Levels of Severity
The types of intellectual disabilities are actually different levels of severity, which differ by IQ score. These levels include mild, moderate, severe and profound intellectual disability. The DSM-IV-TR also includes “mental retardation, severity unspecified," in which the clinician has a strong feeling that the patient has an intellectual disability, but for some reason, such as the patient being too impaired or uncooperative, the clinician cannot test her successfully.
With a mild intellectual disability, the patient has an IQ between 52 and 69, and she can learn up to around the sixth grade level, notes the Merck Manual Home Edition. The next type of intellectual disability is moderate intellectual disability, in which the patient has an IQ of between 36 and 51. Children with a moderate intellectual disability can learn communication, but have poor social awareness. With severe intellectual disability, the patient's IQ is between 20 and 35, she she can speak a couple of words, but has poor motor coordination. The last type of intellectual disability, profound intellectual disability, involves an IQ of 19 or below. Children with this type have extremely limited cognition, according to the Merck Manual Home Edition.