Segmental Dystonia Research Articles

The clinical spectrum and pathogenesis associated with KMT2B variants in Chinese pediatric patients

ObjectiveTo evaluate the clinical spectrum and pathogenesis associated with KMT2B variants in Chinese children with dystonia or developmental delay. MethodsWe reported twenty-seven (fourteen males and thirteen females) pediatric patients with KMT2B variants identified via next-generation sequencing from a single Chinese center. Moreover, transcriptomics and proteomics assays were performed on fibroblasts from patients with different genotypes to investigate the pathogenic mechanisms involved. ResultsTwenty-six patients had dystonia including generalized dystonia (n = 19), multifocal dystonia (n = 6), and segmental dystonia (n = 1), and one patient had nondystonic severe-developmental delay (DD). All the twenty-six patients had complex dystonia compounded with other manifestations of movement disorders (tremor (n = 6), myoclonus (n = 5), status dystonicus (n = 2), and tic (n = 1)) or dysmorphic features and developmental delay. The onset of dystonia was between 1 month and 13 years 8 months (median 4 years 4 months). Dystonia was aggravated by fever (n = 11), and diurnal and climate fluctuations (n = 4). Eleven patients underwent deep brain stimulation and experienced significant improvements in motor function and disability. We identified twenty-six intragenic heterozygous KMT2B pathogenic variants and one Chr:19q13.12 contiguous gene deletion. Sixteen variants were novel. Differentially expressed genes induced by KMT2B variants were significantly enriched for mitochondria-related biological processes in patient fibroblasts. As a result, mitochondrial morphology of mitochondria was altered, and aerobic respiration was impaired. ConclusionOur study reports the pediatric cases of KMT2B-related disorder from a single center in China. Additionally, our study highlights the role of KMT2B variants in mitochondrial dysfunction.

Clinical and physiological characteristics of tremor in a large cohort of focal and segmental dystonia

ObjectiveTremor is a frequent co-occurring feature in patients with dystonia, especially in focal and segmental dystonia. Clinical studies have shown that tremor is more commonly observed when dystonia spreads to contiguous body regions. However, there is insufficient characterization of tremor physiology in focal and segmental forms of dystonia. We aimed to ascertain the characteristics of tremor presenting in these specific subtypes.MethodsWe enrolled dystonia patients with head and arm tremors presenting to our center. We categorized these participants as focal and segmental dystonia following the Movement Disorders Society guidelines. We recorded the frequency, amplitude, rhythmicity, burst duration, and discharge pattern on accelerometer and electromyography recordings. We compared the physiology of tremors in focal vs. segmental dystonia. We determined whether the physiology was affected by clinical features such as demographics, age at onset, dystonia duration, alcohol responsiveness, family history, and botulinum toxin responsiveness.Results72 patients, mainly focal cervical dystonia and focal cervical + arm or cranial dystonia (segmental) were enrolled. In the analysis of the head tremor recordings (n = 66; frequency range 3–6.5 Hz), we found that focal vs. segmental dystonia comparisons revealed a significantly lower frequency (mean ± standard deviation; 4.0 ± 0.9 Hz vs. 4.7 ± 1.0 Hz; p = 0.02), lower amplitude (0.004 ± 0.008 g2/Hz vs. 0.006 ± 0.008 g2/Hz; p = 0.03) and longer muscle burst durations (111.1 ± 40.4 ms vs. 91.5 ± 24 ms; p = 0.04). In the analysis of arm tremor recordings (n = 31; frequency range 3.5–7 Hz), we found focal vs. segmental dystonia comparison revealed a lower amplitude (0.04 ± 0.07 g2/Hz vs. 0.06 ± 0.06 g2/Hz; p = 0.045). In the stepwise regression analysis, the age at evaluation (β - 0.44; p = 0.006) and age at onset (β - 0.61; p = 0.005) significantly predicted the head tremor frequency whereas the alcohol responsiveness tended to predict the amplitude of the head tremor (β - 0.5; p = 0.04) and the arm tremor (β - 0.6; p = 0.02).ConclusionOur study found that the physiological characteristics of tremor in focal and segmental dystonia are somewhat distinct, suggesting that the spread of dystonia symptoms from one body region to another may have a bearing on the physiology of co-occurring tremor. The frequency of head tremors in younger participants was observed to be higher compared to older participants. The head and arm tremor tended be less severe in patients reporting alcohol responsiveness.

