compare and contrast different conceptions of working memory. This is one of the most important notions to have informed cognitive psychology over the last twenty years, and it has been used in a wide variety of ways. This, in part, is because contemporary usage of the phrase "working memory" encapsulates various themes that have appeared at different points in the history of research into human memory and cognition. The book presents three dominant views of working memory.
This chapter is divided into two parts. The first describes the effect of Pat Rabbitt's influence in encouraging the first author to use the increasingly sophisticated methods of ageing research to answer questions about the fundamental characteristics of working memory, together with reflections on why so little of this work reached publication. The second part presents a brief review of the literature on working memory and ageing, followed by an account of more recent work attempting to apply the traditional method of experimental dissociation to research on normal ageing and Alzheimer's disease. The discussion suggests that even such simple methods can throw light on both the processes of ageing and the understanding of working memory.
This chapter describes each of the seven "ages" or instantiations of working memory, which include the views of working memory as contemplation, as process, and as constraint of language comprehension. It evaluates which view fits best with the voluminous corpus of empirical data that has accumulated on the topic and argues that working memory is best thought of as a number of separate components. The chapter also discusses the idea that working memory acts as a gateway to long-term memory.
A study was conducted in which 133 participants performed 11 memory tasks (some thought to reflect working memory and some thought to reflect short-term memory), 2 tests of general fluid intelligence, and the Verbal and Quantitative Scholastic Aptitude Tests. Structural equation modeling suggested that short-term and working memories reflect separate but highly related constructs and that many of the tasks used in the literature as working memory tasks reflect a common construct. Working memory shows a strong connection to fluid intelligence, but short-term memory does not. A theory of working memory capacity and general fluid intelligence is proposed: The authors argue that working memory capacity and fluid intelligence reflect the ability to keep a representation active, particularly in the face of interference and distraction. The authors also discuss the relationship of this capability to controlled attention, and the functions of the prefrontal cortex.
Conference Paper
Background: Over the past several years, numerous studies have reported improvements in restricted and repetitive behaviors (RRBs) as individuals with autism spectrum disorders (ASD) enter adulthood. These studies have yielded important findings, but are limited by aspects of their design, including reliance on retrospective parent report and use of cross-sectional data to make inferences about how behaviors change over time. Objectives: The primary aim of the present study is to learn more about the development of RRBs in ASD from childhood to adulthood. The study uses a longitudinal sample of children diagnosed with ASD at a very young age and repeatedly assessed throughout childhood and into early adulthood. The fact that the same individuals underwent repeated assessments using the same measures, and that parents were asked to report about their children’s current behaviors, allows us to make stronger conclusions about how RRBs change over time in ASD. Methods: Data were collected as part of a longitudinal study of toddlers referred for possible autism. Children were seen at approximately 2, 3, 5, 9, and 18 years of age. At each wave, children completed a battery of cognitive and diagnostic measures. Parents completed several questionnaires and interviews. RRB data for this study were obtained from the Autism Diagnostic Interview-Revised. At all waves (except the age 3 assessment), each child was assigned a consensus best-estimate clinical diagnosis of ASD (autism or pervasive developmental disorder-not otherwise specified) or a non-spectrum developmental disorder. Of the 161 children diagnosed with ASD at age 2, data are currently available for 78 participants. Data for approximately 20 additional participants will be available shortly. Results: Most behaviors were present in a substantial proportion of the young adults. Prevalence rates ranged from 22% for unusual preoccupations to 54% for unusual sensory interests and hand/finger mannerisms. Consistent with previous studies, there was also abatement of all RRBs over time; substantial proportions of those who had reportedly exhibited a behavior at one or more of the previous waves no longer exhibited that behavior at age 18. Rates of abatement ranged from 31% for circumscribed interests to 89% for resistance to trivial changes in the environment. For nearly all behaviors, those who showed abatement at age 18 had higher non-verbal IQ scores at age 2 than children who did not show abatement, but the only statistically significant result was for unusual sensory interests, t(70) = -2.4, p < .05. Conclusions: These initial findings provide further evidence for improvement in RRBs as individuals with ASD enter adulthood. Abatement may be associated with higher early NVIQ scores; this relationship requires further examination. Further analyses will examine RRBs subtypes (e.g., ‘repetitive sensorimotor’ versus ‘insistence on sameness’). We will determine whether trajectories of RRB development vary depending on the RRB subtype, and whether individual variables (e.g., IQ) predict patterns of change in RRB subtypes over time. Findings from the present study will have implications for the identification of subtypes of ASD based on RRB trajectories, and for our understanding of the prognosis of RRBs for different subgroups.
Conference Paper
Background: Little is known about the stability of individual restricted and repetitive behaviors (RRBs) in children with autism spectrum disorders (ASD) (i.e., how commonly behaviors are lost or improve and how often they are acquired or worsen over time.) There is evidence that ‘repetitive sensorimotor’ (RSM) behaviors (e.g., motor mannerisms) follow different developmental trajectories than ‘insistence on sameness’ (IS) behaviors (e.g., rituals). Objectives: We examine the stability of individual RRBs over time in children with ASD, and which factors are associated with stability. Methods: Data were collected as part of a longitudinal study of toddlers referred for possible autism. There were 214 participants in the first cohort, 192 of whom were referred because of concerns about ASD. The nonspectrum developmental disorder (DD) referral group consisted of 22 developmentally delayed children who had never been referred for or diagnosed with autism. At each wave, children completed a battery of cognitive and diagnostic measures, and parents completed the Autism Diagnostic Interview-Revised. At ages 2, 5, and 9, each child was assigned a consensus best-estimate clinical diagnosis of autism, pervasive developmental disorder-not otherwise specified, or a nonspectrum developmental disorder. Results: Once children with ASD had a particular RSM behavior, they were likely to continue having it, and children who did not have the behavior often acquired it. However, these behaviors often improved in children with higher nonverbal IQ (NVIQ) scores and/or milder ASD. Many children who did not have IS behaviors at a young age acquired them as they got older, whereas children who had these behaviors sometimes lost them. Trajectories of IS behaviors were not closely related to diagnosis and NVIQ. Conclusions: Individual RRBs show different patterns of stability in children with ASD, based partly on the ‘subtype’ they belong to. Young children with low NVIQ scores often have persistent RSM behaviors.