Are transcranial brain stimulation effects long-lasting in post-stroke aphasia? A comparative systematic review and meta-analysis on naming performance

In the last decade, the effects of NIBS on language recovery in post-stroke aphasia have been evaluated, but little is known about the long-term effectiveness. To this aim, we conducted a systematic review and meta-analysis to determine whether positive effects, mainly on naming performance, are maintained in time, and rTMS and/or tDCS (either as an add-on therapy to SLT or as monotherapy) can be considered effective and reliable interventions for naming rehabilitation. Sixteen studies met our inclusion criteria and the pooled SMDs showed a medium to large rTMS effect and a small to medium tDCS effect. Critically, the treatment effects were maintained in time. Sub-analyses indicated that while rTMS can be considered effective for both subacute and chronic patients, tDCS seems adequate only for chronic aphasia. Importantly, the level of evidence as qualified with GRADE was moderate to high for rTMS and low for tDCS studies.