Intellectual Disability
(Cognitive Disability; Developmental Disability; Mental Retardation)
Definition
Causes
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Biomedical causes resulting from:
- Abnormal genes inherited from parents
- Errors when genes combine, such as Down syndrome and Fragile X syndrome
- Nutritional deficiencies
- Metabolic conditions, such as phenylketonuria (PKU), galactosemia , and congenital hypothyroidism
- Developmental brain abnormality, such as hydrocephalus and brain malformation
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Infections during pregnancy, such as:
- HIV
- Toxoplasmosis
- Herpes simplex
- Rubella
- Syphilis
- CMV infection
- Behavioral issues during pregnancy, such as:
-
Problems at birth, such as:
- Premature delivery or low birth weight
- Baby doesn’t get enough oxygen during birth
- Baby is injured during birth
-
Factors during childhood, such as:
- Nutritional deficiencies
- Illnesses or infections that affect the brain, including meningitis , encephalitis , chickenpox , whooping cough , and measles
- Exposure to lead , mercury , and other toxins
- Head injury or near drowning
- Social factors, such as child stimulation and adult responsiveness
- Educational deficiencies
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Risk Factors
Symptoms
- 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
Mild
- 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
Moderate
- 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
Severe
- 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
Profound
- 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
Diagnosis
- Intelligence—IQ tests measure a person’s ability to do things such as think abstractly, learn, and solve problems. A child may have intellectual disability if IQ test results are 70 or below.
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Adaptive behavior—These are skills needed to function in everyday life, including:
- Conceptual skills like reading and writing
- Social skills like responsibility and self-esteem
- Practical skills like the ability to eat, use the bathroom, and get dressed
Treatment
- Early intervention programming for infants and toddlers up to age three
- Family counseling
- Human development training, including emotional skills and hand-eye coordination
- Special education programs
- Life skills training, such as preparing food, bathing
- Job coaching
- Social opportunities
- Housing services
Prevention
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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.
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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.
RESOURCES
The Arc http://www.thearc.org
American Association of Intellectual and Developmental Disabilities http://www.aaidd.org
CANADIAN RESOURCES
Canadian Psychological Association http://www.cpa.ca
Special Olympics Canada http://www.specialolympics.ca
References
Causes and prevention of intellectual disabilities. The Arc website. Available at: http://www.thearc.org/page.aspx?pid=2453 . 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: http://www.aafp.org/afp/20000215/1059.html . Accessed February 20, 2013.
Intellectual disability fact sheet. The Centers for Disease Control and Prevention website. Available at: http://www.cdc.gov/ncbddd/dd/ddmr.htm . Accessed February 20, 2013.
Intellectual disability. National Dissemination Center for Children with Disabilities website. Available at: http://nichcy.org/disability/specific/intellectual . 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: http://www.eeoc.gov/facts/intellectual%5Fdisabilities.html . Updated March 17, 2011. Accessed February 20, 2013.