What is NLD?
Nonverbal learning disability (NLD or NVLD) is a condition whereby the subject is characterized by a remarkable discrepancy between higher verbal skills and lower motor, visual-spatial, and social skills on an IQ test in conjunction with an assumed right hemisphere brain dysfunction.
The term Nonverbal Learning Disability (NLD or NVLD) describes a relatively newly described condition separate from dyslexia or other forms of learning disabilities. The term has not made it yet into the Diagnosis and Statistical Manual of Mental Disorders (DSM-IV), therefore it is not officially recognized in all of the states and children who have been identified as having NLD may qualify for special education services under the "learning disabilities" or "other health impairments" category included in the Individuals with Disabilities Education Act (IDEA) or under Section 504 of the Rehabilitation Act. At this time, only one state, New Hampshire, appears to recognize nonverbal learning disability as a specific learning disability.
History of NVLD
The discrete subtyping of developmental learning disorders was described by Johnson and Myklebust in1967. Included in the various subtypes were those children who showed distinct deficits in social perception. These children had difficulty interpreting the emotional expression of others, while their language abilities were average to above average.
In the mid 1970s, Byron Rourke began intensive research that continues today to better define the syndrome of NVLD. Rourke’s research has focused on the neuro-psychological profile of children whose deficits produce poor social relatedness. The children he studied had primary deficits in tactile perception, visual perception, complex psychomotor activities and in the ability to process novel material. Secondary deficits (secondary because they were related to the basic deficits) included difficulties in tactile attention, visual attention and exploratory behavior. Tertiary deficits included tactile memory, visual memory, concept formation and problem solving.
Rourke noted when these neuro-psychological deficits interact with strengths in auditory perception, simple motor skills and the ability to process rote material, socio-emotional or adaptational deficits result. Children with NVLD often exhibit extreme difficulty in processing new or complex social situations and interpreting facial expressions. They may rely on well rehearsed or rote behaviors, because they excel in these skills. Social interactions with peers may be stilted and lack reciprocity. The following represents a detailed list of NVLD indicators as described by Rourke.
• Bilateral tactile-perceptual deficits
• Bilateral psychomotor coordination deficits
• Acute deficiencies in visual-spatial-organizational abilities
• Deficits in the areas of nonverbal problem solving, concept formation, hypothesis testing
• Difficulty dealing with negative feedback in novel or complex situations
• Difficulties in dealing with cause-effect relationships
• Difficulties in the appreciation of incongruities
• Well-developed rote verbal capacities and rote verbal memory skills
• Over-reliance on prosaic rote, and consequently inappropriate, behaviors in unfamiliar situations
• Relative deficiencies in mechanical arithmetic as compared to proficiencies in reading (word recognition) and spelling
• Rote and repetitive verbosity
• Content disorders of language
• Poor psycholinguistic pragmatics (cocktail party speech)
• Poor speech prosody
• Reliance on language for social relating, information gathering, and relief from anxiety
• Misspelling almost exclusively of the phonetically accurate variety
• Significant deficits in social perception, social judgment, and social interaction skills
• Marked tendency for social withdrawal and isolation as age increases
High risk for social-emotional disturbance if no appropriate intervention is undertaken (Rourke, B.P. 1995; Rourke, B.P. & Tsatsanis, K.D. 1996). In addition to describing the signs and symptoms of NVLD, Rourke also hypothesized that NVLD is caused by right hemisphere dysfunction and or white matter dysfunction. This neuroanatomical focus was based on previous adult research indicating that the right hemisphere of the brain is responsible for much of the processing of visually based information. Further, adults with destruction of white matter tracts in the brain often have difficulty with visual processing (Rourke, B.P. & Dotto, J.E., 1989; Rourke, B.P. 1995). While Rourke’s contribution to our understanding of NVLD is important, his conception of NVLD as encompassing multiple layers of signs and symptoms culminating in children with significant social skills deficits has been controversial. Another viewpoint is expressed by researchers Martha Denkla and Elsa Shapiro, who have commented that one can have deficits in visual processing without a social skill deficit. Even within the context of a clinical neuropsychological practice, children who meet the diagnostic criteria posited by Rourke are rare.