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Iverson AM, Arbuckle AL, Ueda K, Song DY, Bihun EC, Koller JM, Wallendorf M, Black KJ. Median Nerve Stimulation for Treatment of Tics: Randomized, Controlled, Crossover Trial. J Clin Med 2023; 12:2514. [PMID: 37048598 PMCID: PMC10095326 DOI: 10.3390/jcm12072514] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2023] [Revised: 03/09/2023] [Accepted: 03/13/2023] [Indexed: 03/29/2023] Open
Abstract
A prior study showed that rhythmic, but not arrhythmic, 12 Hz stimulation of the median nerve (MNS) entrained the sensorimotor cortex EEG signal and found that 10 Hz MNS improved tics in Tourette syndrome (TS). However, no control condition was tested, and stimulation blocks lasted only 1 min. We set out to replicate the TS results and to test whether tic improvement occurs by the proposed cortical entrainment mechanism. Preregistration was completed at ClinicalTrials.gov, under number NCT04731714. Thirty-two people with TS, age 15-64, completed two study visits with repeated MNS on and off blocks in random order, one visit for rhythmic and one for arrhythmic MNS. Subjects and staff were blind to order; a video rater was additionally blind to stimulation and to the order of visits and blocks. Rhythmic MNS at 10 Hz improved tics. Both rhythmic and arrhythmic 12 Hz MNS improved tic frequency, intensity, and urges, but the two treatments did not differ significantly. Participant masking was effective, and there was no carryover effect. Several participants described a dramatic benefit. Discomfort was minimal. There was no evidence that the MNS benefit persisted after stimulation ended. These results replicate the tic benefit from MNS but show that the EEG entrainment hypothesis cannot explain that benefit. Another electrophysiological mechanism may explain the benefit; alternatively, these data do not exclude a placebo effect.
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Affiliation(s)
- Ann M. Iverson
- Washington University School of Medicine, Washington University in St. Louis, St. Louis, MO 63110, USA
| | - Amanda L. Arbuckle
- Department of Psychiatry, Washington University in St. Louis, St. Louis, MO 63110, USA
| | - Keisuke Ueda
- Department of Neurology, Washington University in St. Louis, St. Louis, MO 63110, USA
| | - David Y. Song
- University of Rochester School of Medicine and Dentistry, Rochester, NY 14642, USA
| | - Emily C. Bihun
- Department of Psychiatry, Washington University in St. Louis, St. Louis, MO 63110, USA
| | - Jonathan M. Koller
- Department of Psychiatry, Washington University in St. Louis, St. Louis, MO 63110, USA
| | - Michael Wallendorf
- Division of Biostatistics, Institute for Informatics, Washington University in St. Louis, St. Louis, MO 63110, USA
| | - Kevin J. Black
- Departments of Psychiatry, Neurology, Radiology, and Neuroscience, Washington University in St. Louis, St. Louis, MO 63110, USA
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Beeler P, Jensen NO, Kim S, Robichaux-Viehoever A, Schlaggar BL, Greene DJ, Black KJ, Chakrabarty RK. Fractality of tics as a quantitative assessment tool for Tourette syndrome. J R Soc Interface 2022; 19:20210742. [PMID: 35193387 PMCID: PMC8864347 DOI: 10.1098/rsif.2021.0742] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
Tics manifest as brief, purposeless and unintentional movements or noises that, for many individuals, can be suppressed temporarily with effort. Previous work has hypothesized that the chaotic temporal nature of tics could possess an inherent fractality, that is, have neighbour-to-neighbour correlation at all levels of timescale. However, demonstrating this phenomenon has eluded researchers for more than two decades, primarily because of the challenges associated with estimating the scale-invariant, power law exponent—called the fractal dimension Df—from fractional Brownian noise. Here, we confirm this hypothesis and establish the fractality of tics by examining two tic time series datasets collected 6–12 months apart in children with tics, using random walk models and directional statistics. We find that Df is correlated with tic severity as measured by the YGTTS total tic score, and that Df is a sensitive parameter in examining the effect of several tic suppression conditions on the tic time series. Our findings pave the way for using the fractal nature of tics as a robust quantitative tool for estimating tic severity and treatment effectiveness, as well as a possible marker for differentiating typical from functional tics.
