Median Nerve Stimulation for Tourette Syndrome and Chronic Tic Disorder
Condition: Tourette Syndrome; Chronic Tic Disorder
MeSH terms: Tourette Syndrome; Tics; Tic Disorders; Syndrome
Study type: Interventional

Summary: 
      Tourette syndrome (TS) and chronic tic disorder (CTD) are neurodevelopmental disorders that
      impact approximately 1% of 5-18 year olds worldwide. Both TS and CTD are characterised by the
      presence of tics, which are repetitive, purposeless, movements or vocalisations of short
      duration which can occur many times throughout a day. Tics can have a significant negative
      impact on daily functioning and quality of life, hence, many seek out approaches to manage
      and reduce their tics and the urges people with TS or CTD often feel preceding them. The two
      main evidence-based approaches to treating tics are behavioural therapies and medication;
      both of which can be effective, but accessibility and waitlists are often an issue for
      behavioural therapies and side effects are common with medication use. Consequently, there is
      an urgent need for the development of alternative, safe and accessible treatments.

      This study aims to examine the effects of rhythmic pulses of electrical stimulation delivered
      to the wrist in treating tics in people with TS and CTD. In recent work, the investigators
      have shown that this type of electrical stimulation known as median nerve stimulation (MNS),
      can substantially reduce tics and related urges during stimulation. The investigators now
      want to extend this work to examine the effects of the stimulation on a higher number of
      people, compared to placebo and treatment as usual. The investigators will do this through
      assessment of symptom change using questionnaires, interviews and videos collection during
      four weeks of stimulation and two time points afterwards.

      The investigators have developed a new MNS device for this trial which is portable and easy
      to use. The primary hypothesis is that active rhythmic MNS will lead to a reduction in tic
      severity compared to a placebo condition. The secondary hypothesis is that MNS will also have
      a positive beneficial effect on urges, impairment, well-being and co-occurring
      Obsessive-Compulsive Disorder (OCD) symptoms compared to both sham stimulation and no
      stimulation.
    

Detailed description: 
      The symptoms of Tourette Syndrome (TS) (tics and premonitory urges) can be treated using
      behavioural therapies and/or medications, however access, availability, side effects and
      treatment resistance are factors which many people with TS and their family's express
      frustration with. Therefore, it is in the interest of patients and the wider medical
      community that alternative treatments are tested and scientifically validated. In recent
      work, the investigators have found that low intensity electrical stimulation delivered to the
      wrist can be effective in significantly reducing tics and tic related premonitory urges. In
      the study the investigators want to expand this work to examine the effects of the
      stimulation on a higher number of people, compared to placebo and treatment as usual and to
      examine the suitability of a wearable device for delivering stimulation from home.

      The investigators will conduct a parallel, double-blind, placebo-controlled trial of a
      wearable, wrist-worn, therapeutic device for the suppression of premonitory urge and the
      reduction of tics in individuals with TS. In order to validate the device as a genuine and
      effective form of therapy, it is essential that a placebo branch of the study is completed.
      Participants will be made aware of the three different experimental arms ahead of enrolment
      and will be debriefed following completion of the trial. The investigators are committed to
      clearly explaining why a placebo condition is essential, while minimising the amount of
      information the investigators withhold from participants, hence the investigators feel it is
      important to be able to let participants know the condition participants were in at the end
      of the trial.

      The device the investigators are aiming to trial will be programmed to deliver low-intensity
      (1-19 mA) rhythmic (10Hz) trains of electrical stimulation to the median nerve for 14
      minutes, and will be used by each participant from home once each day, 5 days each week, for
      a period of 4 weeks. Participants assigned to the active condition will experience rhythmic
      (10Hz) trains of stimulation set to an individual intensity which the investigators have
      found to be effective in the investigators' previous work (-120% of intensity needed to
      generate a visible muscle twitch in the thenar muscle). Those assigned to the placebo group
      will receive stimulation at a subthreshold rate (50% intensity needed to generate thenar
      muscle twitch). The investigators' previous work suggests that this serves as a sufficient
      control condition. Those in the waitlist group would receive treatment as normal, prior to an
      open label phase of receiving active stimulation.

      A total of 135 participants (45 per group) will be allocated to one of the three groups;
      active stimulation; sham stimulation; or waitlist (i.e., treatment as usual). In order to
      minimise the difference in age, gender and symptom severity between groups, the investigators
      will perform a stratified randomisation for age, gender and severity (using Yale Global Tic
      Severity Scale (YGTSS) Total Tic Severity Score) to allocate individuals to each group.

