Chapter 14 Neurodevelopmental Disorders

Disability (Intellectual Development Disorder)
Prevention of Neurodevelopmental Disorders

specific learning disorder?
What are the major features of autism spectrum

disorders?
How is intellectual disability defined?

deficit hyperactivity disorder (ADHD)
Specific learning disorder
Autism spectrum disorder
Intellectual Disability
Communication and

Motor Disorders

and environment of child
Developmental psychopathology
Study of how disorders arise and

change with time
Disruption of early skills can affect later development
Caution: do not excessively pathologize childhood behavior that is part of normal development

linked to stuttering

impulsivity
Associated with numerous impairments
Behavioral
Cognitive
Social and academic problems

children throughout the world
ADHD most commonly diagnosed in the United

States, although prevalence appears fairly constant worldwide
One study: 11% of children aged 4 to 17 were labeled with ADHD in 2011-2012
In general population (including adults), 5 to 9% meet criteria

24
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age 3 to 4
Half of children with ADHD continue to

have difficulties as adults
Divorce, lower education, substance use
Impulsivity decreases, but inattention remains
Gender differences: Boys outnumber girls 3:1

in families
Partially explained by copy number variants – extra or

missing copies of genes on chromosome
The role of toxins
Food additives (e.g., dyes, pesticides) may play very small role in hyperactive/impulsive behavior among children
Maternal smoking increases risk
Neurobiological correlates of ADHD
Inactivity of the frontal cortex and basal ganglia
Abnormal frontal lobe development, poor inhibitory control

negatively by others > Frequent negative feedback from peers and

adults
Peer rejection and resulting social isolation
Such factors foster low self-esteem

improve attention
Behavioral treatment for children
Reinforcement programs increase appropriate behaviors, decrease

inappropriate behaviors
May also involve parent training

in reading, mathematics, and/or writing
Performance substantially below expected levels based

on age and/or demonstrated capacity
Problems persist for 6+ months despite targeted intervention

accuracy
Reading rate or fluency
Reading comprehension
With impairment in written expression, may

include:
Spelling accuracy
Grammar punctuation and accuracy
Clarity/organization of written expression
With impairment in mathematics, may include:
Number sense
Memorization of arithmetic facts
Accurate or fluent calculation
Accurate math reasoning

across youth of various age and cultures
Highest rate of diagnosis

in wealthier regions, but children with low SES more likely to have difficulties
Reading difficulties most common, affect 7% of the general population

likely to:
Drop out of school
Be unemployed
Have suicidal thoughts
Have negative school

experiences
May be related to communication disorders

in families, but specific difficulties are not inherited
Evidence for subtle

neurological difficulties is mounting (e.g., decreased functioning of areas responsible for word recognition)
Overall, contributions are unclear
Performance also influenced by:
Motivational factors
Socioeconomic status
Cultural expectations
Parental interactions
Child management practices

processing problems, cognitive skills, and compensatory skills
Examples:
Vocabulary, discerning meaning, fact

finding, decision making, critical thinking
Data support behavioral educational interventions
Biological interventions (e.g., Ritalin) usually used only for those individuals who also have ADHD

problems span many life areas
25% don’t acquire effective speech
Restricted,

repetitive patterns of behavior, interests, or activities

classified as “pervasive developmental disorders”
Including:
Autistic disorder
Asperger’s disorder
Childhood disintegrative disorder
Rett

syndrome

develop age-appropriate social relationships
Trouble initiating and maintaining relationships
Trouble with

nonverbal communication
May lack appropriate expressions, tone
Trouble with social reciprocity
Deficits in joint attention – the ability to communicate interest in an external stimulus and another person at the same time

– maintenance of sameness
Severe forms: Stereotyped or ritualistic behavior
E.g., spinning,

waving hands, rocking
Less severe forms: Intense, circumscribed interest in very specific subjects
Having restricted areas of interest may compound difficulties relating to others

but this is not the case
1 in 50 school-aged children

meet criteria
More commonly diagnosed in males
Gender ratio: 4 to 5:1
IQ interaction
38% show intellectual disabilities
Occurs worldwide
The better the language skills and IQ test performance, the better the prognosis

thought to have high socioeconomic status and higher IQs
This view

is not currently supportive

with autism, the chance of having a second child with

autism is 20% (100x greater risk than general population)
Numerous genes on several chromosomes involved
Older parents associated with increased risk

cortisol
Neuronal damage in the amygdala results from high stress, which

may affect processing of social situations
Oxytocin
Lower levels in individuals with ASD
giving oxytocin to people with ASD improved their ability to remember and process infor- mation with emotion content

the risk of autism
Mercury in some vaccinations was rumored to

increase autism risk
Large scale studies do NOT support this
High rates of vaccinations do NOT increase risk for autism in the community at large
Health risk of not vaccinating is substantial

