Munson Health
Intellectual Disability

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by de la Rocha K

(Cognitive Disability; Developmental Disability; Mental Retardation)



Several hundred causes of intellectual disability have been discovered, but many are still unknown. The most common ones are:
Double-stranded piece of DNA
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Head Injury in Child
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Symptoms appear before a child reaches age 18. Symptoms vary depending on the degree of the intellectual disability. If you think your child has any of these symptoms, do not assume it is due to intellectual disability. These symptoms may be caused by other, less serious health conditions.
Symptoms include:
  • Learning and developing more slowly than other children of the same age
  • Difficulty communicating or socializing with others
  • Lower than average scores on IQ tests
  • Trouble learning in school
  • Inability to do everyday things like getting dressed or using the bathroom without help
  • Difficulty hearing, seeing, walking, or talking
  • Inability to think logically
The following categories are often used to describe the level of intellectual disability:


  • IQ 50-70
  • Slower than normal in all areas
  • No unusual physical signs
  • Can learn practical skills
  • Reading and math skills up to grades 3-6
  • Can conform socially
  • Can learn daily task skills
  • Functions in society


  • IQ 35-49
  • Noticeable delays, particularly speech
  • May have unusual physical signs
  • Can learn simple communication
  • Can learn elementary health and safety skills
  • Can participate in simple activities and self-care
  • Can perform supervised tasks
  • Can travel alone to familiar places


  • IQ 20-34
  • Significant delays in some areas; may walk late
  • Little or no communication skills, but some understanding of speech with some response
  • Can be taught daily routines and repetitive activities
  • May be trained in simple self-care
  • Needs direction and supervision socially


  • IQ <20
  • Significant delays in all areas
  • Congenital abnormalities present
  • Needs close supervision
  • Requires attendant care
  • May respond to regular physical and social activity
  • Not capable of self-care


To help reduce your child’s chance of becoming intellectually disabled, take the following steps:
  • During pregnancy:
    • If you smoke, quit .
    • Don’t drink alcohol or use drugs.
    • Eat a healthful diet —one that is low in saturated fat and rich in whole grains, fruits, and vegetables.
    • Add extra folic acid to your diet.
    • See your doctor regularly.
  • After birth:
    • Have your newborn screened for conditions that may produce intellectual disability.
    • Have your child properly immunized .
    • Schedule regular visits to the pediatrician.
    • Use child safety seats and bicycle helmets.
    • Remove lead-based paint from your home.
    • Keep poisonous household products out of reach .
    • Aspirin is not recommended for children or teens with a current or recent viral infection. This is because of the risk of Reye's syndrome , which can cause neurological problems. Ask your doctor which medicines are safe for your child.


The Arc

American Association of Intellectual and Developmental Disabilities



Canadian Psychological Association

Special Olympics Canada



Causes and prevention of intellectual disabilities. The Arc website. Available at: . Updated March 1, 2011. Accessed February 20, 2013.

Daily D, Ardinger H, Holmes G. Identification and evaluation of mental retardation. Am Fam Physician . 2000;61(4):1059-67. Available at: . Accessed February 20, 2013.

Intellectual disability fact sheet. The Centers for Disease Control and Prevention website. Available at: . Accessed February 20, 2013.

Intellectual disability. National Dissemination Center for Children with Disabilities website. Available at: . Updated January 2011. Accessed February 20, 2013.

Shapiro BK, Batshaw ML. Mental retardation (intellectual disability). In: Nelson Textbook of Pediatrics . 18th ed. Philadelphia, PA: Saunders; 2007.

Questions and answers about persons with intellectual disabilities in the workplace. US Equal Employment Opportunities Commission website. Available at: . Updated March 17, 2011. Accessed February 20, 2013.


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