Multimodal physical training combined with tDCS improves physical fitness components in people after stroke: a double-blind randomized controlled trial

ABSTRACTABSTRACTBackground Transcranial direct current stimulation (tDCS) seems to be a potential tool to optimize the long-term effects of multimodal physical training (MPT) on fitness components in post-stroke patients.Objective We investigated the effects of cortical tDCS combined with MPT on motor function reflected by strength, motor performance, and cardiorespiratory capacity in chronic stroke patients.Methods This double-blind randomized controlled trial included 18 volunteers (55 ± 10 y, 72 ± 13 kg), who underwent MPT preceded by either sham stimulation (SHAM) or 2 mA bi-hemispheric tDCS. MPT consisted of 24 sessions of 60–70 min performed 2 d/wk within 12–16 weeks, with individualized intensity. Outcomes were Fugl-Meyer scores for lower limbs (FM-LL), and total (FM-Total); speed in the 10-m walk test (10MWT); oxygen uptake and work output at maximal effort (VO2max and Wmax), and gas exchange threshold (VO2-GET and W-GET); peak torque of isokinetic knee extension (PT-EXT) and flexion (PT-FLEX) of paretic and non-paretic limbs; bilateral strength deficit during knee extension (DS-EXT) and flexion (DS-FLEX).Results Pre- vs. post-intervention improvements were detected in tDCS vs. SHAM (p < 0.05) for FM-total (29.6% vs. 15.9%; effect size [ES] = 0.78), FM-LL (35.9% vs. 9.0%; ES = 1.23), 10MWT (10.6% vs. 3.8%; ES = 0.67), Wmax (75.0% vs. 4.3%; ES = 1.68), W-GET (91.6% vs. 12.4%; ES = 1.62), PT-EXT (25.6% vs. −6.5%; ES = 1.94) and PT-FLEX (26.3% vs. 9.8%; ES = 0.65) of the paretic limb, and DS-EXT (−13.7% vs. 2.5; ES = 1.43).Conclusion Bi-hemispheric cortical tDCS optimized the effects of MPT performed with moderate volume and intensity upon muscle strength, motor function, and cardiorespiratory performance in stroke hemiparetic survivors. (Registration number RBR-22rh3p).KEYWORDS: Cerebrovascular accidentneuromodulationfunctional capacitybrain stimulationexercisehealth AcknowledgmentsWe thank the patients for their participation in the study. The authors disclose the following financial support: CNPq (process 303629/2019-3, recipient PF), FAPERJ (process E-26/202.880/2017, recipient PF; process E-26/202.705/2019, recipient FC), and CAPES (process 1427841, recipient RM). The funders had no role in the study design, data collection, analysis, decision to publish, or preparation of the manuscript.Disclosure statementNo potential conflict of interest was reported by the authors.Author contributionsRM, FAC, and PF contributed to the study conception, design and management, data interpretation and analysis, literature search, and drafting of the manuscript. RM, RAM, and WB were involved in the recruitment of participants, data collection, and interpretation. GF, WB, and FAC reviewed the draft version and provided intellectual input in writing the final version of the manuscript. PF was the principal investigator supervising all the experimental procedures and manuscript preparation, also providing lab resources and financial support for the project. All authors have read and approved the final version of the manuscript, and agree with their presentation order.Additional informationFundingThe work was supported by the CAPES [1427841]; CNPQ [403206/2021-9]; CNPQ [303629/2019-3]; FAPERJ [E-26/200.817/2021]; FAPERJ [E-26/202.705/2019]; FAPERJ [E-26/211.210/2021].