A Review and Update on Tourette Syndrome: Where Is the Field Headed?

Concerning neuromodulation as treatment of neurological and neuropsychiatric disorder: Insights gained from selective targeting of the subthalamic nucleus, para-subthalamic nucleus and zona incerta in rodents

Neuromodulation such as deep brain stimulation (DBS) is advancing as a clinical intervention in several neurological and neuropsychiatric disorders, including Parkinson's disease, dystonia, tremor, and obsessive-compulsive disorder (OCD) for which DBS is already applied to alleviate severely afflicted individuals of symptoms. Tourette syndrome and drug addiction are two additional disorders for which DBS is in trial or proposed as treatment. However, some major remaining obstacles prevent this intervention from reaching its full therapeutic potential. Side-effects have been reported, and not all DBS-treated individuals are relieved of their symptoms. One major target area for DBS electrodes is the subthalamic nucleus (STN) which plays important roles in motor, affective and associative functions, with impact on for example movement, motivation, impulsivity, compulsivity, as well as both reward and aversion. The multifunctionality of the STN is complex. Decoding the anatomical-functional organization of the STN could enhance strategic targeting in human patients. The STN is located in close proximity to zona incerta (ZI) and the para-subthalamic nucleus (pSTN). Together, the STN, pSTN and ZI form a highly heterogeneous and clinically important brain area. Rodent-based experimental studies, including opto- and chemogenetics as well as viral-genetic tract tracings, provide unique insight into complex neuronal circuitries and their impact on behavior with high spatial and temporal precision. This research field has advanced tremendously over the past few years. Here, we provide an inclusive review of current literature in the pre-clinical research fields centered around STN, pSTN and ZI in laboratory mice and rats; the three highly heterogeneous and enigmatic structures brought together in the context of relevance for treatment strategies. Specific emphasis is placed on methods of manipulation and behavioral impact.

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.

Architecture of the subthalamic nucleus

The subthalamic nucleus (STN) is a major neuromodulation target for the alleviation of neurological and neuropsychiatric symptoms using deep brain stimulation (DBS). STN-DBS is today applied as treatment in Parkinson´s disease, dystonia, essential tremor, and obsessive-compulsive disorder (OCD). STN-DBS also shows promise as a treatment for refractory Tourette syndrome. However, the internal organization of the STN has remained elusive and challenges researchers and clinicians: How can this small brain structure engage in the multitude of functions that renders it a key hub for therapeutic intervention of a variety of brain disorders ranging from motor to affective to cognitive? Based on recent gene expression studies of the STN, a comprehensive view of the anatomical and cellular organization, including revelations of spatio-molecular heterogeneity, is now possible to outline. In this review, we focus attention to the neurobiological architecture of the STN with specific emphasis on molecular patterns discovered within this complex brain area. Studies from human, non-human primate, and rodent brains now reveal anatomically defined distribution of specific molecular markers. Together their spatial patterns indicate a heterogeneous molecular architecture within the STN. Considering the translational capacity of targeting the STN in severe brain disorders, the addition of molecular profiling of the STN will allow for advancement in precision of clinical STN-based interventions.

Efficacy and Safety of Acupuncture Combined with Herbal Medicine for Children and Adolescents with Tourette Syndrome: A Systematic Review and Meta-Analysis

BACKGROUND

With the increasing prevalence of Tourette syndrome (TS), the search for alternative therapy for TS is a growing public concern. In recent years, a growing number of randomized controlled trials (RCTs) have revealed the value of acupuncture combined with herbal medicine for the treatment of TS; however, its holistic efficacy and safety remains unclear. This study aimed to evaluate the efficacy and safety of acupuncture combined with herbal medicine and to provide preliminary evidence for clinical practice.

METHODS

Eight databases were searched from their establishment to November 27, 2022, to collect RCTs of acupuncture combined with herbal medicine for TS treatment. Two researchers independently completed the study screening, data extraction, and risk of bias assessment by using NoteExpress, Excel, and Cochrane Risk of Bias Tool 2.0 (RoB 2.0). Stata 15.0 software was applied to conduct meta-analysis.

