Transcranial direct current stimulation combined with robotic therapy for upper and lower limb function after stroke: a systematic review and meta-analysis of randomized control trials

Abstract

Background Transcranial direct current stimulation (tDCS) is a non-invasive brain stimulation method able to modulate neuronal activity after stroke. The aim of this systematic review was to determine if tDCS combined with robotic therapy (RT) improves limb function after stroke when compared to RT alone. Methods A search for randomized controlled trials (RCTs) published prior to July 15, 2021 was performed. The main outcome was function assessed with the Fugl-Meyer motor assessment for upper extremities (FM/ue) and 10-m walking test (10MWT) for the lower limbs. As secondary outcomes, strength was assessed with the Motricity Index (MI) or Medical Research Council scale (MRC), spasticity with the modified Ashworth scale (MAS), functional independence with the Barthel Index (BI), and kinematic parameters. Results Ten studies were included for analysis (n = 368 enrolled participants). The results showed a non-significant effect for tDCS combined with RT to improve upper limb function [standardized mean difference (SMD) = − 0.12; 95% confidence interval (CI): − 0.35–0.11)]. However, a positive effect of the combined therapy was observed in the lower limb function (SMD = 0.48; 95% CI: − 0.15–1.12). Significant results favouring tDCS combined with RT were not found in strength (SMD = − 0.15; 95% CI: − 0.4–0.1), spasticity [mean difference (MD) = − 0.15; 95% CI: − 0.8–0.5)], functional independence (MD = 2.5; 95% CI: − 1.9–6.9) or velocity of movement (SMD = 0.06; 95% CI: − 0.3–0.5) with a “moderate” or “low” recommendation level according to the GRADE guidelines. Conclusions Current findings suggest that tDCS combined with RT does not improve upper limb function, strength, spasticity, functional independence or velocity of movement after stroke. However, tDCS may enhance the effects of RT alone for lower limb function. tDCS parameters and the stage or type of stroke injury could be crucial factors that determine the effectiveness of this therapy.

Safety and effects of transcranial direct current stimulation on hand function in preschool children with hemiplegic cerebral palsy: A pilot study

“…Conversely, the Melbourne Assessment 2 and the Selective Control of the Upper Extremity Scale might be less sensitive. Secondly, for the Modified Ashworth Scale, a single anodal tDCS might produce no effect on muscle tone, which was consistent with previous study (Comino-Suárez et al, 2021).…”

Transcranial direct current stimulation (tDCS) modulates motor execution in a limb reaching task

“…Here, we investigated how tDCS can modify a tradeoff action in the lower limb. A comparison with the literature on healthy volunteers is not feasible as most of the studies have focused on stroke (Bai et al, 2022;Comino-Su arez et al, 2021), multi-limb coordination (Leenus et al, 2015) and Parkinson's disease (Lee et al, 2019). Therefore, our data must be taken with caution and confirmed by future studies, this anodal excitement would open up new scenarios in medical practices that involve brain stimulation.…”

Improving Upper Limb and Gait Rehabilitation Outcomes in Post-Stroke Patients: A Scoping Review on the Additional Effects of Non-Invasive Brain Stimulation When Combined with Robot-Aided Rehabilitation

“…This NIBS-dependent bihemispheric effect was originally proven in experimental models employing intracortical microstimulation, achieving a rapid cortical reorganization of motor representation [ 89 ]. In addition, there is robust evidence that cortical stimulation can modulate cortical excitability and the motor responses evoked from the stimulated cortex, increase the dendritic density in the stimulated cortex, favor the reorganization of representational maps in the stimulated cortex, and lead to the synchronization and spreading of the perilesional neuronal activity supporting a major rewiring of far-to-distant connections, including transcallosal loops [ 16 , 21 , 90 , 91 , 92 , 93 , 94 , 95 , 96 ].…”

“…The usefulness of conjugating both approaches stems from the idea that targeting the plasticity mechanisms mentioned above in a very specific manner, i.e., by providing cortical stimuli (top-down approaches) that focus on the effects of bottom-up approaches, could result in a significant enhancement of the plasticity-dependent recovery mechanisms and, eventually, motor function recovery. Some trials aimed to demonstrate the usefulness of these combined approaches concerning both upper and lower limb motor function recovery [ 3 , 9 , 14 , 21 , 22 , 23 , 24 ]. However, conclusive data on the efficacy of NIBS and RAR in combination is still missing.…”