Enhanced stimulus strength improves visual cognition in aging and Alzheimer's disease
Enhanced stimulus strength improves visual cognition in aging and Alzheimer's disease
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DOI：
10.1016/s0010-9452(08)70693-2
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发表时间：
2007-10-01
期刊：
影响因子：
3.6
通讯作者：
Laudate, Thomas M.
中科院分区：
文献类型：
--
作者：
Cronin-Golomb, Alice;Gilmore, Grover C.;Laudate, Thomas M.
阿尔茨海默病（AD）的视觉认知缺陷源于皮层高阶关联区域的神经病理学变化和来自低水平视觉处理区域的有缺陷的输入。我们研究了增强的信号强度是否可能导致AD患者视觉认知的改善。我们测试了35个人与可能的AD，35个年龄匹配的老年对照（EC）和58个年轻的控制（YC）成人的字母识别，文字阅读，图片命名，不熟悉的面孔的歧视，和模式完成。使用AD和EC组的独立样本的对比敏感度阶差计算图像滤波器，从中我们产生低退化、中等正常和高增强的刺激强度条件。使用该过滤器，我们创建了中等强度AD和低强度EC之间以及高强度AD和中等强度EC之间的假设近端强度等效性。对于字母识别，字阅读，图片命名，和面对歧视，中等强度引起AD的准确性水平和反应时间，在低强度的EC相似。在图片命名，增加强度减少感知型错误EC和AD和随机错误AD。对于单词阅读，高强度引起AD的准确性水平和反应时间，相当于EC在中等强度。我们没有看到信号强度操纵对模式完成的影响，这可能是由于该任务的复杂认知要求或其图像的过滤器的不足。结果表明，AD-EC在认知方面的差异直接反映了各组之间的对比敏感度差异。刺激强度的增强可以改善基于视觉的缺陷，并导致认知表现的某些方面的改善。这些结果表明，新的非药物途径，以探索在试图改善认知老年人，特别是在个人与AD。
Deficits in visual cognition in Alzheimer's disease (AD) arise from neuropathological changes in higher-order association areas of the cortex and from defective input from lower-level visual processing areas. We investigated whether enhanced signal strength may lead to improvement of visual cognition in AD. We tested 35 individuals with probable AD, 35 age-matched elderly control (EC) and 58 young control (YC) adults on letter identification, word reading, picture naming, discrimination of unfamiliar faces, and pattern completion. The contrast sensitivity step-difference across an independent sample of AD and EC groups was used in calculating an image filter, from which we produced stimulus-strength conditions of low-degraded, medium-normal, and high-enhanced. Using this filter we created a hypothetical proximal-strength equivalence between AD at medium strength and EC at low strength, and between AD at high strength and EC at medium strength. For letter identification, word reading, picture naming, and face discrimination, medium strength elicited AD accuracy levels and reaction times that were similar to those of EC at low strength. On picture naming, increased strength reduced perceptual-type errors for EC and AD and random errors for AD. For word reading, high strength elicited AD accuracy levels and reaction times that were equivalent to those of EC at medium strength. We saw no effect of signal-strength manipulation on performance of pattern completion, possibly owing to the complex cognitive demands of that task or to the inadequacy of the filter for its images. The results indicate that putative AD-EC differences in cognition directly reflect contrast sensitivity differences between the groups. Enhancement of stimulus strength can ameliorate vision-based deficits and lead to improvement in some aspects of cognitive performance. These results suggest new non-pharmacological avenues to explore in the attempt to improve cognition in elderly adults and especially in individuals with AD.