Demonstrate safety and effectiveness of symptomatic action tremor relief in the treated hand following stimulation with the Cala Trio System using the Trio+ bands as compared to the Trio bands in adults with Essential Tremor (ET) and/or Parkinson's Disease (PD) over 2 weeks.

20 patients with (13 with ET and 7 with PD) with at least mild postural tremor were enrolled in a prospective, single-center, two-arm, crossover study that took place over the course of four weeks. TAPS devices were shipped to patients to run the study remotely. In the first arm of the study, subjects received TAPS treatment using the original. Cala Trio band for two weeks. Followed by a wash-out period (> 24 hours), subjects entered the second arm and received TAPS using the Trio+ band for an additional two weeks. Unsupervised motion assessments were captured at home, and at the beginning and end of the four weeks by telemedicine.

Inclusion Criteria:

• Must be ≥22 years of age
• Competent and willing to provide written, informed consent to participate in the study
• Willing to comply with study protocol requirements

For subjects with Essential Tremor:

• A diagnosis of essential tremor
• A tremor severity score of 2 or above in the dominant hand/arm as measured by one of the TETRAS upper limb postural tremor items
• No significant alcohol intake within 8 hours prior to study visits

For subjects with Parkinson's Disease:

• Dominant hand/arm exhibiting postural tremor ≥ 2 (while in the off state) as assessed by the MDS-UPDRS postural tremor score
• Stable dose of Parkinson's disease medications, if applicable, for 30 days prior to study entry

Exclusion Criteria:

• Implanted electrical medical device, such as a pacemaker, defibrillator, or deep brain stimulator
• Suspected or diagnosed epilepsy or other seizure disorder
• Any skin condition at the stimulation site that in the investigator's opinion should preclude participation in this study
• Diagnosed with peripheral neuropathy affecting the tested upper extremity
• Presence of any other neurodegenerative disease other than essential tremor or Parkinson's Disease
• Subjects unable to communicate with the investigator and staff
• Any health condition or concomitant medication that in the investigator's opinion should preclude participation in this study
• Pregnancy or anticipated pregnancy during the course of the study
• Botulinum toxin injection for hand tremor within 6 months prior to study enrollment
• Are participating or have participated in another interventional clinical trial in the last 30 days which may confound the results of this study, unless approved by the Sponsor