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November 7, 2001
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2 - New Papers From The International Meeting for Autism
Research
The International Meeting for Autism Research (IMFAR) is
two-day scientific meeting comprised of all types of autism research - from molecular
biology to neuropsychology to treatment will be represented at their meeting in
San Diego, November 9 and 10.
The abstracts below are some of the scientific papers
being presented Friday afternoon by the researchers. Additional Friday afternoon and Saturday’s reports will be reproduced
here in subsequent postings of the FEAT Newsletter. All of the information is from the IMFAR website:
http://www.imfar.org/index2.html
Abstract Reasoning In Autism: A Dissociation Between
Rule-Learning & Concept Formation Abilities.
N. J. Minshew, G. Goldstein and J. Markus. Univ. of Pgh.
Sch. of Med., Pittsburgh, PA 15213.
Rule-learning and concept formation are separable
cognitive abilities within the abstract reasoning domain. It was hypothesized
that concept formation tasks, such as free sorting procedures, would
discriminate more accurately than attribute identification and rule-learning
tasks, such as the Wisconsin Card Sorting Test and the Halstead Category Test,
between 90 individuals with high functioning autism and 107 normal controls.
Performance was significantly different between
individuals with autism and a matched control group on all abstract reasoning
tasks. However, stepwise discriminant function analyses revealed that tests of
concept formation had greater discriminatory capacity than tests of concept identification.
This dissociation between rule-learning or concept identification and
higher-order conceptual integration within the domain of abstract reasoning
appears to be relatively unique to autism. The presence of this dissociation in
autism suggests there may be a distinct biological basis for these two
categories of abstraction abilities.
This dissociation provides an explanation for the rule
bound behavior typical of autism, difficulty with generalization and with novel
situations for which rules are not known. We conclude that the dissociation
between concept identification and concept formation more accurately
characterizes the range of abstract reasoning abilities found in higher ability
individuals with autism than executive dysfunction.
This study was supported by the National Institute of
Child Health and Human Development Grant HD35469 and National Institute of
Neurological Disorders Grant NS33355 to Nancy J. Minshew and by the Medical
Research Service, Department of Veterans Affairs.
* * *
Left Medial Frontal Cortex Joint Attention And Theory Of
Mind. P. Mundy. Center for Autism and
Related Disorders, University of Miami, Coral Gables, FL 33146.
Autism is characterized, in part, by a sequential
developmental disturbance in joint attention development and social cognition,
as measured on Theory of Mind measures. Recently, three studies have revealed a
left, medial-frontal contribution to the development of joint attention skills
in infancy (Caplan, 1993, Mundy et al. 2001, Yoder, in preparation).
Converging with these data, numerous studies have
implicated left medial and left inferior frontal contributions to theory of
mind performance in typical and atypical samples (e. g., Fletcher, et al. 1995;
Sabbaugh & Taylor, 1999; Russell et al. 2000).
These data suggest that a consideration of the functions
associated with a brain system involving the left medial cortex, and its
connections with the frontal eye fields, motor cortex, cingulated cortex,
thalamus and Broca’s area may make a heuristic contribution to emerging theory
on “social” brain circuits involved in autism.
This paper will: a) provide a review of data connecting
left medial process to joint attention and theory of mind, and b) present a
model of the potential contribution of the left medial cotical system to
understanding autistic pathology. The relations of this system to other CNS
areas likely involved in autism (e. g., cerebellar, temporal, orbital or
dorsolateral frontal cortex) will be discussed.
Supported by: NICHD R01 HD38052-01, SAMHSA KD1
SP09894-01; FLORIDA
STATE Dept. of Education, FDLRS Specialized Entrant
* * *
Evidence For Semantic Knowledge Across Three Input
Modalities In Low-Functioning Autism.
S. Higgins, K. I. Boser, & B. Gordon Div. of Cog.
Neuro., Dept. of Neurology, Johns Hopkins Med. Inst., Baltimore, MD 21287.
Attentional, motivational and sensory deficits in
low-functioning autism, as well as response bias and strategies, make
assessment of acquired knowledge especially challenging in this population. To
measure semantic knowledge more reliably, we developed a set of tasks assessing
comprehension of concrete nouns across 3 modalities (written, auditory and
iconic) in a low-functioning non-verbal autistic child (SR).
We examined consistency of responses and evaluated
performance on items previously trained in a picture to written word task on
the Foundations computer system. The subject was required to match a stimulus
to a corresponding color photograph, and the task included 300 items, presented
3 times, from 15 natural and 15 non-natural categories. Distracter items shared
both semantic and visual, only semantic, only visual, or neither feature with
the target. Results. SR demonstrated generalization of written training to
other input modalities.
Trained items were more likely to be correct across all
presentations and modalities. He generalized to untrained nouns, particularly
for trained semantic categories. SR performed better on natural than
non-natural categories across all modalities.
