Inclusion Criteria:  18-80 years old and able to provide informed consent Have a diagnosis of idiopathic PD made by a movement disorders specialist Medically optimized without planned medication changes for the duration of the study • Resting tremor subscore >/= 2 of the most-affected arm on the Movement Disorders Society Unified Parkinson's Disease Rating Scale (MDS-UPDRS) item 2.10 Postural tremor subscore >/= 1 of the most-affected arm on the MDS-UPDRS item 3.15 Signed informed consent  Exclusion Criteria:  The presence of additional neurologic diseases that might confound testing or the coexistence of PD and essential tremor together (action tremor that was present prior to the development of parkinsonism) Moderate to severe peripheral neuropathy (reduced vibratory sensation) at the upper extremities, quantified with a graduated tuning fork Montreal cognitive assessment (MoCA) score < 20 or previously documented dementia Unable to walk without walking aid