Download autism spectrum conditions

AUTISM SPECTRUM CONDITIONS
AP SAYGIN
Reading Frith 2012
Causes of Autism: Historical
• 1950s: “Refrigerator mothers” !
• Childhood szchizophrenia
• Autism diagnosis: 1980s
Pervasive Developmental Disorders
Reciprocal Social
Interaction
Communication
Restricted and
Repetitive Behaviors
Pervasive Developmental Disorders
Impairments in:
Nonverbal behaviors: eye gaze,
facial expression, body postures,
and gestures to regulate social
interaction
Peer relationships
Seeking to share enjoyment,
interests, or achievements with
other people
Social or emotional reciprocity
Delay in, or lack of development
of, spoken language
Impairment in the ability to
initiate or sustain a conversation
with others
Stereotyped and repetitive use of
language or idiosyncratic
language
Lack of varied, spontaneous
make-believe play
Motor stereotypies
Repetitive behaviors
Narrow Interests
Rituals, routines
Preoccupation with objects or
even parts of objects
Prevalence
Why the increase?
• Changes in diagnostic criteria in 1994
– New changes DSM5
• Awareness and detection
– Diagnostic tools and early detection
– Awareness: Doctors, parents, schools…
Changes in Diagnostic Criteria, 1994
• Autism a cluster of symptoms
• Spectrum idea
• May actually be different conditions that don’t
belong under the same umbrella
High rates of ASD symptoms in…
• Epilepsy, Fragile X syndrome, Partial tetrasomy
15, Down syndrome, Rett complex variants,
Williams syndrome,, Fetal alcohol syndrome,
Thalidomide embryopathy, Herpes and rubella
infection…
• May provide clues to neurobiology
Early Diagnosis
• Autism Diagnostic Interview (ADI)
– Parents are interviewed
• Autism Diagnostic Observation Schedule
(ADOS)
– Child is observed
• Based on developmental “benchmarks”
Early Diagnosis
• Research under way to develop earlier and
earlier detection
• MRI and fMRI “biomarkers”
• Increased availability of diagnostic tools might
be helping to correct previous under-diagnosis
• Or possibly leading to over-diagnosis
Media Attention
Pros and Cons
Awareness leads to
increased funding and
research
But also can cause panic
among the public re the
“autism epidemic”
On that note
• Vaccines do NOT cause autism
– More scientific rephrase: Evidence that vaccines
do not cause autism MUCH stronger than
evidence that they do
– Vaccines are pretty important!
– Unfortunately, many in the USA still believe the
false assertions about vaccines, in some places
creating epidemics of infectious diseases
What’s the story with vaccines anyway…
• Lets look at it in comic form…
• Basically, the study had 12 subjects, was unethically
conducted in the first place, was not supported by the
children’s medical records,
• Wakefield had a huge financial conflict of interest he
did not disclose
• Paper retracted, Wakefield lost his medical license
• Yet the damage goes on…
– http://www.jennymccarthybodycount.com/
– http://www.facebook.com/thinkingpersonsguidetoautism
Children with Autism
• Early signs
– Lack of eye contact
– Lack of affect
– Lack of orienting and responding to others
• Delayed at
– Smiling, responding to name
– Sitting up, pointing
– Demonstrating interest to other people
Children with Autism
• Not commonly diagnosed before 2 years of
age
– Active research pushing this earlier and earlier
(e.g., Eyler, Pierce & Courceshne, 2011 12-24
months fMRI)
• By 3 years of age, difficulties in three major
domains are typically observed
Multi-Disciplinary Assessment
Developmental History
* Psychologists, Psychiatrists, Social Workers
Cognitive/Developmental/Behavioral
* Psychologists
Diagnostic Assessment
* Psychologists, Psychiatrists
Speech, Language, & Communication
* Speech & Language Pathologists
Assessment of Sensory and Motor Skills
* Occupational Therapists, Physical Therapists
Specialized Medical Evaluations
* Neurologists, Geneticists, GI
Neuropsychological, Academic, Vocational Evaluations
*
Psychologists, Educational and Vocational Specialists
Symptom Domains
• Communication
• Social interaction
• Repetitive/Restrictive behavior
Communication
• 33-50% are non-communicative
• Delayed language
• Repeating sentences or questions addressed
to them (“parrot speech”)
• Lack of joint attention limits interactions
Social Deficits
• Less eye contact
• Difficulty in forming and maintaining
relationships
• Less turn-taking
• Less gesture with speech
• Less imaginative play
• Less answering to own name
• Impairments in theory of mind
Restrictive/Repetitive Behavior
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Compulsive behavior
Ritualistic behavior
Stereotypy
Self-injury
May be initiated by stress or pleasure
“Stimming” – self stimulation
Changes in DSM 5
• DSM-IV: Too broad. Many children categorized as
Asperger or PDD:NOS (Pervasive developmental
disorder: Not otherwise specified) may not need
services or treatment
– Can explain “autism boom”
• Social and communicative symptoms grouped together
since they correlate
• Sensory disorder added to symptoms
– Abnormal responses to sensory stimuli
– e.g., extreme sensitivity to light, sound, touch
• Early research suggests DSM5 more accurate model
than DSM-IV but may benefit from revision (4/7
instead of 5/7)
High Functioning Individuals
• Aspergers
• Temple Grandin
• Have recently expressed themselves more and
more (especially online)
• Perhaps not a disorder, just not “Neurotypical”
Other Findings
• Genetic component
– Siblings born of families with an ASD child have
heightened risk of being diagnosed
• 3%: core syndrome
• 10-20%: spectrum disorder
• Identical twins affected in 60-90%
• Opportunity to study “at risk” populations
– First-degree relatives: increased rates of affective disorders
(depression, bipolar), social phobia, obsessive-compulsive
disorders, (ADHD?, Tourette syndrome?)
