Meige Syndrome Research Articles

Subthalamic Nucleus Deep Brain Stimulation for Meige Syndrome: Long-Term Outcomes and Analysis of Prognostic Factors.

The aim of this study was to explore the impacts of subthalamic nucleus deep brain stimulation (STN-DBS) on both motor and nonmotor symptoms in individuals with Meige syndrome, as well as further investigates prognostic factors for long-term postoperative outcomes. We retrospectively reviewed a consecutive cohort of patients with intractable Meige syndrome who underwent STN-DBS at our center from January 2016 to July 2023. Motor function, quality of life, neuropsychological status, and mood state were evaluated with standardized scales at baseline and every 3 to 6 months thereafter. Univariate and multivariate linear regression analyses were used to determine independent risk factors that affect long-term motor function after STN-DBS. Fifty-five patients were ultimately analyzed with a mean follow-up of 62.1 ± 25.7 months. At the final postoperative assessment, movement and disability scores of the Burke-Fahn-Marsden Dystonia Rating Scale demonstrated improvements of 61% (P < .001) and 57% (P < .001), respectively. Postoperative scores on the 36-item Short-Form General Health Survey showed significant improvement from baseline. Global cognitive function and neuropsychological status remained stable during continuous neurostimulation. Multivariate linear regression analysis revealed that longer disease duration (standardized β coefficient = -0.294, 95% CI -0.039 to -0.007, P = .006), older age at surgery (standardized β coefficient = -0.382, 95% CI -0.014 to -0.004, P = .001), and smaller volume of tissue activated within the sensorimotor subregion of STN (standardized β coefficient = 0.309, 95% CI 0.001-0.004, P = .004) were independently correlated with poorer long-term motor performance. Bilateral STN-DBS is an effective, safe, and promising treatment option for Meige syndrome, which can improve motor function and quality of life without cognitive and mood side effects. Early diagnosis, prompt intervention, and accurate lead placement in the dorsolateral STN are crucial to optimize long-term therapeutic outcomes.

Acupuncture for Meige syndrome: A case report

IntroductionMeige syndrome (MS) is a cranial dystonia disorder characterized by blepharospasm and oromandibular dystonia. Current treatments include botulinum toxin therapy, oral medications, and surgical interventions. Here, we present a case that the patient's symptoms improved significantly after treatment with acupuncture. Case descriptionA 72-year-old woman came to our acupuncture clinic with eyelid twitching and jaw muscle tension. She described being diagnosed with MS two years ago due to the same symptoms, and her symptoms gradually worsened over the past six months. After 4 weeks of acupuncture treatment, the patient's MS symptoms improved significantly. ConclusionAcupuncture may be a potentially salvage treatment option for MS.

Deep brain stimulation and pallidotomy in primary Meige syndrome: a prospective cohort study.

Primary Meige syndrome (PMS) is a rare form of dystonia, and comparative analysis of globus pallidus internal deep brain stimulation (GPi-DBS), subthalamic nucleus deep brain stimulation (STN-DBS), and pallidotomy has been lacking. This study aims to compare the efficacy, safety, and psychiatric features of GPi-DBS, STN-DBS, and pallidotomy in patients with PMS. This prospective cohort study was divided into three groups: GPi-DBS, STN-DBS, and pallidotomy. Clinical assessments, including motor and non-motor domains, were evaluated at baseline and at 1year and 3years after neurostimulation/surgery. Ninety-eight patients were recruited: 46 patients received GPi-DBS, 34 received STN-DBS, and 18 underwent pallidotomy. In the GPi-DBS group, the movement score of the Burke-Fahn-Marsden Dystonia Rating Scale (BFMDRS) improved from a mean (SE) of 13.8 (1.0) before surgery to 5.0 (0.7) (95% CI, -10.5 to -7.1; P < 0.001) at 3years. Similarly, in the STN-DBS group, the mean (SE) score improved from 13.2 (0.8) to 3.5 (0.5) (95% CI, -10.3 to -8.1; P < 0.001) at 3years, and in the pallidotomy group, it improved from 14.9 (1.3) to 6.0 (1.1) (95% CI, -11.3 to -6.5; P < 0.001) at 3years. They were comparable therapeutic approaches for PMS that can improve motor function and quality of life without non-motor side effects. DBS and pallidotomy are safe and effective treatments for PMS, and an in-depth exploration of non-motor symptoms may be a new entry point for gaining a comprehensive understanding of the pathophysiology.

