Royall Donald R, Palmer Raymond F, Markides Kyriakos S
Department of Psychiatry, University of Texas Health Science Center, San Antonio.
Audie L. Murphy Division GRECC, South Texas Veterans' Health System, San Antonio.
J Gerontol B Psychol Sci Soc Sci. 2017 Oct 1;72(6):947-955. doi: 10.1093/geronb/gbw004.
The latent variable "δ" has been validated as a dementia phenotype. δ can be extracted from Spearman's general intelligence factor "g" in any data set that contains measures of cognition and instrumental activities of daily living (IADL). We used δ composites ("d-scores") to estimate the prevalence of dementia in the Hispanic Established Population for Epidemiological Studies in the Elderly (H-EPESE).
δ was constructed from Mini-Mental State Examination, a clock-drawing task (CLOX), and IADL. δ's H-EPESE factor weights were validated in the well-characterized Texas Alzheimer's Research and Care Consortium (TARCC). Optimal thresholds for the discrimination between "Alzheimer's disease" (AD) versus normal controls (NCs) were determined by receiver operating characteristic curve. Those thresholds were used to estimate the prevalence of dementia in H-EPESE.
Each δ homolog fits its source's data well. d-scores were strongly associated with Clinical Dementia Rating scale Sum of Boxes (r = .74-.85, all p < .001], and accurately distinguished AD cases from NCs, in both Mexican Americans (MAs) and non-Hispanic Whites (NHWs) [c = 0.94-0.96]. The TARCC MA threshold estimated the prevalence of dementia at 21.4% in H-EPESE. The NHW threshold estimated the prevalence of dementia at 21.0%.
It is possible to export δ composites from populations to well-characterized cohorts for validation.
潜在变量“δ”已被确认为一种痴呆症表型。在任何包含认知和日常生活工具性活动（IADL）测量值的数据集中，δ都可以从斯皮尔曼一般智力因素“g”中提取出来。我们使用δ综合指标（“d分数”）来估计西班牙裔老年人流行病学研究既定人群（H-EPESE）中的痴呆症患病率。
δ由简易精神状态检查表、画钟任务（CLOX）和IADL构建而成。δ在特征明确的德克萨斯州阿尔茨海默病研究与护理联盟（TARCC）中得到了验证。通过受试者工作特征曲线确定“阿尔茨海默病”（AD）与正常对照（NC）之间鉴别的最佳阈值。这些阈值用于估计H-EPESE中的痴呆症患病率。
每个δ同源物都与源数据拟合良好。d分数与临床痴呆评定量表总分密切相关（r = 0.74 - 0.85，所有p < 0.001），并且在墨西哥裔美国人（MAs）和非西班牙裔白人（NHWs）中都能准确区分AD病例与NC（c = 0.94 - 0.96）。TARCC的MA阈值估计H-EPESE中痴呆症的患病率为21.4%。NHW阈值估计痴呆症的患病率为21.0%。
将δ综合指标从人群导出到特征明确的队列中进行验证是可行的。
