Intro to atypical development

Question 1

broad definition of development

Answer 1

• study of change and stability over the lifespan
• how we change physically, cognitively, behaviourally and socially
• due to biological, individual and environmental differences

Question 2

what do we need to remember about language (when describing atypical development)

Answer 2

• do not always need to be negative
• recognise them as differences not deficits
• diversity is important
• use terms like ‘condition’ and ‘difference’
• listen to ‘experts-by-experience’
• autistic people have led the change

Question 3

person first vs identity first language

Answer 3

1. person first = ‘person with autism’
2. identity first = ‘autistic person’

Question 4

what is the gold standard for testing atypical development?

Answer 4

• two control groups
  1. one matched to atypical group’s chronological age
  –> if perform worse than this group (only) there is a delay
  2. one matched to atypical group’s mental age
  –> if perform worse than both groups could be a delay or a difference

Question 5

reasons for atypical development

Answer 5

1. Pre-natal effects
   –> e.g. exposure to teratogen
   –> fetal alcohol spectrum disorder
2. Environmental effects
   –> e.g. complications during birth
   –> cerebral palsy
3. Genetic effects
   –> e.g. hereditary
   –> e.g. spontaneous mutations (like copy number variants)
4. Unknown (like multifaceted effects)
   –> Autism
   –> ADHD

Question 6

developmental conditions with a known GENETIC cause

Answer 6

• William’s Syndrome
• Down’s Syndrome
• 16p.11.2 (example of a CNV)

Question 7

developmental conditions with a known ENVIRONMENTAL cause

Answer 7

• Fetal alcohol spectrum disorder (FASD)

Question 8

developmental conditions with UNKNOWN causes (probably multifaceted)

Answer 8

• Autism spectrum conditions
• ADHD
• Intellectual disability

Question 9

basic genetics

Answer 9

• every cell has DNA
• DNA has instructions for how to build proteins
• basis for our development
• structure and function of the body is governed by the types and amounts of proteins the body synthesizes
• DNA is packaged into genes and humans have approx. 21,000 TYPES of genes
• genes are contained in chromosomes (each chromosome contains 100s to 1000s of genes)

Question 10

very basic map of genes

Answer 10

DNA –> genes –> chromosome –> cell

Question 11

how do we label parts of the chromosome?

Answer 11

1. chromosome arm = each chromosome has a short arm (p for petite) and a long arm (q)
2. chromosome region = regions are labelled with numbers
   –> lower numbers are those closest to the centre

Question 12

chromosomal abnormalities that can lead to atypical development

Answer 12

• genetic abnormalities can occur when there are too many or too few occurrences of particular genes
  –> can have an extra chromosome (e.g. Down’s Syndrome have an extra 21 chromosome)
  –> other people can have parts of their chromosomes duplicated or deleted

Question 13

brief examples of atypical conditions due to genetic abnormalities

Answer 13

1. Down’s Syndrome = extra chromosome
2. 16p.11.2 = duplication of a certain part of a chromosome
3. William’s Syndrome = deletion of a part of a chromosome

Question 14

what is 16p.11.2?

Answer 14

• depletions and duplications of 16p.11.2 have come under scrutiny due to their association with a range of developmental conditions:
  –> ADHD
  –> Autism
  –> Anxiety
  –> OCD
• can have more (duplication) or less (deletion) of certain genes

Question 15

different variations of 16p.11.2 presentation

Answer 15

• leads to developmental delay, autism or intellectual delay in some
• on others it remains undetected due to no physical or developmental symptoms
• generally only detected when children come to clinic with signs of developmental delay and autistic features
  –> can be very very hard to detect

Question 16

duplications vs deletion of 16p.11.2

Answer 16

• have similar links to autism, ADHD and intellectual disability
• also have their differences
  –> deletion = obesity and larger heads
  –> duplication = schizophrenia and bipolar disorder

Question 17

overview of William’s Syndrome

Answer 17

• caused by spontaneous deletion at chromosome 7q11.2
• always a deletion
• very specific cause every time (same deletion at same arm and region)
• characterized by:
  –> distinct facial appearance
  –> cardiac anomalies
  –> highly sociable personality
  –> atypical cognitive profile
  –> connective tissue abnormalities
• very rare (approx. 1 in 10,000)

Question 18

cognitive profile of William’s Syndrome

Answer 18

• can do IQ tests and other cognitive tasks to test them
• need to remember individual differences exist
• tend to have very good language abilities
  –> great verbal, descriptive and conversational ability
• struggle in their visuospatial IQ/ability
  –> e.g. can describe an elephant perfectly but struggle to draw an elephant and represent it visually

Question 19

what causes Down’s Syndrome?

