Qualitative Features of Clock Drawings in Normal Aging and Alzheimer's Disease

Two investigations examined qualitative features of clock drawings in normal aging and Alzheimer's disease (AD), using standard 3-point and 10-point scales and an expanded 16-point scoring system. In the first study, clock drawings by healthy adults aged 50-70 were found to be significantly better than those of adults aged 70-95 using all three scoring systems. Results based on the 16-point system were strongly associated with those of other scoring systems, but correlations with two other visuospatial measures were low. Older adults demonstrated more difficulty in terms of numerical position, time-setting, and addition of irrelevant details. In Study II, using the same scoring systems, AD patients were significantly impaired on clock drawings compared to matched controls. AD patients showed particular deficits in the following domains: numerical position, time setting, proportions, spatial accuracy, and omission of details. The 16-point clock scoring system was equivalent to other scoring procedures in differentiating groups and showed modest reliability coefficients. Results suggest that alterations in visuospatial relations in aging and dementia share some features with conceptual declines in the two groups, although there are qualitative differences that may be of utility in understanding the underlying processes involved in aging and dementia.