Increased Force Variability in Chronic Stroke: Contributions of Force Modulation below 1 Hz
Increased Force Variability in Chronic Stroke: Contributions of Force Modulation below 1 Hz
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DOI：
10.1371/journal.pone.0083468
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发表时间：
2013-12-26
期刊：
影响因子：
3.7
通讯作者：
Cauraugh, James H.
中科院分区：
文献类型：
--
作者：
Lodha, Neha;Misra, Gaurav;Cauraugh, James H.
力量变异性增加是中风后手臂残疾的一个标志。在健康的年轻人和老年人中，力的可变性与低于1赫兹的力的调节有关。然而，卒中后观察到的力量变异性增加是否与低于1赫兹的力量调制有关仍不清楚。因此，这项研究的目的是比较慢性中风和年龄匹配的健康个体中低于1赫兹的力量调制。中风患者和对照组(N=26)都完成了低于最大力量水平的等长握力任务。变异系数量化了力的可变性，力的功率谱密度以高分辨率(0.07赫兹)量化了低于1赫兹的力调制。分析表明，与健康对照组相比，中风组的力量变异性更大，而与非瘫痪手相比，偏瘫手的力变异性更大。在1赫兹以下的力量调制区分中风患者和健康对照，以及偏瘫和非偏瘫的手。具体地说，与健康对照组(非优势手)相比，中风患者(偏瘫手)表现出与0.2赫兹(0.07-0.35赫兹)相似的较大功率和较小的0.6赫兹(0.49-0.77赫兹)功率。类似地，瘫痪的手比非瘫痪的手表现出更大的功率，0.2赫兹，而更小的功率，类似于0.6赫兹。此外，根据低于1赫兹的特定频率的调制，力的可变性被强烈地预测(R2=0.80)。总之，这些发现表明，低于1赫兹的力量调制提供了对中风后运动控制变化的显著洞察。
Increased force variability constitutes a hallmark of arm disabilities following stroke. Force variability is related to the modulation of force below 1 Hz in healthy young and older adults. However, whether the increased force variability observed post stroke is related to the modulation of force below 1 Hz remains unknown. Thus, the purpose of this study was to compare force modulation below 1 Hz in chronic stroke and age-matched healthy individuals. Both stroke and control individuals (N = 26) performed an isometric grip task to submaximal force levels. Coefficient of variation quantified force variability, and power spectrum density of force quantified force modulation below 1 Hz with a high resolution (0.07 Hz). Analyses indicated that force variability was greater for the stroke group compared with to healthy controls and for the paretic hand compared with the non-paretic hand. Force modulation below 1 Hz differentiated the stroke individuals and healthy controls, as well as the paretic and non-paretic hands. Specifically, stroke individuals (paretic hand) exhibited greater power similar to 0.2 Hz (0.07-0.35 Hz) and lesser power,0.6 Hz (0.49-0.77 Hz) compared to healthy controls (non-dominant hand). Similarly, the paretic hand exhibited greater power,0.2 Hz, and lesser power similar to 0.6 Hz than the non-paretic hand. Moreover, variability of force was strongly predicted from the modulation of specific frequencies below 1 Hz (R-2 = 0.80). Together, these findings indicate that the modulation of force below 1 Hz provides significant insight into changes in motor control after stroke.