Search

Objective: The objective of this study was to evaluate the accuracy of the SureTune3 postoperative imaging software in determining the location of a deep brain stimulation (DBS) electrode based on clinical outcomes and the adverse effects (AEs) observed., Methods: Twenty-six consecutive patients with Parkinson disease (n = 17), essential tremor (n = 8), and dystonia (n = 1) who underwent bilateral DBS surgery (52 electrodes) were included in this study. Presurgical assessments were performed in all patients prior to surgery and at 3 and 6 months after surgery, using quality-of-life and clinical scales in each case. The SureTune3 software was used to evaluate the anatomical positioning of the DBS electrodes., Results: Following DBS surgery, motor and quality-of-life improvement was observed in all patients. Different AEs were detected in 12 patients, in 10 of whom (83.3%) SureTune3 related the symptoms to the positioning of an electrode. A clinical association was observed with SureTune3 for 48 of 52 (92.3%) electrodes, whereas no association was found between the AEs or clinical outcomes and the SureTune3 reconstructions for 4 of 52 electrodes (7.7%) from 4 different patients. In 2 patients, the contact chosen was modified based on the SureTune3 data, and in 2 cases, the software helped determine that second electrode replacement surgery was necessary., Conclusions: The anatomical position of electrodes analyzed with SureTune3 software was strongly correlated with both the AEs and clinical outcomes. Thus, SureTune3 may be useful in clinical practice, and it could help improve stimulation parameters and influence decisions to undertake electrode replacement surgery., (Copyright © 2022 Elsevier Inc. All rights reserved.)

Purpose of Review: This article discusses the most recent findings regarding the diagnosis, classification, and management of genetic and idiopathic dystonia., Recent Findings: A new approach to classifying dystonia has been created with the aim to increase the recognition and diagnosis of dystonia. Molecular biology and genetic studies have identified several genes and biological pathways involved in dystonia., Summary: Dystonia is a common movement disorder involving abnormal, often twisting, postures and is a challenging condition to diagnose. The pathophysiology of dystonia involves abnormalities in brain motor networks in the context of genetic factors. Dystonia has genetic, idiopathic, and acquired forms, with a wide phenotypic spectrum, and is a common feature in complex neurologic disorders. Dystonia can be isolated or combined with another movement disorder and may be focal, segmental, multifocal, or generalized in distribution, with some forms only occurring during the performance of specific tasks (task-specific dystonia). Dystonia is classified by clinical characteristics and presumed etiology. The management of dystonia involves accurate diagnosis, followed by treatment with botulinum toxin injections, oral medications, and surgical therapies (mainly deep brain stimulation), as well as pathogenesis-directed treatments, including the prospect of disease-modifying or gene therapies., (Copyright © 2022 American Academy of Neurology.)

Deep brain stimulation (DBS) is an established intervention for use in pediatric movement disorders, especially dystonia. Although multiple publications have provided guidelines for deep brain stimulation patient selection and programming in adults, there are no evidence-based or consensus statements published for pediatrics. The result is lack of standardized care and underutilization of this effective treatment. To this end, we assembled a focus group of 13 pediatric movement disorder specialists and 1 neurosurgeon experienced in pediatric deep brain stimulation to review recent literature and current practices and propose a standardized approach to candidate selection, implantation target site selection, and programming algorithms. For pediatric dystonia, we provide algorithms for (1) programming for initial session and follow-up sessions, and (2) troubleshooting side effects encountered during programming. We discuss common side effects, how they present, and recommendations for management. This topical review serves as a resource for movement disorders specialists interested in using deep brain stimulation for pediatric dystonia.

Background: DYT6 dystonia belongs to a group of isolated, genetically determined, generalized dystonia associated with mutations in the THAP1 gene., Case Presentation: We present the case of a young patient with DYT6 dystonia associated with a newly discovered c14G>A (p.Cys5Tyr) mutation in the THAP1 gene. We describe the clinical phenotype of this new mutation, effect of pallidal deep brain stimulation (DBS), which was accompanied by two rare postimplantation complications: an early intracerebral hemorrhage and delayed epileptic seizures. Among the published case reports of patients with DYT6 dystonia, the mentioned complications have not been described so far., Conclusions: DBS in the case of DYT6 dystonia is a challenge to thoroughly consider possible therapeutic benefits and potential risks associated with surgery. Genetic heterogeneity of the disease may also play an important role in predicting the development of the clinical phenotype as well as the effect of treatment including DBS. Therefore, it is beneficial to analyze the genetic and clinical relationships of DYT6 dystonia., (© 2022. The Author(s).)

Background: Deep brain stimulation of the internal globus pallidus (GPi DBS) is an invasive therapeutic modality intended to retune abnormal central nervous system patterns and relieve the patient of dystonic or other motor symptoms., Objectives: The aim of the presented research was to determine the neuroanatomical signature of GPi DBS modulation and its association with the clinical outcome., Methods: This open-label fixed-order study with cross-sectional validation against healthy controls analysed the resting-state functional MRI activity changes induced by GPi DBS in 18 dystonia patients of heterogeneous aetiology, focusing on both global (full brain) and local connectivity (local signal homogeneity)., Results: Compared to the switched-off state, the activation of GPi DBS led to the restoration of global subcortical connectivity patterns (in both putamina, diencephalon and brainstem) towards those of healthy controls, with positive direct correlation over large-scale cortico-basal ganglia-thalamo-cortical and cerebellar networks with the clinical improvement. Nonetheless, on average, GPi DBS also seemed to bring local connectivity both in the cortical and subcortical regions farther away from the state detected in healthy controls. Interestingly, its correlation with clinical outcome showed that in better DBS responders, local connectivity defied this effect and approached healthy controls., Conclusions: All in all, the extent of restoration of both these main metrics of interest towards the levels found in healthy controls clearly correlated with the clinical improvement, indicating that the restoration of network state towards more physiological condition may be a precondition for successful GPi DBS outcome in dystonia., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 The Author(s). Published by Elsevier Inc. All rights reserved.)

Intracerebral recordings from movement disorders patients undergoing deep brain stimulation have allowed the identification of pathophysiological patterns in oscillatory activity that correlate with symptom severity. Changes in oscillatory synchrony occur within and across brain areas, matching the classification of movement disorders as network disorders. However, the underlying mechanisms of oscillatory changes are difficult to assess in patients, as experimental interventions are technically limited and ethically problematic. This is why animal models play an important role in neurophysiological research of movement disorders. In this review, we highlight the contributions of translational research to the mechanistic understanding of pathological changes in oscillatory activity, with a focus on parkinsonism and dystonia, while addressing the limitations of current findings and proposing possible future directions., (Copyright © 2022 The Authors. Published by Elsevier Inc. All rights reserved.)

