MNS: Median Nerve Stimulation Pilot
Study Details
Study Description
Brief Summary
Results from the University of Nottingham suggested that rhythmic median nerve stimulation (MNS) improves tic symptoms in Tourette syndrome (TS). The investigators will (1) provide a first replication of their study, (2) test the hypothesized electrophysiological mechanism and rule out a placebo effect as cause for the symptomatic benefit, and (3) gather information on the duration of effect after the end of stimulation and on individual characteristics that predict improvement with simulation. Completion of these Aims will give a clear go/no-go signal for a future clinical trial of chronic MNS delivered by a yet-to-be-developed wristwatch-style device.
NOTE: This study is not intended to evaluate a specific device for future use. Rather it is a study to determine the action of pulsed electrical stimulation on tic symptoms and to gain early evidence of effectiveness. This is a non-significant risk device study.
Condition or Disease | Intervention/Treatment | Phase |
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N/A |
Detailed Description
Chronic tic disorders (CTD), including Tourette syndrome (TS), are associated with a substantially reduced quality of life. Medication treatments are no more than 50-60% effective in randomized controlled trials, and are often discontinued due to unacceptable side effects. Behavioral therapies require ability to participate in therapy and a specially trained therapist, but weekly visits to psychologists are impractical for many Americans, especially in rural areas. Patients strongly desire new treatment options.
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. 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. 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.
The hypotheses of this project are that the tic benefits reported by the Nottingham investigators are replicable, that they are specific to rhythmic stimulation, which alone entrained cortical activity, rather than to a placebo effect, and that they endure past the end of stimulation.
This project (a) will replicate the Nottingham findings using identical methods, and (b) will test rhythmic MNS against a placebo treatment (arrhythmic MNS at the same mean frequency). It also will gather additional preliminary data needed for a future R01 application, including response and tolerability with longer (5-minute) stimulation blocks, and the duration of benefit after the end of a stimulation block.
Study Design
Arms and Interventions
Arm | Intervention/Treatment |
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Other: Experimental: rhythmic MNS, then arrhythmic MNS Participants will complete two stimulation sessions, at least a week apart. The first session involves rhythmic MNS and the second uses arrhythmic MNS. |
Device: Rhythmic median nerve stimulation
Square-wave 200 µs pulses triggered by computer at 12 Hz, at the threshold for thumb movement (expected ~2-15mA), applied to surface electrodes over the median nerve at the right wrist (conductive gel, 30 mm apart center-to-center, anode distal). This is a non-significant risk device study.
Other Names:
Device: Arrhythmic median nerve stimulation
Square-wave 200 µs pulses triggered by computer at random intervals with a mean rate of 12 Hz (as described in Morera Maiquez et al., 2020), at the threshold for thumb movement (expected ~2-15mA), applied to surface electrodes over the median nerve at the right wrist (conductive gel, 30 mm apart center-to-center, anode distal). This is a non-significant risk device study.
Other Names:
|
Other: Experimental: arrhythmic MNS, then rhythmic MNS Participants will complete two stimulation sessions, at least a week apart. The first session involves arrhythmic MNS and the second uses rhythmic MNS. |
Device: Rhythmic median nerve stimulation
Square-wave 200 µs pulses triggered by computer at 12 Hz, at the threshold for thumb movement (expected ~2-15mA), applied to surface electrodes over the median nerve at the right wrist (conductive gel, 30 mm apart center-to-center, anode distal). This is a non-significant risk device study.
Other Names:
Device: Arrhythmic median nerve stimulation
Square-wave 200 µs pulses triggered by computer at random intervals with a mean rate of 12 Hz (as described in Morera Maiquez et al., 2020), at the threshold for thumb movement (expected ~2-15mA), applied to surface electrodes over the median nerve at the right wrist (conductive gel, 30 mm apart center-to-center, anode distal). This is a non-significant risk device study.
Other Names:
|
Outcome Measures
Primary Outcome Measures
- Change in tic frequency from when MNS is turned off [During rhythmic MNS stimulation]
The number of tics per minute is assessed by an expert rater blind to condition and time point. A one-tailed t test will compare mean tic frequency in on vs. off 1-minute stimulation epochs on the rhythmic MNS day. This analysis replicates that of Study 3 in the Morera Maiquez et al 2020 citation. A secondary analysis will test for carryover effects.
- Change in tic severity from when MNS is turned off [During rhythmic MNS stimulation]
Severity is rated on a 5-point scale for each occurrence of any tic. The scale is the Intensity item from the Yale Global Tic Severity Scale [YGTSS], which uses integer scores from 0 (no tics) to 5 (severe intensity). A one-tailed t test will compare mean tic severity in on vs. off 1-minute stimulation epochs on the rhythmic MNS day. This analysis replicates that of Study 3 in the Morera Maiquez et al 2020 citation. A secondary analysis will test for carryover effects.
