Visual Attention/Perception and APOE Risk for AD

描述：（改编自申请人的摘要）：阿尔茨海默病（AD）是 以认知功能的逐渐丧失为特征。研究 载脂蛋白E（APOE）基因型表明，c4的存在， 等位基因显著增加了AD的发病风险， 甚至在临床症状发作之前， 症状我们提出了一种新的方法来检测AD的早期影响 在具有E4等位基因的遗传风险增加的个体中， 使用计算机化任务作为认知“压力测试”的临床症状， 系统地改变注意力负荷和知觉困难。通过增加 在实验控制的环境中， 以这种方式，我们假设AD遗传风险的队列差异可能是 通过信息处理速度的变化来检测， 任务表现的差异可能与大脑的变化有关， 以前在这些非痴呆的健康人中用神经成像技术观察到的， 科目在这项研究中，25例e4纯合子，25例c4杂合子，25例s4 年龄、性别和教育水平相匹配的非携带者将被 包括.这些受试者将是健康志愿者，年龄50 - 65岁，报告 阿尔茨海默氏痴呆症的家族史，并参与了一个单独的 AD风险增加的神经影像学效应的纵向研究 E4等位基因信息处理方法将被用来测试他们的 认知功能在两个实验：1）与视觉注意任务， 实验性地改变与目标相关的干扰物的数量，以及2）使用 面部匹配任务，其中感知难度逐渐增加。 分析将测试组在执行任务方面的差异， 将任务表现的差异与大脑代谢模式联系起来， 使用从这些受试者中获得的神经成像结果， 独立纵向研究。确定在何种条件下， 这种认知任务发生在有AD风险的人中， 检测，以了解认知功能障碍的机制， 评估AD的预防治疗。

DESCRIPTION:(adapted from applicant's abstract): Alzheimer's disease (AD) is characterized by a progressive loss of cognitive functions. Studies of apolipoprotein E (APOE) genotype have suggested that the presence of the c4 allele substantially increases the risk for developing AD and is associated with reductions in cerebral metabolism even prior to the onset of clinical symptoms. We propose a new approach for detecting the very early effects of AD in individuals with increased genetic risk with the e4 allele, but without clinical symptoms using computerized tasks as cognitive "stress tests" that systematically vary attentional load and perceptual difficulty. By increasing the attentional or perceptual demands of a task in an experimentally controlled manner, we hypothesize that cohort differences in genetic risk for AD may be detected through alterations in speed of information processing and that differences in task performance may be related to brain changes that have been previously observed with neuroimaging techniques in these non-demented, healthy subjects. In this study, 25 e4 homozygotes, 25 c4 heterozygotes, and 25 s4 non-carriers who are matched in age, gender, and educational level will be included. These subjects will be healthy volunteers, ages 50 - 65, who report a family history of Alzheimer's dementia and are participants in a separate longitudinal study of the neuroimaging effects of increased risk for AD with the E4 allele. An information-processing approach will be used to test their cognitive function in two experiments: 1) with visual attention tasks that experimentally vary the number of target-relevant distractors and 2) using a face-matching task in which perceptual difficulty is incrementally increased. Analyses will test group differences in performing the tasks and will relate subject differences in task performance to patterns of brain metabolism and atrophy using neuroimaging results obtained for these subjects from the separate longitudinal study. Determining under what conditions differences in such cognitive tasks occur in persons at risk for AD may aid efforts for early detection, for understanding the mechanism of cognitive dysfunction, and for evaluating prevention therapies in AD.