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Aim: To characterize motor disorders in children and young people with cerebral palsy (CP)., Method: This was a cross-sectional study of 582 children and young people with CP (mean age 9 years 7 months; range 11 months-19 years 9 months; standard deviation 4 years 11 months; 340 males) attending a rehabilitation clinic at a specialized children's hospital (May 2018-March 2020). Data on motor disorders, topography, functional classifications, and non-motor features, such as epilepsy, intellectual disability, and sensory impairments, were collected using the Australian Cerebral Palsy Register CP Description Form., Results: Fifty-five per cent (n = 321) of children and young people with CP presented with multiple motor disorders, often affecting the same limb(s). The most common motor disorders were spasticity and dystonia (50%), spasticity only (36%), and dystonia only (6%), but 18 different combinations were identified, including choreoathetosis, ataxia, and generalized hypotonia with increased reflexes. Children with spasticity only had less severe functional deficits (p < 0.001) and lower rates of associated intellectual disability (p < 0.01) and epilepsy (p < 0.001) than those with both spasticity and dystonia., Interpretation: Multiple motor disorders in children and young people with CP are common and associated with more severe functional impairment. Accurate assessment of motor disorders is essential to guide prognosis and ensure personalized evidence-based interventions., What This Paper Adds: More than half of children and young people with cerebral palsy presented with multiple motor disorders. Dystonia was identified in 60% of study participants. Dystonia was associated with more severe functional impairments and rates of non-motor features., (© 2023 The Authors. Developmental Medicine & Child Neurology published by John Wiley & Sons Ltd on behalf of Mac Keith Press.)

Background: The merits of classifying the heterogeneous group of essential tremors into essential tremor (ET) and essential tremor plus (ETP) are debated., Objectives: We studied the electrophysiological and spiral characteristics of tremor in ET and ETP., Methods: We reviewed standardized videos from a tremor database and clinically classified patients into ET, ETP, or dystonic tremor (DT). The following variables were derived from combined tri-axial accelerometry-surface electromyography (EMG)-peak frequency, total power, peak power, full width half maximum, tremor stability index and EMG-coherence. We analyzed hand-drawn spirals to derive mean deviation, tremor variability, inter-, and intra-loop widths. We compared these variables among the groups., Results: We recruited 72 participants (81.9% male) with mean age 47.7 ± 16.1 years and Fahn-Tolosa-Marin Tremor Rating Scale total score 31.1 ± 14.1. Patients with ET were younger (P = 0.014) and had less severe tremor (P = 0.020) compared to ETP and DT. In ETP group, 48.6% had subtle dystonia. Peak frequency was greater in ETP (7.3 ± 0.3 Hz) compared to DT (6.1 ± 0.4 Hz; P = 0.024). Peak power was greater in ETP and DT for postural tremor. Rest tremor was recordable on accelerometry in 26.7% of ET. Other variables were similar among the groups., Conclusion: Electrophysiological evaluation revealed postural tremor of frequency 6 to 7 Hz in ET, ETP, and DT with subtle differences more severe tremor in ETP and DT, and higher frequency in ETP compared to DT. Our findings suggest a similar tremor oscillator in these conditions, supporting the view that these entities are part of a spectrum of tremor disorders, rather than distinct etiological entities., (© 2023 International Parkinson and Movement Disorder Society.)

This report describes a 15-year-old female with known spastic and dystonic quadriplegic cerebral palsy (CP), Gross Motor Function Classification System IV, and obstructive sleep apnea (OSA). She experienced decreased apneic episodes after receiving onabotulinumtoxin A (BoNT-A) injections for the treatment of oromandibular dystonia (OMD). After her OSA diagnosis, she initially received injections to the bilateral masseter and temporalis muscles with no effect on the frequency of nightly apneic episodes. Subsequently, the bilateral lateral pterygoid muscles were added and she was later noted to have fewer apneic episodes overnight. This case report describes the use of BoNT-A in the muscles of mastication for management of OMD and the ensuing improvement in OSA in a teenager with CP.

We report ATP1A3-associated rapid-onset dystonia-parkinsonism with an atypical presentation including myoclonus and exaggerated startle in four patients. Their prominence over parkinsonism prompted consideration of a syndromic diagnosis of myoclonus dystonia. ATP1α3 dysfunction in GABAergic neurons could explain these examination findings. The spectrum of ATP1A3-associated movement disorders includes myoclonus-dystonia., Competing Interests: Declaration of competing interest No COI., (Copyright © 2023. Published by Elsevier Ltd.)

Hypertonia in childhood may arise because of a variable combination of neuronal and non-neuronal factors. Involuntary muscle contraction may be due to spasticity or dystonia, which represent disorders of the spinal reflex arch and of central motor output respectively. Whilst consensus definitions for dystonia have been established, definitions of spasticity vary, highlighting the lack of a single unifying nomenclature in the field of clinical movement science. The term spastic dystonia refers to involuntary tonic muscle contraction in the context of an upper motor neuron (UMN) lesion. This review considers the utility of the term spastic dystonia, exploring our understanding of the pathophysiology of dystonia and the UMN syndrome. An argument is advanced that spastic dystonia is a valid construct that warrants further exploration. WHAT THIS PAPER ADDS: There is no single universally accepted definitions for terms commonly used to describe motor disorders. Spasticity and dystonia are phenomenologically and pathophysiologically distinct entities. Spastic dystonia represents a subset of dystonia, but with pathophysiological mechanisms more in common with spasticity., (© 2023 Mac Keith Press.)

