Deep brain stimulation in Tourette syndrome: the known and the unknown

Efficacy of deep brain stimulation for Tourette syndrome and its comorbidities: A meta-analysis

Tourette Syndrome (TS) is a neurodevelopmental disorder characterized by multiple motor and vocal tics, often accompanied by comorbid disorders. Optional treatments for patients with TS include behavioral therapy, pharmacotherapy, and neurostimulation techniques. Deep brain stimulation (DBS) has been considered a therapeutic approach for refractory TS and its comorbid symptoms. However, systematic comparison is necessary to understand the therapeutic effect of DBS among patients with TS with various comorbid symptoms, demographic characteristics, or stimulation targets. Consequently, our research aimed to assess the clinical efficacy of DBS in alleviating the symptoms of TS and its comorbidities. A systematic literature search was conducted across five databases: PubMed, Web of Science, MEDLINE, Embase, and PsycINFO. The primary outcome was the mean change in the global score of the Yale Global Tic Severity Scale (YGTSS), which assesses the severity of tics. The secondary outcomes included mean improvement of comorbid symptoms, such as obsessive-compulsive behaviors (OCB), depression symptoms and anxiety symptoms. In total, 51 studies with 673 participants were included in this meta-analysis. Overall, the DBS led to a significant improvement in tic symptoms (p ​< ​0.001), as well as the comorbid obsessive-compulsive, depression, and anxiety symptoms with effect sizes of 1.88, 0.88, 1.04, and 0.76 accordingly. In the subgroup analysis, we found that striatum stimulation led to a more significant improvement in OCB in patients with TS compared to that observed with thalamic stimulation (p ​= ​0.017). The relationship between sex, age, and target with the improvement of tics, depression, and anxiety was not statistically significant (p ​= ​0.923, 0.438, 0.591 for different male proportions; p ​= ​0.463, 0.425, 0.105 for different age groups; p ​= ​0.619, 0.113, 0.053 for different targets). In conclusion, DBS is an efficient treatment option for TS, as well as the comorbid OCB, depression symptoms, and anxiety symptoms. It is important to highlight that stimulating the striatum is more effective in managing obsessive-compulsive symptoms compared to stimulating the thalamus.

Electrocardiographic approach strategies in patients with Parkinson disease treated with deep brain stimulation

Deep brain stimulation (DBS) is an interdisciplinary and reversible therapy that uses high-frequency electrical stimulation to correct aberrant neural pathways in motor and cognitive neurological disorders. However, the high frequency of the waves used in DBS can interfere with electrical recording devices (e.g., electrocardiogram, electroencephalogram, cardiac monitor), creating artifacts that hinder their interpretation. The compatibility of DBS with these devices varies and depends on factors such as the underlying disease and the configuration of the neurostimulator. In emergencies where obtaining an electrocardiogram is crucial, the need for more consensus on reducing electrical artifacts in patients with DBS becomes a significant challenge. Various strategies have been proposed to attenuate the artifact generated by DBS, such as changing the DBS configuration from monopolar to bipolar, temporarily deactivating DBS during electrocardiographic recording, applying frequency filters both lower and higher than those used by DBS, and using non-standard leads. However, the inexperience of medical personnel, variability in DBS models, or the lack of a controller at the time of approach limit the application of these strategies. Current evidence on their reproducibility and efficacy is limited. Due to the growing elderly population and the rising utilization of DBS, it is imperative to create electrocardiographic methods that are easily accessible and reproducible for general physicians and emergency services.

Subthalamic deep brain stimulation for refractory Gilles de la Tourette's syndrome: clinical outcome and functional connectivity

BACKGROUND

Deep brain stimulation (DBS) is a promising novel approach for managing refractory Gilles de la Tourette's syndrome (GTS). The subthalamic nucleus (STN) is the most common DBS target for treating movement disorders, and smaller case studies have reported the efficacy of bilateral STN-DBS treatment for relieving tic symptoms. However, management of GTS and treatment mechanism of STN-DBS in GTS remain to be elucidated.

METHODS

Ten patients undergoing STN-DBS were included. Tics severity was evaluated using the Yale Global Tic Severity Scale. The severities of comorbid psychiatric symptoms of obsessive-compulsive behavior (OCB), attention-deficit/hyperactivity disorder, anxiety, and depression; social and occupational functioning; and quality of life were assessed. Volumes of tissue activated were used as seed points for functional connectivity analysis performed using a control dataset.

