Efeito da estimulação transcraniana por corrente contínua e treinamento físico sobre o desempenho neuromuscular e cardiopulmonar de pacientes hemiparéticos crônicos por AVC: um ensaio clínico randomizado controlado

Abstract

Stroke survivors often exhibit impaired voluntary motor control, which negatively impacts on their physical capacity. Interventions that stimulate neuroplasticity and improve physical fitness are essential for the rehabilitation of these patients. The aim of this PhD thesis was to evaluate the chronic effect of transcranial direct current stimulation (tDCS), associated with physical training, on the neuromuscular and cardiopulmonary performance of chronic hemiparetic subjects after stroke. Twenty-three participants with 56 ± 9 years of age, and 10 to 96 months after stroke were enrolled in the study. Initially, the functional impairment was assessed [Fugl-Meyer (FM), Berg and 10-m walk-tests]. After being matched for their motor function, patients were randomly assigned to tDCS (experimental) or Sham (control) groups. Outcomes included: a) maximal force [isometric maximum peak torque of knee extension (PT-Ext) and flexion (PT-Flx)]; b) cardiopulmonary exercise testing on treadmill [(maximum oxygen uptake (VO2max) and at the ventilatory threshold (VO2-VT); maximum work capacity (Wmax) and at the ventilatory threshold (WVT)]. Subsequently, patients underwent 24 sessions of tDCS [real or placebo (Sham)] combined with individualized multimodal physical training performed twice a week. To quantify the effects of the intervention, baseline evaluations were repeated after 12 (post-12) and 24 (post-24) sessions. The outcomes were compared between groups at baseline (BL) by t-test for independent samples. In order to quantity the chronic effect of the intervention, the relative change (Δ%) from BL to post-12 and post-24 were compared by means of 2-way repeated measures ANOVA followed by Fisher post hoc tests. The effect size was calculated by Cohen's d. At post-12, the tDCS group showed significant improvements compared to Sham for PT-Ext of the paretic limb (25.9±25.3% vs. 5.6±13.1%), VO2max (25.9±25.3% vs. 5.6±13.1%), VO2-VT (25.9±25.3% vs. 5.6±13.1%), Wmax (25.9±25.3% vs. 5.6±13.1%), and WVT (25.9±25.3% vs. 5.6±13.1%). These differences remained in post-24 for PT-Ext of the paretic limb (25.6±12.6% vs. -6.7±20.3%). Finally, the motor function expressed by FM showed greater increase in post-24 vs. post-12 only for the tDCS group (57.9±68.2% vs. 42.9±52.6%). In conclusion, post-stroke chronic patients with motor impairments, submitted to tDCS combined with multimodal physical training, exhibited greater improvements in muscle strength, oxygen uptake, work capacity and motor function than those who performed isolated physical training.