A reduced scoring system for the Clock-Drawing Test using a population-based sample




Jouk, Alexandra

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This thesis project examined the generalizabilty of the simplified scoring system for the Clock Drawing Test developed by Lessig and her colleagues in 2008 using a population-based sample. Clock-drawings from 356 participants (80 with dementia, 276 healthy controls) from the Canadian Study on Health and Aging were analyzed using logistic regression and Receiver Operating Characteristic curves. The new scoring system reduced the Lessig system down even further to include five critical errors: missing numbers, repeated numbers, number orientation, extra marks, and number distance, and produced a sensitivity of 81% and a specificity of 68%. The results from this study improve our current state of knowledge concerning the Clock Drawing Task by validating the simplified scoring system proposed by Lessig and her colleagues among a more representative sample and provides further evidence in support of a simple and reliable dementia-screening tool.



Clock-Drawing Test, Dementia, Scoring system