RESULTS

The overall tics severity significantly reduced, with 62.9% ± 26.2% and 58.8% ± 27.2% improvements at the 6- and 12-months follow-up, respectively. All three patients with comorbid OCB showed improvement in their OCB symptoms at both the follow-ups. STN-DBS treatment was reasonably well tolerated by the patients with GTS. The most commonly reported side effect was light dysarthria. The stimulation effect of STN-DBS might regulate these symptoms through functional connectivity with the thalamus, pallidum, substantia nigra pars reticulata, putamen, insula, and anterior cingulate cortices.

CONCLUSIONS

STN-DBS was associated with symptomatic improvement in severe and refractory GTS without significant adverse events. The STN is a promising DBS target by stimulating both sensorimotor and limbic subregions, and specific brain area doses affect treatment 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.

Recent progress on Tourette syndrome

Tic disorders and Tourette syndrome are the most common movement disorders in children and are characterized by movements or vocalizations. Clinically, Tourette syndrome is frequently associated with comorbid psychiatric symptoms. Although dysfunction of cortical–striatal–thalamic–cortical circuits with aberrant neurotransmitter function has been considered the proximate cause of tics, the mechanism underlying this association is unclear. Recently, many studies have been conducted to elucidate the epidemiology, clinical course, comorbid symptoms, and pathophysiology of tic disorders by using laboratory studies, neuroimaging, electrophysiological testing, environmental exposure, and genetic testing. In addition, many researchers have focused on treatment for tics, including behavioral therapy, pharmacological treatment, and surgical treatment. Here, we provide an overview of recent progress on Tourette syndrome.

Thalamic deep brain stimulation for Tourette Syndrome: A naturalistic trial with brief randomized, double-blinded sham-controlled periods

BACKGROUND

There is still a lack of controlled studies to prove efficacy of thalamic deep brain stimulation for Tourette's Syndrome.

OBJECTIVES

In this controlled trial, we investigated the course of tic severity, comorbidities and quality of life during thalamic stimulation and whether changes in tic severity can be assigned to ongoing compared to sham stimulation.

METHODS

We included eight adult patients with medically refractory Tourette's syndrome. Bilateral electrodes were implanted in the centromedian-parafascicular-complex and the nucleus ventro-oralis internus. Tic severity, quality of life and comorbidities were assessed before surgery as well as six and twelve months after. Short randomized, double-blinded sham-controlled crossover sequences with either active or sham stimulation were implemented at both six- and twelve-months' assessments. The primary outcome measurement was the difference in the Yale Global Tic Severity Scale tic score between active and sham stimulation. Adverse events were systematically surveyed for all patients to evaluate safety.

RESULTS

Active stimulation resulted in significantly higher tic reductions than sham stimulation (F = 79.5; p = 0.001). Overall quality of life and comorbidities improved significantly in the open-label-phase. Over the course of the trial two severe adverse events occurred that were resolved without sequelae.

CONCLUSION

Our results provide evidence that thalamic stimulation is effective in improving tic severity and overall quality of life. Crucially, the reduction of tic severity was primarily driven by active stimulation. Further research may focus on improving stimulation protocols and refining patient selection to improve efficacy and safety of deep brain stimulation for Tourette's Syndrome.

Deep Brain Stimulation for Obsessive-Compulsive Disorder: Real World Experience Post-FDA-Humanitarian Use Device Approval

Background: While case series have established the efficacy of deep brain stimulation (DBS) in treating obsessive-compulsive disorder (OCD), it has been our experience that few OCD patients present without comorbidities that affect outcomes associated with DBS treatment. Here we present our experience with DBS therapy for OCD in patients who all have comorbid disease, together with the results of our programming strategies. Methods: For this case series, we assessed five patients who underwent ventral capsule/ventral striatum (VC/VS) DBS for OCD between 2015 and 2019 at the University of Colorado Hospital. Every patient in this cohort exhibited comorbidities, including substance use disorders, eating disorder, tic disorder, and autism spectrum disorder. We conducted an IRB-approved, retrospective study of programming modifications and treatment response over the course of DBS therapy. Results: In addition to patients' subjective reports of improvement, we observed significant improvement in the Yale-Brown Obsessive-Compulsive Scale (44%), the Montgomery-Asberg Depression Rating Scale (53%), the Quality of Life Enjoyment and Satisfaction Questionnaire (27%), and the Hamilton Anxiety Rating scales (34.9%) following DBS. With respect to co-morbid disease, there was a significant improvement in a patient with tic disorder's Total Tic Severity Score (TTSS) (p = 0.005). Conclusions: DBS remains an efficacious tool for the treatment of OCD, even in patients with significant comorbidities in whom DBS has not previously been investigated. Efficacious treatment results not only from the accurate placement of the electrodes by the surgeon but also from programming by the psychiatrist.

