Diagnostic Adaptive Behavior Scale
Intellectual disability is a disability characterized by significant limitations both in intellectual functioning (reasoning, learning, problem solving) and in adaptive behavior, which covers a range of everyday social and practical skills. This disability originates before the age of 18.
"Developmental Disabilities" is an umbrella term that includes intellectual disability but also includes other disabilities that are apparent during childhood.
Developmental disabilities are severe chronic disabilities that can be cognitive or physical or both. The disabilities appear before the age of 22 and are likely to be lifelong.Some developmental disabilities are largely physical issues, such as cerebral palsy or epilepsy. Some individuals may have a condition that includes a physical and intellectual disability, for example Down syndrome or fetal alcohol syndrome.
Intellectual disability encompasses the “cognitive” part of this definition, that is, a disability that is broadly related to thought processes. Because intellectual and other developmental disabilities often co-occur, intellectual disability professionals often work with people who have both types of disabilities.
The evaluation and classification intellectual disability is a complex issue. There are three major criteria for intellectual disability: significant limitations in intellectual functioning, significant limitations in adaptive behavior, and onset before the age of 18.
The IQ test is a major tool in measuring intellectual functioning, which is the mental capacity for learning, reasoning, problem solving, and so on. A test score below or around 70—or as high as 75—indicates a limitation in intellectual functioning.
Other tests determine limitations in adaptive behavior, which covers three types of skills:
- Conceptual skills—language and literacy; money, time, and number concepts; and self-direction
- Social skills—interpersonal skills, social responsibility, self-esteem, gullibility, naïveté (i.e., wariness), social problem solving, and the ability to follow rules, obey laws, and avoid being victimized
- Practical skills—activities of daily living (personal care), occupational skills, healthcare, travel/transportation, schedules/routines, safety, use of money, use of the telephone
AAIDD publishes the most advanced scientific thinking on this matter in the 11th edition of its manual, Intellectual Disability: Definition, Classification, and Systems of Supports. In defining and assessing intellectual disability, AAIDD stresses that, in addtion to an assessement of intellectual functioning and adaptive behavior, professionals must consider such factors as
- community environment typical of the individual’s peers and culture
- linguistic diversity
- cultural differences in the way people communicate, move, and behavior
AAIDD’s new Diagnostic Adaptive Behavior Scale (DABS) scheduled to be released in 2015 provides a comprehensive standardized assessment of adaptive behavior. Designed for use with individuals from 4 to 21 years old, DABS provides precise diagnostic information around the cutoff point where an individual is deemed to have “significant limitations” in adaptive behavior. The presence of such limitations is one of the measures of intellectual disability.
Adaptive behavior is the collection of conceptual, social, and practical skills that all people learn in order to function in their daily lives. DABS measures these three domains:
- Conceptual skills: literacy; self-direction; and concepts of number, money, and time
- Social skills: interpersonal skills, social responsibility, self-esteem, gullibility, naïveté (i.e., wariness), social problem solving, following rules, obeying laws, and avoiding being victimized
- Practical skills: activities of daily living (personal care), occupational skills, use of money, safety, health care, travel/transportation, schedules/routines, and use of the telephone
The DABS focuses on the critical ‘cut-off area’ for the purpose of ruling in or ruling out a diagnosis of intellectual disability or related developmental disability. Professionals likely to use it include school psychologists, forensic psychologists, clinical psychologists, psychometricians, social workers, occupational therapists, and pediatricians, as well as officials in disability-related government agencies.
The purpose of establishing a diagnosis of intellectual disability is to determine eligibility for:
- Special education services
- Home and community-based waiver services
- Social Security Administration benefits
- Specific treatment within the criminal justice system (e.g., In 2002, the U.S. Supreme Court ruled in Atkins v. Virginia that executing the mentally retarded violates the Eighth Amendment’s ban on cruel and unusual punishment)
American Association on Intellectual and Developmental Disabilities