Computed tomography navigation radiofrequency ablation for Meige's syndrome: A game-changer in treatment

BackgroundMeige's syndrome severely impacts quality of life. Current treatments struggle to balance cost, risk, and effectiveness. MethodsPatients with blepharospasm were treated with facial nerves partial radiofrequency ablation guided by CT. Treatment efficacy, complications, and recurrences were evaluated during follow-up. Results116 facial nerves in 58 patients with Meige's syndrome were treated using CT guidance. The average temperature at the end of radiofrequency treatment was 77.93 ± 9.8 °C, and the procedure lasted an average of 30.79 ± 7.69 min. Spasms stopped after treatment, but mild facial paralysis remained. Follow-ups ranging from 12 to 57 months showed that facial paralysis improved in an average of 3.12 ± 0.94 months. Nine patients had unilateral recurrence within 6–13 months, and three had bilateral recurrence at 14, 18, and 22 months. ConclusionsPartial radiofrequency ablation of the facial nerve through percutaneous access to the bilateral stylomastoid foramen using CT navigation is an effective, safe, promising treatment for blepharospasm in Meige's syndrome patients.

Unilateral Stereotactic Radiofrequency Lesioning as a Surgical Treatment Option for Meige Syndrome.

Background Meige syndrome is a segmental dystonia affecting the head and neck, with bilateral blepharospasm as the primary symptom. First-line treatment typically involves Botox injections. For cases resistant to this treatment, bilateral deep brain stimulation of the globus pallidus internus (GPi) is considered. This study explores the efficacy of unilateral radiofrequency (RF) lesioning as an alternative surgical treatment for Meige syndrome. Methods We investigated six cases of medically refractory Meige syndrome treated with unilateral RF lesioning between October 2022 and August 2023. The procedures utilized the Leksell Stereotactic System (Elekta, Stockholm, Sweden) and the StealthStation S8 system (Medtronic, Dublin, Ireland). Target coordinates were initially set at 8-9 mm lateral and 1-2 mm inferior to the mid-commissure point (MCP) for the pallidothalamic tract (PTT), and 20 mm lateral, 2 mm anterior, and 3.0-4.5 mm inferior to the MCP for GPi, with fine adjustments based on MRI findings. Results The mean age of patients was 53. 3 ±16.5 years. Five patients underwent PTT RF lesioning, while one received GPi RF lesioning (pallidotomy). No surgical complications were reported. The Burke-Fahn-Marsden Dystonia Rating Scale scores were 32.9 ± 19.4 preoperatively and 17.7 ± 13.9 three months postoperatively, reflecting an average improvement of 42.7%. The Jankovic Rating Scale scores were 7.17 ± 0.76 preoperatively, 2.33 ± 2.34 the day after surgery (average improvement of 67%), and 3.50 ± 1.64 three months postoperatively (average improvement of 51%). Bilateral facial symptoms improved in four patients (67%). Conclusion Unilateral RF lesioning for Meige syndrome demonstrated the potential to improve bilateral symptoms and may be considered a viable treatment option for patients with refractory cases.

Progressive Encephalomyelitis with Rigidity and Myoclonus In a Varicella Encephalitis Patient with Primary Meige syndrome

Progressive Encephalomyelitis with Rigidity and Myoclonus In a Varicella Encephalitis Patient with Primary Meige syndrome

Progressive Encephalomyelitis with Rigidity and Myoclonus in a Varicella Encephalitis patient with Primary Meige syndrome

Progressive Encephalomyelitis with Rigidity and Myoclonus in a Varicella Encephalitis patient with Primary Meige syndrome

Structural network topologies are associated with deep brain stimulation outcomes in Meige syndrome