Sustained Relief after Pallidal Stimulation Interruption in Tourette's Syndrome Treated with Simultaneous Capsulotomy

INTRODUCTION

Globus pallidus internus (GPi) deep brain stimulation (DBS) combined with anterior capsulotomy offers a promising treatment option for severe medication-refractory cases of Tourette's syndrome (TS) with psychiatric comorbidities. Several patients treated with this combined surgery experienced sustained relief after discontinuation of stimulation over the course of treatment.

METHODS

Retrospectively, the medical records and clinical outcomes were reviewed of 8 patients (6 men; 2 women with mean age of 20.3 years) who had undergone bilateral GPi-DBS combined with anterior capsulotomy for medically intractable TS and psychiatric comorbidities. All patients had experienced an accidental interruption or intentional withdrawal of pallidal stimulation during treatment.

RESULTS

The widespread clinical benefits achieved during the combined treatment were fully maintained after intentional or accidental DBS discontinuation. The improvement in overall tic symptoms achieved was on average 78% at the follow-up or close to the DBS discontinuation, while it was 83% at last follow-up (LFU). At LFU, most patients had functionally recovered; exhibited only mild tics; displayed minor or no obsessive-compulsive disorder symptoms, anxiety, or depression; and experienced a much better quality of life.

CONCLUSION

Bilateral GPi-DBS combined with anterior capsulotomy appears to result in marked and sustained improvements in TS symptoms and psychiatric comorbidities, which are fully maintained over time, even without pallidal stimulation.

Paediatric deep brain stimulation: ethical considerations in malignant Tourette syndrome

Gilles de la Tourette syndrome (TS) is a childhood neuropsychiatric disorder characterised by the presence of motor and vocal tics. Patients with malignant TS experience severe disease sequelae; risking morbidity and mortality due to tics, self-harm, psychiatric comorbidities and suicide. By definition, those cases termed 'malignant' are refractory to all conventional psychiatric and pharmacological regimens. In these instances, deep brain stimulation (DBS) may be efficacious. Current 2015 guidelines recommend a 6-month period absent of suicidal ideation before DBS is offered to patients with TS. We therefore wondered whether it may be ethically justifiable to offer DBS to a minor with malignant TS. We begin with a discussion of non-maleficence and beneficence. New evidence suggests that suicide risk in young patients with TS has been underestimated. In turn, DBS may represent an invaluable opportunity for children with malignant TS to secure future safety, independence and fulfilment. Postponing treatment is associated with additional risks. Ultimately, we assert this unique risk-benefit calculus justifies offering DBS to paediatric patients with malignant TS. A multidisciplinary team of clinicians must determine whether DBS is in the best interest of their individual patients. We conclude with a suggestion for future TS-DBS guidelines regarding suicidal ideation. The importance of informed consent and assent is underscored.

Tourette's disorder in children and adolescents

Tourette's disorder (TD) is one of the five American Psychiatric Association's 2013 Diagnostic and Statistical Manual of Mental Disorders (DSM-5) classifications of tic disorders. Eponymously linked with the noted 19th century French physician, Gilles de la Tourette [1857-1904], this disorder is identified in 0.3% to 0.7% of the population. It is characterized as a familial neuropsychiatric condition with multiple motor tics and vocal tics (one or more) present for more than 1 year with varying severity. The underlying pathophysiology involves dysfunctional activity of the basal ganglia and circuitry of the frontal cortex as well as dorsolateral striatum deficits. Contributory factors include genetic features interacting with milieu influences. A number of comorbid disorders are seen including obsessive-compulsive disorder (OCD) and attention-deficit/hyperactivity disorder (ADHD). Concepts of management are considered including behavioral therapy and pharmacologic approaches with alpha-adrenoceptor agonists, atypical antipsychotics (AAs), haloperidol, pimozide and others. Other management includes botulinum injections and deep brain stimulation in adults.