Autism Spectrum Disorder Flashcards
Diagnostic criteria of autism
All of the following:
- Impaired social-emotional reciprocity
- Deficits in nonverbal communicative behaviors
- Deficits in developing, maintaining, and understanding relationships
At least two of the following restricted and repetitive behaviors:
- Stereotyped or repetitive motor movements
- Insistence on sameness/inflexible adherence to routines
- Highly restricted, fixated interests
- Hyper- or hypo-reactivity to sensory input or unusual interest in sensory aspects
Consistent neuropathological findings
Brain size is often larger than average in younger subjects
1. brain size is normal or slightly small at birth, followed by a growth spurt between six and 24 months that results in larger than average brains, followed by a slowed growth that returns the brain size to average by later childhood.
2. corpus callosum is typically undersized and not enlarged proportionally to overall enlargement of the brain
3. low perfusion, though variable.
4. reduction in fiber integrity and density of metabolites as young as 6 months.
5. hyperserotonemia
6. decreased activation of glutamate + GABA
7. atypical connections with default mode network, social cognition network, and reward network.
“weak central coherence”
Neuropsychological theory that suggests people with ASD have difficulties in the integration of information from the environment into a meaningful whole. In particular, these individuals process featural and local elements of stimuli at the expense of global meaning. As a result, they have strengths in understanding and acquiring rote skills rather than those that require abstract thinking, inferences, or complex problem solving.
Male to female ratio for ASD
4:1
Comorbid conditions
ID (40–70%)
ADHD (>55%)
Anxiety disorders (22–84%)
Depression (4–58%),
Tic disorders (6%)
Seizure disorders (11–39%; more common in cases with comorbid ID)
ASD is frequently comorbid with what syndrome?
Fragile X (~50%)
Children with high-functioning autism spectrum disorder are most likely to display the most severe deficit in which of the following executive functions?
inhibition and flexibility - as is observed in individuals who perseverate in their interests and have diminished behavioral control
Imaging studies of ASD individuals have shown:
- delayed maturation of frontal lobes
- reduced activation of the amygdala during processing of facial emotion
- enlargement of lateral ventricles
Rett’s Disorder
Rare genetic disorder, primarily affects females.
Associated with MeCP2 gene
Characterized by early typical development until age 6 to 18 months, followed by sig. deterioration of motor + social skills. After period of regression, there is a plateau lasting months to years, then glow growth of skills.
Marked by:
- loss of purposeful hand movement
- replaced by repetitive hand mannerisms (e.g., “hand-wringing” or “hand-washing.”)
- progressive cerebral atrophy.
Social motivation theory to explain ASD
Individuals with ASDs have a decreased level of motivation to orient to social stimuli, which derails emergence of normal developmental pathways of social and communication skills.
Social cognitive theories to explain ASD
Impairments in the capacity to represent and reason about the thoughts, intentions, beliefs, desires, feelings, memories, and knowledge of others (poor “theory of mind”).
Poor theory of mind –> will fail to understand that the points of view or knowledge of others may differ from their own. They will, therefore, be able to predict specific concrete actions of others from their experience but will not be able to modify these predictions based on the others’ nonverbal communication cues or the social context.
Risk factors of ASD
Genetic –> High heritability rate, genes that control synaptic functioning.
Environmental –> being a younger sibling of an affected child, prematurity, advanced paternal age, and obstetric complications.
Sex ratios
Females with ASD –> lower verbal and nonverbal IQ
Male to female in moderate ID is 2:1
Diagnostic Evaluation Measures
Autism Diagnostic Interview- Revised (ADI-R) –> evaluating repetitive behaviors, stereotypes interests, rigid preferences, more valid for age over 2.
Autism Diagnostic Observation Scale (ADOS)
Modified Checklist for Autism in Toddlers (M-CHAT)
The Childhood Autism Rating Scale (CARS) –> help identify children with ASD and differentiate from developmental disabled children w/o ASD.
What are the developmental stages of Rett’s disorder?
First Stage Marked by head growth deceleration, reduced interest in play, atypical hand mannerisms, deterioration in communicative abilities, and unusual eye contact. This often follows a period of 6 to 18 months of apparently normal development.
Second Stage Marked by the presence of classic symptoms of autism, frequent and unusual motor stereotypies, loss of cognitive and language skills, and deteriorating motor abilities.
Third Stage Symptoms of ASD typically diminish, and cognitive gains are made. However, motor skills continue to decline, and seizure onset is common. Daily living skills are poor, impacted by intellectual impairment and motor disability.
Fourth Stage Motor abilities continue to deteriorate during the fourth stage of RD, and the majority of children with RD become wheelchair dependent during this time.
Neuropsychological Profile of ASD
