Li Ke, Wei Na, Yue Shouwei, Thewlis Dominic, Fraysse Francois, Immink Maarten, Eston Roger
Laboratory of Motor Control and Rehabilitation, Institute of Biomedical Engineering, School of Control Science and Engineering, Shandong University, 17923 Jingshi Avenue, Jinan, 250061, Shandong, China,
Exp Brain Res. 2015 Jul;233(7):2053-60. doi: 10.1007/s00221-015-4276-y. Epub 2015 Apr 14.
This study examined the effects of handedness on the inter-digit coordination of force variability with and without concurrent visual feedback during sustained precision pinch. Twenty-four right-handed subjects were instructed to pinch an instrumented apparatus with their dominant and non-dominant hands, separately. During the pinch, the subjects were required to maintain a stable force output at 5 N for 1 min. Visual feedback was given for the first 30 s and removed for the second 30 s. Coefficient of variation and detrended fluctuation analysis were employed to examine the amount and structural variability of the thumb and index finger forces. Similarly, correlation coefficient and detrended cross-correlation analysis were applied to quantify the inter-digit correlation of force amount and structural variability. Results showed that, compared to the non-dominant hand, the dominant hand had higher inter-digit difference in the amount of digit force variability. Without visual feedback, the dominant hand exhibited lower digit force structural variability but higher inter-digit force structural correlation than the non-dominant hand. These results implied that the dominant hand would be more independent, less flexible and with lower dynamic degrees of freedom than the non-dominant hand in coordination of the thumb and index finger forces during sustained precision pinch. The effects of handedness on inter-digit force coordination were dependent on sensory condition, which shed light on higher-level sensorimotor mechanisms that may be responsible for the asymmetries in coordination of digit force variability.
本研究考察了利手在持续精确捏取过程中，有无同步视觉反馈时对指间力变异性协调的影响。24名右利手受试者被分别要求用优势手和非优势手捏一个装有传感器的仪器。在捏取过程中，受试者需要在5牛的力下保持稳定的力输出1分钟。前30秒提供视觉反馈，后30秒移除视觉反馈。采用变异系数和去趋势波动分析来考察拇指和食指力的大小和结构变异性。同样，应用相关系数和去趋势互相关分析来量化指间力大小和结构变异性的相关性。结果表明，与非优势手相比，优势手指间力变异性大小的差异更大。在没有视觉反馈的情况下，优势手的指力结构变异性较低，但指间力结构相关性高于非优势手。这些结果表明，在持续精确捏取过程中，在拇指和食指力的协调方面，优势手比非优势手更独立、灵活性更低且动态自由度更低。利手对指间力协调的影响取决于感觉条件，这为可能导致指力变异性协调不对称的高级感觉运动机制提供了线索。
