The four levels of intellectual disability, sometimes referred to as mental retardation, are mild, moderate, severe and profound. Persons suffering from any level of intellectual disability have an intelligence quotient below 70. Another characteristic of persons suffering from intellectual disability is difficulty functioning in society, states Healthline.
Persons suffering from mild intellectual disability have an IQ between 50 and 69. They may have trouble learning to talk, being independent, reading and writing. They are likely to benefit from special education, and once they have learned to communicate, they are generally able to do so rather effectively, according to Healthline.
Moderate intellectual disability occurs when patients have IQs between 35 and 49. Persons with a moderate intellectual disability have difficulty with communication, reading and writing, explains Healthline. They are unable to live alone; however, they are able to get around and are able to function in simple social activities.
Persons with severe intellectual ability have IQs between 20 and 34, and they have motor impairment and abnormalities within their central nervous systems. Profound intellectual disability involves an inability to respond to requests, immobility, inability to communicate verbally, and a need for constant care and supervision, according to Healthline.
Persons with profound intellectual disability have IQs of 19 or less. They are immobile, wear diapers, cannot care for themselves, use limited nonverbal communication and require constant supervision, explains Healthline.