Bahadorani Nastaran, Khanmohammadi Roya
Physical Therapy Department, Rehabilitation Faculty, Tehran University of Medical Sciences, Tehran, Iran.
Sci Rep. 2025 Apr 8;15(1):11966. doi: 10.1038/s41598-025-92617-1.
Several cortical regions, such as the cerebellum, posterior parietal cortex (PPC), anterior cingulate cortex (ACC), and primary motor cortex (M1), play critical roles in postural adaptation. However, studies examining the effects of transcranial direct current stimulation (tDCS) on postural adaptation in healthy individuals are limited and often yield inconsistent findings, making it challenging to draw definitive conclusions. Most research has focused on individual brain regions, leaving a gap in understanding how the cerebellum, PPC, ACC, and M1 differentially contribute to postural adaptation. Identifying the most effective brain regions for postural adaptation could optimize rehabilitation strategies for individuals with postural control impairments. Thus, this study compared the effects of tDCS over these specific brain regions on postural adaptation. This parallel, randomized, double-blinded, controlled trial involved 75 participants, divided into five groups: anodal stimulation of the PPC, cerebellum, M1, ACC, or a sham group. Each group received 20 min of direct current stimulation in a single session. Center of pressure (COP) displacement, path length, velocity, and standard deviation (SD) were measured across three trials in the anteroposterior (AP) direction during standing disturbed using vibrators attached to bilateral Achilles tendons. A repeated measure ANOVA was used to assess within-group effects, while one-way ANOVA compared between-group differences. Between-group analysis did not reveal statistically significant differences during both the vibration and post-vibration phases. Nonetheless, the within-group analysis revealed significant enhancements in postural adaptation for the PPC and cerebellum groups during the vibration phase. Specifically, the PPC group demonstrated significant reductions in COP displacement (P = 0.005), path length (P = 0.018), and SD of COP displacement (P = 0.045) across trials. Similarly, in the cerebellar group, significant improvements were noted in COP displacement (P = 0.044), velocity (P = 0.006), and phase plane (P = 0.016) across trials. In contrast, no significant changes were found in the M1, ACC, or sham groups during either the vibration or post-vibration phases. In conclusion, while intergroup comparisons were not significant, intra-group analysis revealed that PPC and cerebellar stimulation significantly enhanced postural adaptation. Incorporating tDCS over the PPC or cerebellum in postural training programs could improve postural control, potentially reducing fall risk in clinical populations such as older adults or individuals with neurological dysfunction.RCT registration: On the Iranian Registry of Clinical Trials (IRCT20220819055745N1). Registration date: 15/11/2022.
几个皮质区域，如小脑、顶叶后皮质（PPC）、前扣带回皮质（ACC）和初级运动皮质（M1），在姿势适应中发挥着关键作用。然而，研究经颅直流电刺激（tDCS）对健康个体姿势适应影响的研究有限，且结果往往不一致，难以得出明确结论。大多数研究集中在单个脑区，在理解小脑、PPC、ACC和M1如何不同地促进姿势适应方面存在空白。确定对姿势适应最有效的脑区可以优化针对姿势控制受损个体的康复策略。因此，本研究比较了tDCS作用于这些特定脑区对姿势适应的影响。这项平行、随机、双盲、对照试验纳入了75名参与者，分为五组：PPC、小脑、M1、ACC阳极刺激组或假刺激组。每组在单次治疗中接受20分钟的直流电刺激。在使用附着于双侧跟腱的振动器干扰站立期间，在前后（AP）方向的三次试验中测量压力中心（COP）位移、路径长度、速度和标准差（SD）。采用重复测量方差分析评估组内效应，单向方差分析比较组间差异。组间分析在振动期和振动后期均未发现统计学上的显著差异。尽管如此，组内分析显示，在振动期，PPC组和小脑组的姿势适应有显著增强。具体而言，PPC组在各试验中COP位移（P = 0.005）、路径长度（P = 0.018）和COP位移标准差（P = 0.045）均显著降低。同样，在小脑组中，各试验中COP位移（P = 0.044）、速度（P = 0.006）和相平面（P = 0.016）均有显著改善。相比之下，M1组、ACC组或假刺激组在振动期或振动后期均未发现显著变化。总之，虽然组间比较无显著差异，但组内分析显示，PPC和小脑刺激显著增强了姿势适应。在姿势训练计划中加入PPC或小脑的tDCS可以改善姿势控制，可能降低老年或神经功能障碍等临床人群的跌倒风险。RCT注册：在伊朗临床试验注册中心（IRCT20220819055745N1）。注册日期：2022年11月15日。