He made more errors to visual distracters in non-natural
categories for icon and written matching and more errors to semantic
distracters in natural categories for auditory and written matching. Therefore,
the current findings extend our previous results with AI, tested only in the
auditory modality, to SR, demonstrating evidence for broader semantic knowledge
when assessed across several input modalities.
Supported by: Dev. Cog. Neurosci. Gift & the Ben
Miller Endowment.
* * *
Discrimination Shift Learning And Task Complexity In Low-Functioning
Autism. K. I. Boser, S. Higgins, and B.
Gordon. Div. of Cog. Neuro., Dept. of Neurology, The Johns Hopkins Med. Inst.,
Baltimore, MD 21287.
Young children demonstrate initial use of exemplar-based
strategies in discrimination learning while older children are able to “abstract”
dimensional information. Extracting dimensional information leads to faster learning
of reversal shifts in which the rewarded feature shifts within a dimension from
training to test, but is impeded by memorization of exemplars.
However, memorization does not interfere in non-reversal
shift learning, since the rewarded feature shifts to a new dimension at test.
This task is an important measure of flexibility crucial for categorization and
concept learning. We examined 2 low-functioning, nonverbal children with autism
(SR & FN) and contrasted different methods for training discriminations:
1) two dimensions were
varied simultaneously within two different training sets;
2) one dimension was
varied across both sets; and
3) one dimension was
varied in only one set.
Results. SR learned reversal shifts faster than FN when
both stimulus dimensions were varied simultaneously, although many trials to
meet criterion (9/ 10 correct) were required. Varying the irrelevant dimension across
rather than within trials facilitated reversal shift learning for FN but not
SR. Both subjects had greater difficulty learning reversal than non-reversal
shifts when one set was presented in which only the relevant dimension varied.
These results have implications for teaching cognitive
skills to children with autism, particularly those requiring flexible
discrimination such as early concept and category learning.
Supported by: Dev. Cog.
Neurosci. Gift & the Ben Miller Endowment.
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* * *
“Item Mortality”: Factors And Possible Explanations. J. O’Grady, K. I. Boser, B. Gordon. Div. of
Cognitive Neurology, Dept. of Neurology, The Johns Hopkins Medical
Institutions, Baltimore, MD 21287.
“Item mortality” is the apparent “forgetting” of
previously learned items as new ones are taught. While normal subjects
demonstrate this, it is a particularly prominent and frustrating problem in
trying to teach low-functioning individuals with autism. There are a number of
possible explanations of item mortality, including, insufficient initial
learning, limited working memory, rapid forgetting, retroactive interference
and response competition.
However, what factor or combination of factors is
responsible for the effect in these individuals has not been determined. We
describe a series of educational and research studies of a single individual
that establish a reproducible methodology for demonstrating item mortality and
for investigating its causative factors. The basic tasks involved line drawings
to picture matching and auditory stimulus to picture matching and the task format
had been well practiced by the subject.
Item mortality was reproducibly demonstrated with
different items, across the two different input modalities. Item difficulty,
working memory demands (both for stimuli and for responses), and new learning
requirements are to be systematically varied in each modality, in ongoing
studies. Relevance of these data for
possible explanations for item mortality in this situation will be discussed.
Supported in part by the Developmental Cognitive
Neuroscience gift account, The Therapeutic Cognitive Neuroscience Endowment,
and The Benjamin A. Miller Endowment for Aging, Alzheimer’s Disease, and
Autism.
* * *
Impaired Learning Of Rotary Pursuit In Children With
Autism. S. H. Mostofsky, M. C. Goldberg
and M. B. Denckla. Kennedy Krieger Institute, Johns Hopkins School of Medicine,
Baltimore, MD 21205.
Deficits in procedural learning (acquisition of skills
through repeated practice or exposure to task) have been reported in children
with autism (Mostofsky et al., 2000), based on findings of impaired implicit sequence
learning on the Serial Reaction Time Test (SRTT).
The goal of this study was to determine whether children
(8-12 years) with high functioning autism (HFA) also show deficits in
acquisition of another motor skill, Rotary Pursuit. Seven children with HFA and
six gender-, age-, and IQ-matched controls performed four successive blocks of Rotary
Pursuit trials. Each block consisted of four trials, each lasting 20-seconds,
at a speed of 20 rpm. In blocks 1, 2, and 4 a circular pattern was presented;
in block 3 a square pattern was presented. There was a 20-minute break between
blocks 1 and 2. Learning was measured by the increase in mean time on-target
across the three circular blocks.
Results: Controls were significantly more on-target across
all blocks than were children with HFA (F = 20.7 (1, 11), p = .0008). A
repeated measure ANOVA revealed that controls showed a significantly greater improvement
in performance across the three circular blocks than did children with HFA (F =
19.4 (1, 11), p = .001).