Ứng dụng tiêm Botulinum Neurotoxin dưới hướng dẫn của siêu âm và điện cơ trong điều trị loạn trương lực cơ cổ: Ca lâm sàng

Dystonia is a movement disorder characterized by persistent or intermittent muscle contractions, involuntary, creating repetitive and/or abnormal postures and movements. Dystonic movements result in characteristic twisting or tremor patterns. Dystonia often begins or worsens with intentional movements, combined with excessive muscle activation. Dystonia is classified according to the affected body regions: focal dystonia, segmental dystonia, multifocal dystonia, hemidystonia, and generalized dystonia. Anterocollis is a type of cervical dystonia, caused by persistent, repetitive contractions of neck muscle groups, leading to excessive neck flexion. Anterocollis is described in the context of movement disorders in Parkinson’s syndrome (Parkinson’s disease, multiple system atrophy, etc.). Treatment of dystonia is primarily symptomatic: medications, Botulinum Neurotoxin (BoNT) injections, surgery, and physical therapy. Among these, BoNT injections are considered the first choice for focal or segmental dystonia.Botulinum Neurotoxin acts at the neuromuscular junction, leading to muscle paralysis. BoNT injections require injection equipment, surface disinfection, and determination of the injection site based on clinical landmarks. Some deep and difficult injections require specialized techniques such as electromyography (EMG) and ultrasound. In the case of anterocollis, BoNT is often applied to both superficial and deep muscles. To achieve effectiveness and limit complications during and after injection, practitioners often use combined EMG and ultrasound techniques. We present a clinical case to illustrate the value of using BoNT injections under the simultaneous guidance of EMG and ultrasound in treating anterocollis at the Neurology Department of Hanoi Medical University Hospital.

Role of Botulinum Toxin in Treatment of Secondary Dystonia: A Case Series and Overview of Literature.

Dystonia can present in primary and secondary forms, depending on co-occurring symptoms and syndromic associations. In contrast to primary dystonia, secondary forms of dystonia are often associated with lesions in the putamen or globus pallidus. Such disorders are commonly neurodegenerative or neurometabolic conditions which produce varied neurologic as well as systemic manifestations other than dystonia. Chemo-denervation with botulinum toxin has been successfully used for focal or segmental dystonia. However, studies evaluating the effect of BoNT therapy on patients with secondary dystonia are sparse, given the heterogeneity in etiology and presentation. We present a series of patients with secondary dystonia who were managed with botulinum toxin therapy. Patients included in this series had a confirmed neurometabolic cause of dystonia. A total of 14 patients, with ages ranging from 17 to 36 years, with disorders including Wilson's disease, pantothenate kinase-associated neurodegeneration (PKAN), Niemann-Pick disease type C (NPC), glutaric aciduria type 1, Sanfilippo syndrome (Mucopolysaccharidosis Type IIIb), and GM2 gangliosidosis (Sandhoff disease) are presented. Most patients experienced a mild to moderate improvement in treated dystonia with benefits ranging from 6 to 12 weeks, with the median length of the benefits lasting approximately eight weeks, without any significant adverse effects. Although the secondary causes of dystonia are complex and diverse, our presented data and the available reports of the use of botulinum toxin support the conclusion that chemo-denervation plays an important role in symptom alleviation.

Feasibility of Endovascular Deep Brain Stimulation of Anterior Nucleus of the Thalamus for Refractory Epilepsy.

