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

DiMANI: diffusion MRI for anatomical nuclei imaging-Application for the direct visualization of thalamic subnuclei

The thalamus is a centrally located and heterogeneous brain structure that plays a critical role in various sensory, motor, and cognitive processes. However, visualizing the individual subnuclei of the thalamus using conventional MRI techniques is challenging. This difficulty has posed obstacles in targeting specific subnuclei for clinical interventions such as deep brain stimulation (DBS). In this paper, we present DiMANI, a novel method for directly visualizing the thalamic subnuclei using diffusion MRI (dMRI). The DiMANI contrast is computed by averaging, voxelwise, diffusion-weighted volumes enabling the direct distinction of thalamic subnuclei in individuals. We evaluated the reproducibility of DiMANI through multiple approaches. First, we utilized a unique dataset comprising 8 scans of a single participant collected over a 3-year period. Secondly, we quantitatively assessed manual segmentations of thalamic subnuclei for both intra-rater and inter-rater reliability. Thirdly, we qualitatively correlated DiMANI imaging data from several patients with Essential Tremor with the localization of implanted DBS electrodes and clinical observations. Lastly, we demonstrated that DiMANI can provide similar features at 3T and 7T MRI, using varying numbers of diffusion directions. Our results establish that DiMANI is a reproducible and clinically relevant method to directly visualize thalamic subnuclei. This has significant implications for the development of new DBS targets and the optimization of DBS therapy.

Microlesion Effect Induced by Electrode Implantation in the Posteroventral Globus Pallidus Interna for Severe Dystonic Tics

Background

Tourette syndrome (TS) is a neurologic condition characterized by motor and phonic tics. Dystonic tics, including blepharospasm, are considered atypical or unusual in severe TS.

Case Report

We report a severe case of TS with facial dystonic tics resembling blepharospasm in which the microlesion effect and a sustained therapeutic effect was observed with bilateral globus pallidus interna (GPi) deep brain stimulation (DBS).

Discussion

Bilateral GPi DBS can be beneficial for blepharospasm-like tics and severe symptoms of TS. The improvements seen can be explained by the microlesion effect induced by DBS lead placement in the GPi.

Deep Brain Stimulation for the Management of Refractory Neurological Disorders: A Comprehensive Review

In recent decades, deep brain stimulation (DBS) has been extensively studied due to its reversibility and significantly fewer side effects. DBS is mainly a symptomatic therapy, but the stimulation of subcortical areas by DBS is believed to affect the cytoarchitecture of the brain, leading to adaptability and neurogenesis. The neurological disorders most commonly studied with DBS were Parkinson's disease, essential tremor, obsessive-compulsive disorder, and major depressive disorder. The most precise approach to evaluating the location of the leads still relies on the stimulus-induced side effects reported by the patients. Moreover, the adequate voltage and DBS current field could correlate with the patient's symptoms. Implantable pulse generators are the main parts of the DBS, and their main characteristics, such as rechargeable capability, magnetic resonance imaging (MRI) safety, and device size, should always be discussed with patients. The safety of MRI will depend on several parameters: the part of the body where the device is implanted, the part of the body scanned, and the MRI-tesla magnetic field. It is worth mentioning that drug-resistant individuals may have different pathophysiological explanations for their resistance to medications, which could affect the efficacy of DBS therapy. Therefore, this could explain the significant difference in the outcomes of studies with DBS in individuals with drug-resistant neurological conditions.

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

AIM

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

METHOD

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

RESULTS

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

CONCLUSION

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

Tourette syndrome and other tic disorders of childhood

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

Optogenetic Low-Frequency Stimulation of Principal Neurons, but Not Parvalbumin-Positive Interneurons, Prevents Generation of Ictal Discharges in Rodent Entorhinal Cortex in an In Vitro 4-Aminopyridine Model

Low-frequency electrical stimulation is used to treat some drug-resistant forms of epilepsy. Despite the effectiveness of the method in suppressing seizures, there is a considerable risk of side effects. An optogenetic approach allows the targeting of specific populations of neurons, which can increase the effectiveness and safety of low-frequency stimulation. In our study, we tested the efficacy of the suppression of ictal activity in entorhinal cortex slices in a 4-aminopyridine model with three variants of low-frequency light stimulation (LFLS): (1) activation of excitatory and inhibitory neurons (on Thy1-ChR2-YFP mice), (2) activation of inhibitory interneurons only (on PV-Cre mice after virus injection with channelrhodopsin2 gene), and (3) hyperpolarization of excitatory neurons (on Wistar rats after virus injection with archaerhodopsin gene). Only in the first variant did simultaneous LFLS of excitatory and inhibitory neurons replace ictal activity with interictal activity. We suggest that LFLS caused changes in the concentration gradients of K⁺ and Na⁺ cations across the neuron membrane, which activated Na-K pumping. According to the mathematical modeling, the increase in Na-K pump activity in neurons induced by LFLS led to an antiepileptic effect. Thus, a less specific and generalized optogenetic effect on entorhinal cortex neurons was more effective in suppressing ictal activity in the 4-aminopyridine model.

