Assessment of learning disabilities in adults should be evidence-based
Most clinicians are aware that learning disabilities arise early in development, are presumed to be neurologically based and often run in families. Yet, when reviewing reports I am frequently surprised to see that many clinicians are not aware of the evidence base on these disorders. Statements I have found in reports include:
- Test scatter indicates that Mr. White has a learning disability.
- Mr. Smith’s reading disorder is due to his slow processing speed.
- Ms. Jones’s reading disorder is directly related to her visuospatial difficulties.
- Ms. Adams’s profile indicates a learning disability in processing speed, conceptual
thinking and visuospatial skills.
None of these statements is correct. Specifically, research has found that 1) variability in test performance is the rule rather than the exception and is not diagnostic of a
learning disability, 2) slow processing speed is associated with dyslexia or ADHD and may reflect their genetic linkage but does not cause either and 3) visuospatial difficulties may accompany reading disorders but do not cause them, as they are rooted in the language system of the brain.
Learning disabilities also cannot be arbitrarily diagnosed based on a cobbling together of weaknesses found on testing. Rather, only learning disabilities for which there is
empirical support should be diagnosed, and there should be associated empirically based weaknesses in cognitive functioning.
Research on learning disabilities in children is well established. Over the past 15 years, research on these disorders in adults has grown substantially. Moreover, much of
what has been found to be true in children has also been found to be true in adults.
Consequently, much of what we know about children can, in combination with research on adults, be applied to assessment of adults. Clinicians who routinely evaluate adults for learning disabilities should be familiar with this research.
The following applies this research to clinical assessment. References to this work will be provided on request.