We all agree that learning disabilities are not a single thing but rather a group of disorders that can affect a person's ability to receive, process, store and respond to information. We also agree that these seemingly unexplained difficulties occur in persons of at least average intelligence and that these difficulties cannot be explained by health, cultural, environmental or economic factors. And let's not forget that many individuals with LD experience significant struggle with non-academic learning and behavior, an often overlooked feature of LD that was mentioned by Dr. Samuel Kirk more than three decades ago when he spoke about children with LD who had trouble with "skills needed for social interaction."
So what exactly do we mean by the term nonverbal learning disabilities (NVLD)? There is no simple answer
Verbal vs. Non-verbal LD
At the risk of oversimplification, let's group learning disabilities into two distinct types:
- language-based LD: This is characterized by poor speech and/or language skills, difficulties with vocabulary and speed/accuracy of performance on language-related tasks, and overall problems with reading and writing.
- non-verbal LD: This points to great difficulties with problem solving that do not involve written or spoken language. It also points to struggles staying organized in terms of time and space, while having (at least on the surface) good language skills.
And let's add in a few typical (or frequently reported) characteristics to the non-verbal LD list
- a tendency to talk (often excessively), using age-appropriate and even advanced sentence structures,
- an uncanny ability to read and spell single words (with performance deteriorating on extended narratives), and
- a predisposition to memorize and repeat large amounts of verbal information, but a pronounced weakness in knowing how and when to share this knowledge in socially appropriate ways.
Thinking about the clusters of strengths and weaknesses that typify non-verbal learning disabilities, it is apparent how individuals with NVLD pose unique challenges to parents and educators. Adding to the challenge is the fact that the features of NVLD, more than in other subtypes of LD or categories of disability, change (for the worse!) as a child gets older. For example, a first grader with NVLD may demonstrate very strong verbal skills ('a little professor') and be expected to know how to apply these skills to promote school success. Over time, given weaknesses in such areas as organization, abstract thinking and social cueing, in conjunction with apparent early strengths in isolated skill areas, this same student might quickly fall behind and be perceived as not trying hard enough.
A Diagnostic Dilemma
Just like there is no single profile of learning disabilities in general, there is also no single profile for individuals whose challenges fall into these verbal and non-verbal domains. Not only does the menu of challenges experienced by those with LD frequently overlap between these categories, but it can also include features of other disability categories such a Expressive and Receptive Language Disorders, Asperger's Syndrome, Pervasive Developmental Disorder (PDD), and Attention-Deficit/Hyperactivity Disorder (ADHD). This is especially true for NVLD, with some researchers and clinicians even hypothesizing that NVLD is a mild form of Asperger's Syndrome.
At this time there is no real consensus about the prevalence of NVLD or even about a definition for this subtype of LD. What we do know is that non-verbal learning disabilities can be hard to recognize and pinpoint, and as a result, the challenges faced by some individuals with this disorder are going to be attributed to other disorders or educational classifications such as autism and emotional disturbance. Clinicians who work with NVLD often report that these individuals are at increased risk for developing emotional and social adjustment problems and that NVLD is often associated with having fewer friends, being overly dependent upon parents, and being prone to problems such as obsessive-compulsive disorder or depression.