Deep brain stimulation (DBS) is an effective therapy for Meige syndrome (MS). However, the DBS efficacy varies across MS patients and the factors contributing to the variable responses remain enigmatic. We aim to explain the difference in DBS efficacy from a network perspective. We collected preoperative T1-weighted MRI images of 76 MS patients who received DBS in our center. According to the symptomatic improvement rates, all MS patients were divided into two groups: the high improvement group (HIG) and the low improvement group (LIG). We constructed group-level structural covariance networks in each group and compared the graph-based topological properties and interregional connections between groups. Subsequent functional annotation and correlation analyses were also conducted. The results indicated that HIG showed a higher clustering coefficient, longer characteristic path length, lower small-world index, and lower global efficiency compared with LIG. Different nodal betweennesses and degrees between groups were mainly identified in the precuneus, sensorimotor cortex, and subcortical nuclei, among which the gray matter volume of the left precentral gyrus and left thalamus were positively correlated with the symptomatic improvement rates. Moreover, HIG had enhanced interregional connections within the somatomotor network and between the somatomotor network and default-mode network relative to LIG. We concluded that the high and low DBS responders have notable differences in large-scale network architectures. Our study sheds light on the structural network underpinnings of varying DBS responses in MS patients.

Effects of onabotulinum toxin type A injections in patients with Meige's syndrome.

Meige's syndrome is a type of facial dystonia characterized by the simultaneous occurrence of blepharospasm and oromandibular dystonia. Although botulinum toxin type A (OBTA) injections are the standard treatment, evidence of their effectiveness and safety in this scenario is still lacking. Our research aimed to evaluate the improvement and occurrence of side effects following injections of onabotulinum toxin type A (OBTA) in patients with Meige's syndrome. Patients with Meige's syndrome undergoing botulinum toxin injections were enrolled in this study. We assessed dystonia intensity before and 14 days after OBTA injection using the Burke-Fahn-Marsden Dystonia Rating Scale (BFMDRS) to measure the response of symptoms in the eyes (blepharospasm) and mouth (oromandibular dystonia). Other variables, such as dosage, side effects, and demographic data, were also recorded. The study included 41 participants, with a mean age of 67.7 years and a female-to-male ratio of 3.5:1. The mean BFMDRS score before the injections was 8.89, and after 14 days, it was 2.88. The most reported side effect was ptosis, with a 7.3% incidence. OBTA significantly reduced dystonia severity (p < 0.0001). The clinical response for the blepharospasm component was superior to the oromandibular dystonia component. Our results support that OBTA seems to be an effective and safe therapeutic option for treating Meige's syndrome. The effect of OBTA was more pronounced in the treatment of blepharospasm than in oromandibular dystonia.

Association analyses between the variants of SNAP25, SV2C and ST3GAL2 and the efficacy of botulinum toxin A in the treatment of the primary Meige syndrome

ObjectiveIndividual differences were observed in the clinical efficacy of Botulinum toxin A (BoNT-A) in the treatment of the primary Meige syndrome. Our study aimed to explore the potential associations between the clinical efficacy of BoNT-A in the treatment of the primary Meige syndrome and variants of SNAP25, SV2C and ST3GAL2, which are involving in the translocation of the BoNT-A in vivo. MethodsPatients with the primary Meige syndrome treated with BoNT-A were enrolled. Clinical efficacy was evaluated by the maximum improvement rate of motor symptoms and the duration of efficacy. Variants of SNAP25, SV2C and ST3GAL2 were obtained by Sanger sequencing. Another cohort diagnosed with primary cervical dystonia was also enrolled in the replication stage. ResultsAmong the 104 primary Meige syndrome patients, 80 patients (76.9%) had a good efficacy (the maximum improvement rate of motor symptoms ≥30%) and 24 (23. 1%) had a poor (the maximum improvement rate of motor symptoms <30%). As to the duration of efficacy, 52 patients (50.0%) had a long duration of efficacy (≥4 months), and 52 (50.0%) had a short (<4 months). In terms of primary Meige syndrome, SNAP25 rs6104571 was found associating with the maximum improvement rate of motor symptoms (Genotype: P = 0.02, OR = 0.26; Allele: P = 0.013, OR = 0.29), and SV2C rs31244 was found associating with the duration of efficacy (Genotype: P = 0.024, OR = 0.13; Allele: P = 0.012, OR = 0.13). Besides, we also conducted the association analyses between the variants and BoNT-A-related adverse reactions. Although, there was no statistical difference between the allele of SV2C rs31244 and BoNT-A-related adverse reactions, there was a trend (P = 0.077, OR = 2.56). In the replication stage, we included 39 patients with primary cervical dystonia to further expanding the samples' size. Among the 39 primary cervical dystonia patients, 25 patients (64.1%) had a good efficacy (the maximum improvement rate of motor symptoms ≥50%) and 14 (35.9%) had a poor (the maximum improvement rate of motor symptoms <50%). As to the duration of efficacy, 32 patients (82.1%) had a long duration of efficacy (≥6 months), and 7 (17.9%) had a short (<6 months). Integrating primary Meige syndrome and primary cervical dystonia, SV2C rs31244 was still found associating with the duration of efficacy (Genotype: P = 0.002, OR = 0. 23; Allele: P = 0.001, OR = 0. 25). ConclusionIn our study, SNAP25 rs6104571 was associated with the maximum improvement rate of motor symptoms in patients with primary Meige syndrome treated with BoNT-A, and patients carrying this variant had a lower improvement rate of motor symptoms. SV2C rs31244 was associated with duration of treatment in patients with primary Meige syndrome treated with BoNT-A and patients carrying this variant had a shorter duration of treatment. Patients with primary Meige syndrome carrying SV2C rs31244 G allele have an increase likelihood of BoNT-A-related adverse reactions. Involving 39 patients with primary cervical dystonia, the results further verify that SV2C rs31244 was associated with duration of treatment and patients carrying this variant had a shorter duration of treatment.

