Efficacy and Safety of Deep Brain Stimulation in Tourette Syndrome: The International Tourette Syndrome Deep Brain Stimulation Public Database and Registry

Functional Neuroanatomy of Tics: A Brain Network Perspective

Tourette syndrome is defined by motor and vocal tics, yet our understanding of the pathophysiology of tics remains limited. Functional MRI (fMRI) can localize brain function related to the clinical phenomenology of tics. Here, we review extant fMRI studies examining brain activity during the premonitory urge, tic release, and tic suppression. Results are placed in the context of large-scale functional networks, given recent advancements in understanding the brain's functional network organization. During tic-related phenomena, brain activity follows consistent patterns involving specific networks, largely centered around the cingulo-opercular action mode network. This network-level framework provides a novel avenue for targeted-treatment methods.

Pain in Tourette Syndrome: A Comprehensive Review

Objectives: Recent survey data suggest that a high proportion of patients with Tourette syndrome (TS) experience pain, yet pain features in TS have not been previously investigated in a systematic manner. This article reviews the current understanding and impact of pain in TS as well as identifies possible areas for emphasis for future research on pain in TS. Methods: Using a comprehensive search strategy in two relevant research databases (PubMed and Scopus), we searched for relevant peer-reviewed, primary research articles, and review articles. Search terms used were Tourette syndrome, tic disorder, pain, pain management, sensory, and sensory gating. Results: A total of 116 pertinent articles were identified. Pain is reported by 47%-60% of individuals with TS and may relate to different aspects of tic phenomenology or other causes. Pain is more prevalent among TS patients than in the general population and negatively impacts quality of life. To standardize future research efforts, we propose the following classification: tic-related immediate pain, tic-related delayed injury/pain, suppression-related pain, premonitory urge-related pain, and associated primary pain syndromes. Altered sensory gating and interoceptive processing abnormalities are possible mechanisms contributing to pain in TS but warrant further study. Despite pain prevalence, most TS clinical rating scales and outcome measures used in therapeutic studies do not incorporate sufficient information regarding pain. Therapies known to improve pain in non-TS conditions that are also reported to improve tics have not been investigated for their effects on pain among TS patients. Conclusion: TS can be associated with a chronic pain syndrome that negatively affects quality of life. Future research using a systematic framework is needed to better understand pain cause(s) and prevalence, develop appropriate assessment methods, establish outcome measures, and understand mechanisms of pain in TS. Such investigations are likely to lead to therapeutic options for this troublesome symptom.

Cost-effectiveness analysis of deep brain stimulation for the treatment of alcohol use disorder and alcoholic liver disease

BACKGROUND

Alcohol use disorder (AUD) is a major public health concern and cause of mortality and morbidity. Alcohol-associated liver disease (ALD) is a debilitating complication of AUD, mitigated by abstinence from alcohol use. Deep brain stimulation (DBS) is emerging as a potential treatment for AUD. However, its cost-effectiveness compared to the standard medical treatment is unclear.

OBJECTIVE

To estimate the cost-effectiveness of DBS compared to medical management for patients with AUD and ALD.

METHODS

We utilized a decision analytic model based on published literature to conduct a cost-effectiveness analysis of costs and health outcomes for DBS and medical management in patients with AUD and ALD. We also carried out a threshold analysis to determine the probability of success necessary for DBS to be cost-effective. Costs were measured in 2024 US dollars and effectiveness in quality-adjusted life years (QALYs). We used a time horizon of 1-2 years and adopted a societal perspective.

RESULTS

Our results show that for AUD patients in general, DBS is not cost-effective at any DBS success rate. However, for advanced ALD patients, defined as fibrosis stage 3 or beyond DBS becomes cost-effective. For these patients, DBS is cost-effective over a two-year period at a $100,000 willingness-to-pay threshold at DBS success rates greater than 53 %. For advanced decompensated ALD patients, DBS is cost-effective over a one-year period at DBS success rate greater than 35 %.

CONCLUSION

Should it prove efficacious, DBS may be cost-effective for patients with AUD and ALD. Thus, future randomized controlled trials to evaluate its efficacy are warranted.

Neuroprotective Efficacy and Complementary Treatment with Medicinal Herbs: A Comprehensive Review of Recent Therapeutic Approaches in Epilepsy Management

Central Nervous System (CNS) disorders affect millions of people worldwide, with a significant proportion experiencing drug-resistant forms where conventional medications fail to provide adequate seizure control. This abstract delves into recent advancements and innovative therapies aimed at addressing the complex challenge of CNS-related drug-resistant epilepsy (DRE) management. The idea of precision medicine has opened up new avenues for epilepsy treatment. Herbs such as curcumin, ginkgo biloba, panax ginseng, bacopa monnieri, ashwagandha, and rhodiola rosea influence the BDNF pathway through various mechanisms. These include the activation of CREB, inhibition of NF-κB, modulation of neurotransmitters, reduction of oxidative stress, and anti- inflammatory effects. By promoting BDNF expression and activity, these herbs support neuroplasticity, cognitive function, and overall neuronal health. Novel antiepileptic drugs (AEDs) with distinct mechanisms of action demonstrate efficacy in refractory cases where traditional medications falter. Additionally, repurposing existing drugs for antiepileptic purposes presents a cost-effective strategy to broaden therapeutic choices. Cannabidiol (CBD), derived from cannabis herbs, has garnered attention for its anticonvulsant properties, offering a potential adjunctive therapy for refractory seizures. In conclusion, recent advances and innovative therapies represent a multifaceted approach to managing drug-resistant epilepsy. Leveraging precision medicine, neurostimulation technologies, novel pharmaceuticals, and complementary therapies, clinicians can optimize treatment outcomes and improve the life expectancy of patients living with refractory seizures. Genetic testing and biomarker identification now allow for personalized therapeutic approaches tailored to individual patient profiles. Utilizing next-generation sequencing techniques, researchers have elucidated genetic mutations.

Challenges and opportunities of acquiring cortical recordings for chronic adaptive deep brain stimulation

Deep brain stimulation (DBS), a proven treatment for movement disorders, also holds promise for the treatment of psychiatric and cognitive conditions. However, for DBS to be clinically effective, it may require DBS technology that can alter or trigger stimulation in response to changes in biomarkers sensed from the patient's brain. A growing body of evidence suggests that such adaptive DBS is feasible, it might achieve clinical effects that are not possible with standard continuous DBS and that some of the best biomarkers are signals from the cerebral cortex. Yet capturing those markers requires the placement of cortex-optimized electrodes in addition to standard electrodes for DBS. In this Perspective we argue that the need for cortical biomarkers in adaptive DBS and the unfortunate convergence of regulatory and financial factors underpinning the unavailability of cortical electrodes for chronic uses threatens to slow down or stall research on adaptive DBS and propose public-private partnerships as a potential solution to such a critical technological gap.

Abnormal individualized functional connectivity: A potential stimulation target for pediatric tourette syndrome

OBJECTIVE

In order to examine whether individualized peak functional connectivity could potentially serve as a target for repetitive transcranial magnetic stimulation (rTMS) therapy, we investigated the location of peak functional connectivity (FC) between the cortical motor area and the key brain region, the globus pallidus internus (GPi), in Tourette syndrome, and explored the relationship between the severity of the disease and these aberrant functional connections.

METHODS

The study involved a cohort of 103 children diagnosed with Tourette syndrome and 66 age-matched typically developing children. The GPi was served as the seed, and the study compared individualized peak FC strength in the supplementary motor area (SMA) and premotor area between the two groups. Spatial distribution of peak FC in the motor area and GPi-based voxel-wise FC were also analyzed.

