autism spectrum disorder Flashcards
what is an autism disorder?
a lifelong condition affecting 1% of the population
autism, increase in prevalence:
heightened awareness
broadening of the diagnostic criteria
biological factors (premature birth)
DSM 5 key diagnostic criteria
persistent deficits in social communication and social interaction
restricted, repetitive patterns of behaviour, interests, or activities
DSM 5 in addition:
symptoms must present in the early developmental period
symptoms cause clinically significant impairment in social, occupational, other important areas of current functioning
these disturbances are not better explained by intellectual disability or global development delay
changes in DSM 5
combined the previously different conditions (aspergers, pervasive developmental disorder)
now all pooled together under ASD
spectrum condition
it affects people differently and to varying degrees
range of different attributes, any of which may, or may not, occur in any one individual to a greater or lesser extent
main characteristics
social impairment
communication impairment
restricted, repetitive patterns of behaviour, interests or activities
what is usually the first symptom of autism identified?
social impairment
social impairment in toddlers with autism
usually do not want to be picked up and my arch their backs when picked up
social impairment difficulties
can have difficulty entering social relationships and predicting others behaviour, or understanding motivations
communication impairment
general consensus that language is commonly impaired or absent in people with autism
why do autistic people tend to use communication?
for instrumental rather than social purposes
what do autistic people tend to struggle to discriminate between?
literal meaning vs sarcasm
non verbal communication impairments
struggle to comprehend and use facial expressions
what does content of communication tend to be?
repetitive and egocentric
4 types of restricted, repetitive patterns of behaviour, interests or activities
a) stereotyped or repetitive motor movements, use of objects, or speech
b) insistence on sameness, inflexible adherence to routines, ritualised patterns of verbal or non verbal behaviour
c) highly restricted, fixated interests that are abnormal in intensity or focus
d) hyper or hypo reactivity to sensory input or unusual interests in sensory aspects of the environment
Asperger’s syndrome
considered part of the spectrum by many, others see it as a special sub group or distinct condition
no delay in language development
symptoms shown in Asperger’s syndrome
social interaction difficulties
repetitive or stereotypes behaviours
obsessional interests in narrow subjects
theory of mind
the ability to put oneself into someone else’s shoes, to imagine their thoughts and feelings
mindreading and mentalisation
what does theory of mind allow us to do
make sense of another persons behaviour
can imagine a whole set of mental sets and predict what they might do next
sally and ann task
false belief task (ToM task)
attributing false belief: to recognise that other people can have divergent or untrue beliefs about the world
sally and ann task results
85% neurotypical children
86% down syndrome children
20% children with autism
mindblindness theory
children with ASD are delayed in the development of their theory of mind, leaving them with degrees of mindblindness
cannot explain all non-social characteristics in autism
what symptoms of ASD does the mindblindness theory explain
ability to attribute mental states is the basis for social interaction and communication
repetitive patterns of behaviour…. provide predictability
the extreme male brain
individuals whose systemising is above average, but who are challenged when it comes to empathy
sex differences in typically developing individuals
females perform better on empathising tests
males perform better on systemising, the drive to analyse or construct any kind of system
how much more prevalent is ASD in males than females?
4 times in autism
9 times in Asperger’s
possible causes of ASD
heritability
environmental risk factors
evidence for heritability as a cause
covert et al (2015) twin study
covert et al (2015) twin study method
twin pairs born 1994-1996 in england and wales
5 different measures with 203- 6,423 twin pairs per measure
covert et al (2015) twin study results
monozygotic twins: concordance of 77% to 99%
dizygotic twins: concordance of 22%- 65%
variance across tools but all significantly higher across assessment tools for monozygotic twins
environmental risk factors as a cause
advanced parent age
pregnancy and birth complications
pregnancies spaced less than one year apart
infection during critical periods of early in utero neurodevelopment
pregnancy birth complications
extreme prematurity
low birth weight
multiple pregnancies
3 differences in brain growth
1) appear to have slightly smaller brain at birth
2) brain undergoes abnormally quick growth in infancy
3) growth slows significantly by adolescence
brain basis of theory of mind (Castelli et al., (2002))
animations of two triangles interacting in different goal directed ways
people with ASD has difficulty describing the intentions of a triangle trying to trick/ coax the other
brain basis of ToM functional imaging results
similar cerebral blood flow in the visual association cortex
lower levels of blood flow in the superior temporal sulcus (STS) and the medial prefrontal cortex
fusiform gyrus (face area) in ASD
traditionally thought to be impaired or underdeveloped in people with autism
decreased fusiform gyrus activity repeatedly reported in ASD
what might decreased fusiform gyrus activity in ASD be a consequence of?
a developmental consequence of early dysfunction of the amygdala and thus reduced salience of facial stimuli in ASD
Shultz and colleagues (2005)
found little or no activity in the fusiform face area in people with autism when they were viewing pictures of human faces
Event related potentials (ERP) study (Apicella et al., 2013)
suggested the effect may not be due to specific impairment of the FFA but rather dysfunction of neural mechanisms and networks involved in driving and integrating the social information by faces
oxytocin
peptide that facilitates pair bonding and increases trust and closeness to others
levels of oxytocin in children with autism
lower levels
effect of administering oxytocin to individuals with ASD
increased performance in tests of emotion recognition
improved performance of adults with high-functioning ASD on a computerised ball-toss game that requires social interactions with fictitious partners
increased amygdala activity in response to facial stimuli in people with Asperger’s syndrome
