Bertone Armando, Bettinelli Line, Faubert Jocelyn
Visual Psychophysics and Perception Laboratory, Ecole d'Optométrie, Université de Montréal, Montréal, Canada.
J Clin Exp Neuropsychol. 2007 Jul;29(5):467-76. doi: 10.1080/13803390600770793.
The purpose of this study was to systematically assess the effect of blurred vision on several nonverbal neuropsychological measures commonly used as part of test batteries to assess the cognitive status of different patient populations. A total of 30 highly educated and healthy participants aged between 21 and 33 years were placed in one of three blurred vision groups, defined by their maximal visual acuity (20/20 or control group, 20/40, and 20/60). Blurred vision was simulated using positive diopters at a distance of 40 cm, the same distance as that at which tests were administered. Each participant was then assessed on a predetermined battery of nonverbal and verbal neuropsychological tests demanding different levels of acuity for optimal performance (i.e., tests whose items varied in terms of size and spatial frequency characteristics). In general, blurred vision significantly affected performance on nonverbal tests defined by small-sized/high-spatial-frequency items to a greater extent than on tests defined by larger sized/lower spatial-frequency items. As expected, blurred vision did not affect verbal test performance (Similarities, Information, and Arithmetic WAIS subtests). Our results are a clear indication of how even a "minimal" loss of visual acuity (20/40) can have a significant effect on the performance for certain nonverbal tests. In conclusion, such inferior performance is hypothetically interpretable as reflecting impaired cognitive functioning (i.e., attentional) targeted by a specific task (i.e., visual search) and suggests that the precision of the cognitive assessment and subsequent diagnosis are significantly biased when visuo-sensory abilities are not optimal, particularly for older patient populations where blurred vision resulting from correctable visual impairment is quite common.
本研究的目的是系统评估视力模糊对几种常用的非语言神经心理学测量方法的影响，这些方法常用于评估不同患者群体认知状态的测试组合中。共有30名年龄在21至33岁之间、受过高等教育的健康参与者被分为三个视力模糊组之一，根据他们的最大视力进行定义（20/20或对照组、20/40和20/60）。在40厘米的距离使用正屈光度模拟视力模糊，这与进行测试的距离相同。然后，对每位参与者进行一组预先确定的非语言和语言神经心理学测试，这些测试需要不同程度的视力清晰度以达到最佳表现（即测试项目在大小和空间频率特征方面有所不同）。一般来说，视力模糊对由小尺寸/高空间频率项目定义的非语言测试的表现影响显著，程度大于对由大尺寸/低空间频率项目定义的测试的影响。正如预期的那样，视力模糊不影响语言测试表现（韦氏成人智力量表的相似性、信息和算术子测试）。我们的结果清楚地表明，即使是“最小程度”的视力丧失（20/40）也会对某些非语言测试的表现产生显著影响。总之，这种较差的表现假设可解释为反映了特定任务（即视觉搜索）所针对的认知功能（即注意力）受损，并表明当视觉感觉能力不理想时，认知评估和后续诊断的准确性会受到显著偏差，特别是对于老年患者群体，其中由可矫正视力损害导致的视力模糊相当常见。