RESULTS

Children with Tourette syndrome exhibited lower peak FC in the left SMA when using left GPi as the seed. This reduction in peak FC demonstrated a significant and negative correlation with the Yale Global Tic Severity Scale scores.

CONCLUSIONS

SMA-GPi FC is one of the key pathological circuit in Tourette syndrome.

SIGNIFICANCE

The individual peak FC location in the left SMA potentially serve as stimulation targets for rTMS treatment of TS.

Utilizing Centromedian Thalamus Connectivity to Personalize Noninvasive Neuromodulation Targets

INTRODUCTION

The centromedian nucleus (CM) of the thalamus is essential for arousal, attention, sensory processing, and motor control. Neuromodulation targeting CM dysfunction has shown efficacy in various neurological disorders. However, its individualized precise transcranial magnetic stimulation (TMS) remains unreported. Using resting-state functional MRI, we mapped CM-based functional connectivity (CM-FC) to develop a personalized TMS scheme for neurological conditions.

METHODS

We first analyzed the CM-FC patterns of healthy subjects via 10 scanning sessions in three MRI scanners spanning two subject groups: one from the Human Connectome Project (n = 20, four sessions) dataset and the other from Hangzhou Normal University (n = 20, three sessions of 3 T MRI and three sessions of 1.5 T MRI). Pearson's correlation was used for CM-FC evaluation. Then, we proposed an overlapping index ranging from 1 to 10, and group-level clusters with the highest overlapping index located 4 cm beneath the scalp were identified. In the individual CM-FC map, watershed image segmentation was used to obtain an individual cluster. The peak voxel with the highest FC value within the individual cluster was defined as a potential individualized target for future TMS.

RESULTS

The spatial FC patterns were remarkably similar between the left and right CMs. CMs have widespread positive connectivity with cortical areas, including the sensorimotor cortex, supplementary motor area, middle frontal cortex, medial temporal cortex, and middle cingulate. Among the group-level FC patterns of the left and right CMs, only the left CM had a group cluster in the left primary sensorimotor cortex (PSMC, cluster size = 51) with an overlapping index of 10, that is, 10 sessions showed significant CM-FC.

CONCLUSIONS

The left PSMC exhibited reproducible FC with the left CM. The individual peak FC location in the left PSMC could be used as a TMS target for indirect modulation of CM activity and aid in the treatment of CM-related neurological disorders.

Randomized Controlled Trial of Transcranial Direct Current Stimulation over the Supplementary Motor Area in Tourette Syndrome

BACKGROUND

Transcranial direct current stimulation (tDCS) over the supplementary motor area (SMA) has shown promise in Tourette syndrome (TS), but previous studies were limited in size and stimulation duration.

OBJECTIVE

The aim was to explore the efficacy and safety of multiple sessions of cathodal tDCS over the bilateral SMA on tic severity in TS.

METHODS

A double-blind, randomized, sham-controlled trial 1 mA cathodal tDCS over bilateral SMA was performed in participants with TS older than 16 years. The intervention involved two 20-min periods of stimulation with either sham or active tDCS per day, over 5 consecutive days, during which participants actively suppressed tics. Tic severity was measured using the Yale Global Tic Severity Scale Total Tic Severity (YGTSS-TTS, primary outcome) score at baseline, day 5 (visit 5), and 1 week later (visit 6). Questionnaires focusing on comorbidities were performed at baseline and visit 6.

RESULTS

Twenty-four participants were randomly assigned (12 active, 12 sham; 8 women; median age: 26). We observed a significant effect of visit on YGTSS-TSS, but no significant effect of treatment or treatment × visit interaction emerged. In contrast, a statistically significant effect of the treatment × visit interaction was observed for the motor tic subscore, with significantly larger improvement in the active arm. Furthermore, we detected a significantly larger decrease in premonitory urge intensity at visit 6 after active stimulation. No effect was detected on severity of comorbidities.

CONCLUSIONS

This preliminary study suggests that bilateral tDCS over the SMA provides small, but significant benefits in reducing motor tic severity in TS.

Individual contralesional recruitment in the context of structural reserve in early motor reorganization after stroke

The concept of structural reserve in stroke reorganization assumes that the relevance of the contralesional hemisphere strongly depends on the brain tissue spared by the lesion in the affected hemisphere. Recent studies, however, have indicated that the contralesional hemisphere's impact exhibits region-specific variability with concurrently existing maladaptive and supportive influences. This challenges traditional views, necessitating a nuanced investigation of contralesional motor areas and their interaction with ipsilesional networks. Our study focused on the functional role of contralesional key motor areas and lesion-induced connectome disruption early after stroke. Online TMS data of twenty-five stroke patients was analyzed to disentangle interindividual differences in the functional roles of contralesional primary motor cortex (M1), dorsal premotor cortex (dPMC), and anterior interparietal sulcus (aIPS) for motor function. Connectome-based lesion symptom mapping and corticospinal tract lesion quantification were used to investigate how TMS effects depend on ipsilesional structural network properties. At group and individual levels, TMS interference with contralesional M1 and aIPS but not dPMC led to improved performance early after stroke. At the connectome level, a more disturbing role of contralesional M1 was related to a more severe disruption of the structural integrity of ipsilesional M1 in the affected motor network. In contrast, a detrimental influence of contralesional aIPS was linked to less disruption of the ipsilesional M1 connectivity. Our findings indicate that contralesional areas distinctively interfere with motor performance early after stroke depending on ipsilesional structural integrity, extending the concept of structural reserve to regional specificity in recovery of function.

Deep brain stimulation for Tourette's syndrome

Tourette's syndrome is a neuropsychiatric disorder characterized by formidable motor and vocal tics. Many individuals also present with comorbid neuropsychiatric conditions. Though patients often benefit from pharmacological and behavioral therapies, a subset of individuals develop severe, treatment-resistant symptoms that might necessitate more invasive interventions, such as Deep Brain Stimulation (DBS). DBS, particularly targeting regions like the globus pallidus internus (GPi) and the centromedian-parafascicular complex (CM-Pf) of the thalamus, has demonstrated effectiveness in reducing tic severity and improving quality of life. This review outlines the mechanism, clinical efficacy, and long-term outcome of DBS in TS. Results from clinical studies reveal significant reductions in tics. However, success with DBS is variable depending on a number of factors, including target selection and electrode placement. The use of DBS has ethical considerations, which include risks to the surgical procedure, the need for full and complete informed consent, and questions about the implications of such treatment on cognitive and emotional growth. Long-term follow-up will be required to ensure appropriate patient outcomes and complication management. Additional research and ethical debate will be needed with advancing DBS technology to ensure responsible and equitable treatment. This paper narratively summarizes the surgical options available for TS, with a focus on the current status of DBS in the management of the disease.

Ethics of deep brain stimulation for neuropsychiatric disorders

Deep Brain Stimulation (DBS) has emerged as a revolutionary neurosurgical technique with significant implications for the treatment of various neuropsychiatric disorders. Initially developed for movement disorders like Parkinson's disease, DBS has expanded to psychiatric conditions such as obsessive-compulsive disorder, depression, anorexia nervosa, dystonia, essential tremor, and Tourette's syndrome. This paper explores the clinical efficacy and ethical considerations of DBS in treating these disorders. While DBS has shown substantial promise in alleviating symptoms and improving quality of life, it raises ethical challenges, including issues of informed consent, patient selection, long-term management, and equitable access to treatment. The irreversible nature of DBS, potential adverse effects, and the high cost of the procedure necessitate a rigorous ethical framework to guide its application. The ongoing evolution of neuromodulation requires continuous ethical analysis and the development of guidelines to ensure that DBS is used responsibly and equitably across different patient populations. This paper underscores the need for a balanced approach that integrates clinical efficacy with ethical considerations to optimize patient outcomes and ensure sustainable practice.

