Impact of motor skills on cognitive test results in very-low-birthweight children.

Standardized tests that are frequently used to evaluate the cognitive development of very-low-birthweight children often appear to measure motor ability as well as cognitive skills. To estimate the impact of motor skills on individual test performance among very-low-birthweight children of kindergarten age, we employed factor analysis in a sample of 298 very-low-birthweight children that included severely disabled children. Using a test battery designed to measure concentration, language skills, overall cognitive development, visuomotor abilities, and memory, we identified two factors in each of three diagnostic subgroups: unimpaired children (n = 184), clumsy children (n = 56), and children with cerebral palsy (n = 33). Based on the pattern of factor loadings, we interpret the first factor as capturing language and overall cognitive abilities, whereas the second factor appears to capture motor abilities. Language skills explained 49% and motor abilities accounted for 16% of the overall variance of the individual test results. Among children with attention deficit (n = 25), a third factor emerged. In these children, we interpret the first factor as capturing language or cognitive skills, the second as representing visuomotor skills, and the third as a quantifier of the ability to concentrate. The test battery tested the same abilities in impaired and unimpaired children; however, these were not always the abilities that the battery aimed to test. Future studies need to evaluate whether factor scores only for cognitive but not motor abilities might be useful outcome variables.