Clinical Trial: Responsive Deep Brain Stimulator for Essential Tremor

Study Status: Recruiting
Recruit Status: Recruiting
Study Type: Interventional

Official Title: Closing the Loop on Tremor: A Responsive Deep Brain Stimulator for the Treatment of Essential Tremor

Brief Summary: Essential tremor is an incurable, degenerative brain disorder that results in increasingly debilitating tremor, and afflicts an estimated 7 million people in the US. In one study, 25% of essential tremor patients were forced to change jobs or take early retirement because of tremor. Essential tremor is directly linked to progressive functional impairment, social embarrassment, and even depression. The tremor associated with essential tremor is typically slow, involves the hands (and sometimes the head and voice), worsens with intentional movements, and is insidiously progressive over many years. Deep brain stimulation has emerged as a highly effective treatment for intractable, debilitating essential tremor. However, since the intention tremor of essential tremor is typically intermittent, and commonly absent at rest, the currently available continuous deep brain stimulation may be delivering unnecessary current to the brain that increases undesirable side effects such as slurred speech and walking difficulty, and hastens the depletion of device batteries, necessitating more frequent surgical procedures to replace spent pulse generators. The overall objective of this early feasibility study is to provide preliminary data on the safety and efficacy of "closed-loop" deep brain stimulation for intention tremor using novel deep brain stimulation devices capable of continuously sensing brain activity and delivering therapeutic stimulation only when necessary to suppress tremor.

Detailed Summary:

The purpose of this study is to investigate brain signals related to intention tremor in essential tremor in order to deliver deep brain stimulation only when the patient is showing symptoms. By delivering stimulation only when needed, the investigators hypothesize that the treatment will be more effective, will cause fewer adverse side effects and will increase battery time of the device (reducing the number of battery replacement surgeries).

Participation in this study will require extensive pre-surgical screening to determine eligibility for deep brain stimulation surgery, a deep brain stimulation surgical procedure, and regular follow-ups. Subjects will be seen monthly post surgery for 6 months. After 6 months, data will be assessed and closed-loop deep brain stimulation may be offered as a stimulation setting. If so, the stimulator settings will be changed from chronic to responsive. If not, the subject will continue to receive chronic deep brain stimulation stimulation. Subsequent visits will be scheduled every 6 months until a total of 24 months of study participation (also at month 9).

At the end of the initial 24-month study period, subjects will have the choice of 1) continuing active stimulation at the current setting, 2) continuing stimulation but searching for a new setting, 3) discontinuing stimulation (turning the device off), 4) having the device removed. If the subject continues to receive active stimulation, they will be followed by the investigators and seen at yearly intervals.

Sponsor: University of Florida

Current Primary Outcome:

• Clinical Rating Scale for Tremor (CRST) for continuous deep brain stimulation [ Time Frame: 6 months post-surgery ]

  - Reduction in Clinical Rating Scale for Tremor after 6 months as an effect of continuous Vim deep brain stimulation

  The Fahn-Tolosa-Marin Tremor Rating Scale is a clinical rating scale assessing severity of tremor by body part from 0 (none) to 4 (severe). The scale is divided into three parts, where Part A assesses tremor severity at rest, during posture, and kinetic maneuvers for nine body parts; Part B assesses ability to perform specific motor tasks/functions (writing, drawing, and pouring with dominant and nondominant hands); and Part C assesses patient-reported functional disability resulting from the tremor. Score ranges from 0 to 80 for Part A, from 0 to 36 for Part B, and from 0 to 28 for Part C. The total score obtained by adding the three parts is 144. A higher score indicates a higher severity of the tremor. Finally, the scale includes one separate item dealing with global assessment of tremor-related disability, rated by both patient and examiner on a 5-point scale.

• Clinical Rating Scale for Tremor (CRST) for closed-loop deep brain stimulation [ Time Frame: Baseline until 24 months post-surgery ]

  - Closed-loop deep brain stimulation as an effective alternative to continuous deep brain stimulation

  Clinical scores during continuous stimulation will be compared to scores on the during closed-loop stimulation.

• Clinical Rating Scale for Tremor (CRST) for continuous deep b
  
  

  Original Primary Outcome: Same as current
  
  

  Current Secondary Outcome:
  
  

  Original Secondary Outcome:
  
  Information By: University of Florida
  

  Dates:
  Date Received: January 6, 2016
  Date Started: February 1, 2017
  Date Completion: November 2021
  Last Updated: February 22, 2017
  Last Verified: February 2017