Cost-Effectiveness Analysis of Deep Brain Stimulation for the Treatment of Alcohol Use Disorder and Alcoholic Liver Disease

Background

Alcohol use disorder (AUD) is a major public health concern and cause of mortality and morbidity. Alcohol-associated liver disease (ALD) is a debilitating complication of AUD, mitigated by abstinence from alcohol use. Deep brain stimulation (DBS) is emerging as a potential treatment for AUD. However, its cost-effectiveness compared to the standard medical treatment is unclear.

Objective

To estimate the cost-effectiveness of DBS compared to medical management for patients with AUD and ALD.

Methods

We utilized a decision analytic model based on published literature to conduct a cost-effectiveness analysis of costs and health outcomes for DBS and medical management in patients with AUD and ALD. We also carried out a threshold analysis to determine the probability of success necessary for DBS to be cost-effective. Costs were measured in 2024 US dollars and effectiveness in quality-adjusted life years (QALYs). We used a time horizon of 1-2 years and adopted a societal perspective.

Results

Our results show that for AUD patients in general, DBS is not cost-effective at any DBS success rate. However, for advanced ALD patients, defined as fibrosis stage 3 or beyond DBS becomes cost-effective. For these patients, DBS is cost-effective over a two-year period at a $100,000 willingness-to-pay threshold at DBS success rates greater than 53%. For advanced decompensated ALD patients, DBS is cost-effective over a one-year period at DBS success rate greater than 35%.

Conclusion

Should it prove efficacious, DBS may be cost-effective for patients with AUD and ALD. Thus, future randomized controlled trials to evaluate its efficacy are warranted.

Deep brain stimulation for Tourette's syndrome

OBJECTIVES

This is a protocol for a Cochrane Review (intervention). The objectives are as follows: To assess the efficacy and harm of deep brain stimulation for motor symptoms, with psychiatric and behavioural comorbidities, either individually or in combination, in adults and adolescents with Tourette's syndrome compared to placebo, sham intervention, or the best available behavioural and pharmacological treatment.

Clinical neurophysiology in the treatment of movement disorders: IFCN handbook chapter

In this review, different aspects of the use of clinical neurophysiology techniques for the treatment of movement disorders are addressed. First of all, these techniques can be used to guide neuromodulation techniques or to perform therapeutic neuromodulation as such. Neuromodulation includes invasive techniques based on the surgical implantation of electrodes and a pulse generator, such as deep brain stimulation (DBS) or spinal cord stimulation (SCS) on the one hand, and non-invasive techniques aimed at modulating or even lesioning neural structures by transcranial application. Movement disorders are one of the main areas of indication for the various neuromodulation techniques. This review focuses on the following techniques: DBS, repetitive transcranial magnetic stimulation (rTMS), low-intensity transcranial electrical stimulation, including transcranial direct current stimulation (tDCS) and transcranial alternating current stimulation (tACS), and focused ultrasound (FUS), including high-intensity magnetic resonance-guided FUS (MRgFUS), and pulsed mode low-intensity transcranial FUS stimulation (TUS). The main clinical conditions in which neuromodulation has proven its efficacy are Parkinson's disease, dystonia, and essential tremor, mainly using DBS or MRgFUS. There is also some evidence for Tourette syndrome (DBS), Huntington's disease (DBS), cerebellar ataxia (tDCS), and axial signs (SCS) and depression (rTMS) in PD. The development of non-invasive transcranial neuromodulation techniques is limited by the short-term clinical impact of these techniques, especially rTMS, in the context of very chronic diseases. However, at-home use (tDCS) or current advances in the design of closed-loop stimulation (tACS) may open new perspectives for the application of these techniques in patients, favored by their easier use and lower rate of adverse effects compared to invasive or lesioning methods. Finally, this review summarizes the evidence for keeping the use of electromyography to optimize the identification of muscles to be treated with botulinum toxin injection, which is indicated and widely performed for the treatment of various movement disorders.

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.

Emerging therapies for childhood-onset movement disorders

PURPOSE OF REVIEW

We highlight novel and emerging therapies in the treatment of childhood-onset movement disorders. We structured this review by therapeutic entity (small molecule drugs, RNA-targeted therapeutics, gene replacement therapy, and neuromodulation), recognizing that there are two main approaches to treatment: symptomatic (based on phenomenology) and molecular mechanism-based therapy or 'precision medicine' (which is disease-modifying).

RECENT FINDINGS

We highlight reports of new small molecule drugs for Tourette syndrome, Friedreich's ataxia and Rett syndrome. We also discuss developments in gene therapy for aromatic l-amino acid decarboxylase deficiency and hereditary spastic paraplegia, as well as current work exploring optimization of deep brain stimulation and lesioning with focused ultrasound.

SUMMARY

Childhood-onset movement disorders have traditionally been treated symptomatically based on phenomenology, but focus has recently shifted toward targeted molecular mechanism-based therapeutics. The development of precision therapies is driven by increasing capabilities for genetic testing and a better delineation of the underlying disease mechanisms. We highlight novel and exciting approaches to the treatment of genetic childhood-onset movement disorders while also discussing general challenges in therapy development for rare diseases. We provide a framework for molecular mechanism-based treatment approaches, a summary of specific treatments for various movement disorders, and a clinical trial readiness framework.

Comparison of children and adults in deep brain stimulation for Tourette Syndrome: a large-scale multicenter study of 102 cases with long-term follow-up

BACKGROUND

Deep brain stimulation (DBS) is a promising therapy for refractory Gilles de la Tourette syndrome (GTS). However, its long-term efficacy, safety, and recommended surgical age remain controversial, requiring evidence to compare different age categories.

METHODS

This retrospective cohort study recruited 102 GTS patients who underwent DBS between October 2006 and April 2022 at two national centers. Patients were divided into two age categories: children (aged < 18 years; n = 34) and adults (aged ≥ 18 years; n = 68). The longitudinal outcomes as tic symptoms were assessed by the YGTSS, and the YBOCS, BDI, and GTS-QOL were evaluated for symptoms of obsessive-compulsive disorder (OCD), depression, and quality of life, respectively.

RESULTS

Overall, these included patients who finished a median 60-month follow-up, with no significant difference between children and adults (p = 0.44). Overall, the YGTSS total score showed significant postoperative improvements and further improved with time (improved 45.2%, 51.6%, 55.5%, 55.6%, 57.8%, 61.4% after 6, 12, 24, 36, 48, and ≥ 60 months of follow-up compared to baseline, respectively) in all included patients (all p < 0.05). A significantly higher improvement was revealed in children than adults at ≥ 60 months of follow-up in the YGTSS scores (70.1% vs 55.9%, p = 0.043), and the time to achieve 60% improvement was significantly shorter in the children group (median 6 months vs 12 months, p = 0.013). At the last follow-up, the mean improvements were 45.4%, 48.9%, and 55.9% and 40.3%, 45.4%, and 47.9% in YBOCS, BDI, and GTS-QOL scores for children and adults, respectively, which all significantly improved compared to baseline (all p < 0.05) but without significant differences between these two groups (all p > 0.05), and the children group received significantly higher improvement in GTS-QOL scores than adults (55.9% vs. 47.9%, p = 0.049).

CONCLUSIONS

DBS showed acceptable long-term efficacy and safety for both children and adults with GTS. Surgeries performed for patients younger than 18 years seemed to show acceptable long-term efficacy and safety and were not associated with increased risks of loss of benefit compared to patients older than 18 at the time of surgery. However, surgeries for children should also be performed cautiously to ensure their refractoriness and safety.

