da Silva Fabiana Tenório Gomes, Browne Rodrigo Alberto Vieira, Pinto Camila Bonin, Saleh Velez Faddi Ghassan, do Egito Eryvaldo Sócrates Tabosa, do Rêgo Jeferson Tafarel Pereira, da Silva Marília Rodrigues, Dantas Paulo Moreira Silva, Fregni Felipe
Laboratory of Neuromodulation, Center of Clinical Research Learning, Spaulding Rehabilitation Hospital, Harvard Medical School, Boston, MA, USA.
Psychology institute, Department of Neurosciences and behavior, University of São Paulo (USP), São Paulo, Brazil.
Restor Neurol Neurosci. 2017;35(2):159-169. doi: 10.3233/RNN-160685.
We hypothesized in this study that transcranial direct current stimulation (tDCS) of primary motor cortex could exert top-down modulation over subcortical systems associated with autonomic control and thus be useful to revert some of the dysfunctional changes found in the autonomic nervous system (ANS) of subjects with spinal cord injuries (SCI).
To explore the acute effect of tDCS on ANS indexed by Heart Rate Variability (HRV) in individuals with SCI and analyze whether this effect depends on the gender, degree, level and time of injury.
In this randomized, placebo-controlled, crossover, double-blinded study, 18 adults with SCI (32.9±7.9 years old) were included; the intervention consisted of a single 12-minute session of active tDCS (anodal, 2 mA) and a control session of sham tDCS applied over Cz (bihemispheric motor cortex). HRV was calculated using spectral analysis. Low-frequency (LF), high-frequency (HF), and LF/HF ratio variables were evaluated before, during, and post tDCS.
A two-way repeated measures ANOVA showed that after active (anodal) stimulation, LF/HF ratio was significantly increased (P = 0.013). There was a trend for an interaction between time and stimulation for both LF and HF (P = 0.052). Paired exploratory t-tests reported effects on the difference of time [post-pre] between stimulation conditions for LF (P = 0.052), HF (P = 0.052) and LF/HF (P = 0.003).
Anodal tDCS of the motor cortex modulated ANS activity in individuals with SCI independent of gender, type and time of lesion. These changes were in the direction of normalization of ANS parameters, thus confirming our initial hypothesis that an enhancement of cortical excitability by tDCS could at least partially restore some of the dysfunctional activity in the ANS system of subjects with SCI.
在本研究中，我们假设对初级运动皮层进行经颅直流电刺激（tDCS）可对与自主控制相关的皮层下系统发挥自上而下的调节作用，因此有助于恢复脊髓损伤（SCI）患者自主神经系统（ANS）中发现的一些功能失调变化。
探讨tDCS对SCI患者心率变异性（HRV）所索引的ANS的急性影响，并分析这种影响是否取决于性别、损伤程度、损伤平面和损伤时间。
在这项随机、安慰剂对照、交叉、双盲研究中，纳入了18名成年SCI患者（32.9±7.9岁）；干预包括一次12分钟的阳极tDCS（2毫安）有效刺激和一次在Cz（双侧运动皮层）应用的假tDCS对照刺激。使用频谱分析计算HRV。在tDCS前、期间和之后评估低频（LF）、高频（HF）和LF/HF比值变量。
双向重复测量方差分析表明，在有效（阳极）刺激后，LF/HF比值显著增加（P = 0.013）。LF和HF的时间与刺激之间存在交互作用趋势（P = 0.052）。配对探索性t检验报告了刺激条件之间LF（P = 0.052）、HF（P = 0.052）和LF/HF（P = 0.003）的时间[后 - 前]差异效应。
运动皮层的阳极tDCS可调节SCI患者的ANS活动，且与性别、损伤类型和时间无关。这些变化朝着ANS参数正常化的方向发展，从而证实了我们最初的假设，即tDCS增强皮层兴奋性可至少部分恢复SCI患者ANS系统中的一些功能失调活动。
