autism Flashcards
Kanner
- first published a description of children that he believed suffered from “autistic disturbances of affective contact”
– Observations based on 11 (also see 1971 follow up) - Treated people like objects
- Showed characteristic patterns of speech and language use
- Displayed immediate and delayed echolalia
– Reversal of pronoun use (you for I) - repetition of what you have just heard
- Obsessive insistence on sameness
- Lack of spontaneity and imagination
- Excellent rote memory
- ability to memorize things
Kanner’s infantile autism
- no dysmorphic signs, thought to be ‘normally intelligent’
- unusual parental personality traits (but no cause-effect relationship drawn)
– “Aloneness from the beginning of life makes it difficult to attribute the whole picture to the manner of early parent child relationship” - noticed that children were in their own world from a very early age; likely that parent is not responsible for that
Hans Asperger: The autism spectrum
- One year after Kanner’s publication Hans Asperger (a physician from Vienna) published his paper on “autistic psycopathy”
- Observations
– Circumscribed interests
– Motor delays
Early theory: Refrigerator mothers
- Leo Kanner suspected a lack of parental warmth and attachment to their autistic children
- Bruno Bettleheim (The Empty Fortress: Infantile Autism and the Birth of the Self)
– Mothers were causing autism in their child because of their cold and rejecting parenting likened it to being in “a concentration camp” - mothers causing autism was widely accepted bc Bettleheim would go on tv and promote this view
Bernard Rimland
refrigerator mothers
a psychologist with a son with autism (Infantile Autism: The Syndrome and its Implications for a Neural Theory of Behavior), attacked the “Refrigerator Mother” hypothesis and suggested that there was a biological basis for the condition
Epidemiology
- Occurs in approximately 1 out of every 40 births (US CDC, November, 2018 )
- More common than CP, cystic fibrosis and Down syndrome
– Approximately 50,000 children (under the age of 20) in Canada has an ASD
– 4 males for every female - Recent meta-analysis suggest it’s more like a 3:1 ratio
- fewer girls detected bc seen as a male dominated disorder
- No association with socio-economic class, ethnic origin
- No evidence of variation between countries
- No evidence of actual increase in prevalence
- No evidence that due to vaccines or any other medical intervention
Familial-hereditary genetic
- May be expressed differently in boys and girls
- There may be different genetic contributions that lead to different forms of autism (polygenic)
- Environmental factors affect the expression of autism
- Autism 2-4% and ASD 10-20% risk in sibling of children with autism–50 times the population base risk
- Concordance rates MZ-92% and DZ 10%
prevalence
- Apparent increase in prevalence due to:
– Improved awareness of the whole spectrum
– Improved diagnostic systems
– Motivation to diagnose -linked to funding and services
Age of onset in ASD
- Parents’ retrospective reports
– 30-50% by 12 months
–About 80% by 24 months
– <10% after 36 months
Diagnosis
- Autism first included in the Diagnostic and Statistical Manual of Mental Disorders in 1980 DSM-III
- Several revisions later DSM-5 it is now considered a spectrum disorder –ASD
– Encompasses previous subtypes of autism, Asperger’s syndrome and pervasive developmental disorder
DSM-5 Criteria for ASD
- Impairments in social-communication
- pragmatic of language- know how to use language to get certain things
- Restricted, repetitive and stereotyped
patterns of behaviour and interest - like predictability; can often have motor movements
- Onset during the developmental period
- has to happen within childhood period; can be diagnosed in adulthood but won’t suddenly develop in adulthood
- Symptoms must be present in the early developmental period but may manifest later
- Symptoms cause clinically significant impairment in social occupational or other important aspect of current functioning
Persistent deficits in social communication and interaction
– Deficits in nonverbal communicative behaviours used for social interaction
– Deficits in developing, maintaining and understanding relationships
– Deficits in social-emotional reciprocity
- picking up on social emotional cues
- actually taking in what people are saying
Restrictive, repetitive patterns of behaviour, interests or activities
– Stereotyped, repetitive motor movements (use of objects or speech)
– Highly restricted interests that are abnormal in intensity or focus
- spend so much time on those interests that there’s no time for anything else
– Insistence on sameness, inflexible adherence to routines
– Hyper or hyporeactivity to sensory input
- too reactive or under reactive
Latest genetic research suggest different types of autisms
- Recent genetic evidence suggest that it has multiple genetic causes and should be called autism spectrum disorders or autisms
– Research team at U of Toronto lead by Stephen Scherer have identified genetic mutations that have the highest probability of causing autism, and those that do not have a role
Genetic and environmental interactions in autism
Definitive etiology underlying ASD have not yet been identified, accumulated evidence has identified various factors, including environment al, genetic, and epigenetic factors
environmental & prenatal factors
- viral infection
- parental age
- zinc defficiency
- abnormal fetal development
- germ cell mutation
- fetus brain development dysfunction
epigenetic factors
- DNA methylation
- histone modification
- micro RNA
genetic factors
- copy number variation
- point mutation
- translocation
A common cause for autism?