Pallidal versus subthalamic deep brain stimulation for Meige syndrome: A systematic review and meta-analysis

BackgroundGlobus pallidus internus (GPi) and subthalamic nucleus (STN) are two common deep brain stimulation (DBS) targets. This meta-analysis was to compared the efficacy and safety of these two DBS targets for the treatment of Meige syndrome (MS). MethodsA systematic search was performed using EMBASE, MEDLINE, the Cochrane Library, and ClinicalTrials.gov to identify DBS trials for MS. Review Manager 5.3 was used to perform meta-analysis and the mean difference (MD) was analyzed and calculated with a random effect model. Pearson's correlation coefficients and meta-regression analyses were utilized to identify relevant predictive markers. ResultsTwenty trials involving 188 participants with GPi-DBS and 110 individuals with STN-DBS were eligible. Both groups showed improvement of the Burke-Fahn-Marsden Dystonia Rating Scale-Movement (BFMDRS-M) and Disability (BFMDRS-D) scores (BFMDRS-M: MD = 10.57 [7.74–13.41] for GPi-DBS, and MD = 8.59 [4.08–13.11] for STN-DBS; BFMDRS-D: MD = 5.96 [3.15–8.77] for GPi-DBS, and MD = 4.71 [1.38–8.04] for STN-DBS; all P < 0.001) from baseline to the final follow-up, while no notable disparity in improvement rates was observed between them. Stimulation-related complications occurrence was also similar between two groups (38.54 ± 24.07% vs. 43.17 ± 29.12%, P = 0.7594). Simultaneously, preoperative BFMDRS-M score and disease duration were positively connected with the relative changes in BFMDRS-M score at the final visit. ConclusionBoth GPi-DBS and STN-DBS are effective MS therapies, with no differences in efficacy or the frequency of stimulation-related problems. Higher preoperative scores and longer disease duration probably predict greater improvement.

Meige Syndrome as a Craniofacial Type of Dystonia Treatable by Dual Dopaminergic Modulation Using L-DOPA/Chlorpromazine: A Case Report.

Meige Syndrome as a Craniofacial Type of Dystonia Treatable by Dual Dopaminergic Modulation Using L-DOPA/Chlorpromazine: A Case Report.

Deep brain stimulation of the subthalamic nucleus for primary Meige syndrome: clinical outcomes and predictive factors.

