Esteban-Santillan C, Praditsuwan R, Ueda H, Geldmacher D S
University Alzheimer Center, University Hospitals of Cleveland, Ohio 44120, USA.
J Am Geriatr Soc. 1998 Oct;46(10):1266-9. doi: 10.1111/j.1532-5415.1998.tb04543.x.
The primary objective of this study was to determine the efficacy of the clock drawing test to predict the presence of very mild Alzheimer's disease (AD). A secondary objective was to identify elements of clock drawing that were most useful in differentiating cognitively intact older adults from those with mild Alzheimer's disease.
Cohort based comparison of retrospective data.
Academic research center.
Clock drawings from 41 outpatient cases of mild AD with Mini-Mental State Exam scores of 24 or higher and 39 age- and education-matched older adults were scored.
Clock drawings were blindly and independently scored by two raters using the Clock Drawing Interpretation Scale and the scoring system reported by Rouleau et al. Predictive values for positive and negative tests were calculated using cut-off scores for total score and component subscores from each of these two systems.
Two or more errors in the depiction of the clock hands on the Clock Drawing Interpretation Scale had a positive predictive value for AD of 100% and a negative predictive value of 51%. A score of 2 or less on the 4-point hand-placement component of the Rouleau et al. scoring system provided a positive predictive value for AD of 94% and was associated with a negative predictive value of 62%.
An individual who commits two errors or more in drawing the clock hands deserves further investigation for a possible dementia. Normal hand placement on the clock drawing test does not exclude AD. However, when prevalence rates of dementia in community-dwelling older adults are considered, these results argue that normal clock hand placement indicates that dementia is unlikely.
本研究的主要目的是确定画钟试验预测极轻度阿尔茨海默病（AD）存在的有效性。次要目的是确定画钟的哪些元素最有助于区分认知功能正常的老年人和轻度阿尔茨海默病患者。
基于队列的回顾性数据比较。
学术研究中心。
对41例轻度AD门诊患者（简易精神状态检查表得分24分或更高）以及39名年龄和教育程度匹配的老年人的画钟进行评分。
两名评分者使用画钟解释量表和Rouleau等人报告的评分系统对画钟进行盲法独立评分。使用这两个系统中总分和各分量表分数的临界值计算阳性和阴性试验的预测值。
在画钟解释量表上，时针描绘出现两个或更多错误对AD的阳性预测值为100%，阴性预测值为51%。在Rouleau等人的评分系统中，4分制的指针放置分量表得分为2分或更低时，对AD的阳性预测值为94%，阴性预测值为62%。
在画时针时出现两个或更多错误的个体值得进一步检查是否可能患有痴呆症。画钟试验中指针放置正常并不能排除AD。然而，考虑到社区居住老年人中痴呆症的患病率，这些结果表明指针放置正常表明痴呆症不太可能。
