Intellectual & Developmental Disabilities

Overview

Developmental disabilities (DDs) are often severe, lifelong conditions due to physical, learning, language or behavioral impairment. Most DDs begin before a baby is born, but some occur after birth due to injury, infection or other factors. Such disabilities can affect day-to-day functioning, include significant behavioral challenges and usually last throughout life.

DDs occur among all racial, ethnic and socioeconomic groups. Approximately 1 in 6 children, ages 3-17—about 17% of all U.S. children—has a physical or mental impairment, including:

- Attention-deficit/hyperactivity disorder (ADHD)
- Autism spectrum disorder (ASD)
- Cerebral palsy
- Intellectual or learning disability
- Hearing loss or vision impairment
- Other developmental delays

A narrower subset of DDs are intellectual and developmental disabilities (IDDs). Starting before age 18, IDD types may vary based on the source of information—but all are typically characterized by differences with:

1. Intellectual functioning or intelligence, including ability to learn, reason, problem solve and other skills

2. Adaptive behavior, including everyday social and life skills

Children and adults with disabilities can be well, active and a part of the community. They can get the tools and information to make healthy choices, learn how to prevent illness and manage related, functional limitations in such of activities as:

- - Self-care
  - Receptive and expressive language
  - Learning
  - Mobility
  - Self-direction
  - Capacity for independent living
  - Economic self-sufficiency

Common known causes of DDs

Specific causes of most developmental disabilities are unknown and likely result from interaction between genetic, environmental and social factors:

Prenatal exposure to substances, such as smoking and drinking. Fetal alcohol syndrome is caused from maternal drinking during pregnancy

Genetic and chromosomal abnormalities, causing such conditions as Down syndrome, Rett syndrome or Fragile X syndrome

Certain infections in pregnancy or in the baby’s first months

Increased risk for IDDs

Research has identified factors that may put children at risk for ASD and other DDs:

- Parental health
- Low birthweight, premature birth, multiple birth and infections during pregnancy
- Exposure of mother or child to high levels of environmental toxins, such as lead
- Children with a sibling with ASD are at higher risk of having ASD
- Untreated newborn jaundice causing brain damage and possibly cerebral palsy and hearing, vision and teeth problems

4 Bodily Systems Affecting IDDs

Nervous system disorders affect how the brain, spinal cord and nervous system function, which can affect intelligence and learning.

- Can also cause behavioral disorders, speech or language difficulties, seizures, trouble with movement.
- Includes cerebral palsy, Down syndrome, Fragile X syndrome and ASD.

Sensory system disorders affect the senses or how the brain processes or interprets sensory information.

- Infants born preterm or exposed to infections may have problems with eyesight and/or hearing.
- Being touched or held can be difficult for people with ASD.

Metabolism disorders affect how the body uses food and other materials for energy and growth.

- Problems with digestion and other processes upsetting the balance: too much of one thing or too little of another can disrupt overall body and brain functions.
- Examples: phenylketonuria (PKU) and congenital hypothyroidism

Degenerative disorders may show up later, after birth or early developmental milestones—even as late as adolescence or adulthood

- Can disrupt skills, abilities and functions.
- Can result from other conditions, such as untreated problems of metabolism.

What are the symptoms of Intellectual Developmental Disorders?

Related behavioral challenges in children, adolescents and adults with intellectual and developmental disabilities include:

- Aggressive, disruptive or stereotyped (repetitive acts) behaviors
- Harmful or dangerous behavior to self, others or environment
- Behaviors that limit opportunities to participate, be included or integrated in daily life

Such challenging behaviors can occur when:

- Health, developmental and personal needs are not fully understood
- Necessary supports are not available
- Expectations might be inappropriate
- Needed environmental accommodations are not made

Communication Challenges

Some individuals with IDD—up to 1/3 of whom might also have ASD—lack verbal or conventional nonverbal ways to express needs, difficulties or feelings, such as happiness or distress. Instead, caregivers must infer what is being communicated from nonverbal vocalizations, body language and unusual behaviors. For example:

- Expression of pain
- Desire for a preferred activity
- Avoidance of a noisy environment

In people with DD, IDD and ASD, sensory hypersensitivities and hyposensitivities are extremely common and can trigger challenging behaviors. They can also go unrecognized and thus untreated.

Evaluation & Treatment

Evaluation

Before a treatment plan can be tailored to a person with a developmental disability, healthcare and education specialists need to make a rigorous assessment of both the individual’s and the environment’s conditions and the individual’s physical, mental and behavioral needs.

Treatment

While there is no cure, treatment can be effective in making symptoms less severe and more manageable—so individuals can lead full and productive lives. Untreated symptoms typically worsen over time, so early intervention is key. Some impairments may require lifelong or extended supports or assistance.

There are many treatment options for managing DDs, including:

Physical therapy: Exercises to improve gross- and fine-motor skills

Speech therapy: Exercises to improve speech or adapt to alternative communication methods

Occupational therapy: Exercises to improve motor skills, cognitive skills, sensory processing and communication and play skills

Cognitive behavioral therapy (CBT): Psychological treatments to help change potentially self-destructive or unhealthy thoughts and behaviors, as well as to treat related anxiety and depression

Educational intervention: Special education and attention to help with learning disorders and other academic difficulties, including school observation and consultation, planning for independent education plans (IEPs/504 plans) and school placement

For children ages 3 and older: Local school systems can help diagnose and evaluate educational needs, as part of the Individuals with the federal Disabilities Education Act (IDEA)

For children under age 3: Local early-intervention agencies can help

Social skills building: Efforts of parents, educators and healthcare practitioners to encourage social contact and communication.

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References

Better Health

Centers for Disease Control and Prevention (CDC) on chronic diseases

Centers for Disease Control and Prevention (CDC) on developmental disabilities

CDC Study to Explore Early Development (SEED)

National Association of Chronic Disease Directors (NACDD)

National Institute of Child Health and Human Development (NICHD)