Temporary deep brain stimulation in Gilles de la Tourette syndrome: A feasible approach?

Neurosurgical management of Tourette syndrome: A literature review and analysis of a case series treated with deep brain stimulation

Tourette syndrome (TS) is a heterogeneous disorder, which clinical presentation includes both multiple motor and vocal tics and commonly associated psychiatric conditions (obsessive-compulsive disorder, attention deficit hyperactivity disorder, depression, anxiety, etc.). Treatment options primarily consist of non-pharmacological interventions (habit reversal training, relaxation techniques, cognitive behavioral therapy, and social rehabilitation) and pharmacotherapy. In case of the intractable forms, neurosurgical treatment may be considered, primarily deep brain stimulation (DBS). DBS appear to be effective in medically intractable TS patients, although, the preferential brain target is still not defined. The majority of studies describe small number of cases and the issues of appropriate patient selection and ethics remain to be clarified. In this article, we review the main points in management of TS, discuss possible indications and contraindications for neurosurgical treatment, and analyze our experience of DBS in a case series of refractory TS patients with the focus on target selection and individual outcomes.

European clinical guidelines for Tourette syndrome and other tic disorders-version 2.0. Part IV: deep brain stimulation

In 2011 the European Society for the Study of Tourette Syndrome (ESSTS) published its first European clinical guidelines for the treatment of Tourette Syndrome (TS) with part IV on deep brain stimulation (DBS). Here, we present a revised version of these guidelines with updated recommendations based on the current literature covering the last decade as well as a survey among ESSTS experts. Currently, data from the International Tourette DBS Registry and Database, two meta-analyses, and eight randomized controlled trials (RCTs) are available. Interpretation of outcomes is limited by small sample sizes and short follow-up periods. Compared to open uncontrolled case studies, RCTs report less favorable outcomes with conflicting results. This could be related to several different aspects including methodological issues, but also substantial placebo effects. These guidelines, therefore, not only present currently available data from open and controlled studies, but also include expert knowledge. Although the overall database has increased in size since 2011, definite conclusions regarding the efficacy and tolerability of DBS in TS are still open to debate. Therefore, we continue to consider DBS for TS as an experimental treatment that should be used only in carefully selected, severely affected and otherwise treatment-resistant patients.

Tics and functional tic-like movements: Can we tell them apart?

Within the broad spectrum of movement disorders, tics and functional tic-like movements belong to a particular clinical category. Both types of movements are within the range of normal movement kinematics and muscle synergies, but appear repetitive and without appropriate context embedment. Historically, there have been many attempts to separate the 2 types of movements, but because of their phenomenological overlap, clinical distinction may be prone to error, and misdiagnoses may often occur. Most importantly, the 2 types of movement may coexist. Here, we review the available literature on the 2 types of motor phenomena and demonstrate some of the difficulties in distinguishing tics from functional tic-like movements on clinical grounds. We also highlight similarities and differences in pathophysiologic characteristics, documenting the significance of action monitoring, attentional allocation, and behavioral reinforcement in both types of movements, as well as in their risk factors. We discuss the overlap of current behavioral treatments for tics and functional tic-like movements and emphasize implications of diagnostic mislabeling. Such implications include the need to tailor behavioral treatment approaches to individual phenomenological profiles and guiding decision making for severe patients requiring invasive interventions, such as deep brain stimulation. A deeper insight from clinicians with respect to persisting challenges in classifying and differentiating these motor phenomena could accelerate the development of reliable clinical and physiologic markers (i.e., next generation phenotyping) and a neurobiology-driven therapeutic approach for these motor phenomena.

Deep brain stimulation for Gilles de la Tourette syndrome in children and youth: a meta-analysis with individual participant data

Objective

Gilles de la Tourette syndrome (GTS) is a disorder characterized by motor and vocal tics. Although by definition the onset of GTS is before age 18 years, clinical trials of deep brain stimulation (DBS) have been conducted only in adults. Using individual participant data (IPD) meta-analysis methodology, the current study investigated the safety and efficacy of DBS as a treatment for GTS in children and youth.

