current theoretical & practical issues in autism diagnosis dr. elizabeth sheppard developmental...

Current theoretical & practical Current theoretical & practical

issues in autism diagnosisissues in autism diagnosis

Dr. Elizabeth SheppardDr. Elizabeth Sheppard

Developmental Cognitive

Neuropsychology (C8CLDC)

Child Clinical Neuropsychology

(C8DCHN)

ObjectivesObjectives

Provide background information on Provide background information on autism and ASDautism and ASD

Discuss conceptual issues Discuss conceptual issues surrounding diagnosis of autismsurrounding diagnosis of autism

Discuss approach to possible causes Discuss approach to possible causes of behavioural symptoms of autismof behavioural symptoms of autism

Discuss current thinking & future Discuss current thinking & future challenges on changing prevalence challenges on changing prevalence of ASDof ASD

Childhood disordersChildhood disorders

Acquired – through damage to brainAcquired – through damage to brainDevelopmental - no evidence of Developmental - no evidence of

neurological injury – abnormal neurological injury – abnormal cognitive development i.e. deviant cognitive development i.e. deviant developmental pathdevelopmental pathMay be influenced by various factorsMay be influenced by various factors

GeneticsGeneticsPhysiologyPhysiologyEnvironmentEnvironment

What is autism?What is autism? Autism is characterised by social & non-Autism is characterised by social & non-

social features:social features:Social features regarded as ‘triad of Social features regarded as ‘triad of

impairments’ (Wing & Gould, 1979) in impairments’ (Wing & Gould, 1979) in socialisation, imagination & socialisation, imagination & communicationcommunication

Non-social features – narrow range of Non-social features – narrow range of interests, repetitive behaviour, good interests, repetitive behaviour, good performance on visuospatial tasks, performance on visuospatial tasks, savant skillssavant skills

Current thinking aims to explain a triad Current thinking aims to explain a triad of impairments in social interaction, of impairments in social interaction, communication, & restricted & repetitive communication, & restricted & repetitive interests (DSM-IV, APA, 1994)interests (DSM-IV, APA, 1994)

Autism & Asperger SyndromeAutism & Asperger Syndrome

Autism first described by Kanner (1943) & Autism first described by Kanner (1943) & Asperger (1944)Asperger (1944)

Asperger focused more on children who Asperger focused more on children who were intellectually able – Wing (1981) – were intellectually able – Wing (1981) – ‘Asperger Syndrome’ – subgroup of autism‘Asperger Syndrome’ – subgroup of autism

Asperger differ from autismAsperger differ from autism More intellectually able – must have IQ>70More intellectually able – must have IQ>70 Language onset not delayedLanguage onset not delayed Motor impairments?Motor impairments? Age of onset?Age of onset?

Still controversial - HFA?Still controversial - HFA?

The Autism SpectrumThe Autism Spectrum Autistic spectrum (Wing & Gould, 1979) - Autistic spectrum (Wing & Gould, 1979) -

autism, Asperger Syndrome, atypical autism, Asperger Syndrome, atypical autism & PDD-not otherwise specified autism & PDD-not otherwise specified (plus Rett’s syndrome & Fragile X)(plus Rett’s syndrome & Fragile X)

These known as autism spectrum These known as autism spectrum disorders (or pervasive developmental disorders (or pervasive developmental disorders)disorders)

Individuals who gain a diagnosis of ASD Individuals who gain a diagnosis of ASD (PDD-NOS) may have greater (PDD-NOS) may have greater symptomology in some areas than others, symptomology in some areas than others, mild impairments in several areas or late mild impairments in several areas or late onsetonset

Is there a single cause for Is there a single cause for autistic symptomology?autistic symptomology?

Research on autism has been geared Research on autism has been geared towards explaining triad of impairments towards explaining triad of impairments (socialisation, communication, restricted (socialisation, communication, restricted interests) by a single causeinterests) by a single cause

ASD diagnosis requires all three ASD diagnosis requires all three impairments to be present – but do they impairments to be present – but do they necessarily co-occur?necessarily co-occur?

Ronald et al. (2006) investigated autistic-Ronald et al. (2006) investigated autistic-like traits in general population (no like traits in general population (no diagnosis)diagnosis)

Looked at correlations between social, Looked at correlations between social, communication impairments, & restricted communication impairments, & restricted interestsinterests


Low-to-modest correlations in 3 core Low-to-modest correlations in 3 core areas:areas: Social & communication r=0.2-0.4Social & communication r=0.2-0.4 Communication & restricted behaviour r=0.3-Communication & restricted behaviour r=0.3-

0.40.4 Social & restricted behaviour r=0.1-0.3Social & restricted behaviour r=0.1-0.3

Considerable number of children showed Considerable number of children showed impairments in just one area:impairments in just one area: 59% those with social impairments59% those with social impairments, only , only had had

social impairmentssocial impairments 10% all children had one impairment only10% all children had one impairment only

This implies there are 3 dimensions of This implies there are 3 dimensions of impairment that are relatively impairment that are relatively independentindependent


