Hawkins Kara M, Sergio Lauren E
School of Kinesiology and Health Science, Centre for Vision Research, Neuroscience Graduate Diploma Program, York University, Toronto, ON, Canada.
J Alzheimers Dis. 2014;42(2):607-21. doi: 10.3233/JAD-140051.
Recent evidence suggests that visuomotor behaviors may be disrupted in the very early stages of Alzheimer's disease (AD). Here we propose that using kinematic measures under conditions that place demands on visual-spatial and cognitive-motor processing may provide an effective behavioral means to detect subtle changes associated with AD risk.
To this end, we have tested 22 young adults (mean age = 26.4 ± 4.1) and 22 older adults (mean age = 64.3 ± 10.1) at low AD, and 22 older adults (mean age = 67.7 ± 11.3) at high AD risk (i.e., strong family history or diagnosis of mild cognitive impairment). Kinematic measures were acquired on four visuomotor transformation tasks (standard, feedback reversal, plane dissociated, and plane dissociated + feedback reversal) using a dual-touchscreen tablet.
Comparing participants at increased AD risk with both young and old healthy control groups revealed significant performance disruptions in at-risk individuals as task demands increased. Furthermore, we were able to discriminate between individuals at high and low AD risk with a classification accuracy of 86.4% (sensitivity: 81.8%, specificity: 90.9%).
We suggest that the impairments observed in individuals at increased AD risk may reflect inherent brain alteration and/or early neuropathology disrupting the reciprocal communication between hippocampal, parietal, and frontal brain regions required to successfully prepare and update complex reaching movements. Such impairment has the potential to affect activities of daily living, and may serve as a sensitive measure of functional ability in at-risk adults.
近期证据表明，在阿尔茨海默病（AD）的极早期阶段，视运动行为可能会受到干扰。在此，我们提出，在对视觉空间和认知运动处理提出要求的条件下使用运动学测量方法，可能提供一种有效的行为手段，以检测与AD风险相关的细微变化。
为此，我们测试了22名低AD风险的年轻成年人（平均年龄 = 26.4 ± 4.1岁）、22名低AD风险的老年人（平均年龄 = 64.3 ± 10.1岁）以及22名高AD风险的老年人（平均年龄 = 67.7 ± 11.3岁，即有强烈家族病史或被诊断为轻度认知障碍）。使用双触摸屏平板电脑，在四项视运动转换任务（标准任务、反馈反转任务、平面分离任务以及平面分离 + 反馈反转任务）中获取运动学测量数据。
将高AD风险参与者与年轻和老年健康对照组进行比较发现，随着任务要求的增加，高风险个体的表现出现了显著干扰。此外，我们能够以86.4%的分类准确率（敏感性：81.8%，特异性：90.9%）区分高AD风险和低AD风险个体。
我们认为，在高AD风险个体中观察到的损伤可能反映了内在的大脑改变和/或早期神经病理学变化，这些变化破坏了海马体、顶叶和额叶脑区之间成功准备和更新复杂伸手动作所需的相互交流。这种损伤有可能影响日常生活活动，并可能作为高风险成年人功能能力的敏感指标。
