Respiratory-gated Transcutaneous Auricular Vagus Nerve Stimulation for Improving Apathy in Parkinson's Disease

Real RAVANS was performed on the cymba conchae of left ear in the vicinity of the auricular branch vagus nerve according to the Participant's respiratory rhythm. Stimulation parameters: frequency = 100 Hz; pulse width = 200 us, once a day, 30 minutes each time, one second of stimulation occurs during exhalation.

Sham RAVANS was performed on on the cymba conchae of left ear according to the Participant's respiratory rhythm. Stimulation parameters: frequency = 100 Hz; pulse width = 200 us, once a day, 30 minutes each time, one second of stimulation occurs during exhalation and the interval between stimulus is 29 seconds.