Social impairments

Communication impairments

Restricted interests

Autism

Just language difficulties = pragmatic language impairmentJust language difficulties = pragmatic language impairmentLanguage + social difficulties =PDD-NOS (or atypical autism)Language + social difficulties =PDD-NOS (or atypical autism)


Genetic evidenceGenetic evidenceTwin studies suggest each aspect of Twin studies suggest each aspect of

triad highly heritable triad highly heritable However, most genetic effects are However, most genetic effects are

specific - act on just one part of triad specific - act on just one part of triad (Ronald et al., 2006)(Ronald et al., 2006)

Family studies investigating broader Family studies investigating broader phenotype (subclinical manifestations) phenotype (subclinical manifestations) often find relatives showing only often find relatives showing only isolated traits (e.g. Piven et al., 1997)isolated traits (e.g. Piven et al., 1997)


If these dimensions independent, may If these dimensions independent, may explain heterogeneity observable in explain heterogeneity observable in populations with autism (Happpopulations with autism (Happé et al., é et al., 2006)2006)

May also be individuals with isolated May also be individuals with isolated impairments in one part of triad who fit no impairments in one part of triad who fit no diagnosis at present – need to meet their diagnosis at present – need to meet their needs in future – first step may be to start needs in future – first step may be to start measuring the three aspects of the triad measuring the three aspects of the triad separatelyseparately

Impact on research at cognitive, biological Impact on research at cognitive, biological & genetic levels & for treatment& genetic levels & for treatment

Prevalence of autismPrevalence of autism

Prevalence of autism first estimated at Prevalence of autism first estimated at 0.4/1000 (Lotter, 1966)0.4/1000 (Lotter, 1966)

More recent studies estimate autism rates More recent studies estimate autism rates as 2-4/1000; and 6-7/1000 for all ASDs as 2-4/1000; and 6-7/1000 for all ASDs (Baird et al., 2000; Bertrand et al., 2001; (Baird et al., 2000; Bertrand et al., 2001; Chakrabarti & Fombonne, 2001)Chakrabarti & Fombonne, 2001)

10-fold increase?10-fold increase? So is autism increasing within the So is autism increasing within the

population?population?


Possible reasons for increasePossible reasons for increase1)1) Increase is real – need to explain why. Increase is real – need to explain why.

Introduction of the MMR vaccine? No Introduction of the MMR vaccine? No research supports temporal association research supports temporal association (e.g. Dales et al., 2001) & no plausible (e.g. Dales et al., 2001) & no plausible causal explanation (e.g. Halsey et al., causal explanation (e.g. Halsey et al., 2001)2001)

2)2) Artefacts producing false positive Artefacts producing false positive diagnosis e.g. overexpansion of diagnosis e.g. overexpansion of diagnostic category – hard to prove as no diagnostic category – hard to prove as no litmus test (genetic marker)litmus test (genetic marker)


Possible reasons for increasePossible reasons for increase3) 3) The current rate is correct but there The current rate is correct but there

has not been an increase – has not been an increase – diagnostic boundaries have changed diagnostic boundaries have changed inclusion of spectruminclusion of spectrumIncreasing recognition of comorbidity (e.g. Increasing recognition of comorbidity (e.g.

Downs, Tourette syndrome, cerebral palsy)Downs, Tourette syndrome, cerebral palsy)Improvements in case-finding methodsImprovements in case-finding methodsPopulations sampledPopulations sampledIncreased public awarenessIncreased public awareness


Concurrent decrease in children Concurrent decrease in children registered as having mental registered as having mental retardation (Croen et al., 2002)retardation (Croen et al., 2002)

Estimates of those with ASD with Estimates of those with ASD with IQ>70 now 50-80% - implies rise in IQ>70 now 50-80% - implies rise in intellectually able individuals intellectually able individuals diagnoseddiagnosed

70-90% those with ASD diagnoses 70-90% those with ASD diagnoses were malewere male

Prevalence of autismPrevalence of autism How might we determine whether How might we determine whether

prevalence is increasing?prevalence is increasing? Cohort study – e.g. comparing 25-yr-olds & Cohort study – e.g. comparing 25-yr-olds &

40-yr-olds. But diagnosis less reliable in 40-yr-olds. But diagnosis less reliable in adults & sampling difficultiesadults & sampling difficulties

Improve methods of measurement – this will Improve methods of measurement – this will be linked to our conceptualisation of ASDsbe linked to our conceptualisation of ASDs

Prospective study of ‘at risk’ children e.g. Prospective study of ‘at risk’ children e.g. siblings of those already diagnosed with siblings of those already diagnosed with autism (Wing & Potter, 2002) – but these autism (Wing & Potter, 2002) – but these may differ from individuals where genetic risk may differ from individuals where genetic risk is loweris lower

SummarySummary Autism is not a single condition but rather Autism is not a single condition but rather

there is a spectrum of conditionsthere is a spectrum of conditions The core behavioural features observed in The core behavioural features observed in

autism are actually relatively independent autism are actually relatively independent & each can be observed in isolation – & each can be observed in isolation – related conditions (e.g. PLI) may reflect related conditions (e.g. PLI) may reflect expression of just one of these featuresexpression of just one of these features

