Autism Spectrum Disorders and Severe/profound Intellectual disabilities: Differential Diagnosis - PowerPoint PPT Presentation

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Autism Spectrum Disorders and Severe/profound Intellectual disabilities: Differential Diagnosis


Autism Spectrum Disorders and Severe/profound Intellectual disabilities: Differential Diagnosis Regional Autism Team: Cork/Kerry May 2014 – PowerPoint PPT presentation

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Title: Autism Spectrum Disorders and Severe/profound Intellectual disabilities: Differential Diagnosis

Autism Spectrum Disorders and Severe/profound
Intellectual disabilities Differential
  • Regional Autism Team Cork/Kerry
  • May 2014

Session plan
  • Following this session I will know more about
  • Prevalence of ASD within Severe/Profound ID
  • Genetic syndromes and ASD
  • Best practise in identification and assessment of
    ASD in individual with ID and genetic syndromes.

  • Recommended reading
  • The assessment and presentation of Autism
    Spectrum Disorder and associated characteristics
    in individuals with severe intellectual
    disability and genetic syndromes
  • J.Moss, P. Howlin and C. Oliver. (2011)

Severe/profound ID Autism Spectrum disorder
  • ASD occurs in up to 40 of individuals with
    severe-profound ID levels (La Malfa et al, 2004)
  • ASD is more prevalent in individuals with ID
  • There is a strong, positive correlation between
    severity of ASD and severity of ID.

Severe/Profound ID without ASD
  • Stereotyped behaviours reported in 67
    individuals with ID (Berkson Davenport, 1962)
  • Compulsive behaviours reported in 40 (Bodfish
    et al, 199)
  • Large proportion fail to develop communication
  • Do not tend to develop non-verbal communication
    to accommodate

Reason for the association of ASD and ID?
  • The strength of the association has led some
    researcher to believe that there is a shared
    genetic and neurobiological pathway for ASD and
    ID (Abrahams and Gerschwind, 2008)
  • Skuse (2008) presence of an ID simply increases
    the risk that ASD will be revealed lower general
    intelligence reduces possibility for cognitive
    compensation for independently determined ASD

Why is a diagnosis important?
  • Essential to ensure that individuals receive
    appropriate support and education.
  • Behavioural management strategies, educational
    programmes and therapeutic intervention that are
    effective for people with ASD and those without
    may be very different.
  • How behaviours are perceived by professional and
    parents/carers (e.g. stubbornness in DS)

Severe ID Genetic Conditions
  • Distinguishing between ASD and the impairments
    and behaviours associated with severe ID becomes
    more difficult in individuals with genetic
    syndromes associated with ID.
  • These individual often present with a range of
    complex cognitive, communicative, behavioural,
    emotional and physical difficulties that may mask
    or emulate aspects of ASD or give rise to an
    atypical presentations of the triad of

Genetic syndromes, ASD and ID
  • Identification of ASD in a growing number of
    genetic syndromes- Down Syndrome, Angelman,
    Fragile X, Tuberous Sclerosis

Increase our understanding of genetic/biological
pathways of ASD? OR Reflect
the associated ID and other complex cognitive and
language impairments associated with particular
Particular Syndromes
  • Information on ASD in Fragile X, Down Syndrome,
    Rett's etc are available
  • in handouts here today,
  • on the Regional website (Regionalasdteam.wordpress
  • or in the Regional Team Drop box.

  • A number of genetic syndrome reported to show an
    association with ASD is ever growing.
  • important to conduct a detailed and fine grained
    assessment of ASD in genetic syndromes- e.g.
    Fragile X, Retts, Cornelia de Lange
  • Initial descriptions at a superficial behavioural
    level suggested a significant, even casual,
    relationship with ASD. However, further detailed
    investigation of phenomenology of ASD
    characteristics within their groups reveal a very
    different developmental, behavioural and
    cognitive profile to those found with idiopathic

  • It is helpful to think of these differences as
    unique and syndrome specific signatures of ASD
  • The fact that the phenomenology of ASD appears to
    differ across genetic syndromes has particular
    implications for the debate regarding the
    boundaries of ASD where do these unusual or
    atypical profiles of ASD sit within the spectrum
    of ASD characteristics?

