The Framingham Heart Study clock drawing performance: normative data from the offspring cohort

BACKGROUND/STUDY CONTEXT: Although the Clock Drawing Test (CDT) is a popular tool used to assess cognitive function, limited normative data on CDT performance exist. The objective of the current study was to provide normative data on an expanded version of previous CDT scoring protocols from a large community-based sample of middle to older adults (aged 43 to 91) from the Framingham Heart Study.

The CDT was administered to 1476 Framingham Heart Study Offspring Cohort participants using a scoring protocol that assigned error scores to drawn features. Total error scores were computed, as well as for subscales pertaining to outline, numeral placement, time-setting, center, and "other."

Higher levels of education were significantly associated with fewer errors for time-setting (Command: p < .001; Copy: p = .003), numerals (Command: p < .001), and "other" (Command: p < .001) subscales. Older age was significantly associated with more errors for time-setting (Command: p < .001; Copy: p = .003), numerals (Command: p < .001), and "other" (Command: p < .001) subscales. Significant differences were also found between education groups on the Command condition for all but the oldest age group (75+).

Results provide normative data on CDT performance within a community-based cohort. Errors appear to be more prevalent in older compared with younger individuals, and may be less prevalent in individuals who completed at least some college compared with those who did not. Future studies are needed to determine whether this expanded scoring system allows detection of preclinical symptoms of future risk for dementia.