Efficacy of median nerve electrical stimulation on the recovery of patients with consciousness disorders: a systematic review and meta-analysis

OBJECTIVE: To identify whether median nerve stimulation (MNS) may be a potential candidate for the treatment of consciousness disorders via a systematic review and meta-analysis. METHODS: PubMed, Cochrane Library, China National Knowledge Infrastructure, Chinese VIP Information, Wanfang, and SinoMed databases were searched. Risk of bias was assessed using the Cochrane Collaboration’s tool. The Glasgow Coma Scale (GCS), Disability Rating Scale (DRS), electroencephalogram (EEG), days in the Intensive Care Unit (ICU), and cerebral blood flow measures were compared between the median nerve stimulation and control groups. The meta-analysis was conducted using Review Manager software. RESULTS: We identified 2244 studies, of which 23 (with data from 1856 patients) qualified for the analysis. MNS improved GCS scores (mean difference [MD] = 2.15), EEG scores (MD = 1.61), cerebral mean blood flow velocity (MD = 4.23), and cerebral systolic blood flow velocity (MD = 10.51). Furthermore, it decreased DRS scores (MD = −1.77) and days in the ICU (MD = −2.02). The effects of MNS on GCS scores increased with longer treatments (1 week, MD = 1.03; 1 month, MD = 2.35) and were better with right MNS (right, MD = 2.36; bilateral, MD = 1.72). CONCLUSIONS: MNS may promote recovery from consciousness disorders.