老年人反复短暂向前平移时动态姿势控制和条件负变的适应性变化。
Adaptation changes in dynamic postural control and contingent negative variation during repeated transient forward translation in the elderly.
机构信息
Department of Human Movement and Health, Graduate School of Medical Science, Kanazawa University, 13-1 Takara-machi, Kanazawa 920-8640, Japan.
出版信息
J Physiol Anthropol. 2013 Dec 19;32(1):24. doi: 10.1186/1880-6805-32-24.
BACKGROUND
Adaptation changes in postural control and contingent negative variation (CNV) for the elderly were investigated during repeated forward floor translation.
METHODS
Fifteen healthy elderly persons, living in the suburban area of Kanazawa City, Japan, underwent backward postural disturbance by a forward-floor translation (S2) 2 s after an auditory warning signal (S1). A set with 20 trials was repeated until a negative peak of late CNV was recognized in the 600-ms period before S2, and the last set was defined as the final set. Electroencephalograms, center of foot pressure in the anteroposterior direction (CoPap), and electromyograms of postural muscles were analyzed.
RESULTS
CoPap displacement generated by the floor translation was significantly decreased until the twelfth trial in the first set, and mean CoPap displacement was smaller in the second and final sets than in the first set. The mean displacement was significantly smaller in the final set than the previous set. A late CNV with a negative peak was not recognized in the first and second sets. However, most subjects (13/15) showed a negative peak by the fourth set, when the late CNV started to increase negatively from about 1,000 ms after S1 and peaked at about 300 ms before S2. At about 160 ms before the CNV peak, the CoPap forward shift started. The increase in timing of the gastrocnemius activity related to the CoPap shift was significantly correlated with the CNV peak timing (r = 0.64). After S2, peak amplitudes of the anterior postural muscles were significantly decreased in the final set compared to the first set.
CONCLUSIONS
It was demonstrated that even for the elderly, with so many repetitions of postural disturbance, a late CNV with a negative peak was recognized, leading to accurate postural preparation. This suggests the improvement of frontal lobe function (e.g., anticipatory attention and motor preparation) in the elderly.
背景
本研究旨在探讨老年人在反复进行向前地板平移时，姿势控制和条件负变（CNV）的适应性变化。
方法
15 名居住在日本金泽市郊区的健康老年人在听觉警告信号（S1）后 2 秒接受向前地板平移（S2）的向后姿势干扰。在 S2 前 600ms 期间，直到识别出晚期 CNV 的负峰，重复一组 20 次试验，最后一组被定义为最终组。分析了脑电图、前后方向的足底压力中心（CoPap）和姿势肌肉的肌电图。
结果
在第一组的前 12 次试验中，地板平移产生的 CoPap 位移明显减小，并且第二组和最终组的平均 CoPap 位移小于第一组。最终组的平均位移明显小于前一组。第一组和第二组没有识别出具有负峰的晚期 CNV。然而，大多数受试者（13/15）在第四组时显示出负峰，此时晚期 CNV 开始从 S1 后约 1000ms 开始负向增加，并在 S2 前约 300ms 达到峰值。在 CNV 峰值前约 160ms，CoPap 向前移位开始。与 CoPap 移位相关的腓肠肌活动的定时增加与 CNV 峰值定时显著相关（r=0.64）。在 S2 之后，最终组中前向姿势肌肉的峰值幅度与第一组相比显著降低。
结论
即使对于老年人，在进行如此多的姿势干扰重复后，也可以识别出具有负峰的晚期 CNV，从而进行准确的姿势准备。这表明老年人额叶功能（例如，预期注意和运动准备）得到了改善。
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