Purpose of Review: Deep brain stimulation (DBS) is an established treatment in several movement disorders, including Parkinson's disease, dystonia, tremor, and Tourette syndrome. In this review, we will review and discuss the most recent findings including but not limited to clinical evidence., Recent Findings: New DBS technologies include novel hardware design (electrodes, cables, implanted pulse generators) enabling new stimulation patterns and adaptive DBS which delivers potential stimulation tailored to moment-to-moment changes in the patient's condition. Better understanding of movement disorders pathophysiology and functional anatomy has been pivotal for studying the effects of DBS on the mesencephalic locomotor region, the nucleus basalis of Meynert, the substantia nigra, and the spinal cord. Eventually, neurosurgical practice has improved with more accurate target visualization or combined targeting. A rising research domain emphasizes bridging neuromodulation and neuroprotection. Recent advances in DBS therapy bring more possibilities to effectively treat people with movement disorders. Future research would focus on improving adaptive DBS, leading more clinical trials on novel targets, and exploring neuromodulation effects on neuroprotection., (© 2022. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

Background: Isolated orofacial dystonia is a rare segmental neurological disorder that affects the eye, mouth, face, and jaws. Current literature on pallidal surgery for orofacial dystonia is limited to case reports and small-scale studies. This study was to investigate clinical outcomes of deep brain stimulation (DBS) of the globus pallidus internus (GPi) in patients with isolated orofacial dystonia., Methods: Thirty-six patients who underwent GPi DBS at Incheon St. Mary's Hospital, The Catholic University of Korea, between 2014 and 2019 were included in this study. Burke-Fahn-Marsden Dystonia Rating Scale, Unified Dystonia Rating Scale, and Global Dystonia Severity Rating Scale were retrospectively retrieved for analysis before surgery, at 6-month follow-up as short-term outcome, and at follow-up over 1 year (12 months to 69 months) as long-term results., Results: Mean total BFMDRS-M scores at the three time points (baseline, 6 months, and over 1 year follow-up) were 11.6 ± 4.9, 6.1 ± 5.2 (50.3 ± 29.9% improvement, p < 0.05), and 4.3 ± 4.2 (65.0 ± 24.2% improvement, p < 0.05), respectively. In terms of UDRS and GDS, improvement rates were 45.1% (p < 0.001) and 47.7% (p < 0.001) at 6 months, and 63.8% (p < 0.001) and 65.7% (p < 0.001) at over 1 year after surgery, respectively., Conclusions: Bilateral GPi DBS in isolated orofacial dystonia can be effective if conservative treatment option fails. Its benefit is not only observed in a short term, but also maintained in a long-term follow-up., (© 2022. The Author(s), under exclusive licence to Springer-Verlag GmbH Austria, part of Springer Nature.)

Purpose of Review: Deep brain stimulation (DBS) is currently the most effective treatment for medically refractory dystonia with globus pallidus internus (GPi) usually the preferred target. Despite the overall success of DBS in dystonia, there remains variability in treatment outcome in both short and long-term follow-up, due to various factors. Factors contributing to variability in outcome comprise 'Dystonia Related' including dystonia classification, semiology, duration, body distribution, orthopaedic deformity, aetiology and genetic cause. The majority of these factors are identifiable from clinical assessment, brain MRI and genetic testing, and therefore merit careful preoperative consideration. 'DBS related' factors include brain target, accuracy of lead placement, stimulation parameters, time allowed for response, neurostimulation technology employed and DBS induced side-effects. In this review, factors contributing to variability in short and long-term dystonia DBS outcome are reviewed and discussed., Recent Findings: The recognition of differential DBS benefit in monogenic dystonia, increasing experience with subthalamic nucleus (STN) DBS and in DBS for Meige syndrome, elucidation of DBS side effects and novel neurophysiological and imaging techniques to assist in predicting clinical outcome., Summary: Improved understanding of factors contributing to variability of DBS outcome in dystonia may assist in patient selection and predicting surgical outcomes., (Copyright © 2022 The Author(s). Published by Wolters Kluwer Health, Inc.)

Hyperkinesias are heterogeneous involuntary movements that significantly differ in terms of clinical and semeiological manifestations, including rhythm, regularity, speed, duration, and other factors that determine their appearance or suppression. Hyperkinesias are due to complex, variable, and largely undefined pathophysiological mechanisms that may involve different brain areas. In this chapter, we specifically focus on dystonia, chorea and hemiballismus, and other dyskinesias, specifically, levodopa-induced, tardive, and cranial dyskinesia. We address the role of neurophysiological studies aimed at explaining the pathophysiology of these conditions. We mainly refer to human studies using surface and invasive in-depth recordings, as well as spinal, brainstem, and transcortical reflexology and non-invasive brain stimulation techniques. We discuss the extent to which the neurophysiological abnormalities observed in hyperkinesias may be explained by pathophysiological models. We highlight the most relevant issues that deserve future research efforts. The potential role of neurophysiological assessment in the clinical context of hyperkinesia is also discussed., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 International Federation of Clinical Neurophysiology. Published by Elsevier B.V. All rights reserved.)

Objective: Dystonia in pantothenate kinase-associated neurodegeneration (PKAN) is progressive despite medication. Deep brain stimulation (DBS) was reported to effectively provide symptom relief. No consensus exists in candidate and target selection for DBS. We aimed to demonstrate effectiveness of subthalamic DBS (STN-DBS) placement in pediatric patients with PKAN., Methods: We reviewed consecutive series of pediatric patients diagnosed with PKAN and treated with STN-DBS from 2016 to 2019 in our institution. Each case was described in detail. Preoperative and postoperative Burke-Fahn-Marsden Dystonia Rating Scale (BFMDRS) were assessed to evaluate functional improvement at follow-up., Results: Seven pediatric patients were included. Mean age of initial onset was 0.6 ± 0.5 years and presentation to clinics was 6.6 ± 1.3 years. Mean preoperative BFMDRS was 73.3 ± 3.5. Following STN-DBS, for mean follow-up duration of 13.0 ± 10.7 months, mean BFMDRS was 37.3 ± 12.6, translating to score improvement of 36.0 ± 12.9 (P < 0.001), and percentage improvement of 49.0 ± 18.0%., Conclusions: This case series demonstrated that STN-DBS is an effective symptom-based treatment for pediatric patients with PKAN., (Copyright © 2022. Published by Elsevier Inc.)

