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Autism - Coggle Diagram
Autism
Genetics
Relative risk (RR) - relative likelihood of diagnosis in those with siblings/cousins with diagnosis and those without any family history
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Familial risk of autism
Swedish children born 1982 - 2007
1.6m families assessed, 20,000+ had autism diagnosis
- Twins, full and half siblings and cousins with autism were identified
- Made RR graphs
- can identify likelihood based on family history
MZ twins - very high
DZ twins and full siblings - still high, but lower than MZ
Half siblings - lower, but still > than 1
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Definitions
DSM V - first category
- Persistent deficits in social communication and interactions, not developmental delays
- Deficits in 3 different areas
- social emotional reciprocity
- non-verbal communication
- developing and maintaining relationships
DSM V - second category
- Restricted, repetitive patterns of behaviour, interests or activities
- Stereotyped or repetitive speech, motor movements, or use of objects
- Excessive adherence to routines, ritualized patterns of verbal or nonverbal behavior, or excessive resistance to change
- Highly restricted, fixated interests that are abnormal in intensity or focus
- Hyper-or hypo-reactivity to sensory input or unusual interest in sensory aspects of environment
Spectrum
Refers to different area of features that might define autism
- social interactions, motor skills, language, attention, executive function and sensory processing
- spectrum refers to the presence or absence of these in different degrees
Motor differences
Compared head-lag at 6-14mo with ADOS scores at 36mo
- infants with older autistic sibling more likely to display head-lag
Drawbacks
- need large sample sizes to make conclusive statements
- lacks specificity - from this, can't say head-lag is really specific to autism
Cognitive differences
- High and low risk children
- at 9mo, 15mo did visual search
- 2yo did ADOS test
Visual search test
Infants looked at array of patterns with hidden target
- autistic children recognise hidden target easily
- enhanced visual search at 9 months predicted autism severity 2 years
- evidence for early development of cognitive systems can contribute to restricted interests
- basis for early diagnosis
Environment
Paternal age
- Swedish children - 1987 - 1992
- 883 with autism, 660 families with siblings discordant (didn't have)for autism
- meta-analysis of 12 studies from 7 countries
Results
- increased change of diagnosis at parental age of 30 and 50, plateau at 40
- persisted after controlling for other factors
C-section
- 670,000 c-section children, 31.000 has autism
- strong correlation - not cause
- Across 5 countries, c-section associated with 1.26x increased risk of autism
- not statistically significant
Diagnostic tools
ADI-R
- structured interview, 93 items, 2-3 hours
- mental age of 18 months +
- form simple sentences, express what you want etc.
- covers 3 different domains
Pros
- Provides a diagnostic algorithm for autism as described in both
the ICD (USA) and DSM
- Gives categorical results - cut-off point for diagnosis
- Specific codes - transferred to algorithm - results come quickly
Cons
- Cultural adaptation
- interpretations of questions can depend on social norms
- Administrative training
ADOS-2
- semi-structured, standardised assessment
- for children, introduce toys in set order, but child can do what they want with toys
- covers 4 main domains (language and communication, reciprocal social interaction, imagination, stereotyped behaviours)
- 5 different modules based on expressive language level and age
Pros
- structured activities - same administration everywhere
- can talk about strengths and difficulties
- many cultural adaptations
Cons
- can only take a snapshot of behaviours
- researcher needs to be very knowledgeable about typical milestones and ASD symptoms
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