Nonverbal learning disability.

Nonverbal learning disability (NLD) is described as a subtype of specific learning disability where the source of the disability is a difficulty in processing nonverbal information. The child with NLD presents with problems in visual, spatial, and tactile perception but with strengths in rote verbal skills. Traditionally, these children were recognized by their difficulties in arithmetic which presented a stark contrast with their strengths in spelling and decoding text. They also exhibited a split between their verbal IQ (VIQ) and performance IQ (PIQ) scores with the VIQ being significantly higher than PIQ. Over time, however, diagnostic criteria have evolved and the broadened definition of the NLD syndrome has led many to question the utility and uniqueness of the NLD diagnosis. In addition, shifting diagnostic standards have made research results difficult to replicate. In short, the research to date leaves many unanswered questions about (1) the definition of the NLD syndrome, (2) the pervasiveness of the academic, social and psychopathological difficulties, (3) the source of the NLD syndrome, and (4) the degree to which it overlaps with other conditions. This chapter outlines a brief history of the NLD syndrome, how it is currently conceptualized, and some of the current debate about the unanswered questions above.