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J. Indian Assoc. Child Adolesc. Ment. Health 2016; 12(2):162-199
Review Article
The Neuropsychology of Autism – A Focus on Three Major Theories
Vanitha S Rao, Ashok V Mysore, Vijaya Raman
Address for correspondence: Dr. Vijaya Raman, Additional Professor of Clinical
Psychology, Department of Psychiatry, St. John’s Medical College Hospital,
Bengaluru. Email: [email protected]
ABSTRACT
Autism is a developmental disorder that is biological in origin with a behavioural definition.
Numerous neuropsychological theories have been suggested to explain the triad of
impairments in autism. In this paper we have discussed the neuropsychology of autism with
emphasis on the three frequently researched cognitive theories related to the impairments in
Theory of Mind, Executive Function skills and Central Coherence. Each of the theories
explains some aspects of the disorder but it is in combination that their explanatory power
seems to increase. Focus of future research needs to be on the interactions between these
neuropsychological deficits.
Key words: autism, theory of mind, executive dysfunction, weak central coherence,
neuropsychology
Introduction
Autism is a developmental disorder that is characterized by socio-communication deficits and
restricted and repetitive repertoire of behaviours [1]. Its prevalence in India is not adequately
ascertained; some western reports suggest that it affects 1 in 68 individuals [2].
163
Interest in understanding cognitive functions of individuals with autism has existed since
Kanner [3] reported them to be aloof, with poor communication skills but of normal
intelligence. Charman et al [4] have highlighted the challenges in establishing a cognitive
profile for autism. They consider the heterogeneous nature of the disorder and the difficulty
in obtaining large sample sizes for research as major impediments in this regard. A sound
neuropsychological theory clearly establishes the brain-behaviour connection. While many
theories have been proposed, there has been a dominance of research interest in three main
cognitive theories, Theory of Mind (ToM) [5], Executive Function (EF) [6] and Central
Coherence (CC) [7]. Although research often presents these three theories as separate
concepts they could be linked in ways that need investigation.
A seminal review paper [8] attempted to tease out the brain-behaviour-genetics connection in
autism. This paper proposed six broad autism phenotypic traits which is an admixture of
behavioural and cognitive characteristics. These traits are: a) face processing (b) social
affiliation (c) motor imitation (d) declarative memory/feature binding (e) executive function
and (f) language ability. Face processing and social affiliation are components underlying the
theory of mind. Motor imitation has been linked to language acquisition and social skill
development [9]. The declarative memory/feature binding trait has been linked to central
coherence and mapped to the prefrontal cortex region [10], the key region implicated in
executive function skills. These six traits are arguably linked to the three theories as they are
components/or derivatives of the theories.
Nearly 30 years after Ivar Lovaas [11] seminal paper received widespread interest
behavioural interventions still dominate as a possible solution to autism across the globe and
in India. Very little importance is given to neuropsychological findings. There is an urgent
need to highlight the importance of potential neuro-cognitive approaches to intervention. The
164
three theories mentioned above have been the guiding principles for some intervention
models [12]. One paper that reviewed the three theories comprehensively [13] has suggested
that future research needs to focus on taking a more developmental and dynamic approach to
studying these theories as a multiple deficit account may help us understand autism.
Indian literature on autism includes references to neurobiology of autism [14] and reviews of
the Indian scene [15].
This article focuses on research in autism neuropsychology, discussing the three theories and
hints at the ways in which they have been incorporated in formulating intervention strategies.
Table No.1 lists broad aspects of cognition and functioning in the Autism Spectrum Disorders
(ASD)
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It is difficult to parse out deficits underlying general developmental delays from those
underlying specific autistic features. The cognitive profile in autism is extremely uneven
(Table 1). While language may be present in an individual, communication can be very
impaired. That a section of the autistic population is intelligent has always been apparent but
intelligence testing has remained a challenge. Research suggests better performance on the
Coloured Progressive Matrices (CPM); our own experience [29] has been that administering
the CPM to those attending special schools is difficult task. Only 20 of 28 children
considered high functioning by teachers could complete the CPM. All scored below average
compared to age matched controls. It is possible that only the more disabled children with
ASD enrol in training centers in India. Indian clinical scenarios too may show fewer children
with ASD in the normal intelligence range. On the other hand, Chakraborti and Fombonne
[24] (Table 1- column Intelligence) suggest that a wider range of able children with socio-
communicative limitations seek professional assistance in some western countries. Box No. 1
lists the definitions of the theories.
The term “theory of mind”(ToM)[5] refers to the ability to explain and predict
behaviour by hypothesizing on the thoughts, feelings and goals of partners.
Executive Functions (EF) has been defined as, “mental operations which enable an
individual to disengage from the immediate context in order to guide behaviour by
reference to mental models or future goals”.[6]
Frith used the term Central Coherence[7] (CC) to describe a characteristic of normal
information processing which is the tendency to draw together diverse information to
construct higher level meaning in context.
167
The Major Cognitive Theories are described below:
I. Theory of Mind Deficits
Baron-Cohen and co-authors[5] had suggested that ToM deficits were caused by a defective
innate cognitive mechanism which in its intact form makes it possible to imagine what goes
on in the mind of others. The roots lie in infants’ strong interest in people as evident in their
attention to human faces and language and their ability to respond to affective expressions
within the first few months of life. Studies of early clinical markers of autism emphasize
problems with affect, orienting and responding to others and attention to language [30]. All
of these indicate profound innate difficulties in relating to other people. There have been
criticisms of the false belief task’s relationship to ToM[31]
Some key findings with regard to ToM have been highlighted in table 2.
