Tourette syndrome: clinical features, pathophysiology, and treatment

Exogenous GABA Alleviates Tourette Syndrome-Like Behavior in Sprague-Dawley Rats by Altering Gut Microbiota and Striatum Metabolism

Context

Tourette syndrome (TS) is a common chronic neuropsychiatric disorder with a prevalence of approximately 1% in children and adolescents. TS is characterized by sudden involuntary motor tics along with vocal tics. A pathological study on postmortem patients has reported a 50-60% reduction in striatal gamma-aminobutyric acidergic (GABAergic) interneurons, suggesting a role for GABAergic system imbalances in tic disorder development. However, the effect of exogenous GABA administration on tic alleviation remains unreported.

Objective

In this study, we aim to investigate the therapeutic effects of exogenous GABA on TS-like behaviors in Sprague-Dawley rats and explore its potential mechanisms, including gut microbiota regulation, oxidative stress mitigation, and restoration of GABA-glutamate balance, to provide insights into TS pathogenesis and alternative treatment strategies.

Materials and Methods

A TS model rat was established through intraperitoneal administration of 3,3-Iminodipropionitrile (150 mg/kg/day), followed by GABA (20 mg/kg/day) administration by gavage. 15 minutes of behavioral testing (stereotypical behavior and head twitching behavior) was then conducted. 16S rRNA sequencing identified microbiome changes, and LC-MS assessed striatal metabolite changes.

Results

The results showed that a 4-week GABA treatment alleviated TS-like behavior in rats. GABA treatment led to an increase in Acinetobacter and other beneficial bacteria. GABA also significantly upregulated 15 striatal metabolites compared with TS group. By correlation analysis of striatal metabolites and intestinal bacteria, statistical analysis showed that Clostridium_sensu_stricto_1 was negatively correlated with metabolites on the top 20 differential gut microbiota and metabolites. Moreover, changes in gut microbiota correlated with alterations in striatal metabolites, suggesting a gut-brain axis involvement.

Conclusion

Exogenous GABA alleviated TS-like behavior in rats by reducing harmful gut flora and modulating striatal GABA-glutamate metabolism. Despite challenges like low blood-brain barrier permeability and dose safety in humans, GABA's therapeutic potential may be realized through prodrug development and optimized dosing. These findings are preliminary and require further clinical validation.

Genetic architecture of tic disorders: A systematic review of 125 observational studies

BACKGROUND

To summarize and evaluate recent advances in the genetics of tic disorders (TDs) and to understand the possible pathogenic mechanisms behind this disorder.

METHODS

PubMed, EMBASE, the Cochrane Library, and four Chinese databases were searched from inception to September 2022. Observational original studies that explored genetic or chromosomal variations associated with the etiology, diagnosis, treatment, or prognosis of TDs were included. The Strengthening the Reporting of Genetic Association Studies (STREGA) statement was used to evaluate the quality of the included studies.

RESULTS

125 studies were finally included with 119 of moderate quality and 6 of low quality. A total of 32,439 cases with different types of TDs and 81,923 controls were included. The results involved 98 genes, 16 chromosomes, and multiple gene sets. Genome-wide studies were also included. The top three systems were the dopamine system, nervous system development, and the serotonin system. 96 loci in 56 genes and 20 regions in 14 chromosomes were reported to be relevant to TDs, with SLC6A4 (serotonin system) and NTN4 genes being relatively strongly correlated with the occurrence of TS, and ACP1 (serotonin system) and DBH (dopamine system) being relatively strongly correlated with TS comorbid with attention deficit hyperactivity disorder (ADHD).

CONCLUSION

Polygenic loci were found to play a key role in the occurrence and development of TDs. However, the applicability of the findings may be limited due to the small sample size, single-center design and the limited study quality of included studies. Future research with more comprehensive study designs and improved reporting transparency is needed to confirm the findings.

Effects of micronutrients on neurodevelopmental disorders through the mediation of brain structure and function: A two-step Mendelian randomization analysis

The physiological functions of micronutrients in neurodevelopment are well documented, but their protective effects on neurodevelopmental disorders remain controversial. We assessed the associations between micronutrients and three main neurodevelopmental disorders, that is, autism spectrum disorder (18,381 cases), attention-deficit/hyperactivity disorder (38,691 cases), and Tourette's syndrome (4,819 cases), using two-sample Mendelian randomization analyses. In addition, we estimated the mediation role of brain imaging-derived phenotypes (n = 33,224) in these associations. Each 1 SD (0.08 mmol/L) increase in serum magnesium concentration was associated with a 16% reduced risk of autism spectrum disorder (odds ratio 0.84, 95% confidence interval 0.72-0.98). Each 1 SD (65 μmol/L) increase in blood erythrocyte zinc concentration was associated with an 8% reduced risk of attention-deficit/hyperactivity disorder (0.92, 0.86-0.98). Each 1 SD (173 pmol/L) increase in serum vitamin B12 concentration was associated with a 19% reduced risk of Tourette's syndrome (0.81, 0.68-0.97). These effects were partly mediated by alterations in multiple brain imaging-derived phenotypes, with mediated proportions ranging from 5.84% to 32.66%. Our results suggested that interventions targeting micronutrient deficiencies could be a practical and effective strategy for preventing neurodevelopmental disorders, especially in populations at high risk of malnutrition.Lay abstractIncreasing evidence highlights the critical role of micronutrients in neurodevelopment. However, the causal relationship between micronutrients and neurodevelopmental disorders remains unclear. Using genetic variants associated with micronutrient levels and neurodevelopmental disorders, our study revealed the protective effects of magnesium on autism spectrum disorders, zinc on attention-deficit/hyperactivity disorder, and vitamin B12 on Tourette's syndrome. These protective effects were partially mediated through alterations in brain structure, function, and connectivity. Our findings emphasize the importance of adequate micronutrient intake for healthy neurodevelopment and may support the development of intervention strategies aimed at preventing neurodevelopmental disorders by addressing micronutrient deficiencies.

Integrating behavioral interventions for Tourette's syndrome: Current status and prospective

In the evolving landscape of Tourette's syndrome (TS) treatment, behavioral therapies have emerged as essential to address the comorbid psychological issues, as well as motor and vocal tics. This editorial comments on the study by Wang et al, which showed that cognitive-behavioral therapy (CBT) combined with habit reversal training significantly improved anxiety and tic severity in children with TS. We highlight the current status and future perspectives of behavioral interventions such as CBT, and comprehensive behavioral intervention for tics, demonstrating their efficacy in alleviating TS symptoms and improving patients' quality of life. Recognizing the multifaceted nature of TS, our discussion integrates empirical evidence from various studies to provide a comprehensive perspective on the role of behavioral therapy in the management of this complex condition. This editorial concludes by emphasizing the need for innovative strategies that may address the limitations of existing treatments and advocates a multidisciplinary approach that combines behavioral, pharmacological, and neurobiological interventions to improve outcomes for patients with TS.

Maternal autoimmune diseases and the risk of tics and Tourette's disorder in offspring: insights from Taiwan's real-world data

Background

Currently, tics and Tourette's disorder are burdensome neurological disorders that manifest in vocal and motor tics with onset during childhood. Previous studies have demonstrated that maternal autoimmune diseases may cause several neurodevelopmental disorders in offspring via maternal immune activation. However, the association between them has never been thoroughly researched. Thus, in this study, we aimed to explore whether maternal autoimmune diseases are associated with the risk of tics and Tourette's disorder in offspring in a real-world nationwide population-based cohort study.