  • Syndrome specific characterises such as hand
    flapping or excessive sociability in Angelman
    syndrome can be easily misidentified in ASD

In conclusion!
  • Need to be EXTEREMLY cautious when assessing
    syndrome groups associated with severe and
    profound ID, as ASD specific assessments and
    indeed diagnostic criteria may not be sensitive
    enough to distinguish between ASD related
    characterises and the effects of the profound ID

Identification and assessment of ASD in
individuals with severe/profound ID and/or
genetic syndromes
Difficulties in Assessment
  • Significant overlap in the phenomenology of ASD
    and presentation of severe/profound ID
  • Both populations have delayed development in
    communication, presence of repetitive behaviours
    and lack of imaginative play skills in addition
    to impairments of social interaction.

  • Some individuals with severe/profound ID may
    appear to fulfil the criteria of the ICD-10 for
    ASD, purely because they have not yet reached the
    developmental level required to acquire these
    behaviours. This is not taken into account in
    current criteria.
  • Difficult to identify one single assessment tool
    that is suitable for assessing ASD across the
    whole range of ability and ages in a single

What may differentiate ASD from ID alone?
  • It has been suggested that some specific forms of
    non-verbal communication are relatively
    unaffected in individual with ID
  • Lord and Paul (1997) Individuals with ID show
    significantly more appropriate eye gaze and
    facial expression
  • Lord and Pickles (1996) Children with ASD
    develop fewer words and are less likely to
    develop phrase speech than individuals with ID.

What may differentiate ASD from ID alone?
  • Jordon 92001) suggests impairments in
    communication in ID are likely caused primarily
    in acquisition of spoken language. Once
    effective, alternative means of communication are
    introduced, individuals are often able to use
    this alternative mode for a number of functions
    (social and needs) and across settings.
  • i.e. they have the motivation to communicate

Suitable Interview measures individuals with ID
  • ADI-R reported agreement of ADI-R and ADOS is
    lower than reported by authors in individuals
    with ID. Ability of the ADI-R to discriminate ASD
    and Severe ID is somewhat limited (Bildt et al,
    2004, Cray 2008)

Questionnaire measures for individuals with ID
  • Social Communication Questionnaire SCQ (Rutter
    et al, 2003)
  • Two forms lifetime and current version.
  • Discriminate ability of the SCQ is high in
    differentiating ASD from non-autism conditions
    and similarly good for differentiating between
    autism and intellectual disability.
  • Validation of SCQ with younger children has
    yielded inconsistent findings.
  • Nonverbal individuals are not able to score on 7
    of 39 items. (18). Not suitable for certain
    syndromes (e.g. Angelman)
  • Meant as a screening tool

Observational measures
  • ADOS suitable for a range of ages, abilities,
    developmental levels and language skills.
  • There has been some concern regarding the
    discriminative ability of the ADOS in children
    with severe ID, the diagnostic validity has been
    reported to be good across a range of ability
    levels (de Bildt et al, 2004).
  • The observational nature of the ADOS assessment
    allows for a detailed picture of autistic
    phenomenology provides an opportunity to
    identify some of the subtle behavioural
    characteristics of ASD, enabling better
    differentiation of autistic phenomenology from
    global intellectual disability

  • Recommendation from Moss et al (2011)
  • given that the focus of the ADOS is on current
    behaviour it is suggested by the authors that
    this assessment should not be used without an
    accompanying diagnostic interview or screening
    tool to aid diagnosis and clinical judgement

Combined measures
  • Childhood Autism Rating Scale (CARS)
  • Schopler et al, 1988.
  • Assess the severity of symptoms associated with
    ASD using a short parent/carer interview and
  • Main disadvantage is that it does not take
    developmental level into account when scoring.
  • It is based on the DSM-III criteria it does not
    include items referring to peer relationships,
    joint attention or symbolic play which may be
    important for early diagnosis.

  • Studies have shown that the CARS may be likely to
    misdiagnose young children with ID who DO NOT
    have an ASD.
  • Lord (1995) found that the CARS is not sensitive
    enough to diagnose ASD correctly until children
    reach 3 years of age and others report that
    scores on the CARS demonstrate a strong, negative
    correlation with level of IQ and adaptive level
    (Perry et. al, 2005) Therefore it may not be
    suitable for assessing ASD in young children or
    individuals with ID.

In conclusion!
  • Remember standardised assessments are designed to
    AID clinical diagnosis of ASD and they are no
  • Use a combination of assessment in addition to
    expert clinical judgement in order to accurately
    identify ASD
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