Feasibility, safety, and preliminary efficacy of transcutaneous auricular vagus nerve stimulation to improve cognitive function in patients with spinal cord injury: a pilot, randomized, controlled trial

Cognitive impairment is common yet underrecognized in patients with spinal cord injury (SCI), compromising functional recovery and quality of life. Evidence for effective treatments specifically targeting cognitive function after SCI remains limited. This study aimed to evaluate the efficacy and safety of transcutaneous auricular vagus nerve stimulation (taVNS) for cognitive impairment in patients with SCI. We conducted a randomized, controlled, observer-blinded pilot trial including 42 subacute SCI patients with cognitive impairment. All participants received standard rehabilitation therapy and were randomized to taVNS (active) or sham groups, 30 min twice daily, 5 days/week for 4 weeks. The primary outcome was cognitive function measured by the Montreal Cognitive Assessment (MoCA). Secondary outcomes included the performance in the Color-Word Stroop Task and the Visuospatial N-back Task, Spinal Cord Independence Measure III (SCIM-III), and Pain Rating Index (PRI). Feasibility was assessed using recruitment, retention, and intervention adherence rates. Safety was assessed by treatment-emergent adverse events. Thirty-four patients were included in the final analysis. The taVNS group showed greater improvement in MoCA scores ( p = .004) and a higher proportion achieving the MCID ( p = .012). Exploratory analyses suggested improvements in executive control, visuospatial memory, and mobility. Improvements in the MoCA visuospatial and delayed recall scores were associated with reduced pain and greater functional independence, respectively. No adverse events occurred. taVNS is safe, feasible, and potentially effective for cognitive impairment after SCI, with possible benefits across executive and visuospatial domains. Larger samples are needed to confirm efficacy and explore multidomain improvements. This study has been registered on the Chinese Clinical Trial Registry with the identifier ChiCTR2400081166.