The Clock Drawing Test A review of its accuracy in screening for dementia

Abstract

The Clock Drawing Test (CDT) is a simple neuropsychometric instrument that can be easily applied to assess several cognitive functions. Over the past 20 years, the CDT has aroused considerable interest in its role for the early screening of cognitive impairment, especially in dementia. Although the CDT is considered an accurate test for dementia screening, recent studies including comparisons with structured batteries such as the CAMCOG have shown mixed results.ObjectivesTo investigate the importance of the CDT compared to other commonly used tests, in the diagnosis of dementia in the elderly; (2) to evaluate the reliability and correlation between available CDT scoring scales from recent studies.MethodsA systematic search in the literature was conducted in September 2008 for studies comparing CDT scoring systems and comparing the CDT with neuropsychiatric batteries.ResultsTwelve studies were selected for analyses. Seven of these studies compared CDT scoring scales while five compared the CDT against the CAMCOG and the MMSE. Eight studies found good correlation and reliability between the scales and the other tests.ConclusionDespite the mixed results in these studies, the CDT appears to be a good screening test for dementia.

Italian norms for the Freedman version of the Clock Drawing Test

“…As the validity of CDT in the screening of dementia has been demonstrated already (Aprahamian et al, 2009;Shulman, 2000), the availability of standardized norms for this instrument should increase its use in the assessment of patients with mild cognitive impairment and Alzheimer's disease. The computation of equivalent scores has the advantages of allowing a more direct comparison of performance on this test with that on other tests that have also been standardized using similar methods.…”

“…Visuospatial errors were mainly related to right hemisphere damage, whereas errors in time setting were mostly caused by left hemisphere lesions (Tranel et al, 2008). Currently, the CDT is considered a good screening tool for dementia (Aprahamian, Martinelli, Liberalesso Neri, & Sanches Yassuda, 2009). CDT has high levels of sensitivity and a specificity level of approximately 85% and, together with the Mini-Mental State Examination (MMSE; Folstein, Anthony, Parhad, Duffy, & Gruenberg, 1985), can improve the detection of dementia (Cahn et al, 1996).…”

Testing Older Adults for Signs of Age-Related Cognitive Decline: Clock Drawing Test vs.Mini-Mental State Examination

“…In 1986, Shulman and his colleagues published the first study associating CDT with the screening of elderly patients with cognitive disorders. Although CDT is a specific indicator of executive functions, the test assesses many cognitive skills that may be involved in early stage of Alzheimer disease, such as short-term memory, spatial orientation, abstract thinking, planning, concentration, executive and visuospatial skills (Aprahamian, Martinelli, Neri, & Yassuda, 2009). …”

Suggested instruments for General Practitioners in countries with low schooling to screen for cognitive impairment in the elderly

“…It is likely that the efficacy of the delayed recall in discriminating CIND from WCI is not as high as for dementia thus explaining the lower sensitivity and specificity seen in the present study. The accuracy of the Clock Drawing Test for CI screening has been previously evaluated (Aprahamian et al, 2009) and shown to be effective for discriminating dementia, but less effective for mild cases of dementia or CIND from normal individuals and that might be the reason for the low specificity of the CDT found in our study when used alone, what was expected since CDT is a test mostly influenced by schooling. The combination of the CDT and FAQ showed the highest accuracy for distinguishing both dementia and CIND from WCI in our study, although the utility of the CDT in populations with lower schooling is well-known.…”