Epidemiology of primary dystonia

Long-term Efficacy of Bilateral Globus Pallidus Stimulation in the Treatment of Meige Syndrome

OBJECTIVE

This study aimed to investigate the long-term efficacy and prognosis of bilateral globus pallidus internus (GPi) deep brain stimulation (DBS) in patients with benign essential blepharospasm (BEB) and complete Meige syndrome, and to search for the best therapeutic subregion within the GPi.

MATERIALS AND METHODS

Data were collected for 36 patients with Meige syndrome who underwent bilateral GPi-DBS surgery at our hospital between March 2014 and February 2022. Using the Burk-Fahn-Marsden Dystonia Rating Scale (BFMDRS)-Movement (BFMDRS-M) and BFMDRS-Disability (BFMDRS-D), the severity of the symptoms of patients with complete Meige syndrome was evaluated before surgery and at specific time points after surgery. Patients with BEB were clinically evaluated for the severity of blepharospasm using BFMDRS-M, the Blepharospasm Disability Index (BDI), and Jankovic Rating Scale (JRS). Three-dimensional reconstruction of the GPi-electrode was performed in some patients using the lead-DBS software, and the correlation between GPi subregion volume of tissue activated (VTA) and symptom improvement was analyzed in patients six months after surgery. The follow-up duration ranged from six to 99 months.

RESULTS

Compared with preoperative scores, the results of all patients at six months after surgery and final follow-up showed a significant decrease (p < 0.05) in the mean BFMDRS-M score. Among them, the average BFMDRS-M improvement rates in patients with BEB at six months after surgery and final follow-up were 60.3% and 69.7%, respectively, whereas those in patients with complete Meige syndrome were 54.5% and 58.3%, respectively. The average JRS and BDI scores of patients with BEB also decreased significantly (p < 0.05) at six months after surgery and at the final follow-up (JRS improvement: 38.6% and 49.1%, respectively; BDI improvement: 42.6% and 57.4%, respectively). We were unable to identify significantly correlated prognostic factors. There was a significant correlation between GPi occipital VTA and symptom improvement in patients at six months after surgery (r = 0.34, p = 0.025).

CONCLUSIONS

Our study suggests that bilateral GPi-DBS is an effective treatment for Meige syndrome, with no serious postoperative complications. The VTA in the GPi subregion may be related to the movement score improvement. In addition, further research is needed to predict patients with poor surgical outcomes.

Assessment and Treatment of Abnormal Involuntary Movements: A Clinically Focused Narrative Review

LEARNING OBJECTIVES

After participating in this CME activity, the psychiatrist should be better able to:• Categorize and describe different types of abnormal involuntary movements (AIMs).• Identify assessment tools and treatment options for AIMs.

ABSTRACT

Abnormal involuntary movements (AIMs) comprise a diverse group of movement disorders characterized by uncontrolled and unintended movements (e.g., tremors, tics, dystonia). AIMs can occur at any stage of life and pose significant challenges for clinicians. It is difficult to determine their underlying causes due to the complex neurobiological mechanisms involved. Therefore, it is crucial to quantify the severity and progression of AIMs using well-validated measurement scales, such as the Abnormal Involuntary Movement Scale (AIMS). By employing reliable assessment approaches, clinicians can objectively evaluate the motoric manifestations of AIMs and track them over time. Treatment of AIMs varies depending on their nature and etiology. While AIMs often respond to treatment, serious side effects can undermine treatment efficacy. In this clinically focused narrative review, we categorize different types of AIMs and discuss their neurobiological aspects. Further, we emphasize the importance of using well-validated measurement scales for accurate assessment and discuss available treatment modalities that target the specific AIMs manifestations. Additionally, we cover the need for comprehensive care to address the multifaceted nature of AIMs, accounting for their physical manifestations as well as their psychological, social, and functional toll on patients. By embracing a multidisciplinary approach, health care professionals can provide patient-centered care that promotes overall well-being and enhances the lives of patients coping with AIMs. Regular follow-up assessments are necessary to monitor treatment response, adjust medications when needed, and provide ongoing support for individuals affected by AIMs.