Introduction: Pallidal DBS is an established treatment for severe isolated dystonia. However, its use in disabling and treatment-refractory tardive syndromes (TS) including tardive dyskinesia and tardive dystonia (TD) is less well investigated and long-term data remain sparse. This observational study evaluates long-term effects of deep brain stimulation (DBS) of the globus pallidus internus (GPi) in patients with medically refractory TS., Methods: We retrospectively analyzed a cohort of seven TD patients with bilateral GPi-DBS. Involuntary movements, dystonia and disability were rated at long-term follow-up (LT-FU) after a mean of 122 ± 33.2 SD months (range 63-171 months) and compared to baseline (BL), short-term (ST-FU; mean 6 ± 2.0 SD months) and 4-year follow-up (4y-FU; mean 45 ± 12.3 SD months) using the Abnormal Involuntary Movement Scale (AIMS) and the Burke-Fahn-Marsden Dystonia Rating Scale (BFMDRS), respectively. Quality of life and mood were evaluated using the SF36 and Beck Depression Index (BDI) questionnaires, respectively., Results: At LT-FU patients had improved by 73% ± 14.2 SD in involuntary movements and 90% ± 1.0 SD in dystonia. Mood had improved significantly whereas quality of life remained unchanged compared to baseline. No serious long-lasting stimulation-related adverse events (AEs) were observed. Three patients of this cohort presented without active stimulation and ongoing symptom relief at long-term follow-up after 3-10 years of continuous DBS., Conclusion: Pallidal DBS is a safe and effective long-term TD treatment. Even more interesting, three of our patients could stop stimulation after several years of DBS without serious relapse. Larger studies need to explore the phenomenon of ongoing symptom relief after DBS cessation., (© 2022. The Author(s).)

Background: Hemidystonia (HD) is characterized by unilateral involuntary torsion movements and fixed postures of the limbs and face. It often develops after deleterious neuroplastic changes secondary to injuries to the brain. This condition usually responds poorly to medical treatment, and deep brain stimulation often yields unsatisfactory results. We propose this study based on encouraging results from case reports of patients with HD treated by ablative procedures in the subthalamic region., Objective: To compare the efficacy of stereotactic-guided radiofrequency lesioning of the subthalamic area vs available medical treatment in patients suffering from acquired HD., Methods: This is an open-label study in patients with secondary HD allocated according to their treatment choice, either surgical or medical treatment; both groups were followed for one year. Patients assigned in the surgical group underwent unilateral campotomy of Forel. The efficacy was assessed using the Unified Dystonia Rating Scale, Fahn-Marsden Dystonia Scale, Arm Dystonia Disability Scale, and SF-36 questionnaire scores., Results: Patients in the surgical group experienced significant improvement in the Unified Dystonia Rating Scale, Fahn-Marsden Dystonia Scale, and Arm Dystonia Disability Scale (39%, 35%, and 15%, respectively) 1 year after the surgery, with positive reflex in quality-of-life measures, such as bodily pain and role-emotional process. Patients kept on medical treatment did not experience significant changes during the follow-up. No infections were recorded, and no neurological adverse events were associated with either intervention., Conclusion: The unilateral stereotaxy-guided ablation of Forel H1 and H2 fields significantly improved in patients with HD compared with optimized clinical treatment., (Copyright © Congress of Neurological Surgeons 2022. All rights reserved.)

Deep brain stimulation (DBS) is a reversible treatment for chorea-acanthocytosis (ChAc). Its safety and efficacy remain elusive due to the low prevalence of ChAc. We aimed to investigate the safety and efficacy of DBS for ChAc by systematically reviewing literature through PubMed and EMBASE. Inclusion criteria were reports on the efficacy or safety of DBS for ChAc and English language articles, and exclusion criteria were other movement disorders, non-human subjects, and studies without original data. Most studies were published as case reports, and we therefore pooled these cases in one cohort. Twenty studies with 34 patients were included. The mean age of symptom onset was 29.3 years (range, 17-48). The median follow-up was 12 months (range, 2-84). Twenty-nine patients underwent GPi-DBS, two received STN-DBS, and one underwent Vop-DBS. Electrodes were implanted into the ventralis oralis complex of the thalamus and the pallidal in two patients. Symptoms seemed to be easier relieved in chorea (88.5%) and dystonia (76.9%) but dysarthria of most patients (85.7%) was no response after DBS. The Unified Huntington's Disease Rating Scale-Motor Score was used to assess the efficacy of DBS in 25 patients; the mean score decreased from 43.2 to 22.3 and the median improvement rate was 46.7%. Of 24 patients with data on adverse events, complications occurred in 9 patients (37.5%; mostly transient and mild events). DBS is a promising treatment for ChAc with satisfactory efficacy and safety based on the review. Pallidal and thalamic DBS have been applied in ChAc; GPi-DBS seems to be more widely used., (© 2022. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Microbial metabolites identified in animal models and human neurological diseases could be therapeutic targets.

Background: Further reports are required to describe the outcome of truncal dystonia treated by bilateral pallidal stimulation (globus pallidus interna deep brain stimulation [GPi-DBS]), owing to the small number of reports and clinical variability and complexity of truncal dystonia. Retrospectively, we report our experience of treating three patients with idiopathic generalized dystonia, with predominant mobile truncal dystonia by bilateral GPi-DBS., Methods: Three patients with idiopathic generalized dystonia underwent bilateral GPi-DBS. One patient had adult-onset dystonia, while two patients had childhood-onset dystonia. All patients had predominant mobile truncal dystonia of mixed abnormal postures (camptocormia and lateral tilt), while one patient had also truncal twist. Patients were assessed pre- and post-GPi-DBS using the Burke-Fahn-Marsden Dystonia Rating Scale (BFMDRS) and Dystonia Disability Scale (DDS)., Results: The three patients showed marked improvement of global (94.78%, 92.4% and 80.95%) and truncal BFMDRS (all abnormal postures) (87.5%, 93.75% and 87.5%) and DDS (95.84% and 50%), using high amplitude monopolar settings, with a dramatic improvement of the mobile component. Improvement was persistent for 1.5, 3 and 6 years., Conclusion: Bilateral GPi-DBS improves markedly the mobile truncal dystonia and associated abnormal postures in patients with adult and childhood-onset idiopathic generalized dystonia. Improvement was persistent for up to 6 years.

Dystonia is a prevalent, heterogeneous movement disorder characterized by involuntarily abnormal postures. Biomarkers of dystonia are notoriously lacking. Here, a biomarker is reported for histone lysine methyltransferase (KMT2B)-deficient dystonia, a leading subtype among the individually rare monogenic dystonias. It was derived by applying a support vector machine to an episignature of 113 DNA CpG sites, which, in blood cells, showed significant epigenome-wide association with KMT2B deficiency and at least 1× log-fold change of methylation. This classifier was accurate both when tested on the general population and on samples with various other deficiencies of the epigenetic machinery, thus allowing for definitive evaluation of variants of uncertain significance and identifying patients who may profit from deep brain stimulation, a highly successful treatment in KMT2B-deficient dystonia. Methylation was increased in KMT2B deficiency at all 113 CpG sites. The coefficients of variation of the normalized methylation levels at these sites also perfectly classified the samples with KMT2B-deficient dystonia. Moreover, the mean of the normalized methylation levels correlated well with the age at onset of dystonia (P = 0.003)-being lower in samples with late or incomplete penetrance-thus serving as a predictor of disease onset and severity. Similarly, it may also function in monitoring the recently envisioned treatment of KMT2B deficiency by inhibition of DNA methylation., (© The Author(s) (2021). Published by Oxford University Press on behalf of the Guarantors of Brain. All rights reserved. For permissions, please email: journals.permissions@oup.com.)