Background: Myoclonus-dystonia (MD) is a syndrome characterized by subcortical myoclonus and milder dystonia. The main causative gene is the epsilon sarcoglycan gene (SGCE), but other genes may be involved. Response to medications is variable, with poor tolerability limiting their use., Case Presentation: We present the case of a patient with severe myoclonic jerks and mild dystonia since childhood. At first neurological visit at the age of 46 years old, she presented brief myoclonic jerks predominating in the upper limbs and neck, mild at rest and elicited by action, posture and tactile stimulus. Myoclonus was accompanied by mild neck and right arm dystonia. Neurophysiological tests suggested subcortical origin of myoclonus, brain MRI was unremarkable. Myoclonus-dystonia was diagnosed, and genetic testing identified a novel mutation in SGCE gene (c.907delC) in heterozygosis. Over time she assumed a large variety of anti-epileptics without beneficial effect on myoclonus and low tolerability. Add-on treatment with Perampanel was started, with a beneficial effect. No adverse events were reported. Perampanel is the first selective non-competitive AMPA receptor antagonist approved in add-on for focal and generalized tonic-clonic seizures. To our knowledge, this is the first trial of Perampanel in MD., Conclusions: We presented the case of a patient with MD due to SGCE mutation who was treated with Perampanel with beneficial effects. We propose Perampanel as a novel treatment for myoclonus in MD., (© 2023. Fondazione Società Italiana di Neurologia.)

Background: Dystonia is associated with disabling nonmotor symptoms like chronic pain (CP), which is prevalent in dystonia and significantly impacts the quality of life (QoL). There is no validated tool for assessing CP in dystonia, which substantially hampers pain management., Objective: The aim was to develop a CP classification and scoring system for dystonia., Methods: A multidisciplinary group was established to develop the Dystonia-Pain Classification System (Dystonia-PCS). The classification of CP as related or unrelated to dystonia was followed by the assessment of pain severity score, encompassing pain intensity, frequency, and impact on daily living. Then, consecutive patients with inherited/idiopathic dystonia of different spatial distribution were recruited in a cross-sectional multicenter validation study. Dystonia-PCS was compared to validated pain, mood, QoL, and dystonia scales (Brief Pain Inventory, Douleur Neuropathique-4 questionnaire, European QoL-5 Dimensions-3 Level Version, and Burke-Fahn-Marsden Dystonia Rating Scale)., Results: CP was present in 81 of 123 recruited patients, being directly related to dystonia in 82.7%, aggravated by dystonia in 8.8%, and nonrelated to dystonia in 7.5%. Dystonia-PCS had excellent intra-rater (Intraclass Correlation Coefficient - ICC: 0.941) and inter-rater (ICC: 0.867) reliability. In addition, pain severity score correlated with European QoL-5 Dimensions-3 Level Version's pain subscore (r = 0.635, P < 0.001) and the Brief Pain Inventory's severity and interference scores (r = 0.553, P < 0.001 and r = 0.609, P < 0.001, respectively)., Conclusions: Dystonia-PCS is a reliable tool to categorize and quantify CP impact in dystonia and will help improve clinical trial design and management of CP in patients affected by this disorder. © 2023 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society., (© 2023 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.)

Introduction: Cerebral palsy (CP) is a group of permanent disorders attributed to non-progressive disturbances that occurred in the developing fetal or infant brain. Cerebral palsy-like (CP-like) disorders may clinically resemble CP but do not fulfill CP criteria and have often a progressive course and/or neurodevelopmental regression. To assess which patients with dystonic CP and dystonic CP-like disorder should undergo Whole Exome Sequencing (WES), we compared the rate of likely causative variants in individuals regarding their clinical picture, co-morbidities, and environmental risk factors., Method: Individuals with early onset neurodevelopmental disorder (ND) manifesting with dystonia as a core feature were divided into CP or CP-like cohorts based on their clinical picture and disease course. Detailed clinical picture, co-morbidities, and environmental risk factors including prematurity, asphyxia, SIRS, IRDS, and cerebral bleeding were evaluated., Results: A total of 122 patients were included and divided into the CP group with 70 subjects (30 males; mean age 18y5m±16y6m, mean GMFCS score 3.3 ± 1.4), and the CP-like group with 52 subjects (29 males; mean age 17y7m±1y,6 m, mean GMFCS score 2,6 ± 1,5). The WES-based diagnosis was present in 19 (27.1%) CP patients and 30 CP-like patients (57.7%) with genetic conditions overlap in both groups. We found significant differences in diagnostic rate in CP individuals with vs. without risk factors (13.9% vs. 43.3%); Fisher's exact p = 0.0065. We did not observe the same tendency in CP-like (45.5% vs 58.5%); Fisher's exact p = 0.5., Conclusion: WES is a useful diagnostic method for patients with dystonic ND, regardless of their presentation as a CP or CP-like phenotype., Competing Interests: Declarations of competing interest None., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

