Fitten L J, Lusky R, Hamann C
Department of Psychiatry, University of California, Los Angeles School of Medicine.
J Am Geriatr Soc. 1990 Oct;38(10):1097-104. doi: 10.1111/j.1532-5415.1990.tb01372.x.
Clinicians usually employ indirect measures of cognitive and physical function in order to assess medical decision-making capacity. We tested a reference group of well elderly (Mini-Mental State Exam [MMSE] score = 29.1 +/- 0.8, mean +/- SD), for their understanding of three increasingly complex, hypothetical treatment situations or "vignettes"--use of a hypnotic, need for thoracocentesis, and desire for CPR. From this, we have developed a more direct, Guttman-like assessment of decision-making capacity. Of 51 Veterans Affairs nursing home residents (MMSE score = 22.4 +/- 6.9), only 33.3% demonstrated intact decision-making capacity by this method, whereas 77% were felt by their primary physicians to be capable of giving consent for oral surgery; 37.3% had very impaired decision-making capacity; and 29.4% were intermediate in this ability. Judged against our more direct assessment of decision-making capacity, primary physicians' judgment of capacity for consent was 31% to 39% sensitive in identifying impaired decision-making and the MMSE was 53% to 63% sensitive. These measures were 100% and 82% to 83% specific in identifying intact decision-making capacity, respectively. We conclude that (1) more directly assessed decision-making capacity varies noticeably among elderly nursing home residents and correlates in only limited fashion with frequently used cognitive screening methods; and (2) cognitive screening tests underestimate the prevalence of impaired decision-making capacity in this population. For informed consent and advance directives, our study suggests that decision-making capacity should be directly, rather than indirectly, assessed.
临床医生通常采用认知和身体功能的间接测量方法来评估医疗决策能力。我们测试了一组健康老年人（简易精神状态检查表[MMSE]评分 = 29.1±0.8，均值±标准差），以了解他们对三种日益复杂的假设治疗情况或“案例”的理解——使用催眠药、胸腔穿刺术的必要性以及心肺复苏的意愿。据此，我们开发了一种更直接的、类似古特曼量表的决策能力评估方法。在51名退伍军人事务疗养院居民中（MMSE评分 = 22.4±6.9），通过这种方法只有33.3%的人表现出完整的决策能力，而其主治医生认为77%的人有能力同意接受口腔手术；37.3%的人决策能力严重受损；29.4%的人处于中等水平。与我们对决策能力的更直接评估相比，主治医生对同意能力的判断在识别受损决策能力方面的敏感性为31%至39%，MMSE的敏感性为53%至63%。这些测量方法在识别完整决策能力方面的特异性分别为100%和82%至83%。我们得出结论：（1）在老年疗养院居民中，经更直接评估的决策能力存在显著差异，且与常用的认知筛查方法仅有有限的相关性；（2）认知筛查测试低估了该人群中受损决策能力的患病率。对于知情同意和预先指示，我们的研究表明，决策能力应直接而非间接评估。
