lecture 9 - neuropsychology and autism Flashcards
what is autism
Autism Spectrum Disorder (ASD)
- DSM-IV (dsm 4 a book that defines many disorders) :* “Autistic disorder” was the umbrella term for multiple diagnoses
- e.g., Asperger’s disorder, childhood disintegrative disorder (CDD), pervasive developmental disorders (PDD), Rett’s syndrome
what is the updated diagnosis criteria (DSM 5)
DSM 5:
* Updated the diagnosis criteria
* Autism disorder
now labelled autism spectrum disorder
describe autism medically speaking
Autism is known as “Autism Spectrum Disorder (ASD)”
* A diagnosis with deficits
* Medical descriptions often focus on deficits and challenges associated with autism, such as difficulties in social skills, communication, and sensory processing.
describe autism socially speaking
Autism is (currently) preferred to beknown as “Autism” or “Autism Spectrum”
- Social models of disability highlight the importance of accommodating diverse needs and promoting inclusion rather than focusing solely on medical diagnoses.
- Neurodiversity perspective views autism as a natural variation of human neurology rather than solely as a disorder or deficit
what is autism categorised as in DSM 5
DSM 5 – Diagnostic and Statistical Manual of Mental Disorders, 5th Edition (2013)
- Autism categorized as a neurodevelopmental disorder because symptoms are present in childhood
- Even if diagnosis only occurs in adulthood
what is the general criteria for ASD - DSM 5
Criteria A – deficits in social communication (must have at least 3 deficits in this area)
* Criteria B – repetitive, restrictive behaviours or interests (at least 2 deficits in this area)
* Criteria C – symptoms present during childhood
* Criteria D – symptoms cause impairment in regular functioning
* Criteria E – symptoms can’t be better explained by another diagnosis
- Assessing autism needs to be comprehensive and multidisciplinary.
- Assessing autism usually takes time
what is autism like across the lifespan
-is it stable?
-what symptoms of autism vary through life
Unlike ADHD, autism behaviours considered stable across lifespan (i.e., symptoms persist from childhood to adulthood).
Some variability in symptom persistence in recently literature:
* Social communication deficits
* Persist from adolescence to adulthood (Seltzer et al., 2004)
* Possible reduction in later adulthood (Howlin et al., 2013)
- Restrictive behaviours and interests
- Restrictive behaviours less frequent and less severe as individuals age (Esbensen etal., 2009)
- Rigidity and insistence on sameness doesn’t change in adulthood (Zohar & Dahan,2016
-how can autism be assessed in children
-who can asses autism
-usually includes medical assessments of associated conditions
-testing might include
-EEG use
-vision tests
-hearing tests
-genetic testing
-allows us to rule out alternate possible diagnoses
Can include a team of trained clinicians:
* Speech and language pathologist,
* occupational therapist
* behavioural therapist
* psychologist
* special education teaching
* early childhood educators
assessing autism in children
-how is vision tested
vision testing
-done using the snellen letters of allen pictures
-test there’s no other vision issue causing the symptoms (rule out)
assessing autism in children
-how is hearing tested in verbal and non verbal children
Hearing testing:
- Verbal children: regular hearing test using tones of various frequencies
- Non-verbal children: Auditory Brainstem Response (ABR
to check the child can actually hear, and symptoms are due to deficit hearing
what assessments are included in testing autism (after medical exams are complete and other diagnoses ruled out)
-what is diagnosis based on
Assessment includes:
* Interviews with parents / other important adults
* e.g., ADOS questionnaire for parents
- Standardized tests
- e.g., IQ testing, executive function tests
- Behavioural observations
- e.g., home visits, observations of play in children
diagnosis is based on behaviour
can MRIs diagnose autism
Brain imaging (e.g., MRI, CT, EEG) cannot be used to diagnose autism.
* No gross anatomical differences between autism vs non-autism
* i.e., doctors can’t “spot” autism using brain imaging
when researchers detect differences between autism vs non autism populations in mri studies, it is related to:
Functional differences
* E.g., What part of the brain is recruited to do a particular task
* Micro-structural differences
* E.g., Brain wiring, cortical thickness in micro-millimetres
can clinicians spot anatomical abnormalities in MRIs
Trained clinicians can sometimes spot large anatomical abnormalities in diseases, disorders, and illnesses
-example of gross anatomical issues : eg tumours
theories of autism
-deficits of theory of mind in autism
:Early theory suggest deficits in perspective-taking in children with autism (Baron-Cohen, Leslie & Frith, 1985)
* 80% of children diagnosed with autism fail the Sally-Ann task of ToM
* Replicated with other ToM tasks
-deficits of executive functioning in autism
Difficulties with planning and task shifting
not really supported anymore
criticisms of cognitive theories
Theory of Mind tasks might explain social communication deficits but not repetitive behaviours (a main criteria of autism behaviour)
* Some children with autism perform well on False-Belief tasks
* Children with autism perform more poorly on some EF tasks but not all!
theories of autism based on brain imaging studies
hyper connectivity hypothesis
-Posits that autism behaviours are related to an over-connection between brain areas
Default Mode Network hypo-connectivity hypothesis
DMN a major network related to social cognitive processing
* There is a biological difference in the functioning of the DMN in children with autism (under connected in children with autism)
what is brain connectivity
-why do we care about brain connectivity
-brain connectivity - the connections between multiple brain regions
-we care because brain regions work together to perform cognitive functions
-brain connectivity can tell us how the brain functions
hyper connectivity hypothesis - what does it suggest to us
Hyperconnectivity hypothesis of autism suggests that individuals with autism have much higher connectivity (hyperconnectivity) across the brain (Supekar et al., 2013)
There is too much cross-talk between brain regions (i.e., hyperstimulation of the brain)- activating too many brain regions just to do a simple task
- Sheds light on the sensory symptoms of autism
what is the default mode network
- a brain network involved in cognitive abilities and emotion regulation
when is the default mode network active
-active during
self referential processing
Processing social information relative to oneself
* Processing self-related versus other-related judgments
* Social-cognitive functions
ToM
* Inferring the perspectives, beliefs, intentions, and emotions, of others
* False-belief tasks
dmn underonnected in children with autism
development of the DMN paralells……
as the DMN matures , ______ and ______ abilities improve
Development of the DMN parallels development of cognitive and social abilities
- As the DMN matures, social and cognitive abilities improve
Since children with autism demonstrate differences in social and cognitive processes ,does the DMN function differently too?
experiment and findings
yes
-experiment done by yerys et al 2015
-question : is the DMN connectivity different in children with autism
method: Compared DMN connectivity in autism vs non-autism children
* Evaluated severity of autism symptoms
* Children ages: 8-13 years
findings
Findings:
* Children with autism had lower connectivity of the DMN compared to non- autism
* Negative correlation: higher autism symptoms = lower connectivity
default mode network hypoconnectivity
conclusions
The biological function of the Default Mode Network is different in children with autism
* There is less communication between brain regions of the Default Mode Network
* Might shed light on the social-cognitive behaviours of autism
emerging theories?
-double empathy theory
Milton (2012)
*based on Social communication involves multiple parties
* Challenges in social communication between two individuals is a mutual problem
(so not just the autistic individual cant communicate with person 1 its that person 1 also cant communicate with the autistic individual)
- i.e., double problem with empathy
- Could include interactions between:
- Autistic and non-autistic individuals
- Autistic individuals