TikTok Tourette's: Are We Witnessing a Rise in Functional Tic-Like Behavior Driven by Adolescent Social Media Use?

Perceptions of Tourette syndrome (TS) and tic disorders are often driven by social media. During the COVID-19 pandemic, social media consumption greatly increased, particularly in the adolescent population. In parallel with increased social media consumption, there has also been an increase in tic severity and functional tic-like behavior (FTLB). Given that many of the tic videos posted on social media are misleading, perpetuate false beliefs about TS, or reinforce tic-like behaviors, there is increasing concern that these videos are driving the rapid increase in FTLBs. Several studies have reviewed newly presenting cases of FTLB and have found shared characteristics, including that a higher proportion of affected individuals are female, there is a low proportion with a history of childhood or family tics, and symptom onset is typically acute and develops in the teenage years. In addition, the quality of the tics seen in association with FTLB mirrors many of the tics seen on popular social media channels, with higher rates of coprophenomena, tic attacks, and involvement of the trunk and extremities than is seen with typical tics. FTLBs are likely a specific subgroup of functional tics largely influenced by the portrayal of and growing popularity of functional tics posted on social media during the COVID-19 pandemic. However, several factors, including increased anxiety, social isolation, and social media use in general during the pandemic are likely also contributing factors to the surge of FTLBs seen recently. In this era of increased social media consumption, it will become increasingly important for clinicians to educate patients about where and how medical information is spread, to ensure the best possible diagnosis, treatment, and outcomes for patients.

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.

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

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

Reexperiencing and anxious arousal symptoms in relation to volumes of thalamus nuclei in posttraumatic stress spectrum adults

INTRODUCTION

Trauma reexperiencing is dominated by recollection of sensory-perceptual elements of the trauma, pointing to involvement of the sensory thalamus. This study examined posttraumatic stress symptoms in relation to volumes of thalamic nuclei that were grouped based on their predominant functions. We hypothesized that reexperiencing, controlling for other symptom dimensions, would correlate with volumes of thalamic nuclei involved in primary and higher-order sensory processing.

METHODS

Seventy-two trauma-exposed adults were interviewed with the Clinician Administered PTSD Scale for DSM-IV and underwent 3T magnetic resonance imaging. Scores were derived for reexperiencing, anxious arousal, dysphoric arousal, emotional numbing, and avoidance symptoms. These were entered as simultaneous predictors in five separate regression analyses, with age, sex, and total thalamus volume as covariates, predicting volumesf of five thalamus nuclear groupings corrected for intracranial volume: Specific sensory, associative-sensory, associative-cognitive, intralaminar, and motor groupings.

RESULTS

Reexperiencing symptoms were significantly positively correlated with volumes of the motor thalamic grouping, which included the ventral anterior, ventral lateral, and ventromedial nuclei. Anxious arousal was significantly negatively correlated with volumes of all five thalamic groupings.

CONCLUSIONS

Reexperiencing symptoms were correlated with volumes of the motor thalamus, while anxious arousal symptoms were related to all thalamic subregion volumes. Thalamic nuclei involved in motor functions, including oculomotor control and motor planning, may be implicated in posttraumatic reexperiencing symptoms.

Surgical Outcomes in Rare Movement Disorders: A Report of Seventeen Patients from India and Review of Literature

Background:

Rare movement disorders (RMDs) throw remarkable challenges to their appropriate management particularly when they are medically refractory. We studied the outcome of functional neurosurgery among patients with RMDs.

Methods:

Retrospective chart-review from 2006 to 2021 of patients with RMDs who underwent either Deep brain Stimulation (DBS) or lesional surgeries in the department of Neurology and Neurosurgery at a tertiary care centre.

