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Autism Spectrum Disorders: Early Course and Diagnosis

Autism Spectrum Disorders: Early Course and Diagnosis . Rhea Paul, Ph.D., CCC-SLP And Kasia Chawarska, Ph.D. Yale University School of Medicine Child Study Center www.autism.fm. Overview. Early diagnosis of ASD: conceptual and methodological challenges First year: early signs

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Autism Spectrum Disorders: Early Course and Diagnosis

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  1. Autism Spectrum Disorders: Early Course and Diagnosis Rhea Paul, Ph.D., CCC-SLP And Kasia Chawarska, Ph.D. Yale University School of Medicine Child Study Center www.autism.fm

  2. Overview • Early diagnosis of ASD: conceptual and methodological challenges • First year: early signs • Symptoms of ASD in 2nd and 3rd year • Stability of clinical diagnosis • Changes in syndrome expression

  3. Diagnosis of Autism • Onset of Autism: prior to 36 months • Average age of diagnosis of autism in children under 12 years: 4 to 5 years • Average time elapsed between first parental concerns and the diagnosis: 2 to 3 years

  4. Onset of Parental Concerns • Average: 14.7 months (SD=6.5) • Age of first concern: • 0-11m: 20% • 12-17m: 36% • 18m-24: 44% • Primary concerns: • Speech delays • Social concerns (Chawarska, Paul, Klin et al., 2007,Journal of Autism and Developmental Disorders).

  5. Onset of Autism: Overt Manifestations • Early onset (1st year): • early manifestations of lack of social reciprocity (“inborn autistic disturbances of affective contact” Kanner, 1943) • Later onset (2nd year): • Plateau: developmental slowdown after a period of more or less typical development (Landa et al., 2007) • Regression: social withdrawal and loss of words; 20-30% (Eisenberg & Kanner, 1955; Dawson et al., 2006; Landa et al., 2007) • Large prospective studies are needed!

  6. Challenges in Early Diagnosis • Diagnostic issues: • DSM-IV (1994): few <36 month olds included in the field trial • Limited sensitivity and specificity of the state-of-the-art diagnostic instruments (ADOS-G, ADI-R) in children with mental age < 18 months • Conceptual issues: • Birth to 36 months: period of rapid development & change • Symptoms are likely to vary depending on chronological and mental age

  7. Autism in the 1st year of life • Retrospective studies: • Parental report • Video diaries analysis • Prospective studies • Recurrence risk in younger sibs: • Autism: approximately 5-10%, higher for the “spectrum” disorder • High risk for other disorders (learning problems, social difficulties, language delays, ‘broader autism phenotype’, etc.)

  8. Head Growth Pattern Infants with Autism • Unusual head growth pattern in infants with autism (Courchesne et al., 2001; 2003) • Initial acceleration, followed by deceleration after 12 months (Dawson et al., 2007 ) • Unclear etiology • Unclear relation to autism • Issues of sensitivity and specificity • Need for more precise measurement of brain size – sMRI sibling studies

  9. Abnormalities in Social Interaction • Limited social reciprocity (no social smile, few bids for attention, little pleasure derived from interactions) • Unusual eye contact • Limited affective range and facial expressions directed at others • Limited joint attention skills • Poor observational/imitative learning • Limited response to name Chawarska & Volkmar (2005). Autism in Infants and Toddlers. In: Handbook of Autism and Developmental Disorders

  10. Communication • Low frequency of communication • Paucity of conventional gestures (nonverbal communication) • Limited goals of communication (instrumental versus declarative) • Stereotypical/idiosyncratic use of language (e.g., echolalia, scripting) • Use of other’s body to communicate (hand-over-hand gestures)

  11. Abnormalities in Play and Imagination Development • Functional play (may be spared but limited) • Pretend play – marked difficulties • Absent • Present but repetitive and lacks creativity

  12. Restricted Interests and Repetitive Behaviors • Interest in specific visual stimuli (lights, spinning objects) • Seeking sensory input (jumping, rocking, spinning) • Interest in details of objects (e.g., wheels, dials) • Hand and finger mannerisms

  13. ASD Screeners-Under 3 • M-CHAT • STAT • CSBS Screener • PDDST

  14. ASD Diagnostic Instruments-Under 3 • ADOS-T • ADI-R • CARS • CSBS

  15. Best Estimate Clinical Diagnosis • Limited utility of the existing diagnostic measures (DSM-IV, ADI-R, ADOS-G) in infants and toddlers with ASD (Chawarska & Volkmar, 2005; Volkmar et al., in press) • Expert clinical diagnosis constitutes gold standard (Klin et al., 2003; Lord & Risi, 2000; Spitzer & Williams, 1988; Stone et al., 1999) • Importance of assessing social & communicative skills in a context of cognitive and adaptive functioning as well as medical hx (Chawarska et al., in press; Klin et al., 2003; Lord & Risi, 2000; Volkmar, et al., 1994). • Clinical experience matters (Rutter, 1978; Klin, Lang, Cicchetti, & Volkmar, 2000).

