Tommaso Schirinzi

Should we be stimulating the old vagus nerve (e.g. VNS) to steady movement and quiet inflammation in Parkinson’s and beyond? How about a 2025 update? The vagus nerve is the major parasympathetic highway linking brainstem nuclei to body organs and it can be electrically stimulated to modulate circuits involved in movement, mood and immune system tone. Proietti and colleagues describe in a new paper just published in Movement Disorders how invasive and non-invasive vagus nerve stimulation may treat Parkinson’s and other movement disorders by tuning brain networks and possibly calming inflammation. Key Points: - The evidence for the vagus nerve approach spans many diseases including Parkinson’s tremor, cervical dystonia and Tourette. - There are signals for possible motor and nonmotor improvement using vagus stimulation. - Vagus nerve stimulation (VNS) engages multiple transmitters (brain chemicals) including GABA, norepinephrine and acetylcholine. - VNS may possibly reduce neuroinflammation while enhancing plasticity. - Transcutaneous auricular VNS has shown promise as a potentially safer and more scalable option. My take: I am less confident that the author’s that VNS is ready for prime time as an add on strategy if you have persistent Parkinson’s symptoms (e.g. gait freezing, tremor, anxiety or GI issues). I do think VNS for movement disorders is promising and should be in used in the context of a research study. Here are 5 interesting points that resonated w/ me about this paper. 1- Non-invasive ear or neck stimulation is different from deep brain stimulation (DBS). 2- Non-invasive stimulation is largely designed to nudge circuits rather than to ablate or directly pace deep targets. 3- Early trials have shown improved step length, gait stability and sometimes tremor improvement w/ taVNS (ear based) or tcVNS (neck based), however the effects have varied across studies. 4- Safety has been reasonable w/ only mild skin or autonomic sensations in many reports, although long term outcomes will still require more rigorous tracking. 5- The field critically needs bigger as well as sham-controlled trials w/ clear dosing schedules. It sure would be helpful to have an electrical (bio)marker like STN beta power! movementdisorders.onlinelibr… @FixelInstitute @ParkinsonDotOrg @MDCP_Journal @movedisorder