Literature review of the Clock Drawing Test as a tool for cognitive screening.

BACKGROUND/AIMS The Clock Drawing Test (CDT) is used in clinical practice for the screening of cognitive disorders. This systematic review aims to present and discuss the CDT scoring methods available in the literature, in order to find differences in administration and utility of the CDT. METHODS A literature search was carried out in Medline (1966 to June 2008), Psychinfo (1967 to June 2008) and EMBASE (1980 to June 2008). RESULTS All studies showed good interrater and test-retest reliabilities. The correlation with other standard screening tests was statistically significant in most studies, but the results were influenced by age, education and language. In studies that included patients with mild or questionable dementia, the CDT had a low sensitivity and variable specificity. CONCLUSION The CDT has the characteristics of a good screening method for moderate and severe dementia. However, the scoring method used and potential confounders need to be taken into consideration.