RESULTS

A total of 1,400 participants in 18 RCTs were included. Compared with the Western medicine, acupuncture combined with herbal medicine had better curative effect in the field of effective rate (risk ratio [RR] = 1.18, 95% CI: [1.12, 1.23], p < 0.05, I2 = 0%), Yale Global Tic Severity Scale (YGTSS) total score (mean difference [MD] = -3.91, 95% CI: [-5.49, -2.33], p < 0.05, I2 = 96.4%), TCM syndrome total score (MD = -2.42, 95% CI: [-3.71, -1.13], p < 0.05, I2 = 87.1%), and serum IgE negative rate (RR = 3.41, 95% CI: [1.69, 6.87], p < 0.05, I2 = 0%). Furthermore, acupuncture combined with herbal medicine reduced the adverse reaction rate (RR = 0.20, 95% CI: [0.14, 0.30], p < 0.05, I2 = 0%) and the recurrence rate (RR = 0.27, 95% CI: [0.13, 0.52], p < 0.05, I2 = 0%).

CONCLUSION

This study demonstrated the efficacy and safety of acupuncture combined with herbal medicine, which is probably a better alternative therapy for TS. However, the small number, low quality, and potential bias of the included studies caused the limitations of our results. More high-quality RCTs are required to provide supplementary evidence in the future.

Hintergrund

Mit der steigenden Prävalenz des Tourette-Syndroms (TS) ist die Suche nach alternativen Therapien für TS zunehmend zu einer Angelegenheit von öffentlichem Interesse geworden. In den vergangenen Jahren zeigte eine immer größer werdende Zahl randomisierter, kontrollierter Studien den Nutzen der Akupunktur in Kombination mit Heilkräutern; ihre ganzheitliche Wirksamkeit und Sicherheit ist jedoch weiterhin nicht klar. Mit dieser Studie sollten die Wirksamkeit und Sicherheit von Akupunktur in Kombination mit Heilkräutern beurteilt und erste Belege für die klinische Praxis gewonnen werden.

Methoden

Acht (8) Datenbanken wurden ab ihrer Einrichtung bis zum 27. November 2022 nach randomisierten kontrollierten Studien (RCTs) über Akupunktur in Kombination mit Heilkräutern zur Behandlung von TS durchsucht. Das Screening der Studien, die Datenextraktion und die Bewertung des Verzerrungsrisikos wurden von zwei unabhängigen Forschern mit Hilfe von NoteExpress, Excel und dem Cochrane Risk of Bias Tool 2.0 (RoB 2.0) durchgeführt. Die Metaanalyse erfolgte mit der Software Stata 15.0.

Ergebnisse

Insgesamt wurden 1400 Teilnehmer in 18 RCTs eingeschlossen. Im Vergleich zur westlichen Medizin (WM) hatte Akupunktur in Kombination mit Heilkräutern eine bessere kurative Wirkung in Bezug auf die Wirksamkeitsrate (RR = 1,18, 95%-KI [1,12, 1,23], p < 0,05, I2 = 0%), den Gesamtscore der Yale Global Tic Severity Scale (YGTSS) (MD = -3,91, 95%-KI [-5,49, -2,33], p < 0,05, I2 = 96,4%), den TCM-Syndrom-Gesamtscore (MD = -2,42, 95%-KI [-3,71, -1,13], p < 0,05, I2 = 87,1%) und die Serum-IgE-Negativrate (RR = 3,41, 95%-KI [1,69, 6,87], p <0,05, I2 = 0 %). Darüber hinaus verringerte Akupunktur in Kombination mit Heilkräutern die Nebenwirkungsrate (RR = 0,20, 95%-KI [0,14, 0,30], p < 0,05, I2 = 0%) sowie die Rezidivrate (RR = 0,27, 95%-KI [0,13, 0,52], p < 0,05, I2 = 0%).

Schlussfolgerung

Diese Studie belegt die Wirksamkeit und Sicherheit der Akupunktur in Kombination mit Heilkräutern, die wahrscheinlich eine bessere alternative Therapie für TS darstellt. Unsere Ergebnisse werden allerdings durch die geringe Zahl, die niedrige Qualität und die potenzielle Verzerrung der eingeschlossenen Studien eingeschränkt. Zukünftig sind weitere hochwertige RCTs erforderlich, die zusätzliche Belege liefern.

