Díaz-Santos Mirella, Monge Zachary A, Salazar Robert D, Gilmore Grover C, Neargarder Sandy, Cronin-Golomb Alice
Department of Psychological and Brain Sciences Boston University Boston Massachusetts USA.
Jack, Joseph, and Morton Mandel School of Applied Social Sciences Case Western Reserve University Cleveland Ohio USA.
Mov Disord Clin Pract. 2020 Nov 17;8(1):51-59. doi: 10.1002/mdc3.13104. eCollection 2021 Jan.
Deficits in basic vision are associated with visual hallucinations in Parkinson's disease. Of particular interest is contrast sensitivity loss in this disorder and its effect on object identification.
Evaluate whether increased contrast improves object perception in persons with Parkinson's disease and visual hallucinations, without dementia.
We assessed 26 individuals with mild to moderate idiopathic Parkinson's disease, half of whom reported one or more episodes of hallucinations/unusual perceptual experiences in the past month, with a letter-identification task that determined the contrast level required to achieve 80% accuracy. Contrast sensitivity was further assessed with a chart that presented stimuli at multiple spatial frequencies. The groups were closely matched for demographic and clinical characteristics except for experience of hallucinations.
Relative to participants without visual hallucinations, those with hallucinations had poorer spatial frequency contrast sensitivity and required significantly greater contrast to correctly identify the letters on the identification task. Specifically, participants with hallucinations required a mean contrast of 52.8%, whereas participants without hallucinations required 35.0%. When given sufficient contrast, the groups with and without hallucinations were equally accurate in letter identification.
Compared to those without hallucinations, individuals with Parkinson's disease and hallucinations without dementia showed poorer contrast sensitivity. Once contrast was individually enhanced, the groups were equally accurate at object identification. These findings suggest the potential of visual perception tests to predict, and perception-based interventions to reduce, hallucinations in Parkinson's disease.
帕金森病患者的基本视觉缺陷与视幻觉有关。该疾病中的对比敏感度丧失及其对物体识别的影响尤其令人关注。
评估增加对比度是否能改善无痴呆的帕金森病伴视幻觉患者的物体感知能力。
我们评估了26例轻度至中度特发性帕金森病患者，其中一半在过去一个月内报告有一次或多次幻觉/异常感知经历，通过一项字母识别任务来确定达到80%准确率所需的对比度水平。使用一张在多个空间频率呈现刺激的图表进一步评估对比敏感度。除了幻觉经历外，两组在人口统计学和临床特征方面密切匹配。
与无视幻觉的参与者相比，有视幻觉的参与者空间频率对比敏感度较差，并且在识别任务中正确识别字母需要显著更高的对比度。具体而言，有视幻觉的参与者平均对比度需要52.8%，而无视幻觉参与者需要35.0%。当给予足够的对比度时，有和无视幻觉的两组在字母识别方面同样准确。
与无幻觉者相比，帕金森病伴无痴呆视幻觉患者的对比敏感度较差。一旦对比度得到个体化增强，两组在物体识别方面同样准确。这些发现表明视觉感知测试在预测帕金森病视幻觉以及基于感知的干预措施减少视幻觉方面具有潜力。
