Multi-session transcutaneous auricular vagus nerve stimulation for Parkinson's disease: evaluating feasibility, safety, and preliminary efficacy

Abstract

BackgroundIn pre-clinical animal models of Parkinson's disease (PD), vagus nerve stimulation (VNS) can rescue motor deficits and protect susceptible neuronal populations. Transcutaneous auricular vagus nerve stimulation (taVNS) has emerged as a non-invasive alternative to traditional invasive cervical VNS. This is the first report summarizing the safety, feasibility, and preliminary efficacy of repeated sessions of taVNS in participants with PD.ObjectivesTo evaluate the feasibility, safety, and possible efficacy of taVNS for motor and non-motor symptoms in mild to moderate PD.MethodsThis is a double-blind, sham controlled RCT (NCT04157621) of taVNS in 30 subjects with mild to moderate PD without cognitive impairment. Participants received 10, 1-h taVNS sessions (25 Hz, 200% of sensory threshold, 500 μs pulse width, 60 s on and 30 s off) over a 2-week period. Primary outcome measures were feasibility and safety of the intervention; secondary outcomes included the MDS-UPDRS, cognitive function and self-reported symptom improvement.ResultstaVNS treatment was feasible, however, daily in-office visits were reported as being burdensome for participants. While five participants in the taVNS group and three in the sham group self-reported one or more minor adverse events, no major adverse events occurred. There were no group differences on blood pressure and heart rate throughout the intervention. There were no group differences in MDS-UPDRS scores or self-reported measures. Although global cognitive scores remained stable across groups, there was a reduction in verbal fluency within the taVNS group.ConclusionstaVNS was safe, and well-tolerated in PD participants. Future studies of taVNS for PD should explore at-home stimulation devices and optimize stimulation parameters to reduce variability and maximize engagement of neural targets.

Left Vagus Stimulation Modulates Contralateral Subthalamic β Power Improving the Gait in Parkinson's Disease

“…However, even if the therapeutic usefulness of taVNS is still questionable, our results show early proofs of neural engagement. 27,28 With the current methodology it is not possible to draw any further conclusion on the association between gait speed changes and β power. Indeed, the latter is an acknowledged biomarker of bradykinesia and rigidity and of their modulation through therapies, 29 and its relationship with gait is controversial.…”

Unraveling the threads of stability: A review of the neurophysiology of postural control in Parkinson's disease

“…Subsequent research has focused on this region primarily for transcutaneous vagal nerve stimulation (tVNS), thought to affect activity in the nucleus tractus solitarus and locus coeruleus, which relay afferent sensory information via connections to the thalamus, orbitofrontal cortex, and medulla [ 131 , 132 ]. Multiple recent studies found tVNS improved various gait parameters in people with PD, including those with FoG, however, had mixed success in improving UPDRS III scores [ [133] , [134] , [135] , [136] , [137] ]. While these results suggest its promise in treating gait impairments in PD, tVNS’ effects on PIGD symptoms remain relatively unknown.…”