Effects of age on the adaptive behavior of institutionalized and noninstitutionalized individuals with Down syndrome.

The effects of age on the adaptive behavior of individuals with Down syndrome and matched individuals in other diagnostic categories were compared in three studies. The only study that provided evidence of a decline in competence among older individuals with Down syndrome was the one study in which the oldest age category was 60 years and over. In that study, a significant Age X Diagnosis interaction was found for the Motor Development factor of the Client Development Evaluation Report, reflecting a sharp drop in the scores of some of the oldest subjects with Down syndrome. These results resemble those of other recent research in two respects: the age at which the decline in competence occurred and the nature of that decline.