The role of neuroactive steroids in tic disorders

Tics are sudden, repetitive movements or vocalizations. Tic disorders, such as Tourette syndrome (TS), are contributed by the interplay of genetic risk factors and environmental variables, leading to abnormalities in the functioning of the cortico-striatal-thalamo-cortical (CSTC) circuitry. Various neurotransmitter systems, such as gamma-aminobutyric acid (GABA) and dopamine, are implicated in the pathophysiology of these disorders. Building on the evidence that tic disorders are predominant in males and exacerbated by stress, emerging research is focusing on the involvement of neuroactive steroids, including dehydroepiandrosterone sulfate (DHEAS) and allopregnanolone, in the ontogeny of tics and other phenotypes associated with TS. Emerging evidence indicates that DHEAS levels are significantly elevated in the plasma of TS-affected boys, and the clinical onset of this disorder coincides with the period of adrenarche, the developmental stage characterized by a surge in DHEAS synthesis. On the other hand, allopregnanolone has garnered particular attention for its potential to mediate the adverse effects of acute stress on the exacerbation of tic severity and frequency. Notably, both neurosteroids act as key modulators of GABA-A receptors, suggesting a pivotal role of these targets in the pathophysiology of various clinical manifestations of tic disorders. This review explores the potential mechanisms by which these and other neuroactive steroids may influence tic disorders and discusses the emerging therapeutic strategies that target neuroactive steroids for the management of tic disorders.

Efficacy and safety of combined deep brain stimulation with capsulotomy for comorbid motor and psychiatric symptoms in Tourette's syndrome: Experience and evidence

OBJECTIVES

To evaluate the efficacy and safety of combined deep brain stimulation (DBS) with capsulotomy for comorbid motor and psychiatric symptoms in patients with Tourette's syndrome (TS).

METHODS

This retrospective cohort study consecutively enrolled TS patients with comorbid motor and psychiatric symptoms who were treated with combined DBS and anterior capsulotomy at our center. Longitudinal motor, psychiatric, and cognitive outcomes and quality of life were assessed. In addition, a systematic review and meta-analysis were performed to summarize the current experience with the available evidence.

RESULTS

In total, 5 eligible patients in our cohort and 26 summarized patients in 6 cohorts were included. After a mean 18-month follow-up, our cohort reported that motor symptoms significantly improved by 62.4 % (P = 0.005); psychiatric symptoms of obsessive-compulsive disorder (OCD) and anxiety significantly improved by 87.7 % (P < 0.001) and 78.4 % (P = 0.009); quality of life significantly improved by 61.9 % (P = 0.011); and no significant difference was found in cognitive function (all P > 0.05). Combined surgery resulted in greater improvements in psychiatric outcomes and quality of life than DBS alone. The synthesized findings suggested significant improvements in tics (MD: 57.92, 95 % CI: 41.28-74.56, P < 0.001), OCD (MD: 21.91, 95 % CI: 18.67-25.15, P < 0.001), depression (MD: 18.32, 95 % CI: 13.26-23.38, P < 0.001), anxiety (MD: 13.83, 95 % CI: 11.90-15.76, P < 0.001), and quality of life (MD: 48.22, 95 % CI: 43.68-52.77, P < 0.001). Individual analysis revealed that the pooled treatment effects on motor symptoms, psychiatric symptoms, and quality of life were 78.6 %, 84.5-87.9 %, and 83.0 %, respectively. The overall pooled rate of adverse events was 50.0 %, and all of these adverse events were resolved or alleviated with favorable outcomes.

CONCLUSIONS

Combined DBS with capsulotomy is effective for relieving motor and psychiatric symptoms in TS patients, and its safety is acceptable. However, the optimal candidate should be considered, and additional experience is still necessary.

Diffusion and functional MRI in surgical neuromodulation

Surgical neuromodulation has witnessed significant progress in recent decades. Notably, deep brain stimulation (DBS), delivered precisely within therapeutic targets, has revolutionized the treatment of medication-refractory movement disorders and is now expanding for refractory psychiatric disorders, refractory epilepsy, and post-stroke motor recovery. In parallel, the advent of incisionless treatment with focused ultrasound ablation (FUSA) can offer patients life-changing symptomatic relief. Recent research has underscored the potential to further optimize DBS and FUSA outcomes by conceptualizing the therapeutic targets as critical nodes embedded within specific brain networks instead of strictly anatomical structures. This paradigm shift was facilitated by integrating two imaging modalities used regularly in brain connectomics research: diffusion MRI (dMRI) and functional MRI (fMRI). These advanced imaging techniques have helped optimize the targeting and programming techniques of surgical neuromodulation, all while holding immense promise for investigations into treating other neurological and psychiatric conditions. This review aims to provide a fundamental background of advanced imaging for clinicians and scientists, exploring the synergy between current and future approaches to neuromodulation as they relate to dMRI and fMRI capabilities. Focused research in this area is required to optimize existing, functional neurosurgical treatments while serving to build an investigative infrastructure to unlock novel targets to alleviate the burden of other neurological and psychiatric disorders.

Severe Refractory Obsessive Compulsive Disorder and Depression: Should We Consider Stereotactic Neurosurgery?

Functional neurosurgery involves modulation of activity within neural circuits that drive pathological activity. Neurologists and neurosurgeons have worked closely together, advancing the field for over a century, such that neurosurgical procedures for movement disorders are now accepted as "standard of care", benefiting hundreds of thousands of patients. As with movement disorders, some neuropsychiatric illnesses, including obsessive compulsive disorder and depression, can be framed as disorders of neural networks. Over the past two decades, evidence has accumulated that stereotactic neurosurgery can help some patients with mental disorders. Nevertheless, despite the availability of class I evidence for some interventions, there is a huge mismatch between the prevalence of severe refractory mental disorders and the number of referrals made to specialised functional neurosurgery services. This paper examines the historical trajectory of neurosurgery for movement and mental disorders. A review of neurosurgical techniques, including stereotactic radiofrequency ablation, gamma knife, deep brain stimulation, and magnetic resonance imaging guided focused ultrasound, explains the high degree of safety afforded by technological advances in the field. Evidence from clinical trials supporting functional neurosurgery for mental disorders, including obsessive compulsive disorder and depression, is presented. An improved understanding of modern functional neurosurgery should foster collaboration between psychiatry and neurosurgery, providing hope to patients whose symptoms are refractory to all other treatments.

Pharmacological treatment of Tourette's syndrome: from the past to the future

Tourette's syndrome (TS) is a neuropsychiatric disease featuring tics and vocal tics, with a prevalence of approximately 1%, including 75% of the total number of male patients. TS seriously disturbs the patients' career, education, and life and brings a serious and unbearable psychological burden to the patients themselves and their families. At present, there are no specific clinical medications recommended for treating TS. Therefore, it is necessary to select the appropriate medication for symptomatic treatment based on the doctor's personal experience and the patient's symptoms, with the main goal of relieving symptoms, thus improving the patient's social skills and psychological problems. Here we conducted a comprehensive search on PubMed to review and organize the history and current status of the development of drug therapy for TS through a timeline format. We also systematically evaluated the effects of each drug for TS treatment to summarize the current problems and new research directions and to provide some ideas for clinical treatment.

Placebo and Nocebo Responses in Pharmacological Trials of Tic Disorders: A Meta-Analysis

BACKGROUND

Clinical trials of new drugs for tic disorders (TD) often fail to yield positive results. Placebo and nocebo responses play a vital role in interpreting the outcomes of randomized controlled trials (RCTs), yet these responses in RCTs of TD remain unexplored.

