Lecture 32: Autism Flashcards
What is the prevalence of autism spectrum disorders?
ASD = 1%
Autism proper = .25%
How heritable is autism?
Highly heritable
Sibling recurrence risk = 20%
Heritability = 37 – 84% (75% if you go by the MZ and DZ concordance)
How heterogeneous is autism?
Very heterogeneous
“If you have seen 1 child with autism, you have seen 1 child”
100s of separate disorders
What is the triad of autism disorder?
- Communication impairment
- Restricted interest and compulsive behavior
- Social impairment
Onset by 3 y.o.
Developmental disorder so NOT acquired
What is aspergers?
- Social impairment
- Restricted interest & compulsive behavior
Can communicate well
What is the difference between autism and Asperger disorder?
Autism has 3 key traits
- Social impairment
- Restricted interests/compulsivity
- Behavioral deficit!
- Communication impairment
Asperger only has 2 out of 3 traits
- social impairment - restricted interes & compulsive behavior
What is wrong with DSM 4 subtypes?
Not predicted by biology and treatment responses
-lack external validity
-language delays NOT universal in ASD nor unique
Criteria not stable over time; not reliable between centers/clinicians
“cleaving meatloaf at the joints”
Social and communicative deficits predict one another
Asperger vs. Autism = are not completely distinct
What is PPD-NOS?
Pervasive Developmental Disorder, Not Otherwise Specified
One of 5 autism spectrum disorders
-atypical autism
Are there any drugs that treat the triad of autism?
No Cat
What is the role of environmental factors?
There are 80,000 new synthetic chemicals in last 50 years
3% of neurobehavioral disorders by direct exposure
25% via epigenetic modification
Thought to play bigger role than genes?
When does symptom expression occur?
Second year of life
What is the biggest risk factor for autism?
If your sibling has autism
What prenatal exposures are known to cause autism?
- Thalidomide
- Valproic acid
- Maternal rubella infection
What does thalidomide lead to?
Autism
Valproic acid and maternal rubella infection leads to autism too
What is the one key genetic mutation that may cause autism?
Fragile X Syndrome
Significance of Fragile X syndrome?
Symptoms look like autism
Has to do with mGluR mutations
What is mGlur? Significance?
Metabotropic glutamate receptor
Important pathway in ASD symptomatology
-either too little or too much mGluR = ASD
Leads to Fragile X syndrome
The brain size of autistic children is bigger or smaller?
Bigger
What did Schultz find using diffuse tract imaging?
There was different axonal wiring in babies with autism
-led to blunted development
What are the brain regions with LESS brain activity in ASD?
- Fusiform gyrus
- person perception
- Superior Temporal Sulcus
- facial expression perception
- Amygdala
- social arousal, attention/salience
- Superior frontal gyrus
- theory of mind
- Ventral striatum
- reward system/ADDICTION)
- Lack of synchronicity among regions
What is the fusiform gyrus? Significance?
Gyrus of temporal + occipital lobe
Is activated during person IDENTIFICATION
Decrease level of activity in autism
What is one key characteristic of autism?
Kid focuses on objects a lot more than with kids
- there is no reward for looking at other people but for objects
- not true for every autistic kid
What does heuristic mean?
Enabling a person to discover or learn something for themselves
What is the heuristic model for autism?
A model of treatment for autistic kids
Starts with SOCIAL MOTIVATION increase social perception increased social cognition
How do we diagnose young kids with autism?
Track eyes to see what person is looking at
Looking at objects OVER looking at person is diagnostic
Less reward (less dopamine) for looking at people
More reward for looking at objects
How do we treat kids with autism?
Intervene at social motivation
Example: give kids oxytocin for appropriate behavior and perception to reward interacting with other people, etc.
