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Kahl CK, Swansburg R, Kirton A, Pringsheim T, Wilcox G, Zewdie E, Harris A, Croarkin PE, Nettel-Aguirre A, Chenji S, MacMaster FP. Targeted Interventions in Tourette's using Advanced Neuroimaging and Stimulation (TITANS): study protocol for a double-blind, randomised controlled trial of transcranial magnetic stimulation (TMS) to the supplementary motor area in children with Tourette's syndrome. BMJ Open 2021; 11:e053156. [PMID: 34952879 PMCID: PMC8712978 DOI: 10.1136/bmjopen-2021-053156] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/03/2022] Open
Abstract
INTRODUCTION Tourette's syndrome (TS) affects approximately 1% of children. This study will determine the efficacy and safety of paired comprehensive behavioural intervention for tics (CBIT) plus repetitive transcranial magnetic stimulation (rTMS) treatment in children with Tourette's syndrome. We hypothesise that CBIT and active rTMS to the supplementary motor area (SMA) will (1) decrease tic severity, and (2) be associated with changes indicative of enhanced neuroplasticity (eg, changes in in vivo metabolite concentrations and TMS neurophysiology measures). METHODS AND ANALYSIS This study will recruit 50 youth with TS, aged 6-18 for a phase II, double-blind, block randomised, sham-controlled trial comparing active rTMS plus CBIT to sham rTMS plus CBIT in a 1:1 ratio. The CBIT protocol is eight sessions over 10 weeks, once a week for 6 weeks and then biweekly. The rTMS protocol is 20 sessions of functional MRI-guided, low-frequency (1 Hz) rTMS targeted to the bilateral SMA over 5 weeks (weeks 2-6). MRI, clinical and motor assessments and neurophysiological evaluations including motor mapping will be performed 1 week before CBIT start, 1 week after rTMS treatment and 1 week after CBIT completion. The primary outcome measure is Tourette's symptom change from baseline to post-CBIT treatment, as measured by the Yale Global Tic Severity Scale. Secondary outcomes include changes in imaging, neurophysiological and behavioural markers. ETHICS AND DISSEMINATION Ethical approval by the Conjoint Health Research Ethics Board (REB18-0220). The results of this study will be published in peer-reviewed scientific journals, on ClinicalTrials.gov and shared with the Tourette and OCD Alberta Network. The results will also be disseminated through the Alberta Addictions and Mental Health Research Hub. TRIAL REGISTRATION NCT03844919.
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Affiliation(s)
- Cynthia K Kahl
- Department of Psychiatry, University of Calgary, Calgary, Alberta, Canada
- Department of Pediatrics, University of Calgary, Calgary, Alberta, Canada
| | - Rose Swansburg
- Department of Psychiatry, University of Calgary, Calgary, Alberta, Canada
- Department of Pediatrics, University of Calgary, Calgary, Alberta, Canada
| | - Adam Kirton
- Department of Pediatrics, University of Calgary, Calgary, Alberta, Canada
- Department of Clinical Neurosciences, University of Calgary, Calgary, Alberta, Canada
| | - Tamara Pringsheim
- Department of Psychiatry, University of Calgary, Calgary, Alberta, Canada
- Department of Pediatrics, University of Calgary, Calgary, Alberta, Canada
- Department of Clinical Neurosciences, University of Calgary, Calgary, Alberta, Canada
- Community Health Sciences, University of Calgary Cumming School of Medicine, Calgary, Alberta, Canada
| | - Gabrielle Wilcox
- School and Applied Child Psychology, Werklund School of Education, University of Calgary, Calgary, Alberta, Canada
| | - Ephrem Zewdie
- Department of Pediatrics, University of Calgary, Calgary, Alberta, Canada
- Department of Clinical Neurosciences, University of Calgary, Calgary, Alberta, Canada
| | - Ashley Harris
- Department of Pediatrics, University of Calgary, Calgary, Alberta, Canada
- Department of Radiology, University of Calgary, Calgary, Alberta, Canada
| | - Paul E Croarkin
- Psychiatry and Psychology, Mayo Clinic College of Medicine, Rochester, Minnesota, USA
| | - Alberto Nettel-Aguirre
- Department of Pediatrics, University of Calgary, Calgary, Alberta, Canada
- Community Health Sciences, University of Calgary Cumming School of Medicine, Calgary, Alberta, Canada
| | - Sneha Chenji
- Department of Psychiatry, University of Calgary, Calgary, Alberta, Canada
- Department of Pediatrics, University of Calgary, Calgary, Alberta, Canada
| | - Frank P MacMaster
- Department of Psychiatry, University of Calgary, Calgary, Alberta, Canada
- Department of Pediatrics, University of Calgary, Calgary, Alberta, Canada
- Provincial Addictions and Mental Health, Alberta Health Services, Calgary, Alberta, Canada
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Abstract
