Intellectual disability is a disability characterized by significant limitations both in intellectual functioning and in adaptive behavior, which covers many everyday social and practical skills. These limitations will cause a child to learn and develop more slowly than a typical child. This disability originates before the age of 18.
Intellectual functioning—also called intelligence—refers to general mental capacity, such as learning, reasoning, and problem solving.
Adaptive behavior comprises three skill types:
- Conceptual skills—language and literacy; money, time, and number concepts; and self-direction.
- Social skills—interpersonal skills, social responsibility, self-esteem, gullibility, naïveté (i.e., wariness), social problem solving, and the ability to follow rules/obey laws and to avoid being victimized.
- Practical skills—activities of daily living (personal care), occupational skills, healthcare, travel/transportation, schedules/routines, safety, use of money, use of the telephone.
Children with an intellectual disability may:
- sit up, crawl, or walk later than other children
- learn to talk later, or have trouble speaking
- find it hard to remember things
- not understand how to pay for things
- have trouble understanding social rules
- have trouble seeing the consequences of their actions
- have trouble solving problems
- have trouble thinking logically
Doctors have found many causes of intellectual disabilities. The most common are:
- Genetic conditions. Sometimes an intellectual disability is caused by abnormal genes inherited from parents, errors when genes combine, or other reasons. Examples of genetic conditions are Down syndrome, fragile X syndrome, and phenylketonuria (PKU).
- Problems during pregnancy. An intellectual disability can result when the baby does not develop inside the mother properly. For example, there may be a problem with the way the baby’s cells divide as it grows. A woman who drinks alcohol or gets an infection like rubella during pregnancy may also have a baby with an intellectual disability.
- Problems at birth. If a baby has problems during labor and birth, such as not getting enough oxygen, he or she may have an intellectual disability.
- Health problems. Diseases like whooping cough, the measles, or meningitis can cause intellectual disabilities. They can also be caused by extreme malnutrition (not eating right), not getting enough medical care, or by being exposed to poisons like lead or mercury.
Implications for speech and language:
Children with an intellectual disability exhibit delays in language development.
Children and adults with an intellectual disability may need assistance with:
- following and understanding directions
- using and understanding spoken and written language
- learning new information
- understanding detailed information
- completing tasks/documents
Communication strategies can be used to facilitate communication with a person with an intellectual disability. When communicating with a person with an intellectual disability, it is important to acknowledge that each person is an individual and should be approached as such. Speak clearly, using simple language. Check for understanding by asking them to repeat instructions several times. Break each task into steps and illustrate each step. Don’t assume they will transfer knowledge gained in one task or another. Use visual cues (pictures or graphics) where possible. If there is a support person, address the person with a disability and not the support person. Provide a lot of encouragement and monitor on a regular basis.
Diagnosing this disorder:
Speech Pathologists do not diagnose an intellectual disability. One criterion to measure intellectual functioning is an IQ test. Generally, an IQ test score of around 70 or as high as 75 indicates a limitation in intellectual functioning. Standardized tests may be used to determine limitations in adaptive skills. On the basis of such many-sided evaluations, professionals can determine whether an individual has an intellectual disability and can tailor a support plan for each individual. But in defining and assessing intellectual disability, professionals must take additional factors into account, such as the community environment typical of the individual’s peers and culture. Professionals should also consider linguistic diversity and cultural differences in the way people communicate, move, and behave. Finally, assessments must also assume that limitations in individuals often coexist with strengths, and that a person’s level of life functioning will improve if appropriate personalized supports are provided over a sustained period.
- American Association of Intellectual and Developmental Disabilities (800) 424-3688
- National Dissemination Center for Children with Disabilities (800) 695-0285
- The ARC (800) 433-5255
- Centers for Disease Control and Prevention (800) CDC-INFO
- Graduate School Success for Students with Disabilities. This guide highlights scholarships, available resources and expert insight for completing an advanced degree.
Books for kids:
- I Can, Can You?, by Marjorie W. Pitzer
- Kids Like Me…Learn ABCs or Kids Like Me…Learn Colors, by Laura Ronay
- Families or Eating the Rainbow, by Rena D. Grossman
- Dr. Seuss’s ABC
- Feelings, by Susan Canizares
- The Feelings Book, by Todd Parr
- Hugs and Kisses, by Roberta Grobel Intrater
- My Very First Book of Colors, My Very First Book of Numbers, My Very First Book of Shapes, by Eric Carle
For children about intellectual disabilities:
- Hi, I’m Ben and…I’ve Got a Secret, by Julie A. Bouwkamp (Ages 3–8)
- My Friend Isabelle, by Eliza Woloson (Ages 4–8)
- Susan Laughs, by Jeanne Willis (Ages 4–8)
Books for Parents:
- Babies with Down Syndrome: A New Parent’s Guide, edited by Susan Skallerup
- Children with Mental Retardation: A Parents’ Guide, edited by Romayne Smith
- Early Communication Skills for Children with Down Syndrome: A Guide for Parents and Professionals, by Libby Kumin, Ph.D.
Do you have more great resources for families or community members? We would be happy to add any great resources to this webpage. Please email us with the link or content.