Effectiveness of STIL Orthosis in PD

Inclusion Criteria: * Participant is at least 18 years of age. * Willing to sign the informed consent. * Diagnosed with Parkinson's disease by a neurologist or movement disorders specialist. * Action tremor in one or two arms (clinical severity score of at least 2 on their dominant side, on MDS-UPDRS items 3.15 or 3.16). * At least experiencing wrist flexion/extension or forearm pronation/supination tremor. Exclusion Criteria: * Diagnosed with any other neurological disorder, such as epilepsy, Essential tremor, functional tremor, physiologic tremor, cerebellar tremor, MS, spasticity, ataxia, dystonia, Alzheimer's disease or dementia, atypical parkinsonism, peripheral neuropathy affecting the arms (e.g., carpal tunnel syndrome). * Disease duration of \> 15 years. * Experiencing severe bradykinesia/rigidity, to such an extent that the participant is unable to perform the ADL tasks (drinking, eating, pouring water). * Limited movement or muscle function in the arm/hand (for contractures or muscle diseases), or loss of muscle function in one arm (e.g., due to paralysis, or amputation). * Swollen, infected, inflamed areas, or skin eruptions, open wounds, or cancerous lesions of skin on the forearm or hand that would wear the orthosis during the clinical investigation. * Consuming excessive alcohol (more than 21 glasses per week for men and 14 glasses per week for women), as defined in the GGZ guidelines on alcohol use. * Having received a botulinum toxin injection to suppress h…