The hypothesis of ToM deficits in autism and their relationship with difficulties in social
interactions and communication has been tested over the years. A study [48] conducted with
a test involving recognition of ‘faux pas’ in children showed that this ability developed with
age and that females did better than males. Some high functioning individuals with autism
did learn the ability to recognize ‘faux pas’ but still produced them.
Impaired ToM has been implicated in some forms of higher order social cognition such as
moral judgment[49] in high functioning children with autism (HFA). Deciphering mental
state information from expression in eyes [32] and voice [33] have been studied as
168
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components of ToM. More recent studies have raised doubts about the role of ToM with
regard to such prosodic perceptions. The term prosody includes the ability to appreciate
emotional content based on changes in acoustic parameters of language. Using vocal cues one
study [50] found that HFA children have subtle deficits in deciphering vocal cues compared
to normal controls. However, it also emerged that under high cognitive load, ASD subjects
were slower in recognising all vocal cues. They argue that the pattern of deficits seen is
inconsistent with the ToM account.
Literature has time and again reinforced the existence of the ToM but its relationship to the
core deficits of autism is still under investigation. The well known absence of adequate eye
contact in autism remains the core manifestation of ToM. The lack of interest that children
with autism show in focussing on others’ eyes could well be because they are unable to use
the information being conveyed by eyes leading to the social difficulties they face.
Theory of Mind & Its relation to Language Development
In the early years, language development and ToM seem to be very closely related. Joint
attention, cited as a stage in the development of ToM, is also known to be an essential
precursor for language development. But once language develops and ToM has reached the
stage of false belief understanding, the interface of language and ToM becomes a little
blurred [51]. In one longitudinal study [51], researchers gave false belief tasks, a working
memory task and language tasks tapping different aspects including syntax and semantics to a
group of typically developing preschool children. They found that the relationship between
language and ToM was bidirectional. Two recent studies [34] [35] using various tasks to
assess ToM deficits in ASD, typically developing children and those with deafness have
suggested that there is a different but consistent alteration of sequence of ToM development
in children with ASD. Specifically, they seem to fail the false belief based task even if they
170
pass the hidden emotion task while higher proportion of children from other groups found
hidden emotions more difficult to pass. The second of these studies, while confirming the
findings, has introduced the ‘sarcasm task’ to complete a new ToM scale that can capture
developmental sequences and related variations in children with ASDs. This scale needs to be
validated in different contexts [34] [35]. The exact interface of language and ToM still
requires further study.
Theory of Mind and the Social Motivation Theory of Autism
Seyfarth & Cheney [52] have used the theory of natural selection to explain the evolution of
the ToM. They state that only those individuals, who are sufficiently motivated to attend to
others’ actions and behaviours, learn from it. These are individuals who seek the social
reward of “learning” from others. Another [53] model of social motivation suggests social
orientation and the need to be accepted in the social world as inherent in typically developing
individuals. Thus, while ToM plays an important role in social cognition in autism, it is
currently hard to overlook the argument that it appears to arise from more basic functions of
the brain such as face processing and social drives. It may be an intermediate cognitive
phenotype rather than a primary deficit.
Summary of ToM Deficits in ASD: Over 80% of children with autism fail ToM tasks
though these deficits are not specific to ASD. While the ToM can be used to explain some of
the deficits of autism in the areas of social relations, it fails to account for other features such
as - restricted and repetitive behaviours or savant abilities. The longitudinal sequence of
development of ToM ability may be different in ASD from that in hearing impaired children
or typical development. And it may be dependent on other deficits such as face processing,
social motivation and executive function.
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II. Executive Function
Executive Function (EF) is traditionally used as an umbrella term for functions such as
planning, working memory, impulse control, inhibition and shifting sets, as well as the
initiation and monitoring of action. These functions share the need to disengage from the
immediate environment in order to guide actions.
There are 3 separable but unified components of EF:
1) Attention control: selective attention and sustained attention.
2) Cognitive flexibility: working memory, attention shift, self-monitoring, and conceptual
transfer.
3) Goal setting: initiating, planning and organization, difficulties generating and
implementing strategies for problem solving, and strategic behaviour. Table 3 lists a few
studies relevant to ASD
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The first report of EF deficits in a case of residual state autism reported inflexible problem
solving strategies and perseveration [66]. The Cambridge Neuropsychological Test
Automated Battery (CANTAB) is a computer-administered set of tests developed to examine
specific components of cognition [67]. This was administered to individuals with autism and
normal controls, ranging from 6 to 47 years, matched on age, sex, and full-scale IQ.
Significant group differences were found in performance, with the autism group showing
deficits in planning efficiency and extra-dimensional shifting, relative to controls. Deficits
were found in both lower and higher-IQ individuals with autism across the age range.
Impairments did not predict autism severity or specific autism symptoms, but it was
correlated with adaptive behaviour.
Multitasking was studied in a group of HFA boys [68] by administering the Battersea
Multitask Paradigm along with matched controls. Multitasking involves the ability to
organize and execute different tasks along with a good working memory and all other
components of EF skills. Participants performed poorly compared to controls. Trying to
control for Intellectual Delays and its impact on EF in children with ASD, a recent study has
suggested that impaired flexibility and efficient planning may be more central to ASD as they
are present in children with and without Intellectual Delay [69].
EF and Language Ability
Executive dysfunction and its relation to language ability in verbal school age children with
autism has been examined [70] [71]. Children with autism exhibited deficits across all
domains of EF that were assessed - working memory, inhibitory control and planning.
Children with autism were less developed than the controls in their language skills, but
correlational analyses revealed no specific association between language ability and
executive performance in the autism group. In contrast, executive performance was positively
174
correlated with language ability among controls. This pattern of findings has been interpreted
to mean that executive dysfunction in autism is not directly related to language impairment
per se. There may be an executive failure in the use of language for self-regulation [70][71].
