All of a sudden, it seems that everyone is talking about something called "non-verbal learning disability" or NLD. Speech-language pathologists receive referrals where NLD is listed as the diagnosis. Psychologists and teachers discuss NLD at coffee and at team meetings. For many SLPs, this is an unfamiliar diagnostic term, and its use raises several questions. Clinicians ask: What is nonverbal learning disability? What causes it? How do I recognize it? If it's nonverbal, what does it have to do with me? Is there a communication problem? How should I assess these children? What do I do about it? Unfortunately, since research has lagged behind the rapid rise in popularity of this diagnostic category, definitive answers to these questions are in short supply, but this article is an attempt to provide at least partial answers to some of them.

What Is NLD and What's It Have to Do With Me?

NLD is a subtype of learning disability that has been the subject of intense scrutiny by Byron Rourke, a neuropsychologist at the University of Windsor. He and his colleagues (see references) have identified two reliable subtypes of learning disability. They call one group Basic Phonological Processing Disorder. Children in this category fit well within our traditional views of language learning disability or specific language impairment. These are children who are characterized by poor speech and language skills and extraordinary difficulty with reading and writing, but who demonstrate relatively preserved nonverbal problem solving. Generally, their performance IQ is within normal limits, but verbal IQ scores are significantly depressed.

Rourke calls the other group Nonverbal Learning Disability. Children placed in this group display a profile of skills that is largely opposite from the first group. Verbal IQ scores, for example, are well within normal limits, whereas nonverbal IQ lags behind. These children have difficulty with nonverbal problem solving, visual-spatial-organizational skills, tactile perception, and complex psychomotor behavior but, on the surface at least, they appear to have good language skills. They talk (often excessively), they use a variety of sentence structures, they can memorize and repeat vast amounts of verbal material, and they demonstrate average to above-average abilities in single-word reading and spelling.

At first glance, it may seem that SLPs have no role to play in the management of these children. Despite their verbal fluency, however, children and adolescents with NLD exhibit substantial communication and language problems. The key to understanding their communication dysfunction is that their apparent competence in language is superficial. Whenever situations call for deep or elaborated comprehension, use of contextual information, or sophisticated social competence, children with NLD are likely to perform poorly, demonstrating just how shallow their abilities are.

Causes

According to Rourke, NLD manifests itself to some degree whenever significant amounts of white matter in the brain are destroyed or dysfunctional. Specifically, he proposes that damage to the white matter in the right cerebral hemisphere is particularly influential. As plausible as this model may be, it is far from definitive. Other authors have suggested that the symptoms...