- Change in tic frequency during rhythmic MNS (vs. arrhythmic MNS) [During rhythmic MNS stimulation]
The number of tics per minute is assessed by an expert rater blind to condition and time point. Change in tic frequency from baseline (stimulation off) is compared between 5-minute MNS-on epochs on the rhythmic vs. the arrhythmic day. Subjects who do not complete both stimulation visits will not be included in this analysis. A repeated measures ANOVA will be used to compare effects of visit, order (rhythmic day first or second) and stimulation (on vs. off) on tic frequency. The hypothesized change is a significant interaction of visit, order and stimulation factors (p≤.05), showing greater improvement (off to on) with rhythmic vs. arrhythmic stimulation. This analysis includes the first six 5-minute blocks on each MNS day (i.e., the blocks that all participants complete).
- Change in tic severity during rhythmic MNS (vs. arrhythmic MNS) [During rhythmic MNS stimulation]
Overall tic severity for each 5-minute block is rated once on a 5-point scale by an expert blind to condition and time point. The scale is the Intensity item from the Yale Global Tic Severity Scale [YGTSS], which uses integer scores from 0 (no tics) to 5 (severe intensity). Change in tic severity from baseline (stimulation off) is compared between 5-minute MNS-on epochs on the rhythmic vs. the arrhythmic day. Subjects who do not complete both stimulation visits will not be included in this analysis. A repeated measures ANOVA will be used to compare effects of visit, order (rhythmic day first or second) and stimulation (on vs. off) on tic frequency and severity. The hypothesized change is a significant interaction of visit, order and stimulation factors (p≤.05), showing greater improvement (off to on) with rhythmic vs. arrhythmic stimulation. This analysis includes the first six 5-minute blocks on each MNS day (i.e., the blocks that all participants complete).
Secondary Outcome Measures
- Change in tic severity after MNS ends [up to 20 minutes after the end of stimulation at each study visit up to 1 month]
Duration of benefit will be estimated as follows. A repeated measures ANOVA will compare the change in tic frequency from baseline, during each 1-minute-long period following the end of stimulation. Here baseline means the tic frequency during the last 5 minutes of MNS from the same day.
- CGI-I, participant [5-25 minutes after the end of stimulation at each study visit up to 1 month]
Clinical Global Impression of Improvement (CGI-I), rated by participant. The CGI-I is a 7-point scale ranging from 1 = very much improved to 7 = very much worse.
- CGI-I, investigator [5-25 minutes after the end of stimulation at each study visit up to 1 month]
Clinical Global Impression of Improvement (CGI-I), rated by investigator. The CGI-I is a 7-point scale ranging from 1 = very much improved to 7 = very much worse.
- VAS rating of tic improvement [5-25 minutes after the end of stimulation at each study visit up to 1 month]
Participant rates overall tic improvement during active stimulation, from 0=no improvement to 100=complete remission of symptoms at some point, using a Visual Analog Scale (VAS).
- VAS rating of premonitory urge severity [Before MNS begins, at the end of each 5-min. MNS on or off block, and 5-25 minutes after the end of stimulation at each study visit up to 1 month]
Participant rates the maximal severity of any premonitory urges over the preceding minute, from 0=no premonitory urge to 100=maximally uncomfortable premonitory urge, using a Visual Analog Scale.
- VAS rating of discomfort [5-25 minutes after the end of stimulation at each study visit up to 1 month]
Participant rates peak discomfort experienced during the session, from 0=no discomfort to 100=maximal possible discomfort, using a Visual Analog Scale.
- Blindedness assessment [5-25 minutes after the end of stimulation at each study visit up to 1 month]
Participants guess whether they received the active or sham MNS condition, and rate their certainty for that guess on a 0-3 scale (0 = pure guess, 3 = certain).
Eligibility Criteria
Criteria
Inclusion Criteria:
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Age 15-64 inclusive at initial screening visit
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Informed consent by adult subject; assent by child and informed consent by guardian
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Current Tourette's Disorder or Persistent (Chronic) Tic Disorder according to the criteria in the Diagnostic and Statistical Manual of Mental Disorders, 5th Edition: DSM-5
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At least 1 tic per minute (average) during the first 5-min. baseline video session on the first visit (as scored during the session by the investigator)
Exclusion Criteria:
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Unable to complete study procedures for any reason
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Has an implanted device that could be affected by electrical current
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Pregnancy known to participant or (for children) to the parent
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Known or suspected primary genetic syndrome (e.g. Down syndrome, Fragile X)
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Intellectual disability (known, or likely from history and examination)
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Head trauma with loss of consciousness for more than 5 minutes
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Significant neurologic disease, not counting TS (exceptions include febrile seizures or uncomplicated migraine)
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Severe or unstable systemic illness
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Factors (such as exaggerated signs) that in the judgment of the principal investigator make the video recording or YGTSS an inaccurate assessment of tic severity
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Judged by investigator to be unlikely to complete study procedures or to return for later visits
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Change in somatic or psychotherapeutic treatment in the 2 weeks preceding the first stimulation visit
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Planned change in somatic or psychotherapeutic treatment between the 2 stimulation visits
Contacts and Locations
Locations
Site | City | State | Country | Postal Code | |
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1 | Washington University School of Medicine, Movement Disorders Center | Saint Louis | Missouri | United States | 63110 |
Sponsors and Collaborators
- Washington University School of Medicine
- National Center for Advancing Translational Science (NCATS)
Investigators
- Principal Investigator: Kevin J Black, MD, Washington University Medical School
Study Documents (Full-Text)
None provided.More Information
Additional Information:
Publications
- 202011092
- UL1TR002345