Is the Clock Drawing Test appropriate for screening for Mild Cognitive Impairment? Results of the German Study on Ageing, Cognition and Dementia in Primary Care Patients (AgeCoDe)

Background: Individuals with Mild Cognitive Impairment (MCI) are at high risk to develop dementia and are a target group for preventive interventions. Therefore, research aims at diagnosing MCI at an early stage with short, simple and easily administrable screening tests. Due to the fact that the Clock Drawing Test (CDT) is widely used to screen for dementia, it is questionable whether the CDT is suited to screen for MCI. Methods: 3,198 primary care patients aged 75+ were divided into two groups according to their cognitive status, assessed by comprehensive neuro-psychological testing: individuals without MCI and individuals with MCI. The CDT-scores, evaluated by the scoring system of Sunderland et al. (1989), of both groups were compared. Multivariate analyses were calculated as well as sensitivity, and the specificity of the CDT to screen for MCI were reported. Results: Significant differences were found for CDT-results: MCI-patients obtained worse results than cognitively unimpaired subjects. CDT has a significant impact on the diagnosis of MCI. However, sensitivity and specificity as well as ROC analyses are not adequate, meaning CDT could not be named as an exact screening tool. Limitations: Applying different CDT-versions of administration and scoring could yield different results. Conclusions: CDT did not achieve the quality to screen individuals for MCI.