Childhood Comorbidity Severity Impacts Adolescent Substance Consumption in Patients With Tourette Syndrome

BACKGROUND

This study explores the longitudinal impact of severity of Tourette Syndrome (TS), diagnosis and severity of Attention-Deficit/Hyperactivity Disorder (ADHD) and Obsessive-Compulsive Disorder (OCD), and guardian socioeconomic status on the level of substance use of pediatric patients with TS.

METHODS

A total of 314 pediatric patients with TS participated at time 1 (T1). During these visits, the severity of the patients' TS, ADHD, and OCD symptoms were assessed, along with their guardians' socioeconomic status. At time 2 (T2), between four and eight years later (median 5.6 years), 227 patients returned for a follow-up. Here, the patients answered questions about their intake of alcohol, cigarettes, and illegal substances. The relationship between the patients' diagnoses, symptom severity, and socioeconomic status at T1 and reported substance use at T2 was then analyzed using binary logistic regression.

RESULTS

Increased severity of ADHD and lower guardian socioeconomic status at T1 significantly increased the odds of later high cigarette consumption. Furthermore, both presence and increased severity of ADHD at T1 increased the odds of illegal substance consumption at T2. Conversely, increased severity of OCD at T1 significantly decreased cigarette and illegal substance consumption at T2, whereas both presence and increased severity of OCD decreased alcohol consumption.

CONCLUSIONS

Pediatric patients with TS with increased ADHD severity have increased risk of consuming illegal substances and high amounts of cigarettes as adolescents, whereas increased OCD severity may act as a protective factor. Having preventative conversations about substance consumption with patients with TS with high ADHD severity is important.

Integrated network pharmacology and experimental verification to explore the molecular mechanism of Jingxin Zhidong formula for treating Tic disorder

ETHNOPHARMACOLOGICAL RELEVANCE

As a traditional Chinese medicine formula, Jingxin Zhidong Formula (JXZDF) based on ancient amber powder has been prescribed to alleviate tic disorders (TD) according to our clinical practice for many years. However, the underlying molecular mechanisms remain largely unknown.

AIM OF STUDY

To explore the potential mechanism of JXZDF in the treatment of TD by using network pharmacology and experimental validation.

MATERIALS AND METHODS

The chemical components of JXZDF were detected and the potential pathway enrichment analyses were conducted based on network pharmacology. Finally, we performed cell viability assays and Western blotting on LPS-induced BV-2 cells, and subsequently performed behavioral tests and Western blotting in SD rats model for TD to explore the mechanism of JXZDF on TD.

RESULTS

By LC-ESI-MS/MS system and searching the databases, we identified 5 key compounds and 29 hub targets of JXZDF on TD. KEGG enrichment analysis showed that PI3K/AKT signaling pathway may be the key pathway for JXZDF on TD. The vitro experimental results proved that JXZDF can inhibit the phosphorylation of PI3K and AKT proteins on LPS-induced BV-2 cells. The animal experimental results indicated that JXZDF can effectively alleviate the stereotypic behavior and hyperactivity of the TD rats, and downregulated PI3K/AKT pathway to inhibit microglia activation in the hippocampus tissue.

CONCLUSION

This study indicated that JXZDF can change microglial activation and expression of proinflammatory mediators through the inactivation of PI3K/AKT signaling pathway, which may be one of the mechanisms of JXZDF in treating TD.

Comparison of efficacy of deep brain stimulation, repeat transcranial magnetic stimulation, and behavioral therapy in Tourette syndrome: A systematic review and Bayesian Network Meta-Analysis

Background

Tourette syndrome (TS) is an incurable neuropsychiatric disorder. Deep brain stimulation (DBS), repeat transcranial magnetic stimulation (rTMS), and behavioral therapy (BT) are all effective treatments. However, the comparison of therapeutic effect of these three therapies is lacking.

