P2-113: The utility of the clock drawing test for cognitive impairment screening

Abstract

Because of improved symptomatic treatment options for dementia, early detection is an important issue. Therefore, a simple and quickly administered test at low cost is needed. The clock drawing test (CDT) provides a simple and reliable measure of a comprehensive range of cognitive functions. To examine the usefulness of the CDT when used as a cognitive screening instrument for dementia, and to compare different scoring methods of CDT, and to check the correlations with the Mini–Mental State Examination (MMSE) score and Hasegawa Dementia Scale (HDS). We reviewed the charts of the 37 patients with memory complaints, visiting the outpatient clinic between January 2005 and July 2005, of which 20 patients were diagnosed with the Alzheimer's dementia, 10 with vascular dementia, and 7 with mild cognitive impairment. The patients had all undergone the Korean version of the MMSE and the Korean version of revised form of HDS. For the CDT, each patient was given a blank paper and asked to draw a clock face with all numbers on it and then draw hands on the clock to make it read 2:40. The CDT was scored by 5 different scoring methods (Sunderland, modified Shulman, Rouleau, Cahn, simplified Freedman's methods). The patients were 25 women and 12 men; their mean age was 73.59 years (±6.94) (range 56 – 92). The mean MMSE score was 19.54±4.45, and the mean HDS score was 17.22±5.36. The MMSE score was significantly correlated with all methods of scoring the CDT (r= 0.672∼0.728, p <0.01), the Sunderland scoring method producing the highest correlation. Similarly, all five scoring methods correlated significantly with the HDS score (r= 0.406∼0.494), less than the MMSE score. All correlations between CDT scoring methods were statistically significant (r= 0.93∼0.98, p<0.01). Deterioration in the CDT score correlates with severity of global cognitive impairment, as assessed by the MMSE and HDS. Therefore the CDT can be used as useful cognitive impairment screening, either by itself or as a part of a brief neuropsychological test battery.