Autism Spectrum Disorders: Early Course and Diagnosis

Rhea Paul, Ph.D., CCC-SLPAnd Kasia Chawarska, Ph.D.Yale University School of MedicineChild Study Centerwww.autism.fm

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

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

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

0

5

10

15

20

25

0-2 3-4 5-6 7-8 9-10 11-12 13-14 15-16 17-18 19-20 21-22 23-24

Age (monhts)

Per

cen

t

(Chawarska, Paul, Klin et al., 2007(Chawarska, Paul, Klin et al., 2007,Journal of Autism and Developmental Disorders).,Journal of Autism and Developmental Disorders).

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!

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

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.)

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

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. Chawarska & Volkmar (2005). Autism in Infants and Toddlers. In: Handbook of Autism and Developmental DisordersIn: Handbook of Autism and Developmental Disorders

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)

Abnormalities in Play and Imagination Development

Functional play (may be spared but limited)

Pretend play – marked difficulties Absent Present but repetitive and lacks

creativity

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

ASD Screeners-Under 3

M-CHAT STAT CSBS Screener PDDST

ASD Diagnostic Instruments-Under 3

ADOS-TADI-RCARSCSBS

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).

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%

Stability of the Best Estimate Diagnosis

Time 1 Dx22m (3)

14m – 26m

T1N=49

Time 2 Dx48m (8)

30m – 60m

T1N=49

%

Autism 36 Autism 25 69% (25/36)

PDD-NOS 11 31% (11/36)

PDD-NOS 13 PDD-NOS 12 92% (12/13)

BAP 1 8% (1/13)

Chawarska, K. (2007) Talk presented at the Society for Research in Child Development

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

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

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

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

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

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

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

Evaluating Children with ASDUnder 3Developmental Assessment

(e.g., Mullen)

Vineland Adaptive Behavior Scales

CSBS-video example

Video Examples HL