Autism: Cognitive Assessment Findings

1
Autism Cognitive Assessment Findings

• Shannon Burns
• Georgia State University
• CPS 7490

2
Diagnostic Criteria for Autism Spectrum Disorder

• The Diagnostic and Statistical Manual, fourth
  edition (DSM-IV) contains the most current
  diagnostic criteria for Autism Spectrum Disorder.
• Due to the high rate of false-positive diagnoses
  that resulted from criteria published in previous
  editions of the DSM, an extensive field trial was
  conducted involving 125 diagnosticians across 21
  sites (Freeman Cronin, 2002). The findings of
  this study resulted in the development of the
  criteria currently found in the DSM-IV, which
  include
• Impairment of social interaction.
• Qualitative impairments in communication.
• Repetitive behaviors that exhibit a restricted
  range of interest inconsistent with developmental
  expectations.
• Abnormal functioning in social communication,
  social interaction, or developmentally
  appropriate play must be evident before 3 years
  of age.

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Diagnostic Criteria for Autism Spectrum Disorder

• The criteria for diagnosing autism are entirely
  behavioral.
• One reason for this is its unknown etiology. A
  minority of autism cases have known causes, such
  as the fragile X chromosome abnormality,
  congenital rubella, tuberous sclerosis, and a
  variety of structural abnormalities of the brain,
  but none of these conditions are consistently
  correlated with autism (Rapin, 2001).
• Also, due to the extremely young ages of most
  referrals and the wide range of cognitive
  functioning which can be displayed among persons
  with autism, cognitive assessments are not
  sufficient diagnostic tools.
• Thus, diagnostic instruments are usually based on
  two main sources of information descriptions of
  the childs developmental course and behavioral
  patterns given by primary caregivers, and data
  gathered from direct observation.

4
Autism Assessment Tools

• Childhood Autism Rating Scale (CARS)
• Autism Diagnostic Interview Revised (ADI-R)
• Autism Diagnostic Observation Schedule Generic
  (ADOS-G)
• Checklist for Autism in Toddlers (CHAT)
• Screening Tool for Autism in Two-Year-Olds (STAT)
• Autism Behavior Checklist (ABC)
• E-1 and E-2 scales by Rimland
• Detection of Autism by Infant Sociability
  Interview (DAISI)
• Vineland Adaptive Behavior Scales (VABS)

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The Role of Cognitive Assessments

• Cognitive assessments should be used to
  supplement behavioral scales and developmental
  checklists.
• Autistic children have a wide range of
  intellectual competencies.
• The mean IQ of the autistic population is low,
  but at least 30 have an IQ above 70.
• Some demonstrate superior splinter skills for a
  narrow range of abilities.
• While a diagnosis of autism cannot be made based
  on cognitive functioning alone, individuals with
  autism do demonstrate a typical pattern of
  performance deficits on intelligence tests
  (Blackwell, 2001).
• They can provide standardized information about
  the overall cognitive functioning of a child, the
  presence of specific deficits, or in rare cases,
  the presence of superior splinter skills, which
  may go undetected during behavioral observation.

6
Carpentieri and Morgans (1994) Study

• Purpose To find out if autistic and nonautistic
  retarded children with the same IQs would show
  patterns of strengths and weaknesses distinctive
  from one another on the Stanford-Binet IV.
• Sample 15 autistic retarded children (mean CA
  8.72 years) and 15 nonautistic retarded children
  (mean CA 8.78 years) from local programs for
  the developmentally disabled.
• Procedure Each subject was administered the
  eight subtests designated in the SB-IV manual as
  appropriate for assessment of children
  functioning at the preschool level, and were able
  to give scoreable responses.

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Carpentieri and Morgans (1994) Study Results

• Although highly comparable in age and general
  intellectual functioning, the autistic retarded
  group and the nonautistic retarded group showed
  highly significant differences in scores that
  reflect verbal abilities.
• Autistic children scored substantially lower in
  the Verbal Reasoning area than the retarded
  children, indicating greater impairment of
  general verbal functioning.
• At the subtest level the autistic children score
  substantially lower on both Comprehension and
  Absurdities. These are the only two subtests that
  are interpreted as assessing social knowledge and
  the ability to use and relate general life
  experiences.

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Mayes and Calhoun's (2003) Study

• Purpose To understand the cognitive strengths
  and weaknesses of children with autism and
  possible effect of age and IQ on Stanford-Binet
  IV and WISC-III ability profiles and academic
  achievement.
• Sample Children referred to a child diagnostic
  clinic who met DSM-IV criteria for autism. 53
  were given the SB-IV (3 to 7 years of age, M
  4.8), and 63 were given the WISC-III (7 to 15
  years of age, M8.5).
• Procedure Children were divided into a low IQ
  group (lt80) and a high IQ group (gt80). Those
  given the SB-IV were administered the
  Developmental Test of Visual-Motor Integration
  (VMI), and those tested on the WISC-III were
  given the Wechsler Individual Achievement Test
  (WAIT). Both cognitive and achievement profiles
  were then analyzed for strengths and weaknesses,
  as well as age and IQ differences.

