Understanding visual working memory in Alzheimer's disease

了解阿尔茨海默病的视觉工作记忆

• 批准号: 8453991
• 负责人: Philip Ko
• 金额: $ 5.58万
• 依托单位: VANDERBILT UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-12-01 至 2015-11-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8453991
• 关键词: Activities of Daily Living; Affect; Alzheimer' s Disease; Attention; Attentional deficit; Automobile Driving; Basic Science; Behavioral; Binding; Caregivers; Cognitive; Complex; Detection; Disorientation; Elderly; Electroencephalogram; Environment; Event-Related Potentials; Family; Healthcare Systems; Impairment; Independent Living; Lead; Life; Maintenance; Measures; Mediating; Memory; Memory impairment; Methods; Mind; Patients; Perception; Pharmaceutical Preparations; Phase; Process; Quality of life; Research; Short-Term Memory; Source; Staging; Testing; Variant; Visual; Visual attention; Work; base; daily functioning; functional decline; improved; long term memory; memory encoding; mental representation; pill; rehearsal; relating to nervous system; research study; visual cognition; visual information; visual process; visual processing

DESCRIPTION (provided by applicant): Recent work has shown that patients with Alzheimer's disease (AD) have a normal visual working memory (VWM) capacity for simple visual features when compared to healthy older adults. In contrast, AD patients have reduced VWM capacity for complex objects, resulting from an impaired ability to bind the visual features of complex objects together. Understanding the cognitive and neural basis underlying this binding impairment is critical because VWM is vitally important for basic visual tasks, such as navigating new environments, noting changes in the landscape, finding objects in a cluttered space, and driving. Decades of previous research have indicated that VWM is a complex process that can be divided into several processing stages. These include an early stage of encoding that creates a mental representation of previously viewed information and a later stage of maintenance that stores the representation without requiring external stimulation. Multiple factors mediate each of these stages, including those involving perception, attention, and memory. Importantly, a deficit of attention stands out as a candidate source of VWM binding impairments because AD patients are known to have deficits of visual attention under certain conditions, and visual attention is involved in both encoding and maintenance stages. This proposal employs behavioral and electroencephalogram (EEG) methods to determine whether changes in visual attention, rather than perception and memory, underlie AD patients' diminished ability to bind features in VWM. The specific aims target the different factors that mediate VWM stages of encoding and maintenance. Aim 1 will test the hypothesis that AD-related impairments in VWM binding result from diminished visual attention during the encoding of information into VWM. One behavioral and one event-related potential (ERP) experiment under Aim 1 will use variations of the rapid serial visual presentation (RSVP) task to determine whether AD patients' binding errors result from perceptual deficits that lead to the loss of information or attentional deficits that lead to poor binding of information. Aim 2 will test the hypothesis that AD-related impairments in VWM binding result from diminished visual attention during the maintenance of information in VWM. One ERP experiment under Aim 2 will use a change detection task to determine whether AD patients' reduced VWM capacity for complex objects results from memory decay or impaired attentional binding, while one behavioral experiment will examine whether attention-based rehearsal will reduce VWM binding errors in AD patients and result in their improved VWM capacity for complex objects. The results of this research could potentially inform behavioral applications for accommodating the living environments for AD patients according to changes in their visual cognition. The results could also provide a potential target for pharmacological management. Such applications could help to ameliorate financial burdens on the family and the healthcare system in general by prolonging independent living and improving the quality of life of patients living with AD. PUBLIC HEALTH RELEVANCE: Alzheimer's disease patients suffer from impairments in visual working memory, a process that is important for basic visual abilities. The proposed research will determine the specific mechanism behind these patients' visual working memory deficits, targeting different stages of the process during which the deficit might occur. Understanding such changes to basic visual processing can be applied toward prolonging the functional abilities of those with Alzheimer's disease, potentially relieving a financial burden on the healthcare system and greatly informing caregivers of Alzheimer's disease patients.

描述（由申请人提供）：最近的研究表明，与健康的老年人相比，阿尔茨海默病（AD）患者对简单视觉特征的视觉工作记忆（VWM）能力正常。相比之下，AD患者对复杂物体的VWM能力下降，这是由于将复杂物体的视觉特征结合在一起的能力受损。了解这种结合损伤背后的认知和神经基础是至关重要的，因为VWM对于基本的视觉任务至关重要，例如导航新环境、注意景观变化、在混乱的空间中寻找物体和驾驶。几十年来的研究表明，VWM是一个复杂的过程，可以分为几个加工阶段。这包括编码的早期阶段，即对先前看到的信息进行心理表征，以及后期的维护阶段，即在不需要外部刺激的情况下存储表征。这些阶段有多种因素，包括知觉、注意力和记忆。重要的是，注意缺陷作为VWM结合障碍的候选来源，因为已知AD患者在某些条件下具有视觉注意缺陷，并且视觉注意涉及编码和维持阶段。本研究采用行为和脑电图（EEG）方法来确定AD患者对VWM特征结合能力下降的原因是否在于视觉注意力的变化，而不是感知和记忆的变化。具体目标针对介导VWM编码和维持阶段的不同因素。目的1将验证ad相关的VWM结合障碍是由于信息编码到VWM过程中视觉注意减少的假设。Aim 1下的一个行为和一个事件相关电位（ERP）实验将使用快速序列视觉呈现（RSVP）任务的变化来确定AD患者的结合错误是由导致信息丢失的知觉缺陷还是导致信息结合不良的注意缺陷引起的。目的2将验证ad相关的VWM结合障碍是由VWM信息维持过程中视觉注意减少引起的。Aim 2的ERP实验将使用变化检测任务来确定AD患者对复杂物体的VWM能力下降是由于记忆衰退还是注意绑定受损，而一个行为实验将研究基于注意的排练是否会减少AD患者的VWM绑定错误并导致他们对复杂物体的VWM能力提高。这项研究的结果可能会根据阿尔茨海默病患者的视觉认知变化，为适应他们的生活环境提供行为应用。结果也可以为药理学管理提供一个潜在的靶点。这种应用可以通过延长AD患者的独立生活和提高患者的生活质量来帮助减轻家庭和医疗保健系统的经济负担。