Results:

Seventeen patients were included. Generalized dystonia (11 patients, 64.7%) and tremor (5 patients, 29.4%) were the most common indication for surgery whereas, Wilson’s disease (8 patients, 47.1%) and Neurodegeneration with brain iron accumulation (5 patients, 29.4%) were the most common aetiology. Sixteen patients (94.1%) had objective clinical improvement. Significant improvement was noted in the dystonia motor scores both at 6-months and 12-months follow-up (n = 11, p-value of <0.01 and 0.01 respectively). Comparison between DBS and lesional surgery showed no significant difference in the outcomes (p = 0.95 at 6-months and p = 0.53 at 12-months), with slight worsening of scores in the DBS arm at 12-months. Among five patients of refractory tremor with Wilson’s disease, there was remarkable improvement in the tremor scores by 85.0 ± 7.8% at the last follow-up. Speech impairment was the main complication observed with most of the other adverse events either transient or reversible.

Discussion:

Surgical options should be contemplated among patients with disabling medically refractory RMDs irrespective of the aetiology. Key to success lies in appropriate patient selection. In situations when DBS is not feasible, lesional surgeries can offer an excellent alternative with comparable efficacy and safety.

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

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

Tourette Syndrome Treatment Updates: a Review and Discussion of the Current and Upcoming Literature

Purpose of Review

This study aims to examine the treatments currently available for Tourette syndrome (TS) and to discuss evolving therapies, spanning behavioral, pharmacologic, complementary and alternative medicine, and neuromodulation approaches.

Recent Findings

Behavioral therapies have undergone several modifications to improve accessibility, including transitioning to a virtual format which is particularly important in the current pandemic. There are several recent or ongoing pharmacologic studies that have shown promise including the selective D1 receptor antagonist ecopipam and various cannabinoid compounds. Adaptive DBS may enable the physiologic markers of tics to determine stimulation parameters and improve tic outcomes related to neuromodulation.

Summary

In recent years, there has been a wealth of research across multiple treatment domains in the TS field. This review highlights exciting and new potential options for the future treatment of patients with TS.

Efficacy of deep brain stimulation of the anterior-medial globus pallidus internus in tic and non-tic related symptomatology in refractory Tourette syndrome

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Report of clinical outcomes of 5 patients with Tourette syndrome treated with anteromedial globus pallidus deep brain stimulation.

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All patients showed improvement in tics over a median follow up period of 37.4 months.

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Improvement in psychiatric outcome measures are specifically noted with a reduction in medication burden from the time of surgery to the last follow up.

Introduction

Although refractory Tourette Syndrome (TS) is rare, it poses great challenges in clinical practice. Co-morbid psychiatric symptoms often occur, negatively impacting quality of life. Deep brain stimulation (DBS) targeting different brain structures seems effective for tics, but specific literature regarding response of psychiatric symptoms is more limited.

This study aimed to assess the outcome of tics and non-tic related symptomatology in refractory TS treated with antero-medial globus pallidus interna (amGPi) DBS.

Methods

We included all patients with refractory TS (January 2013–August 2020) from the Brain Nerve Centre and Steve Biko Academic Hospital, Pretoria, South Africa, treated with bilateral amGPi DBS; retrospective baseline, early (up to 3 months) post-DBS follow-up assessment data, as well as prospective data from the latest follow-up (mean 37.4 months) were collected using standardised scoring tools and scales.

Results

Five patients were identified. Tics decreased by 63,9% (p = 0,002); quality of life improved by 39,8% (p = 0,015); self-injurious behaviour ceased; obsessive–compulsive symptoms resolved in all but one. The number of different chronic medications used more than halved. Transient stimulation-related adverse events occurred in four patients.

Conclusion

This study contributes to the data of the efficacy of amGPi-targeted DBS in refractory TS, showing improvement in quality of life and both tic- and non-tic-related symptomatology..

Deep brain stimulation of anteromedial globus pallidus internus improved OCD rather than tics in a Gilles de la Tourette syndrome patient

A 32-year-old gentleman with refractory Gilles de la Tourette syndrome went on a DBS procedure on anteromedial globus pallidus internus. At the most suitable adjustment, the OCD component of his disease improved almost completely while his tics remained unchanged which was in contrast with other previous studies. Moreover, variations in symptoms were seen in response to different adjustments. We discuss that these variations and fluctuations in the therapeutic outcomes may be due to differences in physiological conditions of tic- or OCD-specified pathways and areas including distinct stimulation threshold and occurrence of neuroplasticity in neural circuits which may determine the responsiveness of each pathway or circuit to a specific stimulus. At last, we suggest that pathways and circuits should be targeted for DBS rather than single components; as these components may be involved in multiple pathways, related to different pathophysiological states.

