[Cognitive function screening of community-dwelling elderly people using the clock drawing test -quantitative and qualitative analyses].

AIM: The purpose of this study was to evaluate whether the clock drawing test (CDT) is useful to assess the cognitive function of community-dwelling elderly people. We evaluated the CDT as a tool to measure cognitive function by qualitative and quantitative analyses. METHODS: A total of 14,949 community-dwelling elderly were invited by mail to undergo cognitive screening by CDT. Of these, 8,815 responded, of which 8,684 were eligible for enrollment. We were also able to determine the educational background of 7,404 of these. There were 3,525 men (age: 73.05±6.20 [mean±standard deviation] years old, duration of education: 11.40±2.81 years) and 3,879 women (73.67±6.66, 10.34±2.19) . The drawn clocks were evaluated using the Freedman method, and those clocks drawn with obvious errors such as no circle, numbers, or hands were recorded and analyzed. In addition, any vertical deviation from the center points was also evaluated. RESULTS: The recorded percentages of the subjects who correctly completed the individual clock drawing test components varied. The mean total scores were 14.16±1.67 in men and 14.40±1.36 in women. The percentages of subjects with total scores of less than 13 were 16.09% in men and 11.7% in women. The percentage of subjects who made obvious errors was 3.24%, whose total points were significantly lower than those of the subjects who did not. Approximately half of all subjects showed vertical deviation from the center of the clock, and the percentage of upper deviation was greater than that of lower deviation. CONCLUSION: CDT is useful to assess the cognitive function of community-dwelling elderly people, and it is also helpful to determine subjects with a potential risk of cognitive impairments.