Methods

We analyzed offspring with or without autoimmune disease exposure between 2009 and 2016 from national population databases in Taiwan. Multivariate analysis, multiple Cox regression analyses, and stratified analyses were conducted in the study.

Results

In total, 76,411 offspring with autoimmune disease exposure and 1,211,936 offspring without maternal autoimmune disease exposure were selected and analyzed in this study. The incidence of childhood tics and Tourette's disorder was 2.35 [95% confidence interval (CI) 2.23-4.86] and 1.89 (95% CI 1.86-1.92) per 10,000 person-months in children exposed to maternal autoimmune disease and non-exposed children, respectively. The children whose mothers had an autoimmune disease had a 1.26-fold risk of tics and Tourette's disorder compared to children whose mothers did not have an autoimmune disease [crude hazard ratio: 1.26; 95% CI, 1.20-1.34, adjusted hazard ratio (aHR): 1.22; 95% CI, 1.15-1.29]. Offspring of mothers with rheumatoid arthritis (aHR: 1.46, 95% CI, 1.07-1.97), system lupus erythematosus (aHR: 1.57, 95% CI, 1.18-2.09), Sjogren's syndrome (aHR: 1.28, 95% CI, 1.09-1.50), ankylosing spondylitis (aHR: 1.49, 95% CI, 1.07-2.09), Graves' disease (aHR: 1.26, 95% CI, 1.15-1.37), Hashimoto's thyroiditis (aHR: 1.59, 95% CI, 1.29-1.98), and type I diabetes (aHR: 1.68, 95% CI, 1.13-2.50) had a significantly higher risk of developing tics and Tourette's disorder. Aside from maternal autoimmune diseases, mothers with urinary tract infections, diabetes mellitus, hyperlipidemia, anemia, a sleep disorder, endometriosis, and depression were also associated with childhood tics and Tourette's disorder.

Conclusion

Maternal autoimmune diseases appeared to be associated with tics and Tourette's disorder in offspring, especially in mothers with the abovementioned diseases. Further research is warranted to investigate the possible pathogenetic mechanisms of these associations.

Brain Iron Alteration in Pediatric Tourette Syndrome: A Quantitative Susceptibility Mapping Study

BACKGROUND

The cortico-striato-thalamo-cortical circuits play a crucial role in the pathogenesis of Tourette syndrome (TS). While iron deficiency has been reported in adult TS, the iron content in pediatric TS remains poorly understood. This study aims to quantitatively assess whole-brain iron deposition in pediatric TS compared to typically developing (TD) children using quantitative susceptibility mapping (QSM).

METHODS

In this prospective study, we recruited 50 children with a clinical diagnosis of TS and 50 age- and gender-matched TD controls. Whole-brain images were acquired using 3D T1 and multi-echo gradient-recalled echo sequences. QSM maps were generated using the STISuite toolbox. After normalizing the QSM maps to Montreal Neurological Institute space, voxel-based analysis was applied to compare between-group differences in iron content. Additionally, we evaluated the relationship between iron content and tic severity in TS children using the Pearson's correlation test.

RESULTS

Compared to TD children, those with TS exhibited iron deficiency in the right anterior cingulum (pFDR < 0.001). Conversely, increased QSM values were observed in the bilateral putamen of TS children (pFDR < 0.001). Notably, QSM values in the left putamen showed a significant negative correlation with tic severity (p = 0.044).

CONCLUSIONS

Our findings suggest that disturbed brain iron homeostasis in specific regions is associated with pediatric TS. These results reinforce the importance of the cortico-striato-thalamo-cortical circuits in TS pathogenesis and highlight the potential role of iron dysregulation. Furthermore, our study demonstrates that QSM could serve as a valuable auxiliary biomarker for diagnosing and potentially monitoring pediatric TS.

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.

Clinical Study of Limosilactobacillus reuteri for the Treatment of Children with Chronic Tic Disorders/Tourette Syndrome: A Mid-Term Efficacy Evaluation

INTRODUCTION

Gut microbiota plays an important role in tic disorders (TDs); however, clinical research on probiotics for chronic TDs treatment is lacking. We aimed to investigate the effectiveness of probiotics, hypothesizing that their clinical efficacy is comparable to that of clonidine in treating chronic TDs.

METHODS

Patients were randomly assigned to receive either Limosilactobacillus reuteri or clonidine transdermal patch treatment for 8 weeks while maintaining their existing treatment. The Yale Global Tic Severity Scale (YGTSS); Swanson, Nolan, and Pelham-IV Scale (SNAP-IV); and Child Behavior Check List (CBCL) scores were assessed before and after treatment.

RESULTS

We matched the patients in both groups for age, sex, age at onset, and tic type. A significant improvement in YGTSS scores was observed in both groups (p = 0.024). The improvement in attention deficits on the SNAP-IV scale was similar between the two groups, with no significant difference (p = 0.465). For hyperactivity disorder, after matching patients in both groups for age, sex, age at onset, tic type, and Children's Yale-Brown Obsessive Compulsive Scale (CY-BOCS) scores, a significant difference in improvement was observed between the groups (p = 0.010), with the probiotics group showing greater improvement (0.3 ± 0.58 vs. 0.1 ± 0.50). At 9 weeks, social ability on the CBCL scale increased by 3.2 ± 6.26 from baseline in the probiotics group and by 0.6 ± 4.07 in the clonidine group, with a significant difference between the two (p = 0.049). Although there was no significant difference in behavioral problems between the two groups (p = 0.347), the trend of improvement was more pronounced in the probiotics group than in the clonidine group (12.7 ± 25.86 vs. 8.4 ± 13.15).

CONCLUSION

The mid-term efficacy evaluation demonstrated that L. reuteri, when added to the treatment of children with chronic TDs, was more effective in improving tic symptoms than clonidine transdermal patch treatment. Additionally, it provided moderate improvement in hyperactivity symptoms.

TRIAL REGISTRATION

chictr.org.cn (registration numbers ChiCTR2200056708, ChiCTR2200056578).

Effects of acupuncture combined with bone-setting therapy to treat tourette syndrome: a three-arm randomized controlled trial

OBJECTIVE

To explore the efficacy and safety of acupuncture combined with atlantoaxial joint bone-setting therapy for the treatment of Tourette syndrome.

METHODS

We randomly divided 600 patients at a ratio of 1∶1∶1 into three groups: group A (acupuncture combined with atlantoaxial joint bone setting therapy group), group B (acupuncture group), and group C (tiapride group). After two months of treatment, the Yale global tic severity scale (YGTSS) score reduction, improvement in social function impairment, clinical efficacy, and long-term efficacy in the three groups were compared.

RESULTS

After treatment, in the analysis of YGTSS score reduction, social function impairment improvement, the clinical control rate, and long-term efficacy, the results were all Group A > Group B > Group C, with a statistically significant difference (P < 0.05). However, the total clinical efficacy of treatment in group A (94.9%) was not significantly different from that in group B (91.8%). Adverse reactions did not occur in groups A and B, and several adverse reactions occurred in 29% (n = 58) of the group C patients.

CONCLUSION

Compared with traditional drug therapy, acupuncture combined with atlantoaxial joint bone setting therapy has better clinical and long-term efficacy. This treatment strategy can improve the social function of children and prevent adverse reactions to drugs.

