Transcranial magnetic stimulation for treatment of Tourette syndrome

Singh S, Kumar S, Kumar N, Verma R. Low-frequency Repetitive Transcranial Magnetic Stimulation for Treatment of Tourette Syndrome: A Naturalistic Study with 3 Months of Follow-up. Indian J Psychol Med. 2018 Sep-Oct;40(5):482-486.

Abstract

The objective of this study is to report the effects of low-frequency repetitive transcranial magnetic stimulation (rTMS) in three patients with medication-refractory Tourette syndrome (TS) and over 3-month follow-up. A review of literature on the use of rTMS for the treatment of TS is also presented. Three patients with severe, medication-refractory TS and comorbid obsessive-compulsive disorder (OCD) in two of them, received an open-label trial of rTMS at 1 Hz frequency for 4-week duration. The first two cases of TS-OCD showed, on average, around 57% improvement in Yale Global Tic Severity Scale (YGTSS) scores (65% and 50%) and 45% improvement in Yale-Brown Obsessive-compulsive Scale (Y-BOCS) scores; however, the third case of pure-TS showed marginal improvement of 10% only. The improvement in TS-OCD patients with rTMS treatment was maintained at the end of 3-month follow-up, with an average reduction of about 49% (58% and 40%) and 36% observed in YGTSS and Y-BOCS scores, respectively. The present study supports the use of low-frequency rTMS to improve tics and OCD symptoms in patients with severe, medication-refractory TS-OCD. Further, the beneficial effects of rTMS treatment were maintained substantially over 3-month follow-up period.

Behler N, Leitner B, Mezger E, Weidinger E, Musil R, Blum B, Kirsch B, Wulf L, Löhrs L, Winter C, Padberg F, Palm U. Cathodal tDCS Over Motor Cortex Does Not Improve Tourette Syndrome: Lessons Learned From a Case Series. Front Behav Neurosci. 2018 Aug 24;12:194.

Abstract

Introduction: Current pathophysiological hypotheses of Gilles de la Tourette Syndrome (GTS) refer to temporally abnormal neuronal activation in cortico-striato-thalamo-cortical (CSTC) networks. Modifying cortical activity by non-invasive brain-stimulation appears to be a new treatment option in GTS. Background: Previous studies suggested therapeutic effects of cathodal transcranial direct current stimulation (tDCS) to pre-supplementary motor areas (SMA), however, treatment modalities concerning electrode placement, current intensity and stimulation-rate have not been systematically explored. Aim of this study was to assess efficacy of an alternative stimulation regime on GTS symptoms in a pilot study. To test a treatment protocol with tDCS twice a day, we administered 10 sessions over 5 days of bilateral cathodal tDCS (30 min, 2 mA) over the pre-SMA in three patients with severe GTS. Tic severity as well as obsessive-compulsive (OC) symptoms and affective scales were rated before and after tDCS treatment. Discussion: Only one out of three patients showed a 34.5% reduction in tic severity. The two other patients showed an increase in tic severity. All patients showed a mild increase in positive affect and a reduction in negative affect, OC symptom changes were heterogeneous. Our results do not support earlier findings of extensive therapeutic effects of cathodal tDCS on tics in patients with GTS and show that prediction of stimulation effects on a targeted brain area remains inaccurate. Concluding Remarks: Future research will have to focus on the determination of most effective stimulation modes regarding site, polarity and frequency of tDCS in GTS patients.

Grados M, Huselid R, Duque-Serrano L. Transcranial Magnetic Stimulation in Tourette Syndrome: A Historical Perspective, Its Current Use and the Influence of Comorbidities in Treatment Response. Brain Sci. 2018 Jul 6;8(7).

Abstract

BACKGROUND:

Tourette syndrome (TS) is a childhood-onset neuropsychiatric disorder consisting of impairing motor and vocal tics which often persists adolescent and adult years. In this older refractory group, standard treatments such as pharmacotherapy and psychotherapeutic interventions may only have limited effects. Based on electrical cortical dysregulation in individuals with TS, a novel approach has employed brain stimulation strategies to modulate the putative aberrant neural electrical activity in pathways that may underlie tics, such as insula-supplementary motor area (SMA) connectivity.

METHODS:

This review will examine all published clinical trials employing transcranial magnetic stimulation (TMS) to ameliorate tics, and discuss a framework for the pathophysiology of TS in relation to electrical brain activity. A framework for future research in tic disorders using TMS and imaging targeting neuroplasticity will be discussed.

RESULTS:

Therapeutic electrical brain activity modulation with TMS has been carried out in stroke neuro-rehabilitation and neuropsychiatry, including trials in TS. Eleven trials document the use of TMS in TS targeting several brain areas, a positive effect is seen for those trials targeting the SMA. In particular, it appears that younger individuals with concurrent attention-deficit hyperactivity disorder (ADHD) benefit the most.

CONCLUSIONS:

TMS can be used as an effective tool to explore the psychophysiology of TS and potentially provide a therapeutic option. Ultimately, translational research using TMS in TS needs to explore connectivity differences pre- and post-treatment in individuals with TS that are linked to improvement in tic symptoms, with an emphasis on approaches using functional neuroimaging as well as other probes of neuroplasticity.

Hsu CW, Wang LJ, Lin PY. Efficacy of repetitive transcranial magnetic stimulation for Tourette syndrome: A systematic review and meta-analysis. Brain Stimul. 2018 Sep - Oct;11(5):1110-1118.

Abstract

BACKGROUND:

While previous studies have investigated the effect of repetitive transcranial magnetic stimulation (rTMS) in treating Tourette syndrome (TS), the results remain inconclusive.

OBJECTIVE:

We aim to systematically review the existing literature related to the efficacy of rTMS in TS and synthesize the results through meta-analysis.

METHODS:

We searched for PubMed, Embase, Cochrane Library, and ClinicalTrials.gov databases without language restriction through January 1, 2018, and included randomized-controlled and open-label trials that assessed the treatment effect of rTMS for tic symptoms. We used a random-effects model to pool effect sizes, which were expressed as Hedges' g and 95% confidence intervals (CIs). The outcomes include symptom improvement of tic, obsessive-compulsive (OC), and attention-deficit hyperactivity disorder. Distribution of sex, age, and differences of rTMS protocol were examined as potential moderators.

RESULTS:

Eight studies were included in the meta-analysis. rTMS significantly improved tic (g = -0.61; CI: -0.94 to -0.29) and OC (g = -0.48; CI: -0.83 to -0.14) symptoms in TS patients, compared to baseline. However, active rTMS was not effective in tic or OC symptoms among patients with TS when controlled for placebo. Furthermore, stimulation of the bilateral supplementary motor areas was more effective in tic symptoms than that of other areas (g = -0.70; CI: -1.11 to -0.30 vs. g = -0.36; CI: -0.84 to 0.14). Moreover, a younger age was associated with a better treatment effect (coefficient = 0.03, p = 0.027).

CONCLUSION:

Current study indicates that rTMS has a significant effect on tic and OC symptoms in TS patients.