Answer 19

• always a duplication
• always a duplication of chromosome 21
• doesn’t have to be a full duplication
  –> doesn’t have to be a perfect replication
  –> can be partial

Question 20

physical characteristics of Down’s Syndrome

Answer 20

• individual differences
• but some common traits:
  –> Decreased or poor muscle tone
  –> Shorter neck
  –> Flattened facial profile and nose
  –> Upward slanting eyes
  –> Wide, short hands with short fingers
  –> A single, deep, crease across the palm of the hand

Question 21

cognitive
characteristics of Down’s Syndrome

Answer 21

• individual differences
• some common causes:
  –> Short attention span
  –> Impulsive behavior
  –> Slow learning
  –> Delayed language and speech development
  –> Variable IQ (average between 30 -70, neurotypical tends to over 100)

Question 22

mechanisms of fetal alcohol spectrum disorder

Answer 22

• alcohol is a teratogen
• ethanol is thought to alter DNA and protein synthesis
  –> also inhibits cell migration which leads to physical and cognitive changes
• no clear on the amount of alcohol needed to lead to FASD
  –> can depend on when the alcohol is consumed
  –> binge drinking leads to more severe symptoms
• more prevalent than what we think
  –> once reached 2-3% prevalence in Canada

Question 23

what is a teratogen?

Answer 23

agent that causes changes in an embryo

Question 24

some diagnostic criteria for fetal alcohol spectrum disorder

Answer 24

• hard to pinpoint and diagnose
• overlap with ADHD for example
• some criteria:
  –> hyperactive
  –> attention difficulty
  –> poorer memory
  –> struggle in school
  –> low IQ or intellectual disability
  –> poor reasoning and judgment skills
  –> problems with heart, kidneys or bones etc…

Question 25

what is intellectual disability?

Answer 25

• is a diagnosis on its own
• often co-occurs with other neurodevelopmental conditions (e.g. Autism or FASD)
• affects approx. 10.4 people in every 1000 (1.4%)
• diagnosis is based on IQ evaluation as well as investigation of adaptive behaviour
  –> classified as mild (52-69), moderate (36-51), severe (20-35) or profound (<19)

Question 26

different domains of diagnosing intellectual disability

Answer 26

1. conceptual
   –> academic success
   –> planning
   —> executive functioning
2. social
   –> friendships and relationships
   –> communication
3. practical
   –> coping in their day to day life
   - need a rounded picture of the individual
   - no genetic testing so need battery of tasks and clinician expertise

Question 27

ADHD and Autism

Answer 27

• no clear cause for ADHD or Autism
  –> likely to be numerous contributing factors
• as there is no clear cause, there isn’t a definitive test as with genetic conditions
• diagnosis is made by behavioural observations
  –> match this to list of criteria in DMS-5

Question 28

domains we test for in ADHD

Answer 28

• inattention
  –> hyper focus
  –> lack of attention
  –> can have issues with maintaining attention
  –> sustaining and disconnecting attention
• hyper activity and impulsivity

Question 29

domains we assess for in Autism

Answer 29

1. deficits in social communication and social interaction
2. restricted, repetitive patterns of behaviour, interests or activities

Question 30

what impairments do the ICD look for in autism

Answer 30

• impairments in social interaction
• impairments in communication
• repetitive behaviours within a narrow set of interests

Question 31

what 3 main cognitive theories of autism have emerged?

Answer 31

1. theory of mind hypothesis
2. executive function hypothesis
3. central coherence hypothesis