autism spectrum disorder
Motor development problems of ASD __% dysdiadochokinesia (difficulty in rapid alternating movements) __% problems with gait or balance __% abnormal muscle tone (tightness) __% abnormal reflexes __% abnormal motor coordination (impaired finger, heel tapping, slow or shuffling gait, rigidity and tremors in arms)
- 60% dysdiadochokinesia (difficulty in rapid alternating movements) - 33% problems with gait or balance - 15% abnormal muscle tone (tightness) - 5% abnormal reflexes - 5% abnormal motor coordination (impaired finger, heel tapping, slow or shuffling gait, rigidity and tremors in arms)
Parents of autistic kids...
- Are faster on embedded figure tests (where's Waldo) - Are more likely to have systematizing fathers - Show the systematizing pattern of brain activity
Criticisms of Empathy Imbalance Hypothesis
- High comorbidity with intellectual disability, who do not experience empathy imbalance - Language development and idiosyncratic language - Face-processing deficits - Eye-tracking data and failure to cuddle
Comorbidity with intellectual disability, anxiety or phobia disorder or ADHD, social anxiety disorder, and oppositional defiant disorder.
- Intellectual disability: 70% - Anxiety or phobic disorder or ADHD: 42% - Social anxiety disorder: 29% - Oppositional defiant disorder: 28%
Environmental Risk Factors leading to ASD
- Maternal smoking in 1st trimester - Caesarian delivery (probably the conditions that made this delivery necessary rather than the delivery itself) - Baby small for gestational age (premature infant) - Older fathers - Mother exposed to pesticides or air pollution - Prenatal German measles infection (rubella) - Mother not born in Europe or North American (lower immunity to viral infections because of higher exposure via antibiotics) - Summer conception (at least in a UK sample)
Additional Brain Abnormalities in ASD - Corpus Callosum - Seizure activity - EEG abnormalities in __% - Brain volume - Head circumference - Brain connectivity
- Reduced corpus callosum size - High rate of seizure activity (33%), especially the females. - 50% have abnormalities in EEG - Volume of the brain is slightly larger, as well as the ventricle size. This occurs mostly in infancy and early childhood, and tend to be less noticeable. - Head circumference is larger - Excessive connections in frontal and prefrontal cortex and reduced connectivity with that part of the brain and the other parts.
Face and Emotion Perception of ASD
- Sort faces by physical features and not emotions (shape and colour of features) - ERP differences between familiar/unfamiliar objects, not faces in ASD individuals (mother versus stranger) - Different brain areas activated • Typicals: frontal lobes, amygdala, lateral fusiform gyrus • Autism: superior temporal gyrus
A mother given the anti-seizure medication, valproic acid, is __ times more likely to have an autistic child.
A mother given the anti-seizure medication, valproic acid, is 10 times more likely to have an autistic child.
Savant Abilities
10% of individuals with ASD Limited to very specific areas of expertise (math, music, calendar calculations) Savant abilities are much more likely to appear in the bottom third of the spectrum (lowest IQ, most debilitated)
Prevalence of ASD (DSM-5)
100/10,000
__% of individuals with ASD comorbid for at least one other disorder, __% with two or more.
70% of individuals with ASD comorbid for at least one other disorder, 40% with two or more.
Heritability coefficient of ASD
90%+
ASD is ____ times more common in ____ than _____.
ASD is 4-5 times more common in boys than girls.
Treatment for ASD
Applied Behaviour Analysis Teaching Social Skills (high functioning cases) Pharmacotherapy (tranquilizers and antidepressants)
Extreme Male Brain Theory
Autism is an extreme case of the systematizing brain, which is the route of every major symptom of autism. Explains social disability, islets of special ability, and ritualistic interests
Autism is the ____ heritable psychiatric condition.
Autism is the most heritable psychiatric condition.
Increase in prevalence of ASD
Between 1966-1993: 5/10,000 Between 1994-2004: 13/10,000
DSM Diagnostic Criteria for ASD
Deficient social interaction and communication, including deficits in: - Social-emotional reciprocity - Non-verbal communication - Developing and maintaining relationships Restricted and repetitive behaviour, including: - Movement and speech - Insistence on sameness of routines - Fixated interests - Hypo- or hyper-activity to sensory input
Theory of Mind
Deficit in understanding mental states of others, do not understand what other people are thinking or intending • States of knowledge or ignorance: difficulty understanding what other people know • Pretense, deception, lying: when we do things that are opposite or different from the things we say. Kids with autism do not do these things because they assume that people say what they mean. • Jokes, irony, sarcasm. Jokes require that we understand the mental state of the people in the joke. People with autism don't tell jokes or get sarcasm because they don't understand - think you mean exactly what you said.
ASD is associated with genetic conditions, such as...
Fragile X, PKU, congenital rubella, chromosome 15 duplication
Systematizers
Identifying, understanding rules that govern a system. Organization, structure, and rules. Males are systematizers.