'have too many synapses in their brain'

Mutations in a gene

called UBE3A cause it to become hyperactive, leading to abnormal brain development and autism/ This hyperactivity causes autism
While the parents of the children had no UBE3A mutations, the children did. The UBE3A gene in the children was permanently switched on. Children and adolescents with autism have too many synapses in their brain, which can affect their brain function
Mutated UBE3A gene to mouse models the development of dendritic spines on the brain cells -too many dendritic spines has been associated with autism
Children with autism 'have too many synapses in their brain
In the brains of individuals without autism, the number of spines had reduced by almost 50% by late childhood. However, the number of spines in the brains of those with autism had only reduced by 16% by late childhood.

and language training
Increase socialization
Naturalistic teaching strategies
Early intervention is critical –

may “normalize” the functioning of the developing brain

little positive impact on core dysfunction
Some drugs decrease agitation
Tranquilizers

SSRIs
Indicators of good prognosis
High IQ, good language ability

comprehensive focus
Children offered special education at school focusing on

communication
Judicious use of medication in some cases
Families given support too
When older, focus on integrating into the community while maximizing independence

evident in childhood
Range of impairment varies greatly
Previously called mental retardation

of severity; IQ may be as low as under 20
Previously

diagnosed on DSM-IV Axis II
Reserved for conditions that 1) are chronic and pervasive and 2) are likely to influence the presentation of other mental disorders

= 35-40 to 50-55
Severe
IQs = 20-25 to 35-40
Profound
IQ = below

20 to 25

deficits in areas such as language, reasoning, knowledge, and memory)
Social

(e.g., problems with social judgment and the ability to make and retain friendships)
Practical (e.g., difficulties managing personal care or job responsibilities)
Devalued by society

Developmental Disabilities (AAIDD)
Based on assistance required
Intermittent
Limited
Extensive
Pervasive
Keeps the emphasis on what

assistance is needed

in 10 people with ID have mild impairment (IQ 50

to 70)
Chronic course
Highly variable individual prognosis
Independence is possible for many individuals with mild impairment when provided with appropriate resources (e.g., skills training)

exposures to toxins in the womb)
Perinatal (e.g., problems with delivery)
Postnatal

(e.g., head injury)

illness in the womb
Lack of oxygen (anoxia) during birth
Malnutrition

Head injuries
Childhood abuse

genetic mutations
Single genes can be responsible
Dominant genes less often responsible

for ID (because people with ID are less likely to have children)
Recessive genes more often responsible
As many as 30% cases of ID have no identified etiology

the sperm or egg or after fertilization)
Intellectual disability, symptoms of

cerebral palsy, self-injurious behavior
Recessive allele on the X chromosome > only affects males (females have an additional X chromosome to balance)

severity of developmental delay. 
The most common inborn error of amino

acid metabolism.
Sources of phenylalanine are eggs, chicken, liver, beef, milk, and soybeans

chromosomal cause of intellectual disability
Extra 21st chromosome (Trisomy 21)
Distinctive physical

symptoms

advanced maternal age
Detectable with some prenatal tests
Amniocentesis
Chorionic villus sampling (CVS)
Mother’s

blood tests
Tests do not indicate severity of impairment
1 in 4 mothers elects to terminate the pregnancy

attention span
Gaze avoidance
Perseverative speech
Gender differences
Primarily affects males
Women with Fragile X

have mild symptoms

to intellectual disability influenced by social environmental factors, such as:
Abuse
Neglect
Social

deprivation
These factors likely interact with existing biological factors

autism spectrum disorder
Mild ID: Treatment similar to that for learning

disorders
Goals are similar across severity; level of assistance differs
Behavioral interventions teach:
Basic skills (e.g., dressing, hygiene)
Social skills
Practical skills (e.g., paying bills)

education
Hold a job or other productive pursuits (e.g., volunteering)
Build meaningful

relationships

for at-risk children
Head Start Program: Educational, medical (e.g., nutritional), and

social support
Future directions: Genetic screening
Detection and correction
Prenatal gene therapy

disorders with varying severity
May be caused by genetic or environmental

factors or have indeterminate cause
Treatment focuses on mitigating functional impairment