Open-label MNS for Tourette Syndrome
Condition: Tourette Syndrome; Tic Disorder, Chronic Motor or Vocal
MeSH terms: Tourette Syndrome; Tic Disorders; Syndrome
Study type: Interventional

Summary: 
      A recent report (Morera Maiquez et al 2020) described reduced tic severity in people with
      Tourette syndrome during 1-minute epochs of median nerve stimulation (MNS) at 10 Hz. Among
      the various questions still to be answered is the question of whether a device to administer
      MNS is practical for use in a chronic, real-world setting. This study will recruit
      participants who complete the clinic-based, blinded, randomized controlled trial,
      https://clinicaltrials.gov/ct2/show/NCT04731714, to determine the real-world usage and
      apparent utility of median nerve stimulation in people with chronic tics.
    

Detailed description: 
      Chronic tic disorders (CTD), including Tourette syndrome (TS), are associated with a
      substantially reduced quality of life (Evans et al 2016). Medication treatments are no more
      than 50-60% effective in randomized, controlled trials (RCTs), and are often discontinued due
      to unacceptable side effects (Thomas and Cavanna 2013). Behavioral therapies require ability
      to participate in therapy and a specially trained therapist (Scahill et al 2013), but weekly
      visits to psychologists are impractical for many Americans, especially in rural areas (Lin et
      al 2016). Patients strongly desire new treatment options (Cuenca et al 2015).

      In June, 2020, Stephen Jackson's group at the University of Nottingham published a
      fascinating report in Current Biology on a potential novel treatment for tics (Morera Maiquez
      et al 2020). The radical new idea arose from observations associating movement inhibition
      with 8-14 Hz activity in motor cortex. They first showed that rhythmic 12 Hz peripheral
      stimulation of the median nerve evoked synchronous contralateral EEG activity over primary
      sensorimotor cortex, whereas arrhythmic stimulation at the same mean rate did not. As
      hypothesized, median nerve stimulation (MNS) at 12 Hz created small but statistically
      significant effects on initiation of voluntary movements. Importantly, they also demonstrated
      that this stimulation did not meaningfully impair concentration, suggesting that the effect
      did not operate through simple distraction. They went on to test 10 Hz MNS in 19 TS patients,
      and demonstrated using blinded video ratings a significant reduction in tic number and
      severity during 1-minute stimulation epochs vs 1-minute no-stimulation epochs. They noted
      that in some participants, benefit lasted beyond the end of the stimulation epoch [personal
      correspondence]. Videos accompanying the publication showed dramatic benefit during MNS in
      some subjects. Although the authors appropriately noted the steps needed to generalize these
      results to clinical practice, news reports already have led a number of TS patients to
      contact them asking for treatment. The Nottingham group has referred such inquiries from the
      U.S. to me as leader of our Wash.U. Tourette Association of America (TAA) Center of
      Excellence.

      Among the various questions still to be answered is the question of whether such a device
      would be practical for use in the real world. This study will supply participants with a
      commercially available transcutaneous electrical nerve stimulation (TENS) units to use for
      median nerve stimulation as described in the Nottingham study. Participants will be told to
      use the device as much or as little as desired to see how such stimulation might be utilized
      in the real world.

      Here the investigators propose (a) to determine the real-world usage and apparent utility of
      stimulation in people with chronic tics, and (b) to determine momentary self-rated efficacy
      and side effects of stimulation. The investigators will also compare results from this study
      to those from the "Peripheral induction of inhibitory brain circuits to treat Tourette's:
      pilot" study, from which participants will be drawn, in order to compare laboratory and
      real-world efficacy.

      Aim 1. Determine the real-world usage and apparent utility of stimulation in people with
      chronic tics. Participants will be allowed to choose when and for how long to use the
      stimulation, thus simulating how patients would use the stimulation in their daily lives.

      Aim 2. Determine momentary self-rated efficacy and side effects of stimulation, using surveys
      taken at the beginning and end of stimulation periods, as well as twice daily when prompted.

      Aim 3. Compare results of this trial with those from "Peripheral induction of inhibitory
      brain circuits to treat Tourette's: pilot." Participants in this study will have been drawn
      from completers of the "peripheral induction" blinded RCT, allowing for clear comparisons
      between the laboratory conditions of the first study and the real-world conditions of the
      second.

      Completion of these Aims will provide practical information that can inform a future,
      controlled clinical trial of chronic MNS delivered by a portable device.
    

Intervention name(s): Active, self-directed electrical stimulation of the median nerve
Intervention type(s): Device
Intervention description(s): Electrical stimulation of the median nerve (12 Hz, pulse width 200µs), initially at the threshold needed to see movement of the right thumb with stimulation. After initial training with the device and education in the rationale for suprathreshold stimulation, participants will choose timing and intensity of stimulation based on their momentary symptom severity and their experience with the treatment since the beginning of the study. Participant can choose right or left median nerve (we will suggest their nondominant hand to minimize interference with daily activities).
Other intervention name(s): Rhythmic MNS
Intervention model: Single Group Assignment
Intervention model description: All participants will receive MNS at 12 Hz, pulse width 200µs. After initial threshold determination and training on device usage, individual participants will choose duration and intensity of treatment depending on their momentary symptom severity and history of response to treatment.
Masking: None (Open Label)
Primary purpose: Treatment
Keywords: Tourette; tic; Transcutaneous Electric Nerve Stimulation; Median Nerve