Does sex influence the natural history of idiopathic adult-onset dystonia?

BACKGROUND

Several earlier studies showed a female predominance in idiopathic adult-onset dystonia (IAOD) affecting the craniocervical area and a male preponderance in limb dystonia. However, sex-related differences may result from bias inherent to study design. Moreover, information is lacking on whether sex-related differences exist in expressing other dystonia-associated features and dystonia spread.

OBJECTIVE

To provide accurate information on the relationship between sex differences, motor phenomenology, dystonia-associated features and the natural history of IAOD.

METHODS

Data of 1701 patients with IAOD from the Italian Dystonia Registry were analysed.

RESULTS

Women predominated over men in blepharospasm, oromandibular, laryngeal and cervical dystonia; the sex ratio was reversed in task-specific upper limb dystonia; and no clear sex difference emerged in non-task-specific upper limb dystonia and lower limb dystonia. This pattern was present at disease onset and the last examination. Women and men did not significantly differ for several dystonia-associated features and tendency to spread. In women and men, the absolute number of individuals who developed dystonia tended to increase from 20 to 60 years and then declined. However, when we stratified by site of dystonia onset, different patterns of female-to-male ratio over time could be observed in the various forms of dystonia.

CONCLUSIONS

Our findings provide novel evidence on sex as a key mediator of IAOD phenotype at disease onset. Age-related sexual dimorphism may result from the varying exposures to specific age-related and sex-related environmental risk factors interacting in a complex manner with biological factors such as hormonal sex factors.

[Pain and cervical dystonia]

BACKGROUND

Dystonia is a hyperkinetic movement disorder that results in twisting, cramps and tremors due to sustained or intermittent muscle contractions. Cervical dystonia is the most common form of dystonia, in which the head, neck and/or shoulder areas are affected. In addition to these motor symptoms, pain and psychiatric symptoms are frequent in (cervical) dystonia.

OBJECTIVE

Description of the incidence and evaluation of pain in cervical dystonia, summary and discussion of treatment options and effects.

MATERIAL AND METHODS

In this review article the results in the scientific literature on pain in dystonia are summarized and discussed.

RESULTS

Compared to other forms of dystonia, pain occurs most frequently in patients with cervical dystonia. A large proportion of patients with cervical dystonia suffer from pain, which contributes most to impairment of the patient. The motor symptoms of dystonia are usually treated with botulinum toxin injections. These have a muscle relaxing effect and also relieve pain. The study situation on the occurrence and treatment of pain in other forms of dystonia is so far very limited. Pain can dominate the clinical picture in patients with cervical dystonia. Evaluation of pain in cervical dystonia can be performed using standardized questionnaires.

CONCLUSION

It is important to ask patients with cervical dystonia about pain and to consider it in treatment planning and evaluation. Vice versa, if pain is present the possibility of a causative dystonia should also be considered. For pain assessment there are some newly developed questionnaires to assess pain in a standardized way in patients with dystonia. Further research is needed to better understand the pathomechanisms of pain in dystonia.

The effect on blink frequency of a selective blue-filtering photochromic lens in patients with benign essential blepharospasm

Objective

The aim of this clinical study was to assess the impact of a non-invasive selective blue-filtering photochromic lens coating Crizal Prevencia on the treatment and response of benign essential blepharospasm (BEB).

Patients and methods

Twenty-four patients were recruited in the outpatient clinic of the Medical University of Vienna in a randomized, double-blind, cross-over study design. Blink frequencies were assessed in patients with BEB before and 14 days after intervention with either a filtering ophthalmic lens or a placebo lens, respectively. Outcome parameters include sub-group analysis of a blink frequency under six different conditions: three photopic conditions, one resting condition, one reading condition, and one video game condition.

Results

From 24 recruited patients, 15 patients were available for final analysis. Comparing the optical blue filtering lens to placebo, showed a reduced blink frequency in specific subtests, but not compared to baseline.

