Arithmetic disabilities, specific and otherwise: a neuropsychological perspective.

From a neuropsychological perspective, this article summarizes research that addresses some of the developmental interactions of disabilities in reading, spelling, and mechanical arithmetic. The focus is on two subtypes of children with learning disabilities who exhibit equally impaired levels of arithmetic achievement, but with vastly different patterns of neuropsychological assets and deficits. Qualitative as well as quantitative analyses lead to the conclusion that one of these patterns of neuropsychological assets and deficits (i.e., the nonverbal learning disabilities syndrome; NLD) leads--at the same time and in much the same manner--to specific patterns of impairment in mechanical arithmetic and in psychosocial functioning. The other pattern (Group R-S) is found to lead to particular patterns of academic deficits (including arithmetic), but not to any particular level or type of psychosocial dysfunction. The manifestations of the NLD profile in various types of neurological disease, disorder, and dysfunction are also explored.