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Affiliation(s)
- Payton Beeler
- Center for Aerosol Science and Engineering, Department of Energy, Environmental and Chemical Engineering, Washington University in St Louis, St Louis, MO 63110, USA
| | - Nicholas O Jensen
- Computational and Systems Biology Program, Division of Biology and Biomedical Sciences, Washington University in St Louis, St Louis, MO 63110, USA
| | - Soyoung Kim
- Department of Psychiatry, Washington University School of Medicine, St Louis, MO 63130, USA
| | | | - Bradley L Schlaggar
- Kennedy Krieger Institute, Baltimore, MD 21205, USA.,Departments of Neurology and Pediatrics, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Deanna J Greene
- Department of Cognitive Science, University of California San Diego, La Jolla, CA 92093, USA
| | - Kevin J Black
- Department of Psychiatry, Washington University School of Medicine, St Louis, MO 63130, USA.,Department of Neurology, Washington University School of Medicine, St Louis, MO 63130, USA.,Department of Radiology, Washington University School of Medicine, St Louis, MO 63130, USA.,Department of Neuroscience, Washington University School of Medicine, St Louis, MO 63130, USA
| | - Rajan K Chakrabarty
- Center for Aerosol Science and Engineering, Department of Energy, Environmental and Chemical Engineering, Washington University in St Louis, St Louis, MO 63110, USA.,Institute for Public Health, Washington University in St Louis, St Louis, MO 63110, USA
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Black KJ, Kim S, Schlaggar BL, Greene DJ. The New Tics study: A Novel Approach to Pathophysiology and Cause of Tic Disorders. JOURNAL OF PSYCHIATRY AND BRAIN SCIENCE 2020; 5:e200012. [PMID: 32587895 PMCID: PMC7316401 DOI: 10.20900/jpbs.20200012] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
We report on the ongoing project "The New Tics Study: A Novel Approach to Pathophysiology and Cause of Tic Disorders," describing the work completed to date, ongoing studies and long-term goals. The overall goals of this research are to study the pathophysiology of Provisional Tic Disorder, and to study tic remission (or improvement) in a prospective fashion. Preliminary data collection for the project began almost 10 years ago. The current study is nearing completion of its third year, and has already reported several novel and important results. First, surprisingly, at least 90% of children who had experienced tics for only a mean of 3 months still had tics at the 12-month anniversary of their first tic, though in some cases tics were seen only with remote video observation of the child sitting alone. Thus almost all of them now had a DSM-5 diagnosis of Tourette's Disorder or Persistent (Chronic) Tic Disorder. Baseline clinical features that predicted 12-month outcome included tic severity, subsyndromal autism spectrum symptoms, an anxiety disorder, and a history of 3 or more phonic tics. Second, we found that poorer tic suppression ability when immediately rewarded for suppression predicted greater tic severity at follow-up. Third, striatal volumes did not predict outcome as hypothesized, but a larger hippocampus at baseline predicted worse severity at follow-up. Enrollment and data collection continue, including functional connectivity MRI (fcMRI) imaging, and additional analyses are planned once the full sample is enrolled.
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Affiliation(s)
- Kevin J. Black
- Departments of Psychiatry, Neurology, Radiology and Neuroscience, Washington University in St. Louis School of Medicine, St. Louis, MO 63110, USA
| | - Soyoung Kim
- Departments of Psychiatry and Radiology, Washington University in St. Louis School of Medicine, St. Louis, MO 63110, USA
| | - Bradley L. Schlaggar
- Kennedy Krieger Institute, Baltimore, MD 21205; and Departments of Neurology and Pediatrics, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA
| | - Deanna J. Greene
- Departments of Psychiatry and Radiology, Washington University in St. Louis School of Medicine, St. Louis, MO 63110, USA
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Kim S, Greene DJ, Robichaux-Viehoever A, Bihun EC, Koller JM, Acevedo H, Schlaggar BL, Black KJ. Tic Suppression in Children With Recent-Onset Tics Predicts 1-Year Tic Outcome. J Child Neurol 2019; 34:757-764. [PMID: 31241402 PMCID: PMC6733613 DOI: 10.1177/0883073819855531] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Successful voluntary tic suppression is a key component of the behavioral interventions that are used to treat tic disorders. This study aimed to examine tic suppression in children with recent-onset tics and determine whether the capacity to suppress tics predicts future tic severity. We tested 45 children (30 male, mean age 7.74 years) with recent-onset tics (mean 3.47 months prior to the first study visit; baseline) and re-examined each child at the 12-month anniversary of the first recognized tic (follow-up). At the baseline visit, children performed a tic suppression task with several conditions: tic freely, inhibit tics given a verbal request, and inhibit tics in the presence of a reward. At the baseline visit, children with tics for only a few months could suppress their tics, and tic suppression was especially successful when they received an immediate and contingent reward. Additionally, the ability to suppress tics in the presence of a reward predicted tic severity at follow-up. These findings suggest that better inhibitory control of tics within months of tic onset may be an important predictor of future tic symptom outcome.