Dystonia and tremor frequently co-occur. In some cases, they have shared biological mechanisms, while in others dystonia and tremor are two comorbid conditions. The term "dystonic tremor" is used to describe tremor in those who have dystonia. Two mutually exclusive definitions of "dystonic tremor" were proposed. According to one definition, dystonic tremor is the tremor in the dystonic body part. An alternate definition of dystonic tremor entails irregular and jerky oscillations that have saw tooth appearance with or without overt dystonia. This paper outlines the differences in two definitions of dystonic tremor and identifies their limitations. Given the diverse views defining "dystonic tremor", this paper will use the term "tremor in dystonia". In addition, we will outline different ways to separate the subtypes of tremor in dystonia. Then we will discuss pathophysiological mechanisms derived from the objective measures and single neuron physiology analyses of tremor in dystonia. This article is part of the Special Issue "Tremor" edited by Daniel D. Truong, Mark Hallett, and Aasef Shaikh., (Copyright © 2022. Published by Elsevier B.V.)

Deep brain stimulation (DBS) is an effective treatment of several types of neurological conditions, including Parkinson's disease, essential tremor, dystonia, and epilepsy. Despite technological progress in the past 10 years, the number of studies reporting side effects of DBS has increased, mainly due to hardware failures. This review investigated studies published between 2017 and 2021 to identify the prevalence of distinct types of hardware failures related to DBS. In total, fifteen studies were selected for the estimate of the prevalence of five distinct types of hardware failures: high impedance, fracture or failure of the lead or other parts of the implant, skin erosion and infection, lead malposition or migration, and implantable pulse generator (IPG) malfunction. The quality evaluation of the studies suggests a need to report results including populations from distinct regions of the world so that results can be generalized. The objective analysis of the prevalence of hardware failures showed that skin erosion and infection presented the highest prevalence in relation to other hardware failures. Despite the sophistication of the surgical technique of DBS over time, there is a considerable complication rate, about 7 per 100 individuals ([Formula: see text], in which CI is the confidence interval). Future research can also include correlation analysis with the aim of understanding the correlation between distinct hardware failures and variables such as gender, type of disorder, and age., (© 2021. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Background: Adductor laryngeal dystonia (ADLD) is a substantially debilitating focal progressive neurological voice disorder. Current standard of care is symptomatic treatment with repeated injections of botulinum toxin into specific intrinsic laryngeal muscles with extremely variable and temporary benefits. We report the use of bilateral deep brain stimulation (DBS) of globus pallidus (GPi) for long-term improvement of ADLD voice symptoms., Objective: To investigate the effects of bilateral DBS of the GPi and ventral intermediate nucleus (VIM) of the thalamus on vocal function in 2 patients with ADLD associated with voice and hand tremor., Methods: Blinded objective and quantitative analyses of voice were conducted before and after treatment in 2 female patients (70 and 69 years). Paired t-tests were conducted to compare voice measurements pre-GPi and post-GPi and VIM-DBS. A 2-way analysis of variance was conducted to determine the interaction between target (GPi/VIM) and time (pre/post) for each voice measure., Results: Although the follow-up period differed between patients, the GPi-DBS implanted patient had notable improvement in vowel voicing (%), extent of tremor intensity (%), and overall speech intelligibility (%), compared with preoperative status. GPi-DBS also resulted in significant improvement in cepstral peak prominence (dB). VIM-DBS resulted in a significantly greater change in the tremor rate (Hz)., Conclusion: Changes in phonatory function provide preliminary support for the use of bilateral GPi-DBS for treatment of ADLD and bilateral VIM-DBS for vocal tremor predominant ADLD. Future studies with larger sample sizes and standardized follow-up periods are needed to better assess the role of DBS for ADLD., (Copyright © Congress of Neurological Surgeons 2022. All rights reserved.)

Background: Pallidal Deep Brain Stimulation (DBS) is an established treatment option for isolated, inherited or idiopathic dystonia, however data on its safety and efficacy in other forms of dystonia are more limited., Objectives: Retrospective analysis of motor and non-motor outcomes in pediatric onset refractory dystonia due to static or progressive brain disorders in a cohort of patients with a DBS treatment duration ≥12 months., Methods: Multidisciplinary assessments including standardised scales/tests of motor function, pain, quality of life, cognition and language were carried out before implantation and longitudinally afterwards., Results: 9 patients were included, 7 had cerebral palsy. Mean age at implantation was 209 months ± 156, mean treatment duration 84 ± 37 months. DBS was well tolerated and positively affected both motor and non-motor functions. In particular, statistically significant improvements were documented in Burke-Fahn-Marsden Scale scores (- 19.9% p 0.01031) at 12 months and in long-term quality of life (+28.6%, p 0.0292)., Conclusions: DBS may be a useful treatment option in generalized dystonia associated with brain pathology. Even when the motor benefits are limited, improvements in quality of life and non-motor functions, or the possible prevention of serious dystonia-related complications, may have a significant impact on overall clinical status., (© 2022 Published by Elsevier Ltd on behalf of European Paediatric Neurology Society.)

Cerebral palsy (CP) is the most common cause of motor disability in children. The largest group of children with CP present with spasticity. Dystonia is estimated to be present in approximately 15% of children with CP, referred to as dyskinetic CP. Still, dystonia in CP remains underdiagnosed. Dystonia and spasticity can occur together in a subgroup of children with CP as well. Dystonia is characterized by fluctuating hypertonia and involuntary movement and postures. Dystonia in children with CP can interfere with motor function, caregiving and comfort. It is important to recognize dystonia in children with CP as specific treatment is indicated. In this paper we describe three cases of children with dystonia in CP and we review the pharmacological treatment options for dystonia in CP and the surgical options including intrathecal baclofen pump and deep brain stimulation.

