Visuomotor Correction is a Robust Contributor to Force Variability During Index Finger Abduction by Older Adults.
Visuomotor Correction is a Robust Contributor to Force Variability During Index Finger Abduction by Older Adults.
复制标题
DOI：
10.3389/fnagi.2015.00229
复制
发表时间：
2015
影响因子：
4.8
通讯作者：
Feldman-Kothe CE
中科院分区：
文献类型：
--
作者：
Tracy BL;Hitchcock LN;Welsh SJ;Paxton RJ;Feldman-Kothe CE
我们通过分析来自相似受试者的两个数据集，研究了视觉运动校正对食指外展期间力波动的贡献中与衰老相关的差异。研究 (1) 对年轻人 (N = 27, 23 ± 8 岁) 和老年人 (N = 14, 72 ± 9 岁) 进行最大随意收缩力 (MVC) 和恒力 (CF) 食指外展 (2.5, 30, 65% MVC) 过程中力量稳定性的评估。对于每次试验，提供力的视觉反馈 (VIS) 8-10 秒，并消除 8-10 秒 (NOVIS)。 2.5% MVC 时力反馈的视觉增益较高；比 30% 和 65% MVC 目标高 12 倍和 26 倍。针对去趋势（去除<0.5 Hz 漂移）的 VIS 和 NOVIS 数据段计算平均力、力的标准偏差 (SD) 和力的变异系数 (CV)。研究 (2) 由 14 名老年人组成的类似小组在低目标力 (1-3% MVC) 和高视觉增益下进行了离散、随机排序的 VIS 或 NOVIS 试验。研究 (1) 对于年轻人，VIS 和 NOVIS 之间的力 CV 相似，分别为 2.5%（4.8 vs. 4.3%）、30%（3.2 vs. 3.2%）和 65%（3.5 vs. 4.2%）目标力。相比之下，对于老年人来说，对于 2.5% MVC（6.6 vs. 4.2%，p < 0.001），VIS 的力 CV 大于 NOVIS，但对于 30%（2.4 vs. 2.4%）和 65%（3.1 vs. 3.3%）目标力则不然。在 2.5% MVC 时，与 NOVIS 相比，老年人 VIS 的力 CV 增加显着大于年轻人（年龄 × 视觉状况 p = 0.008）。研究 (2) 同样，对于进行离散、随机排序试验的老年人，VIS 的力 CV 大于 NOVIS（6.04 vs. 3.81%，p = 0.01）。当视觉力反馈是低力信息的主要来源时，老年人的归一化力变异性大约高出 58%，但年轻人仅高出 11%。视觉反馈对老年人的显着影响并不依赖于视觉条件的呈现顺序。结果表明，视觉运动信息处理受损是老年人在实验室手部肌肉等长收缩过程中观察到的更大运动变异性的基础。
We examined aging-related differences in the contribution of visuomotor correction to force fluctuations during index finger abduction via the analysis of two datasets from similar subjects. Study (1) Young (N = 27, 23 ± 8 years) and older adults (N = 14, 72 ± 9 years) underwent assessment of maximum voluntary contraction force (MVC) and force steadiness during constant-force (CF) index finger abduction (2.5, 30, 65% MVC). For each trial, visual feedback of the force (VIS) was provided for 8–10 s and removed for 8–10 s (NOVIS). Visual gain of the force feedback at 2.5% MVC was high; 12- and 26-fold greater than the 30 and 65% MVC targets. Mean force, standard deviation (SD) of force, and coefficient of variation (CV) of force was calculated for detrended (<0.5 Hz drift removed) VIS and NOVIS data segments. Study (2) A similar group of 14 older adults performed discrete, randomly-ordered VIS or NOVIS trials at low target forces (1–3% MVC) and high visual gain. Study (1) For young adults the CV of force was similar between VIS and NOVIS for the 2.5% (4.8 vs. 4.3%), 30% (3.2 vs. 3.2%) and 65% (3.5 vs. 4.2%) target forces. In contrast, for older adults the CV of force was greater for VIS than NOVIS for 2.5% MVC (6.6 vs. 4.2%, p < 0.001), but not for the 30% (2.4 vs. 2.4%) and 65% (3.1 vs. 3.3%) target forces. At 2.5% MVC, the increase in CV of force for VIS compared with NOVIS was significantly greater (age × visual condition p = 0.008) for older than young adults. Study (2) Similarly, for older adults performing discrete, randomly ordered trials the CV of force was greater for VIS than NOVIS (6.04 vs. 3.81%, p = 0.01). When visual force feedback was a dominant source of information at low forces, normalized force variability was ~58% greater for older adults, but only 11% greater for young adults. The significant effect of visual feedback for older adults was not dependent on the order of presentation of visual conditions. The results indicate that impaired processing of visuomotor information underlies the greater motor variability observed in older adults during lab-based isometric contractions of a hand muscle.