Methods

A systematic review with no date or language restrictions was performed according to the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) statement. Three electronic databases were searched: PubMed, EMBASE, and Web of Science. From 843 articles screened, the IPD of 58 children and youth (ages 12–21 years) extracted from 21 articles were collected and analyzed. A mixed-effects univariable analysis followed by multivariable hierarchical regression was performed using change in the Yale Global Tic Severity Scale (YGTSS) score as the primary outcome and reported measures of comorbidities as secondary outcomes.

Results

The authors’ results showed an average improvement of 57.5% ± 24.6% across studies on the YGTSS. They also found that comorbid depression and stimulation pulse width each correlated negatively with outcome (p < 0.05). In patients with less severe GTS, greater improvements were evident following thalamic stimulation. More than one-quarter (n = 16, 27.6%) of participants experienced side effects, the majority of which were minor.

Conclusions

DBS in the pediatric population may be an effective option with a moderate safety profile for treatment of GTS in carefully selected children and youth. Large, prospective studies with long-term follow-up are necessary to understand how DBS influences tic symptoms and may alter the natural course of GTS in children.

Deep brain stimulation in Tourette's syndrome: evidence to date

Tourette's syndrome (TS) is a neurodevelopmental disorder that comprises vocal and motor tics associated with a high frequency of psychiatric comorbidities, which has an important impact on quality of life. The onset is mainly in childhood and the symptoms can either fade away or require pharmacological therapies associated with cognitive-behavior therapies. In rare cases, patients experience severe and disabling symptoms refractory to conventional treatments. In these cases, deep brain stimulation (DBS) can be considered as an interesting and effective option for symptomatic control. DBS has been studied in numerous trials as a therapy for movement disorders, and currently positive data supports that DBS is partially effective in reducing the motor and non-motor symptoms of TS. The average response, mostly from case series and prospective cohorts and only a few controlled studies, is around 40% improvement on tic severity scales. The ventromedial thalamus has been the preferred target, but more recently the globus pallidus internus has also gained some notoriety. The mechanism by which DBS is effective on tics and other symptoms in TS is not yet understood. As refractory TS is not common, even reference centers have difficulties in performing large controlled trials. However, studies that reproduce the current results in larger and multicenter randomized controlled trials to improve our knowledge so as to support the best target and stimulation settings are still lacking. This article will discuss the selection of the candidates, DBS targets and mechanisms on TS, and clinical evidence to date reviewing current literature about the use of DBS in the treatment of TS.

Ethics of Deep Brain Stimulation in Adolescent Patients with Refractory Tourette Syndrome: a Systematic Review and Two Case Discussions

Introduction

Tourette Syndrome (TS) is a childhood onset disorder characterized by vocal and motor tics and often remits spontaneously during adolescence. For treatment refractory patients, Deep Brain Stimulation (DBS) may be considered.

Methods and Results

We discuss ethical problems encountered in two adolescent TS patients treated with DBS and systematically review the literature on the topic. Following surgery one patient experienced side effects without sufficient therapeutic effects and the stimulator was turned off. After a second series of behavioural treatment, he experienced a tic reduction of more than 50%. The second patient went through a period of behavioural disturbances that interfered with optimal programming, but eventually experienced a 70% tic reduction. Sixteen DBS surgeries in adolescent TS patients have been reported, none of which pays attention to ethical aspects.

Discussion

Specific ethical issues arise in adolescent TS patients undergoing DBS relating both to clinical practice as well as to research. Attention should be paid to selecting patients fairly, thorough examination and weighing of risks and benefits, protecting the health of children and adolescents receiving DBS, special issues concerning patient's autonomy, and the normative impact of quality of life. In research, registration of all TS cases in a central database covering a range of standardized information will facilitate further development of DBS for this indication.