Background: Hypertrophic olivary degeneration (HOD) is a rare condition caused by lesions within the dentato-rubro-olivary pathway, resulting in ocular nystagmus and palatal myoclonus (oculopalatal tremor) but not usually dystonia. Dystonia is an uncommon association, and we present the first reported association of hypertrophic olivary degeneration with bilateral vocal cord dystonia., Case Presentation: A 33 year old male presented initially with acute hydrocephalus on the background of previous ventriculoperitoneal (VP) shunting for previously treated medulloblastoma. After revision of the VP shunt, the patient developed progressive hiccups and stridor leading to respiratory failure requiring intubation. Ocular pendular nystagmus and palatal myoclonus at 3 Hz was observed. Flexible nasendoscopy (FNE) demonstrated bilateral tonic adduction of the vocal folds with 3 Hz coarse supraglottic, pharyngeal and palatal rhythmic myoclonus. MRI imaging demonstrated T2 hyperintensity within the bilateral inferior olivary nuclei consistent with stage 3 radiological HOD., Conclusions: Dystonia is a rarely reported phenomenon in HOD but is not unexpected with the inferior olivary nucleus implicated in dystonic disorders. We report the association of HOD with bilateral vocal cord adductor dystonia, a potentially life threatening condition., (© 2023. The Author(s).)

Background: Deep Brain Stimulation (DBS) is an established treatment option for refractory dystonia, but the improvement among the patients is variable., Objective: To describe the outcomes of DBS of the subthalamic region (STN) in dystonic patients and to determine whether the volume of tissue activated (VTA) inside the STN or the structural connectivity between the area stimulated and different regions of the brain are associated with dystonia improvement., Methods: The response to DBS was measured by the Burke-Fahn-Marsden Dystonia Rating Scale (BFM) before and 7 months after surgery in patients with generalized isolated dystonia of inherited/idiopathic etiology. The sum of the two overlapping STN volumes from both hemispheres was correlated with the change in BFM scores to assess whether the area stimulated inside the STN affects the clinical outcome. Structural connectivity estimates between the VTA (of each patient) and different brain regions were computed using a normative connectome taken from healthy subjects., Results: Five patients were included. The baseline BFM motor and disability subscores were 78.30 ± 13.55 (62.00-98.00) and 20.60 ± 7.80 (13.00-32.00), respectively. Patients improved dystonic symptoms, though differently. No relationships were found between the VTA inside the STN and the BFM improvement after surgery ( p  = 0.463). However, the connectivity between the VTA and the cerebellum structurally correlated with dystonia improvement ( p  = 0.003)., Conclusions: These data suggest that the volume of the stimulated STN does not explain the variance in outcomes in dystonia. Still, the connectivity pattern between the region stimulated and the cerebellum is linked to outcomes of patients., Competing Interests: The authors have no conflict of interests to declare., (Academia Brasileira de Neurologia. This is an open access article published by Thieme under the terms of the Creative Commons Attribution 4.0 International License, permitting copying and reproduction so long as the original work is given appropriate credit (https://creativecommons.org/licenses/by/4.0/).)

Background: Dystonia is characterized by sustained or intermittent muscle contractions, leading to abnormal posturing and twisting movements. In pediatric patients, dystonia often negatively influences quality of life. Pharmacological treatment for dystonia is often inadequate and causes adverse effects. Deep brain stimulation (DBS) appears to be a valid therapeutic option for pharmacoresistant dystonia in children., Methods: To illustrate the current clinical practice, we hereby describe two pediatric cases of monogenetic movement disorders presenting with dystonia and treated with DBS. We provide a literature review of similar previously described cases and on different clinical aspects of DBS in pediatric dystonia., Results: The first patient, a 6-year-old girl with severe dystonia, chorea, and myoclonus due to an ADCY5 gene mutation, received DBS in an elective setting. The second patient, an 8-year-old boy with GNAO1 -related dystonia and chorea, underwent emergency DBS due to a pharmacoresistant status dystonicus. A significant amelioration of motor symptoms (65% on the Burke-Fahn-Marsden Dystonia Rating Scale) was observed postoperatively in the first patient and her personal therapeutic goals were achieved. DBS was previously reported in five patients with ADCY5 -related movement disorders, of which three showed objective improvement. Emergency DBS in our second patient resulted in the successful termination of his GNAO1 -related status dystonicus, this being the eighth case reported in the literature., Conclusion: DBS can be effective in monogenetic pediatric dystonia and should be considered early in the disease course. To better evaluate the effects of DBS on patients' functioning, patient-centered therapeutic goals should be discussed in a multidisciplinary approach., Competing Interests: M.B. was awarded the TKI-PPP grant in 2021. A.I.B. is the chair of the board of the Dutch Academy of Childhood Disability. J.M.D. was awarded the Netherlands Organization for Health Research and Development grant and a Medtronic grant. J.M.D. is the president of the Netherlands workgroup for Movement Disorders. P.R.S. was awarded consulting fees from Boston Scientific, Medtronic, Elekta and lecture fees from Boston Scientific and Elekta. P.R.S. is the treasurer of the European Society for Stereotactic and Functional Neurosurgery, an associate editor of the Journal of Parkinson's Disease and is in the advisory board of Boston Scientific and Insightec., (The Author(s). This is an open access article published by Thieme under the terms of the Creative Commons Attribution-NonDerivative-NonCommercial License, permitting copying and reproduction so long as the original work is given appropriate credit. Contents may not be used for commercial purposes, or adapted, remixed, transformed or built upon. (https://creativecommons.org/licenses/by-nc-nd/4.0/).)

