The Efficacy and Safety of Transcutaneous Auricular Vagus Nerve Stimulation for Depression in PD

Participants in the Experimental group underwent fourteen consecutive daily sessions of transcutaneous auricular vagus nerve stimulation (taVNS, twice daily, 30 minutes each time) , whereas participants in the sham stimulation group underwent fourteen consecutive daily sessions of sham taVNS. Assessments of depression symptoms, motor symptoms were performed three times: at baseline, one day post intervention and 2 weeks post intervention. The cortical activity (using Functional near-infrared spectroscopy) were assessed at baseline, one day post intervention.

Inclusion criteria

This study recruited right-handed subjects from the Department of Neurology, Huai'an Second People's Hospital. The inclusion criteria for patients with PD and depression were as follows: diagnosis of idiopathic Parkinson's disease based on the clinical diagnostic criteria of the Movement Disorder Society; diagnosis of depressive disorder in accordance with the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5), with a Hamilton Depression Rating Scale (HAMD) score ≥ 8; stable medication regimens for Parkinson's disease for at least one month prior to enrollment; aged 40 to 80 years; and voluntary participation with written informed consent. In addition, age- and gender-matched non-depressed PD patients and healthy controls were enrolled to further compare brain functional characteristics among different groups.

Exclusion criteria

presence of cognitive impairment defined as a Montreal Cognitive Assessment (MoCA) score < 23; ongoing use of antidepressant medications; presence of contraindications related to transcutaneous auricular vagus nerve stimulation (taVNS); receipt of vagus nerve stimulation (VNS) treatment within the past month; and comorbid severe neurological, renal, cardiovascular or hepatic diseases.