EF & Adaptive Behaviour:
Gilotty et al [72] examined the relationship between EF and adaptive behaviour in children
with ASD. 30 boys and 5 girls (ages 6-17), with a full scale IQ of at least 70 participated in
the study. Two parent questionnaires were used – The Vineland Adaptive Behaviour Scales
and the Behaviour Inventory of Executive Functions. EF impairments were strongly
associated with the deficits in communication, play and social relationships found in children
with autism. The impact of executive impairments on adaptive behaviour and real world
functioning has been seen to increase with age and is more prominent when the ASD subjects
are likely to foray into employment [73]. Yet another recent study that examined the
development of EF and autistic symptoms in HFAs over three points in time confirmed the
impact of EF on adaptive behaviours [74].
EF & Restricted Behaviours:
The relationship between EF and the restricted & repetitive symptoms of Autism was
examined in 17 adults and 17 controls [75]. Cognitive flexibility, working memory and
response inhibition (EF components) were highly related to the restricted and repetitive
symptoms of Autism. Impaired response generation and behavioural inhibition have been
proposed as potential explanations for stereotypical behaviours [76].
ToM & EF
A cross cultural study with Chinese and US preschoolers using EF and ToM tasks was
conducted to determine the relationship between ToM and EF [77]. The EF tasks carried out
were primarily related to inhibition control. The Chinese children out-performed the US
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children on all measures of EF but were not similarly advanced in ToM reasoning.
Nonetheless individual differences in EF predicted ToM reasoning in both cultures
demonstrating that executive functioning is necessary for development of the ToM.
Subsequently their independent impact on adaptive behaviours varies.
Prospective memory is the ability to carry out a task in the future and it can impact on
adaptive functioning. Exploring the independent contributions of EF and ToM deficits to time
based and event based prospective memory tasks, researchers [58] reported that time based
prospective memory deficits are more commonly seen in HFA and ToM had a significant
association with such deficits. Cognitive flexibility did not seem to play a role in this study.
Another recent study that examined the development of EF and autistic symptoms in HFAs
over three points in time confirmed the impact of EF on adaptive behaviours [74].
Summary of Executive Function: Impairments in EF abilities have been widely reported in
children with autism and appear to account for many of the features including the varied
adaptive behaviour profile and restricted, repetitive behaviours. On the other hand, these
deficits fail to show significant relationship with perceptual characteristics of individuals with
autism. To highlight the complexity, even measures of Central Coherence (discussed later)
and restricted and repetitive behaviours themselves have not always related significantly with
each other [78]. Also, executive dysfunction is not specifically associated with autism. It
would be interesting to study why the same fundamental deficit in say, ADHD, leads to
different impairments as in autism. Happe et al [79] while examining the EF profiles among
autism, ADHD and typically developing children found the EF deficits to be less severe but
persistent in autism than ADHD. They report that children with ADHD had more inhibitory
problems while those with autism had difficulties in response selection. However, other
researchers [80][81] have concluded that EF deficits are more profound and generalized in
176
autism. Children with autism show significant deficits in vigilance when compared to
typically developing children. They also had significant deficits in response inhibition,
cognitive flexibility and working memory when compared with ADHD and typically
developing children [80].
III Central Coherence (CC)
Frith [7] used the term CC to describe a characteristic of normal information processing
which is the tendency to draw together diverse information to construct a higher level
meaning in context.
177
In order to directly examine the ability to integrate elements into a whole image, adults
with ASD and normal adults were asked to name a familiar object moving behind a
narrow vertical slit[94]. Pictures were first presented behind the slit at a fast and a slow
speed. Subsequently whole pictures were presented in front of the slit at the fast speed
(full viewing). Both groups were good in the full viewing condition, but those with
autism were significantly poorer in slit viewing. The results were taken to indicate that
individuals with ASD have a deficit in integrating pieces of information received over
time into the whole picture.
The notion of weak central coherence (WCC) refers to a decreased ability in global
processing and an enhanced ability with processing local detail. According to Happe [95]
spared or superior functioning in certain areas cannot be explained by a general deficit;
instead we should consider that individuals with autism have a distinctive cognitive style
that leads to peaks and troughs in performance.
CC & Language Skills:
Linguistic processing in normally intelligent adults with ASD has been explored to test
whether local coherence is impaired [96]. Three tests were used: 1) The Homograph Test
2) Local Coherence Inferences Test and 3) Ambiguous Sentence Test. Results suggest
that individuals on the autism spectrum are impaired in achieving local coherence and
they have a preference not to strive for coherence unless instructed to do so or unless they
make a conscious decision to do so. CC ability appears to have an impact on language
abilities in children with autism.
178
CC & Savant Skills:
The word Savant refers to individuals who despite having severe intellectual impairments
nevertheless show extraordinary skills in a particular cognitive area. Approximately 10%
of individuals with autism have Savant skills thus greatly enhancing its diversity. Half of
all savant people have autism [97]. Detail focussed attention and memory are said to
predispose an individual to special talents both in the general population and in autism.
Since such a large proportion of individuals with savant skills have autism, there is a
strong likelihood of some commonality at the neuronal level and a further understanding
of savant skills could lead us to a better understanding of CC and vice versa.
Summary of Weak Central Coherence theory: The Weak CC theory can be used to
explain the perceptual characteristics of autism. It can be stretched to account for the
savant abilities as well. It may be mentioned here that one study found that better CC in
early years resulted in better ToM while a reciprocal effect was not found [98]. Another
study [99] on typically developing preschoolers found one aspect of CC (visual-spatial)
to be related to different dimensions of executive control. However Booth & Happe
[100], while developing a tool to measure CC through language, found no association of
CC with EF suggesting that the association becomes weaker in the higher order
functioning of language.