Transient Complete Resolution of Tourette Syndrome Symptoms Following Personalized Depth Electrode Placement

Treatment refractory Tourette syndrome has been shown to be improved with deep brain stimulation, but with multiple possible stimulation locations and variable and incomplete benefit. This study presents a single case of complete amelioration of motor and verbal tics in a patient with Tourette syndrome during placement of 12 stereo-EEG electrodes to identify optimal targets for permanent stimulating electrodes. Subsequently, substantial improvement in motor and verbal tic frequency occurred with placement and programming of permanent electrodes in bilateral globus pallidus internus and nucleus accumbens, but without the complete resolution seen during depth electrode placement. We suggest that simultaneous stimulation at multiple patient-specific targets could provide effective control of Tourette symptomatology, but further study will be needed.

Effects of stereotactic radiofrequency thermocoagulation in the globus pallidus internus on refractory tic disorders

OBJECTIVE

To investigate the effect of stereotactic radiofrequency thermocoagulation in the globus pallidus internus on refractory tic disorders.

MATERIALS AND METHODS

Forty patients with refractory tic disorders were enrolled between January 2015 and July 2017 to experience stereotactic radiofrequency thermocoagulation in the globus pallidus internus. All clinical data, Yale Global Tic Severity Scale (YGTSS) scores, serum dopamine (SDA), and 5-hydroxytryptamine (5-HT) were analyzed.

RESULTS

Radiofrequency thermocoagulation was successfully performed in all patients. Periprocedural complications occurred in two patients (5.0%), one with fever (2.5%) and one with a urination disorder (2.5%); both returned to normal after treatment. After 12 months of follow-ups, excellent improvement was exhibited in 18 patients (45.0%), marked improvement in 10 (25.0%), good improvement in 9 (22.5%), and invalid in 3 (7.5%), with a total efficacy rate of 92.5% (37/40). Twenty-eight patients (70%) showed excellent or marked improvement without additional treatment after surgery. YGTSS scores were significantly (p < 0.05) decreased after compared with before thermocoagulation. SDA was significantly (p < 0.05) decreased 6 months (80.78 ± 18.82 ng/ml) and 12 months (75.65 ± 15.23 ng/ml) after compared with before (125.63 ± 35.26 ng/ml) surgery, whereas 5-HT was significantly (p < 0.05) increased 6 months (58.93 ± 16.88 ng/ml) and 12 months (62.63 ± 15.21 ng/ml) after compared with before (35.62 ± 3.41 ng/ml) surgery.

CONCLUSION

Stereotactic radiofrequency thermocoagulation can be safely applied in the globus pallidus internus to treat refractory tic disorders, resulting in significant tic symptom relief and a decrease in SDA but increase in 5-HT.

Cholinergic Deep Brain Stimulation for Memory and Cognitive Disorders

Memory and cognitive impairment as sequelae of neurodegeneration in Alzheimer's disease and age-related dementia are major health issues with increasing social and economic burden. Deep brain stimulation (DBS) has emerged as a potential treatment to slow or halt progression of the disease state. The selection of stimulation target is critical, and structures that have been targeted for memory and cognitive enhancement include the Papez circuit, structures projecting to the frontal lobe such as the ventral internal capsule, and the cholinergic forebrain. Recent human clinical and animal model results imply that DBS of the nucleus basalis of Meynert can induce a therapeutic modulation of neuronal activity. Benefits include enhanced activity across the cortical mantle, and potential for amelioration of neuropathological mechanisms associated with Alzheimer's disease. The choice of stimulation parameters is also critical. High-frequency, continuous stimulation is used for movement disorders as a way of inhibiting their output; however, no overexcitation has been hypothesized in Alzheimer's disease and lower stimulation frequency or intermittent patterns of stimulation (periods of stimulation interleaved with periods of no stimulation) are likely to be more effective for stimulation of the cholinergic forebrain. Efficacy and long-term tolerance in human patients remain open questions, though the cumulative experience gained by DBS for movement disorders provides assurance for the safety of the procedure.