Discussion

In conclusion, optical filtering glasses might have a beneficial effect on BEB and provide a non-invasive therapeutic add-on option, in addition to botulinum neurotoxin therapy, for patients with BEB and should necessarily be further investigated in a multicenter setting, resulting in larger sample sizes to gain valid information about the effect of photochromic blue filter glasses in BEB.Clinical trial registration: https://drks.de/search/en/trial/DRKS00032135, DRKS00032135.

Black and hispanic patients with movement disorders less likely to undergo deep brain stimulation

BACKGROUND

DBS is an effective surgical treatment for ET, PD, and dystonia. Racial disparities in DBS utilization in PD have been documented demonstrating that Black patients receive DBS at lower rates than White patients. To our knowledge, no studies have investigated if this pattern of non-use persists in other movement disorders with FDA-approval.

OBJECTIVE

To identify racial and ethnic disparities in DBS utilization in those hospitalized for ET, PD, and dystonia.

METHODS

The NIS database was queried for US hospitalizations from 2012 to 2018 with a primary diagnosis of ET, PD, or dystonia, and a total of 3,363, 21,963, and 1,835 discharges were recorded, respectively. Within that sample, treatment with DBS was identified. Sex, race, age, payment method, income quartile, year, mortality risk, hospital size, urban/rural setting, teaching status, and geographic region were extracted. A multivariate logistic regression was performed to identify predictors for use and non-use of DBS.

RESULTS

Between 2012 and 2018, Black patients with PD, ET, and dystonia were less likely to receive DBS than White patients. Black patients with PD were 7 times less likely to receive DBS (OR = 0.145, CI = 0.111-0.189), and Black patients with ET and dystonia were 5 times less likely to receive DBS than White patients (OR = 0.188, CI = 0.124-0.285; OR = 0.186, CI = 0.084-0.414). Compared to White patients, Hispanic patients with PD (OR = 0.631, OR = 0.539-0.740) and ET (OR = 0.438, CI = 0.277-0.695) were less likely to undergo DBS. When controlling for patient and hospital level characteristics, racial and ethnic disparities remained.

CONCLUSIONS

Our data suggest that Black patients with a diagnosis of ET, PD, or dystonia and Hispanic patients with a diagnosis of ET or PD were less likely to be treated with DBS than White patients between 2012 and 2018.

Early-onset inherited dystonias versus late-onset idiopathic dystonias: Same or different biological mechanisms?

Dystonia syndromes encompass a heterogeneous group of movement disorders which might be differentiated by several clinical-historical features. Among the latter, age-at-onset is probably the most important in predicting the likelihood both for the symptoms to spread from focal to generalized and for a genetic cause to be found. Accordingly, dystonia syndromes are generally stratified into early-onset and late-onset forms, the former having a greater likelihood of being monogenic disorders and the latter to be possibly multifactorial diseases, despite being currently labeled as idiopathic. Nonetheless, there are several similarities between these two groups of dystonia, including shared pathophysiological and biological mechanisms. Moreover, there is also initial evidence of age-related modifiers of early-onset dystonia syndromes and of critical periods of vulnerability of the sensorimotor network, during which a combination of genetic and non-genetic insults is more likely to produce symptoms. Based on these lines of evidence, we reappraise the double-hit hypothesis of dystonia, which would accommodate both similarities and differences between early-onset and late-onset dystonia in a single framework.

Evaluation of Blepharoptosis in Patients With Refractory Blepharospasm by VISA-Video Recordings, Idiosyncratic Expressions, Sensory Tricks, and Ancillary Procedures

BACKGROUND

How to evaluate blepharoptosis concomitantly presented with refractory and uncontrollable blepharospasm? To date, there is a paucity of publications on the ideal evaluation methods. An innovative method-video recordings, idiosyncratic facial expressions, sensory tricks, and ancillary procedures (VISA)-is developed for preoperative evaluation, and the surgical outcomes are demonstrated.