Deep brain stimulation (DBS) has developed into an effective therapy for several disease states including treatment-resistant Parkinson disease and medically intractable essential tremor, as well as segmental, generalized and cervical dystonia, and obsessive-compulsive disorder (OCD). Dystonia and OCD are approved with Humanitarian Device Exemption. In addition, DBS is also approved for the treatment of epilepsy in the anterior nucleus of the thalamus. Although overall considered an effective treatment for Parkinson disease and epilepsy, a number of specific factors determine the treatment success for DBS including careful patient selection, effective postoperative programming of DBS devices and accurate electrode placement. Furthermore, invasiveness of the procedure is a rate limiter for patient adoption. It is desired to explore a less invasive way to deliver DBS therapy. Here, we report for the first time the direct comparison of endovascular and parenchymal DBS in a triplicate ovine model using the anterior nucleus of the thalamus as the parenchymal target for refractory epilepsy. Triplicate ovine studies show comparable sensing resolution and stimulation performance of endovascular DBS with parenchymal DBS. The results from this feasibility study opens up a new frontier for minimally invasive DBS therapy.

Long-term follow-up of pallidal deep brain stimulation for craniocervical dystonia: is the globus pallidus internus the best target?

Craniocervical dystonia (CCD) is a common type of segmental dystonia, which is a disabling disease that has been frequently misdiagnosed. Blepharospasm or cervical dystonia is the most usual symptom initially. Although deep brain stimulation (DBS) of the globus pallidus internus (GPi) has been widely used for treating CCD, its clinical outcome has been primarily evaluated in small-scale studies. This research examines the sustained clinical effectiveness of DBS of the GPi in individuals diagnosed with CCD. The authors report 24 patients (14 women, 10 men) with refractory CCD who underwent DBS of the GPi between 2016 and 2023. The severity and disability of the dystonia were evaluated using the Burke-Fahn-Marsden Dystonia Rating Scale (BFMDRS). The BFMDRS scores were collected preoperatively, 6 months postoperatively, and at the most recent follow-up visit. The mean age at onset was 52.0 ± 11.0 years (range 33-71 years) and the mean disease duration was 63.3 ± 73.3 months (range 7-360 months) (values for continuous variables are expressed as the mean ± SD). The mean follow-up period was 37.5 ± 23.5 months (range 6-84 months). The mean total BFMDRS motor scores at the 3 different time points were 13.3 ± 9.4 preoperatively, 5.0 ± 4.7 (55.3% improvement, p < 0.001) at 6 months, and 4.5 ± 3.6 (56.6% improvement, p < 0.001) at last follow-up. The outcomes were deemed poor in 6 individuals. Inferences drawn from the findings suggest that DBS of the GPi has long-lasting effectiveness and certain limitations in managing refractory CCD. The expected stability of the clinical outcome is not achieved. Patients with specific types of dystonia might consider targets other than GPi for a more precise therapy.

Sex Differences in Dystonia.

Prior studies have indicated that female individuals outnumber male individuals for certain types of dystonia. Few studies have addressed factors impacting these sex differences or their potential biological mechanisms. To evaluate factors underlying sex differences in the dystonias and explore potential mechanisms for these differences. Data from individuals with various types of dystonia were analyzed in relation to sex. Data came from two different sources. One source was the Dystonia Coalition database, which contains predominantly idiopathic adult-onset focal and segmental dystonias. The second source was the MDSGene database, which contains predominantly early-onset monogenic dystonias. The 3222 individuals from the Dystonia Coalition included 71% female participants and 29% male participants for an overall female-to-male ratio (F:M) of 2.4. This ratio varied according to body region affected and whether dystonia was task-specific. The female predominance was age-dependent. Sex did not have a significant impact on co-existing tremor, geste antagoniste, depression or anxiety. In the 1377 individuals from the MDSGene database, female participants outnumbered male participants for some genes (GNAL, GCH1, and ANO3) but not for other genes (THAP1, TH, and TOR1A). These results are in keeping with prior studies that have indicated female individuals outnumber male individuals for both adult-onset idiopathic and early onset monogenic dystonias. These results extend prior observations by revealing that sex ratios depend on the type of dystonia, age, and underlying genetics.

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.