Current Management of Tics and Tourette Syndrome: Behavioral, Pharmacologic, and Surgical Treatments

Tourette syndrome is a heterogeneous neurobehavioral disorder manifested by childhood-onset motor and phonic tics, often accompanied by a variety of behavioral comorbidities, including attention deficit and obsessive compulsive disorder. Treatment must be tailored to the needs and goals of the individual patients and their families. All patients should receive education on the condition and, if possible, engage behavioral therapy targeted towards tics and/or comorbidities. Pharmacological therapies, such as alpha agonists, topiramate, and vesicular monoamine transport type 2 inhibitors, are generally used as first-line therapies in patients with troublesome tics that are not controlled by behavioral therapy or when the latter is not available or accessible. Botulinum toxin injections can be used in patients with bothersome focal tics. Second-line therapy includes antipsychotics, such as fluphenazine, aripiprazole, risperidone, and ziprasidone. These medications are generally efficacious but carry the risk of metabolic syndrome, tardive dyskinesia, and other side effects. Much more research is needed before novel therapies such as cannabis-derived products or transcranial magnetic stimulation can be recommended. There is promise in ongoing clinical trials with D1 receptor antagonist ecopipam and other experimental therapeutics. Patients with tics that are refractory to conventional treatments may be candidates for deep brain stimulation, but further studies are needed to determine the optimal target selection.

Stereotactic radiofrequency thermocoagulation application in the anterior limbs of patients' internal capsules in treating intractable tic disorders

Purpose: To investigate the effect of applying stereotactic radiofrequency thermocoagulation in the anterior limbs of patients' internal capsules in treating intractable tic disorders.Materials and methods: Patients diagnosed with intractable tic disorders were prospectively enrolled and treated using stereotactic radiofrequency thermocoagulation in the anterior limbs of the internal capsules. Periprocedural complications, effects, and follow-up outcomes were then analyzed.Results: Fifty patients were enrolled, including 38 with Tourette syndrome and 12 with persistent refractory vocal or motor tic disorders. The radiofrequency thermocoagulation procedure was performed successfully in all patients. Five participants (10%) experienced periprocedural complications, including one having a slight hemiplegia, two developing fevers (4%), and two developing urination disorders (4%). The participants underwent a follow-up for 12 months, with excellent effects being achieved in 23 patients (46%), prominent results in 13 (26%), good results in 10 (20%), and invalid results in 4 (8%), reaching an efficacy rate of 92% (46/50). Thirty-six patients experienced excellent and prominent effects, with no additional management after the radiofrequency ablation being needed, achieving a success rate of 72%. After radiofrequency thermocoagulation, the Yale Global Tic Severity Scale (YGTSS) scores were significantly reduced (p < .01) when compared with those before the procedure. Following this procedure, participants' serum dopamine levels (SDA) significantly decreased (p < .05), while their serotonin levels were significantly elevated (p < .05) when compared to the measurements taken before the procedure.Conclusion: Stereotactic radiofrequency thermocoagulation applied to the anterior limbs of patients' internal capsules may be effective for treating intractable tic disorders, without risk of serious complications.

Tics and Tourette's syndrome

Tics and Tourette's syndrome are common hyperkinetic movement disorders seen mostly in the pediatric age group. Tics are defined as sudden, rapid, recurrent, nonrhythmic motor movements or vocalization, generally preceded by urge. Tourette's syndrome is defined as the presence of both motor and phonic tics for more than 1 year in patients with onset less than 18 years old. Most of these hyperkinetic movement disorders improve in adulthood. This review emphasizes the clinical pearls in the diagnosis and distinguishing it from other movement disorders. The treatment ranges from behavioral therapies, medical management, and also surgical treatment such as deep brain stimulation that is limited to refractory patients.

Treatment of dystonia and tics

Treatment of dystonia and tics continues to evolve. In dystonia, while oral agents such as benzodiazepines, baclofen and anticholinergics remain in use, botulinum toxin (BoNT) continues to be regarded as the treatment of choice for focal and segmental dystonia, but new preparations are being studied. While deep brain stimulation (DBS) has typically focused on targeting the globus pallidus internus (GPi) when treating dystonia, more recent research has expanded the targets to include subthalamic nucleus (STN) and other targets. In addition to DBS, thalamotomies continue to show therapeutic benefit in focal hand dystonias. Treatment of tics includes a growing armamentarium of options besides the three FDA-approved drugs, all dopamine receptor blockers (haloperidol, pimozide and aripiprazole). Because of lower risk of adverse effects, dopamine depleters (e.g. tetrabebazine, deutetrabenazine, and valbenazine), along with novel D1 receptor antagonists, are currently studied as treatment alternatives in patients with tics. Practice guidelines for the treatment of tics and Tourette syndrome have been recently updated. Data regarding the use of DBS in treatment of tics remains relatively sparse, but international registries have expanded our understanding of the effect of stimulation at several targets.