高精度经颅直流电刺激对足部肌肉力量、踝关节运动觉及静态平衡的影响

Effects of High-definition Transcranial Direct Current Stimulation on Foot Muscle Strength,Ankle Kinesthesia,and Static Balance

目的:探究高精度经颅直流电刺激(HD-tDCS)对足部肌肉力量、踝关节运动觉及静态平衡的影响。方法:选取14名健康男性大学生,间隔1周对受试者进行单组随机双盲的HD-tDCS真刺激(持续20 min的2 mA电流强度的刺激)和假刺激(仅在开始时提供30 s的主动刺激)方案。采用重复测量双因素(刺激方案×刺激前后)方差分析上述自变量对受试者的足趾屈曲力量、跖趾关节屈肌力量、踝关节被动运动觉阈值及静态平衡各指标的影响。结果:HDtDCS干预后,受试者全部完成干预且无报道相关副作用和不良反应,推测刺激类型总体正确率为35.7%,致盲效果良好;真刺激后体重标准化后的第一足趾屈曲力量显著增加(P<0.05);真刺激后踝关节内翻运动觉阈值显著降低(P<0.05);真刺激后单足闭眼站立时重心前后、左右平均摆动速度显著降低(P<0.05)。结论:采用高精度经颅直流电刺激能够即刻提高足趾屈曲力量、降低踝关节内翻被动运动觉阈值,并改善单足闭眼站立平衡控制能力。提示,上述非侵入脑刺激技术是一种提升足部肌肉力量、足踝部感觉功能以及静态平衡能力的有效干预,可将其作为足部功能增强的手段。

To investigate the effects of a single-session high-definition transcranial direct current stimulation(HD-tDCS)on foot muscle strength,ankle kinesthesia,and static balance.In this double-blinded sham-controlled study,14 healthy young male college students completed two trials with a 20-minute session of tDCS targeting the sensorimotor cortex or a sham stimulation,respectively.Two-way ANOVA with repeated measures was used to analyze the effects of tDCS on the flexor strength of toes,the threshold of ankle passive kinesthesia,and static balance.All participants completed the experiments with no unexpected side effects or adverse events.The total correct rate of subjective guesses was 35.7%,which showed the blinding protocol was acceptable.Compared to pre-tDCS,a significant increase of the flexor strength of first toe(P<0.05),and decrease in the ankle varus passive kinesthesia(P<0.05)was observed after real tDCS,while no significant changes were observed after sham.Additionally,the anteroposterior and medio-lateral sway velocity of the center of gravity was significantly decreased in single-leg standing with closed eyes after real tDCS and sham(P<0.05).This study demonstrated that HD-tDCS can improve the flexor strength of the toes and reduce the ankle passive kinesthesia threshold immediately,and then improve the single-leg standing balance with closed eyes.It was suggested that the non-invasive brain stimulation technology may serve as a novel strategy to enhance foot muscle strength,foot perception function and static balance ability in daily training for foot core.