Autism is apparently increasing in Autism is apparently increasing in prevalence – this is likely due to advances prevalence – this is likely due to advances in understanding/diagnosis rather than a in understanding/diagnosis rather than a true increasetrue increase

ReferencesReferences American Psychiatric Association. (1994). American Psychiatric Association. (1994). Diagnostic and statistical manual of Diagnostic and statistical manual of

mental disordersmental disorders (4th edn.). Washington DC: American Psychiatric Association. (4th edn.). Washington DC: American Psychiatric Association. Asperger, H. (1944). Die "Autistischen Psychopathen" im kindesalter. Asperger, H. (1944). Die "Autistischen Psychopathen" im kindesalter. Archivfur Archivfur

Psychiatrie und Nervenkrankheiten, 117,Psychiatrie und Nervenkrankheiten, 117, 76-136. 76-136. Baird, G., Charman, T., Baron-Cohen, S., Swettenham, J., Wheelwright, S., & Drew, A. Baird, G., Charman, T., Baron-Cohen, S., Swettenham, J., Wheelwright, S., & Drew, A.

(2000). A screening instrument for autism at 18 months of age: a siex-year follow-(2000). A screening instrument for autism at 18 months of age: a siex-year follow-up study. up study. Journal of the American Academy of Child and Adolescent Psychiatry, 39,Journal of the American Academy of Child and Adolescent Psychiatry, 39, 694-702.694-702.

Bertrand, J., Mars, A., Boyle, C., Bove, F., Yeargin-Allsopp, M., & Decoufle, P. (2001). Bertrand, J., Mars, A., Boyle, C., Bove, F., Yeargin-Allsopp, M., & Decoufle, P. (2001). Prevalence of autism in a United States population: The Brick Township, New Jersey, Prevalence of autism in a United States population: The Brick Township, New Jersey, investigation. investigation. Pediatrics, 108,Pediatrics, 108, 1155-1161. 1155-1161.

Bishop, D. V. M., & Norbury, C. F. (2002). Exploring the borderlands of autistic Bishop, D. V. M., & Norbury, C. F. (2002). Exploring the borderlands of autistic disorder and specific language impairment: a study using standardised diagnostic disorder and specific language impairment: a study using standardised diagnostic instruments. instruments. Journal of Child Psychology and Psychiatry, 43Journal of Child Psychology and Psychiatry, 43, 917-929., 917-929.

Chakrabarti, S. & Fombonne, E. (2001). Pervasive developmental disorders in Chakrabarti, S. & Fombonne, E. (2001). Pervasive developmental disorders in preschool children. preschool children. Journal of the American Medical Association, 285,Journal of the American Medical Association, 285, 3093-3099. 3093-3099.

Charman, T. (2002). The prevalence of autism spectrum disorders: recent evidence Charman, T. (2002). The prevalence of autism spectrum disorders: recent evidence and future challenges. and future challenges. European Journal of Child & Adolescent Psychiatry, 11,European Journal of Child & Adolescent Psychiatry, 11, 249- 249-256. 256.

Croen, L., Grether, J., & Hoogstrate, J. (2002). The changing prevalence of autism in Croen, L., Grether, J., & Hoogstrate, J. (2002). The changing prevalence of autism in California. California. Journal of Autism and Developmental Disorders, 32,Journal of Autism and Developmental Disorders, 32, 207-215. 207-215.

Dales, L., Hammer, S. J., & Smith, N. J. (2001). Time trends in autism and MMR Dales, L., Hammer, S. J., & Smith, N. J. (2001). Time trends in autism and MMR immunization coverage in California. immunization coverage in California. Journal of the American Medical Association, Journal of the American Medical Association, 285,285, 1183-1185. 1183-1185.

ReferencesReferences Halsey, N. A., Hyman, S. L. & the Conference Writing Panel (2001). Measles-mumps-Halsey, N. A., Hyman, S. L. & the Conference Writing Panel (2001). Measles-mumps-

rubella vaccine and autism spectrum disorders: report from the new challenges in rubella vaccine and autism spectrum disorders: report from the new challenges in childhood immunizations conference convened in Oak Brook, Illinois, June 12-13, childhood immunizations conference convened in Oak Brook, Illinois, June 12-13, 2000. 2000. Pediatrics, 107,Pediatrics, 107, e84. e84.

HappHappé, F., Ronald, A., & Plomin, R. (2006). Time to give up on a single explanation é, F., Ronald, A., & Plomin, R. (2006). Time to give up on a single explanation for autism. for autism. Nature Neuroscience, 9Nature Neuroscience, 9, 1218-1220, 1218-1220

Kanner, L. (1943). Autistic disturbance of affective contact. Kanner, L. (1943). Autistic disturbance of affective contact. Nervous Child, 2,Nervous Child, 2, 217- 217-250. Reprinted in L. Kanner (1973). 250. Reprinted in L. Kanner (1973). Childhood psychosis: Initial studies and new Childhood psychosis: Initial studies and new insights.insights. New York: John Wiley & Sons. New York: John Wiley & Sons.

