Overview

Growing evidence suggests that vagal nerve stimulation (VNS) may be novel and effective in the management of the symptom burden of multiple sclerosis (MS) potentially by reducing inflammation and emotional distress, therefore improving overall well-being.

We will complete a pilot study comparing transcutaneous auricular vagus nerve stimulation (taVNS) and transcutaneous cervical vagus nerve stimulation (tcVNS) to a standard intervention of dorsolateral prefrontal cortex (DLPFC) transcranial direct current stimulation (tDCS) as an active control. The primary outcome will be feasibility and the preliminary efficacy data concerning self-reported symptom reduction to inform the design of an intervention, and estimated power needed to complete a larger sham-controlled RCT. We will also measure heart rate variability (HRV), an easily obtained biomarker of vagus nerve stimulation (VNS), in correspondence to intervention response.

Eligibility

Inclusion Criteria:

• Female
• Age 25-65 years (inclusive)
• Definite diagnosis of MS or related demyelinating disorders (e.g., Neuromyelitis Optica or NMO)
• Stable high efficacy DMT ≥ 6 months before enrollment and throughout the trial
• PDDS score ≤ 6 (established to be able to complete procedures)
• SymptoMScreen Score ≥12
• WRAT-5 ≥85
• SDMT z-score > -3.0
• K10 < 35
• Stable disease activity, defined as being more than 1 month after a clinical relapse or confirmed radiologic disease activity, or more than 1 month after steroid treatment
• Ability to use mobile devices

Exclusion Criteria:

• Primary neurologic disorder other than MS and related demyelinating disorders like NMO (e.g., stroke, Parkinson's disease, spinal cord injury, intracranial mass, traumatic brain injury (TBI), epilepsy, mild cognitive impairment (MCI), or dementia), psychiatric disorders or major medical disorders (e.g., history of myocardial infarction, diabetes, thyroid disease, arrhythmia, atrial fibrillation)
• Diagnosis of Postural Orthostatic Tachycardia Syndrome (POTS)
• History of vagus nerve surgery/vagotomy
• History of diagnosed cardiovascular disease, a heart transplant, presence of permanent pacemaker implant or Left Ventricular Assist Device
• Use of certain medications that can affect heart rate variability, such as beta-blockers, calcium channel blockers, and cardiac glycosides
• Use of SP1 inhibitor medications such as Fingolimod, Siponimod, Ozanimod, and Ponesimod
• Nicotine use in the past 6 months (smoking/vaping)
• Pregnant or planning pregnancy during the study period or breastfeeding
• Seizure disorder or recent (<5 years) seizure history
• Active ear infections or ear pathology
• Current presence of implanted vagus nerve stimulator or any other active implanted electronic devices (e.g., pacemaker, defibrillators, cochlear implants, DBS, iVNS, etc.)
• Presence of metal objects in the head/neck
• Any skin disorder or skin sensitive area near stimulation locations
• BMI ≥ 35