Botwinick J, Storandt M, Berg L, Boland S
Department of Psychology, Washington University, St Louis, MO 63130.
Arch Neurol. 1988 May;45(5):493-6. doi: 10.1001/archneur.1988.00520290021007.
There are inherent methodologic problems in investigating senile dementia of the Alzheimer type (SDAT) but this study indicated that, with regard to behavioral test measurement, some of the obvious problems are partially mitigated. First, these data showed that the progressive decline seen in longitudinal SDAT studies is of the same type and magnitude seen in cross-sectional comparisons. Thus, comparing SDAT groups differing in severity provides for the same observations as following up subjects with mild SDAT over time. This study also demonstrates that with certain kinds of tests, selective subject attrition may not be any greater in longitudinal investigations than found in normal aging research. Subjects who dropped out of the longitudinal study were not that different from those who remained in, at least in terms of initial test performance on challenging tests. In this study less than 5% of the subjects with SDAT originally classified as being in the mild stage of the disease remained in this stage after 6 3/4 years of investigation. This inexorable downward path of the subject with SDAT is what appears paramount. Given the similarity of staging in longitudinal and cross-sectional studies, prior test performance levels in the latter studies can be ascertained even if with less accuracy than in longitudinal studies.
在研究阿尔茨海默型老年痴呆症（SDAT）时存在一些固有的方法学问题，但这项研究表明，就行为测试测量而言，一些明显的问题得到了部分缓解。首先，这些数据表明，纵向SDAT研究中观察到的病情逐渐恶化与横断面比较中观察到的情况类型和程度相同。因此，比较病情严重程度不同的SDAT组所得到的观察结果，与对轻度SDAT患者进行长期随访的结果相同。这项研究还表明，对于某些类型的测试，纵向研究中选择性受试者流失可能并不比正常衰老研究中更严重。退出纵向研究的受试者与留在研究中的受试者没有太大差异，至少在具有挑战性测试的初始测试表现方面是这样。在这项研究中，最初被归类为处于疾病轻度阶段的SDAT受试者中，不到5%在经过6又3/4年的研究后仍处于该阶段。SDAT患者这种不可避免的病情恶化趋势似乎是最为重要的。鉴于纵向研究和横断面研究在分期上的相似性，即使准确性不如纵向研究，也可以确定后者研究中先前的测试表现水平。