METHODS

A retrospective study using VISA for blepharoptosis evaluation was conducted on 51 patients with refractory blepharospasm. Based on the evaluation, patients underwent blepharoptosis correction simultaneously besides the selective myectomy and myotomy in situ of the eyelid protractors for blepharospasm. Preoperative and postoperative palpebral fissure height, margin reflex distance 1, ptosis severity, and levator function were assessed to identify the effectiveness of VISA. All the procedures were performed by the senior author C.-S.L.

RESULTS

There were 42 patients diagnosed with essential blepharospasm and 9 patients with Meige syndrome. Forty-one patients (82/102 eyelids [80.4%]) had concomitant blepharoptosis and blepharospasm. Ptosis severity was mild in 21 eyelids (25.6%), moderate in 12 eyelids (14.6%), and severe in 49 eyelids (59.8%). Preoperative/postoperative (6 months) values of palpebral fissure height, margin reflex distance 1, and levator function were 4.70 ± 2.45 mm/8.35 ± 1.33 mm (P < 0.05), -0.30 ± 3.19 mm/3.73 ± 1.05 mm (P < 0.05), and 13.07 ± 2.56 mm/13.68 ± 2.34 mm (P < 0.05), respectively. Undercorrection and revision rate reported 9.8% and 3.7%, individually.

CONCLUSIONS

VISA approach overcomes the difficulty of blepharoptosis assessment in patients with refractory blepharospasm. It provides useful preoperative information required for adequate blepharoptosis correction in blepharospasm surgery and yielded desirable outcomes.

Dystonias: Clinical Recognition and the Role of Additional Diagnostic Testing

Dystonia is the third most common movement disorder, characterized by abnormal, frequently twisting postures related to co-contraction of agonist and antagonist muscles. Diagnosis is challenging. We provide a comprehensive appraisal of the epidemiology and an approach to the phenomenology and classification of dystonia, based on the clinical characteristics and underlying etiology of dystonia syndromes. We discuss the features of common idiopathic and genetic forms of dystonia, diagnostic challenges, and dystonia mimics. Appropriate workup is based on the age of symptom onset, rate of progression, whether dystonia is isolated or combined with another movement disorder or complex neurological and other organ system eatures. Based on these features, we discuss when imaging and genetic should be considered. We discuss the multidisciplinary treatment of dystonia, including rehabilitation and treatment principles according to the etiology, including when pathogenesis-direct treatment is available, oral pharmacological therapy, chemodenervation with botulinum toxin injections, deep brain stimulation and other surgical therapies, and future directions.

Global Epidemiology of Movement Disorders: Rare or Underdiagnosed?

In this manuscript, we review the epidemiology of movement disorders including Parkinson's disease (PD), atypical parkinsonism, essential tremor, dystonia, functional movement disorders, tic disorders, chorea, and ataxias. We emphasize age-, sex-, and geography-based incidence and prevalence, as well as notable trends including the rising incidence and prevalence of PD. Given the growing global interest in refining clinical diagnostic skills in recognizing movement disorders, we highlight some key epidemiological findings that may be of interest to clinicians and health systems tasked with diagnosing and managing the health of patients with movement disorders.

Frequency of Hemorrhagic Side Effects of Botulinum Neurotoxin Treatment in Patients with Blepharospasm and Hemifacial Spasm on Antithrombotic Medication