Summary of Neuropsychological Findings
While the importance of ToM and its impact on social-communication cannot be ignored,
there seems to be a large body of research pointing to EF as important to understanding
autism. It is not clear how CC factors into everyday adaptive behaviour, although its role
179
in stereotypical and restricted behaviour routines, seem to have good support. It appears
that an understanding of the impact of each of the three deficits on the other two remains
inadequate. One significant longitudinal study [98] attempted to document the impact of
each of these theories on the developmental outcome in high functioning children with
autism. Better CC appears to relate to better ToM though not vice versa. Early EF skills
predicted ToM skills while the reverse was not true. An interesting finding was that while
EF skills and ToM improved with time, performance on CC remained constant. One
report [101] had also found that one aspect of CC (integration) to be related to one aspect
of executive control but the direction of the effect was uncertain.
A growing number of studies looking at the factor structure of autistic traits seem to
indicate the presence of a general autism factor (GAF) with or without a social
communication factor [102]. Neuropsychological explorations into the integrity of the
GAF at a trait level have not been optimally carried out. One recent study [103] has
however cautioned with regard to assumptions underlying such studies and the nature of
broader phenotype measures used. Any neuropsychological model also needs to explain
the global cognitive heterogeneity in autism. On the other hand, some of the known
neuropsychological models are already being applied in interventional research.
Outcomes of such research may further help understand the complex interplay between
various neuropsychological aspects.
Case control studies and neuro-imaging studies to an extent have brought some validation
to the ToM and EF deficits while fMRI studies and reading comprehension have been
used to validate the construct of weak central coherence. The figure below summarizes
181
Significance of Neuropsychological Findings in Autism Intervention
Intervention in autism has traditionally relied on behavioural approaches but in light of
what we know today, we would do well to consider methods which will enable us to
overcome or otherwise compensate for these neuropsychological deficits/differences.
Lovaas’ sensational results created considerable interest in behavioural intervention but
subsequent researchers were unsuccessful in replicating Lovaas’ study [104].
“What Works Clearing House” (WCC) [105] is a report produced by the US Department
of Education on the various effective intervention strategies available. The WCC in 2010
found that the Lovaas Model had positive effects on cognitive development, but did not
have any discernable effect on language and social development or functional abilities of
children with autism. A systematic review of interventions for ASD found “No definitive
evidence suggesting superiority of Lovaas over other active interventions”[106]. While
we are as yet unable to change the way the brain is wired in autism, we could adapt the
way in which we provide inputs and also help support the outputs in order to
accommodate to the differences in the wiring[107]. The Early Start Denver Model
(ESDM) [108] is an intervention model that integrates the behavioural and
developmental-relationship based approach. A randomized control trial using the ESDM
showed that children with autism maintained their rate of growth in adaptive behaviour
after two years of intervention. This promising approach strengthens the importance of
understanding and using neuropsychological approaches to intervention.
Conclusion
Each of the three theories considered here seem to explain some aspects of autism but it
182
is in combination that their explanatory power seems to increase. Language abilities and
EF are necessary for ToM development which in turn is required for narrative abilities to
enable spontaneous conversation. CC in turn is necessary to understand the bigger
picture.
No single deficit may explain all the core symptoms of autism, if one goes by reports of
the less extreme forms of these behaviours being inherited almost entirely independently
of each other within the general population [109]. However, controversies continue about
single core deficit vs. multiple deficits [110, 111]. If the autistic traits show confluence
into single factors in the general population, which are also continually distributed [102],
one tends to imagine that interactions amongst the deficits are more likely. The
possibility of autism being a unitary disorder has been under query for some time now
[112]. If multiple deficits can lead to myriad manifestations of the disorder, intervention
techniques may vary depending on the deficits in each case. The focus of future research
needs to be on the interaction amongst various neuropsychological deficits and their
implications for intervention strategies at different age levels.
183
Appendix
Box 1: Definition of Key terms
REFERENCES
1) American Psychiatric Association. Diagnostic and statistical manual of mental
disorders (5th ed.) Washington, DC: APA, 2013
he term “theory of mind”(ToM)[5] refers to the ability to explain and predict behaviour
by hypothesizing on the thoughts, feelings and goals of partners.
Executive Functions (EF) has been defined as, “mental operations which enable an
individual to disengage from the immediate context in order to guide behaviour by
reference to mental models or future goals”.[6]
Frith used the term Central Coherence[7] (CC) to describe a characteristic of normal
information processing which is the tendency to draw together diverse information to
construct higher level meaning in context.
184
2) CDC. Prevalence of autism spectrum disorders—Autism Spectrum Disorder
Among Children Aged 8 Years – Autism and Developmental Disabilities
Monitoring Network, 11 sites, United States, 2010. In: Surveillance
Summaries, March 28, 2014. 63 (SS02):1–21.
3) Kanner L: Autistic disturbances of affective contact. Nervous Child 1943, 2,
217-250
4) Charman, T., Jones, C. R. G., Pickles, A., Simonoff, E., Baird, G., & Happé,
F. Defining the cognitive phenotype of autism. Brain res 2011; 1380, 10-21.
5) Baron-Cohen S, Leslie AM, & Frith U. Does the autistic child have a "theory
of mind"? Cognition 1985, 21, 37-46
6) Hughes C, Russell J, & Robbins TW: Evidence for executive dysfunction in
autism. Neuropsychologia 1994, 32, 477–492.