OBJECTIVE

The aim was to assess the magnitude of placebo and nocebo responses in RCTs of pharmacological interventions for TD and identify influencing factors.

METHODS

A systematic search of the Embase, Medline, Cochrane Central Register of Controlled Trials, and PsycINFO databases was conducted. Eligible studies were RCTs that compared active pharmacological agents with placebos. Placebo response was defined as the change from baseline in TD symptom severity in the placebo group, and nocebo response as the proportion experiencing adverse events (AEs) in this group. Subgroup analysis and meta-regression were performed to explore modifying factors.

RESULTS

Twenty-four trials involving 2222 participants were included in this study. A substantial placebo response in TD symptom severity was identified, with a pooled effect size of -0.79 (95% confidence interval [CI] -0.99 to -0.59; I2 = 67%). Forty-four percent (95% CI 27% to 63%; I2 = 92%) of patients experienced AEs while taking inert pills. Sample size, study design, and randomization ratio were correlated with changes in placebo and nocebo responses.

CONCLUSION

There were considerable placebo and nocebo responses in TD clinical trials. These results are of great relevance for the design of future trials and for clinical practice in TD.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO registration ID CRD42023388397. © 2024 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.

Symptomatic Treatment of Extrapyramidal Hyperkinetic Movement Disorders

Extrapyramidal hyperkinetic movement disorders comprise a broad range of phenotypic phenomena, including chorea, dystonia, and tics. Treatment is generally challenging and individualized, given the overlapping phenomenology, limited evidence regarding efficacy, and concerns regarding the tolerability and safety of most treatments. Over the past decade, the treatment has become even more intricate due to advancements in the field of deep brain stimulation as well as optimized dopamine- depleting agents. Here, we review the current evidence for treatment modalities of extrapyramidal hyperkinetic movement disorders and provide a comprehensive and practical overview to aid the choice of therapy. Mechanism of action and practical intricacies of each treatment modality are discussed, focusing on dosing and adverse effect management. Finally, future therapeutic developments are also discussed.

One-year outcomes of deep brain stimulation in refractory Tourette syndrome

AIM

Deep brain stimulation (DBS) is one option for treating refractory Tourette syndrome (TS); however, it remains unclear which preoperative factors are predictive of DBS outcomes. This study investigated the efficacy of DBS targeting the anteromedial globus pallidus internus and evaluated predisposing factors affecting the outcomes of DBS in a single center in Korea.

METHOD

Twenty patients who had undergone DBS for refractory TS were reviewed retrospectively. Tic symptoms were followed up at 3-month intervals for up to 1 year after surgery. The Yale Global Tic Severity Scale was used to evaluate preoperative/postoperative tic symptoms. Scores from the Yale-Brown Obsessive Compulsive Scale, Beck Depression Inventory-II, and Beck Anxiety Inventory were also evaluated.

RESULTS

Patients with refractory TS achieved improvement in tic symptoms within 1 year after DBS. Initial responders who achieved a 35% reduction in Yale Global Tic Severity Scale total score within the first 3 months after DBS showed larger treatment effects during 1-year follow-up. Although no clinical or demographic factors were predictive of initial responses, patients with serious self-injurious behaviors tended to show delayed responses.

CONCLUSION

This is the first study to our knowledge to report the DBS outcomes of 20 patients with TS in a single center in Asia. Our study supports the efficacy of DBS targeting anteromedial globus pallidus internus in refractory TS with no evident serious adverse events. Initial responses after DBS seem to be a predictor of long-term outcomes after surgery.

An Update on the Diagnosis and Management of Tic Disorders

Tic disorders (TDs) are a group of common neuropsychiatric disorders of childhood and adolescence. TDs may impact the physical, emotional, and social well-being of the affected person. In this review, we present an update on the clinical manifestations, pathophysiology, diagnosis, and treatment of TDs. We searched the PubMed database for articles on tics and Tourette syndrome. More than 400 articles were reviewed, of which 141 are included in this review. TDs are more prevalent in children than in adults and in males than in females. It may result from a complex interaction between various genetic, environmental, and immunological factors. Dysregulation in the cortico-striato-pallido-thalamo-cortical network is the most plausible pathophysiology resulting in tics. TD is a clinical diagnosis based on clinical features and findings on neurological examination, especially the identification of tic phenomenology. In addition to tics, TD patients may have sensory features, including premonitory urge; enhanced and persistent sensitivity to non-noxious external or internal stimuli; and behavioral manifestations, including attention deficit hyperactivity disorders, obsessive-compulsive disorders, and autism spectrum disorders. Clinical findings of hyperkinetic movements that usually mimic tics have been compared and contrasted with those of TD. Patients with TD may not require specific treatment if tics are not distressing. Psychoeducation and supportive therapy can help reduce tics when combined with medication. Dispelling myths and promoting acceptance are important to improve patient outcomes. Using European, Canadian, and American guidelines, the treatment of TD, including behavioral therapy, medical therapy, and emerging/experimental therapy, has been discussed.

Spatially specific, closed-loop infrared thalamocortical deep brain stimulation

Deep brain stimulation (DBS) is a powerful tool for the treatment of circuitopathy-related neurological and psychiatric diseases and disorders such as Parkinson's disease and obsessive-compulsive disorder, as well as a critical research tool for perturbing neural circuits and exploring neuroprostheses. Electrically-mediated DBS, however, is limited by the spread of stimulus currents into tissue unrelated to disease course and treatment, potentially causing undesirable patient side effects. In this work, we utilize infrared neural stimulation (INS), an optical neuromodulation technique that uses near to mid-infrared light to drive graded excitatory and inhibitory responses in nerves and neurons, to facilitate an optical and spatially constrained DBS paradigm. INS has been shown to provide spatially constrained responses in cortical neurons and, unlike other optical techniques, does not require genetic modification of the neural target. We show that INS produces graded, biophysically relevant single-unit responses with robust information transfer in thalamocortical circuits. Importantly, we show that cortical spread of activation from thalamic INS produces more spatially constrained response profiles than conventional electrical stimulation. Owing to observed spatial precision of INS, we used deep reinforcement learning for closed-loop control of thalamocortical circuits, creating real-time representations of stimulus-response dynamics while driving cortical neurons to precise firing patterns. Our data suggest that INS can serve as a targeted and dynamic stimulation paradigm for both open and closed-loop DBS.

Precision Mapping of Thalamic Deep Brain Stimulation Lead Positions Associated With the Microlesion Effect in Tourette Syndrome

BACKGROUND

The microlesion effect refers to the improvement of clinical symptoms after deep brain stimulation (DBS) lead placement and is suggested to indicate optimal lead placement. Very few studies have reported its implications in neuropsychiatric disorders.

OBJECTIVE

To evaluate the magnitude of the microlesion effect in Tourette syndrome and the relationship between the microlesion effect and the anatomic location of implanted DBS leads.

METHODS

Six male patients were included. Their median age at surgery and follow-up period were 25 years (range, 18-47) and 12 months (range, 6-24), respectively. All patients were videotaped pre- and postoperatively, and tic frequencies were counted. We also analyzed the precision of lead placement and evaluated the normative connectome associated with the microlesion area.

RESULTS

The microlesion effect was observed as an improvement in tic symptoms in all patients, and the long-term clinical outcomes were favorable. The median motor tic frequency was 20.2 tics/min (range, 9.7-60) at baseline and decreased to 3.2 tics/min (1.2-11.3) in patients on postoperative day 1 ( P = .043) and to 5.7 tics/min (range, 1.9-16.6) in patients on postoperative day 7 ( P = .028). Phonic tic tended to improve immediately after surgery although the changes were not significant. Image analyses revealed that the precise position of the electrode was directed toward the anteromedial centromedian nucleus. Normative connectome analysis demonstrated connections between improvement-related areas and wide areas of the prefrontal cortex.