The aim of this review was to summarise current knowledge regarding hyperkinetic movement disorders related to SARS-CoV-2 infection and vaccination in terms of phenomenology, epidemiology, pathogenesis and treatment. After a thorough review of the PubMed and Google Scholar databases (2020-2022), we identified myoclonus and ataxia sometimes accompanied by opsoclonus (AMS) as the two most frequent COVID-19 sequelae, with chorea, tremor and dystonia being very rare. The pathogenesis seems to be variable, but in the majority of AMS cases it was autoimmunological, with good response and recovery after corticosteroids or intravenous immunoglobulins infusions. Vaccination may be complicated by hyperkinetic movement disorders (e.g. tremor, dystonia), but this is very rare. Patients with Deep Brain Simulation depletion should not be postponed due to lockdowns as this may result in fatal outcomes.

Background: Dystonia is a rare movement disorder, in which patients suffer from involuntary twisting movements or abnormal posturing. Next to these motor symptoms, patients have a high prevalence of psychiatric comorbidity, suggesting a role for serotonin in its pathophysiology. This study investigates the percentage of DNA methylation of the gene encoding for the serotonin reuptake transporter (SLC6A4) in dystonia patients and the associations between methylation levels and presence and severity of psychiatric symptoms., Methods: Patients with cervical dystonia (n = 49), myoclonus dystonia (n = 41) and dopa-responsive dystonia (DRD) (n = 27) and a group of healthy controls (n = 56) were included. Psychiatric comorbidity was evaluated with validated questionnaires. Methylation levels of 20 CpG sites situated 69 to 213 base pairs upstream of the start codon of SLC6A4 were investigated. Methylation in dystonia patients was compared to healthy controls, correcting for age, and correlated with psychiatric comorbidity., Results: Bootstrapped quantile regression analysis showed that being a dystonia patient compared to a healthy control significantly explains the methylation level at two CpG sites (CpG 24: pseudo-R 2  = 0.05, p = 0.04, CpG 32: pseudo-R 2  = 0.14, p = 0.03). Subgroup analysis revealed that being a DRD patient significantly explained a part of the variance of methylation levels at two CpG sites (CpG 21: pseudo-R 2  = 0.03, p = 0.00, CpG 24: pseudo-R 2  = 0.06, p = 0.03). Regression analysis showed that methylation level at CpG 38 significantly explained a small proportion of the variance of severity score for anxiety (R 2  = 0.07, p = 0.04) and having a diagnosis of depression (Nagelkerke R 2 : 0.11, p = 0.00). Genotype of the 5-HTTLPR polymorphism had no additional effect on these associations., Conclusions: This study showed an association between percentage of methylation at several specific sites of the promoter region of SLCA64 and (dopa-responsive) dystonia patients compared to healthy controls. Furthermore, methylation levels were associated with severity of anxiety and presence of a depressive disorder in the dystonia group. This study suggests alterations in the serotonergic metabolism in dystonia patients, and its relation with the non-motor symptoms., (© 2022. The Author(s).)

Introduction: A growing body of evidence highlights the importance of understanding both the sensory and the motor pathophysiology of focal dystonia in order to improve its treatment. This study aims to evaluate somatosensory afferences in patients with focal or segmental dystonia affecting the upper limbs, to analyse whether the dominant limb is more frequently affected, to analyse pain tolerance, and to examine the potential association with pain perception in patients with hand dystonia., Methods: We recruited 24 participants: 12 patients with focal hand dystonia and 12 individuals without dystonia. All participants were evaluated with a digital algometer (Somedic SenseLab AB®, Farsta, Sweden), a Semmes-Weinstein monofilament test, and the visual analogue scale for pain., Results: According to our data, patients showed greater impairment in surface sensitivity than controls, both in the dominant and the non-dominant hands, as well as greater presence of pain (P > .001). Furthermore, the dystonia group showed a negative correlation between perceived pain and pressure pain tolerance threshold (rho = -0.83; P < .001)., Conclusions: Patients with focal hand dystonia presented alterations in sensitivity and more severe perceived pain than individuals without dystonia. Future studies with larger samples should aim to analyse the clinical implications and everyday impact of both objective and subjective pain., (Copyright © 2020 Sociedad Española de Neurología. Published by Elsevier España, S.L.U. All rights reserved.)