7) Frith U, Happe´ F. Autism: beyond “theory of mind”. Cognition 1994, 50
8) Dawson, G., Webb, S., Schellenberg, G. D., Dager, S., Friedman, S., Aylward,
E., & Richards, T. Defining the broader phenotype of autism: Genetic, brain,
and behavioural perspectives. Dev Psychopathol 2002; 14:03, 581-611.
9) Rogers, S. J., & Pennington, B. F. A theoretical approach to the deficits in
infantile autism. Dev Psychopathol 1991; 3:02, 137-162.
10) Happé, F., Briskman, J., & Frith, U. Exploring the cognitive phenotype of
autism: Weak “central coherence” in parents and siblings of children with
autism: I. Experimental tests. J Child Psychol Psychiatry 2001; 42:3, 299-307.
185
11) Lovaas OI: Behavioural treatment and normal educational and intellectual
functioning in young autistic children. J Consult Clin Psychol 1987; 55:3-9.
12) Gutstein SE, Burgess AF & Montfort K. Evaluation of the Relationship
Development Intervention Programme. Autism 2007; 11, 397-411.
13) Rajendran G & Mitchell P: Cognitive theories of autism. Dev Review 2007;
27:2, 224-260.
14) Sinha Vinod et al: Neurobiology of Asperger’s Syndrome: A case study and
overview. Indian J Psychiatry 2001; 43:3, 267-272.
15) Malhotra S, Vikas A: Pervasive developmental disorders: Indian scene. J
Indian Assoc Child Adolesc Ment Health 2005; 1(3):5
16) Goldstein, G., Johnson, C. R., & Minshew, N. J. Attentional processes in
autism.
J Autism Dev Disord 2001; 31:4, 433-440.
17) Hermelin B & Frith U: Psychological studies of childhood autism: can autistic
children make sense of what they see and hear? J of Special Ed 1971, 5, 107-
117.
18) Renner P, Klinger LG, & Klinger M: Implicit and explicit memory in autism:
Is autism an amnesic disorder? J Autism Dev Disord 2000, 30, 3–14.
19) Boucher J, Mayes A, Bigham S: Memory in autistic spectrum disorder.
Psychol Bulletin 2012; 138:3, 458-496.
20) Poirier, M., Martin, J. S., Gaigg, S. B., & Bowler, D. M. Short-term memory
in autism spectrum disorder. J of Abnormal Psychol 2011; 120(1), 247.
186
21) DiGiacomo A & Fombonne E. Parental recognition of developmental
abnormalities in autism. Eur Child Adolesc Psychiatry 1998; 7:131-136.
22) Lewis FA, Murdach BE, & Woodyatt GC. Linguistic abilities in children with
autism spectrum disorders. Res Autism Spectrum Disorders 2007, 1, 85–100.
23) Boucher, J. Research review: structural language in autistic spectrum
disorder–characteristics and causes. J Child Psychol Psychiatry 2012; 53:3,
219-233.
24) Chakrabarti S, & Fombonne E: Pervasive developmental disorders in
preschool children. J American Medical Association 2001; 285: 3093–3099.
25) Dawson M, Soulie`res I, Gernsbacher MA, & Mottron L. The level and nature
of autistic intelligence. Psychol Science 2007; 18: 657–662.
26) Munson J, Dawson G, Sterling L, Beauchaine T, Zhou A, Koehler E, Lord C,
Rogers S, Sigman M, Estes A, Abbott R, and Conners F: Evidence for Latent
Classes of IQ in Young Children With Autism Spectrum Disorder. American
Journal on Mental Retardation 2008, Vol. 113, No. 6, pp. 439-452.
27) Bolte S & Poustka F. The relation between general cognitive level and
adaptive behavior domains in individuals with autism with and without co-
morbid mental retardation. Child Psychiatry Hum Dev 2002; 33:2, 165-172.
28) Perry A, Flanagan HE, Dunn Geier J, & Freeman NL: Brief report: The
Vineland adaptive behavior scales in young children with autism spectrum
disorders at different cognitive levels. J Autism Dev Disord 2009, 39, 1066–
1078.
187
29) Rao V, Raman V, Ashok MV. Issues related to IQ-matched controls in autism
related research accepted for publication, Indian J Psychol Medicine, 2014
30) Dawson G, Meltzoff A, Osterling J, Rinaldi J, & Brown E. Children with
autism fail to orient to naturally occurring social stimuli. J Autism Dev Disord
1998; 28, 479–485.
31) Bloom P and German TP : Two reasons to abandon the false belief task as a
test
of Theory of Mind. Cognition, 2000, 77 : B25 – B31
32) Baron‐Cohen S, Wheelwright S, Hill J, Raste Y, Plumb I. The ‘Reading the
Mind in the Eyes’ Test revised version: a study with normal adults, and adults
with Asperger syndrome or high‐functioning autism. J Child Psychol Psychiatry
2001; 42: 241–51.
33) Rutherford MD, Baron-Cohen S, & Wheelwright S: Reading the mind in the
voice: a study with normal adults and adults with Asperger syndrome and high
functioning autism. J Autism Dev Disord 2002, 32, 189–194.
34) Peterson, Candida C., Henry M. Wellman, and Virginia Slaughter. "The Mind
Behind the Message: Advancing Theory‐of‐Mind Scales for Typically
Developing Children, and Those With Deafness, Autism, or Asperger
Syndrome." Child Dev 2012; 83:2: 469-485.
35) Peterson, C. C., Wellman, H. M., & Liu, D. Steps in Theory‐of‐Mind
Development for Children With Deafness or Autism. Child Dev 2005; 76:2,
502-517.
