Types of Intellectual Disabilities
There is a diverse array of levels of Intellectual Disabilities. Profound, severe, and moderate (considered lower functioning) are the most easily to recognize as being developmentally slow (child like in a way but in adult bodies). Mild and borderline Intellectually Disabilities (considered high functioning) is less clear. They may have matured in some ways (as comparable as a 6 year old) but not in all areas.
Mild Intellectual Disabilities
IQ ranges from 50-70 and consist of 85% of DD population. Mental age ranges from one to five years and speech is often functional or they are able to effectively use a communication device. They are capable of meaningful though somewhat immature relationships with peers and the opposite sex and can achieve up to sixth grade level by late teens (average achievement is third grade). They also have poor decision-making and problem solving skills. In the work world they usually can maintain minimum self-support; some achieve semi-skilled or helper status; others capable of unskilled employment. Others have disability, medical and back supports from regional center. Some marry, become parents, and maintain an independent adjustment but may need assistance during periods of stress.
Moderate Intellectual Disabilities
IQ ranges from 35-50 and consist of 10% of DD population. Mental age range is from one to five years. Language is functional though intelligibility may be much impaired. They can often use a communication device in a limited capacity. Self-help skills are partial to nearly complete. Social skills: diminished ability to form relationships. May only distinguish own needs and wants, disregarding those of others. In school they are unlikely to progress beyond second grade level. They are capable of some degree of productive unskilled or semi skilled work performed under close supervision or in sheltered workshops. May learn to travel alone in familiar places. As adults they usually do not marry. They are capable of the degree of self-management necessary for independent living. They adapt well to life in the community living in their parent's home or supervised community group homes.
Severe Intellectual Disabilities
IQ range 20-35 and consist of 5% of DD population. Mental age is average two months to one year and there is very little communicative speech but can often say simple phrases. Self-help skills are poor. They are capable of forming emotional bonds with peers and staff and are often internally motivated. They can become familiar with the alphabet, counting, and can learn sight-reading of some survival words. They often attend activity center programs with constant supervision. As adults they are dependent on others to care for them and will always need supervision, often they live with family or in a group home in community.
Profound Intellectual Disabilities
IQ below 20 and consist of 1-2% of the DD population. Mental age is usually zero to six months. They have little to no commutative speech. They are sometimes able to understand simple concrete directions and require assistance from staff to care for all basic needs. They are very internally motivated and may make repetitive movements for self-stimulation. They usually have no academic or vocational skills. As adults they will always will need close supervision and a lot of daily routine structure to function