Background: Spasticity and dyskinesia are motor signs that co-exist in cerebral palsy (CP). It is well accepted that, in spastic bilateral CP, dystonia can be present in addition to spasticity, and equally that spasticity is often present in individuals with dyskinetic CP. In unilateral spastic CP, dystonia of the upper extremity is only rarely identified or addressed. The aim of this study was to investigate if dystonia was present in the hand of children with unilateral spastic CP, and, if present, to what extent, and when it was first noticeable., Method: Ninety-seven children with unilateral spastic CP, born 1999-2014, with standardized digital films of hand function from Assisting Hand Assessments (AHA), were included. Films were reviewed, and presence or absence, of dystonia and choreoathetosis were scored by three experienced raters., Results: Dystonia in the hand was present during activities in 70% (68/97) of the children at a mean age of 12 years (SD 4,4). In 74% (50/68) of these children, dystonia was present more than 50% of the evaluated time. For 63% (43/68) more than one digital recording at younger ages were available. Dystonia could first clearly be observed at a mean age of 3,8 years. Choreoathetosis was observed in 7% (5/68) of the children with dystonia. Children without dystonia had significantly higher (corresponding to better function) AHA units (median: 75, 25th - 75th: 45-82) in comparison to children with dystonia (median: 57, 25th - 75th: 52-63) (p = 0.01)., Conclusion: Dystonia in the hand is common in unilateral CP and correlates to lower hand functioning., Competing Interests: Declaration of competing interest All authors have agreed to the final version of the manuscript. There are no conflicts of interest and no sponsor have been involved in any part of this research., (Copyright © 2022. Published by Elsevier Ltd.)

Introduction: The recently released classification has revised the nosology of tremor, defining essential tremor (ET) as a syndrome and fueling an enlightened debate about some newly conceptualized entities such as ET-plus. As a result, precise information of demographics, clinical features, and about the natural history of these conditions are lacking., Methods: The ITAlian tremor Network (TITAN) is a multicenter data collection platform, the aim of which is to prospectively assess, according to a standardized protocol, the phenomenology and natural history of tremor syndromes., Results: In the first year of activity, 679 patients have been recruited. The frequency of tremor syndromes varied from 32% of ET and 41% of ET-plus to less than 3% of rare forms, including focal tremors (2.30%), task-specific tremors (1.38%), isolated rest tremor (0.61%), and orthostatic tremor (0.61%). Patients with ET-plus were older and had a higher age at onset than ET, but a shorter disease duration, which might suggest that ET-plus is not a disease stage of ET. Familial aggregation of tremor and movement disorders was present in up to 60% of ET cases and in about 40% of patients with tremor combined with dystonia. The body site of tremor onset was different between tremor syndromes, with head tremor being most commonly, but not uniquely, associated with dystonia., Conclusions: The TITAN study is anticipated to provide clinically relevant prospective information about the clinical correlates of different tremor syndromes and their specific outcomes and might serve as a basis for future etiological, pathophysiological, and therapeutic research., (© 2022. The Author(s).)

Background: Status dystonicus is a life-threatening, underrecognized movement disorder emergency. We aimed to ascertain the etiology, clinical presentation, complications, and outcomes of status dystonicus in children and reviewed the literature for similar studies. Methods: Records of all children aged <14 years admitted to a single center with status dystonicus between 2014 and 2018 were reviewed. Results: Twenty-four children (75% male) were identified with status dystonicus. The annual incidence rate was 0.05 per 1000 new admissions <12 years of age. The mean age at presentation was 6.3 ± 3.6 years. Median duration of hospital stay was 10.5 days (interquartile range 5-21.7). The severity of dystonia at presentation was grade 3 (n = 9; 37.5%) and 4 (n = 9; 37.5%). The most common triggering factor was intercurrent illness/infection (n = 18; 75%). The most common underlying etiologies were cerebral palsy (n = 8; 33.3%), complicated tubercular meningitis (n = 3; 12.5%), and mitochondrial disorders (n = 3; 12.5%). Basal ganglia involvement was seen in 15 cases (62.5%). Respiratory and/or bulbar compromise (n = 20; 83.3%) and rhabdomyolysis (n = 15; 62.5%) were most commonly seen. Oral trihexyphenidyl (96%) followed by oral or intravenous diazepam (71%), oral baclofen (67%), and midazolam infusion (54%) were the most common drugs used. Clonidine was used in 33% cases, without any significant side effects. Three children died owing to refractory status dystonicus and its complications; the mortality rate was 12.5%. Conclusion Status dystonicus is a neurologic emergency in children with severe dystonia, with significant complications and a high mortality rate. Static and acquired disorders are more common than heredo-familial causes. Identification and treatment of infection in children is important as the majority of cases are triggered by an intercurrent infection.

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.)