Automatic Identification of Facial Tics Using Selfie-Video

The intrinsic nature of tic disorders, characterized by symptom variability and fluctuation, poses challenges in clinical evaluations. Currently, tic assessments predominantly rely on subjective questionnaires administered periodically during clinical visits, thus lacking continuous quantitative evaluation. This study aims to establish an automatic objective measure of tic expression in natural behavioral settings. A custom-developed smartphone application was used to record selfie-videos of children and adolescents with tic disorders exhibiting facial motor tics. Facial landmarks were utilized to extract tic-related features from video segments labeled as either "tic" or "non-tic". These features were then passed through a tandem of custom deep neural networks to learn spatial and temporal properties for tic classification of these segments according to their labels. The model achieved a mean accuracy of 95% when trained on data across all subjects, and consistently exceeded 90% accuracy in leave-one-session-out and leave-one-subject-out cross validation training schemes. This automatic tic identification measure may provide a valuable tool for clinicians in facilitating diagnosis, patient follow-up, and treatment efficacy evaluation. Combining this measure with standard smartphone technology has the potential to revolutionize large-scale clinical studies, thereby expediting the development and testing of novel interventions.

Advances in Clustering and Classification of Tic Disorders: A Systematic Review

Purpose

Tic disorders (TD) are common neurodevelopmental disorders characterized by heterogeneous tic symptoms in children, making diagnostic classification difficult. This complexity requires accurate subtyping using data-driven computational methods to identify patterns within clinical data. This systematic review primarily summarizes the current evidence for the classification of TD using a data-driven approach.

Patients and Methods

We conducted a systematic literature search on PubMed and Web of Science up to December 2023 and identified 16 publications analyzing 14 unique samples, totaling approximately 6000 subjects.

Results

Nine studies classified different subtypes of TD based on symptoms and behavior. Seven studies identified novel factor structures based on TD and its complex comorbidity patterns. Seven studies highlighted associations between TD symptom patterns and genetics, reflecting the diversity of underlying genetic mechanisms underlying TD.

Conclusion

This systematic review reveals significant variability in research on the classification of TD, which limits the application of findings for accurate diagnosis and guiding treatment strategies in pediatric psychiatry. Further research incorporating multidimensional information (such as genetic, neuroimaging, and environmental and social factors) is essential to improve the understanding of TD subtypes.

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.

Child Neurology: Simple Motor Tics Associated With Thalamic Ganglioglioma

Tic disorders (TDs) include a heterogeneous group of neurodevelopmental conditions linked to dysfunction of the cortical-striatal-thalamic-cortical (CSTC) circuit. In this article, we report a case of a 9-year-old boy who presented with infrequent tics affecting the right eye and mouth. Brain imaging revealed a T2-weighted hyperintense mass in the left thalamus. His tic symptoms resolved completely after lesionectomy. Neuropathology analysis showed dysplastic neurons, reactive gliosis, microvascular hyperplasia, and chronic inflammatory cell infiltration suggestive of ganglioglioma. Review of the literature identified 6 cases linking TDs to brain tumors, all of which involved multiple components of the CSTC circuit. TDs in these cases manifested as a combination of multiple motor and vocal tics, often with comorbidities such as obsessive-compulsive disorder and attention-deficit hyperactivity disorder. By contrast, our case presented solely with simple motor tics, which resolved after lesionectomy. The exclusive thalamic involvement in this case supports the critical role of the thalamus in the etiopathogenesis of TD. This case provides valuable insights into the structural basis of the clinical manifestations in patients with TD.

A critical role of action-related functional networks in Gilles de la Tourette syndrome

Gilles de la Tourette Syndrome (GTS) is a chronic tic disorder, characterized by unwanted motor actions and vocalizations. While brain stimulation techniques show promise in reducing tic severity, optimal target networks are not well-defined. Here, we leverage datasets from two independent deep brain stimulation (DBS) cohorts and a cohort of tic-inducing lesions to infer critical networks for treatment and occurrence of tics by mapping stimulation sites and lesions to a functional connectome derived from 1,000 healthy participants. We find that greater tic reduction is linked to higher connectivity of DBS sites (N = 37) with action-related functional resting-state networks, i.e., the cingulo-opercular (r = 0.62; p < 0.001) and somato-cognitive action networks (r = 0.47; p = 0.002). Regions of the cingulo-opercular network best match the optimal connectivity profiles of thalamic DBS. We replicate the significance of targeting cingulo-opercular and somato-cognitive action network connectivity in an independent DBS cohort (N = 10). Finally, we demonstrate that tic-inducing brain lesions (N = 22) exhibit similar connectivity to these networks. Collectively, these results suggest a critical role for these action-related networks in the pathophysiology and treatment of GTS.

[Advances in the application of comprehensive behavioral intervention in tic disorder]

Tic disorder is a neurodevelopmental disorder that occurs in children or adolescents, often attracting the attention of others due to involuntary, repetitive, and non-rhythmic tics, and drug therapy often causes negative emotions in children and their families due to its significant adverse reactions, poor compliance, and tendency of recurrence after drug withdrawal. In recent years, comprehensive behavioral intervention has shown great potential as a safe and effective treatment modality for tic disorders, with few adverse reactions. This article reviews the advances in the application of comprehensive behavioral intervention for tic disorder in China and abroad in the past 5 years, in order to provide a reference for clinical application.

Therapeutic Approach to Primary Tic Disorders and Associated Psychiatric Comorbidities

BACKGROUND/OBJECTIVES

The treatment of tics and psychiatric comorbidities is crucial when they affect the patient's well-being and relationships. However, the optimal pharmacological treatment (PT) tailored to each patient's phenotype remains unclear. The primary objective of this study is to describe the clinical characteristics and treatment received for tics and psychiatric comorbidities in our cohort of children and adult patients with tic disorders. Additionally, a further aim was to quantify the severity of tics, comorbidities and overall severity, and the overall clinical changes observed during the follow-up.

METHODS

Retrospective descriptive study of patients with tic disorders under follow-up at our Tic Functional Unit from January 2022 to March 2024. Two independent neurologists retrospectively applied the Clinical Global Impression of Change (CGI-C) and the Clinical Global Impression of Severity (CGI-S) scales at baseline and at last assessment.

RESULTS

A total of 36 individuals were included (63.8% males, median age = 18 years, IQR 19): 94.4% with Tourette syndrome (TS), 2.8% with chronic tic disorder (CTD), and 2.8% with provisional tic disorder (PTD). A total of 86% had at least one psychiatric comorbidity, the most common being obsessive-compulsive symptomatology (OCS) (52%), anxiety (52%), and attention deficit hyperactivity disorder (ADHD) (35%). At last assessment, 26 patients (72.2%) were on undergoing PT for tics and 3 were receiving additional botulinum toxin. The most used medication for tics were aripiprazole (46.2%) and clonazepam (46.2%), and for psychiatric comorbidities, SSRIs (42.9%), methylphenidate (19%), and benzodiazepines (57.1%). Overall improvement according to the CGI-C scale was mild (CGI-C 3). Children and adolescents showed greater improvement than adults (CGI-C 2 vs. 3; p = 0.005). Aripiprazole and clonazepam produced similar outcomes in reducing CGI-C.

CONCLUSIONS

We observed a favorable clinical course in patients treated with aripiprazole and clonazepam, which appear to be better than that obtained with other treatments. We consider that clonazepam may be useful as a first-line monotherapy and as an adjuvant for both tics and comorbidities in selected cases.

