Theraputic Effects of Brain-Computer Interface on Motor Recovery of Stroke Patients: A Meta-analysis

Background Previous clinical studies have demonstrated the effects of brain-computer interface (BCI) on the motor recovery of stroke patients. The aim of this study was to evaluate the therapeutic effects of BCI on improving motor functions of stroke patients. Methods We conducted a meta-analysis on randomized controlled trials (RCTs) on BCI training for post-stroke motor rehabilitation. Relevant publications were identified from the databases of PubMed, Embase, ScienceDirect, and Cochrane Library. The standardized mean difference (SMD) with 95% confidence intervals (CI) were calculated as the pooled effect size of the motor outcome. Results Thirty-five of the 43 candidate articles involving 749 participants were included in this meta-analysis. Overall, both the significant immediate effect size of 0.53 and long-lasting effect size of 0.26 were found for motor outcome measured by Fugl-Meyer Assessment. A further subgroup-analysis observed larger therapeutic effects on lower-limb than upper-limb. A subgroup-analysis also indicated that stroke patients may gain better functional outcome in the subacute phase than in the chronic phase. Superior effect of BCI training was also detected for distal function of upper-limb over proximal function. BCI training combined with functional electrical stimulation (FES) was more effective than BCI combined with robot. No significant effect was found in other combined interventional methods, especially the use of transcranial direct current stimulation, which cannot potentiate the effects of BCI training. In addition, subgroup-analysis also indicated a greater effect for longer durations of intervention. And the dosage between 15 min and 180 min was found to be optimal. Conclusions BCI has significant immediate and long-lasting effects on improving motor function of both upper-limb and lower-limb of stroke patients. Superior therapeutic could be delivered to patients in the subacute phase and clearer benefits are evident in distal functions of upper extremity. When combined with FES, BCI seems to be more effective than when combined with robot and other external devices. Longer durations of intervention could provide better effects. But bigger is not always better for weekly dosage. ### Competing Interest Statement The authors have declared no competing interest. ### Funding Statement This work was supported by the National Natural Science Foundation of China (NSFC, No. 82172540). ### Author Declarations I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained. Yes The details of the IRB/oversight body that provided approval or exemption for the research described are given below: NO. I confirm that all necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived, and that any patient/participant/sample identifiers included were not known to anyone (e.g., hospital staff, patients or participants themselves) outside the research group so cannot be used to identify individuals. Yes I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance). Yes I have followed all appropriate research reporting guidelines, such as any relevant EQUATOR Network research reporting checklist(s) and other pertinent material, if applicable. Yes Data available on request from the authors.