The links between the two archetypical basal ganglia disorders, dystonia and parkinsonism, are manifold and stem from clinical observations, imaging studies, animal models and genetics. The combination of both, i.e. the syndrome of dystonia-parkinsonism, is not uncommonly seen in movement disorders clinics and has a myriad of different underlying aetiologies, upon which treatment and prognosis depend. Based on a comprehensive literature review, we delineate the clinical spectrum of disorders presenting with dystonia-parkinsonism. The clinical approach depends primarily on the age at onset, associated neurological or systemic symptoms and neuroimaging. The tempo of disease progression, and the response to L-dopa are further important clues to tailor diagnostic approaches that may encompass dopamine transporter imaging, CSF analysis and, last but not least, genetic testing. Later in life, sporadic neurodegenerative conditions are the most frequent cause, but the younger the patient, the more likely the cause is unravelled by the recent advances of molecular genetics that are focus of this review. Here, knowledge of the associated phenotypic spectrum is key to guide genetic testing and interpretation of test results. This article is part of the Special Issue "Parkinsonism across the spectrum of movement disorders and beyond" edited by Joseph Jankovic, Daniel D. Truong and Matteo Bologna., (Copyright © 2021 Elsevier B.V. All rights reserved.)

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.)

Introduction: Dystonia is a movement disorder presented with involuntary muscle contraction causing abnormal posture, movement, or both. Besides motor symptoms, patients may also report non-motor symptoms such as pain, anxiety, apathy, depression, sleep problems, fatigue, and cognitive impairment. The etiology of fatigue in patients with dystonia is not yet well understood., Aim: To evaluate the presence of fatigue, depression, anxiety, sleep disorders, and daily sleepiness in patients with focal and segmental dystonia and to determine which of these non-motor symptoms influence the occurrence and severity of fatigue., Patients and Methods: Patients were surveyed for symptoms of fatigue, depression, anxiety, night-time sleep problems, and daily sleepiness using the Fatigue Assessment Scale, Beck Depression Inventory II, Beck Anxiety Inventory, Pittsburgh Sleep Questionnaire Index, and Epworth Sleepiness Scale. Demographic data (sex, age, and disease duration) were collected from patient medical records. On statistical analysis, we used SPSS for Windows 10. The level of significance was set at p<0.05., Results: Sixty patients (43 female and 17 male) with focal or segmental dystonia were evaluated. Fatigue was reported by 67.2% of patients. Fatigue (general, physical, and mental fatigue) was found to correlate with depression, anxiety, and sleep problems. Daily sleepiness correlated only with mental fatigue. Disease duration, age, and gender did not influence the symptoms of fatigue. Multiple regression analysis showed that depression mostly predicted symptoms of general, physical, and mental fatigue., Conclusion: Depression mostly predicted symptoms of general, physical, and mental fatigue in patients with focal and segmental dystonia., (© 2021. Fondazione Società Italiana di Neurologia.)

Background: It has been debated for decades whether primary writing tremor is a form of dystonic tremor, a variant of essential tremor, or a separate entity. We wished to test the hypothesis that primary writing tremor and dystonia share a common pathophysiology., Objectives: The objective of the present study was to investigate the pathophysiological hallmarks of dystonia in patients affected by primary writing tremor., Methods: Ten patients with idiopathic dystonic tremor syndrome, 7 with primary writing tremor, 10 with essential tremor, and 10 healthy subjects were recruited. They underwent eyeblink classic conditioning, blink recovery cycle, and transcranial magnetic stimulation assessment, including motor-evoked potentials and short- and long-interval intracortical inhibition at baseline. Transcranial magnetic stimulation measures were also recorded after paired-associative plasticity protocol., Results: Primary writing tremor and dystonic tremor syndrome had a similar pattern of electrophysiological abnormalities, consisting of reduced eyeblink classic conditioning learning, reduced blink recovery cycle inhibition, and a lack of effect of paired-associative plasticity on long-interval intracortical inhibition. The latter 2 differ from those obtained in essential tremor and healthy subjects. Although not significant, slightly reduced short-interval intracortical inhibition and a larger effect of paired-associative plasticity in primary writing tremor and dystonic tremor syndrome, compared with essential tremor and healthy subjects, was observed., Conclusions: Our initial hypothesis of a common pathophysiology between dystonia and primary writing tremor has been confirmed. Primary writing tremor might be considered a form of dystonic tremor. © 2021 International Parkinson and Movement Disorder Society., (© 2021 International Parkinson and Movement Disorder Society.)