188
36) Kana, R. K., Libero, L. E., Hu, C. P., Deshpande, H. D., & Colburn, J. S.
Functional brain networks and white matter underlying theory-of-mind in
autism. Soc cognitive affective neuroscience 2014; 9:, 98-105.
37) Baron-Cohen, S., Ring, H. A., Bullmore, E. T., Wheelwright, S., Ashwin, C., &
Williams, S. C. R. The amygdala theory of autism. Neuroscience &
Biobehavioral Reviews 2000; 24:3, 355-364.
38) Ramachandran, V. S., & Oberman, L. M. Broken mirrors: a theory of
autism. Scientific American 2006; 295(5), 62-69.
39) Dahlgren S, Sandberg SA, Hjelmquist E: The non-specificity of theory of mind
deficits: Evidence from children with communicative difficulties. Eur J
Cognitive Psychol 2001; 15:1, 129-155.
40) Bora E, Yucel M, Pantelis C: Theory of Mind Impairment: a distinct trait-
marker for schizophrenia spectrum disorders and bipolar disorder? Acta
Psychiatrica Scandinavica 2009; 120:4, 253-264.
41) Piven J, Palmer P, Jacobi D, Childress D, Arndt S: Broader Autism Phenotype:
Evidence from a family history study of multiple incidence autism families. Am
J Psychiatry 1997; 154, 185-190.
42) Wilson CE, Freeman P, Brock J, Burton AM, Palmero R: Facial Identity
recognition in the Broader Autism Phenotype. PLOS one 2010,
DOI:10.1371/journal.pone.0012876.
189
43) Dalton KM, Nacewicz MB, Alexander LA, Davidson JR: Gaze-fixation, brain
activation and amygdala volume in unaffected siblings of individuals with
autism. Biol Psychiatry 2007; 61:4, 512-520.
44) Dorris L, Espie CAE, Knott F, Salt J. Mind-reading difficulties in the siblings
of people with Asperger’s Syndrome: evidence for a genetic influence in the
abnormal development o a specific cognitive domain. J Child Psychol
Psychiatry 2004; 45:2, 412-418.
45) Meltzoff NA: Understanding the intention of others: Re-enactment of intended
acts by 18-month-old children. Dev Psychol 1995; 31:5, 838-850.
46) Flavell HJ: Theory of Mind Development: Retrospect and Prospect. Merrill-
Palmer Quarterly 2004, 50:3, 274-290.
47) Wellman HM, Cross D, Watson J: Meta-analysis of theory of mind
development: the truth about false belief. Child Dev 2004; 72: 655-684.
48) Baron-Cohen S, O’Riordan M, Stone V, Jones R, & Plaisted K: Recognition of
faux pas by normally developing children and children with Asperger syndrome
or high-functioning autism. J Autism Dev Disord 1999; 29, 407-418.
49) Moran, J. M., Young, L. L., Saxe, R., Lee, S. M., O'Young, D., Mavros, P. L.,
& Gabrieli, J. D. Impaired theory of mind for moral judgment in high-
functioning autism. Proceedings of the National Academy of Sciences
2011; 108:7, 2688-2692.
190
50) Chevallier, C., Noveck, I., Happé, F., & Wilson, D. What's in a voice? Prosody
as a test case for the Theory of Mind account of autism. Neuropsychologia
2011; 49:3, 507-517.
51) Milligan K, Astington JW, & Dack LA: Language and theory of mind: meta-
analysis of the relation between language ability and false-belief understanding.
Child Dev 2007; 78: 622–646.
52) Seyfarth, R. M., & Cheney, D. L. Affiliation, empathy, and the origins of theory
of mind. Proceedings of the National Academy of Sciences
2013;110(Supplement 2), 10349-10356.
53) Chevallier, C., Kohls, G., Troiani, V., Brodkin, E. S., & Schultz, R. T. The
social motivation theory of autism. Trends in cognitive sciences 2012; 16:4,
231-239.
54) Grant DA and Berg E. A behavioral analysis of degree of reinforcement and
ease of shifting to new responses in a Weigl-type card-sorting problem. J Expt
Psychol 1948; 38:404-411.
55) Cambridge Neuropsychological Test Automated Battery, Cambridge Cognition
Ltd, www.cantab.com
56) Gioia GA, Isquith PK, Guy SC and Kenworthy L: Behaviour Rating Inventory
of Executive Functions. Lutz FL: Psychological Assessment Resources, 2000.
57) Geurts, H. M., Verté, S., Oosterlaan, J., Roeyers, H., & Sergeant, J. A. How
specific are executive functioning deficits in attention deficit hyperactivity
disorder and autism?. J Child Psychol Psychiatry 2004; 45:4, 836-854.
191
58) Williams, D., Boucher, J., Lind, S., & Jarrold, C. Time-based and event-based
prospective memory in autism spectrum disorder: the roles of executive
function and theory of mind, and time-estimation. J Autism Dev Disord
2013; 43(7), 1555-1567.
59) Hughes MD, Turkstra SL, Wulfeck BB: Parent and self ratings of executive
function in adolescents with specific language impairments. Int J Language
Comm Disord 2009; 44:6, 901-916.
60) Martinez-Aran A, Vieta E, Colom F, Torrent C, Sanchez-Moreno J, Reinares
M, Benabarre A et al: Cognitive impairment in euthymic bipolar patients:
implications for clinical and functional outcome. Bipolar Disorders 2004, 6:3,
224-232.
61) Semrud-Clikeman M, Walkowiak J, Wilkinson A, Butcher B: Executive
functioning in children with Asperger’s syndrome, ADHD-Combined type,
ADHD-Predominantly inattentive type and controls. J Autism Dev Disord
2010, 40, 1017-1027.