Background: Japanese encephalitis (JE) is a potentially fatal viral infection with a wide range of manifestations and can also present with a variety of movement disorders (MD) including dystonia. Dystonic features in JE are uncommon. Here, we have tried to summarize the clinical features and management of dystonia among JE patients with a comprehensive literature search., Methods: Various databases, including PubMed, Embase, and Google Scholar, were searched against the predefined criteria using suitable keywords combination and boolean operations. Relevant information from observational and case studies was extracted according to the author, dystonic features, radiological changes in the brain scans, treatment options, and outcome wherever provided., Result: We identified 19 studies with a total of 1547 JE patients, the diagnosis of which was confirmed by IgM detection in serum and/or cerebrospinal fluid in the majority of the patients (88.62%). 234 (15.13%) of JE patients had dystonia with several types of focal dystonia being present in 131 (55.98%) either alone or in combination. Neuroimaging showed predominant involvement of thalami, basal ganglia, and brainstem. Oral medications including anticholinergics, GABA agonists, and benzodiazepines followed by botulinum toxin were the most common treatment modalities., Conclusion: Dystonia can be a disabling consequence of JE, and various available medical therapies can significantly improve the quality of life. Owing to insufficient studies on the assessment of dystonia associated with JE, longitudinal studies with a larger number of patients are warranted to further clarify the clinical course, treatment, and outcome of dystonia., (© 2022 The Authors. Brain and Behavior published by Wiley Periodicals LLC.)

This study evaluated the long-term efficacy of globus pallidus internus (GPi) deep brain stimulation (DBS) in the treatment of craniofacial dystonia (Meige syndrome) and investigated the correlation between the volume of tissue activated (VTA) in the GPi and each subregion and movement score improvement. We retrospectively analyzed the clinical data of 13 patients with drug-refractory Meige syndrome who were treated with GPi DBS. The pre- and postoperative Burke-Fahn-Marsden Dystonia Rating Scale (BFMDRS) scores were compared. The relationships between the preoperative baseline variables and improvement in the BFMDRS-Movement (BFMDRS-M) score were analyzed. LEAD-DBS software was used for the three-dimensional reconstruction of the GPi and implanted electrodes. The correlations between the GPi-VTA and score improvement were analyzed. The average follow-up period was 36.6 ± 11.0 months (18-55 months). At 3 months after the stimulation and the final follow-up visit, the improvements in the BFMDRS-M score were 58.2 and 54.6%, and the improvements in the BFMDRS-Disability (BFMDRS-D) score were 53.6 and 51.7%, respectively. At the final follow-up visit, the improvements in the BFMDRS-M scores of the eye, mouth, and speech/swallowing were significant (P < 0.001). Age was an independent predictor of improvement in the BFMDRS-M score after DBS (P = 0.005). A decrease in the BFMDRS-M score was significantly positively correlated with the GPi-VTA (r = 0.757, P = 0.003). GPi DBS is an effective method for treating drug-refractory Meige syndrome. LEAD-DBS software can be used as an effective aid for visualization programming after DBS., (© 2021. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Purpose: Globus pallidus pars interna (GPi) has become an established target for deep brain stimulation (DBS) in dystonia. Previous studies suggest that targeting the ventralis oralis (Vo) complex nucleus improves dystonic tremor or even focal dystonia. Research has also demonstrated that multi-target DBS shows some benefits over single target DBS. In this study, we reviewed patients who had undergone unilateral DBS targeting the GPi and Vo., Materials and Methods: Five patients diagnosed with medically refractory upper extremity dystonia (focal or segmental) underwent DBS. Two DBS electrodes each were inserted unilaterally targeting the ipsilateral GPi and Vo. Clinical outcomes were evaluated using the Burke-Fahn-Marsden Dystonia Rating Scale (BFMDRS) and Disability Rating Scale., Results: BFMDRS scores decreased by 55% at 1-month, 56% at 3-month, 59% at 6-month, and 64% at 12-month follow up. Disability Rating Scale scores decreased 41% at 1-month, 47% at 3-month, 50% at 6-month, and 60% at 12-month follow up. At 1 month after surgery, stimulating both targets improved clinical scores better than targeting GPi or Vo alone., Conclusion: Unilateral thalamic and pallidal dual electrode DBS may be as effective or even superior to DBS of a single target for dystonia. Although the number of patients was small, our results reflected favorable clinical outcomes., Competing Interests: The authors have no potential conflicts of interest to disclose., (© Copyright: Yonsei University College of Medicine 2022.)

Background and Objective: Deep brain stimulation (DBS) is used for treating dystonia, commonly targeting the subthalamic nucleus (STN). Optimal stimulation parameters are required to achieve satisfying results. However, recommended parameters for STN-DBS remain to be identified. In this review, we aimed to assess the optimal stimulation parameters by analyzing previously published STN-DBS data of patients with dystonia., Methods: We examined the STN-DBS stimulation parameters used in studies on dystonia selected on the PubMed/Medline database., Results: Of the 86 publications retrieved from the PubMed/Medline database, we included 24, which consisted of data from 94 patients and 160 electrodes. Overall, the following average stimulation parameters were observed: amplitude, 2.59 ± 0.67 V; pulse width, 83.87 ± 34.70 μs; frequency, 142.08 ± 37.81 Hz. The average improvement rate was 64.72 ± 24.74%. The improvement rate and stimulation parameters were linearly dependent. The average improvement rate increased by 3.58% at each 10-Hz increase in frequency. In focal and segmental dystonia, the improvement rate and stimulation parameters were linearly dependent. The improvement rate increased by 6.06% and decreased by 2.14% at each 10-Hz increase in frequency and pulse width, respectively. Seventeen publications (83 patients) mentioned stimulation-related adverse effects, including dyskinesia (17), depression (8), transient dysarthria (5), weight gain (4), transient dysphasia (3), transient paresthesia (2), and sustained hyperkinesia (2)., Conclusions: The optimal stimulation parameter for STN-DBS varies across patients. Our findings may be useful for DBS programming based on the specific dystonia subtypes, especially for patients with focal and segmental dystonia., (© 2021. Springer-Verlag GmbH, DE part of Springer Nature.)

Sex and gender-based differences in epidemiology, clinical features and therapeutical responses are emerging in several movement disorders, even though they are still not widely recognized. In this chapter, we summarize the most relevant evidence concerning these differences in Parkinson's disease, essential tremor, dystonia and chorea. Indeed, both sex-related biological (hormonal levels fluctuations) and gender-related variables (socio-cultural and environmental factors) may differently impact symptoms manifestation and severity, phenotype and disease progression of movement disorders on men and women. Moreover, sex differences in treatment responses should be taken into account in any therapeutical planning. Physicians need to be aware of these major differences between men and women that will eventually have a major impact on better tailoring prevention, treatment, or even delaying progression of the most common movement disorders., (Copyright © 2022 Elsevier Inc. All rights reserved.)

Dystonia is a hyperkinetic movement disorder associated with loss of inhibition, abnormal plasticity, dysfunctional sensorimotor integration, and brain oscillatory dysfunctions at cortical and subcortical levels of the central nervous system. Hence, dystonia is considered a network disorder that can, in many cases, be efficiently treated by pallidal deep brain stimulation (DBS). Abnormal oscillatory activity has been identified across the motor circuit of patients with dystonia. Increased low frequency (LF) synchronization in the internal pallidum is the most prominent abnormality. LF oscillations have been associated with the severity of dystonic motor symptoms; they are suppressed by DBS and localized to the clinically most effective stimulation site. Although the origin of these pathologic changes in brain activity needs further clarifications, their characterization will help in adjusting DBS parameters for successful clinical outcome., (Copyright © 2022 Elsevier B.V. All rights reserved.)