An Empirical Comparison of Commonly Used Universal Rating Scales for Dystonia.

There are several widely used clinical rating scales for documenting the severity and distribution of various types of dystonia. The goal of this study was to evaluate the performance of the most commonly used scales in a large group of adults with the most common types of isolated dystonia. Global Dystonia Rating Scale (GDRS) and the Burke-Fahn-Marsden Dystonia Rating Scale (BFM) scores were obtained for 3067 participants. Most had focal or segmental dystonia, with smaller numbers of multifocal or generalized dystonia. These scales were also compared for 209 adults with cervical dystonia that had Toronto Western Spasmodic Torticollis Rating Scale (TWSTRS) scores and 210 adults with blepharospasm that had Blepharospasm Severity Scale (BSRS) scores. There were strong correlations between the GDRS and BFM total scores (r = 0.79) and moderate correlations for their sub scores (r > 0.5). Scores for both scales showed positive skew, with an overabundance of low scores. BFM sub-scores were not normally distributed, due to artifacts caused by the provoking factor. Relevant sub-scores of the GDRS and BFM also showed moderate correlations with the TWSTRS (r > 0.5) for cervical dystonia and the BSRS (r > 0.5) for blepharospasm. The BFM is more widely used than the GDRS, but these results suggest the GDRS may be preferable for focal and segmental dystonias. The overabundance of very low scores for both scales highlights challenges associated with discriminating very mild dystonia from other abnormal movements or variants of normal behavior.

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.

Depression impact on subjective and objective severity of cervical and segmental dystonia

Depression impact on subjective and objective severity of cervical and segmental dystonia

Altered coupling of resting-state cerebral blood flow and functional connectivity in Meige syndrome.

Meige syndrome (MS) is an adult-onset segmental dystonia disease, mainly manifested as blepharospasm and involuntary movement caused by dystonic dysfunction of the oromandibular muscles. The changes of brain activity, perfusion and neurovascular coupling in patients with Meige syndrome are hitherto unknown. Twenty-five MS patients and thirty age- and sex-matched healthy controls (HC) were prospectively recruited in this study. All the participants underwent resting-state arterial spin labeling and blood oxygen level-dependent examinations on a 3.0 T MR scanner. The measurement of neurovascular coupling was calculated using cerebral blood flow (CBF)-functional connectivity strength (FCS) correlations across the voxels of whole gray matter. Also, voxel-wised analyses of CBF, FCS, and CBF/FCS ratio images between MS and HC were conducted. Additionally, CBF and FCS values were compared between these two groups in selected motion-related brain regions. MS patients showed increased whole gray matter CBF-FCS coupling relative to HC (t = 2.262, p = 0.028). In addition, MS patients showed significantly increased CBF value in middle frontal gyrus and bilateral precentral gyrus. The abnormal elevated neurovascular coupling of MS may indicate a compensated blood perfusion in motor-related brain regions and reorganized the balance between neuronal activity and brain blood supply. Our results provide a new insight into the neural mechanism underlying MS from the perspective of neurovascular coupling and cerebral perfusion.

Improvement in Cervical Dystonia – Outcomes of a Prospective, Multicenter, International Registry of Deep Brain Stimulation (DBS) (P11-11.002)

