Sensory Information Processing with Low Vision

描述（申请人提供）：过马路是一项复杂、高风险的日常生活活动。行人在决定何时过马路是安全的时候，必须判断车辆之间是否有足够的间隔，使他们能够到达街道的另一边或分隔岛。行人通过处理从环境中获得的复杂感官信息来识别可穿越的间隙。毫无疑问，视觉感官信息在检测交叉间隙的准确性和效率方面起着不可或缺的作用。然而，当视觉信息减少时，其他感官信息来源的相对重要性却鲜为人知。在视觉信息退化的情况下，听觉感知信息可能在过马路过程中发挥重要作用，因为盲人可以安全独立地过马路。为了确定视障行人过马路时听觉感知信息是否增强了视觉感知信息，首先必须建立一种可靠的经验评估方法。本研究的目的是验证使用受试者工作特征（ROC）曲线来评估低视力人群过马路时的视觉和听觉信息处理。使用5分评定量表，对正常视力、视障和失明受试者的不同持续时间的可穿越间隔进行安全评定。对于正常视力和视障受试者，将在3种感官测试条件下收集安全评级：(i)视觉和听觉信息；（ii）只提供视觉资料；（三）仅听信息。盲人受试者的安全评级将仅来自听觉信息。在正态偏差（z-score）坐标上构建ROC曲线将检验本研究中应用的ROC曲线是否为评估低视力人群过马路感觉信息处理的有效指标。比较测试条件和受试者组之间不同间隙持续时间的可判别性（d'），将确定度量标准可以测量听觉效果以及视觉感官通道性能变化的范围。鉴于行人安全已被认为是一个主要的公共健康问题，拟议的研究将提供数据，形成一个客观的基础，以制定培训计划，移动设备和环境变化，旨在帮助视障行人过马路。

DESCRIPTION (provided by applicant): Crossing a street is a complicated, high-risk activity of daily living. In making an appropriate decision of when it is safe to cross, pedestrians must judge gaps in vehicular traffic that is of sufficient duration to allow them to reach the other side of the street or a splitter island. Pedestrians identify crossable gaps by processing complex sensory information acquired from the environment. Undoubtedly, visual sensory information plays an integral role in the accuracy and efficiency of detecting crossable gaps. Little is known however, about the relative importance of other sources of sensory information when visual information is reduced. Auditory sensory information may play an important role in street crossing when visual information is degraded since blind people can successfully cross a street safely and independently. To determine if auditory sensory information augments visual sensory information in street crossing for visually impaired pedestrians, a reliable, empirical method of assessment must first be established. The proposed research has the goal of validating the use of receiver operating characteristic (ROC) curves to assess visual and auditory information processing for street crossing in people with low vision. Using a 5 point rating scale, safety ratings for crossable gaps of different durations will be measured in normally sighted, visually impaired and blind subjects. For the normally sighted and visually impaired subjects, safety ratings will be collected under 3 sensory test conditions: (i) visual and auditory information; (ii) visual information only; and (iii) auditory information only. The safety ratings of blind subjects will be from auditory information only. Constructing ROC curves on normal-deviate (z-score) coordinates will test whether or not ROC curves as applied in the proposed study is a valid metric for assessing sensory information processing for street crossing in low vision. Comparing the discriminability (d') of different gap durations between test conditions and subject groups will establish the range over which the metric can measure an auditory effect as well as changes in performance in the visual sensory channel. Given that pedestrian safety has been recognized as a major public health concern, the proposed research will provide data to form an objective base for the development of training programs, mobility devices and environmental changes designed to assist visually impaired pedestrians cross a street.