Developmental changes of institutionalized mentally retarded children: a semilongitudinal study.

Developmental Record ratings were obtained for 200 institutionalized mentally retarded children over a 3-year period. Following a principal components analysis to determine the most appropriate form of inputting data, we obtained semilongitudinal developmental curves for children at each of four levels of retardation and for boys and girls separately. Results indicated that differences in measured intelligence are associated with differences in various kinds of developmental behavior and that between the ages of 7 and 20 years the relationship is primarily a linear one. When subjects were divided according to sex instead of level of retardation, differences appeared to be minimal. These results should be helpful in predicting later attainments of institutionalized retarded children since ratings on the Developmental Record can be translated into specific types of developmental behavior.