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Affiliation(s)
- Soyoung Kim
- Department of Psychiatry, Washington University School of Medicine, United States
| | - Deanna J. Greene
- Department of Psychiatry, Washington University School of Medicine, United States
- Department of Radiology, Washington University School of Medicine, United States
| | | | - Emily C. Bihun
- Department of Psychiatry, Washington University School of Medicine, United States
| | - Jonathan M. Koller
- Department of Psychiatry, Washington University School of Medicine, United States
| | - Haley Acevedo
- Department of Psychiatry, Washington University School of Medicine, United States
| | - Bradley L. Schlaggar
- Kennedy Krieger Institute, Baltimore, MD, United States
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD, United States
- Department of Pediatrics, Johns Hopkins University School of Medicine, Baltimore, MD, United States
| | - Kevin J. Black
- Department of Psychiatry, Washington University School of Medicine, United States
- Department of Radiology, Washington University School of Medicine, United States
- Department of Neurology, Washington University School of Medicine, United States
- Department of Neuroscience, Washington University School of Medicine, United States
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The urge to blink in Tourette syndrome. Cortex 2019; 120:556-566. [PMID: 31525588 DOI: 10.1016/j.cortex.2019.07.010] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2019] [Revised: 05/06/2019] [Accepted: 07/12/2019] [Indexed: 12/13/2022]
Abstract
Functional neuroimaging studies have attempted to explore brain activity that occurs with tic occurrence in subjects with Tourette syndrome (TS). However, they are limited by the difficulty of disambiguating brain activity required to perform a tic, or activity caused by the tic, from brain activity that generates a tic. Inhibiting ticcing following the urge to tic is important to patients' experience of tics and we hypothesize that inhibition of a compelling motor response to a natural urge will differ in TS subjects compared to controls. This study examines the urge to blink, which shares many similarities to premonitory urges to tic. Previous neuroimaging studies with the same hypothesis have used a one-size-fits-all approach to extract brain signal putatively linked to the urge to blink. We aimed to create a subject-specific and blink-timing-specific pathophysiological model, derived from out-of-scanner blink suppression trials, to eventually better interpret blink suppression fMRI data. Eye closure and continuously self-reported discomfort were reported during five blink suppression trials in 30 adult volunteers, 15 with a chronic tic disorder. For each subject, data from four of the trials were used with an empirical mathematical model to predict discomfort from eye closure observed during the remaining trial. The blink timing model of discomfort during blink suppression predicted observed discomfort much better than previously applied models. Combining this approach with observed eye closure during fMRI blink suppression trials should therefore extract brain signal more tightly linked to the urge to blink. The simple mean of time-discomfort curves from each subject's other trials also outperformed older models. The TS group blinked more than twice as often during the blink suppression block, and reported higher baseline discomfort, smaller excursion from baseline to peak discomfort during the blink suppression block, and slower return of discomfort to baseline during the recovery block.
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Abstract
Exposure and response prevention (ERP) is a first-line behavior therapy for obsessive-compulsive disorder, and has also been tested in Tourette syndrome (TS). However, ERP for tic disorders requires intentional tic suppression, which for some patients is difficult even for brief periods. Additionally, practical access to behavior therapy is difficult for many patients, especially those in rural areas. The authors present a simple, working web platform (TicTrainer) that implements a strategy called reward-enhanced exposure and response prevention (RE-ERP). This strategy sacrifices most expert therapist components of ERP, focusing only on increasing the duration of time for which the user can suppress tics through automated differential reinforcement of tic-free periods (DRO). RE-ERP requires an external tic monitor, such as a parent, during training sessions. The user sees increasing digital rewards for longer and longer periods of successful tic suppression, similar to a video game score. TicTrainer is designed with security in mind, storing no personally identifiable health information, and has features to facilitate research, including optional masked comparison of tics during DRO vs. noncontingent reward conditions. A working instance of TicTrainer is available from https://tictrainer.com/.
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Affiliation(s)
- Jonathan K. Black
- Ira A. Fulton College of Engineering and Technology, Brigham Young University, Provo, UT, 84602, USA
| | - Kevin J. Black
- Washington University School of Medicine, St. Louis, MO, 63110, USA
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