Approximately 85% of the mentally retarded population is in the mildly retarded category. Their IQ score ranges from 50-70, and they can often acquire academic skills up to about the sixth-grade...
Could be a number of things....
1. Enviromental Toxins
2. In Utero Drug and Alcohol Exposure
3. Malnutrition
4. Brain Damage (Head Injury)
5. Poverty
6. In Utero Exposure to Diabetes
7....
Only 1-2% of the mentally retarded population is classified as profoundly retarded. These individuals have IQ scores under 20-25. They may be able to develop basic self-care and communication skills...
Mental retardation is a developmental disability that first appears in children under the age of 18. It is defined as an intellectual functioning level (as measured by standard tests for intelligence...