In conclusion, these results suggest that children with
HFA have deficits in motor skill learning during Rotary Pursuit; although, a
factor of poor motor execution cannot be excluded. The findings provide further
evidence for a deficit in procedural learning in children with autism; however
future studies are needed to address whether the observed deficits are
secondary to impaired learning, execution, or both.
* * *
Examining The Relationship Between Executive Functions And
Restricted, Repetitive Symptoms Of Autistic Disorder.
B. R. Lopez, A. J. Lincoln, S. Ozonoff., Z. Lai.
Consulting Measurement Group, Inc., Institute for Developmental Research &
California School of Professional Psychology, University of Utah, Department of
Psychology, Scripts Research Institute.
Objective: To determine if a relationship exists between
executive functions (i. e., cognitive flexibility, planning, working memory,
fluency, and response inhibition) and the restricted, repetitive symptoms of
Autistic Disorder (AD).
Method: Seventeen adults with Autistic Disorder were
matched on age and Performance IQ to 17 healthy, nonautistic controls.
Executive functions were measured by the Delis-Kaplin Executive Function Scales
were administered to all the participants and autistic symptoms were measured
by the Autism Diagnostic Observation Schedule, the Autism Diagnostic Interview-Revised,
the Gilliam Autism Rating Scale, and the Aberrant Behavior Checklist-Community.
Results: The current study replicated the well-established
executive function profile of Autistic Disorder (i. e., deficits in cognitive flexibility
and planning, relatively unimpaired abilities in working memory and response
inhibition, and mixed findings in generativity). Cognitive flexibility, working
memory, and response inhibition were all found to be highly related to
restricted, repetitive symptoms, but planning and verbal fluency were not found
to be significantly correlated to restricted, repetitive symptoms. Obtained
data also suggest that cognitive flexibility plays a mediating role between
nonverbal fluency and restricted, repetitive symptoms. We found that multiple
executive functions are strongly associated with restricted, repetitive
behaviors.
Conclusion: A complex relationship exists between the
restricted, repetitive symptoms of AD and executive function component processes.
When accounting for restricted, repetitive symptoms of AD the entire executive profile
of AD needs to be considered. Moreover, findings from the present study suggest
a cognitive deficit model is insufficient to fully account for restricted,
repetitive symptoms of Autistic Disorder.
* * *
Time Processing Deficits In Autism .
Jill Boucher, Department of Psychology, University of
Warwick, Coventry, CV4 7AL, UK.
It is proposed that autism is caused by two fundamental
psychological deficits. One of these (a primary intersubjectivity or
socio-emotional processing deficit) is seen as the main cause of autistic socio-communicative
impairments, and is not the topic of this presentation.
The second primary deficit is hypothesized to affect
biopsychological time processing, and is seen as the main cause of the
repetitive behaviours and lack of creativity which partly define autism, and
also of the language impairments and mental retardation which commonly co-occur
with autism. In this presentation the time processing deficit theory will be
outlined, and the results of studies testing predictions arising from the
hypothesis will be reported.
The findings presented will be discussed in relation to
the theory itself, and in relation to other current psychological explanations
of autism, in particular, the weak central coherence theory and Minshew’s notion
of defective higher order integrative functions.
* * *
Adaptability In Children With Autism Spectrum Disorders. S. L. Hepburn, S. J. Rogers, W. L. Stone,
& G. Shub. University of Colorado Health Sciences Center, Denver, CO 80262.
“Adaptability” is a temperament characteristic that refers
to the ease with which an individual modifies behavior to adjust to changes in
social context. We hypothesized that low adaptability may be an early
manifestation of the insistence on sameness behaviors (e. g., restricted
interests, strict adherence to routines) which distinguish children with autism
from other developmentally disordered groups after the age of 3.
To evaluate this hypothesis, we conducted two studies. In
the first study, 28 two-year olds with autism were compared to 27 children with
developmental delays (groups comparable on mental and chronological age) on parent
report of adaptability. Two-year olds with autism were significantly less
adaptable than their peers, F( 1,55)= 4.72, p<. 05. Adaptability was significantly
correlated with severity of autism symptoms (r=. 37, p<. 01) and receptive
language ability (r=-. 27, p<. 05), but not to overall mental age.
In the second study, we compared 2-year olds with autism
to 42 four-to-five year olds with autism (mean age= 59 mos.) on adaptability. Younger children were significantly less
adaptable, F( 1,66)= 7.15, p<. 01. A
third inquiry into the relations between adaptability at age 2 and insistence
on sameness at age 4 is underway and suggests a strong association.
Implications for diagnosing very young children and
theoretical associations between adaptability and frontal lobe functioning will
be discussed.
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