Transcranial direct current stimulation (tDCS) for improving aphasia after stroke: a systematic review with network meta-analysis of randomized controlled trials.

The primary functional communication result rested on only 3 studies with 112 participants. The review reports 493 participants in the qualitative analysis but 471 participants in the summary of main findings. Included study sample sizes ranged from 3 to 74, with a median of 13. Many included trials were small and heterogeneous in current, number of sessions, electrode location, time since stroke, and concurrent therapy. Risk of bias was unclear, and adverse event reporting was often unsatisfactory. Some outcomes lacked closed loops, so parts of the analysis were adjusted indirect comparisons rather than full multiple treatment comparisons. The analysis focused on post-intervention effects and did not show whether benefits last.

The paper states there was no funding source. It does not provide a separate author conflict-of-interest declaration.

Do not conclude that tDCS improves everyday communication after stroke. The primary outcome, functional communication, showed no evidence of effect, and the positive finding was limited to naming nouns compared with sham. Also, trials varied in concurrent rehabilitation, so tDCS cannot be isolated as the cause.