According to the American Psychiatric Association, the intellectually disabled have considerable intellectual deficits as evidenced by substandard IQ scores. An IQ of less than 70 supports a diagnosis into one of the four categories of intellectual disability: mild, moderate, severe or profound. Although an IQ score plays a large role in qualifying someone as intellectually disabled or challenged, there are other significant symptoms to consider.
The New York Child Study Center reports that cognitive abilities differ widely across the four categories of intellectual disability. The mildly intellectually disabled are considered to be "educable," meaning that they can achieve academically at about a sixth-grade level. The moderately intellectually disabled have the capacity to acquire academic skills comparable to those of a non-impaired second grade student, which would include basic counting, telling time and recognizing commonly used words. The severely intellectually disabled can acquire some speech and may be able to recognize a few words, but they do not have the cognitive abilities to learn any academic skills such as reading. The profoundly intellectually disabled are unable to communicate.
Physical symptoms dependent upon the severity of the intellectual disability. The mildly intellectually disabled may not appear to be impaired at all, exhibiting no physical symptoms. The other forms of intellectual disability are usually associated with deformities of the face or head. In some cases, the forehead is sloped, the bridge of the nose is flat and the ears appear larger or smaller than normal.
Adaptive functioning refers to skills that are of a practical or social nature, such as the ability to earn a living and care for oneself. Intellectually disabled adults may be employed at minimum wage jobs and can likely be self-supporting. The majority who work favor independent living over group or supervised living situations. Moderately intellectually disabled typically live with relatives or in a supervised group setting. The moderately intellectually disabled can learn limited vocational skills as participants in specialized training schools, but are not likely to be self-supporting. The limited capacity of the severely intellectually disabled only allows for the mastery of very basic hygiene tasks while supervised. The severely intellectually disabled are not candidates for independent living. The profoundly intellectually disabled are mostly non-communicative, and many are institutionalized due to their need for around-the-clock care.