<h3>Objective:</h3> To report real-world outcomes of Dystonia patients implanted with a Multiple Independent Current Control (MICC)-based Directional DBS system. <h3>Background:</h3> Management of dystonia using Deep Brain Stimulation (DBS) is a well-established therapeutic approach. However, optimal DBS target sites in patients with cervical (focal) versus generalized dystonia are thought to diverge and be specific for particular connections (Horn 2022). DBS devices equipped with capabilities such as directionality and Multiple Independent Current Control (MICC) may offer potential for improved clinical outcomes. Here, we report a sub-analysis of patients with cervical dystonia only or dystonia with cervical involvement from an on-going, multicenter registry. <h3>Design/Methods:</h3> In this prospective, on-label, multi-center, international registry (ClinicalTrials.gov Identifier: NCT02686125) of dystonia, enrolled subjects received MICC-based directional DBS systems (Vercise, Boston Scientific). Subjects were followed up to 3 years (post-implant). Several study assessments evaluating their dystonia symptoms (e.g., TWSTRS), quality of life (GIC) and overall satisfaction were administered. Adverse Events were also collected. <h3>Results:</h3> A total of 43-patients (mean age 56.9-years, 58% females) with focal (cervical) dystonia only and 83-patients (mean 41.95-years, 61% females) with generalized or segmental dystonia with cervical involvement who underwent pallidal DBS were prospectively evaluated. Both groups reported significant improvement in overall TWSTRS scores – however the extent varied. In the cervical only cohort, a 19.9-point improvement was noted at 6-months (n=25) and sustained up to 1-year (23.2-point improvement, n=20). In those with generalized or segmental dystonia (with cervical involvement), a 9.7-point. and 7.3-improvement in overall TWSTRS scores was noted at 6- (n = 50) and 12-months (n = 38), respectively. <h3>Conclusions:</h3> This registry represents the first comprehensive, large-scale collection of real-world outcomes associated with dystonia patients implanted with a directional DBS system capable of MICC. Preliminary results demonstrate significant improvement in patients with cervical dystonia (either alone or with other regions involved) following DBS. <b>Disclosure:</b> Dr. Albanese has received personal compensation in the range of $500-$4,999 for serving on a Scientific Advisory or Data Safety Monitoring board for Boston Scientific. Dr. Albanese has received personal compensation in the range of $500-$4,999 for serving as an Editor, Associate Editor, or Editorial Advisory Board Member for Frontiers Publishing Group. Dr. Albanese has a non-compensated relationship as a President-Elect with International Association on Parkinsonism and Related Disorders that is relevant to AAN interests or activities. Roshini Jain has received personal compensation for serving as an employee of Boston Scientific. Roshini Jain has received stock or an ownership interest from Boston Scientific. Lilly Chen has received personal compensation for serving as an employee of Boston Scientific . Joachim Krauss has received personal compensation in the range of $500-$4,999 for serving on a Scientific Advisory or Data Safety Monitoring board for Inomed. Joachim Krauss has received personal compensation in the range of $500-$4,999 for serving on a Scientific Advisory or Data Safety Monitoring board for aleva. Joachim Krauss has received personal compensation in the range of $500-$4,999 for serving on a Scientific Advisory or Data Safety Monitoring board for Boston.

Mutation screening of AOPEP variants in a large dystonia cohort.

Recently, AOPEP has been identified to be a novel causative gene of autosomal-recessive dystonia. However, no large cohort study has been conducted to confirm the association. We aimed to systematically evaluate the genetic associations of AOPEP with dystonia in a large Chinese dystonia cohort. We analyzed rare variants of AOPEP in 878 dystonia patients with whole-exome sequencing. The over-representation of rare variants in patients was examined with Fisher's exact test at allele and gene levels. Among the 878 patients with dystonia, we found two patients with biallelic likely pathogenic variants in the AOPEP gene. One patient carried putative compound heterozygous variants (p.A212D and p.G216R) and presented with childhood-onset segmental dystonia involving the upper limbs and craniocervical muscles accompanied by myoclonus of the dystonia affected areas. One patient carried homozygote of p.M291Nfs*68 and presented with adult-onset isolated cervical dystonia. Another 15 patients were identified to carry heterozygous rare variants in AOPEP, including 2 loss-of-function variants (p.M291Nfs*68 and p.R493X) and 6 missense variants. One loss-of-function variant (p.R493X) was the same as previously reported. Nearly, all of the 15 patients carrying heterozygous variants in AOPEP presented with isolated dystonia with only craniocervical muscles affected, except for one patient who carried the p.R493X variant presented with segmental dystonia affecting the neck and right upper limb combined with parkinsonism. Gene-based burden analysis detected enrichment of rare variants and rare damaging variants of AOPEP in dystonia. Our study supplemented the evidence on the role of AOPEP in autosomal-recessive dystonia in Chinese population, and expanded the genotypic and phenotypic spectrum of AOPEP.

