Mental retardation

Mental retardation refers to below-average intelligence. The diagnosis of mental retardation is based on intelligence quotient (IQ) tests and a child's learning problems.

Mental retardation is categorized according to IQ scores:

• In mild retardation, IQs range from 50 or 55 to 70.
• In moderate retardation, IQs range from 35 or 40 to 50 or 55.
• In severe retardation, IQs range from 20 or 25 to 35 or 40.
• In profound retardation, IQs are below 20 or 25.

Most people with mental retardation have mild retardation. Very few have severe or profound mental retardation.

Children with mental retardation may have difficulty with:

• Learning, especially complex tasks.
• Language. Children with severe mental retardation have more difficulty learning language than children with mild to moderate mental retardation.
• Self-care (in cases of severe mental retardation).