Lecture 15: Neurodevelopmental Disorders

What are neurodevelopmental disorders?

Conditions that affect the development of the neurological system (CNS, brain) and impacts different aspects of cognitive functioning

When do neurodevelopmental disorders normally manifest?

Infancy/early childhood

What are the possible causes of neurodevelopmental disorders?

• Low birth weight

• Premature birth

• Environmental contaminants

• Fetal exposure to smoking, alcohol, drugs or certain medications

• Genetics

What are cures for neurodevelopmental disorders?

No cure. Medication and therapy can help

What is autism?

A spectrum of developmental disorders with a neurological basis in the brain

When is autism diagnosed at?

Around 18 months

What are some brain abnormalities in autism?

• Bigger head and brain sizes due to atypical cell divisions, cell loss and synaptic pruning

• Larger number of frontal cortex cells which causes abnormal social development

• Cerebellar abnormality which causes repetitive behaviours

• Fewer connections between regions and increased connections within the frontal area

What is ADHD?

A disorder defined by non-emotional symptoms

What are the types of ADHD?

Hyperactive-impulsive, inattentive or combined hyperactive-impulsive and inattentive

When is ADHD diagnosed?

Based on sex and type. Girls (6-12) are usually diagnosed later because they tend to have inattentive ADHD while boys (6-7) are diagnosed earlier because they tend to have hyperactive ADHD

Symptoms must be present in how many settings to diagnose ADHD?

Two or more settings

What are some brain abnormalities in ADHD?

• Brain maturation is much slower by about 3 years

• Decreased gray matter volume in several regions

What are intellectual disabilities?

A lifelong condition characterized by substantial cognitive and adaptive development delays that lead to abnormalities of brain structure or function

What is the most common cause of intellectual disabilities?

Alcohol

What type of delay is almost always present in intellectual disabilities

Language

What are the three main components of an intellectual disability?

• Significantly below average of intellectual functioning

• Deficits in adaptive skills

• Onset before 18 years old

What are the intellectual disabilities we talk about?

Fragile X, down syndrome and FASD

What is Fragile X?

A genetic disorder that results in developmental delays, learning disabilities, social and behavioural problems

What is the difference between males and females with Fragile X?

Females with Fragile X have milder cognitive and physical expressions of the disorder than males

What are the brain abnormalities of Fragile X?

• Cortical thinning

• Increase in ventricular size

• Lower gray matter volume in some regions

• Reduced connectivity

• Reduced functioning

What is down syndrome?

Most common genetic (chromosomal abnormality) developmental disorder that affects throughout their life. Results in multiple health and cognitive problems

What are some cognitive deficits in down syndrome?

• Impulsive behaviour

• Slow learning

• Poor judgement

• Shorter attention span

• Delayed language and speech development

• Will reach developmental milestones later than other kids

What are the brain abnormalities in down syndrome?

• Smaller brain volumes

• Smoother and simplified appearance of brain

• Reduced cortical surface area

• Increased cortical thickness

• Premature brain aging

What is FASD?

Impact of alcohol exposure on prenatal infants that results in ID, learning disabilities, facial feature abnormalities and other functioning disorders (ADHD, etc)

What are some cognitive deficits in FASD?

• Overall intelligence

• Executive functioning

• Learning and memory

• Visual-spatial functioning

• Attention

• Information processing

• Social and emotional processing

• Impulsivity and poor judgement

• Language

What are the brain abnormalities for FASD?

• Smaller brains

• Abnormal gyri

• Abnormal clusters of cells in the cortex

• Misaligned cells in the cortex