Background:Tics, defined as quick, rapid, sudden, recurrent, non-rhythmic motor movements or vocalizations are required components of Tourette Syndrome (TS) - a complex disorder characterized by the presence of fluctuating, chronic motor and vocal tics, and the presence of co-existing neuropsychological problems. Despite many advances, the underlying pathophysiology of tics/TS remains unknown.Objective:To address a variety of controversies surrounding the pathophysiology of TS. More specifically: 1) the configuration of circuits likely involved; 2) the role of inhibitory influences on motor control; 3) the classification of tics as either goal-directed or habitual behaviors; 4) the potential anatomical site of origin, e.g. cortex, striatum, thalamus, cerebellum, or other(s); and 5) the role of specific neurotransmitters (dopamine, glutamate, GABA, and others) as possible mechanisms (Abstract figure).Methods:Existing evidence from current clinical, basic science, and animal model studies are reviewed to provide: 1) an expanded understanding of individual components and the complex integration of the Cortico-Basal Ganglia-Thalamo-Cortical (CBGTC) circuit - the pathway involved with motor control; and 2) scientific data directly addressing each of the aforementioned controversies regarding pathways, inhibition, classification, anatomy, and neurotransmitters.Conclusion:Until a definitive pathophysiological mechanism is identified, one functional approach is to consider that a disruption anywhere within CBGTC circuitry, or a brain region inputting to the motor circuit, can lead to an aberrant message arriving at the primary motor cortex and enabling a tic. Pharmacologic modulation may be therapeutically beneficial, even though it might not be directed toward the primary abnormality.
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Affiliation(s)
- Harvey S. Singer
- Department of Neurology, Johns Hopkins Hospital, Baltimore, MD, United States
| | - Farhan Augustine
- Department of Neurology, Johns Hopkins Hospital, Baltimore, MD, United States
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Abstract
Tics are sudden, rapid, recurrent, nonrhythmic motor movements or vocalizations (phonic productions) that are commonly present in children and are required symptoms for the diagnosis of Tourette syndrome. Despite their frequency, the underlying pathophysiology of tics/Tourette syndrome remains unknown. In this review, we discuss a variety of controversies surrounding the pathophysiology of tics, including the following: Are tics voluntary or involuntary? What is the role of the premonitory urge? Are tics due to excess excitatory or deficient inhibition? Is it time to adopt the contemporary version of the cortico-basal ganglia-thalamocortical (CBGTC) circuit? and Do we know the primary abnormal neurotransmitter in Tourette syndrome? Data from convergent clinical and animal model studies support complex interactions among the various CBGTC sites and neurotransmitters. Advances are being made; however, numerous pathophysiologic questions persist.
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Affiliation(s)
- Harvey S Singer
- Department of Neurology, Johns Hopkins Hospital, Baltimore, MD, USA
| | - Farhan Augustine
- Department of Neurology, Johns Hopkins Hospital, Baltimore, MD, USA
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Comparing GABA-dependent physiological measures of inhibition with proton magnetic resonance spectroscopy measurement of GABA using ultra-high-field MRI. Neuroimage 2017; 152:360-370. [PMID: 28284797 PMCID: PMC5440178 DOI: 10.1016/j.neuroimage.2017.03.011] [Citation(s) in RCA: 77] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2016] [Revised: 03/04/2017] [Accepted: 03/06/2017] [Indexed: 12/16/2022] Open
Abstract
Imbalances in glutamatergic (excitatory) and GABA (inhibitory) signalling within key brain networks are thought to underlie many brain and mental health disorders, and for this reason there is considerable interest in investigating how individual variability in localised concentrations of these molecules relate to brain disorders. Magnetic resonance spectroscopy (MRS) provides a reliable means of measuring, in vivo, concentrations of neurometabolites such as GABA, glutamate and glutamine that can be correlated with brain function and dysfunction. However, an issue of much debate is whether the GABA observed and measured using MRS represents the entire pool of GABA available for measurement (i.e., metabolic, intracellular, and extracellular) or is instead limited to only some portion of it. GABA function can also be investigated indirectly in humans through the use of non-invasive transcranial magnetic stimulation (TMS) techniques that can be used to measure cortical excitability and GABA-mediated physiological inhibition. To investigate this issue further we collected in a single session both types of measurement, i.e., TMS measures of cortical excitability and physiological inhibition and ultra-high-field (7 T) MRS measures of GABA, glutamate and glutamine, from the left sensorimotor cortex of the same group of right-handed individuals. We found that TMS and MRS measures were largely uncorrelated with one another, save for the plateau of the TMS IO curve that was negatively correlated with MRS-Glutamate (Glu) and intra-cortical facilitation (10ms ISI) that was positively associated with MRS-Glutamate concentration. These findings are consistent with the view that the GABA concentrations measured using the MRS largely represent pools of GABA that are linked to tonic rather than phasic inhibition and thus contribute to the inhibitory tone of a brain area rather than GABAergic synaptic transmission.
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