Acute Effect of Transcutaneous Auricular Vagus Nerve Stimulation on the Functional Capacity of Active Community-dwelling Women Elderly: A Randomized, Blinded Crossover Pilot Study

Research Objectives: To evaluate the effect of Transcutaneous Auricular Vagus Nerve Stimulation (tNVS) on the functional capacity of community-dwelling elderly individuals.

Design: A Randomized, Blinded Crossover Pilot Study

Setting: Community Elderly Reference Center

Participants: 17 active women elderly volunteers (67 ± 4 years) from de single center were underwent auricular vagus nerve, with the stimulation site randomly selected using opaque paper, with a 24-hour interval between active and active sham stimulation sessions.

Interventions: Active tNVS stimulation was applied to the cymba conchae of the left ear using a protocol of 25Hz, 500μs, 30s on, 60s off, adjusted to sensory threshold intensity (below the pain threshold) for 30 minutes. Active sham stimulation was applied to the earlobe of the right ear, devoid of vagal pathways, using the same protocol.

Main Outcome Measures: Immediately after stimulation, participants performed the 6-minute walk test (6MWT) following American Thoracic Society guidelines. The analyzed outcomes included walked meters and predicted walked meters. Statistical analysis employed paired t student test and accepting p< 0.05.

Results: Participants showed increased functional capacity as indicated by the percentage of predicted walked meters (Sham: 93 ± 14%; Stimulation: 100 ± 15%; mean difference: -7.2%; p< 0.01, Cohen’s D: 0.65), but no difference in walked meters (Sham: 422 ± 66m; Stimulation: 442 ± 57m; mean difference: -20.4m; p=0.07, Cohen’s D: 0.43). Furthermore, no alterations in blood pressure, heart rate, or subjective perception of effort were observed between stimulation and sham stimulation during the 6MWT.

Conclusions: Stimulation may be an important tool to facilitate motor gains and improve functional capacity in active elderly individuals, suggesting its potential as an adjunctive therapy in rehabilitation for conditions such as frailty syndrome, and chronic cardiovascular and pulmonary diseases.

Author(s) Disclosures: All authors denied conflicts of interests.