Assessment of cognitive decline associated with aging: a comparison of individuals with Down syndrome and other etiologies.

Cognitive processes and their decline with aging were studied in individuals with Down Syndrome (DS) and individuals of comparable mental handicap without Down Syndrome (NonDS). The cognitive processes were measured by tests of Planning, Attention, Simultaneous, and Successive processing. The DS and NonDS samples were divided into age groups of 26-40 years (DS = 23, NonDS = 23) and 41-60 years (DS = 8, NonDS = 18). Analyses of variance using factor scores demonstrated articulation to be significantly poorer in the DS sample at and above 40 years. Specifically, the tests that showed the interaction effects between DS/NonDS and the two age groups were Number Finding, Expressive Attention, and Speech Rate. When the cutoff age was raised to 50 years, an additional Attention and Planning task (Receptive Attention and Matching Numbers) also showed the interaction effect. These tests hold the promise for diagnosing early signs of dementia of Alzheimer type. Implications for rehabilitation are described.