Two novel heterozygote mutations of ATM in a Chinese family with dystonia-dominant ataxia telangiectasia and literature review.

Ataxia-telangiectasia (A-T) is an autosomal recessive disorder with high clinical heterogeneity. A-T may present in complicated variable forms, including classic A-T and milder form of AT. Contrary to the classic A-T, the milder form does not present the cardinal features of A-T such as ataxia and telangiectasia. A few ATM mutations have been reported in variant A-T cases manifesting isolated generalized or segmental dystonia without any signs of classical A-T. An A-T pedigree with predominant dystonia was collected. Genetic testing was performed by targeted panel of genes involved in movement disorders. The candidate variants were further confirmed by Sanger sequencing. We then reviewed previously published literatures of genetically confirmed A-T cases with predominant dystonia and summarized the clinical characteristics of dystonia-dominant A-T. Two novel ATM mutations, p.I2683T and p.S2860P, were identified in the family. The proband presented isolated segmental dystonia without any signs of ataxia and telangiectasias. We reviewed the literatures and found that the patients with dystonia-dominant A-T tend to have a later-onset and slower progression of the disease. To our knowledge, this is the first report of A-T patient with predominant dystonia in China. Dystonia may appear as one of the predominant manifestations or initial symptom of A-T. Early ATM genetic testing should be considered for those patients with predominant dystonia, despite without accompanying ataxia or telangiectasia.

THE EFFECT OF DEEP BRAIN STIMULATION ON MOTOR FUNCTIONS AND QUALITY OF LIFE IN THE TREATMENT OF DYSTONIA

Background/Aims: The present study aims to evaluate the levels of depression and health-related quality of life (HRQoL) after surgical globus pallidus internus deep brain stimulation (Gpi-DBS) treatment in patients with generalized and segmental dystonia refractory to medical treatment. Methods: Seventeen patients diagnosed with primary and secondary dystonia who were selected for GPi-DBS by the neurology, neurosurgery, and psychiatry council were included in the study. The patients were divided into two groups: primary dystonia and secondary dystonia. All patients were evaluated using the Burke-Fahn-Marsden Dystonia Rating Scale (BFMDRS) to assess dystonia-related loss of function and disability, the Short Form 36 (SF-36) to assess HRQoL levels, and the Beck Depression Inventory (BDI) to assess depression levels before Gpi-DBS and 1 year after Gpi-DBS, retrospectively. Results: In this study, significant improvement in BFMDRS scores and significant improvement in HRQoL levels were observed after 1 year of Gpi-DBS treatment in all dystonia types. Moreover, significant improvement was found in dystonia severity and disability levels, and HRQoL levels in primary dystonia and secondary dystonia subgroups. Conclusions: We suggest that Gpi-DBS improves dystonia symptoms, and increases HRQoL levels in dystonia. In addition, this study is the first in Turkey to evaluate the effect of Gpi-DBS on HRQoL levels in dystonia. However, we believe that further research with more participants is also needed in Turkey in this regard.

Adult-onset KMT2B-related dystonia.

KMT2B-related dystonia (DYT-KMT2B, also known as DYT28) is an autosomal dominant neurological disorder characterized by varying combinations of generalized dystonia, psychomotor developmental delay, mild-to-moderate intellectual disability and short stature. Disease onset occurs typically before 10 years of age. We report the clinical and genetic findings of a series of subjects affected by adult-onset dystonia, hearing loss or intellectual disability carrying rare heterozygous KMT2B variants. Twelve cases from five unrelated families carrying four rare KMT2B missense variants predicted to impact protein function are described. Seven affected subjects presented with adult-onset focal or segmental dystonia, three developed isolated progressive hearing loss, and one displayed intellectual disability and short stature. Genome-wide DNA methylation profiling allowed to discriminate these adult-onset dystonia cases from controls and early-onset DYT-KMT2B patients. These findings document the relevance of KMT2B variants as a potential genetic determinant of adult-onset dystonia and prompt to further characterize KMT2B carriers investigating non-dystonic features.