Methods

A systematic literature search was conducted for randomized controlled studies (RCT). A network meta-analysis by R4.04 software according to Bayesian framework were performed. Results were meta-analyzed and network meta-analyzed to evaluate and compare the efficacy of DBS, rTMS and BT in TS patients.

Results

A total of 18 randomized controlled studies with 661 participants were included. The Yale Global Tic Severity Scale (YGTSS) and the Yale-Brown Obsessive-Compulsive Scale (Y-BOCS) were utilized to evaluate the symptoms of TS. All three treatments improved the tic symptoms of TS [DBS 12.11 (95%CI 7.58-16.65); rTMS 4.96 (95%CI 1.01-10.93); andBT 11.72 (95%CI 10.42-13.01)]; and obsessive-compulsive symptom [DBS 4.9 (95%CI 1.13-8.67); rTMS 5.28 (95%CI 0.21-10.77); and BT 1.61 (95%CI 0.74-2.48)]. The cumulative probability results showed that DBS had the best effect on the improvement of tic symptoms, followed by BT; and rTMS was ranked last. However, in terms of improvement of obsessional symptoms, rTMS was ranked first, DBS was ranked second, and BT was ranked last. In addition, the meta regression analysis of YGTSS in DBS, rTMS and BT has significant difference (P = 0.05).

Limitation

Due to the lack of quantitative indicators, we did not perform a network meta-analysis of the side effects of the three treatments.

Conclusion

Our study showed that DBS, rTMS, and BT are effective in TS. DBS causes the best improvement in tic symptoms, and rTMS is the most effective in improving the obsessive-compulsive symptoms.

Stereotactic Surgery for Treating Intractable Tourette Syndrome: A Single-Center Pilot Study

To evaluate the potential effect of radiofrequency ablation and deep brain stimulation in patients with treatment-refractory Tourette syndrome (TS), this study enrolled thirteen patients with TS who were admitted to our hospital between August 2002 and September 2018. Four patients received a single- or multi-target radiofrequency ablation after local, potentiated, or general anesthesia; eight patients underwent deep brain stimulation (DBS) surgery; and one patient underwent both ablation and DBS surgery. The severity of tics and obsessive compulsive disorder symptoms and the quality of life were evaluated using the Yale Global Tic Severity Scale (YGTSS), Yale−Brown Obsessive Compulsive Scale (YBOCS), and Gilles de la Tourette Syndrome Quality of Life scale (GTS-QOL), respectively, before surgery, one month after surgery, and at the final follow-up after surgery, which was conducted in December 2018. A paired-sample t test and a multiple linear regression analysis were performed to analyze the data. All patients underwent the operation successfully without any severe complications. Overall, the YGTSS total scores at one month post-surgery (44.1 ± 22.3) and at the final visit (35.1 ± 23.7) were significantly decreased compared with those at baseline (75.1 ± 6.2; both p < 0.05). Additionally, the YBOCS scores at one month post-surgery (16.5 ± 10.1) and at the final visit (12.0 ± 9.5) were significantly decreased compared with those at baseline (22.5 ± 13.1; both p < 0.05). Furthermore, the GTS-QOL scores at one month post-surgery (44.0 ± 12.8) and at the final visit (31.0 ± 17.8) were significantly decreased compared with those at baseline (58.4 ± 14.2; both p < 0.05). Results from a multiple linear regression analysis revealed that the improvement in the YGTSS total score was independently associated with the improvement in the GTS-QOL score at one month post-surgery (standardized β = 0.716, p = 0.023) and at the final visit (standardized β = 1.064, p = 0.000). Conversely, changes in YBOCS scores did not correlate with changes in GTS-QOL scores (p > 0.05). Our results demonstrate that tics, psychiatric symptoms, and the quality of life in patients with intractable TS may be relieved by stereotactic ablation surgery and deep brain stimulation. Furthermore, it appears that the improvement in tics contributes more to the post-operative quality of life of patients than does the improvement in obsessive compulsive symptoms.