Conclusion

Clinical practice should be accompanied by ongoing ethical reflection, preferably covering not only theoretical thought but providing also insights in the views and perspectives of those concerned, that is patients, family members and professionals.

Deep brain stimulation for psychiatric disorders: Is there an impact on social functioning?

BACKGROUND

Deep brain stimulation (DBS) for refractory psychiatric disorders shows promising effects on symptom-reduction, however, little is known regarding the effects of DBS on social outcome.

METHODS

A PubMed search based on original studies of DBS for psychiatric disorders [treatment resistant depression (TRD), Gilles de la Tourette's syndrome (GTS), and obsessive compulsive disorder (OCD)] was conducted. Data on social outcome following surgery were extracted and analyzed.

RESULTS

Social functioning was not a primary outcome measure in the reviewed article. The literature is incomplete and inconclusive on this variable, however from the reported data, there is some evidence that DBS has the potential to improve social functioning.

CONCLUSIONS

More systematic and detailed data gathering and reporting on social outcome with longer follow-ups are needed to evaluate more exhaustively the role of DBS in refractory psychiatric disorders.

The Use of Deep Brain Stimulation in Tourette Syndrome

Tourette syndrome (TS) is a childhood neurobehavioural disorder, characterised by the presence of motor and vocal tics, typically starting in childhood but persisting in around 20% of patients into adulthood. In those patients who do not respond to pharmacological or behavioural therapy, deep brain stimulation (DBS) may be a suitable option for potential symptom improvement. This manuscript attempts to summarise the outcomes of DBS at different targets, explore the possible mechanisms of action of DBS in TS, as well as the potential of adaptive DBS. There will also be a focus on the future challenges faced in designing optimized trials.

Deep Brain Stimulation in Gilles de la Tourette Syndrome: What Does the Future Hold? A Cohort of 48 Patients

BACKGROUND

Gilles de la Tourette syndrome (GTS) is a severe neuropsychiatric disorder with childhood onset, characterized by disabling motor and vocal tics lasting for more than 1 year and associated with a wide range of psychiatric comorbidities. Pharmacological treatment is indicated for moderate to severe GTS patients. However, when GTS is refractory to conventional medical and behavioral treatments, deep brain stimulation (DBS) can be considered as a last resort therapeutic avenue.

OBJECTIVE

To evaluate the efficacy of DBS and its comorbidities in the largest pool of GTS patients to date.

METHODS

Our cohort study was based on 48 patients' refractory to conventional treatment who underwent DBS for GTS at Galeazzi Institute, Milan, Italy. An exhaustive preoperative and a follow-up battery of tests was performed including the Yale Global Tic Severity Rating Scale, the Yale-Brown Obsessive Compulsive Scale, the Beck Depression Inventory, the State Trait Anxiety Inventory, and the Subjective Social Impairment on a 10-point Visual Analogue Scale tests.

RESULTS

Eleven patients in whom the device was removed for inflammatory complications or for poor compliance were excluded from final analysis. Twenty-seven of the remaining 37 patients had a Yale Global Tic Severity Rating Scale score at the last follow-up that was less than 35. Of the 37 patients, in 29 cases (78%) a reduction of more than 50% of the Yale Global Tic Severity Rating Scale score was observed.

CONCLUSION

The clinical efficacy of DBS in GTS is promising. Although DBS is associated with risks, as is any surgical intervention, DBS should be considered as a last resort therapeutic option in carefully selected GTS patients.

Tourette syndrome research highlights 2015

We present selected highlights from research that appeared during 2015 on Tourette syndrome and other tic disorders. Topics include phenomenology, comorbidities, developmental course, genetics, animal models, neuroimaging, electrophysiology, pharmacology, and treatment. We briefly summarize articles whose results we believe may lead to new treatments, additional research or modifications in current models of TS.