  16. Stability of Best Estimate Diagnosis • Short term stability (2nd year to 4 years) (Cox et al., 1999; Chawarska et al., 2007): • Very good for ASD diagnosis (80-90%) • Changes expected within spectrum due to shifts in number of symptoms and intensity • Long term stability (2 to 4 to 9 years) (Lord et al., 2006) • High stability of best estimate ASD diagnosis (90%) • Shift from PDD-NOS to Autism Dx: ~20% • Shift from Autism to PDD-NOS: ~10%

  17. Stability of the Best Estimate Diagnosis Chawarska, K. (2007) Talk presented at the Society for Research in Child Development

  18. Verbal and Nonverbal Functioning Mullen Scales of Early Learning (Mullen, 1995) NONVERBAL SCALES • Visual Reception (VR): object permanence, visual discrimination perceptual categorization • Fine Motor (FM): visual-motor coordination VERBAL SCALES • Receptive Language (RL): understanding of nonverbal and verbal communication • Expressive Language (EL): use of gestures and language to communicate

  19. Stability of Syndrome Expression • Clinical diagnosis of Autism Spectrum Disorder is relatively stable in early childhood (see also Lord, 1995; 2006; Cox et al., 1999; Charman et al., 2006; Chawarska, et al., 2007; Chawarska, 2007) • Amongst infants presenting with Autism and severe impairments in cognition approximately 30% is likely to make very significant gains in all key domains of functioning (see also Sutera et al., 2007) • Infants who present with milder symptoms are likely retain the diagnosis by the age of 3 to 4 years but worsening of symptoms is less likely

  20. Change in Socialization Symptoms: from 2 to 4 years • In the 2nd year: • Profound impairments in motivation and ability to engage in reciprocal interactions with others • In the 4th year: • Improvement in responsivity to attentional cues (response to name and verbal and nonverbal bids for attention) • Limited improvement in spontaneous initiation of social interactions Chawarska et al., 2007, JCPP

  21. Change in Communication Symptoms: from 2 to 4 years • In the 2nd year: • Profound delays in expressive and receptive language in a majority of cases • Failure to use eye contact, affect, and gestures to compensate for lack of language • In the 4th year: • improvement in responsivitiy to language and increased range of vocalizations and verbalizations • increase in frequency of communication • emergence of echolalia and stereotyped language • limited spontaneous use of language & gestures for com. Chawarska et al., 2007, JCPP

  22. Change in Stereotyped and Repetitive Behaviors Domain: from 2nd to 4th year • In the 2nd year: • Unusual interests in sensory dimensions of objects: light, texture, details • Some repetitive behaviors (lining up, grouping) • Very few motor mannerisms • Self-injurious behaviors: extremely rare • In the 4th year: • Repetitive behaviors might intensify, more frequent motor mannerisms, but overall limited increase Chawarska et al., 2007, JCPP

  23. Changes in Cognitive Functioning in Autism: from 2nd to 4th year • In the 2nd year: • Verbal skills: 30% in average to below-average range • Nonverbal skills: 75% in average to below-average range • In the 4th year: • ~50% in average to below-average range • High individual variability in the rate of progress • Verbal skills: 50% either maintained average standard scores of improved, 50% retained low scores or declined • Nonverbal skills: 45% maintained average-below average scores, 25% maintained low scores, 30% declined

  24. Conclusions • Symptoms of social dysfunction are apparent in a majority of cases by 24 months; often earlier • Stability of the Autism Spectrum diagnosis is high • Young children with ASD differ widely in syndrome expression and levels of functioning • Young children with ASD show highly variable rate of progress reflected in changes of diagnostic classification, IQ, and verbal ability

  25. Evaluating Children with ASDUnder 3 • Developmental Assessment (e.g., Mullen) • Vineland Adaptive Behavior Scales • CSBS-video example

  26. Video Examples • HL

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