European clinical guidelines for Tourette syndrome and other tic disorders-version 2.0. Part III: pharmacological treatment

In 2011, the European Society for the Study of Tourette Syndrome (ESSTS) published the first European guidelines for Tourette Syndrome (TS). We now present an update of the part on pharmacological treatment, based on a review of new literature with special attention to other evidence-based guidelines, meta-analyses, and randomized double-blinded studies. Moreover, our revision took into consideration results of a recent survey on treatment preferences conducted among ESSTS experts. The first preference should be given to psychoeducation and to behavioral approaches, as it strengthens the patients' self-regulatory control and thus his/her autonomy. Because behavioral approaches are not effective, available, or feasible in all patients, in a substantial number of patients pharmacological treatment is indicated, alone or in combination with behavioral therapy. The largest amount of evidence supports the use of dopamine blocking agents, preferably aripiprazole because of a more favorable profile of adverse events than first- and second-generation antipsychotics. Other agents that can be considered include tiapride, risperidone, and especially in case of co-existing attention deficit hyperactivity disorder (ADHD), clonidine and guanfacine. This view is supported by the results of our survey on medication preference among members of ESSTS, in which aripiprazole was indicated as the drug of first choice both in children and adults. In treatment resistant cases, treatment with agents with either a limited evidence base or risk of extrapyramidal adverse effects might be considered, including pimozide, haloperidol, topiramate, cannabis-based agents, and botulinum toxin injections. Overall, treatment of TS should be individualized, and decisions based on the patient's needs and preferences, presence of co-existing conditions, latest scientific findings as well as on the physician's preferences, experience, and local regulatory requirements.

Tics, tremors and other movement disorders in childhood

Movement disorders presenting in childhood include tics, dystonia, chorea, tremor, stereotypy, myoclonus, and parkinsonism, each of which can be part of various clinical syndromes with distinct etiologies.  Some of these conditions are benign and require only reassurance; others are bothersome and require treatment, or may be clues that herald underlying pathology.  Answers lie in the inherent characteristics of the movements themselves, together with the clinical context provided in the history obtained by the examiner.  The aim of this review is to present an overview of the categories of involuntary movements, along with examples of common acquired and genetic causes, and an approach to history-taking, examination, and treatment.

Deep Brain Stimulation Results in Greater Symptomatic Improvement in Tourette Syndrome than Conservative Measures: A Meta-Analysis

INTRODUCTION

Deep brain stimulation (DBS) has emerged as a safe and effective therapy for refractory Tourette syndrome (TS). Recent studies have identified several neural targets as effective in reducing TS symptoms with DBS, but, to our knowledge, none has compared the effectiveness of DBS with conservative therapy.

METHODS

A literature review was performed to identify studies investigating adult patient outcomes reported as Yale Global Tic Severity Scale (YGTSS) scores after DBS surgery, pharmacotherapy, and psychotherapy. Data were pooled using a random-effects model of inverse variance-weighted meta-analysis (n = 168 for DBS, n = 131 for medications, and n = 154 for behavioral therapy).

RESULTS

DBS resulted in a significantly greater reduction in YGTSS total score (49.9 ± 17.5%) than pharmacotherapy (22.5 ± 15.2%, p = 0.001) or psychotherapy (20.0 ± 11.3%, p < 0.001), with a complication (adverse effect) rate of 0.15/case, 1.13/case, and 0.60/case, respectively.

CONCLUSION

Our data suggest that adult patients with refractory TS undergoing DBS experience greater symptomatic improvement with surprisingly low morbidity than can be obtained with pharmacotherapy or psychotherapy.

Spatio-temporal structure of single neuron subthalamic activity identifies DBS target for anesthetized Tourette syndrome patients

OBJECTIVE

Deep brain stimulation (DBS) of basal ganglia effectively tackles motor symptoms of movement disorders such as Tourette syndrome (TS). The precise location of target stimulation site determines the range of clinical outcome in DBS patients, and the occurrence of side-effects of DBS. DBS implant procedures currently localize stimulation target relying on a combination of pre-surgical imaging, standardized brain atlases and on-the-spot clinical tests. Here we show that temporal structure of single unit activity in subthalamic nucleus (STN) of patients affected by pure TS can contribute to identify the optimal target location of DBS.

APPROACH

Neural activity was recorded at different depths within STN with microelectrodes during DBS implant surgery. Depth specific neural features were extracted and correlated with the optimal depth for tic control.