CONCLUSION

This study shows that the microlesion effect may seem as an immediate improvement after optimal DBS lead placement in patients with Tourette syndrome.

Neuromodulation of the anterior thalamus: Current approaches and opportunities for the future

The role of thalamocortical circuits in memory has driven a recent burst of scholarship, especially in animal models. Investigating this circuitry in humans is more challenging. And yet, the development of new recording and stimulation technologies deployed for clinical indications has created novel opportunities for data collection to elucidate the cognitive roles of thalamic structures. These technologies include stereoelectroencephalography (SEEG), deep brain stimulation (DBS), and responsive neurostimulation (RNS), all of which have been applied to memory-related thalamic regions, specifically for seizure localization and treatment. This review seeks to summarize the existing applications of neuromodulation of the anterior thalamic nuclei (ANT) and highlight several devices and their capabilities that can allow cognitive researchers to design experiments to assay its functionality. Our goal is to introduce to investigators, who may not be familiar with these clinical devices, the capabilities, and limitations of these tools for understanding the neurophysiology of the ANT as it pertains to memory and other behaviors. We also briefly cover the targeting of other thalamic regions including the centromedian (CM) nucleus, dorsomedial (DM) nucleus, and pulvinar, with associated potential avenues of experimentation.

Creative thinking in Tourette's syndrome: A comparative study of patients and healthy controls

INTRODUCTION

Tourette's syndrome is a neurological disorder characterized by tics, that may interfere with patients' everyday life. Research suggested that creative thinking (namely, divergent and convergent thinking) could help patients cope with their symptoms, and therefore it can be a resource in non-pharmacological interventions. The present study aimed at investigating (i) possible differences in creative thinking between Tourette's syndrome patients and healthy controls and (ii) whether creative thinking can support patients in coping with their symptomatology.

METHODS

A group of 25 Tourette's syndrome patients and 25 matched healthy controls underwent an assessment of creative thinking, fluid intelligence, and depressive symptoms. Creative thinking was compared between patients and healthy controls after controlling for fluid intelligence and depressive symptoms. Moreover, the moderating role of divergent and convergent thinking on the subjective impact of tics was tested in a group of 30 patients.

RESULTS

Tourette's syndrome patients outperformed healthy controls in convergent thinking. Moreover, divergent thinking was found as a significant moderator of the relationship between tics severity and the subjective impact in Tourette's syndrome patients.

CONCLUSIONS

Findings highlighted the specific impact of convergent and divergent thinking on Tourette's syndrome patients. Considering the supportive role of creative thinking in Tourette's syndrome, our results confirm that higher levels of divergent thinking may reduce the tic-related discomfort. These findings suggest the potential positive implications of creative thinking in non-pharmacological interventions for Tourette's syndrome.

Participant perceptions of changes in psychosocial domains following participation in an adaptive deep brain stimulation trial

BACKGROUND

There has been substantial controversy in the neuroethics literature regarding the extent to which deep brain stimulation (DBS) impacts dimensions of personality, mood, and behavior.

OBJECTIVE/HYPOTHESIS

Despite extensive debate in the theoretical literature, there remains a paucity of empirical data available to support or refute claims related to the psychosocial changes following DBS.

METHODS

A mixed-methods approach was used to examine the perspectives of patients who underwent DBS regarding changes to their personality, authenticity, autonomy, risk-taking, and overall quality of life.

RESULTS

Patients (n = 21) who were enrolled in adaptive DBS trials for Parkinson's disease, essential tremor, obsessive-compulsive disorder, Tourette's syndrome, or dystonia participated. Qualitative data revealed that participants, in general, reported positive experiences with alterations in what was described as 'personality, mood, and behavior changes.' The majority of participants reported increases in quality of life. No participants reported 'regretting the decision to undergo DBS.'

CONCLUSION(S)

The findings from this patient sample do not support the narrative that DBS results in substantial adverse changes to dimensions of personality, mood, and behavior. Changes reported as "negative" or "undesired" were few in number, and transient in nature.

Surgical treatment of movement disorders in neurometabolic conditions

Refractory movement disorders are a common feature of inborn errors of metabolism (IEMs), significantly impacting quality of life and potentially leading to life-threatening complications such as status dystonicus. Surgical techniques, including deep brain stimulation (DBS) and lesioning techniques, represent an additional treatment option. However, the application and benefits of these procedures in neurometabolic conditions is not well understood. This results in challenges selecting surgical candidates and counseling patients preoperatively. In this review, we explore the literature of surgical techniques for the treatment of movement disorders in IEMs. Globus pallidus internus DBS has emerged as a beneficial treatment option for dystonia in Panthotate-Kinase-associated Neurodegeneration. Additionally, several patients with Lesch-Nyhan Disease have shown improvement following pallidal stimulation, with more robust effects on self-injurious behavior than dystonia. Although there are numerous reports describing benefits of DBS for movement disorders in other IEMs, the sample sizes have generally been small, limiting meaningful conclusions. Currently, DBS is preferred to lesioning techniques. However, successful use of pallidotomy and thalamotomy in neurometabolic conditions has been reported and may have a role in selected patients. Surgical techniques have also been used successfully in patients with IEMs to treat status dystonicus. Advancing our knowledge of these treatment options could significantly improve the care for patients with neurometabolic conditions.

Future directions in psychiatric neurosurgery: Proceedings of the 2022 American Society for Stereotactic and Functional Neurosurgery meeting on surgical neuromodulation for psychiatric disorders

OBJECTIVE

Despite advances in the treatment of psychiatric diseases, currently available therapies do not provide sufficient and durable relief for as many as 30-40% of patients. Neuromodulation, including deep brain stimulation (DBS), has emerged as a potential therapy for persistent disabling disease, however it has not yet gained widespread adoption. In 2016, the American Society for Stereotactic and Functional Neurosurgery (ASSFN) convened a meeting with leaders in the field to discuss a roadmap for the path forward. A follow-up meeting in 2022 aimed to review the current state of the field and to identify critical barriers and milestones for progress.

DESIGN

The ASSFN convened a meeting on June 3, 2022 in Atlanta, Georgia and included leaders from the fields of neurology, neurosurgery, and psychiatry along with colleagues from industry, government, ethics, and law. The goal was to review the current state of the field, assess for advances or setbacks in the interim six years, and suggest a future path forward. The participants focused on five areas of interest: interdisciplinary engagement, regulatory pathways and trial design, disease biomarkers, ethics of psychiatric surgery, and resource allocation/prioritization. The proceedings are summarized here.

CONCLUSION

The field of surgical psychiatry has made significant progress since our last expert meeting. Although weakness and threats to the development of novel surgical therapies exist, the identified strengths and opportunities promise to move the field through methodically rigorous and biologically-based approaches. The experts agree that ethics, law, patient engagement, and multidisciplinary teams will be critical to any potential growth in this area.

Lesion-network mapping for tics: moving from replication to clinical translation

This scientific commentary refers to 'Mapping a network for tics in Tourette syndrome using causal lesions and structural alterations', by Zouki et al. (https://doi.org/10.1093/braincomms/fcad105).