The aim of this study was to investigate the frequency of hemorrhagic side effects of botulinum neurotoxin A injections (BoNT/A) for the treatment of benign essential blepharospasm (BEB) and hemifacial spasm (HFS) in patients taking antithrombotic drugs (ATD). A total of 140 patients were included (female: 65%; BEB: 75%; mean age: 70 ± 12 years). According to their current antithrombotic medication, participants were either assigned to the ATD group (41%), or to the control group (59%). The ATD group was further divided into subgroups depending on the medication administered: acetylsalicylic acid, ADP receptor antagonists, direct oral anticoagulants, vitamin-K antagonists, or dual antiplatelet therapy. The frequency of hemorrhagic side effects was recorded by retrospective analysis of past treatments as documented in the patient's file set in relation to the number of past treatments (hematoma frequency of past treatments, HF_retro) as well as by a prospective survey capturing the side effects of one single treatment (hematoma frequency of actual treatment, HF_actual). There was no significant difference in hematoma frequency between the ATD group and the control group, neither for past (HF_retro: ATD: 2%; 45/2554; control: 4%; 109/2744) nor for the current BoNT/A treatments (HF_actual: ATD: 30%; 16/53; control: 31%; 22/72). Even between ATD subgroups, hematoma frequency did not differ significantly. Overall, hemorrhagic side effects of the BoNT/A treatment for BEB and HFS were mild and non-disabling.

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.

Neuropsychological Functioning in Primary Dystonia: Updated and Expanded Multidomain Meta-Analysis

BACKGROUND

Primary dystonia is conventionally considered as a motor disorder, though an emerging literature reports associated cognitive dysfunction.

OBJECTIVES

Here, we conducted meta-analyses on studies comparing clinical measures of cognition in persons with primary dystonia and healthy controls (HCs).

METHODS

We searched PubMed, Embase, Cochrane Library, Scopus, and PsycINFO (January 2000-October 2020). Analyses were modeled under random effects. We used Hedge's g as a bias-corrected estimate of effect size, where negative values indicate lower performance in dystonia versus controls. Between-study heterogeneity and bias were primarily assessed with Cochran's Q, I² , and Egger's regression.

RESULTS

From 866 initial results, 20 studies met criteria for analysis (dystonia n = 739, controls n = 643; 254 effect sizes extracted). Meta-analysis showed a significant combined effect size of primary dystonia across all studies (g = -0.56, P < 0.001), with low heterogeneity (Q = 25.26, P = 0.15, I²  =  24.78). Within-domain effects of primary dystonia were motor speed = -0.84, nonmotor speed = -0.83, global cognition = -0.65, language = -0.54, executive functioning = -0.53, learning/memory = -0.46, visuospatial/construction = -0.44, and simple/complex attention = -0.37 (P-values <0.01). High heterogeneity was observed in the motor/nonmotor speed and learning/memory domains. There was no evidence of publication bias. Moderator analyses were mostly negative but possibly underpowered. Blepharospasm samples showed worse performance than other focal/cervical dystonias. Those with inherited (ie, genetic) disease etiology demonstrated worse performance than acquired.

CONCLUSIONS

Dystonia patients consistently demonstrated lower performances on neuropsychological tests versus HCs. Effect sizes were generally moderate in strength, clustering around -0.50 SD units. Within the speed domain, results suggested cognitive slowing beyond effects from motor symptoms. Overall, findings indicate dystonia patients experience multidomain cognitive difficulties, as detected by neuropsychological tests. © 2022 International Parkinson and Movement Disorder Society.

Diagnostic Neurophysiologic Biomarkers for Task‐Specific Dystonia

Background

Task-specific dystonia (TSD) is a challenging clinical diagnosis with no objective diagnostic biomarkers.

Objective

The objective of this study was to test 2 neurophysiologic variables using transcranial magnetic stimulation as potential diagnostic biomarkers for TSD.

Methods

We tested (1) cortical silent period (CSP) and (2) dorsal inferior parietal lobule-motor cortex (dIPL-M1) physiologic connectivity in 9 patients with the writer's cramp form of TSD and 12 healthy volunteers on 2 separate sessions.

Results

CSP was significantly prolonged (P < 0.0001) in TSD and could classify TSD with high sensitivity and specificity with areas under the receiver operating characteristic curve (AUCs) = 0.94 and 0.90, respectively, for 2 separate sessions with an intraclass correlation = 0.79. dIPL-M1 interaction was notable for significant motor cortical inhibition in TSD compared with facilitation in healthy subjects (P < 0.0001) and could classify TSD with high sensitivity and specificity with AUCs = 0.96 and 0.86, respectively.

