Comparative efficacy of different noninvasive brain stimulation therapies for recovery of global cognitive function, attention, memory, and executive function after stroke: a network meta-analysis of randomized controlled trials

BACKGROUND: Which noninvasive brain stimulation (NIBS) treatment – transcranial direct current stimulation (tDCS) or transcranial magnetic stimulation (TMS) – is more beneficial for stroke patients’ cognitive rehabilitation is still up for debate. OBJECTIVES: Our goal is to provide an overview of the research on the effectiveness and safety of various NIBS protocols. DESIGN: Systematic review and network meta-analysis (NMA) of randomized controlled trials (RCTs). METHODS: This NMA compared any active NIBS versus sham stimulation in adult stroke survivors to enhance cognitive function, with a focus on global cognitive function (GCF), attention, memory, and executive function (EF) using the databases MEDLINE, Embase, Cochrane Library, Web of Science, and ClinicalTrials.gov. The NMA statistical approach was built on a frequency framework. The effect size was estimated by the standardized mean difference (SMD) and a 95% confidence interval (CI). We compiled a relative ranking of the competing interventions based on their surface under the cumulative ranking curve (SUCRA). RESULTS: NMA showed that high-frequency repeated TMS (HF-rTMS) improved GCF compared with sham stimulation (SMD = 1.95; 95% CI: 0.47–3.43), while dual-tDCS improved memory performance versus sham stimulation significantly (SMD = 6.38; 95% CI: 3.51–9.25). However, various NIBS stimulation protocols revealed no significant impact on enhancing attention, executive function, or activities of daily living. There was no significant difference between the active stimulation protocols for TMS and tDCS and sham stimulation in terms of safety. Subgroup analysis demonstrated an effect favoring activation site of the left dorsolateral prefrontal cortex (DLPFC) (SUCRA = 89.1) for enhancing GCF and bilateral DLPFC (SUCRA = 99.9) stimulation for enhancing memory performance. CONCLUSION: The HF-rTMS over the left DLPFC appears to be the most promising NIBS therapeutic option for improving global cognitive performance after stroke, according to a comparison of numerous NIBS protocols. Furthermore, for patients with post-stroke memory impairment, dual-tDCS over bilateral DLPFC may be more advantageous than other NIBS protocols. Both tDCS and TMS are reasonably safe. REGISTRATION: PROSPERO ID: CRD42022304865