Pervasive Developmental Disorders (Autism Spectrum Disorders): Early Screening & Diagnostic Assessment

1. Pervasive Developmental Disorders(Autism Spectrum Disorders): Early Screening & Diagnostic Assessment Laura Grofer Klinger, Ph.D. University of Alabama Psychology Department December 6, 2004

2. Development of Screening Instruments for Early Diagnosis • The earlier the intervention, the better the outcome in terms of language development, IQ, and placement in a regular education classroom. • Increased emphasis on the development of early screening instruments that will lead to earlier intervention.

3. Why is early diagnosis important? • Most parents suspect that something is “wrong” by 18 months and seek medical assistance by 2 years. • However, most diagnoses are not made until the child is 3-4 years of age. • Earlier identification leads to earlier intervention. • At least 2 years of intervention during preschool years leads to: • Increased language development • Higher IQ • Placement in a regular education classroom.

4. Early Social Impairments in Autism

5. Early Developing Social Impairments in Autism

6. Diagnostic Process for Parents • Concerns that may be deaf or have a hearing impairment. • Concerns over their child’s lack of language development. • Concerns that they may have done something wrong as a parent (e.g., left the child during a trip, moved). • Decision to take the child in for a medical “test” to determine what is wrong.

7. Practice Parameters for the Diagnosis and Evaluation of Autism(Filipek et al., 1999) • Recommend routine developmental screening by all providers at well-child visits. • ABSOLUTE indications for immediate further evaluation (hearing test and autism screen). • No babbling by 12 months of age. • No pointing or other gestures by 12 months. • No single words by 16 months. • No 2 word spontaneous (not echolalic) phrases by 24 months. • ANY loss of ANY language or social skills at ANY age.

8. Early Screening Instruments • Checklist for Autism in Toddlers (CHAT) • Designed to screen for symptoms of autism at 18 months of age. • 9 item parent report; 5 item observation. • Developed for primary care settings. • Low sensitivity (i.e., it misses a lot of children). • Pervasive Developmental Disorders Screening Test (PDDST) • Screen for symptoms from birth to 48 months. • Brief (25-30 item) parent report checklist. • Versions for primary care and developmental clinic settings.

9. Autism Diagnostic Evaluation • There is no “medical” test for autism. • Genetic testing, referral to a neurologist recommended • Diagnosis is based on parent report and clinician observations. • Detailed Parent Interview Autism Diagnostic Interview • Structured Play Session Autism Diagnostic Observation Schedule • Behavioral Rating Scales Childhood Autism Rating Scale • Cognitive Testing • Speech and Hearing Evaluation

10. Issues in Diagnostic Assessment of Pervasive Developmental Disorder • Symptom profile changes across the lifespan. • e.g., joint attention, repetitive interests and behaviors. • Symptom presentation within the context of developmental level. • e.g., pretend play • Differentiation between the subtypes of Pervasive Developmental Disorders.

11. Diagnostic Instruments • Childhood Autism Rating Scale • Mental age greater than 36 months. • Not a lifetime diagnosis. • Developed prior to DSM-IV. • Screening instrument • Social Communication Questionnaire

12. Autism Diagnostic Interview - Revised • Mental age greater than 18 months. • 96% sensitivity, 92% specificity • Benefits: • Standardized instrument; good validity and reliability • Addresses changing symptom profile • Lifetime history • Limitations: • Influenced by parent perceptions/agendas • Over-diagnoses very delayed children. • No cutoff scores for non-autism PDDs. • Lengthy interview

13. Autism Diagnostic Observation Scale • Normed on children from 15 months through 40 years. • Four different modules. • 95% sensitivity. • Benefits: • Standardized instrument with good validity and reliability • Developmentally appropriate observations. • Limitations: • Parent interview is needed for repetitive/obsessive behaviors. • Differentiation between PDDs. • Current, not life-time diagnosis.

14. Autism vs. Mental Retardation • 40-69% of children with autism have mental retardation. • Both groups show stereotyped behaviors. • Autism is associated with an uneven pattern of skills • Autism is associated with impairments in social interaction and in nonverbal communication.

15. Developmental Disorder vs. Developmental Delay

16. Giving Feedback and Parent Reactions to the Diagnosis • Diagnosis not based on scores but on observations. • Have the parents observe part of the assessment to insure that they saw the behaviors you are discussing. • Reduce focus on IQ score. • Be sure to tell the parents that they didn’t cause the autism.