Abstract

Developmental dyscalculia (DD) is a number processing and calculation disorder that has been identified in a similar fashion to other specific learning disorders. That is, the diagnosis is made when the individual’s achievement or ability in arithmetic is significantly below that expected for age, schooling, and level of intelligence. This disorder is conceptualized as a hereditary disorder, being present from early childhood, and is not the result of poor or inappropriate schooling, cultural factors or medical conditions (American Psychiatric Association, 2000; WHO, 1996), although these latter conditions can aggravate any learning disability. Although this widely accepted definition appears plausible, findings from recent years require reconsideration firstly of the way DD is defined and secondly of diagnostic criteria.