Design and validation of a closed-loop, motor-activated auricular vagus nerve stimulation (MAAVNS) system for neurorehabilitation.

BACKGROUND: Studies have found that pairing vagus nerve stimulation (VNS) with motor activity accelerates cortical reorganization. This synchronous pairing may enhance motor recovery. OBJECTIVE: To develop and validate a motor-activated auricular vagus nerve stimulation (MAAVNS) system as a potential neurorehabilitation tool. METHODS: We created MAAVNS and validated its function as part of an ongoing clinical trial investigating whether taVNS-paired rehabilitation enhances oromotor learning. We compared 3 different MAAVNS EMG electrode configurations in 3 neonates. The active lead was placed over the buccinator muscle. Reference lead placements were orbital, temporal or frontal. RESULTS: The frontal reference lead produced the highest sensitivity (0.87 ± 0.07 (n = 8)) and specificity (0.64 ± 0.13 (n = 8)). Oral sucking reliably triggers MAAVNS stimulation with high confidence. CONCLUSION: EMG electrodes placed on target orofacial muscles can effectively trigger taVNS stimuli in infants in a closed loop fashion.