An Overview of Autism Spectrum Disorders

by Tony Attwood

Chapter 1

Autism … By Any Other Name

• Pervasive Developmental Disorder

• Autism Spectrum Disorder

What is Autism?

• According to the American Psychiatric Association (APA):– Severe qualitative impairment in:

• Reciprocal interaction (i.e., doesn’t have intuitive ability to socialize)

• Verbal and nonverbal communication

– Restricted range of activities and interests

Earliest Signs of Autism

• Sleep and feeding problems

• Difficult to comfort

• Not interested in people

• Fascination with sensory experiences

• Doesn’t imitate parents or seek their reassurance/approval

• Poor eye contact

Signs That Typically Lead to Evaluation by Specialists

• Communication delays (speech and gestures)

• Delays in self-care skills (e.g., toilet training)• Unusual reactions to sensory experiences• Problems with play, learning, emotion

management, and/or behavior• General developmental delay or other

medical problems

Age of Onset

• Most children with autism show signs in first 18 months

• 20%-40% have “regressive” or “late-onset” autism– develop normally for first year or two, then

lose speech, become self-absorbed

• By age 3, the two types are indistinguishable

Disorders on the Autism Spectrum

• Autistic disorder

• Rett’s disorder

• Childhood disintegrative disorder

• Pervasive developmental disorder-not otherwise specific (PDD-NOS)

• Asperger’s disorder

Autistic Disorder

• First described by Leo Kanner in 1943

• What we traditionally have referred to as “autism”

Autistic Disorder--APA Diagnostic Criteria

1. Impairment in at least two areas of social interaction:

– Markedly impaired use of nonverbal behaviors (e.g., eye contact, facial expression, gesturing)

– Failure to develop developmentally appropriate peer relationships

– Lack of spontaneous seeking to share enjoyment, interests, or achievements with others

– Lack of social or emotional reciprocity

Autistic Disorder--APA Diagnostic Criteria (cont.)

2. At least one impairment in communication:– Delay or total lack of spoken language– If child has adequate speech, marked

impairment in ability to initiate or sustain a conversation with others

– Repetitive or idiosyncratic language– Lack of varied, spontaneous make-believe play

or age-appropriate social imitative play

Autistic Disorder--APA Diagnostic Criteria (cont.)

3. At least one restricted, repetitive and stereotyped pattern of behavior, interests, or activities:

– Repetitive motor mannerisms, such as hand or finger flapping

– Inflexible adherence to specific, nonfunctional routines or rituals

– Persistent preoccupation with parts of objects– Encompassing preoccupation with one or more

restricted patterns of interest that is abnormal in intensity or focus

Rett’s Disorder

• Genetic disorder occurring primarily in girls • Initial period of normal development, then rapid

deterioration• Symptoms include

– “Hand wringing” movements and loss of functional use of hands

– Slowing of head/brain growth– High support needs for daily living– Muscle problems

• Debate as to whether this should be considered a form of autism

Childhood Disintegrative Disorder

• Rare neurological disorder• Normal development until age 3-5, followed

by rapid, severe deterioration in:– language– social interest and ability– play– self-care abilities (e.g., bladder and bowel control)– cognitive skills

• More severe than late-onset autism

Pervasive Developmental Disorder-Not Otherwise Specified (PDD-NOS)

• Vague term causes confusion

• APA differentiates from autistic disorder on basis of late onset, atypical symptoms, or sub-threshold symptoms

• Attwood’s description: “fragments of autism”

Asperger’s Disorder: History

• 1944: Austrian pediatrician Hans Asperger writes paper re: patients with “autistic personality disorder”

• 1981: British psychiatrist Lorna Wing coins term “Asperger’s Disorder” in a 1981 paper describing patients with same symptoms

• 1991: Dr. Uta Frith translates Asperger’s original paper into English

• 1994: Asperger’s Disorder added to APA diagnostic manual (DSM)

Asperger’s Description of Children with “Autistic Personality Disorder”

• Impaired conversation skills• Poor control of emotions, with tendency to

intellectualize feelings• Socially immature• Egocentric preoccupation with a specific topic or

interest that would dominate their thinking and play

• Clumsiness• Sensitivity to some sounds or smells• Poor organizational and self-help skills

Asperger’s Disorder--APA Diagnostic Criteria

• At least 2 qualitative impairments in social interaction

• At least 1 restricted repetitive and stereotyped pattern of behavior, interests, or activities

• No clinically significant general delay in language, cognitive, or self-help skills*

*criteria that distinguishes it from Autistic Disorder

APA Criteria for Asperger’s Disorder

• Subject of growing criticism

• Asperger’s original cases wouldn’t fit criteria, because of language delay

• May change in future versions of DSM

High-Functioning Autism

• Not a DSM diagnosis

• Autism without mental retardation (IQ of 70+)

• Controversy: Is it a different disorder than Asperger Syndrome?

