Sliwinski M, Lipton R B, Buschke H, Stewart W
Saul R. Korey Department of Neurology, Albert Einstein College of Medicine, USA.
J Gerontol B Psychol Sci Soc Sci. 1996 Jul;51(4):P217-25. doi: 10.1093/geronb/51b.4.p217.
Individuals with preclinical dementia have begun to decline cognitively, but still perform within normal limits on cognitive testing. As a group, subjects with preclinical dementia have lower scores on neuropsychological tests than their dementia-free counterparts. This study examines the effects of preclinical dementia on estimates of normal cognitive function in the aged using data from a longitudinal study. Individuals with preclinical dementia at baseline were retrospectively identified based on subsequent development of dementia. Age-adjusted norms were computed using baseline data for the Selective Reminding Test and the WAIS verbal and performance scores, both including (conventional norms) and then excluding (robust norms) preclinical cases. The results indicate that by failing to exclude preclinical dementia, conventional normative studies underestimate the mean, overestimate the variance, and overestimate the effect of age on cognitive measures. Methods are discussed for selecting robust elderly samples that are relatively free of contamination by preclinical dementia.
处于临床前痴呆阶段的个体认知功能已开始衰退，但在认知测试中仍表现正常。作为一个群体，临床前痴呆患者在神经心理学测试中的得分低于未患痴呆的同龄人。本研究利用一项纵向研究的数据，考察了临床前痴呆对老年人正常认知功能评估的影响。根据随后痴呆的发展情况，回顾性地确定了基线时处于临床前痴呆阶段的个体。使用选择性提醒测试的基线数据以及韦氏成人智力量表的言语和操作得分计算年龄调整后的常模，计算时既包括（传统常模）也排除（稳健常模）临床前病例。结果表明，由于未排除临床前痴呆，传统的常模研究低估了均值，高估了方差，且高估了年龄对认知测量的影响。文中讨论了选择相对未受临床前痴呆影响的稳健老年样本的方法。