Lotter, V. (1966). Epidemiology of autistic conditions in young children. Lotter, V. (1966). Epidemiology of autistic conditions in young children. Social Social Psychiatry, 1,Psychiatry, 1, 124-137. 124-137.

Piven, J., Palmer, P., Jacobi, D., Childress, D., & Arndt, S. (1997). Broader autism Piven, J., Palmer, P., Jacobi, D., Childress, D., & Arndt, S. (1997). Broader autism phenotype: Evidence from a family history of multiple-incidence autism families. phenotype: Evidence from a family history of multiple-incidence autism families. American Journal of Psychiatry, 154,American Journal of Psychiatry, 154, 185-190. 185-190.

Ronald, A. et al. (2006). Genetic heterogeniety between the three components of Ronald, A. et al. (2006). Genetic heterogeniety between the three components of the autism spectrum: A twin study. the autism spectrum: A twin study. Journal of the American Academy of Child & Journal of the American Academy of Child & Adolescent Psychiatry, 45,Adolescent Psychiatry, 45, 691-699. 691-699.

Wing, L. (1981). Asperger's syndrome: A clinical account. Wing, L. (1981). Asperger's syndrome: A clinical account. Psychological Medicine, Psychological Medicine, 11,11, 115-129. 115-129.

Wing, L., & Gould, J. (1979). Severe impairments of social interaction and associated Wing, L., & Gould, J. (1979). Severe impairments of social interaction and associated abnormalities in children: Epidemiology and classification. abnormalities in children: Epidemiology and classification. Journal of Autism and Journal of Autism and Developmental Disorders, 9,Developmental Disorders, 9, 11-29. 11-29.

Wing, L., & Potter, D. (2002). The epidemiology of autistic spectrum disorders: Is the Wing, L., & Potter, D. (2002). The epidemiology of autistic spectrum disorders: Is the prevalence rising? prevalence rising? Mental Retardation and Developmental Disabilities Reviews, 8Mental Retardation and Developmental Disabilities Reviews, 8, , 151-161.151-161.

Autism: A Disorder of Autism: A Disorder of Executive Function?Executive Function?

Dr. Elizabeth SheppardDr. Elizabeth Sheppard

Developmental Cognitive

Neuropsychology (C8CLDC)

Child Clinical Neuropsychology

(C8DCHN)

ObjectivesObjectives

Discuss evidence for autism as Discuss evidence for autism as disorder of EFdisorder of EF

Evidence comes from:Evidence comes from:Behavioural evidence Behavioural evidence Cognitive testing – is performance Cognitive testing – is performance

normal on tasks that involve one or normal on tasks that involve one or more EF?more EF?

Biological studies – what brain regions Biological studies – what brain regions are implicated?are implicated?

Talk about problems with EF account Talk about problems with EF account of autismof autism

Neuropsychological StudiesNeuropsychological Studies

The goal of neuropsychological The goal of neuropsychological studies is to establish the primary studies is to establish the primary deficit in each disorder.deficit in each disorder.

A PRIMARY deficit needs to:A PRIMARY deficit needs to:Be universalBe universalBe specific (Discriminant validity)Be specific (Discriminant validity)Be necessary and sufficient to cause Be necessary and sufficient to cause

symptoms of the disordersymptoms of the disorder

Is autism a disorder of Is autism a disorder of executive function?executive function?

Major proponents – Russell, Ozonoff etc.Major proponents – Russell, Ozonoff etc. This view argues that ED underlies many This view argues that ED underlies many

of the key features of ASD especially of the key features of ASD especially rigidity & perseverationrigidity & perseveration

These caused by difficulties initiating new These caused by difficulties initiating new non-routine actions & tendency to be non-routine actions & tendency to be stuck in given task setstuck in given task set

Strong liking for repetitive behaviour & Strong liking for repetitive behaviour & elaborate rituals – benefit from prompts & elaborate rituals – benefit from prompts & externally provided structures which externally provided structures which initiate routines or help to switch setinitiate routines or help to switch set

Cognitive evidence of EF Cognitive evidence of EF deficits in autismdeficits in autism

Stimulus overselectivityStimulus overselectivity – tendency to – tendency to respond only to a subset of environmental respond only to a subset of environmental cues which are often irrelevant (Lovaas et cues which are often irrelevant (Lovaas et al., 1979).al., 1979).

