Noninvasive neuromodulation for disorders of consciousness: an updated systematic review and meta-analysis

BACKGROUND: Despite advances in noninvasive neuromodulation for disorders of consciousness (DoC), the available evidence is inconclusive. We sought to elucidate the efficacy and safety of these interventions for DoC. METHODS: statistic. The quality of evidence was performed using the Grade approach. RESULTS: We included 24 studies and six studies (147 participants) provided data for meta-analysis. The methodological quality was good for all trials according to the PEDro scale, while most studies (18 out of 24 studies, 75%) were rated high risk of bias by the RoB 2 tool. For efficacy, the effect of rTMS (g = 0.49, 95% CI = 0.01, 0.98) and TNS (g = 0.59, 95% CI = 0.08, 1.10) for DoC compared with sham stimulation was medium, while tDCS was not more effective than sham control. No difference was found for dropout in TNS or rTMS compared with sham control. CONCLUSIONS: Our findings provide evidence that rTMS and TNS showed more positive effects for DoC, while tDCS was no better than sham stimulation. While, due to the small number of patients in the different studies, the small number of studies and potential risk of bias in the meta-analysis, robust evidence of noninvasive neuromodulation for patients with DoC is lacking. These findings highlight the importance of precision in targeting noninvasive neuromodulation for patients with DoC, RCTs with high-quality methodological design, conduct and reporting. Trial registration PROSPERO Identifier: CRD42024499177. Registered 20 January 2024.