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.

TMS-evoked potentials provide novel neurophysiological features of Tourette syndrome

INTRODUCTION

Gilles de la Tourette syndrome (TS) is a neuropsychiatric disorder associated with abnormal activation of the cortico-striatal-thalamo-cortical circuits and dopaminergic system. We sought to examine changes in neurotransmission relating to cortical excitation/inhibition of TS by measuring TMS-evoked potentials (TEPs) of selected networks.

METHODS

Thirty-three adult TS patients and 18 healthy controls underwent evaluation of symptom severity using the YGTSS (tics), PUTS (premonitory urge), Y-BOCS (OCD), CAARS (ADHD), BDI (depression), and BAI (anxiety). TMS-EEG was performed to measure TEPs obtained from the primary motor cortex (M1), dorsolateral prefrontal cortex (DLPFC), and primary visual cortex (V1).

RESULTS

TEP analysis revealed a delayed P180 latency in M1 for TS patients compared to controls (p = 0.006). Lower early amplitude of TEP in response to stimulation of DLPFC (50-70 ms), and delayed DLPFC P180 latency were associated with higher tic severity (p = 0.001 and p = 0.003, respectively). M1 early amplitude (50-70 ms) also effectively differentiated TS with mild-moderate from severe tics (p = 0.003). Significant correlation was found between TEP V1 early amplitude (15-45 ms) and severity of TS anxiety.

CONCLUSION

Distinct TEP patterns registered in response to DLPFC, M1, and V1 stimulation may shed light on the underlying pathophysiology of TS and are associated with tic severity and comorbidities.

Association between human herpesviruses infections and childhood neurodevelopmental disorders: insights from two-sample mendelian randomization analyses and systematic review with meta-analysis

BACKGROUND

The potential roles of viral infections in neurodevelopmental disorders (NDDs) have been suggested based on previous studies. Given the high prevalence of human herpesviruses (HHVs), the associations between HHVs infection and the risk of NDDs warrant explored.

METHODS

Our study employs a two-sample Mendelian randomization (MR) analysis and systematic review with meta-analysis to investigate whether genetically predicted HHVs infection are linked to three main childhood NDDs-autism spectrum disorder (ASD), attention deficit hyperactivity disorder (ADHD), and Tourette syndrome (TS). We utilized genetic variants associated with HHV infections in genome-wide association study (GWAS) summary datasets of European populations to establish instrumental variables and statistics for three NDDs obtained from Psychiatric Genomics Consortium. MR analysis was performed using inverse-variance weighted, MR Egger, weighted median, simple median, weighted mode, and MR-PRESSO. In addition, publications associating HHVs infection with three NDDs were systematically searched using PubMed, Web of Science, and three Chinese databases for meta-analyses.

RESULTS

The MR results found no evidence to support a link between genetically predicted HHVs infection and the risk of NDDs based on existing datasets. Twenty-seven observational studies on children with HHVs infection and NDDs were considered eligible. Meta-analysis showed that cytomegalovirus and HHV-6 infection were related with ASD, while Epstein-Barr virus and cytomegalovirus infection were associated with TD in Chinese population.

CONCLUSIONS

These results contribute to a comprehensive understanding of the possibilities underlying HHV infections in affecting childhood NDDs. Further research is necessary to include larger and more robust statistics of HHV infections and NDDs.

TRIAL REGISTRATION

This systematic review was registered at PROSPERO as CRD42024554169. Retrospectively registered 26 July 2024.

Family functioning mediation in tic severity and quality of life for children with Tourette syndrome

BACKGROUND

Tourette syndrome (TS) is recognized as a neurodevelopmental disorder profoundly influenced by familial factors, particularly family functioning. However, the relationship among family functioning, tic severity, and quality of life in individuals with TS during childhood and adolescence remains unclear. We hypothesized that family functioning plays a role in the association between the severity of TS and quality of life in children.

AIM

To determine the role of family functioning in the relationship between TS severity and quality of life.

METHODS

This study enrolled 139 children (male/female = 113/26) with TS. We assessed tic severity using the Yale Global Tic Severity Scale, quality of life via the Tourette Syndrome Quality of Life Scale, and family functioning through the Family Assessment Device. Our analysis focused on correlating these measures and exploring the mediating role of family functioning in the relationship between tic severity and quality of life. Additionally, we examined if this mediating effect varied by gender or the presence of comorbidity.

RESULTS

We found that family communication dysfunction had a significant mediating effect between tic severity and both psychological symptoms (indirect effect: Β = 0.0038, 95% confidence interval: 0.0006-0.0082) as well as physical and activities of daily living impairment (indirect effect: Β = 0.0029, 95% confidence interval: 0.0004-0.0065). For vocal tic severity, this mediation was found to be even more pronounced. Additionally, in male participants and those without attention deficit hyperactivity disorder, the mediating effect of family communication dysfunction was still evident.

CONCLUSION

Our study highlights the impact of family functioning on the tic severity and the quality of life in children. This relationship is influenced by gender and comorbid conditions like attention deficit hyperactivity disorder.

Abnormal H3K4 enzyme catalytic activity and neuronal morphology caused by ASH1L mutations in individuals with Tourette syndrome

ASH1L potentially contributes to Tourette syndrome (TS) and other neuropsychiatric disorders, as our previous studies have shown. It regulates essential developmental genes by counteracting polycomb-mediated transcriptional repression, which restricts chromatin accessibility at target genes. ASH1L is highly expressed in the adult brain, playing a crucial role in the early stage. However, it remains unclear how ASH1L mutations carried by patients with TS participate in regulating neuronal growth processes leading to TS traits. Five TS families recruited in our study underwent comprehensive physical examinations and questionnaires to record clinical phenotypes and environmental impact factors. We validated the variants via Sanger sequencing and constructed two mutants near the catalytic domain of ASH1L. We conducted molecular modeling, in vitro assays, and primary neuron cultures to find the role of ASH1L in neuronal development and its correlation with TS. In this study, we validated five pathogenic ASH1L rare variants and observed symptoms in patients with simple tics and behavioral comorbidities. Mutations near the catalytic domain of TS patients cause mental state abnormalities and disrupt ASH1L function by destabilizing its spatial conformation, leading to decreased activity of catalytic H3K4, thereby affecting the neurite growth. We need to conduct larger-scale studies on TS patients and perform additional neurological evaluations on mature neurons. We first reported the effects of ASH1L mutations in TS patients, including phenotypic heterogeneity, protein function, and neurological growth. This information contributes to understanding the neurodevelopmental pathogenesis of TS in patients with ASH1L mutations.

Axial tics in Tourette syndrome and chronic tic disorders

BACKGROUND

Tics are the hallmark of Tourette syndrome (TS) and chronic tic disorders (CTD). Although typically involving the face, especially at onset, tics may involve any muscle under voluntary control, including axial muscles of the neck (causing head movements), shoulders and trunk (thorax and abdomen). We aimed to characterize these tics and provide a clinical frame for their associations and complications.

MATERIALS AND METHODS

We reviewed video recordings and clinical history of 196 patients with TS or CTD according to DSM-5.