PerseverationPerseveration– continue to respond to only – continue to respond to only one stimulus dimension even after one stimulus dimension even after hundreds of trials which were not hundreds of trials which were not rewarded.(Koegel & Schreibman, 1977; rewarded.(Koegel & Schreibman, 1977; Boucher,1977) Boucher,1977)

Strict rule adherenceStrict rule adherence - sequencing stimuli - sequencing stimuli (Frith,1972; Boucher, 1977)(Frith,1972; Boucher, 1977)


Planning – Deficits Planning – Deficits generally found on generally found on planning as indexed by planning as indexed by Tower of Hanoi (e.g. Tower of Hanoi (e.g. Ozonoff et al., 1991)Ozonoff et al., 1991)

Mental flexibility – often Mental flexibility – often assessed with WCST – assessed with WCST – individuals with autism individuals with autism show deficits when show deficits when necessary to shift necessary to shift response set i.e. response set i.e. perseverate (e.g. Prior & perseverate (e.g. Prior & Hoffman, 1990)Hoffman, 1990)

Inhibition – individuals Inhibition – individuals with autism appear with autism appear unimpaired on unimpaired on measures e.g. Stroop measures e.g. Stroop task. task.

But show difficulties on But show difficulties on Russell’s ‘windows Russell’s ‘windows task’ (e.g. Hughes & task’ (e.g. Hughes & Russell, 1993). Russell Russell, 1993). Russell argues individuals with argues individuals with autism fail tests of EF if autism fail tests of EF if no clear rationaleno clear rationale



Generativity – capacity to generate novel ideas & Generativity – capacity to generate novel ideas & behaviours spontaneously behaviours spontaneously

Lewis & Boucher (1991) – drawings of children Lewis & Boucher (1991) – drawings of children with autism showed greater degree of thematic with autism showed greater degree of thematic relatednessrelatedness

Boucher (1988) – children with autism deficits in Boucher (1988) – children with autism deficits in producing miscellaneous wordsproducing miscellaneous words

Jarrold et al. (1996) – impairment in spontaneous Jarrold et al. (1996) – impairment in spontaneous production of pretenceproduction of pretence

Working memory – Bennetto et al. – individuals Working memory – Bennetto et al. – individuals with autism impaired in tests of working memory with autism impaired in tests of working memory but not other types of memory. But but not other types of memory. But Geurts et al. Geurts et al. (2004)(2004) found no working memory deficits in autismfound no working memory deficits in autism


Review of studies - Review of studies - Pennington and Pennington and Ozonoff (1996)Ozonoff (1996)

13/14 studies found deficits in autism on 13/14 studies found deficits in autism on at least one measure of EFat least one measure of EF

Found those with autism poorer than Found those with autism poorer than comparison participants on 25/32 (78%) comparison participants on 25/32 (78%) tasks used across studiestasks used across studies

Hill (2004) – another review of studies – Hill (2004) – another review of studies – concluded widespread impairments in concluded widespread impairments in planning & perseveration in autism, but planning & perseveration in autism, but perhaps not inhibitionperhaps not inhibition

Primacy of EF deficitsPrimacy of EF deficits Some argue EF allows TOM to develop Some argue EF allows TOM to develop

(e.g. Ozonoff, 1997) – others say capacity (e.g. Ozonoff, 1997) – others say capacity to represent mental states needed for EF to represent mental states needed for EF (e.g. Perner, 1998)(e.g. Perner, 1998)

EF deficits in high and low ability EF deficits in high and low ability individuals with autism but not TOM individuals with autism but not TOM (Ozonoff et al., 1991) (Ozonoff et al., 1991)

Correlations between EF and TOM Correlations between EF and TOM performance and EF predicts TOM better performance and EF predicts TOM better than vice versa (Hughes, 1998)than vice versa (Hughes, 1998)

ButBut TOM tasks may also have exec TOM tasks may also have exec component - complexcomponent - complex

Biological evidence for Ex Biological evidence for Ex Dysfunction in autismDysfunction in autism

More evidence for More evidence for functionalfunctional abnormalities abnormalities than than structuralstructural abnormalities. abnormalities.

Structural/neuroanatomical - some Structural/neuroanatomical - some abnormalities found in the :abnormalities found in the : limbic system (Bauman & Kemper, 1985) limbic system (Bauman & Kemper, 1985) Cerebellum (Bauman & Kemper, 1988)Cerebellum (Bauman & Kemper, 1988) parietal lobes (Courchesne et al., 1988)parietal lobes (Courchesne et al., 1988) temporal lobes (Hetzler & Griffin, 1981)temporal lobes (Hetzler & Griffin, 1981) ventricle system (Gaffney et al., 1989)ventricle system (Gaffney et al., 1989) orbitofrontal cortex (Salmond et al., 2003)orbitofrontal cortex (Salmond et al., 2003)

But little evidence for structural But little evidence for structural abnormalities in PFCabnormalities in PFC


Indirect link between frontal function & EDIndirect link between frontal function & ED Some argue ED is consequence of medial Some argue ED is consequence of medial

temporal lobe functional abnormalities temporal lobe functional abnormalities Impairments in prefrontal function seen as Impairments in prefrontal function seen as

consequence of this – differences arise consequence of this – differences arise from severity of abnormality (e.g. Ohnishi from severity of abnormality (e.g. Ohnishi et al., 2000)et al., 2000)

Consequences only become apparent Consequences only become apparent when frontal lobes maturewhen frontal lobes mature


Direct link between frontal lobe function Direct link between frontal lobe function & ED& ED