Deep brain stimulation (DBS) of the subthalamic nucleus (STN) has demonstrated efficacy against multiple types of dystonia, but only a few case reports and small-sample studies have investigated the clinical utility of STN-DBS for Meige syndrome, a rare but distressing form of craniofacial dystonia. Furthermore, the effects of DBS on critical neuropsychological sequelae, such as depression and anxiety, are rarely examined. In this study, the authors investigated the therapeutic efficacy of STN-DBS for both motor and psychiatric symptoms of Meige syndrome. The authors retrospectively reviewed consecutive patients with Meige syndrome receiving bilateral STN-DBS at their institution from January 2016 to June 2023. Motor performance and nonmotor features including mood, cognitive function, and quality of life (QOL) were evaluated using standardized rating scales at baseline and at final postoperative follow-up. Clinical and demographic factors influencing postoperative motor outcome were evaluated by uni- and multivariable linear regression models. Fifty-one patients were ultimately included, with a mean ± SD follow-up duration of 27.3 ± 18.0 months. The mean Burke-Fahn-Marsden Dystonia Rating Scale (BFMDRS) movement score improved from 12.9 ± 5.2 before surgery to 5.3 ± 4.2 at the last follow-up (mean improvement 58.9%, p < 0.001) and the mean BFMDRS disability score improved from 5.6 ± 3.3 to 2.9 ± 2.9 (mean improvement 44.6%, p < 0.001). Hamilton Depression and Anxiety Rating Scale scores also improved by 35.3% and 34.2%, respectively, and the postoperative 36-item Short-Form Health Survey score indicated substantial QOL enhancement. Global cognition remained stable after treatment. Multiple linear regression analysis identified disease duration (β = -0.241, p = 0.027), preoperative anxiety severity (β = -0.386, p = 0.001), and volume of activated tissue within the dorsolateral (sensorimotor) STN (β = 0.483, p < 0.001) as independent predictors of motor outcome. These findings support STN-DBS as an effective and promising therapy for both motor and nonmotor symptoms of Meige syndrome. Timely diagnosis, treatment of preoperative anxiety, and precise electrode placement within the dorsolateral STN are essential for optimal clinical outcome.

Management of Meige syndrome with bilateral trigeminal and facial nerves combing.

Meige syndrome (MS) is an adult-onset segmental dystonia for which no satisfactory remedy currently exists. Our team developed a novel surgical approach called bilateral trigeminal/facial nerve combing (BTFC). This study aimed to evaluate the outcomes of patients who underwent BFTC (Clinical Trial Registry Number: ChiCTR2000033481). We assigned 22 patients with MS to undergo BTFC. The primary outcome was assessed using the movement subscale of the Burke-Fahn-Marsden Dystonia Rating Scale (BFMDRS-M) at 12 months postoperatively. The second outcome was evaluated using the Medical Outcome Study (MOS) 36-item Short Form Health Survey (SF-36), the dysfunction subscale of the Burke-Fahn-Marsden Dystonia Rating Scale (BFMDRS-D), and the sub-item scores of the BFMDRS-M. Safety outcomes included the House-Brackmann (HB) functional grading score and the visual analog scale (VAS) for facial numbness. At the final follow-up at 12 months, the BFMDRS-M showed a mean improvement of 70.7% from baseline. Mean scores of the BFMDRS-M sub-motor (including the eyes, mouth, and speech/swallowing) improved by 65.6, 81.00, and 60%, respectively. The median score of the total BFMDRS-D score was 0.70 ± 1.17 compared with 1.86 ± 2.21 at baseline. There were no serious operative complications in this population. The quality of life of the patients significantly improved (P < 0.05). BFTC has proven to be effective in relieving the symptoms of Meige syndrome. This novel surgical approach offers a new alternative treatment for patients who have failed to respond to medications, botulinum toxin injections, and deep brain stimulation (DBS). https://www.chictr.org.cn/bin/project/edit?pid=54567, ChiCTR2000033481.

A localized pallidal physiomarker in Meige syndrome.

Oscillatory patterns in local field potentials (LFPs) have been recognized as disease-specific physiomarkers, particularly in the context of Parkinson's disease and cervical dystonia. This characteristic oscillatory feature is currently employed in adaptive deep brain stimulation (aDBS). However, for other types of dystonia, especially Meige syndrome, a distinct physiomarker of this nature is yet to be identified. Local field potentials were recorded during microelectrode-guided deep brain stimulation surgery from 28 patients with primary Meige syndrome. Before surgery, the severity of patients' motor syndrome were assessed using the Burke-Fahn-Marsden Dystonia Rating Scale-Motor (BFMDRS-M). An instantaneous oscillation detection method was employed to identify true narrowband oscillations. Subsequently, a linear mixed effects model was utilized to examine the relationship between oscillatory activities (including power amplitude and burst duration) and symptom severity. The focal peaks of "oscillatory activities" detected were predominantly concentrated in the narrow theta band (4-8 Hz), constituting 81.5% of the total detected oscillations in all recording sites near active DBS contacts in the globus pallidus internus (GPi). The linear mixed effects model revealed a positive correlation between the theta burst duration and the severity of preoperative motor impairment, but no correlation with postoperative motor scores. Additionally, there was no significant lateralization effect observed between the left and right GPi. Our findings suggest that the exaggerated narrowband theta activity (mainly the burst duration) in the GPi is predictive of dystonia symptom severity and may be used as a physiomarker for optimized DBS target during surgery and adaptive DBS for the treatment of Meige syndrome.