Reasons for increase in prevalence of ASD
Increased awareness of the disorder Earlier diagnosis Changes in diagnostic practice (changing labels) Diagnostic substitution (to increase attention/treatment given)
Associated features of people with ASD
Intellectual and/or language impairment Motor deficits (unusual gait, clumsiness) Self-injury (head-banging) Disruptive or challenging behaviours Prone to anxiety and depression
Empathizers
Recognizing and responding to the feelings of others. Recognizing, understanding, interpreting feelings of others, receptive to social cues. Females are empathizers.
Concordance rates of ASD
Monozygotic twins: 65-75% Dizygotic twins: 3-10%
Paternal Imprinting
Paternal brain-activated genes lead to neural overgrowth, while maternal imprinted genes promote undergrowth. Paternal genes are only expressed if they comes from the father and the mother's copy is discarded.
People with ASD have excessive connections in ______________ and reduced connectivity with that part of the brain and the other parts.
People with ASD have excessive connections in frontal and prefrontal cortex and reduced connectivity with that part of the brain and the other parts.
Intense World Theory
People with ASD have too many connections in their brains, and are hyper-reactive to stimuli, creating a strong negative response to sensory stimulation (lights, sound, etc.) and symptoms arise as a way to avoid strong stimulation.
Empathy Imbalance Hypothesis
People with autism have a high emotional empathy, but low cognitive empathy. They experience what others are feeling, but cannot comprehend why, so they avoid social contact to stay away from the mysterious strong feelings.
Brain areas affected in Major deficits in Autism
Social cognition (face recognition and emotion processing): prefrontal cortex, superior temporal sulcus, mirror neurons, amygdala Language and communication: Wernicke's and Broca's areas Motor behaviour and coordination: Motor cortex, premotor cortex, cerebellum
Criticisms of Theory of Mind in Autism
Social impairment before precursors of ToM ToM & communication emerge independently ToM found in high-functioning autism ToM doesn't differentiate between ASD and intellectual disability
Heritability is...
The proportion of observed differences on a trait among individuals of a population that are due to genetic differences.
Interest in Dopamine in ASD has been sparked because of...
The role of dopamine in movement problems and dopamine-blocking agents in treatment
There is the highest male/female ratio in ______ range of cognitive function, and the lowest male/female ratio in _______ range of cognitive function.
There is the highest male/female ratio in normal range of cognitive function, and the lowest male/female ratio in very low range of cognitive function.
Specifications for ASD diagnosis: Can be with or without...
With or without intellectual impairment With or without language impairment Associated with medical, genetic, environmental condition Associated with another mental, behavioral disorder With catatonia
Serotonin in ASD
• 1/3 of ASD patients show elevated levels of serotonin in the blood • Synthesis normally down by age 5; in autism, rises to 150% of normal adult level between ages 2 and 15 years
General intellect of people with ASD
• 70%+ have mental retardation (intellectual disability) • Language, abstract reasoning problems • Visuo-spatial processing is good • Attention to detail is good • Rote memory is very good
Evidence for Empathy Imbalance Hypothesis
• Children with ASD show more facial affect in an empathy paradigm study • Adults show more muscular response in the face when shown emotional images • Children show same level of anxiety when shown pictures of distress, but often look away • High levels of personal distress to others' suffering • Eye contact with others is painful.
Cognitive versus Emotional Empathy
• Cognitive (CE) = understanding others, theory of mind • Emotional (EE) = non-cognitive process that leads us to experience the emotions we see on the faces of others
Temporal lobe and Fusiform Face Area in ASD
• Fewer cells • A lack in FFA activity during face perception
Amygdala in ASD
• Fewer cells and dendritic connections • No influence on pre-frontal cortex during face perception • Interchange between prefrontal cortex and amygdala is not damaged.
Cerebellum in ASD
• Fewer cells and dendritic connections among those cells • Abnormalities may be prenatal, part of developmental process
Pre-frontal cortex in ASD
• Fewer dendritic connections • Lower blood flow and task-related activity
Pleiotropy of ASD
• Genes confer susceptibility to other disorders • Parents: anxiety, depression, substance abuse • Same genes confer a heightened risk for other disorders as well
Applied Behaviour Analysis
• Ivor Lovaas • Shape and reward positive behaviour • Extinguish undesirable behaviours • Gold standard for treatment of autism • Psychological treatment much more effective than pharmacological treatments
Language areas in ASD
• Lower levels of interchange between Broca's and Wernicke's • Reduced activity between areas during language processing
Withdrawal to cope with the brain's chaos leads to...
• Social withdrawal = language decrement • Repetition, stereotypy = controlling chaos in a way that they can • Source of face perception problems
Variable expressivity of ASD
• Susceptible to incomplete variants of autism • Milder symptoms; atypical autism in co-twins • Social communication impairments in 20% of siblings