MAIN RESULTS

We describe for the first time temporal spike patterns of single neurons from sensorimotor STN of anesthetized TS patients. A large fraction of units (31.2%) displayed intense bursting in the delta band (<4 Hz). The highest firing irregularity and hence the higher density of bursting units (42%) were found at the optimal spot for tic control. Discharge patterns irregularity and dominant oscillations frequency (but not firing rate) carried significant information on optimal target.

SIGNIFICANCE

We found single unit activity features in the STN of TS patients reliably associated to optimal DBS target site for tic control. In future works measures of firing irregularity could be integrated with current target localization methods leading to a more effective and safer DBS for TS patients.

A Review of Cognitive Outcomes Across Movement Disorder Patients Undergoing Deep Brain Stimulation

Introduction: Although the benefit in motor symptoms for well-selected patients with deep brain stimulation (DBS) has been established, cognitive declines associated with DBS can produce suboptimal clinical responses. Small decrements in cognition can lead to profound effects on quality of life. The growth of indications, the expansion of surgical targets, the increasing complexity of devices, and recent changes in stimulation paradigms have all collectively drawn attention to the need for re-evaluation of DBS related cognitive outcomes.

Methods: To address the impact of cognitive changes following DBS, we performed a literature review using PubMed. We searched for articles focused on DBS and cognition. We extracted information about the disease, target, number of patients, assessment of time points, cognitive battery, and clinical outcomes. Diseases included were dystonia, Tourette syndrome (TS), essential tremor (ET), and Parkinson's disease (PD).

Results: DBS was associated with mild cognitive issues even when rigorous patient selection was employed. Dystonia studies reported stable or improved cognitive scores, however one study using reliable change indices indicated decrements in sustained attention. Additionally, DBS outcomes were convoluted with changes in medication dose, alleviation of motor symptoms, and learning effects. In the largest, prospective TS study, an improvement in attentional skills was noted, whereas smaller studies reported variable declines across several cognitive domains. Although, most studies reported stable cognitive outcomes. ET studies largely demonstrated deficits in verbal fluency, which had variable responses depending on stimulation setting. Recently, studies have focused beyond the ventral intermediate nucleus, including the post-subthalamic area and zona incerta. For PD, the cognitive results were heterogeneous, although deficits in verbal fluency were consistent and related to the micro-lesion effect.

Conclusion: Post-DBS cognitive issues can impact both motor and quality of life outcomes. The underlying pathophysiology of cognitive changes post-DBS and the identification of pathways underpinning declines will require further investigation. Future studies should employ careful methodological designs. Patient specific analyses will be helpful to differentiate the effects of medications, DBS and the underlying disease state, including disease progression. Disease progression is often an underappreciated factor that is important to post-DBS cognitive issues.

A marked point process approach for identifying neural correlates of tics in Tourette Syndrome

We propose a novel interpretation of local field potentials (LFP) based on a marked point process (MPP) framework that models relevant neuromodulations as shifted weighted versions of prototypical temporal patterns. Particularly, the MPP samples are categorized according to the well known oscillatory rhythms of the brain in an effort to elucidate spectrally specific behavioral correlates. The result is a transient model for LFP. We exploit data-driven techniques to fully estimate the model parameters with the added feature of exceptional temporal resolution of the resulting events. We utilize the learned features in the alpha and beta bands to assess correlations to tic events in patients with Tourette Syndrome (TS). The final results show stronger coupling between LFP recorded from the centromedian-paraficicular complex of the thalamus and the tic marks, in comparison to electrocorticogram (ECoG) recordings from the hand area of the primary motor cortex (M1) in terms of the area under the curve (AUC) of the receiver operating characteristic (ROC) curve.

