Nonverbal learning disability (NLD) can present a diagnostic and treatment conundrum to the child psychiatrist, with children presenting with a number of symptoms and deficits that are common with other conditions.
While the definition of what exactly NLD is varies depending on the researcher or the clinician using it, it most commonly combines deficits in novel problem solving (eg, executive function), visual-spatial learning and memory, tactile/motor skills, mathematics, a marked disparity in verbal compared to performance IQ (sometimes called a V-P split), and deficits in social and interpersonal relatedness and perception. Children with NLD are often described as kids who “miss the forest for the trees”—they have an excessive focus on details, but often miss the big picture or gestalt.
Defining and Diagnosing NLD
Depending on where and in what context you practice, you may have seen a lot of children who have been given this diagnosis on neuropsychological testing. One of the challenges of understanding NLD is the lack of consensus on what exactly constitutes the syndrome (think pre-DSM psychiatry).
Because of this, there are no clear numbers on prevalence, and much of the research done is marked by significant flaws (Fine JG et al, Child
Neuropsychology 2013;19(2):190-223). Nevertheless, it is a diagnosis that is used more frequently, and which is often useful clinically.
Nonverbal learning disability was first described by Helmer Myklebust in 1975, but is most closely associated with Byron Rourke, who has been the most visible and productive researcher in the field of NLD (see for example Rourke BP, Nonverbal Learning Disabilities: The Syndrome and the Model. The Guilford Press; New York, NY:1989). The term was originally coined to differentiate NLD from the more common language-based learning disabilities such as dyslexia.
NLD is also sometimes called a right hemisphere learning disability, as it is thought to arise predominantly from deficits in this area. Rourke himself has more recently focused on the idea that disturbances in white matter may be connected and causal Rourke BP, The Syndrome of Nonverbal Learning Disabilities. The Guilford Press; New York, NY:1995).
Sorting Through the Controversies
Since researchers have been unable to agree on a definition of NLD, it should not be surprising that many different and contradictory opinions exist on what the most important elements of the disorder are and how it relates to other conditions.
Common controversies include:
• Its relationship to Asperger’s syndrome
• Its persistence over time
• The importance of the V-P split
• The rates of comorbidity with depression and anxiety
• Whether challenges in mathematics are a core feature
The most significant debates revolve around whether social skills deficits are a core part of the disorder, or only present in a subset of individuals.