Research on the Brain Mechanism of taVNS in Regulating PD Motor Symptoms

Research on the Brain Mechanism of Transcutaneous Auricular Vagus Nerve Stimulation in Regulating PD Motor Symptoms

This study is a double blind comparative study exploring the neural underpinnings of taVNS modulating PD motor deficits. We hypothesize that taVNS might improve PD motor deficits by regulating the balance between excitation and inhibition in the primary motor cortex.

Patients in the Experimental group underwent fourteen consecutive daily sessions of transcutaneous auricular vagus nerve stimulation (taVNS, twice daily, 30 minutes each time) , whereas patients in the sham stimulation group underwent fourteen consecutive daily sessions of sham taVNS with the electrodes were fixed at the left earlobe . Assessments of motor symptoms and cortical activity (using Functional near-infrared spectroscopy and Transcranial magnetic stimulation) were performed two times: at baseline, one day post intervention.

Inclusion Criteria:

• (1) had a diagnosis of idiopathic PD according to the Movement Disorder Society Clinical Diagnostic Criteria for PD and ON-medication Hoehn and Yahr (H&Y) stage ≤2,
• (2) had stable pharmacotherapy for PD at least one month prior to the study,
• (3) were aged between 40 and 80,
• (4) signed written informed consent,
• (5) can cooperate with the testing and taVNS treatment.

Exclusion Criteria:

• (1) with cognitive impairment, according to Montreal Cognitive Assessment (MOCA) < 24;
• (2) with severe tremor or levodopa-induced dyskinesia;
• (3) with current intake of anticholinergics or any drugs that could induce cerebral functional change;
• (4) with taVNS contraindications;
• (5) received VNS treatment during the past six month;
• (6) with concomitant severe neurologic, renal, cardiovascular, or hepatic disease.