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 of developing 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 it 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 neuropsychological testing: individuals without MCI and individuals with MCI. The CDT scores, evaluated by the scoring system of Sunderland et al. [J Am Geriatr Soc 1989;37:725-729], of both groups were compared. Multivariate analyses were calculated and the sensitivity and 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 receiver operating characteristic analyses are not adequate, meaning that the 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 does not achieve the quality to screen individuals for MCI.