Tourette Syndrome: A Mini-Review

The purpose of this mini-review is to provide the latest information on epidemiology, pathophysiology, diagnosis, and treatment of Tourette syndrome (TS). The authors conducted a literature search of available sources describing the issue of tic disorders with special focus on TS and made a comparison and evaluation of relevant findings. The results of this mini-review indicate that TS is a complex disorder, which has a significant impact on the quality of life of both the patients and his/her family. Therefore, early and proper diagnosis and treatment are necessary in order to reduce or even eliminate both symptoms and social burden of the patient. This requires a multidisciplinary management approach in order to meet the patients' special needs. Future research should focus on neuroimaging, new neurotransmitter targets, in functional neurosurgery, as well as the effect of non-pharmacological psychotherapies for these people.

Altered topology of structural brain networks in patients with Gilles de la Tourette syndrome

Gilles de la Tourette syndrome is a neurodevelopmental disorder characterized by tics. Abnormal neuronal circuits in a wide-spread structural and functional network involved in planning, execution and control of motor functions are thought to represent the underlying pathology. We therefore studied changes of structural brain networks in 13 adult GTS patients reconstructed by diffusion tensor imaging and probabilistic tractography. Structural connectivity and network topology were characterized by graph theoretical measures and compared to 13 age-matched controls. In GTS patients, significantly reduced connectivity was detected in right hemispheric networks. These were furthermore characterized by significantly reduced local graph parameters (local clustering, efficiency and strength) indicating decreased structural segregation of local subnetworks. Contrasting these results, whole brain and right hemispheric networks of GTS patients showed significantly increased normalized global efficiency indicating an overall increase of structural integration among distributed areas. Higher global efficiency was associated with tic severity (R = 0.63, p = 0.022) suggesting the clinical relevance of altered network topology. Our findings reflect an imbalance between structural integration and segregation in right hemispheric structural connectome of patients with GTS. These changes might be related to an underlying pathology of impaired neuronal development, but could also indicate potential adaptive plasticity.

The colorful spectrum of Tourette syndrome and its medical, surgical and behavioral therapies

Tourette syndrome (TS) is a common neuropsychiatric disorder, more common in males than females, with onset before age 18. TS is characterized by multiple motor tics and one or more vocal/phonic tics, persisting for more than a year. Tics are unvoluntary, abrupt, rapid, repetitive, but non-rhythmic movements or sounds (vocalizations). They are preceded by an inner urge. Tics can be temporarily suppressed, but this leads to a powerful re-emergence. The performance of tics results in immediate but transient relief. Motor and vocal tics are classified as simple or complex. Tics emerge many times during the day and display spontaneous fluctuations in frequency, type, severity and complexity. Tics improve during concentration, worsen during relaxation or when under stress and occasionally are persistent in sleep. Psychiatric comorbidities such as attention deficit hyperactivity disorder (ADHD), obsessive compulsive disorder (OCD) and others frequently are present. Patients, families and teachers benefit from receiving instruction regarding the character of TS and its specific symptoms and from receiving counseling. Pharmacological treatment is not always necessary. Atypical antipsychotics (e.g. risperidone, ziprasidone, olanzapine, aripiprazole) are often the first-line treatment; typical antipsychotics (e.g. haloperidol, pimozide, fluphenazine), benzodiazepines (clonazepam) and tetrabenazine are employed less frequently. Alpha adrenergic agonists (clonidine, guanfacine), the selective noradrenaline re-uptake inhibitor, atomoxetine, and the amphetamine-like stimulant, methylphenidate, are useful in patients with tics and ADHD; selective serotonin re-uptake inhibitors can be useful in individuals with tics and OCD. Botulinum toxin can be effective in focal tics. In severe, treatment-resistant TS, deep brain stimulation may be beneficial.

Neurodevelopmental disorders in young violent offenders: Overlap and background characteristics

Neurodevelopmental disorders (Attention-Deficit/Hyperactivity Disorder (ADHD), Autism Spectrum Disorder (ASD), tic disorder, intellectual disability (ID)), in prison populations have received increased attention but the focus has generally been on one single condition leaving out the global picture. This study assessed the prevalence and overlap of neurodevelopmental disorders (NDD) in a consecutive cohort (n=270) of young adult male offenders (age 18-25 years), sentenced for "hands-on" violent offences and serving prison time in Swedish prisons. Seventy-one percent of all who met inclusion criteria participated. Comprehensive clinical assessments were carried out including history of early antisocial behavior and maladjustment, self-report questionnaires and an intelligence test. Sixty-three percent of the study group met DSM-IV criteria for childhood ADHD, 43% for ADHD in adulthood, 10% met criteria for an ASD, 6% for Tourette syndrome, and 1% for ID. Twenty-two percent had borderline intellectual functioning. A substantial rate of overlap between the NDDs was found. The combined NDD group had an earlier onset of antisocial behavior, had more aggressive behavior and lower school achievements than the non-NDD group. The results highlight the need for prison and probation services to be attentive of and screen for neurodevelopmental disorders in young violent offenders.