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Mayes and Calhoun's (2003) Study Results

• Age Effect Nonverbal IQs were greater than
  verbal IQs for young children (3-7 years of age)
  on the SB-IV for both low and high IQ groups.
  However, WISC-III verbal and nonverbal IQs were
  similar for the older group (7-15 years).
• SB-IV Profiles were similar overall for the two
  IQ groups, with high scores on Bead Memory and
  Quantitative Reasoning, indicating that young
  children with autism have strengths in visual
  skills, and rote learning, regardless of level of
  intelligence.
• WISC-III Both IQ groups scored significantly
  lower on the Comprehension subtest than on the
  Information, Similarities, and Vocabulary
  subtests, indicating a relative weakness in
  verbal comprehension and social reasoning.
• The low IQ group showed strengths in visuo-motor,
  and visuospatial skills indicated by Block Design
  and Object Assembly scores.
• The high IQ group showed significant weaknesses
  in on the Freedom from Distractibility Index
  (Digit Span and Arithmetic subtests), which is
  also characteristic of children with ADHD.

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Considerations for Assessing Autistic Children

• Gross and fine motor impairments are common among
  children with autism (Blackwell, 2001).
• Motor stereotypes are also common, such as hand
  flapping, finger mannerisms, body rocking, or
  unusual posturing.
• The severity of motor deficits is inversely
  related to IQ.
• Sensory impairments include preoccupation with
  the sensory features of an object, over or
  underresponsiveness to particular stimuli, or
  inconsistent responses to sensory stimuli
  overall.
• Attention disorders are present in nearly all
  autistic children to some degree (Rapin, 2002).
• The manifestations are variable, though. Some are
  highly distractible and hyperactive, while others
  can demonstrate long attention spans but only for
  a select few activities which they find highly
  interesting.

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Considerations for Assessing Autistic Children

• Deckner, Soraci, Blanton, and Deckner (1984)
  conducted a study with 18 severely autistic
  students in a school for psychotic children.
• Their levels of functioning were such that the
  Catelle Infant Intelligence Scale had to be
  substituted for the Stanford-Binet and many were
  so behaviorally disordered or that was impossible
  to complete their evaluations without some kind
  of modification.
• The children were intermittently reinforced with
  small bits of preferred foods for general
  compliance during testing, and as a result
  attentiveness, motivation, and consistency of
  response all increased significantly.
• As a result, the children successfully completed
  their assessments, and their scores reflected a
  more accurate measure of their cognitive
  functioning.

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Considerations for Assessing Autistic Children

• Language is delayed, distorted, or absent
  altogether in children with autism (Kanner,
  1997).
• This makes it likely that IQ scores will be
  misleading, as many subtests of cognitive
  assessments are verbal, or require a solution
  that would be enhanced by a verbal strategy
• Some preschool dysphasic autistic students who
  turn out to possess normal intelligence once they
  learn to speak, are mislabeled as mentally
  deficient when initially assessed with
  language-loaded tests.
• Nonverbal assessments, such as the Universal
  Nonverbal Intelligence Test (UNIT) can be
  effective in measuring cognitive functioning in
  autistic children without the danger of
  misdiagnosis based on speech-language
  impairments.
• See sample UNIT scores in handout.

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References

• Blackwell, J. (2001). Clinical practice
  guideline Screening and diagnosing autism.
  Journal of the American Academy of Nurse
  Practitioners, 13, 534-536.
• Carpentieri, S. C., Morgan, S. B. (1994). Brief
  report A comparison of patterns of cognitive
  functioning of autistic and nonautistic retarded
  children on the Stanford-Binet Fourth Edition.
  Journal of Autism and Developmental Disorders,
  24, 215-223.
• Deckner, C. W., Soraci, S. A., Jr., Blanton, R.
  L., Deckner, P. O. (1984). The relationships
  among two experimental and four psychometric
  assessments of abnormal children. Journal of
  Clinical Child Psychology, 13, 157-164.
• Freeman, B. J., Cronin, P. (2002). Diagnosing
  autism spectrum disorder in young children An
  update. Infants and Young Children, 14, 1-10.
• Kanner, L. (1997). Autism Part I. Harvard
  Mental Health Letter, 13, 1-4.
• Mayes, S. D., Calhoun, S. L. (2003). Analysis
  of WISC-III, Stanford-BinetIV, and academic
  achievement test scores in children with autism.
  Journal of Autism and Developmental Disorders,
  33, 329-341.
• Rapin, I. (2001). Autistic children Diagnosis
  and clinical features. Pediatrics, 87, 751-761.