Intrinsic auricular muscle zone stimulation for Parkinson disease: The EARSTIM-PD Phase II multi-center pilot study results

•Pilot studies have suggested that intrinsic auricular muscle zone (IAMZ) stimulation alleviates PD motor features longer than the duration of stimulation.•A multicenter, double-blinded, active sham-controlled pilot trial was conducted to evaluate the safety and dose-response-time curve of the Earstim device in PD patients experiencing OFF periods.•Earstim was well-tolerated.•At 60 min after treatment onset, motor improvement peaked on IAMZ treatments compared to active sham.•The short stimulation (20-min) IAMZ treatment had the largest aggregate motor score improvement. IAMZ treatments resulted in motor improvements greater than the minimum clinically important difference at multiple time points, whereas active sham treatment did not.