The adjunct of transcranial direct current stimulation to Robot-assisted therapy in upper limb post-stroke treatment

Transcranial direct current stimulation (TDCS) and robot-assisted therapy (RAT) proved to be promising interventions in post-stroke rehabilitation. However, the effects of combining the two treatments are not significantly clear. To determine the effects of combined therapy using transcranial direct current stimulation (tDCS) with robot-assisted therapy (RAT) in the impairment of the upper limb in stroke rehabilitation. The Cochrane Library, MEDLINE, Embase, Google Scholar, and Trial Registries were systematically searched for randomised controlled trials in May 2020. As the outcome, the Fugl-Meyer Assessment score (FMS) was used. A pairwise and a network meta-analysis were performed. 5 RCTs with RAT versus RAT + tDCS groups and 21 RCTs with RAT versus the control group with 892 people were analysed. Of these studies, 10 RCTs evaluated acute-subacute (<8 weeks) people, while 16 chronic people. By analysing the FMS with a pair-wise meta-analysis, we demonstrate significant improvements only in the RAT alone compared to the control (acute-subacute, SMD:4.09 (1.31, 6.87) and chronic, SMD:2.22 (0.99, 3.45)). Instead, performing a network meta-analysis, through an analysis of the surface under the cumulative ranking curve (SUCRA) we report a ranking of the effectiveness of the interventions. We assess SUCRA in acute-subacute stroke: Control:0.23, RAT + tDCS:0.31, RAT:0.96 and in chronic stroke: Control:0.06, RAT + tDCS:0.62, RAT:0.82. RAT is, respectively, 96% and 82% likely to be the best-ranked treatment. Despite the limitations, this network meta-analysis appears to demonstrate through the rank of interventions that adding tDCS to RAT is not useful in upper-limb stroke rehabilitation.