Mapping a network for tics in Tourette syndrome using causal lesions and structural alterations

Tics are sudden stereotyped movements or vocalizations. Cases of lesion-induced tics are invaluable, allowing for causal links between symptoms and brain structures. While a lesion network for tics has recently been identified, the degree to which this network translates to Tourette syndrome has not been fully elucidated. This is important given that patients with Tourette syndrome make up a large portion of tic cases; therefore, existing and future treatments should apply to these patients. The aim of this study was to first localize a causal network for tics from lesion-induced cases and then refine and validate this network in patients with Tourette syndrome. We independently performed 'lesion network mapping' using a large normative functional connectome (n = 1000) to isolate a brain network commonly connected to lesions causing tics (n = 19) identified through a systematic search. The specificity of this network to tics was assessed through comparison to lesions causing other movement disorders. Using structural brain coordinates from prior neuroimaging studies (n = 7), we then derived a neural network for Tourette syndrome. This was done using standard anatomical likelihood estimation meta-analysis and a novel method termed 'coordinate network mapping', which uses the same coordinates, yet maps their connectivity using the aforementioned functional connectome. Conjunction analysis was used to refine the network for lesion-induced tics to Tourette syndrome by identifying regions common to both lesion and structural networks. We then tested whether connectivity from this common network is abnormal in a separate resting-state functional connectivity MRI data set from idiopathic Tourette syndrome patients (n = 21) and healthy controls (n = 25). Results showed that lesions causing tics were distributed throughout the brain; however, consistent with a recent study, these were part of a common network with predominant basal ganglia connectivity. Using conjunction analysis, coordinate network mapping findings refined the lesion network to the posterior putamen, caudate nucleus, globus pallidus externus (positive connectivity) and precuneus (negative connectivity). Functional connectivity from this positive network to frontal and cingulate regions was abnormal in patients with idiopathic Tourette syndrome. These findings identify a network derived from lesion-induced and idiopathic data, providing insight into the pathophysiology of tics in Tourette syndrome. Connectivity to our cortical cluster in the precuneus offers an exciting opportunity for non-invasive brain stimulation protocols.

Interactive mobile application for Parkinson's disease deep brain stimulation (MAP DBS): An open-label, multicenter, randomized, controlled clinical trial

INTRODUCTION

Deep brain stimulation (DBS) is an effective treatment for Parkinson's disease (PD), but its efficacy is tied to DBS programming, which is often time consuming and burdensome for patients, caregivers, and clinicians. Our aim is to test whether the Mobile Application for PD DBS (MAP DBS), a clinical decision support system, can improve programming.

METHODS

We conducted an open-label, 1:1 randomized, controlled, multicenter clinical trial comparing six months of SOC standard of care (SOC) to six months of MAP DBS-aided programming. We enrolled patients between 30 and 80 years old who received DBS to treat idiopathic PD at six expert centers across the United States. The primary outcome was time spent DBS programming and secondary outcomes measured changes in motor symptoms, caregiver strain and medication requirements.

RESULTS

We found a significant reduction in initial visit time (SOC: 43.8 ± 28.9 min n = 37, MAP DBS: 27.4 ± 13.0 min n = 35, p = 0.001). We did not find a significant difference in total programming time between the groups over the 6-month study duration. MAP DBS-aided patients experienced a significantly larger reduction in UPDRS III on-medication scores (-7.0 ± 7.9) compared to SOC (-2.7 ± 6.9, p = 0.01) at six months.

CONCLUSION

MAP DBS was well tolerated and improves key aspects of DBS programming time and clinical efficacy.

"Unvoluntary" Movement Disorders: Distinguishing between Tics, Akathisia, Restless Legs, and Stereotypies

Tics, stereotypies, akathisia, and restless legs fall at different places on the spectrum of discrete, unwanted and potentially disabling motor routines. Unlike tremor, chorea, myoclonus, or dystonia, this subgroup of abnormal movements is characterized by the subject's variable ability to inhibit or release undesired motor patterns on demand. Though it may be sometimes clinically challenging, it is crucial to distinguish these "unvoluntary" motor behaviors because secondary causes and management approaches differ substantially. To this end, physicians must consider the degree of repetitiveness of the movements, the existence of volitional control, and the association with sensory symptoms, or cognitive-ideational antecedent. This review aims to summarize the current existing knowledge on phenomenology, diagnosis, and treatment of tics, stereotypies, akathisia, and restless leg syndrome.

Surgical Site Infections Associated With Implanted Pulse Generators for Deep Brain Stimulation: Meta-Analysis and Systematic Review

OBJECTIVES

The aim of this study was to identify and systematically analyze relevant literature on surgical site infections (SSIs) associated with implantable pulse generator (IPG) procedures for deep brain stimulation (DBS).

MATERIALS AND METHODS

In compliance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines, we conducted a systematic review and meta-analyses of 58 studies that reported SSI rates of 11,289 patients and 15,956 IPG procedures. A meta-analysis of proportions was performed to estimate the pooled proportion of SSIs across DBS procedures in general and to estimate the proportion of SSIs that occur at the IPG pocket. Moreover, a meta-analysis of odds ratio (OR) was conducted on those studies that reported their results of applying topical vancomycin powder during closure of the IPG wound. Results are presented as rates and OR with 95% CIs.

RESULTS

The pooled proportion of SSIs was 4.9% (95% CI, 4.1%-6.1%) among all DBS procedures. The dominant SSI localization was the IPG pocket in 61.2% (95% CI, 53.4%-68.5%). A trend toward a beneficial effect of vancomycin powder over standard wound closure was found with an OR of 0.46 (95% CI, 0.21-1.02). Most studies (79.1%) that reported their treatment strategy in case of SSI had a strict protocol of removal of the IPG, followed by antimicrobial treatment and reimplantation of the IPG once the SSI had been eradicated.

CONCLUSIONS

The IPG pocket was identified as the main site of SSI after DBS procedures. Most studies recommend complete IPG removal, antimicrobial treatment, and reimplantation of an IPG once the SSI has been eradicated. Future studies are needed to clarify the role of alternative approaches (eg, topical vancomycin powder) in the prevention of SSI associated with IPG.

Tourette syndrome: clinical features, pathophysiology, and treatment

Tourette syndrome is a chronic neurodevelopmental disorder characterised by motor and phonic tics that can substantially diminish the quality of life of affected individuals. Evaluating and treating Tourette syndrome is complex, in part due to the heterogeneity of symptoms and comorbidities between individuals. The underlying pathophysiology of Tourette syndrome is not fully understood, but recent research in the past 5 years has brought new insights into the genetic variations and the alterations in neurophysiology and brain networks contributing to its pathogenesis. Treatment options for Tourette syndrome are expanding with novel pharmacological therapies and increased use of deep brain stimulation for patients with symptoms that are refractory to pharmacological or behavioural treatments. Potential predictors of patient responses to therapies for Tourette syndrome, such as specific networks modulated during deep brain stimulation, can guide clinical decisions. Multicentre data sharing initiatives have enabled several advances in our understanding of the genetics and pathophysiology of Tourette syndrome and will be crucial for future large-scale research and in refining effective treatments.

Tourette syndrome and other tic disorders of childhood

Tics are repetitive, patterned, and nonrhythmic movements or vocalizations/audible sounds that are misplaced in context. Phenomenology and characteristics of tics (e.g., premonitory urge, suppressibility) differentiate them from compulsions, stereotypies, functional tic-like behaviors, and other types of hyperkinetic movement disorders. With a prevalence of approximately 1% in school-aged boys, Tourette syndrome (TS) is considered a common childhood-onset neurodevelopmental disorder, defined by the combination of at least two motor tics and at least one phonic tic lasting more than 1 year. TS is a highly heritable disorder, with a wide spectrum of severity. In some individuals, tics can cause pain, distress, functional impairment, or stigmatization. About 90% of individuals with TS have at least one mental health comorbidity (attention-deficit/hyperactivity disorder, obsessive-compulsive disorder, anxiety/depressive disorders). These comorbidities significantly impact patients' quality of life and must therefore be screened and managed accordingly in this population. Treatment of tics is based on behavioral therapies targeting tics (habit reversal training included in the comprehensive behavioral intervention for tics, and exposure and response prevention for tics), in association with medication if needed (e.g., alpha-2-agonists, second-generation antipsychotics). Deep brain stimulation is considered an experimental option in the most severe, treatment-resistant patients. In adulthood, less than 25% of individuals still have moderate or severe tics.