Dysfunctional integration of frontal lobes Dysfunctional integration of frontal lobes with rest of brain/ abnormal development with rest of brain/ abnormal development in neuronal sophistication/ abnormal in neuronal sophistication/ abnormal myelinisation myelinisation

Findings of delayed postnatal maturation Findings of delayed postnatal maturation of frontal lobes (Zilbovicius et al, 1995) & of frontal lobes (Zilbovicius et al, 1995) & reduced functional connectivity of frontal reduced functional connectivity of frontal cortex with other cortical & subcortical cortex with other cortical & subcortical regions supports this (Luna et al., 2002) regions supports this (Luna et al., 2002)


Koshino et al. (2005) – Koshino et al. (2005) – group with autism group with autism showed reduced showed reduced activation in left activation in left dorsolateral prefrontal dorsolateral prefrontal cortex during working cortex during working memory taskmemory task

SPECT, PET, EEG studies show evidence of SPECT, PET, EEG studies show evidence of unusual function in the frontal areas inunusual function in the frontal areas in individuals with ASD (George et al., 1992;individuals with ASD (George et al., 1992; Horwitz et al., 1988; Dawson et al., 1993)Horwitz et al., 1988; Dawson et al., 1993)

Broader phenotype studies – Broader phenotype studies – investigate presence of autistic investigate presence of autistic features in relatives of those with features in relatives of those with conditioncondition

Deficits in planning & mental Deficits in planning & mental flexibility characterise broader flexibility characterise broader phenotype (e.g. Hughes et al., 1997)phenotype (e.g. Hughes et al., 1997)


Problems for the EF account of Problems for the EF account of autismautism

Although there are similarities between Although there are similarities between autism & children with acquired frontal autism & children with acquired frontal lesions, they aren’t the samelesions, they aren’t the same

Question over universality – some studies Question over universality – some studies have not identified deficits in participants have not identified deficits in participants e.g. Minshew et al., 1992 e.g. Minshew et al., 1992

Specificity – ED & frontal metaphor used Specificity – ED & frontal metaphor used for other developmental disorders e.g. for other developmental disorders e.g. Tourette syndrome, ADHD – characteristics Tourette syndrome, ADHD – characteristics of these different from autism. Need to of these different from autism. Need to explain this (more next week!)explain this (more next week!)

SummarySummary

Evidence for autism as executive Evidence for autism as executive disorder at cognitive & biological disorder at cognitive & biological levelslevelsDeficits in planning & mental flexibilityDeficits in planning & mental flexibilityFrontal lobe abnormalities Frontal lobe abnormalities

Questions over primacy, universality Questions over primacy, universality & specificity of EF deficits in autism & specificity of EF deficits in autism

ReferencesReferences Bauman, M., & Kemper, T. L. (1985). Histoanatomic observations of the brain in Bauman, M., & Kemper, T. L. (1985). Histoanatomic observations of the brain in

early infantile autism. early infantile autism. Neurology, 35,Neurology, 35, 866-874. 866-874. Bauman, M., & Kemper, T. L. (1988). Limbic and cerebellar abnormalities: Bauman, M., & Kemper, T. L. (1988). Limbic and cerebellar abnormalities:

Consistent findings in infantile autism. Consistent findings in infantile autism. Journal of Neuropathology and Experimental Journal of Neuropathology and Experimental Neurology, 47,Neurology, 47, 369. 369.

Bennetto, L., Pennington, B. F., & Rogers, S. J. (1996). Intact and impaired memory Bennetto, L., Pennington, B. F., & Rogers, S. J. (1996). Intact and impaired memory functions in autism. functions in autism. Child Development, 67,Child Development, 67, 1816-1835. 1816-1835.

Boucher, J. (1977). Alternation and sequencing behavior and the response to novelty Boucher, J. (1977). Alternation and sequencing behavior and the response to novelty in autistic children. in autistic children. Journal of Child Psychology & Psychiatry, 18,Journal of Child Psychology & Psychiatry, 18, 67-72. 67-72.

Boucher, J. (1988). Word fluency in high-functioning autistic children. Boucher, J. (1988). Word fluency in high-functioning autistic children. Journal of Journal of Autism and Developmental Disorders, 18,Autism and Developmental Disorders, 18, 637-645. 637-645.

Courchesne, E., Yeung-Courchesne, R., Press, G. A., Hesselink, J. R., & Jernigan, T. L. Courchesne, E., Yeung-Courchesne, R., Press, G. A., Hesselink, J. R., & Jernigan, T. L. (1988). Hypoplasia of cerebellar vermal lobule-Vi and lobule-Vii in autism. (1988). Hypoplasia of cerebellar vermal lobule-Vi and lobule-Vii in autism. New New England Journal of Medicine, 318,England Journal of Medicine, 318, 1349-1354. 1349-1354.

