HLTH 358 Week 8: Autism Spectrum

Primary features of autism

•Limitations in social communication and interaction, including: emotional reciprocity, non-verbal communication, and understanding relationships.

•Restricted or repetitive behaviors, including stereotyped movements or speech, insistence on sameness, fixations of interest, and abnormal reactivity to sensory stimuli (hyper or hypo).

* These must be long-standing, and evident across changing contexts and situations.

- easier to diagnose at younger age

=> delays in milestones

=> masking

=> easier to identify hyperfixations

Cause of autism

•Cause is unknown; but diagnosis can be made as early as 18 months, but often made between ages 5 and 8

Rates of Autism in girls vs boys

•ASD is 4x more common among boys than girls. (nb, sex differences in brain morphology, neurochemistry and maturation is becoming a very important topic, and this is one example of why its important to study!)

Heridity of autism

•ASD has a significant genetic loading (~80% concordance for identical twins vs ~30% for fraternal), and there is some evidence that the vulnerability occurs around the time of or shortly after birth.

cellular mechanisms of autism

•Autoimmune mechanisms involving the brain are a major suspect, esp over-expression of GABA (via astrocytes and microglia).

importance of avoiding Delays in diagnosis for autism

•earlier intervention is generally better for those with ASD.

Autism symptom manifestations in toddlerhood

Timeline of Autism

- modern day: reconsideration of subtypes

Brain areas assoicated with abnormalites with autism

- Brocas area

- Wernickes area

Brocas Aras (ASD)

- associated with language production

•In low function ASD, lack of language development (or backsliding) suggests some involvement here.

•But also possibly attention? Re the social aspects of interpersonal communication; this might imply involvement of the superior parietal lobule, primary visual cortex.

Wernickes area

- language comprehension

•Social meaning conveyed through gestures and facial expressions; these may include processing through Wernicke's area, but also higher cortical centres.

Causal Factors of Autism

C-sections increase risk of ASD

=> mirrored by ADHD

- OR = 1.33

Higher cortical networks associated with ASD

-

Are there meaningful subtypes of ASD

- yes

- ex. subtypes due to age diagnosis

genetic loading of autism

- found that earlier-diagnosed autism and late diagnosed autism had different sex and genetic correlations

Can ASD be prevented (or at least, treated early)

yes

- ample evidence that getting behavioural interventions can help grade school children with autism function normally

- can look into early post-natal interventions

- ex/ using an intervention to promote early child parent social reciprocity using social learnign principles