1 Autism and Autism Spectrum Disorder November 12, 2007.

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Autismand Autism Spectrum Disorder

November 12, 2007

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Definition

Complex developmental disability Impairment in:

– social reciprocity & communication– behavioral rigidity

Usually diagnosed before 30 months– some symptoms evident in infancy

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Prevalence of Autism

2-6 cases per 1,000boy:girl, 4:1No racial or socioeconomic differences

– but linked with paternal agegrowing at a rate of 10-17% / year

– but “rate” of mental retardation decreasing proportionately – better diagnosis?

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Causes

Physical symptoms:– Abnormality of brain patterning (Owens, 1999),

most often in cerebellum– Abnormal (ERP) response to auditory stimuli

(Rapin & Dunn, 2003)

Likely genetic component (Pericak-Vance, 2003) Can be caused by congenital rubella & other

neurological conditions (Lauritsen & Ewald, 2001)

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Autistic Spectrum Disorders

– Autistic Disorder

– Asperger's Disorder (hard to distinguish from high-functioning

autism)

– Childhood Disintegrative Disorder (CDD)

– Rett's Disorder

– PDD-Not Otherwise Specified (PDD-NOS)

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Characteristics of Autism

– Insistence on sameness; resists change – Difficulty in expressing needs– Repetitive, not communicative language– Little or no eye contact – Prefers to be alone– Tantrums – May not want to cuddle or be touched – Laughing, crying, showing distress for

reasons not apparent to others – Inappropriate attachments to objects– Don’t succumb to visual illusions

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The Ebbinghaus Illusion (from Frith, 2003)

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Intellectual ability

May perform above average on memory or spatial tasks

May be talented in music or drawing1/3 have IQ>70 Savants

– ten times more common in people with autism than in others with mental handicap

– occurring in approximately one in ten individuals with autism

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Language-related development

Joint attention, eye gaze– At 1st birthday, children later diagnosed with

ASD lacked: (Osterling & Dawson, 1994)

pointing & showing activity looking at faces of othersnormal response to hearing name called

Symbol use– Fail to develop symbolic play– Difficulty learning verbal labels for concepts– Trouble with waving & pointing

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Language-Related Development Theory of Mind:

– Understanding intentions and

mental states of others Impairments

– don’t produce/understand mental state words (Tager-Flusberg, 1992, Baron-Cohen et al., 1994)

– fail to make accidental-intentional distinction (Phillips, 1993)

– unable to deceive (Baron-Cohen, 1992)

– don’t understand intentionally non-literal statements (Happé, 1994)

– Causes impairment in vocabulary development!

don’t follow speaker’s eye gaze when hear new word – scan own visual field

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Language development

Delayed & deviantDon’t engage in prelinguistic conversationOnly half of autistic population develops

expressive language at all (Bailey, Phillips, & Rutter, 1996)

– Language success closely associated with IQNarrow range of grammatical

constructions – little use of questions, mental state verbs

Impaired in nonsense word repetition

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Language development

Echolalia– immediate vs. delayed– often “mitigated” – not exact, with minor

changes in structure– indicates difficulty in comprehension

Pronominal reversal – e.g. 'do you want a drink' instead of ‘I want a

drink'Use of '-ing'

– 'daddy piping', 'boy bubbling' (boy blowing bubbles) - 9 yr old autistic girl (Wing, 1976)

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Diagnosing Autism

The NICHD lists these five behaviors that signal further evaluation is warranted:– Does not babble or coo by 12 months

– Does not gesture (point, wave, grasp) by 12 months

– Does not say single words by 16 months

– Does not say two-word phrases on his or her own by 24 months

– Has any loss of any language or social skill at any age.

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Language outcomes strongly related to the amount of speech-language intervention a child receives (Stone & Yoder, 2001)

Applied behavior analysis (ABA)– Child’s interests guide selection of targets &

activities– Effective in changing IQ, adaptive behavior, &

language– Improved communication reduced

aggressive & socially inappropriate behaviors– Most effective if administered by clinicians

(Bibby et al., 2001)

Treatment

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Prognosis

Best predictors of success in language acquisition: (Toth et al., 2006)

– 3 - 4 y.o. joint attention immediate imitation of motor movements

– 4.5 - 6 y.o.pretend playdeferred imitation of motor movements

Intervention studies show preliminary success (Kasari et al., 2004)