Optic Flow and Spatial Navigation in Parkinson's Disease

描述(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，其视觉空间认知功能的多个方面受到损害，包括空间导航。空间导航功能障碍源于大脑高阶关联区的病理改变，但也源于低级视觉处理区域的输入缺陷，包括那些调节光流的区域。视流是指表明一个人的自我运动方向并保持步态和姿势完整性的放射状视觉模式。视流知觉在帕金森病中的状态尚不清楚，它与空间导航中的帕金森病的关系也是未知的，如行走时无法保持笔直的路径。我们建议研究帕金森病患者的视流知觉及其与空间导航的关系。一个关键的焦点是起病侧的运动障碍，对侧的大脑半球有主要的基底节功能障碍。帕金森病通常为单侧发病，许多视空间异常是由右脑功能障碍引起的。我们的初步研究表明，伴有左侧运动发作的帕金森病患者左侧视觉半侧视野受到空间压缩，这影响了他们理解空间关系和利用空间信息进行导航的能力。我们预测，视流感知的缺陷是这种感知到的空间压缩的基础。具体地说，光流速度的半场差异会导致患者错误地认为一条直线路径是朝着空间的压缩侧弯曲的，他们通过走曲线路径来“纠正”他们的轨迹。我们建议对18例左侧帕金森病患者、18例右侧帕金森病患者、18例健康老年人和18名健康年轻成年人的视流和空间导航进行研究。我们的具体目标是：(1)操纵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，这与自我运动的感知方向有关。(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，并记录参与者在真实空间行走时的方向和空间位置。(3)通过问卷调查，将视流和空间导航与日常功能联系起来。我们的项目在概念上是创新的，提出了光流缺陷作为PD空间导航问题的一个原因，并将在这一潜在重要领域产生试点数据。我们在视觉心理物理学、行为神经科学、生物医学工程和物理治疗方面的专家之间建立了新的合作关系，以实现该项目的目标。

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.