Motor output oscillations with magnification of visual feedback in older adults
Motor output oscillations with magnification of visual feedback in older adults
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DOI：
10.1016/j.neulet.2017.03.011
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发表时间：
2017-04-24
影响因子：
2.5
通讯作者：
Christou, Evangelos A.
中科院分区：
文献类型：
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作者：
Park, Seoung Hoon;Kwon, MinHyuk;Christou, Evangelos A.
任务视觉反馈的放大增加了老年人的力量变异性。虽然在老年人中，随着视觉反馈放大而增加的力量变异性与低于0.5赫兹的力量振荡的放大有关，但与肌肉活动相关的频率调制仍然未知。因此，这项研究的目的是描述老年人肌肉活动的振荡，这种振荡有助于通过放大的视觉反馈放大力量的可变性。15名老年人(76.7+/-6.4岁，7名女性)在踝关节背屈、低增益(0.05度)或高增益视觉反馈(1.2度)的情况下，以最大自主收缩(MVC)的15%进行等长收缩。从低增益视觉反馈条件到高增益视觉反馈条件，力的标准差(SD)显著增加(55%)(P0.5)。力变异性的增加与0~0.5赫兹(R-2=0.37)的力振荡功率增加有关。在0.5~1.0赫兹(R-2=0.50)的范围内，肌电爆发振荡的功率越大，力振荡的强度越大。综上所述，这些发现表明，视觉反馈的放大改变了老年人运动神经元池的调制，并通过增加低于0.5赫兹的力振荡来加剧力的可变性。(C)2017爱思唯尔B.V.保留所有权利。
Magnification of task visual feedback increases force variability in older adults. Although the increased force variability with magnified visual feedback in older adults relates to the amplification of oscillations in force below 0.5 Hz, the related frequency modulation in muscle activity remains unknown. The purpose of this study, therefore, was to characterize the oscillations in muscle activity that contribute to the amplification of force variability with magnified visual feedback in older adults. Fifteen older adults (76.7 +/- 6.4 years, 7 females) performed isometric contractions at 15% of maximal voluntary contraction (MVC) with ankle dorsiflexion with low-gain (0.05 degrees) or high-gain visual feedback (1.2 degrees). The standard deviation (SD) of force increased significantly (55%) from low- to high-gain visual feedback condition (P0.5). The increase in force variability was related to greater power in force oscillations from 0 to 0.5 Hz (R-2=0.37). The increase in force oscillations was associated with greater power in EMG burst oscillations from 0.5 to 1.0 Hz (R-2=0.50). In conclusion, these findings suggest that magnification of visual feedback alters the modulation of the motor neuron pool in older adults and exacerbates force variability by increasing the oscillations in force below 0.5 Hz. (C) 2017 Elsevier B.V. All rights reserved.