Trends of Tourette Syndrome in children from 2011 to 2021: A bibliometric analysis

Objective

Analyze the research status of Tourette Syndrome (TS) in children by CiteSpace and determine the current research hotspots and frontiers.

Materials and methods

We chose publications indexed in the Web of Science Core Collection (WoSCC) database for studies related to TS in children from 2011 to 2021. We built online cooperation maps of countries/regions, institutions, authors, journals, references, and keywords by CiteSpace, and identified hotspots and frontiers of study for children’s TS.

Results

A total of 1,232 publications about TS in children were downloaded from the WoSCC. The USA (414) was the country with the highest rate of production, and University College London (87) was the institution that had the highest publication rate. Andrea Eugenio Cavanna was the most prolific author (39 papers). There was inactive cooperation between institutions, countries/regions, and authors. The Journal of European Child &amp; Adolescent Psychiatry was the most active journal. Hot topics focused on epidemiology, comorbidities, deep brain stimulation, behavioral therapy, basal ganglia, pharmacological treatment, and risk factors of TS in children.

Conclusion

According to the CiteSpace results, this study found that authors, countries/regions, and institutions were not actively working together. Current research hotspots mainly consist of epidemiology, comorbidities, deep brain stimulation, behavior therapy, and basal ganglia. The main research trends include comorbidities, pharmacological treatment, and risk factors. Therefore, international cooperation should be strengthened in the future, and it should be mindful of the psychiatric comorbidities of TS, the choice of intervention measures, and early warning of risk factors.

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.

Structural hyperconnectivity of the subthalamic area with limbic cortices underpins anxiety and impulsivity in Tourette syndrome

Tourette syndrome (TS) is a neurodevelopmental disorder characterized by motor and vocal tics, which is often associated with psychiatric comorbidities. Dysfunction of basal ganglia pathways might account for the wide spectrum of symptoms in TS patients. Although psychiatric symptoms may be related to limbic networks, the specific contribution of different limbic structures remains unclear. We used tractography to investigate cortical connectivity with the striatal area (caudate, putamen, core and shell of the nucleus accumbens), the subthalamic nucleus (STN), and the adjacent medial subthalamic region (MSR) in 58 TS patients and 35 healthy volunteers. 82% of TS patients showed psychiatric comorbidities, with significantly higher levels of anxiety and impulsivity compared to controls. Tractography analysis revealed significantly increased limbic cortical connectivity of the left MSR with the entorhinal (BA34), insular (BA48), and temporal (BA38) cortices in TS patients compared to controls. Furthermore, we found that left insular-STN connectivity was positively correlated with impulsivity scores for all subjects and with anxiety scores for all subjects, particularly for TS. Our study highlights a heterogenous modification of limbic structure connectivity in TS, with specific abnormalities found for the subthalamic area. Abnormal connectivity with the insular cortex might underpin the higher level of impulsivity and anxiety observed in TS.

Tics and Tourette Syndrome: A Literature Review of Etiological, Clinical, and Pathophysiological Aspects

Tourette syndrome (TS) is a condition characterized by tics produced because of neuropsychiatric malfunctioning occurring in childhood, which becomes less severe in adulthood, followed by a difference in the severity of tics between two persons. TS is a diverse variable in which symptoms vary in different patients. It is associated with comorbidities like obsessive-compulsive disorder (OCD), attention deficit hyperactivity disorder (ADHD), and depression, and hampers the quality of life. Comorbid disorders must be investigated and treated as part of the clinical approach for all TS patients. Clinicians should be aware of the infrequent but serious neurological problems that can occur in these patients and recommend aggressively treating tics. Currently, there is more emphasis on symptom-based treatments by medicines, but as etiological knowledge improves, we will divert to disease-modifying medications in the future. Behavioral, pharmacological, and surgical methods can treat TS. Neuroleptics, other drugs, and behavioral therapies are the first-line options. Deep brain stimulation is evolving but has its pros and cons. The main focus of this review is on tics characteristics, how to manage and assess them, and limitations in the clinical spectrum.

Clinical characteristics of pediatric patients with treatment-refractory Tourette syndrome: An evidence-based survey in a Chinese population

BACKGROUND

Tourette syndrome (TS) is a complex neurodevelopmental condition marked by tics, as well as a variety of psychiatric comorbidities, such as obsessive-compulsive disorders (OCDs), attention deficit hyperactivity disorder (ADHD), anxiety, and self-injurious behavior. TS might progress to treatment-refractory Tourette syndrome (TRTS) in some patients. However, there is no confirmed evidence in pediatric patients with TRTS.

AIM

To investigate the clinical characteristics of TRTS in a Chinese pediatric sample.

METHODS

A total of 126 pediatric patients aged 6-12 years with TS were identified, including 64 TRTS and 62 non-TRTS patients. The Yale Global Tic Severity Scale (YGTSS), Premonitory Urge for Tics Scale (PUTS), and Child Behavior Checklist (CBCL) were used to assess these two groups and compared the difference between the TRTS and non-TRTS patients.

RESULTS

When compared with the non-TRTS group, we found that the age of onset for TRTS was younger (P < 0.001), and the duration of illness was longer (P < 0.001). TRTS was more often caused by psychosocial (P < 0.001) than physiological factors, and coprolalia and inappropriate parenting style were more often present in the TRTS group (P < 0.001). The TRTS group showed a higher level of premonitory urge (P < 0.001), a lower intelligence quotient (IQ) (P < 0.001), and a higher percentage of family history of TS. The TRTS patients demonstrated more problems (P < 0.01) in the “Uncommunicative”, “Obsessive-Compulsive”, “Social-Withdrawal”, “Hyperactive”, “Aggressive”, and “Delinquent” subscales in the boys group, and “Social-Withdrawal” (P = 0.02) subscale in the girls group.

CONCLUSION

Pediatric TRTS might show an earlier age of onset age, longer duration of illness, lower IQ, higher premonitory urge, and higher comorbidities with ADHD-related symptoms and OCD-related symptoms. We need to pay more attention to the social communication deficits of TRTS.

Advances in DBS Technology and Novel Applications: Focus on Movement Disorders

PURPOSE OF REVIEW

Deep brain stimulation (DBS) is an established treatment in several movement disorders, including Parkinson's disease, dystonia, tremor, and Tourette syndrome. In this review, we will review and discuss the most recent findings including but not limited to clinical evidence.

RECENT FINDINGS

New DBS technologies include novel hardware design (electrodes, cables, implanted pulse generators) enabling new stimulation patterns and adaptive DBS which delivers potential stimulation tailored to moment-to-moment changes in the patient's condition. Better understanding of movement disorders pathophysiology and functional anatomy has been pivotal for studying the effects of DBS on the mesencephalic locomotor region, the nucleus basalis of Meynert, the substantia nigra, and the spinal cord. Eventually, neurosurgical practice has improved with more accurate target visualization or combined targeting. A rising research domain emphasizes bridging neuromodulation and neuroprotection. Recent advances in DBS therapy bring more possibilities to effectively treat people with movement disorders. Future research would focus on improving adaptive DBS, leading more clinical trials on novel targets, and exploring neuromodulation effects on neuroprotection.