RESULTS

Any axial tic was identified in 75% of patients. Tic distribution were head (n = 113, 57.6%), shoulder (n = 91, 46.4%), and trunk (n = 63, 32.2%). There were no differences in sex, age at onset or at evaluation between patients with and without axial tics. The most common axial tics by anatomical distribution were head turning, bilateral synchronous shoulder elevation and trunk jerks; however, tic phenomenology was quite variable. A greater severity of tics (P = 0.018) was associated with axial tics in the multivariate regression analysis. Head/neck tics associated with simple phonic tics (P = 0.002); whereas shoulder and trunk tics associated with complex motor tics (P < 0.05) in a bivariate analysis. Neck pain, breathing interference, sleep limitation and radiculopathy, secondary to axial tics were complications observed in a proportion of these cases.

CONCLUSIONS

Axial tics are commonly observed in patients with TS/CTD with variable phenomenology. They associate with greater tic severity, phonic tics and complex motor tics. They may result in neck pain, breathing interference, sleeping problems and cervical spine injuries.

The ZDHHC13/ZDHHC17 subfamily: From biological functions to therapeutic targets of diseases

The ZDHHC13/ZDHHC17 subfamily belongs to the zinc finger DHHC-domain containing (ZDHHC) family, including ZDHHC13 and ZDHHC17. Recent studies have shown that the ZDHHC13/ZDHHC17 subfamily is involved in various pathological and physiological processes, including S-palmitoylation, Mg2+ transport, and CALCOCO1-mediated Golgiphagy. Moreover, the ZDHHC13/ZDHHC17 subfamily plays a crucial role in the occurrence and development of many diseases, including Huntington disease (HD), osteoporosis, atopic dermatitis, diabetes, and cancer. In the present review, we describe the distribution, structure, and post-translational modifications (PTMs) of the ZDHHC13/ZDHHC17 subfamily. Moreover, we effectively summarize the biological functions and associated diseases of this subfamily. Given the pleiotropy of the ZDHHC13/ZDHHC17 subfamily, it is imperative to conduct further research on its members to comprehend the pertinent pathophysiological mechanisms and to devise tactics for managing and controlling various diseases.

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.

An update on the pharmacological management of Tourette syndrome and emerging treatment paradigms

INTRODUCTION

Tourette syndrome (TS) is a childhood-onset neurobehavioral disorder characterized by tics. Pharmacotherapy is advised for patients whose symptoms affect their quality of life.

AREAS COVERED

The authors review the tic phenomenology and TS diagnostic criteria. The bulk of this article focuses on pharmacotherapeutic options for treating tics. They also highlight pharmacotherapies in the research pipeline.

EXPERT OPINION

Tic treatment must be tailored to individual needs. Behavioral therapy is the first line of treatment. Most with bothersome tics need pharmacotherapy and rarely, for medication-refractory cases, surgical therapy is indicated. Alpha-2 agonists are considered in patients with mild tics, especially in those with attention deficit with or without hyperactivity. Second-generation antipsychotics like aripiprazole and tiapride may be considered for severe tics. However, prescribers should be mindful of potential side effects, especially drug-induced movement disorders. Botulinum toxin injections may be considered for focal motor tics. Topiramate can be considered when other treatments are ineffective, and its benefits outweigh the risks. The same holds true for vesicular monoamine transporter-2 inhibitors, as they are deemed to be safe and effective in real-world use and open-label trials despite not meeting primary endpoints in placebo-controlled trials. Cannabinoids may be considered in adults if the approaches above do not control tics.

Role of Neurosurgical Interventions in the Treatment of Movement Disorders Like Parkinson's Disease, Dystonia, and Tourette Syndrome

This article provides an overview of neurosurgical therapies for movement disorders (MDs), including Tourette syndrome, dystonia, Parkinson's disease (PD), and others. It focuses on the benefits of these treatments and suggests directions for further research. A total of 10 years' worth of English-language PubMed articles were combed through, with an emphasis on studies conducted in North America. To manage MDs like Parkinson's disease and Tourette syndrome, the results suggest that non-invasive neuromodulation techniques, closed-loop deep brain stimulation (DBS), and other advanced therapies may become the treatment of choice in the future. Research on dystonia is being focused on improving treatment methods by investigating new areas of the brain that might be stimulated through neurosurgery and looking at gene therapy. Modern technological developments, such as non-invasive neuromodulation procedures and improved imaging, provide promising substitutes for traditional surgical approaches. This study highlights the need for continuous clinical trials for better outcomes, which is why research and development in this area must continue.

Efficacy and Safety of Acupuncture for Tourette Syndrome in Children: A Meta-Analysis and Systematic Review

Despite the widespread use of acupuncture, its effectiveness and safety in treating Tourette syndrome (TS) remain controversial. Our research seeks to further evaluate the safety and effectiveness of acupuncture as a replacement therapy approach for children with TS. We conducted a comprehensive search for studies published from their inception to October 2023. The statistical analysis and subgroup analysis were conducted by software. Conduct a meta-analysis on the extracted data using the appropriate effect models. The meta-analysis was conducted on 26 studies consisting 1862 pediatric patients, which were selected from 976 identified articles. Acupuncture group demonstrated a significantly lower risk with a risk ratio (RR) of 0.29 (95% confidence interval [CI] = 0.19, 0.44, P < .0001), with only 5% of participants experiencing adverse reactions. Acupuncture treatment resulted in an 18% improvement in total effectiveness rates (RR = 1.18, 95% CI = [1.12, 1.25], P < .00001). The pooled data demonstrated that acupuncture therapy had a significant advantage in reducing the total score with the weighted mean difference (WMD) -4.92 (95% CI = [-6.38, -3.45], P < .00001) of the Yale Global Tic Severity Scale (YGTSS), the motor tic scores (WMD = -2.24, 95% CI = [-3.14, -1.35], P < .00001), the vocal tic scores (WMD: -2.34, 95% CI = [-3.31, -1.37], P < .00001), and the Traditional Chinese Medicine Syndrome Scores (TCMSS) (WMD: -2.47, 95% CI = [-2.87, -2.07], P < .0001). This meta-analysis reveals that acupuncture is more effective than most existing treatments in mitigating the symptoms of motor and vocal tics in children with TS, while also reducing the incidence of adverse reactions.

Network analysis of Tourette syndrome and attention-deficit/hyperactivity disorder symptoms in children and adolescents

BACKGROUND

While Tourette syndrome (TS) and attention-deficit/hyperactivity disorder (ADHD) often co-occur, the nature of the relationship between their symptoms is not well understood. Network analysis of psychopathology allow for detailed examinations of symptom interactions, providing an effective approach to explore the patterns of comorbidity between TS and ADHD symptoms.

METHODS

This study included 3,958 participants (male/female = 3,004/954, age mean ± SD = 8.60 ± 2.25 years). We collected data on TS symptoms using the Motor Tic, Obsessions and Compulsions, Vocal Tic Evaluation Survey (MOVES), and ADHD symptoms using the Swanson, Nolan, and Pelham Rating Scale-IV (SNAP-IV). Network analysis was employed to construct a combined network of TS and ADHD symptoms at the symptom level. We utilized the expected influence (EI) and bridge EI metrics to explore the core and bridge symptoms within the network.

RESULTS

The network structure demonstrated a moderate number of non-zero connections between TS and ADHD symptoms, constituting 23.06% of all potential connections. Core symptoms in the comorbidity network included "Often has difficulty sustaining attention in tasks or play activities," "Certain bad words or thoughts keep going through my mind," and "Words come out that I can't stop or control." Bridging symptoms identified were "Words come out that I can't stop or control," "I do certain things like jumping or clapping over and over," "I can't control all my movements," and "Often talks excessively."

