9 Assessment of adaptive functioning in children with complex conditions

Adaptive functioning & Intellectual Disability

A diagnosis of Intellectual Disability according to the Diagnostic & Statistical Manual of Mental Disorders, Version 5 (DSM-5) requires that the child must have one or more domains of adaptive functioning impaired (Conceptual, Social, or Practical). The DSM-5 recognizes that scores are not the only consideration in evaluating adaptive functioning: “Adaptive functioning is assessed using both clinical evaluation and individualized, culturally appropriate, psychometrically sound measures… Additional sources of information include educational, developmental, medical, and mental health evaluations. Scores from standardized measures and interview sources must be interpreted using clinical judgment” (DSM-5, p.37). Furthermore, a DSM diagnosis of intellectual disability requires a relationship between the cognitive and adaptive deficits: “To meet diagnostic criteria for intellectual disability, the deficits in adaptive functioning must be directly related to the intellectual impairments described in Criterion A” (DSM-5, p.38).

However, standardized measures of adaptive functioning (e.g., ABAS, VABS) are not designed to differentiate between limitations in functioning arising from cognitive impairments from those arising from the impact of motor or sensory impairments.  What do we need to consider when evaluating adaptive functioning in children with multiple, severe disabilities?

• When evaluating young children with complex disabilities, it is wise to be cautious about diagnosing intellectual disability. Due to their very different developmental experiences, we need to be cautious in predicting their developmental trajectory.  For example, a child who is blind will need to learn special skills to identify coins and keep track of different denominations of money. Thus, they are likely to learn this skill at an older age than a sighted child. A child with severe motor impairments will not have had the same opportunities to learn and practice independence skills compared to their peers. Overall, when we see children in their teenage years, we can be more confident in making a diagnosis when it is appropriate.
• Adaptive functioning is best evaluated through interview format (e.g., VABS interview). If adaptive functioning is done in an interview format, you will better be able to understand which supports are in place due to motor or sensory impairments. Further, an adaptive functioning interview is helpful as it can be depressing and frustrating for parents to fill out forms where questions do not apply to their children, and where they have to fill out “zero after zero”.
• Many questions on adaptive functioning forms will be inappropriate for children with motor or sensory impairments (e.g., “carries dishes to the sink” for those without the physical ability to lift dishes; “uses spoon without spilling” in a child who is tube fed, “stays on sidewalk” in a child who is pushed in a wheelchair). Guidance from the measures themselves suggest that if a child is not capable of doing something due to a physical condition, the item must be scored as “0” but that you should take this into account in your interpretation.
• Do allow for a child’s use of sign language, braille, or adaptive equipment to communicate (if used independently and unprompted). This includes listening to audiobooks and screen readers for those with visual impairments (VABS-3 Manual, p.45). The ABAS manual does not discuss this topic, but a similar approach between the tests would be appropriate.
• If you are finding the question of a possible intellectual disability to be a tricky one in a particular child, it will be important to do a detailed examination of individual items on adaptive functioning measures.  For children with severe motor impairments, some subdomains of adaptive functioning are very low due to the motor impairments (e.g., for a child who can not dress or toilet independently). If that is the case, it is helpful to look particularly at the level of independence in the social and leisure domains, or the communication domain if language is not severely impaired. It is essential that you look at the scores in the context of the child’s experiences, opportunities, and current functioning. Observations and interviews are essential compliments to adaptive functioning forms.
• Be very cautious about interpreting age equivalents which may be calculated as part of adaptive functioning measures, particularly for children with sensory and motor impairments where you often see a lot of intra-subtest variability. See the section on age equivalents for more information on this topic.
• For discussion of evaluating the level of intellectual disability (mild, moderate, severe, profound, please see the next section – here.)