Tics in the Pediatric Population: Pragmatic Management

BACKGROUND

Primary tic disorders, notably Tourette syndrome, are very common movement disorders in childhood. However, the management of such patients still poses great therapeutic challenges to medical professionals.

METHODS

Based on a synthesis of the available guidelines published in Europe, Canada, and the United States, coupled with more recent therapeutic developments, the authors provide a pragmatic guide to aid clinicians in deciding when and how to treat patients who have primary tic disorders.

RESULTS

After a systematic assessment of tics and common neuropsychiatric comorbidities (primarily attention-deficit hyperactivity disorder [ADHD] and obsessive-compulsive disorder [OCD]), the first step in treatment is a comprehensive psychoeducation of patients and families that addresses the protean phenomenology of tics and associated behaviors, coping mechanisms, prognosis, and treatment options. When more active intervention beyond watchful monitoring is indicated, hierarchical evaluation of treatment targets (i.e., tics vs. comorbid behavioral symptoms) is crucial. Behavioral treatments for tics are restricted to older children and are not readily available to all centers, mainly due to the paucity of well-trained therapists. Pharmacological treatments, such as antipsychotics for tics, stimulants and atomoxetine for ADHD, and α2A-agonists for children with tics plus ADHD, represent widely available and effective treatment options, but safety monitoring must be provided. Combined polypharmacological and behavioral/pharmacological approaches, as well as neuromodulation strategies, remain under-investigated in this population of patients.

CONCLUSIONS

The treatment of children with tics and Tourette syndrome is multifaceted. Multidisciplinary teams with expertise in neurology, psychiatry, psychology, and pediatrics may be helpful to address the complex needs of these children.

Deutetrabenazine in Tics Associated with Tourette Syndrome

Background

Deutetrabenazine, an inhibitor of vesicular monoamine transporter type 2 (VMAT2) depletes presynaptic dopamine and is useful in the treatment of hyperkinetic movement disorders. This study explored the safety, tolerability, and preliminary efficacy of deutetrabenazine in adolescents with moderate-to-severe tics associated with Tourette syndrome (TS).

Methods

In this open-label study of 12–18-year-old patients with TS-related tics, deutetrabenazine was titrated up to 36 mg/day over 6 weeks to adequately suppress tics without bothersome adverse effects (AEs), followed by maintenance at optimal dose for 2 weeks. An independent blinded rater assessed tic severity using the Yale Global Tic Severity Scale (YGTSS), which was the primary outcome measure. Secondary outcome measures included the TS Clinical Global Impression (TS-CGI) and TS Patient Global Impression of Change (TS-PGIC).

Results

Twenty-three enrolled patients received deutetrabenazine and had at least 1 post-baseline YGTSS assessment. The mean (SD [standard deviation]) baseline YGTSS Total Tic Severity Score (TTS) was 31.6 (7.9) and had decreased by 11.6 (8.2) points at week 8, a 37.6% reduction in tic severity (p<0.0001). The TS-CGI score improved by 1.2 (0.81) points (p<0.0001) and the TS-PGIC results at week 8 indicated that 76% of patients were much improved or very much improved compared with baseline. The mean (SD) daily deutetrabenazine dose at week 8 was 32.1 (6.6) mg (range 18–36 mg). One week after withdrawal of deutetrabenazine, the TTS scores increased by 5.6 (8.4) points, providing confirmation of the drug effect. No serious or severe adverse events were reported.

Discussion

The results of this open-label 8-week study suggest that deutetrabenazine is safe and associated with improvement in tic severity in adolescents with TS and troublesome tics.