The epidemiology of dystonia: the Hannover epidemiology study

The prevalence of dystonia has been studied since the 1980s. Due to different methodologies and due to varying degrees of awareness, resulting figures have been extremely different. We wanted to determine the prevalence of dystonia according to its current definition, using quality-approved registries and based on its relevance for patients, their therapy and the health care system. We applied a service-based chart review design with the City of Hannover as reference area and a population of 525,731. Barrier-free comprehensive dystonia treatment in few highly specialised centres for the last 30 years should have generated maximal dystonia awareness, a minimum of unreported cases and a high degree of data homogeneity. Prevalence [n/1mio] and relative frequency is 601.1 (100%) for all forms of dystonia, 251.1 (42%) for cervical dystonia, 87.5 (15%) for blepharospasm, 55.2 (9%) for writer’s cramp, 38.0 (6%) for tardive dystonia, 32.3 (5%) for musician’s dystonia, 28.5 (5%) for psychogenic dystonia, 26.6 (4%) for generalised dystonia, 24.7 (4%) for spasmodic dysphonia, 20.9 (3%) for segmental dystonia, 15.2 (3%) for arm dystonia and 13.3 (2%) for oromandibular dystonia. Leg dystonia, hemidystonia and complex regional pain syndrome-associated dystonia are very rare. Compared to previous meta-analytical data, primary or isolated dystonia is 3.3 times more frequent in our study. When all forms of dystonia including psychogenic, generalised, tardive and other symptomatic dystonias are considered, our dystonia prevalence is 3.7 times higher than believed before. The real prevalence is likely to be even higher. Having based our study on treatment necessity, our data will allow better allocation of resources for comprehensive dystonia treatment.

Adjuvant medical therapy in cervical dystonia after deep brain stimulation: A retrospective analysis.

BackgroundThere is limited information on optimization of symptomatic management of cervical dystonia (CD) after implantation of pallidal deep brain stimulation (DBS).ObjectivesTo describe the long-term, “real-world” management of CD patients after DBS implantation and the role of reintroduction of pharmacologic and botulinum toxin (BoNT) therapy.MethodsA retrospective analysis of patients with focal cervical or segmental craniocervical dystonia implanted with DBS was conducted.ResultsNine patients were identified with a mean follow-up of 41.7 ± 15.7 months. All patients continued adjuvant oral medication(s) to optimize symptom control post-operatively. Three stopped BoNT and four reduced BoNT dose by an average of 22%. All patients remained on at least one medication used to treat dystonia post-operatively.ConclusionOptimal symptom control was achieved with DBS combined with either BoNT and/or medication. We suggest utilization of adjuvant therapies such as BoNT and/or medications if DBS monotherapy does not achieve optimal symptom control.

Approach to the Treatment of Pediatric Dystonia

Dystonia is the most common movement disorder in the pediatric population. It can affect normal motor development and cause significant motor disability. The treatment of pediatric dystonia can be very challenging as many children tend to be refractory to standard pharmacological interventions. Pharmacological treatment remains the first-line approach in pediatric dystonia. However, despite the widespread use of different ani-dystonia medications, the literature is limited to small clinical studies, case reports, and experts’ opinions. Botulinum neurotoxin (BoNT) is a well-established treatment in adults with focal and segmental dystonia. Despite the widespread use of BoNT in adult dystonia the data to support its use in children is limited with the majority extrapolated from the spasticity literature. For the last 2 decades, deep brain stimulation (DBS) has been used for a wide variety of dystonic conditions in adults and children. DBS gained increased popularity in the pediatric population because of the dramatic positive outcomes reported in some forms of genetic dystonia and the subsequent consensus that DBS is generally safe and effective. This review summarizes the available evidence supporting the efficacy and safety of pharmacological treatment, BoNT, and DBS in pediatric dystonia and provides practical frameworks for the adoption of these modalities.