CONCLUSION

The core and bridging symptoms identified in this study serve as potential therapeutic targets for the treatment of TS and ADHD comorbidity in clinical children and adolescents.

A Critical Examination of the Clinical Diagnosis of Functional Tic-like Behaviors

BACKGROUND

Since the COVID-19 pandemic, movement disorder clinics have seen an increase in patients with an unusual type of tic-like symptoms: young adults with abrupt onset complex behaviors. It was quickly suspected that these patients suffered from functional neurological symptoms, later named Functional Tic-Like Behaviors (FTLB). Subsequent research on the differential diagnosis between FTLB and tics has been substantial and led to the development of diagnostic checklists.

OBJECTIVES

We conducted a theoretical reappraisal of the FTLB literature to clarify the validity of the concept and its diagnostic implications.

METHODS

This paper addresses several key aspects of the current FTLB literature: circular reasoning, the complications of the FTLB phenomenology and demographics, the impact of FTLB on tic literature at large, and issues with alignment of the FTLB concept with the diagnostic criteria for functional disorders.

RESULTS

The clinical approach to FTLB might involve circular reasoning due to a lack of clinical benchmarks. The FTLB phenomenology and demographics may need more work to ensure a lack of bias and a proper description of this patient group including a clear distinction from tics. The impact of the FTLB discussion on the wider literature needs consideration. The validation of positive signs may help with both these endeavors and pave way to the inclusion of FTLB within psychiatric classification systems. Furthermore, the coexistence of FTLB and tics within the same patient needs to be addressed.

CONCLUSION

More research may be needed to fully establish the diagnosis of FTLB and differentiate it from tics.

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.

When the interoceptive and conceptual clash: The case of oppositional phenomenal self-modelling in Tourette syndrome

Tourette syndrome (TS) has been associated with a rich set of symptoms that are said to be uncomfortable, unwilled, and effortful to manage. Furthermore, tics, the canonical characteristic of TS, are multifaceted, and their onset and maintenance is complex. A formal account that integrates these features of TS symptomatology within a plausible theoretical framework is currently absent from the field. In this paper, we assess the explanatory power of hierarchical generative modelling in accounting for TS symptomatology from the perspective of active inference. We propose a fourfold analysis of sensory, motor, and cognitive phenomena associated with TS. In Section 1, we characterise tics as a form of action aimed at sensory attenuation. In Section 2, we introduce the notion of epistemic ticcing and describe such behaviour as the search for evidence that there is an agent (i.e., self) at the heart of the generative hierarchy. In Section 3, we characterise both epistemic (sensation-free) and nonepistemic (sensational) tics as habitual behaviour. Finally, in Section 4, we propose that ticcing behaviour involves an inevitable conflict between distinguishable aspects of selfhood; namely, between the minimal phenomenal sense of self-which is putatively underwritten by interoceptive inference-and the explicit preferences that constitute the individual's conceptual sense of self. In sum, we aim to provide an empirically informed analysis of TS symptomatology under active inference, revealing a continuity between covert and overt features of the condition.

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.

A Novel PDE10A Inhibitor for Tourette Syndrome and Other Movement Disorders

BACKGROUND

Tourette syndrome is a neurodevelopmental movement disorder involving basal ganglia dysfunction. PDE10A inhibitors modulate signaling in the striatal basal ganglia nuclei and are thus of interest as potential therapeutics in treating Tourette syndrome and other movement disorders.

METHODS

The preclinical pharmacology and toxicology, human safety and tolerability, and human PET striatal enzyme occupancy data for the PDE10A inhibitor EM-221 are presented.

RESULTS

EM-221 inhibited PDE10A with an in vitro IC50 of 9 pM and was >100,000 selective vs. other PDEs and other CNS receptors and enzymes. In rats, at doses of 0.05-0.50 mg/kg, EM-221 reduced hyperlocomotion and the disruption of prepulse inhibition induced by MK-801, attenuated conditioned avoidance, and facilitated novel object recognition, consistent with PDE10A's inhibition. EM-221 displayed no genotoxicity and was well tolerated up to 300 mg/kg in rats and 100 mg/kg in dogs. In single- and multiple-day ascending dose studies in healthy human volunteers, EM-221 was well tolerated up to 10 mg, with a maximum tolerated dose of 15 mg. PET imaging indicated that a PDE10A enzyme occupancy of up to 92.8% was achieved with a ~24 h half-life.

CONCLUSIONS

The preclinical and clinical data presented here support the study of EM-221 in phase 2 trials of Tourette syndrome and other movement disorders.

White matter alterations predict outcomes of comprehensive behavioral intervention for tics in children with Tourette syndrome: A diffusion MRI study

AIM

Tourette syndrome (TS) is a neurodevelopmental disorder that cause sudden uncontrolled rapid and repeated vocal sounds or movements called tics. Herein, diffusion magnetic resonance imaging (dMRI) connectometry was implemented to evaluate the white matter connectivity differences among TS patients.

METHODS

A total of 63 TS and 77 typically developed (TD) individuals were enrolled in the present study. dMRI connectometry was utilized to identify differences in connectivity patterns of white matter tracts in TS patients based on quantitative anisotropy (QA). QA was compared between TS and TD patients and correlated with severity scores such as Yale Global Tic Severity Scale (YGTSS) and Premonitory Urge for Tics Scale (PUTS).

RESULTS

Higher white matter connectivity of corpus callosum and bilateral cingulum as well as lower connectivity of corticothalamic and corticostriatal pathways were evident in TS relative to TD. The baseline YGTSS motor, YGTSS total, and PUTS were negatively correlated with corticostriatal pathway, corticothalamic pathway, and bilateral cingulum integrity, respectively. The changes in tic severity scores were also positively correlated with alterations in the white matter integrity of these brain regions following behavioral therapy.

CONCLUSION

Patients with TS have several abnormalities in their white matter microstructure particularly in the cortico-striato-thalamo-cortical (CSTC) circuit, correlated with the severity of the disease. Besides, the post-behavioral therapy changes in the white matter integrity of these regions are demonstrated as response predictors.

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.

Adenylyl cyclase 2 expression and function in neurological diseases

Adenylyl cyclases (Adcys) catalyze the formation of cAMP, a secondary messenger essential for cell survival and neurotransmission pathways in the CNS. Adcy2, one of ten Adcy isoforms, is highly expressed in the CNS. Abnormal Adcy2 expression and mutations have been reported in various neurological disorders in both rodents and humans. However, due to the lack of genetic tools, loss-of-function studies of Adcy2 are scarce. In this review, we summarize recent findings on Adcy2 expression and function in neurological diseases. Specifically, we first introduce the biochemistry, structure, and function of Adcy2 briefly. Next, the expression and association of Adcy2 in human patients and rodent models of neurodegenerative diseases (Alzheimer's disease and Parkinson's disease), psychiatric disorders (Tourette syndrome, schizophrenia, and bipolar disorder), and other neurological conditions (stress-associated disorders, stroke, epilepsy, and Lesch-Nyhan Syndrome) are elaborated. Furthermore, we discuss the pros and cons of current studies as well as key questions that need to be answered in the future. We hope to provide a focused review on Adcy2 that promotes future research in the field.

