Universidad de Valladolid, Valladolid, Spain.
Instituto Universitario de Oftalmobiología Aplicada (IOBA), Eye Institute, Universidad de Valladolid, Valladolid, Spain.
J Neuroeng Rehabil. 2020 Jan 31;17(1):12. doi: 10.1186/s12984-020-0650-5.
There is a clinical need to identify diagnostic parameters that objectively quantify and monitor the effective visual ability of patients with homonymous visual field defects (HVFDs). Visual processing speed (VPS) is an objective measure of visual ability. It is the reaction time (RT) needed to correctly search and/or reach for a visual stimulus. VPS depends on six main brain processing systems: auditory-cognitive, attentional, working memory, visuocognitive, visuomotor, and executive. We designed a new assessment methodology capable of activating these six systems and measuring RTs to determine the VPS of patients with HVFDs.
New software was designed for assessing subject visual stimulus search and reach times (S-RT and R-RT respectively), measured in seconds. Thirty-two different everyday visual stimuli were divided in four complexity groups that were presented along 8 radial visual field positions at three different eccentricities (10, 20, and 30). Thus, for each HVFD and control subject, 96 S- and R-RT measures related to VPS were registered. Three additional variables were measured to gather objective data on the validity of the test: eye-hand coordination mistakes (ehcM), eye-hand coordination accuracy (ehcA), and degrees of head movement (dHM, measured by a head-tracker system). HVFD patients and healthy controls (30 each) matched by age and gender were included. Each subject was assessed in a single visit. VPS measurements for HFVD patients and control subjects were compared for the complete test, for each stimulus complexity group, and for each eccentricity.
VPS was significantly slower (p < 0.0001) in the HVFD group for the complete test, each stimulus complexity group, and each eccentricity. For the complete test, the VPS of the HVFD patients was 73.0% slower than controls. They also had 335.6% more ehcMs, 41.3% worse ehcA, and 189.0% more dHMs than the controls.
Measurement of VPS by this new assessment methodology could be an effective tool for objectively quantifying the visual ability of HVFD patients. Future research should evaluate the effectiveness of this novel method for measuring the impact that any specific neurovisual rehabilitation program has for these patients.
需要找到客观的诊断参数来定量和监测同侧偏盲患者的有效视觉能力。视觉处理速度（VPS）是视觉能力的客观衡量标准。它是指正确搜索和/或触及视觉刺激所需的反应时间（RT）。VPS 取决于六个主要的大脑处理系统：听觉认知、注意力、工作记忆、视认知、视运动和执行。我们设计了一种新的评估方法，能够激活这六个系统并测量 RT，以确定同侧偏盲患者的 VPS。
为评估患者视觉刺激搜索和到达时间（分别为 S-RT 和 R-RT），我们设计了新的软件，以秒为单位进行测量。将 32 种不同的日常视觉刺激分为四个复杂度组，分别呈现在 8 个不同的放射状视野位置和三个不同的偏心度（10、20 和 30）上。因此，对于每个同侧偏盲患者和对照者，共记录了 96 个与 VPS 相关的 S-RT 和 R-RT 测量值。为了收集测试有效性的客观数据，还测量了三个附加变量：手眼协调错误（ehcM）、手眼协调准确性（ehcA）和头部运动程度（dHM，通过头部跟踪系统测量）。纳入了年龄和性别匹配的 30 名同侧偏盲患者和 30 名健康对照者。每位受试者在单次就诊时进行评估。比较了同侧偏盲患者和健康对照者的完整测试、每个刺激复杂度组和每个偏心度的 VPS 测量值。
同侧偏盲患者的 VPS 在完整测试、每个刺激复杂度组和每个偏心度下均显著较慢（p<0.0001）。对于完整测试，同侧偏盲患者的 VPS 比对照组慢 73.0%。他们的 ehcM 多 335.6%，ehcA 差 41.3%，dHM 多 189.0%。
通过这种新的评估方法测量 VPS 可能是客观量化同侧偏盲患者视觉能力的有效工具。未来的研究应该评估这种新方法测量任何特定神经视觉康复计划对这些患者的影响的有效性。