Dawson, G., Klinger, L. G., Panagiotides, H., & Lewy, A. (1993). Dawson, G., Klinger, L. G., Panagiotides, H., & Lewy, A. (1993). Electrophysiological Electrophysiological evidence for frontal lobe involvement in the social impairments of individuals with evidence for frontal lobe involvement in the social impairments of individuals with autism.autism. Paper presented at biennial meeting for SRCD, New Orleans, LA, 25-28 Paper presented at biennial meeting for SRCD, New Orleans, LA, 25-28 March.March.

Frith, U. (1972) Cognitive mechanisms in autism: experiments with color and tone Frith, U. (1972) Cognitive mechanisms in autism: experiments with color and tone sequence production. sequence production. Journal of Autism and Child Schizophrenia, 2Journal of Autism and Child Schizophrenia, 2, 160-173., 160-173.

Gaffney, G. R., Kuperman, S., Tsai, L. Y., & Minchin, S. (1989). Forebrain structure in Gaffney, G. R., Kuperman, S., Tsai, L. Y., & Minchin, S. (1989). Forebrain structure in autism. autism. Journal of the American Academy of Child and Adolescent Psychiatry, 28,Journal of the American Academy of Child and Adolescent Psychiatry, 28, 534-537.534-537.

George, M. S., Costa, D. C., Kouris, K., Ring, H. A., & Ell, P. J. (1992). Cerebral blood George, M. S., Costa, D. C., Kouris, K., Ring, H. A., & Ell, P. J. (1992). Cerebral blood flow abnormalities in adults with infantile autism. flow abnormalities in adults with infantile autism. Journal of Nervous & Mental Journal of Nervous & Mental Disease, 180Disease, 180, 413-417., 413-417.

Guerts, H. M., Verté, S., Oosterlaan, J., Roeyers, H., & Sergeant, J. A. (2004). How Guerts, H. M., Verté, S., Oosterlaan, J., Roeyers, H., & Sergeant, J. A. (2004). How specific are executive functioning deficits in attention deficit hyperactivity disorder specific are executive functioning deficits in attention deficit hyperactivity disorder and autism? and autism? Journal of Child Psychology and Psychiatry, 45, Journal of Child Psychology and Psychiatry, 45, 836-854836-854..

Hetzler, B. E., & Griffiin, J. L. (1981). Infantile autism and the temporal lobe of the Hetzler, B. E., & Griffiin, J. L. (1981). Infantile autism and the temporal lobe of the brain. brain. Journal of Autism and Developmental Disorders, 11,Journal of Autism and Developmental Disorders, 11, 317-330. 317-330.

Hill, E. L. (2004). Executive dysfunction in autism. Hill, E. L. (2004). Executive dysfunction in autism. Trends in Cognitive Sciences, 8,Trends in Cognitive Sciences, 8, 26-32.26-32.

Hill, E. L. (2004). Evaluating the theory of executive dysfunction in autism. Hill, E. L. (2004). Evaluating the theory of executive dysfunction in autism. Developmental Review, 24,Developmental Review, 24, 189-233. 189-233.

Horwitz, B., Rumsey, J. M., Grady, C. L., & Rapoport, S. I. (1988). The cerebral Horwitz, B., Rumsey, J. M., Grady, C. L., & Rapoport, S. I. (1988). The cerebral metabolic landscape in autism: Intercorrelations of regional glucose utilization. metabolic landscape in autism: Intercorrelations of regional glucose utilization. Archives of Neurology, 45,Archives of Neurology, 45, 749-755. 749-755.

Hughes, C. (1998). Finding your marbles: Does preschoolers’ strategic behavior Hughes, C. (1998). Finding your marbles: Does preschoolers’ strategic behavior predict later understanding of mind? predict later understanding of mind? Developmental Psychology, 34,Developmental Psychology, 34, 1326-1339. 1326-1339.

Hughes, C., & Russell, J. (1993). Autistic children’s difficulty with mental Hughes, C., & Russell, J. (1993). Autistic children’s difficulty with mental disengagement from an object: Its implications for theories of autism. disengagement from an object: Its implications for theories of autism. Developmental Psychology, 29,Developmental Psychology, 29, 498-510. 498-510.

Hughes, C. et al. (1997). Executive function in parents of children with autism. Hughes, C. et al. (1997). Executive function in parents of children with autism. Psychological Medicine, 27,Psychological Medicine, 27, 209-220. 209-220.

Jarrold, C., Boucher, J., & Smith, P. K. (1996). Generativity deficits in pretend play in Jarrold, C., Boucher, J., & Smith, P. K. (1996). Generativity deficits in pretend play in autism. autism. British Journal of Developmental Psychology, 14British Journal of Developmental Psychology, 14, 275-300., 275-300.

Koegel, R. L., & Schreibman, L. (1977). Teaching autistic children to respond to Koegel, R. L., & Schreibman, L. (1977). Teaching autistic children to respond to simultaneous multiple cues. simultaneous multiple cues. Journal of Experimental Child Psychology, 24,Journal of Experimental Child Psychology, 24, 299-311. 299-311.