The effects of Shaoma Zhijing granules and its main components on Tourette syndrome

BACKGROUND

Tourette syndrome (TS) represents a neurodevelopmental disorder characterized by an uncertain etiology and influencing factors. Frequently, it co-occurs with conditions such as attention deficit hyperactivity disorder, obsessive-compulsive disorder, and sleep disturbances, which have garnered substantial attention from the research community in recent years. Clinical trials have demonstrated that Shaoma Zhijing Granules (SMZJG, 5-ling granule, also known as TSupport or T92 under U.S. development), a traditional Chinese medicine compound, is an effective treatment for TS.

PURPOSE

To conduct scientometric analysis on developing trends, research countries and institutions, current status, hot spots of TS and discuss the underlying mechanisms of SMZJG and its main components on TS. The aim is to provide valuable reference for ongoing clinical and basic research on TS and SMZJG.

STUDY DESIGN & METHODS

Using Tourette syndrome, SMZJG and its main components along with their synonyms as keywords, we conducted a comprehensive search across major scientific databases including the Web of Science Core Collection, PubMed and China National Knowledge Infrastructure (CNKI) databases. A total of 5952 references and 99 patents were obtained. Among these, 5039 articles and reviews, as well as 54 patents were analyzed by Citespace and VOSviewer software.

RESULTS

The available evidence indicates that the SMZJG's components likely exert their mechanisms in treating TS by regulating the dopaminergic pathway system, neurotransmitter imbalances, reducing neuroinflammation, promoting the repair of nerve damage and improving sleep disorders.

CONCLUSION

This comprehensive analysis lays the foundation for an extensive exploration of the feasibility and clinical applications of SMZJG in TS treatment.

Neurodevelopmental Disorders Associated with Gut Microbiome Dysbiosis in Children

The formation of the human gut microbiome initiates in utero, and its maturation is established during the first 2-3 years of life. Numerous factors alter the composition of the gut microbiome and its functions, including mode of delivery, early onset of breastfeeding, exposure to antibiotics and chemicals, and maternal stress, among others. The gut microbiome-brain axis refers to the interconnection of biological networks that allow bidirectional communication between the gut microbiome and the brain, involving the nervous, endocrine, and immune systems. Evidence suggests that the gut microbiome and its metabolic byproducts are actively implicated in the regulation of the early brain development. Any disturbance during this stage may adversely affect brain functions, resulting in a variety of neurodevelopmental disorders (NDDs). In the present study, we reviewed recent evidence regarding the impact of the gut microbiome on early brain development, alongside its correlation with significant NDDs, such as autism spectrum disorder, attention-deficit/hyperactivity disorder, Tourette syndrome, cerebral palsy, fetal alcohol spectrum disorders, and genetic NDDs (Rett, Down, Angelman, and Turner syndromes). Understanding changes in the gut microbiome in NDDs may provide new chances for their treatment in the future.

Psychometric Properties of the MOVES Scale for Tourette Syndrome and Comorbidities in a Chinese Cultural Context

The Motor tic, Obsessions and Compulsions, Vocal tic Evaluation Survey (MOVES) is a widely used screening tool for Tourette syndrome (TS) and associated comorbidities. This study evaluated its applicability for children in China using 7,125 participants from the National Center for Children's Health (Beijing). Psychometric evaluations included exploratory and confirmatory factor analysis, yielding a 16-item, four-factor model that explained 55.11% of the variance and demonstrated good internal consistency (Cronbach's alpha = 0.88) and test-retest reliability (ICC = 0.86). The scale showed strong convergent, discriminant, and criterion-related validity and was significantly correlated with other established TS scales. The results affirm the reliability and validity of the MOVES for screening TS in Asian contexts, addressing a crucial gap in the region's TS assessment tools.

Deep Brain Stimulation of the Medial Forebrain Bundle for Treatment-Resistant Depression: A Systematic Review Focused on the Long-Term Antidepressive Effect

OBJECTIVE

Major depression affects millions of people worldwide and has important social and economic consequences. Since up to 30% of patients do not respond to several lines of antidepressive drugs, deep brain stimulation (DBS) has been evaluated for the management of treatment-resistant depression (TRD). The superolateral branch of the medial forebrain bundle (slMFB) appears as a "hypothesis-driven target" because of its role in the reward-seeking system, which is dysfunctional in depression. Although initial results of slMFB-DBS from open-label studies were promising and characterized by a rapid clinical response, long-term outcomes of neurostimulation for TRD deserve particular attention. Therefore, we performed a systematic review focused on the long-term outcome of slMFB-DBS.

MATERIALS AND METHODS

A literature search using Preferred Reporting Items for Systematic Reviews and Meta-Analyses criteria was conducted to identify all studies reporting changes in depression scores after one-year follow-up and beyond. Patient, disease, surgical, and outcome data were extracted for statistical analysis. The Montgomery-Åsberg Depression Rating Scale (ΔMADRS) was used as the clinical outcome, defined as percentage reduction from baseline to follow-up evaluation. Responders' and remitters' rates were also calculated.

RESULTS

From 56 studies screened for review, six studies comprising 34 patients met the inclusion criteria and were analyzed. After one year of active stimulation, ΔMADRS was 60.7% ± 4%; responders' and remitters' rates were 83.8% and 61.5%, respectively. At the last follow-up, four to five years after the implantation, ΔMADRS reached 74.7% ± 4.6%. The most common side effects were stimulation related and reversible with parameter adjustments.

CONCLUSIONS

slMFB-DBS appears to have a strong antidepressive effect that increases over the years. Nevertheless, to date, the overall number of patients receiving implantations is limited, and the slMFB-DBS surgical technique seems to have an important impact on the clinical outcome. Further multicentric studies in a larger population are needed to confirm slMFB-DBS clinical outcomes.

Aberrant Functional Connectivity of the Salience Network in Adult Patients with Tic Disorders: A Resting-State fMRI Study

Tic disorders (TD) are characterized by the presence of motor and/or vocal tics. Common neurophysiological frameworks suggest dysregulations of the cortico-striatal-thalamo-cortical (CSTC) brain circuit that controls movement execution. Besides common tics, there are other "non-tic" symptoms that are primarily related to sensory perception, sensorimotor integration, attention, and social cognition. The existence of these symptoms, the sensory tic triggers, and the modifying effect of attention and cognitive control mechanisms on tics may indicate the salience network's (SN) involvement in the neurophysiology of TD. Resting-state functional MRI measurements were performed in 26 participants with TD and 25 healthy controls (HC). The group differences in resting-state functional connectivity patterns were measured based on seed-to-voxel connectivity analyses. Compared to HC, patients with TD exhibited altered connectivity between the core regions of the SN (insula, anterior cingulate cortex, and temporoparietal junction) and sensory, associative, and motor-related cortices. Furthermore, connectivity changes were observed in relation to the severity of tics in the TD group. The SN, particularly the insula, is likely to be an important site of dysregulation in TD. Our results provide evidence for large-scale neural deviations in TD beyond the CSTC pathologies. These findings may be relevant for developing treatment targets.