The clinical presentation of bilateral perisylvian polymicrogyria (PMG) is highly variable, including oromotor dysfunction, epilepsy, intellectual disability, and pyramidal signs. Extrapyramidal features are extremely rare. We present four apparently unrelated patients with a unique association of PMG with dystonia. The clinical, genetic, and radiologic features are described and possible mechanisms of dystonia are discussed. All patients were female and two were born to consanguineous families. All presented with early childhood onset dystonia. Other neurologic symptoms and signs classically seen in bilateral perisylvian PMG were observed, including oromotor dysfunction and speech abnormalities ranging from dysarthria to anarthria (4/4), pyramidal signs (3/4), hypotonia (3/4), postnatal microcephaly (1/4), and seizures (1/4). Neuroimaging showed a unique pattern of bilateral PMG with an infolded cortex originating primarily from the perisylvian region in three out of four patients. Whole exome sequencing was performed in two out of four patients and did not reveal pathogenic variants in known genes for cortical malformations or movement disorders. The dystonia seen in our patients is not described in bilateral PMG and suggests an underlying mechanism of impaired connectivity within the motor network or compromised cortical inhibition. The association of bilateral PMG with dystonia in our patients may represent a new neurogenetic disorder., (© 2020 Wiley Periodicals LLC.)

Pediatric arterial ischemic stroke involving the basal ganglia and/or thalamus is one of the most common causes of dystonia in children. Dystonia is a movement disorder in which excessive, involuntary muscle contractions result in twisting or repetitive movements, and abnormal posturing. The basal ganglia have been implicated in mood functioning and difficulties in these domains have been noted in adults with dystonia, yet little is currently known about these outcomes in children with dystonia following stroke. The objective of this study was to explore mental health outcomes in children with basal ganglia stroke and to determine whether children with post-stroke dystonia experience additional mental health difficulties. We also examined associations between mental health, cognitive, and motor outcomes. Participants were 75 children with stroke involving the basal ganglia and/or thalamus (dystonia n = 24, no dystonia n = 51). Results supported the presence of greater levels of anxiety and depression symptoms in children with post-stroke dystonia after stroke relative to those with similar patterns of stroke, but no dystonia. There were no significant associations between motor, cognitive, and mental health outcomes in children with post-stroke dystonia aside from depression and behavioral regulation. Motor and cognitive outcome were significantly associated in the stroke only group. These findings suggest maladaptive reorganization after stroke may contribute to motor, cognitive, and mental health outcomes in children with post-stroke dystonia, and that these outcomes are independent from one another.

Background: Unilateral or very asymmetric upper limb tremors with a jerky appearance are poorly investigated. Their clinical classification is an unsolved problem because their classification as essential tremor versus dystonic tremor is uncertain. To avoid misclassification as essential tremor or premature classification as dystonic tremor, the term indeterminate tremor was suggested., Objectives: The aim of this study was to characterize this tremor subgroup electrophysiologically and evaluate whether diagnostically meaningful electrophysiological differences exist compared to patients with essential tremor and dystonic tremor., Methods: We enrolled 29 healthy subjects and 64 patients with tremor: 26 with dystonic tremor, 23 with essential tremor, and 15 patients with upper limb tremor resembling essential tremor but was unusually asymmetric and jerky (indeterminate tremor). We investigated the somatosensory temporal discrimination threshold, the short-interval intracortical inhibition, and the cortical plasticity by paired associative stimulation., Results: Somatosensory temporal discrimination threshold was significantly increased in patients with dystonic tremor and indeterminate tremor, but it was normal in the essential tremor patients and healthy controls. Significant differences in short-interval intracortical inhibition and paired associative stimulation were not found among the three patient groups and controls., Conclusion: These results indicate that indeterminate tremor, as defined in this study, shares electrophysiological similarities with dystonic tremor rather than essential tremor. Therefore, we propose that indeterminate tremor should be considered as a separate clinical entity from essential tremor and that it might be dystonic in nature. Somatosensory temporal discrimination appears to be a useful tool in tremor classification. © 2019 International Parkinson and Movement Disorder Society., (© 2019 International Parkinson and Movement Disorder Society.)

Objectives: To systematically investigate the relationship between motor and non-motor symptoms, and health-related quality of life (HR-QoL) in children and young adults with dystonia., Methods: In this prospective observational cross-sectional study, 60 patients (6-25 years) with childhood-onset dystonia underwent a multidisciplinary assessment of dystonia severity (Burke-Fahn-Marsden Dystonia Rating Scale, Global Clinical Impression), motor function (Gross Motor Function Measure, Melbourne Assessment of Unilateral Upper Limb Function), pain (visual analogue scale), intelligence (Wechsler Intelligence Scale), executive functioning (Behavior Rating Inventory of Executive Function) and anxiety/depression (Child/Adult Behavior Checklist). Measures were analyzed using a principal component analysis and subsequent multiple regression to evaluate which components were associated with HR-QoL (Pediatric Quality of life Inventory) for total group, and non-lesional (primary) and lesional (secondary) subgroups., Results: Patients (29 non-lesional, 31 lesional dystonia) had a mean age of 13.6 ± 5.9 years. The principal component analysis revealed three components: 1) motor symptoms; 2) psychiatric and behavioral symptoms; and 3) pain. HR-QoL was associated with motor symptoms and psychiatric and behavioral symptoms (R 2  = 0.66) for the total sample and lesional dystonia, but in the non-lesional dystonia subgroup only with psychiatric and behavioral symptoms (R 2  = 0.51)., Conclusions: Non-motor symptoms are important for HR-QoL in childhood-onset dystonia. We suggest a multidisciplinary assessment of motor and non-motor symptoms to optimize individual patient management., (Copyright © 2018. Published by Elsevier Ltd.)

