Clinical Trials

Inclusion Criteria:

• Must be ≥21 years of age.
• Must be approved for DBS surgery at Mayo Clinic for treatment of essential tremor.
• Competent and willing to provide signed, informed consent to participate in the study.
• Stable dose of tremor medications, if applicable, for 30 days prior to study entry.
• Stable dose of antidepressant medications, if applicable, for 90 days prior to study entry.
• Willing to comply with study protocol requirements including:
  • Remaining on a stable dosage of tremor and antidepressant medications, if applicable, during the duration of the study;
  • No significant alcohol or caffeine consumption within 8 hours of study visits;
  • No usage of the Cala TWO device within 8 hours of study visits;
  • Women of child-bearing potential must be willing to have a pregnancy test within 48 hours of the optional PET/CT exams.
• Competent and willing to provide written, informed consent to participate in the study.
• To be enrolled in the optional PET/CT study the subject must be enrolled in the Cala TWO study and meet all of the inclusion criteria and none of the exclusion criteria of that study.

Exclusion Criteria: 

• Moderate to severe ethanol dependence as defined by the criteria outlined in the DSM-5 (score of 4 or higher).
• Implanted electrical medical device, such as a pacemaker, defibrillator, or deep brain stimulator.
• Previous thalamotomy procedure, including stereotactic thalamotomy, gamma knife radiosurgical thalamotomy, and focused ultrasound for the treatment of tremor.
• Suspected or diagnosed epilepsy or other seizure disorder.
• Swollen, infected, inflamed areas, or skin eruptions, open wounds, or cancerous lesions of skin at stimulation site (wrist).
• Peripheral neuropathy affecting the tested upper extremity.
• Presence of any other neurodegenerative disease like Parkinson plus syndromes suspected on neurological examination. These include: multisystem atrophy, progressive supranuclear palsy, dementia with Lewy bodies, and Alzheimer’s disease.
• Anyone suspected to have the diagnosis of idiopathic Parkinson’s disease (PD). This includes excluding anyone with the presence of parkinsonian features including bradykinesia rigidity, or postural instability. Subjects who exhibit only mild resting tremor but no other symptoms or signs of PD may be included.
• 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 Principal Investigator.
• Significant alcohol or caffeine consumption within 8 hours of study enrollment, which may confound the results of the study, where significant caffeine is considered more than 95 mg (equivalent to a cup of coffee), and significant alcohol is considered more than 14 g (equivalent to 5 oz of wine, 12 oz of beer, or 1.5 oz of distilled spirits).
• Subjects unable to communicate with the investigator and staff.
• Any health condition that in the investigator's opinion should preclude participation in this study.
• Pregnancy or anticipated pregnancy during the course of the study.
• Subjects will excluded from the optional PET/CT study if they have one or more of the following conditions:
  • Subjects unable to lie down without moving for 15 minutes;
  • Subjects whose glucose tests >=200 mg/dL prior to the PET/CT exams;
  • Women of child-bearing potential showing a negative pregnancy test within 48 hours of the PET exams;
  • Claustrophobic patients unable to tolerate the PET/CT scans (no sedation can be offered).