Impacts of ADHD Symptomatology on the Response to Cognitive-Behavioural Therapy with Gilles de la Tourette Syndrome Patients

(1) Background: Gilles de la Tourette Syndrome (TS) is a neurodevelopmental disorder characterized by motor and vocal tics. Attention deficit and hyperactivity disorder (ADHD) is a common comorbidity of TS that adds further impairment. Cognitive-behavioural therapy (CBT) has shown efficacy in treating tics, yet its effectiveness in individuals with TS and comorbid ADHD remains unclear. Also, it is suggested that ADHD characteristics like executive dysfunction and inattention could hinder the response to CBT. This study aims to compare the response to CBT for tics and its maintenance six months post-therapy among TS individuals with and without ADHD symptoms. (2) Methods: In this study, 55 TS participants who completed 14-week CBT for tics were split into high (TS+) or low (TS-) ADHD symptomatology groups. Outcomes were evaluated using the Yale Global Tic Severity Scale (YGTSS) regarding global tic severity and motor and vocal tic frequency post-CBT and at a 6-month follow-up. (3) Results: No significant group difference was found regarding improvements post-CBT (n = 55), nor the maintenance six months later (n = 45). (4) Conclusions: ADHD symptoms may not hinder the response to CBT or its maintenance, suggesting that TS individuals with ADHD symptoms may not require specialized CBT interventions.

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.

Tics emergencies and malignant tourette syndrome: Assessment and management

Tourette syndrome (TS) is a complex neurodevelopmental disorder characterized by the presence of tics, frequently accompanied by a variety of neuropsychiatric comorbidities. A subset of patients with TS present with severe and disabling symptoms, requiring prompt therapeutic intervention. Some of these manifestations may result in medical emergencies when severe motor or phonic tics lead to damage of anatomical structures closely related to the tic. Examples include myelopathy or radiculopathy following severe neck ("whiplash") jerks or a variety of self-inflicted injuries. In addition to self-aggression or, less commonly, allo-aggression, some patients exhibit highly inappropriate behavior, suicidal tendencies, and rage attacks which increase the burden of the disease and are important components of "malignant TS". This subset of TS is frequently associated with comorbid obsessive-compulsive disorder. Therapeutic measures include intensive behavioral therapy, optimization of oral pharmacotherapy, botulinum toxin injections, and deep brain stimulation.

Responsive deep brain stimulation for the treatment of Tourette syndrome

To report the results of 'responsive' deep brain stimulation (DBS) for Tourette syndrome (TS) in a National Institutes of Health funded experimental cohort. The use of 'brain derived physiology' as a method to trigger DBS devices to deliver trains of electrical stimulation is a proposed approach to address the paroxysmal motor and vocal tic symptoms which appear as part of TS. Ten subjects underwent bilateral staged DBS surgery and each was implanted with bilateral centromedian thalamic (CM) region DBS leads and bilateral M1 region cortical strips. A series of identical experiments and data collections were conducted on three groups of consecutively recruited subjects. Group 1 (n = 2) underwent acute responsive DBS using deep and superficial leads. Group 2 (n = 4) underwent chronic responsive DBS using deep and superficial leads. Group 3 (n = 4) underwent responsive DBS using only the deep leads. The primary outcome measure for each of the 8 subjects with chronic responsive DBS was calculated as the pre-operative baseline Yale Global Tic Severity Scale (YGTSS) motor subscore compared to the 6 month embedded responsive DBS setting. A responder for the study was defined as any subject manifesting a ≥ 30 points improvement on the YGTSS motor subscale. The videotaped Modified Rush Tic Rating Scale (MRVTRS) was a secondary outcome. Outcomes were collected at 6 months across three different device states: no stimulation, conventional open-loop stimulation, and embedded responsive stimulation. The experience programming each of the groups and the methods applied for programming were captured. There were 10 medication refractory TS subjects enrolled in the study (5 male and 5 female) and 4/8 (50%) in the chronic responsive eligible cohort met the primary outcome manifesting a reduction of the YGTSS motor scale of ≥ 30% when on responsive DBS settings. Proof of concept for the use of responsive stimulation was observed in all three groups (acute responsive, cortically triggered and deep DBS leads only). The responsive approach was safe and well tolerated. TS power spectral changes associated with tics occurred consistently in the low frequency 2-10 Hz delta-theta-low alpha oscillation range. The study highlighted the variety of programming strategies which were employed to achieve responsive DBS and those used to overcome stimulation induced artifacts. Proof of concept was also established for a single DBS lead triggering bi-hemispheric delivery of therapeutic stimulation. Responsive DBS was applied to treat TS related motor and vocal tics through the application of three different experimental paradigms. The approach was safe and effective in a subset of individuals. The use of different devices in this study was not aimed at making between device comparisons, but rather, the study was adapted to the current state of the art in technology. Overall, four of the chronic responsive eligible subjects met the primary outcome variable for clinical effectiveness. Cortical physiology was used to trigger responsive DBS when therapy was limited by stimulation induced artifacts.

Resting network architecture of theta oscillations reflects hyper-learning of sensorimotor information in Gilles de la Tourette syndrome

Gilles de la Tourette syndrome is a neurodevelopmental disorder characterized by motor and vocal tics. It is associated with enhanced processing of stimulus-response associations, including a higher propensity to learn probabilistic stimulus-response contingencies (i.e. statistical learning), the nature of which is still elusive. In this study, we investigated the hypothesis that resting-state theta network organization is a key for the understanding of superior statistical learning in these patients. We investigated the graph-theoretical network architecture of theta oscillations in adult patients with Gilles de la Tourette syndrome and healthy controls during a statistical learning task and in resting states both before and after learning. We found that patients with Gilles de la Tourette syndrome showed a higher statistical learning score than healthy controls, as well as a more optimal (small-world-like) theta network before the task. Thus, patients with Gilles de la Tourette syndrome had a superior facility to integrate and evaluate novel information as a trait-like characteristic. Additionally, the theta network architecture in Gilles de la Tourette syndrome adapted more to the statistical information during the task than in HC. We suggest that hyper-learning in patients with Gilles de la Tourette syndrome is likely a consequence of increased sensitivity to perceive and integrate sensorimotor information leveraged through theta oscillation-based resting-state dynamics. The study delineates the neural basis of a higher propensity in patients with Gilles de la Tourette syndrome to pick up statistical contingencies in their environment. Moreover, the study emphasizes pathophysiologically endowed abilities in patients with Gilles de la Tourette syndrome, which are often not taken into account in the perception of this common disorder but could play an important role in destigmatization.

Biomarkers and Tourette syndrome: a systematic review and meta-analysis

Objective

This research aims to investigate whether peripheral biomarkers might differentiate individuals with Tourette syndrome (TS) from those without the condition.

Methods

A broad range of databases was searched through November 2022. This study employed a systematic literature review and subsequent meta-analysis of case-control studies that assessed the aberration of biomarkers of patients with TS and controls.

Results

A total of 81 studies were identified, out of which 60 met the eligibility criteria for inclusion in the meta-analysis. Following a meticulous screening procedure to determine the feasibility of incorporating case-control studies into the meta-analysis, 13 comparisons were statistically significant [CD3+ T cell, CD4+ T cell, CD4+ T cell to CD8+ T cell ratio, NK-cell, anti-streptolysin O antibodies, anti-DNase antibodies, glutamic acid (Glu), aspartic acid (Asp), ferritin (Fe), zinc (Zn), lead (Pb), vitamin D, and brain-derived neurotrophic factor (BDNF)]. Publication bias was found for anti-streptolysin O antibodies. Suggestive associations were evidenced for norsalsolinol (NSAL), neuron-specific enolase (NSE), and S100B.

Conclusion

In this study, we present empirical evidence substantiating the link between several peripheral biomarkers and the early diagnosis of TS. Larger and more standardized studies are necessary to replicate the observed results, elucidate the specificity of the biomarkers for TS, and evaluate their precision for use in clinical settings.