*2.1. Participants*

Twenty PD patients (12 females, 8 males; age 67.2 ± 9.1 years; height 1.65 ± 0.12 m; body mass 67.3 ± 13.1 kg; Hoehn-Yahr stage III, 10 with diagnosis of freezing) participated in the study. All patients were in ON state of Levodopa treatment during the assessment. The study was approved by the local scientific committee and institutional review board (Comitato Etico Interaziendale delle Provincie di Lecco, Como, Sondrio, Italy), and was in accordance with the Code of Ethics of the World Medical Association (Declaration of Helsinki, 1967). A complete explanation of the study protocol was provided to the patients, who signed a written informed consent before their participation in the study. This trial was registered on ClinicalTrials.gov NCT03015714.