62) Joyce E, Hutton S, Mutsatsa S, Gibbins H, Webb E, Paul S. Executive
Dysfunction in first episode schizophrenia and its relationship to duration of
untreated psychosis: the West London Study. Br J Psychiatry 2002; 181: s38-
s44.
192
63) Huges C, Plumet M, Leboyer M. Towards a cognitive phenotype for autism:
Increased prevalence of executive dysfunction and superior spatial span
amongst siblings of children with autism. J Child Psychol Psychiatry 1999;
40:5, 705-718
64) Wiebe SA, Sheffield T, Nelson JM, Clark CAC, Chevalier N, Epsy KA. The
Structure of Executive Function in 3 year olds. J Expt Child Psychol 2011; 108:
436-452.
65) Best JR, Miller PH, Jones LL. Executive Functions after age 5: Changes and
correlates. Devel Review 2009; 29:3, 180-200.
66) Steel J, Gorman R & Flexman J: Neuropsychiatric testing in an autistic idiot-
savant: evidence for non-verbal abstract capacity. J Am Academy Child
Adolesc Psychiatry 1984; 23, 704-707.
67) Ozonoff S, Cook I, Coon H, Dawson G, Joseph RM, Klin A et al. Performance
on Cambridge Neuropsychological Test Automated Battery subtests sensitive to
frontal lobe function in people with autistic disorder: evidence from the
Collaborative Programs of Excellence in Autism Network. J Autism Dev
Disord 2004; 34(2), 139–150.
68) Mackinlay R, Charman T, & Karmilov-Smith A: High functioning children
with autism spectrum disorder: a novel test of multitasking. Brain Cogn 2006;
61(1), 14–24.
193
69) Panerai, S., Tasca, D., Ferri, R., Genitori D’Arrigo, V., & Elia, M. Executive
Functions and Adaptive Behaviour in Autism Spectrum Disorders with and
without Intellectual Disability. Psychiatry journal 2014.
70) Joseph RM, McGrath LM, Tager-Flusberg H: Executive dysfunction and its
relation to language ability in verbal school-age children with autism. Dev
Neuropsychol 2005; 27:361–378.
71) Liss M, Fein D, Allen D, Dunn M, Feinstein C, Morris R, Waterhouse L, Rapin
I: Executive functioning in high-functioning children with autism. J Child
Psychol Psychiatry 2001; 42:2:261-70.
72) Gilotty L, Kenworthy L, Sirian L, Black DO, Wagner AE: Adaptive skills and
executive function in autism spectrum disorders. Child Neuropsychol 2002; 8,
241.
73) Rosenthal, M., Wallace, G. L., Lawson, R., Wills, M. C., Dixon, E., Yerys, B.
E., & Kenworthy, L. Impairments in real-world executive function increase
from childhood to adolescence in autism spectrum disorders. Neuropsychology
2013; 27:1, 13.
74) Knoch, Kelley. "Early Predictors of Executive Function Abilities in School-
Aged Children with Autism Spectrum Disorders." (2014). Downloaded from:
http://digitalcommons.uconn.edu/cgi/viewcontent.cgi?article=6678&context=di
ssertations
194
75) Lopez BR, Lincoln AJ, Ozonoff S & Lai Z: Examining the relationship between
executive functions and restricted, repetitive symptoms of Autistic Disorder. J.
Autism Dev. Disord. 2005, 35, 445–460.
76) Sayers, N., Oliver, C., Ruddick, L., & Wallis, B. (2011). Stereotyped behaviour
in children with autism and intellectual disability: An examination of the
executive dysfunction hypothesis. J Intellectual Disability Res 2011;55:7, 699-
709.
77) Sabbagh MA, Xu F, Carlson SM, Moses LJ, & Lee K: The development of
executive functioning and theory of mind: a comparison of Chinese and US
preschoolers. Psychol Science 2006; 17, 74–81.
78) South, M., Ozonoff, S., & Mcmahon, W. M. The relationship between
executive functioning, central coherence, and repetitive behaviors in the high-
functioning autism spectrum. Autism 2007; 11(5), 437-451.
79) Happé, F., Booth, R., Charlton, R., & Hughes, C. Executive function deficits
in autism spectrum disorders and attention-deficit/hyperactivity disorder:
Examining profiles across domains and ages. Brain Cogn 2006; 61:1, 25-39.
80) Corbett, B. A., Constantine, L. J., Hendren, R., Rocke, D., & Ozonoff, S.
Examining executive functioning in children with autism spectrum disorder,
attention deficit hyperactivity disorder and typical development. Psychiatry
research 2009; 166:2, 210-222.
195
81) Semrud-Clikeman, M., Walkowiak, J., Wilkinson, A., & Butcher, B. (2010).
Executive functioning in children with Asperger syndrome, ADHD-combined
type, ADHD-predominately inattentive type, and controls. J Autism Dev
Disord, 40(8), 1017-1027.
82) Witkin H, Oltman P, Raskin E & Karp S: A Manual for The Embedded Figures
Test. Consulting Psychologists Press Inc, 1971.
83) Wechsler D: Wechsler Intelligence Scale for Children 3rd Ed. London: The
Psychological Corporation, 1992.
84) Hooper HE: The Hooper Visual Organization Test Manual. Los Angeles:
Western Psychological Services, 1958.
85) Olu-Lafe, O., Liederman, J., & Tager-Flusberg, H. Is the Ability to Integrate
Parts into Wholes Affected in Autism Spectrum Disorder?. J Autism Dev
Disord 2014; 1-9.