Sjogren's syndrome meets Meige's syndrome

This report details a rare case where a patient simultaneously suffered from Sjogren's syndrome (SS) and Meige's syndrome (MS). SS, an autoimmune disorder, and MS, a rare neurological condition characterized by involuntary eyelid closure, presented in a 73-year-old male. The patient had been experiencing dry eye symptoms for the past 5 years, with the onset of eyelid spasms and tetanic eye closure occurring 3 years ago. Traditional treatments, including subthalamic nucleus deep brain stimulation, provided only temporary relief. Diagnostic evaluations, including blood tests and imaging, confirmed SS and MS coexistence. Treatment involved a combination of steroids, immunosuppressants, and immunoglobulin, leading to significant symptom relief. This case suggests a potential association between SS and the development of MS, highlighting the importance of immunomodulatory therapy in managing neurological symptoms. Further research is needed to explore the relationship between these two conditions and to develop more effective treatment strategies.

Subthalamic nucleus deep brain stimulation in primary Meige syndrome: motor and non-motor outcomes.

Deep brain stimulation (DBS) has emerged as a promising treatment for movement disorders. This prospective study aims to evaluate the effects of bilateral subthalamic nucleus DBS (STN-DBS) on motor and non-motor symptoms in patients with primary Meige syndrome. Thirty patients who underwent bilateral STN-DBS between April 2017 and June 2020 were included. Standardized and validated scales were utilized to assess the severity of dystonia, health-related quality of life, sleep, cognitive function and mental status at baseline and at 1 year and 3 years after neurostimulation. The Burke-Fahn-Marsden Dystonia Rating Scale movement scores showed a mean improvement of 63.0% and 66.8% at 1 year and 3 years, respectively, after neurostimulation. Similarly, the Burke-Fahn-Marsden Dystonia Rating Scale disability scores improved by 60.8% and 63.3% at the same time points. Postoperative quality of life demonstrated a significant and sustained improvement throughout the follow-up period. However, cognitive function, mental status, sleep quality and other neuropsychological functions did not change after 3 years of neurostimulation. Eight adverse events occurred in six patients, but no deaths or permanent sequelae were reported. Bilateral STN-DBS is a safe and effective alternative treatment for primary Meige syndrome, leading to improvements in motor function and quality of life. Nevertheless, it did not yield significant amelioration in cognitive, mental, sleep status and other neuropsychological functions after 3 years of neurostimulation.

Abnormal Movement and Literature Review on Meige's Syndrome in a Mining Context

Abnormal Movement and Literature Review on Meige's Syndrome in a Mining Context

Meige syndrome following COVID infection.

Meige syndrome following COVID infection.

Deep Brain Stimulation for Focal or Segmental Craniocervical Dystonia in Patients Who Have Failed Botulinum Neurotoxin Therapy-A Narrative Review of the Literature.

(1) Background: The first-line treatment for patients with focal or segmental dystonia with a craniocervical distribution is still the intramuscular injection of botulinum neurotoxin (BoNT). However, some patients experience primary or secondary treatment failure from this potential immunogenic therapy. Deep brain stimulation (DBS) may then be used as a backup strategy in this situation. (2) Methods: Here, we reviewed the current study literature to answer a specific question regarding the efficacy and safety of the use of DBS, particularly for cervical dystonia (CD) and Meige syndrome (MS) in patients with documented treatment failure under BoNT. (3) Results: There are only two studies with the highest level of evidence in this area. Despite this clear limitation, in the context of the narrowly defined research question of this paper, it is possible to report 161 patients with CD or MS who were included in studies that were able to show a statistically significant reduction in dystonic symptoms using DBS. Safety and tolerability data appeared adequate. However, much of the information is based on retrospective observations. (4) Conclusions: The evidence base in this area is in need of further scientific investigation. Most importantly, more randomized, controlled and double-blind trials are needed, possibly including a head-to-head comparison of DBS and BoNT.