Intellectual disability (also called mental retardation) is often poorly understood because its effects vary greatly among those who have it. Many people with intellectual disability are mildly affected. They are only a little slower than average in learning new information and skills. As children, their intellectual disability is not readily apparent and may not be identified until they enter school. As adults, many are able to lead somewhat independent lives.
People with intellectual disability who have a very low intelligence quotient (IQ) have serious limitations in their ability to function. However, with early intervention and appropriate support, they can also lead satisfying lives.
Intellectual disability begins in childhood and is characterized by limitations in both intelligence and adaptive skills. The following three criteria must be met for a diagnosis of intellectual disability:
Any condition that impairs development of the brain before birth, during birth, or during childhood can cause intellectual disability. The main causes can be categorized as follows:
Genetic abnormalities may be inherited from parents or may be caused by environmental factors. More than 500 genetic diseases are associated with intellectual disability. Examples include:
Use of alcohol or drugs by a pregnant mother can cause intellectual disability. Smoking can increase the risk, as well. Other risks during pregnancy include:
Prematurity and low birth weight may sometimes lead to intellectual disability. These conditions may be associated with bleeding in or around the brain. However, other birth conditions or physical stress in the newborn stage may injure an infant's brain.
Other conditions that can damage a child's brain and possibly lead to intellectual disability include:
In addition, poisoning from lead , mercury , carbon monoxide , and other environmental toxins can cause permanent damage to a child's brain and nervous system.
Children in poor families may become mentally retarded because of:
The American Association on Intellectual and Developmental Disabilities (AAIDD) has a process for diagnosing and classifying a person with intellectual disability. This process involves assessing the person's IQ and adaptive skills. Adaptive skills fall into three categories:
The best assistance for people with intellectual disability begins with diagnosis and help early in life. Treatment includes:
With enough education and support, many people with intellectual disability can learn to take care of their basic needs and to live in the community.
Newborn screening followed by proper treatment can prevent intellectual disability resulting from certain conditions. Examples include:
Vaccines can prevent certain infectious diseases that may lead to intellectual disability, such as:
Other interventions that can reduce the risk of intellectual disability include:
RESOURCES:
American Association on Intellectual and Developmental Disabilities
http://www.aaidd.org/
Developmental Disabilities
Centers for Disease Control and Prevention
http://www.cdc.gov/ncbddd/dd/default.htm/
CANADIAN RESOURCES:
Best Buddies
http://www.bestbuddies.ca/
Live, Work, Play
http://www.liveworkplay.ca/
References:
The AAIDD definition. American Association on Intellectual Disability website. Available at: http://www.aamr.org/ . Accessed June 17, 2008.
The ARC website. Available at: http://www.thearc.org/
Children who are mentally retarded. The American Academy of Child and Adolescent Psychiatry website. Available at: http://www.aacap.org . Updated July 2004. Accessed June 17, 2008.
Diabetes and other endocrine and metabolic disorders. University of Virginia Health System website. Available at: http://www.healthsystem.virginia.edu/UVAHealth/peds_diabetes/hypothd.cfm. Updated February 2004. Accessed April 14, 2010.
Diagnostic adaptive behavior scale. American Association on Intellectual and Developmental Disabilities website. Available at: http://www.aaidd.org/intellectualdisabilitybook/content_2687.cfm?navID=283. Accessed April 14, 2010.
Intellectual disability. EBSCO Health Library website. Available at: http://www.ebscohost.com/thisTopic.php?marketID=15topicID=81 . Updated January 2010. Accessed April 14, 2010.
Intellectual disability. Kronkosky Charitable Foundation website. Available at: http://www.kronkosky.org/research/Research_Briefs/Intellectual%20Disability%20May%202009.pdf. Published May 2009. Accessed April 14, 2010.
Intellectual disability. National Dissemination Center for Children With Disabilities website. Available at: http://www.nichcy.org/Disabilities/Specific/pages/IntellectualDisability.aspx. Accessed April 14, 2010.
Mental retardation. FAQS website. Available at: http://www.faqs.org/health/topics/37/Mental-retardation.html. Accessed April 14, 2010.
Mental retardation. Merck website. Available at: http://www.merck.com/mmhe/sec23/ch285/ch285a.html#sec23-ch285-ch285a-1552. Updated October 2006. Accessed April 14, 2010.
Last reviewed May2010 by Brian Randall, MD
Please be aware that this information is provided to supplement the care provided by your physician. It is neither intended nor implied to be a substitute for professional medical advice. CALL YOUR HEALTHCARE PROVIDER IMMEDIATELY IF YOU THINK YOU MAY HAVE A MEDICAL EMERGENCY. Always seek the advice of your physician or other qualified health provider prior to starting any new treatment or with any questions you may have regarding a medical condition.
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