The Effectiveness of Noninvasive Brain Stimulation Techniques Combined With Motor Interventions in Adult Patients After Stroke: An Overview of Systematic Reviews

Objective: This study aimed to provide an overview of systematic reviews (SRs) about the effectiveness of combining noninvasive brain stimulation (NIBS) techniques with rehabilitation in adult patients with stroke. Materials and Methods: The overview protocol has been prospectively registered on the International Prospective Register of Systematic Reviews (CRD42021241226). Eight electronic databases were searched from inception to December 2023. SRs investigating the effectiveness of NIBS techniques in addition to motor interventions compared with sham stimulation and the same motor interventions in adults with stroke were included. The methodologic quality of the included SRs was assessed using A MeaSurement Tool to Assess systematic Reviews-2. The certainty of the evidence was evaluated through the Grading of Recommendations Assessment, Development, and Evaluation approach. Results: This overview included 13 SRs (85 primary studies, 2768 participants): Nine focused on arm and six on gait rehabilitation. The quality of the included SRs was low or critically low. The included SRs reported a high clinical heterogeneity for NIBS techniques and protocols or motor rehabilitation. Of the 42 outcomes assessed, two (4.7%) were judged as high-certainty evidence and referred to the lack of superiority of combining NIBS, especially transcranial direct current stimulation, with arm robotics for improving arm function. Moreover, 21 outcomes (50%) were judged as low-certainty evidence; they highlighted the way NIBS combined with rehabilitation can positively affect several functional domains. Conclusions: Even if no firm conclusions can be derived from the available literature owing to the quality of the included SRs and the heterogeneity of NIBS techniques and additional motor rehabilitation, some clinical indications have been provided.