– First-degree relatives: possibly increased rates of learning
disorders
Other Findings
• 2:1 to 4:1 ratio for Male:Female
• Highly increased risk of seizure disorders
• Parents
– Maternal and paternal age
– Socioeconomic status and paternal education
– Maybe a diagnostic difference
Intellectual Deficits and Strengths
• Close link between autism and mental
retardation
• Between 76% and 89% have impaired
intelligence
• Savant abilities appear in a very small
percentage (5%).
Brain differences
• Brain size/grey matter volume
Schuman et al 2010
Brain differences
• Further relative differences
– Cerebellum
– Corpus callosum
– Amygdala
– Cingulate
– Fusiform gyrus
Possible atypical face processing
Eye gaze and faces
Klin et al.,2002; Pelphrey et al., 2002
Brain Connectivity
• May be a more realistic avenue than gross
anatomy and may explain those findings
• Evidence for underconnectivity
• Links to genetics
Some theories of autism
• Currently these don’t “explain” autism and some
are more hokey than others but worth knowing
about
• Hypotheses
– Extreme male/Empathizing-Systemizing
– Broken mirror neurons
• Preferred version: “The social brain”
– Weak central coherence
– Executive dysfunction/Attention
– Theory of Mind
Empathizing/Systemizing
• Simon Baren-Cohen
• Measures a person's strength of interest in empathy
(the drive to identify a person's thoughts and feelings
and to respond to these with an appropriate emotion);
and a person's strength of interest in systems (defined
as the drive to analyse or construct a system).
• Extremely high S to E ratio ~ Autism
• High S to E ratio also ~ Males
• Fetal testosterone
• Linked to sex differences in cognition (an important
book: Delusions of Gender, C. Fine)
Mirror Neuron System
Dapretto et al.
- Social/communicative deficits ~ Broken mirror neuron system
- The evidence is not very strong and many counterexamples available
- Possibly part of autism, but not likely to explain social deficits
- The social brain: A complex network that enables us to recognize
other individuals, evaluate their mental states, interact with them.
- Not just mirror neurons (includes STS, Inferotemporal, amygdala,
orbitofrontal – Pelphrey & Carter, 2006)
Weak Central Coherence
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Characterization of processing deficits
Failure of holistic processing
Bias toward details, local
Difficulty with global, “big picture”
Poor use of language context
Executive Dysfunction
• Could explain some other behaviors such as
repetitive behaviors and inability to adapt in
conversation
• A relative lack of social attention (e.g, faces,
voices, people) ; attention to the inanimate
environment (e.g., Chawarska, Klin, &
Volkmar, 2008)
Theory of Mind
• Inability to put yourself in others’ shoes
• Not understanding people’s behavior based on
their mental states such as desire, belief and
knowledge
• Failing to understand difference in perspective
• Sally Ann and ‘false belief’ tasks
Treatment/Remediation
• Parents, occupational therapists
– Does help
• Behavior management techniques can improve self-injury,
self-stimulation, and other targeted behaviors
• No medication for majority
– Dopamine antagonists, atypical neuroleptics,
anticonvulsants, SSRIs, stimulants, lithium, high doses of
vitamins, amphetamines (and more)
• Diet
• Physical exercise
• Sensory awareness
Implications
• All people are individuals first and foremost; at
least as true in autism as in “neurotypicality”
• Respect for people on the spectrum
• Focus on managing the environment
• Foster adaptive skills
• People with autism; not “autistic”
Summary
• Autism is a complex (and changing) diagnosis
• Behavioral diagnosis
– Emerging biomarkers
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Not caused by vaccines or “refrigerator moms”
Genetic factors
Environmental factors (not known)
Neurobiology under study
– Larger brains
– Some local differences
– Connectivity differences
• Individual differences between people on the
spectrum