Optic Flow and Spatial Navigation in Parkinson's Disease

描述（由申请人提供）：帕金森病（PD）是一种常见的与年龄相关的神经退行性疾病，其中视觉空间认知功能的多个方面受损，包括空间导航。空间导航的缺陷是由大脑高阶关联区域的病理改变引起的，但也由来自较低水平视觉处理区域的输入缺陷引起，包括那些介导光流的区域。光流是指指示一个人自我运动方向并保持步态和姿势完整性的径向视觉模式。光流感知在帕金森病中的地位尚不清楚，它与帕金森病空间导航缺陷的关系也不清楚，比如行走时无法保持直线路径。我们建议研究PD中的光流感知及其与空间导航的关系。一个关键的焦点是运动障碍的发病侧，对侧的半球与主要的基底节区功能障碍。PD通常单侧发病，许多视觉空间异常由右半球功能障碍引起。我们的初步研究表明，左运动起病的PD患者会经历左视半球的空间压缩，这影响了他们理解空间关系和使用空间信息进行导航的能力。我们预测光流感知的缺陷是这种感知空间压缩的基础。具体来说，光流速度的半场差异导致患者将直线路径误认为是弯曲的，而他们通过走弯曲的路径来“纠正”自己的轨迹。我们拟研究18例左发病PD患者、18例右发病PD患者、18例健康老年人和18例健康青壮年的光流和空间导航功能。我们的具体目标是：(1)控制两个视觉半球的光流速度，并测量每个参与者对相对速度的感知，这与感知到的自我运动方向有关。(2)将光流与空间导航联系起来。我们将使用一个头戴式系统，提供虚拟视觉输入，并记录参与者在穿越真实空间时的方向和空间位置。(3)将光流和空间导航与日常功能联系起来，通过问卷调查进行评估。我们的项目在概念上是创新的，提出光流缺陷是PD空间导航问题的原因，并将在这个潜在的重要领域产生试点数据。我们已经与视觉心理物理学、行为神经科学、生物医学工程和物理治疗方面的专家建立了新的合作关系，以实现这个项目的目标。

DESCRIPTION (provided by applicant): Parkinson's disease (PD) is a common age-related neurodegenerative disorder in which multiple aspects of visuospatial cognitive function are impaired, including spatial navigation. Deficits in spatial navigation arise from pathological changes in high-order association areas of the brain but also from defective input from lower-level visual processing areas, including those that mediate optic flow. Optic flow refers to the radial visual patterns that indicate a person's direction of self-movement and maintain gait and postural integrity. The status of optic flow perception in PD is unknown, as is its relation to PD deficits in spatial navigation, such as the inability to maintain a straight path while walking. We propose to examine optic flow perception in PD and its relation to spatial navigation. A critical focus is on the side of onset of motor impairment, contralateral to the hemisphere with predominant basal ganglia dysfunction. PD usually has unilateral onset, and many visuospatial abnormalities arise from right-hemisphere dysfunction. Our preliminary studies suggest that PD patients with left motor onset experience spatial compression of the left visual hemifield, which affects their ability to understand spatial relations and to use spatial information for navigation. We predict that deficits in optic flow perception underlie this perceived spatial compression. Specifically, hemifield differences in optic flow velocities lead patients to misperceive a straight path as curved toward the compressed side of space, and they "correct" their trajectory by walking a curved path. We propose to investigate optic flow and spatial navigation in 18 patients with left-onset PD, 18 with right-onset PD, 18 healthy elderly adults, and 18 healthy young adult adults. Our specific aims are: (1) To manipulate the speed of optic flow in the two visual hemifields and measure each participant's perception of relative speed, which is associated with perceived direction of self-motion. (2) To relate optic flow to spatial navigation. We will use a head-mounted system that provides virtual visual input and records the orientation and spatial position of the participant while walking through veridical space. (3) To relate optic flow and spatial navigation to daily function, as assessed with questionnaires. Our project is conceptually innovative in proposing optic flow deficiencies as a cause of problems of spatial navigation in PD and will generate pilot data in this potentially important area. We have forged novel collaborations between experts in visual psychophysics, behavioral neuroscience, biomedical engineering, and physical therapy to accomplish the goals of this project.