We review the findings for motor cortical excitability, plasticity and evoked potentials in dystonia. Plasticity can be induced and assessed in cortical areas by non-invasive brain stimulation techniques such as transcranial magnetic stimulation (TMS) and the invasive technique of deep brain stimulation (DBS), which allows access to deep brain structures. Single-pulse TMS measures have been widely studied in dystonia and consistently showed reduced silent period duration. Paired pulse TMS measures showed reduced short and long interval intracortical inhibition, interhemispheric inhibition, long-latency afferent inhibition and increased intracortical facilitation in dystonia. Repetitive transcranial magnetic stimulation (rTMS) of the premotor cortex improved handwriting with prolongation of the silent period in focal hand dystonia patients. Continuous theta-burst stimulation (cTBS) of the cerebellum or cTBS of the dorsal premotor cortex improved dystonia in some studies. Plasticity induction protocols in dystonia demonstrated excessive motor cortical plasticity with the reduction in cortico-motor topographic specificity. Bilateral DBS of the globus pallidus internus (GPi) improves dystonia, associated pain and functional disability. Local field potentials recordings in dystonia patients suggested that there is increased power in the low-frequency band (4-12 Hz) in the GPi. Cortical evoked potentials at peak latencies of 10 and 25 ms can be recorded with GPi stimulation in dystonia. Plasticity induction protocols based on the principles of spike timing dependent plasticity that involved repeated pairing of GPi-DBS and motor cortical TMS at latencies of cortical evoked potentials induced motor cortical plasticity. These studies expanded our knowledge of the pathophysiology of dystonia and how cortical excitability and plasticity are altered with different treatments such as DBS., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2021 European Paediatric Neurology Society. Published by Elsevier Ltd. All rights reserved.)

Background: Task-specific dystonia (TSD) is a form of focal dystonia that occurs in the context of the performance of selective, highly skilled, often repetitive, motor activity. TSD may be apparent during certain tasks such as writing, playing musical instruments, or other activities requiring fine motor control, but may also occur during certain sports, and maybe detrimental to professional athletes' careers. Therefore, sports physicians and movement disorder neurologists need to be aware of the presentation and phenomenology of sports-related dystonia (SRD), the topic of this review., Methods: A broad PubMed search using a wide range of keywords and combinations was done in October 2021 to identify suitable articles for this review., Results: Most of the publications are on yips in golfers and on runners' dystonia. Other sports in which SRD has been reported are ice skating, tennis, table tennis, pistol shooting, petanque, baseball, and billiards., Discussion: Yips, which may affect up to half of the golfers and rarely athletes in other sports (e.g., baseball, cricket, basketball, speed skating, gymnastics) seems to be a multi-factorial form of TSD that is particularly troublesome in highly skilled professional golfers. Runners' dystonia, affecting the foot, leg, and hip (in decreasing order), may evolve into more generalized and less specific dystonia. The pathophysiologic mechanisms of SRD are not well understood. Botulinum toxin has been reported to alleviate dystonia in golfers', runners', and other forms of SRD. Future studies should utilize neurophysiologic, imaging, and other techniques to elucidate mechanisms of this underrecognized group of movement disorders., Competing Interests: The authors have no competing interests to declare., (Copyright: © 2021 The Author(s).)

Objective: Deep brain stimulation (DBS) is a frequently applied therapy in primary dystonia. For secondary dystonia, the effects can be less favorable. We share our long-term findings in 9 patients with severe secondary dystonia and discuss these findings in the light of the literature., Methods: Patients who had undergone globus pallidus internus (GPi)-DBS for secondary dystonia were included. Burke-Fahn-Marsden Dystonia Rating Scale (BFMDRS) scores, clinical improvement rates, follow-up periods, stimulation parameters and the need for internal pulse generator replacements were analyzed. The PubMed and Google Scholar databases were searched for articles describing GPi-DBS and subthalamic nucleus (STN)-DBS only for secondary dystonia cases. Keywords were "dystonia," "deep brain stimulation," "GPi," "dystonia," "deep brain stimulation," and "STN.", Results: A total of 9 secondary dystonia patients (5 male, 4 female) had undergone GPi-DBS with microelectrode recording in our units. The mean follow-up period was 29 months. The average BFMDRS score was 58.2 before the surgery, whereas the mean value was 36.5 at the last follow-up of the patients (mean improvement, 39%; minimum, 9%; maximum, 63%). In the literature review, we identified 264 GPi-DBS cases (mean follow-up, 19 months) in 72 different articles about secondary dystonia. The mean BFMDRS improvement rate was 52%. In 146 secondary dystonia cases, reported in 19 articles, STN-DBS was performed. The average follow-up period was 20 months and the improvement in BFMDRS score was 66%., Conclusions: Although GPi-DBS has favorable long-term efficacy and safety in the treatment of patients with secondary dystonia, STN seems a promising target for stimulation in patients with secondary dystonia. Further studies including a large number of patients, longer follow-up periods, and more homogenous patients are necessary to establish the optimal target for DBS in the management of secondary dystonias., (Copyright © 2021 Elsevier Inc. All rights reserved.)

Context: Movement disorders represent a common presentation in pediatrics and are often a source of clinical and diagnostic dilemmas. In this review, we provide an overview of common causes along with simplified clinical approach and management options for major movement disorders., Sources: This narrative review is based on contemporary evidence and personal experience. Medline was searched for recent advances, current understanding and consensus on classification, clinical features, diagnosis and treatment., Results: Movement disorders are classified as hyperkinetic and hypokinetic disorders, the latter being rare in childhood. The hyperkinetic disorders include dystonia, chorea, athetosis, tics and tremor, stereotypies, myoclonus, startle syndromes and functional disorders. Some movement disorders can be benign and developmental. A large proportion of conditions are genetic in origin with a guarded prognosis. Some of the conditions may be post-infectious, immune-mediated or drug induced. Multiple types of movement disorders are present in many conditions. The age at onset, type and distribution of abnormal movements and presence of associated neurological and systemic features help in narrowing the differential diagnosis. The pharmacotherapy of movement disorders is complex and evolving., Conclusion: A synopsis of movement disorders presenting in pediatric age has been provided, incorporating the latest evidence. A simplified approach for clinical diagnosis has been developed for dystonia and chorea.