- Despite the variability within the spectrum
- Researchers have focused on the similarities among persons with ASD and searched for a common cause for
– difficulties in social interaction
– Difficulties in verbal and non-verbal communication
– restricted and repetitive interests and activities
Theory of mind theory (Simon Baron-Cohen and colleagues)
– Ability to attribute independent mental states to self and others in order to predict and explain actions.
- lack understanding that other person is an individual independent of oneself
– Considered a cognitive dysfunction
- Does not account for repetitive and restricted interests
- Although theory of mind is delayed it is not absent
Theory of autism: The extreme male brain
(Simon Baron-Cohen and colleagues)
- People with autism excel with understanding objects but do poorly with understanding people
- Systematizers
– Autism better than typical males - figuring out how systems work/how objects function
- Empathizers
– Typical females better than typical males - understanding what people are feeling
Problem with extreme male theory
- Not all people with autism have enhanced perceptual functioning
- only a small subset have this
- No conclusive evidence of a connection between superior perception and poor social competence in autistic children
- doesn’t explain repetitive behaviour
- not always accurate
- Cognition alone or ‘pure logic’ does not explain how humans interpret social-emotional cues
- Does not explain repetitive behaviours and restricted interests
Theory of autism: Enhanced Perceptual Functioning (EPF) Laurent Mottron & colleagues
- There are enhanced low level sensory abilities in people with autism
- Superior visual and auditory processing (e.g., visual spatial and perfect pitch)
- Attention to detail (local perception)
- Overfunctioning of brain areas responsible for primary perceptual processing overwhelms higher level cortical areas
Theory of autism: Social Motivation Hypothesis (Geraldine Dawson and colleagues)
- “an early and extreme lack of motivation toward social information, leading to the development of a social-specific reward deficit”
- most children motivated/rewarded by social interaction but autistic children are not
- Learning from social opportunities are diminished further magnifying the difference
- Concurrently non-social interests and skill areas are being developed usually in silos
Social-motivation theory of autism
less time spent attending to faces and other social stimuli in ASD would lead to a developmental cascade resulting in decreased social competence over time
Prospective studies of siblings of autistic children
- Prospective studies show us how ASD symptoms emerge over time before there is a diagnosis of ASD
- Lack of shared eye contact, smiling and communicative babbling not present at 6 months but gradually emerges during the latter part of the first year of life in infants later diagnosed with autism
- gradual decrease of eye contact, etc.
Focused interests (FI) and the brain reward circuitry
- If not faces then what is capturing attention?
– Objects of FI have high attentional salience - girls can be very intensely captivated by people and social interaction
– Different reward processing in autism, particularly in response to social stimuli - decreased activation in the nucleus accumbens in response to monetary rewards but not FIs in autistic adults
– Over time attention to certain non-social stimuli could be systematically reinforced by an atypical reward system and may lead to the development of RI
Summary: Theories of autism
- Thus far, no one theory has satisfactorily accounted for all features of ASD
- Repetitive and restricted interests have proven to be particularly difficult to reconcile
- Heterogeneity in ASD makes it difficult to find one cause, likely there are multiple types and causes
A developmental account of autism
- Genetic, biological, neurological processes that prime children for learning within their social context in autistic children affects their ability to engage in learning to the same extent as nonautistic
– Developmental perspective
* Lower social competence in these children is a result of
– Different attentional and perceptual attunement and possibly reward circuitry to their environment coupled with a lack of experience/skill development (compounded over time) in a variety of relational contexts
- Parent-child, peer relations, community
- not necessarily a social disorder; brain is learning based on experiences