Koshino, H., Carpenter, P. A., Minshew, N. J., Cherassky, V. L., Keller, T. A., & Just, M. Koshino, H., Carpenter, P. A., Minshew, N. J., Cherassky, V. L., Keller, T. A., & Just, M. A. (2005). Functional connectivity in an fMRI working memory task with high-A. (2005). Functional connectivity in an fMRI working memory task with high-functioning autism. functioning autism. Neuroimage, 24Neuroimage, 24, 810-821. , 810-821.

Lewis, V., & Boucher, J. (1991). Skill, content and generative strategies in autistic Lewis, V., & Boucher, J. (1991). Skill, content and generative strategies in autistic children’s drawings. children’s drawings. British Journal of Developmental Psychology, 9, British Journal of Developmental Psychology, 9, 393-416.393-416.

Lovaas, O. I., Koegel, R. L., & Schreibman, L. (1979). Stimulus overselectivity in Lovaas, O. I., Koegel, R. L., & Schreibman, L. (1979). Stimulus overselectivity in autism: A review of research. autism: A review of research. Psychological Bulletin, 86,Psychological Bulletin, 86, 1236-1254. 1236-1254.

Luna, B. et al. (2002). Neocortical system abnormalities in autism. An fMRI study of Luna, B. et al. (2002). Neocortical system abnormalities in autism. An fMRI study of spatial working memory. spatial working memory. Neurology, 59,Neurology, 59, 834-840. 834-840.

Minshew, N. J., Goldstein, G., Muenz, L. R., & Payton, L. R. (1992). Minshew, N. J., Goldstein, G., Muenz, L. R., & Payton, L. R. (1992). Neuropsychological functioning in nonmentally retarded autistic individuals. Neuropsychological functioning in nonmentally retarded autistic individuals. Journal Journal of Clinical and Experimental Neuropsychology, 14,of Clinical and Experimental Neuropsychology, 14, 749-761. 749-761.

Ohnishi, T. et al. (2000). Abnormal regional cerebral blood flow in childhood autism. Ohnishi, T. et al. (2000). Abnormal regional cerebral blood flow in childhood autism. Brain, 123,Brain, 123, 1838-1844. 1838-1844.

Ozonoff, S. (1997). Components of executive function in autism and other disorders. Ozonoff, S. (1997). Components of executive function in autism and other disorders. In J. Russell (ed.). In J. Russell (ed.). Autism as an Executive Disorder.Autism as an Executive Disorder. Oxford: OUP. Oxford: OUP.

Ozonoff, S., Pennington, B. F., & Rogers, S. J. (1991). Executive function deficits in Ozonoff, S., Pennington, B. F., & Rogers, S. J. (1991). Executive function deficits in high-functioning autistic individuals: Relationship to theory of mind. high-functioning autistic individuals: Relationship to theory of mind. Journal of Child Journal of Child Psychology and Psychiatry, 32,Psychology and Psychiatry, 32, 1081-1105. 1081-1105.

Pennington, B. F., & Ozonoff, S. (1996). Executive functions and developmental Pennington, B. F., & Ozonoff, S. (1996). Executive functions and developmental psychopathology. psychopathology. Journal of Child Psychology and Psychiatry, 37,Journal of Child Psychology and Psychiatry, 37, 51-87. 51-87.

Perner, J. (1998). The meta-intentional nature of executive functions and theory of Perner, J. (1998). The meta-intentional nature of executive functions and theory of mind. In P. Carruthers & J. Boucher (eds.). mind. In P. Carruthers & J. Boucher (eds.). Language and thought: Interdisciplinary Language and thought: Interdisciplinary themes.themes. Cambridge: Cambridge University Press. Cambridge: Cambridge University Press.

Prior, M. R., & Hoffman, W. (1990). Brief report: Neuropsychological testing of Prior, M. R., & Hoffman, W. (1990). Brief report: Neuropsychological testing of autistic children through an exploration with frontal lobe tests. autistic children through an exploration with frontal lobe tests. Journal of Autism and Journal of Autism and Developmental Disorders, 20,Developmental Disorders, 20, 581-590. 581-590.

Salmond, C. H. et al. (2003). Investigating individual differences in brain Salmond, C. H. et al. (2003). Investigating individual differences in brain abnormalities in autism. abnormalities in autism. Philosophical Transactions of the Royal Society of London, Philosophical Transactions of the Royal Society of London, B, 358,B, 358, 405-413. 405-413.

Zilbovicius, M., Garreau, B., Samson, Y., Remy, P., Barthelemy, C., Syrota, A., & Zilbovicius, M., Garreau, B., Samson, Y., Remy, P., Barthelemy, C., Syrota, A., & Lelord, G. (1995). Delayed maturation of the frontal cortex in childhood autism. Lelord, G. (1995). Delayed maturation of the frontal cortex in childhood autism. American Journal of Psychiatry, 152,American Journal of Psychiatry, 152, 248-252. 248-252.

current theoretical & practical issues in autism diagnosis dr. elizabeth sheppard developmental...

Documents

social impairments

autism diagnosis

diagnosis of autism

communication impairments

autism spectrum disorders

social communication

social non social features

mild impairments