Aim: To update a systematic review of evidence published up to December 2015 for pharmacological/neurosurgical interventions among individuals with cerebral palsy (CP) and dystonia., Method: Searches were updated (January 2016 to May 2020) for oral baclofen, trihexyphenidyl, benzodiazepines, clonidine, gabapentin, levodopa, botulinum neurotoxin (BoNT), intrathecal baclofen (ITB), and deep brain stimulation (DBS), and from database inception for medical cannabis. Eligible studies included at least five individuals with CP and dystonia and reported on dystonia, goal achievement, motor function, pain/comfort, ease of caregiving, quality of life (QoL), or adverse events. Evidence certainty was evaluated using GRADE., Results: Nineteen new studies met inclusion criteria (two trihexyphenidyl, one clonidine, two BoNT, nine ITB, six DBS), giving a total of 46 studies (four randomized, 42 non-randomized) comprising 915 participants when combined with those from the original systematic review. Very low certainty evidence supported improved dystonia (clonidine, ITB, DBS) and goal achievement (clonidine, BoNT, ITB, DBS). Low to very low certainty evidence supported improved motor function (DBS), pain/comfort (clonidine, BoNT, ITB, DBS), ease of caregiving (clonidine, BoNT, ITB), and QoL (ITB, DBS). Trihexyphenidyl, clonidine, BoNT, ITB, and DBS may increase adverse events. No studies were identified for benzodiazepines, gabapentin, oral baclofen, and medical cannabis., Interpretation: Evidence evaluating the use of pharmacological and neurosurgical management options for individuals with CP and dystonia is limited to between low and very low certainty. What this paper adds Meta-analysis suggests that intrathecal baclofen (ITB) and deep brain stimulation (DBS) may improve dystonia and pain. Meta-analysis suggests that DBS may improve motor function. Clonidine, botulinum neurotoxin, ITB, and DBS may improve achievement of individualized goals. ITB and DBS may improve quality of life. No direct evidence is available for oral baclofen, benzodiazepines, gabapentin, or medical cannabis., (© 2021 The Authors. Developmental Medicine & Child Neurology published by John Wiley & Sons Ltd on behalf of Mac Keith Press.)

Intraoperative neurophysiological information could increase accuracy of surgical deep brain stimulation (DBS) lead placement. Subsequently, DBS therapy could be optimized by specifically targeting pathological activity. In Parkinson's disease, local field potentials (LFPs) excessively synchronized in the beta band (13-35 Hz) correlate with akinetic-rigid symptoms and their response to DBS therapy, particularly low beta band suppression (13-20 Hz) and high frequency gamma facilitation (35-250 Hz). In dystonia, LFPs abnormally synchronize in the theta/alpha (4-13 Hz), beta and gamma (60-90 Hz) bands. Phasic dystonic symptoms and their response to DBS correlate with changes in theta/alpha synchronization. In essential tremor, LFPs excessively synchronize in the theta/alpha and beta bands. Adaptive DBS systems will individualize pathological characteristics of neurophysiological signals to automatically deliver therapeutic DBS pulses of specific spatial and temporal parameters.

There is no available data on the journey of dystonia patients once referred to a tertiary center to undergo deep brain stimulation (DBS). We hypothesized that some patients might be incorrectly diagnosed while others might decline the procedure or experience significant benefit with switching to a different botulinum neurotoxin (BoNT). This is a single-center, retrospective study of dystonia patients who were referred to the DBS program between January 2014 and December 2018. We collected data on the surgical decision as well as factors influencing this decision. Sixty-seven patients were included (30 males, mean age: 48.3 ± 20.1 years, disease duration: 16.9 ± 15.3 years). Thirty-three (49%) patients underwent DBS. Four (6%) patients were awaiting the procedure while the remaining 30 patients (45%) did not undergo DBS. Reasons for DBS decline were patient refusal (17, 53%), functional dystonia (6, 20%), and successful use of AbobotulinumtoxinA (3, 10%) in patients who had failed other BoNTs. Our study highlights the importance of structured patient education to increase acceptance of DBS, as well as careful patient evaluation, particularly with respect to functional dystonia. Finally, changing BoNT formulation might be beneficial in some patients.

Stereotactic and functional neurosurgery(deep brain stimulation[DBS]and radiofrequency coagulation)is an established method of treatment for patients with Parkinson's disease, tremor, and/or dystonia. The surgery involves many pitfalls and is similar to other surgeries, requiring experience and skills. Here, we have discussed three categories of DBS-related complications, including surgical procedure-related and device-related complications, and stimulation-induced side effects. In addition, we have discussed the prevention and coping methods, including those not listed in the guidelines for stereotactic and functional neurosurgery.

Background: Childhood-onset hyperkinetic movement disorders (HMD), including dystonia are notoriously difficult to treat and there are limited studies showing successful medical, surgical or non-pharmacological interventions., Methods: This prospective study used grouped data (n = 22) from two studies of the Cognitive Orientation to daily Occupational Performance (CO-OP) Approach for patient-selected goals. Eligibility included aged 6-21 years, deep brain stimulation in place, with manual ability classification system level I-IV. Outcome was assessed on a range of patient-reported and clinician-rated measures across the International Classification of Function at end-treatment (10 weekly sessions) (series 1 and 2) and 3-month follow-up (series 1). Feasibility of outcomes to be used in a full trial were explored., Findings: Nineteen participants completed the intervention and were included in the analysis. Of the primary outcome measures, the self-reported Canadian Occupational Performance Measure showed improvement in goal performance (mean change 4.08, 95% CI [3.37,4.79] post-; 4.18 [5.10,5.26] follow-up), and satisfaction (4.03 [3.04,5.03) post-; 4.44 [3.07,5.82] follow-up]. The Assessment of Motor and Process Skills showed improved motor score (0.52 [0.01,1.03] at follow-up only, while the process score did not change. Objective blind-rated pooled data using the Performance Quality Rating Scale-individualized indicated significant change for trained goals (3.79 [3.37,4.21] post-; (4.01,5.10) follow-up] and untrained goals (1.90 [1.24,2.55] post 1.91 [0.23,3.60] follow-up]. Motor impairment assessed by the Burke-Fahn Motor Disability Rating Scale was unchanged (-3.26 [-6.62,0.09] post-; -1.11 [-8.05,5.82] follow-up). Improvement was also observed in self-efficacy (0.97 [0.47,1.47] post-; 1.37 [1.91-0.83] follow-up) and Quality of Life (0.12 [0.03-0.22] follow-up). Goal improvement; self-efficacy and quality of life captured significant change post-intervention. This improvement was shown despite no change on impairment-related measures and were shown to be feasible measures to use in a larger study of CO-OP for this population., Competing Interests: Declaration of competing interest J-PL has received unrestricted educational support for instructional courses and consultancy fees from Medtronic Ltd. The rest of the authors have nothing to disclose., (Crown Copyright © 2021. Published by Elsevier Ltd. All rights reserved.)