Key Dimensions of ASD

• 5 characteristics or dimensions of autism– Social– Communication– Cognitive– Interests– Sensory

• Each has a range, or “spectrum,” of expression

Social Dimension

Aloof, avoids social interaction

Passive, tolerates social interaction

“Active but odd”

“Active but odd”, expresses interest in social interaction (especially with adults) in idiosyncratic or immature ways

Classic autism Asperger’s

Communication Dimension

No spoken language

Limited speech (may require prompts); echolalia

Significant pragmatic difficulties

Remarkable verbal fluency, but unable to recognize others’ lack of interest

Classic autism Asperger’s

Cognitive Dimension

Profound learning problems; focused on sensory qualities of objects

Unusual learning style w/ relatively advanced skills in engineering-type areas (e.g., jigsaw puzzles or technical drawing)

Average to precocious academic abilities; may have poor organizational skills

Classic autism Asperger’s

Savant Abilities

10% of children with autism develop specific “splinter skills” far beyond their overall level of development

Interests Dimension

Preoccupation with parts of objects; spinning wheels; flipping switches

Focus on collecting/hoarding objects.

Focus on acquiring and remembering facts about a specific topic

Classic autism Asperger’s

Sensory Dimension

Extreme sensitivity to smells, noises, bright lights, etc.

Lack of visible response to some sensory experiences, including pain or cold

Preoccupation with sensory experiences

Sensory Meltdown = Response to overwhelming

and unavoidable sensory experiences

Progression Along the Spectrum

• Children can progress within each of the 5 dimensions of autism

• Children with early autism/language delay can progress toward a diagnosis of Asperger Syndrome

Causes of Autism

• Autism is a neurodevelopmental disorder caused by specific parts of the brain not functioning as we would expect

• Old “refrigerator mother” theory--that autism was caused by an emotionally unavailable mother--has been clearly disproven

Genetic Links

• Autism rates:– In the general population, less than 1%– In a family that already has 1 child with

autism, odds of having another are 5%-7%– Among identical twins, if one has autism,

odds that the other will also have autism are 70%-90%

Broader Autism Phenotype

• Recent research shows that relatives of children with Asperger Syndrome display similar traits--but to a lesser degree– Suggests a genetic link

Chromosomal Abnormalities

• Specific chromosomal abnormalities--such as Fragile X syndrome--can cause a child to develop characteristics of autistic disorder

• These abnormalities are not inherited, but occur due to an error when the egg or sperm cell is developing

• Damaged “genetic blue print” affects brain development

Neurochemistry

• Neurotransmitters are chemicals that transmit signals from one brain cell to the next– Research has shown serotonin and

dopamine may be dysfunctional in autism• Meds that attempt to modify levels of these

neurotransmitters sometimes help with mood and emotion management

Neuropathology

• 10% of children with autistic disorder and 25% of children with Asperger’s disorder experience period of unusually rapid head growth– Brain may be enlarged by as much as 10%

(macrocephalus)– By later childhood, brain size within normal

range

Neuropathology (cont.)

Neuroimaging studies suggest possible abnormalities in frontal cortex and amygdala (brain’s centers for social reasoning emotional regulation)

Possible Metabolic Problems

• Phenylketonuria (“PKU”)--an enzyme deficiency that prevents the metabolism of the amino acids in meat and dairy--can cause autism-like symptoms

• Ongoing debate: Is autism caused by a problem in metabolizing gluten (in cereals) and casein (in dairy)?– Anecdotal reports, but no scientific

evidence

Do Infections Cause Autism?

• Theories (none proven)– Infections during pregnancy

• German measles (congenital rubella)• Herpes• Immigrant mothers’ immune system

– Early childhood infections• Herpes encephalitis• Post-measles encephalitis

– Measles Vaccination

Neuropsychological Learning Theories of Autism

• Delayed theory of mind

• Weak central coherence

• Impaired executive function

Lacking “Theory of Mind”

• Inability to recognize and understand others’ thoughts, beliefs, intentions

Weak Central Coherence

• Good at spotting details, but trouble seeing the “big picture”

• Classroom problems occur because child doesn’t know what to focus on

Impaired Executive Function

• Impairment in – Organizational and planning abilities– Working memory– Inhibition and impulse control– Time management and prioritizing– Using new strategies

Possible Co-morbid Disorders

• ADHD• Epilepsy (seizures)• Down syndrome• Cerebral palsy• Muscular dystrophy• Tourette syndrome• Tuberous sclerosis or neurofibromatosis

– Specific brain lesions may cause signs of autism

Secondary Disorders

• Anxiety disorders

• Mood disorders (i.e.,depression and bipolar disorder)– Higher familial rates of mood disorders

• Conduct disorders• Unclear whether these disorders are

characteristics of autism, or whether they occur due to stress and frustration

Gender and Autism

• Ratio of boys to girls– Autism: 2 to 1

– Asperger Syndrome: 5 to 1

• Is clinical picture and response to treatment different in boys vs girls?– Clinical experience suggests girls with Asperger

Syndrome are better at hiding their social confusion and respond better to programs teaching social understanding

Autism Rates

• 1966-1991, average estimated rate was 1 in 2,273

• During 1990s, average estimated rate increased to 1 in 787

• In 2007, estimated rates ranged from 1 in 1000 to 1 in 150

Is there an autism epidemic?

• Some reasons for increased rates:– Definition of autism has been broadened– Children can now be diagnosed with more

than one developmental disorder– In the past, children with intellectual

disability were not evaluated for autism– We’ve become better at recognizing

symptoms

Conclusion

• Although autism is a life-long disorder, the prognosis is much better than in the past– For many on the autism spectrum, best outcome

could include full-time job, living independently, and marrying

• No miracle cures, but intervention can greatly improve outcomes– Challenge: Huge increase in referrals without

proportional increase in resources