Case: An adolescent girl presented with an atypical scoliotic curve, pelvic obliquity, back pain, and lower-extremity paresthesias. A workup revealed generalized primary torsion dystonia. The condition was refractory to medical treatment and necessitated implantation of a deep brain stimulator. The scoliosis required operative correction, and the patient underwent posterior spinal arthrodesis with hook-rod instrumentation, which resulted in successful correction through 7 years of follow-up., Conclusion: The differential diagnosis for adolescent scoliosis should include dystonia as a potential cause, especially when a patient presents with muscular contractures, an atypical scoliotic curve, pelvic obliquity, or changing curve characteristics.

Cervical dystonia (CD) affects the musculature of the neck in a focal way or associated to other parts of the body. The aim of this study was to identify clinical differences between patients with dystonia patients without family history and with family history (sporadic). Eighty-eight patients with CD were recruited in a Movement Disorders Clinic between June of 2008 and June of 2009. Only patients with no etiological diagnosis were accepted for analysis. The age of onset of symptoms was later in patients with focal and segmental dystonia than in patients with generalized dystonia (p<0.001). The severity of symptoms was higher in patients with sporadic dystonia than in familial patients (p<0.01). Generalized cases were more severe in patients with a family history (p<0.01). Sporadic patients had higher levels of pain than familial cases (p<0.05). We expect soon to present the results of genetic analyzes of these patients.

With the increasing understanding of the involvement of basal ganglia circuits in the functions of movement, cognition, emotion and motivation, the network model of dystonia posits a plausible mechanism for the co-occurrence of mental dysfunctions in dystonia-plus syndromes. Genetic mutations that alter the production of neurotransmitters and receptors can potentially affect the function of these interconnecting circuits and yield non-motor symptoms as well. This article reviews the psychiatric findings in dystonia-plus syndromes reported thus far in the literature, both in animal models and human subjects. Based on this innovative understanding of the pathophysiology, implications to treatment of combined motor and non-motor symptoms (i.e. mental dysfunctions) are also briefly discussed.

Dystonia is characterized by muscle contractions leading to abnormal postures with involuntary twisting and repetitive movements. Inherited dystonia designated by DYT locus symbols can be separated into three broad phenotypic categories: primary torsion dystonia (PTD), where dystonia is the only clinical sign (except for tremor) (DYT1, 2, 4, 6, 7, 13, 17, and 21); dystonia plus loci, where other phenotypes in addition to dystonia, including parkinsonism or myoclonus, are present (DYT3, 5/14, 11, 12, 15, and 16); and paroxysmal forms of dystonia/dyskinesia (DYT8, 9, 10, 18, 19, and 20). Currently, 19 loci including 10 genes have been identified for inherited dystonias. In this review, the phenotypes associated with these loci and the responsible genes will be discussed., (© Thieme Medical Publishers.)

Oppenheim's or DYT1 dystonia is a primary dystonia typically presenting in a limb at an early age and usually becoming generalised within 5 years. Over the last decade research into this debilitating disorder has progressed considerably, enabling the identification of a genetic lesion (a 3bp deletion in the DYT1 gene) now widely accepted as the cause of a majority of cases. This case report presents the first molecularly diagnosed pedigree of an Australian family with DYT1 dystonia, which presented as writer's cramp in the 15-year-old proband and two of his cousins.

Sensory processing is impaired in focal hand dystonia (FHD), with most previous studies having evaluated only the symptomatic limb. The purpose of this study was to establish whether the sensory system is affected in other types of dystonias and whether the contralateral hand is also involved in FHD. We used a spatial acuity measure (Johnson-Van Boven-Phillips domes) to evaluate sensory spatial discrimination in both hands of patients with different forms of dystonias including primary generalized DYT1 dystonia (associated with a unique deletion in the DYT1 gene) (n = 13), FHD (n = 15), benign essential blepharospasm (n = 9), cervical dystonia (n = 10) and in age-matched controls. Clinical evaluation included the Fahn dystonia scale for the focal dystonia groups and the Marsden-Burke-Fahn scale for the generalized dystonia group. Spatial discrimination was normal in patients with DYT1 dystonia, despite all of these patients having hand dystonia. However, spatial discrimination thresholds were significantly increased in both hands in the focal dystonia groups (thresholds were similar for each group) and did not correlate significantly with either severity or duration of dystonic symptoms. Thresholds were significantly increased in the dominant hand compared with the non-dominant hand only within the FHD group. Our observations demonstrate involvement of both the dominant and non-dominant somatosensory cortices, and suggest that abnormal sensory processing is a fundamental disturbance in patients with focal dystonia. These findings of altered sensory processing in idiopathic focal but not generalized DYT1 dystonia suggest both a primary pathophysiological role for the phenomenon in focal dystonia and divergent pathophysiological processes in the two conditions.