Department of Bioengineering, George Mason University, Fairfax, VA, USA.
Department of Mechanical Engineering, George Mason University, Fairfax, VA, USA.
Exp Brain Res. 2022 Sep;240(9):2513-2521. doi: 10.1007/s00221-022-06432-5. Epub 2022 Aug 19.
Despite numerous studies that show force regulation is impaired after stroke, two recent studies suggest that the ability to regulate submaximal, isometric grip forces may remain substantially intact. Here we asked how this aspect of hand motor control, measured for both a power grip and pinch grip, compares to two other key aspects of hand function-grip strength and dexterity. For 20 individuals with a range of hand impairment levels in the chronic phase of stroke (Age: 62 ± 16.0 years, Time post stroke: 958.3 ± 966.5 days, Sex: 19 M 1F) we quantified the average rate of target acquisition for force targets in the range of 3 to 30% maximum voluntary contraction as participants used the two different grips to squeeze a force sensor to control a cursor on a screen. The same force sensor was used to assess subject grip strength for the two grips, while dexterity was assessed using the Box and Blocks Test (BBT), and the Nine Hole Peg Test (NHPT) for both the paretic and non-paretic hand. On average, the relative rate of force acquisition of the paretic hand using a power grip was 74.0 ± 18.6 SD % of the non-paretic hand, a value significantly higher than the 48.6 ± 25.6 SD% for grip strength (paired t test, p < .005) or the 41.4 ± 29.1 SD % (p < .005) and 23.3 ± 30.1 SD % (p < .005) for the BBT and NHPT, respectively. Results were similar for the lateral pinch grip, suggesting similar thumb force tracking performance. Grip force tracking, measured as rate of force acquisition, is less impaired after stroke than hand strength or dexterity, a finding with implications for the neural mechanisms of stroke and the design of assistive technologies.
尽管有大量研究表明中风后力量调节受损，但最近两项研究表明，调节亚最大等长握力的能力可能基本完好。在这里，我们想知道这种手运动控制的方面，既针对力量握力又针对捏力进行测量，与手功能的另外两个关键方面——握力和灵活性相比如何。对于 20 名处于中风慢性期的个体（年龄：62±16.0 岁，中风后时间：958.3±966.5 天，性别：19 男 1 女），我们量化了参与者使用两种不同握法挤压力传感器以控制屏幕上光标时，力目标在 3%至 30%最大自主收缩范围内的目标获取的平均速率。同一力传感器用于评估两种握法的个体握力，而使用 Box and Blocks Test（BBT）和 Nine Hole Peg Test（NHPT）评估灵活性，分别用于患侧手和非患侧手。平均而言，使用力量握法的患侧手的力量获取相对速率为非患侧手的 74.0±18.6 SD%，这一值显著高于握力的 48.6±25.6 SD%（配对 t 检验，p<.005）或 BBT 和 NHPT 的 41.4±29.1 SD%（p<.005）和 23.3±30.1 SD%（p<.005）。侧向捏力的结果相似，表明拇指力量跟踪性能相似。与手强度或灵活性相比，力量跟踪，以力量获取速率来衡量，中风后受损程度较小，这一发现对中风的神经机制和辅助技术的设计具有影响。