Objective: The efficacy and safety of deep brain stimulation (DBS) under general anesthesia for the treatment of dystonia have not yet been confirmed with high level of evidence. This meta-analysis with pooled individual patient data aims to assess the clinical outcomes and identify the potential prognostic factors of dystonia patients who underwent general anesthesia DBS., Methods: We searched PubMed, Web of Science, and Embase for articles describing patients with dystonia who underwent asleep DBS and had individual Burke-Fahn-Marsden Dystonia Rating Scale (BFMDRS) scores. The relative improvement in BFMDRS scores was considered the primary outcome. Pearson correlation analyses and multivariate linear regression analysis were conducted to explore the prognostic factors., Results: A total of 34 studies involving 341 patients were included. The mean postoperative improvement in BFMDRS-M (BFMDRS movement subscale) and BFMDRS-D (BFMDRS disability subscale) scores were 58.6±36.2% and 48.5±38.7% at the last follow-up visit, respectively, with a mean follow-up time of 22.4±27.6 months. Age at surgery and disease duration showed a negative correlation with the percent improvement of BFMDRS-M (%) at the last visit (r=-0.134, P=0.013; r=-0.165, P=0.006). In the stepwise multivariate regression, only disease duration remained a relevant factor. Additionally, the adverse events were acceptable., Conclusion: General anesthesia DBS is a safe, effective, and feasible option for dystonia patients in the long term. Shorter disease duration predicts better clinical outcomes.

Dystonia is one of the most common pediatric movement disorders and can have a profound impact on the lives of children and their caregivers. Response to pharmacologic treatment is often unsatisfactory. Deep brain stimulation (DBS) has emerged as a promising treatment option for children with medically refractory dystonia. In this review we highlight the relevant literature related to DBS for pediatric dystonia, with emphasis on the background, indications, prognostic factors, challenges, and future directions of pediatric DBS., (Copyright © 2021 Elsevier Inc. All rights reserved.)

Dystonia is a movement disorder characterized by sustained or intermittent muscle contractions causing abnormal, often repetitive, movements or postures. Currently, dystonia is defined as a network disorder involving the basal ganglia, cerebellum, thalamus, and sensorimotor cortex. Considering that it is refractory to medical therapy, functional neurosurgery is indispensable in the treatment strategy for dystonia. Functional neurosurgery may improve dystonic symptoms by suppressing abnormal neuronal activity in the motor loop network. Deep brain stimulation(DBS)of the globus pallidus internus(GPi)is a useful surgical treatment for genetically defined and primary dystonia involving the axial musculature. Thalamic ventral oral(Vo)nucleus surgery is recommended for cases of peripheral dystonia, such as writer's cramp and other occupational types of dystonia. However, pallidal DBS is less effective in cases of secondary dystonia, with the exception of tardive dystonia. Recent studies have reevaluated that ablation surgery is the last-resort treatment when DBS must be discontinued for certain conditions. Magnetic resonance-guided focused ultrasound(MRgFUS), a novel, incision-free, ablation technique, is currently used for the treatment of focal hand dystonia.

Pallidal deep brain stimulation (DBS) is an important option for patients with severe dystonias, which are thought to arise from a disturbance in striatal control of the globus pallidus internus (GPi). The mechanisms of GPi-DBS are far from understood. Although a disturbance of striatal function is thought to play a key role in dystonia, the effects of DBS on cortico-striatal function are unknown. We hypothesised that DBS, via axonal backfiring, or indirectly via thalamic and cortical coupling, alters striatal function. We tested this hypothesis in the dt sz hamster, an animal model of inherited generalised, paroxysmal dystonia. Hamsters (dystonic and non-dystonic controls) were bilaterally implanted with stimulation electrodes in the GPi. DBS (130 Hz), and sham DBS, were performed in unanaesthetised animals for 3 h. Synaptic cortico-striatal field potentials, as well as miniature excitatory postsynaptic currents (mEPSC) and firing properties of medium spiny striatal neurones were recorded in brain slice preparations obtained immediately after EPN-DBS. The main findings were as follows: a. DBS increased cortico-striatal evoked responses in healthy, but not in dystonic tissue. b. Commensurate with this, DBS increased inhibitory control of these evoked responses in dystonic, and decreased inhibitory control in healthy tissue. c. Further, DBS reduced mEPSC frequency strongly in dystonic, and less prominently in healthy tissue, showing that also a modulation of presynaptic mechanisms is likely involved. d. Cellular properties of medium-spiny neurones remained unchanged. We conclude that DBS leads to dampening of cortico-striatal communication, and restores intrastriatal inhibitory tone., (Copyright © 2021 The Author(s). Published by Elsevier Inc. All rights reserved.)

Background: Unlike motor symptoms, the effects of deep brain stimulation (DBS) on non-motor symptoms associated with dystonia remain unknown., Methods: The objective of this study was to assess the effects of DBS on evoked experimental pain and cutaneous sensory thresholds in a crossover, double-blind on/off study and compare these results with those of healthy volunteers (HV)., Results: Sixteen patients with idiopathic dystonia (39.9 ± 13 years old, n = 14 generalized) with DBS of the globus pallidus internus underwent a battery of quantitative sensory testing and assessment using a pain top-down modulation system (conditioned pain modulation, CPM). Results for the more and less dystonic body regions were compared in on and off stimulation. The patients' results were compared to age- and sex-matched HV. Descending pain modulation CPM responses in dystonic patients (on-DBS, 11.8 ± 40.7; off-DBS, 1.8 ± 22.1) was abnormally low (defective) compared to HV (-15.6 ± 23.5, respectively p = .006 and p = .042). Cold pain threshold and cold hyperalgesia were 54.8% and 95.7% higher in dystonic patients compared to HV. On-DBS CPM correlated with higher Burke-Fahn-Marsden disability score (r = 0.598; p = .014). While sensory and pain thresholds were not affected by DBS on/off condition, pain modulation was abnormal in dystonic patients and tended to be aggravated by DBS., Conclusion: The analgesic effects after DBS do not seem to depend on short-duration changes in cutaneous sensory thresholds in dystonic patients and may be related to changes in the central processing of nociceptive inputs., (© 2021 European Pain Federation - EFIC®.)

Deep brain stimulation(DBS)is an effective therapy for conditions involving drug-resistant involuntary movements, such as Parkinson's disease, tremor, and dystonia. Programming of DBS, as well as strict surgical indications, appropriate target selection, and accurate electrode placement, is one of the most important factors in the success of DBS. To obtain effective stimulation for a long period, it is important to expand the therapeutic window and reduce side effects. Recent advances in DBS devices have dramatically expanded the variety of stimulus settings. While the indication criteria of DBS and surgical techniques have been established, the details of the programming algorithm are not yet unified. In this paper, we describe the features of each device, basic programming methods, management of DBS-related side effects, and advanced stimulus methods.