Numerical and arithmetical cognition: Patterns of functions and deficits in children at risk for a mathematical disability

Based on performance on standard achievement tests, first-grade children (m ean age = 82 months) with IQ scores in the low-average to high-average rang e were classified as at risk for a learning disability (LD) in mathematics, reading, or both. These at-risk children (n = 55) and a control group of a cademically normal peers (n = 35) were administered experimental tasks that assessed number comprehension and production skills, counting knowledge, a rithmetic skills, working memory, and ease of retrieving information from l ong-term memory. Different patterns of intact cognitive functions and defic its were found for children in the different at-risk groups. As a set, perf ormance on the experimental tasks accounted for roughly 50% and 10% of the group differences in mathematics and reading achievement, respectively, abo ve and beyond the influence of IQ. Performance on the experimental tasks th us provides insights into the cognitive deficits underlying different forms of LD, as well as into the sources of individual differences in academic a chievement, (C) 1999 Academic Press.