      The effects of the stimulation will be assessed using several semi-structured interviews,
      questionnaire measures and video recordings of participant's tics. The investigators will
      also use questionnaire measures/ interviews to measure baseline characteristics of the
      participants, as these factors may influence response to the investigators proposed
      intervention. The majority of this trial will be remotely supervised and therefor the
      majority of these measures will also be taken through video call and online questionnaire
      measures with the exception of an initial visit to the University of Nottingham.

      The primary hypothesis is that active MNS will lead to a reduction in tic severity compared
      to subthreshold placebo stimulation. The procedure for testing this will be as follows:

        1. Participants who have expressed an interest in the study will be given a detailed
           participant information sheet. Participants will be given the opportunity to ask
           questions about the study. If participants wish to proceed and to have an initial
           telephone screening to assess eligibility participants will then be asked to complete an
           initial consent form which will asked for their consent to take part in the screening
           and for the research team to keep a record of their answers during that process.

        2. Consenting participants will then be contacted by a member of the research team at an
           agreed time via telephone/video call. This call should last no longer than an hour. This
           will be used to give participants further insights into the trial and to establish trial
           eligibility. Trial eligibility will be assessed according to the investigators'
           predefined inclusion/ exclusion criteria. The YGTSS, semi structured interview will also
           be conducted by a trained member of the research team to establish If the potential
           participant has enough tics to be eligible for the trial.

        3. After completing the telephone screening, eligible participants will be sent a further
           electronic consent form to take part in the rest of the trial. After obtaining consent,
           participants will be allocated into a trial arm and a date will be set for them to visit
           Nottingham. In the case of the wait list group participants will not visit Nottingham
           until participants have entered into the open label active phase of the trial.

        4. During the baseline visit to the University of Nottingham, participants will receive the
           stimulation device and will be trained in its correct placement and use. In order to
           ensure participant's comfort with the stimulation, a practice session will be performed.
           If the participant experiences significant discomfort, participants will be withdrawn
           from the trial. On the same day, demographic information along with primary and
           secondary measures will be collected using various questionnaires and structured
           interviews. Participants in the waitlist group will also complete these measurements
           online and through video call.

        5. Participants in the active and placebo groups will return home with the device and be
           instructed to commence stimulation sessions on the following Monday. Participants will
           be asked to use the device once each day, 5 days each week, for a period of 4 weeks.
           During the stimulation period participants will be asked to complete a few short
           questions each day which should take 1-2 minutes. Participants will also be contacted by
           a member of the research team at weeks 1, 2, 3 and 4 of stimulation and 3 and 6 months
           after completing stimulation. During these meetings through video call lasting
           approximately 1 hour various semi-structured interviews and questionnaires will be
           administered to assess changes in symptoms. A subset of participants will also be asked
           to record videos of themselves 5 minutes before the stimulation, during the stimulation
           and 5minutes after the stimulation and to upload these to a secure online platform.
           These will be used by the research team to objectively count changes in tics.

      The investigators estimate that the trial will take 9 months to collect all data sets,
      including the 6 month follow up period. Visits to Nottingham will take place during the first
      3 months of the trial.
    

Intervention name(s): Active stimulation; Sham stimulation
Intervention type(s): Device; Device
Intervention description(s): Participants assigned to the active stimulation arm will receive rhythmic MNS 2 minutes on and 1 minute off for 15 minutes. The strength of the stimulation will be set to 120% the intensity needed to produce a visible contraction within the thenar muscle.; Participants assigned to the sham stimulation arm will receive rhythmic MNS 2 minutes on and 1 minute off for 15 minutes. The strength of the stimulation will be set to 50% the intensity needed to produce a visible contraction within the thenar muscle.
Allocation: Randomized
Intervention model: Parallel Assignment
Intervention model description: Participants will be randomly allocated into three groups (ratio: 1:1:1): active stimulation, sham stimulation and waitlist (no stimulation).
Those in the waitlist group would receive treatment as normal, prior to an open label phase of receiving active stimulation.
Masking: Quadruple (Participant, Care Provider, Investigator, Outcomes Assessor)
Primary purpose: Treatment
Keywords: Tourette Syndrome; Median nerve stimulation; Chronic Tic Disorder