86) Van Lang N, Bouma A, Sytema S, Kraijer D & Mineraa R: A comparison of
central coherence skills between adolescents with an intellectual disability with
and without a comorbid disorder in the autism spectrum. Res Dev Disablities
2006; 27:2, 217-226.
87) Ricketts, J., Jones, C. R., Happé, F., & Charman, T. (2013). Reading
comprehension in autism spectrum disorders: The role of oral language and
social functioning. J Autism Dev Disord, 43(4), 807-816.
196
88) Kumar, S. L. Examining the characteristics of visuospatial information
processing in individuals with high-functioning autism. The Yale journal of
biology and medicine 2013, 86:2, 147.
89) Tenconi E, Santanastaso P, Degortes D, Bosello R, Titton F, Mapella D &
Favaro A: Set-shifting abilities, central coherence and handedness in Anorexia
Nervosa patients, their unaffected siblings and healthy controls: exploring
putative endophenotypes. The world journal of biological psychiatry 2010; 11,
813-823.
90) Mardh S: Weak central coherence in patients with Alzheimer’s disease.
Neural Regeneration Res 2013; 8:8, 760-766.
91) Happe F, Briskman J and Frith U. Exploring the cognitive phenotype of
autism: Weak “Central Coherence” in parents and siblings of children with
autism: I Experimental Tests. J Child Psychol Psychiatry 2001; 42:3 299-307
92) Bolte S and Poustka F; The broader cognitive phenotype of autism in parents:
how specific is the tendency for local processing and executive dysfunction? J
Child Psychol Psychiatry 2006; 47:6, 639-645.
93) Johnson SP. How infants learn about the visual world. Cognitive Science
2010; 34:7, 1158-1184
94) Nakano T, Ota H, Kato N, Kitazawa S: Deficit in visual temporal integration
in autism spectrum disorders. Proc. R. Soc. B 2009, 277, 1027–1030.
95) Happe´ F: Autism: cognitive deficit or cognitive style? Trends in Cognitive
Science 1999; 3, 216–222.
197
96) Jolliffe TD, & Baron-Cohen S: Linguistic processing in high functioning
adults with autism or Asperger syndrome: Is local coherence impaired?
Cognition 1999; 71, 149-185.
97) Treffert DA: The Savant Syndrome: an extraordinary condition. A synopsis:
past, present, future. Philosophical Transactions of the Royal Society B 2009;
364, 1351-1357.
98) Pellicano, E. (2010). The Development of Core Cognitive Skills in Autism: A
3‐Year Prospective Study. Child Dev; 81:5, 1400-1416.
99) Pellicano, E., Maybery, M., & Durkin, K. Central coherence in typically
developing preschoolers: does it cohere and does it relate to mindreading and
executive control?. J Child Psychol Psychiatry 2005; 46(5), 533-547.
100) Booth, R., & Happé, F. “Hunting with a knife and… fork”: Examining
central coherence in autism, attention deficit/hyperactivity disorder, and
typical development with a linguistic task. J Expt Child Psychol 2010;107(4),
377-393.
101) Pellicano, E., Maybery, M., Durkin, K., & Maley, A. Multiple cognitive
capabilities/deficits in children with an autism spectrum disorder:“Weak”
central coherence and its relationship to theory of mind and executive control.
Dev Psychopathol 2006; 18:01, 77-98.
102) Rao, V., Thomas, T., Ashok, MV, (under preparation) Factor Analysis of
Autistic Traits Among Indian School Children.
198
103) Gregory, B. L., & Plaisted-Grant, K. C. The autism-spectrum quotient and
visual search: Shallow and deep autistic endophenotypes J Autism Dev Disord
2013; 1-10.
104) Swallows GO and Graupner TD: Intensive behavioural treatment for
children with autism: a research synthesis. J Autism Dev Disord 2005; 32:5,
423-446.
105) What Works Clearinghouse. (2010). WWC intervention report: Lovaas
model of Applied Behavior Analysis. Retrieved from
http://ies.ed.gov/ncee/wwc/pdf/
wwc_lovaas_082410.pdf
106) Ospina, M. B., Krebs Seida, J., Clark, B., Karkhaneh, M., Hartling, L.,
Tjosvold, L., et al. Behavioural and developmental interventions for autism
spectrum disorder: A clinical systematic review. PLoS ONE 2008; 3:11,
e375510.1371/journal.pone.0003755.
107) Williams DL, Minshew NJ: How the Brain Thinks in Autism:
Implications for Language Intervention. ASHA Leader 2010, Vol. 15:8
108) Dawson G, Rogers S, Munson J, Smith M, Winter J, Greenson J,
Donaldson A and Varley J: Randomized, controlled trial of an early
intervention for toddlers with autism: The Early Start Denver Model.
Pediatrics 2010; 125, e17-e23.
199
109) Constantino, J. N., & Todd, R. D. Intergenerational transmission of
subthreshold autistic traits in the general population. Biol psychiatry
2005;57:6, 655-660.
110) Happe F, Ronald A, Plomin R: Time to give up on a single explanation for
autism. Nat Neuroscience 2006; 9:1218-1220.
111) Goodman R: Infantile Autism: A syndrome of multiple primary deficits? J
Autism Dev Disord 1989; 19:3, 409-424.
112) Boucher J: Redefining the concept of autism as a Unitary Disorder:
Multiple Causal Deficits of a single kind? In Fein D (Ed), The
Neuropsychology of Autism New York: Oxford University Press. 2011,
pp.469-482.
Ms. Vanitha S Rao, PhD Scholar; Dr. Ashok V Mysore, Professor; Dr. Vijaya Raman,
Additional Professor of Clinical Psychology, Department of Psychiatry, St. John’s
Medical College Hospital, Bengaluru.