Interrelationships of biological environmental and competency variables in young children with Down syndrome.

Abstract

Eighty-nine children with Down syndrome were followed longitudinally from birth to 36 months by an interdisciplinary team of professionals. Means and standard deviations of measures on the Bayley Scales of Infant Development and the Vineland Social Maturity Scale indicate that the average child with Down syndrome functions at the lower end of the mildly retarded range, while the language development is more delayed. Evaluation of correlation coefficients for the same scales revealed the correlations to increase with advancing age, while the correlations between different tests are of a more complex nature. In subsequent analyses we focused on developmental interrelationships, major influencing factors of specified functions, and predictable outcome competencies. Certain behavioral variables were identified by principal component analysis using varimax rotation. Through subsequent path analysis it was found that the presence of significant congenital heart disease influences adversely the muscle tone and the parents' ability to follow-through with the provided guidance. Muscle tone in turn is a powerful predictor of all the outcome variables including language acquisition, motor and social development, and mental functioning. The general development at six months was noted to influence future language acquisition as well as mental development in subsequent years. The ability to follow through is affected by muscle tone and by the parents' ability to cope. In turn, follow-through had a significant influence on mental development between 12 and 36 months.