Conclusion

CSP and dIPL-M1 physiologic connectivity can classify TSD with high sensitivity, specificity, reproducibility, and reliability.

Effectiveness of Thalamic Ventralis Oralis Anterior and Posterior Nuclei Deep Brain Stimulation for Posttraumatic Dystonia

Herein we report that the ventralis oralis anterior and posterior (Voa/Vop) nuclei of the thalamus may be effective alternative targets for deep brain stimulation (DBS) to improve posttraumatic dystonia when the globus pallidus interna is traumatically damaged. This patient presented at age 35 years with a clinical diagnosis of posttraumatic cervical and bilateral upper limb acquired dystonia resulting from intracerebral and intraventricular hemorrhage after a motorcycle accident at age 19 years. Due to a right globus pallidus interna traumatic lesion, conventional DBS targeting of the inferior basal ganglia was not possible; thus, the alternative Voa/Vop nuclei target was implanted. The patient realized significant benefit and at last follow-up 3 years postoperatively continued to endorse marked benefit and improvement of dystonia symptoms with minimal adverse effects from bilateral DBS implantation in the alternative targets of the Voa/Vop nuclei of the thalamus.

Impaired Topographic Organization in Patients With Idiopathic Blepharospasm

Background: Idiopathic blepharospasm (BSP) is a common adult-onset focal dystonia. Neuroimaging technology can be used to visualize functional and microstructural changes of the whole brain. Method: We used resting-state functional MRI (rs-fMRI) and graph theoretical analysis to explore the functional connectome in patients with BSP. Altogether 20 patients with BSP and 20 age- and gender-matched healthy controls (HCs) were included in the study. Measures of network topology were calculated, such as small-world parameters (clustering coefficient [C _p], the shortest path length [L _p]), network efficiency parameters (global efficiency [E _glob], local efficiency [E _loc]), and the nodal parameter (nodal efficiency [E _nod]). In addition, the least absolute shrinkage and selection operator (LASSO) regression was adopted to determine the most critical imaging features, and the classification model using critical imaging features was constructed. Results: Compared with HCs, the BSP group showed significantly decreased E _loc. Imaging features of nodal centrality (E _nod) were entered into the LASSO method, and the classification model was constructed with nine imaging nodes. The area under the curve (AUC) was 0.995 (95% CI: 0.973-1.000), and the sensitivity and specificity were 95% and 100%, respectively. Specifically, four imaging nodes within the sensorimotor network (SMN), cerebellum, and default mode network (DMN) held the prominent information. Compared with HCs, the BSP group showed significantly increased E _nod in the postcentral region within the SMN, decreased E _nod in the precentral region within the SMN, increased E _nod in the medial cerebellum, and increased E _nod in the precuneus within the DMN. Conclusion: The network model in BSP showed reduced local connectivity. Baseline connectomic measures derived from rs-fMRI data may be capable of identifying patients with BSP, and regions from the SMN, cerebellum, and DMN may provide key insights into the underlying pathophysiology of BSP.

Brain oscillatory dysfunctions in dystonia

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

Association of Serum Uric Acid Levels in Meige's Syndrome

Uric acid (URIC) is a natural antioxidant, and it has been shown that low levels of URIC could be a risk factor for the development of Parkinson’s disease. Our aim was to investigate whether URIC also plays a role in Meige’s syndrome (MS). We conducted a cohort study to compare serum URIC levels between patients with MS and healthy controls. In addition, we analyzed the impact of URIC on the risk of MS and symptom severity. Compared with normal subjects, URIC content was remarkably decreased in MS patients. In addition, URIC was regarded as a protective factor for MS, as verified by multivariate logistic regression models. We also found non-linear relationships between the levels of serum URIC and the incidence rate of MS and the Burke-Fahn-Marsden dystonia rating scale score. Our study is the first to show a connection between serum URIC levels and MS. Low serum URIC levels indicate an increased risk of MS incidence and more severe clinical symptoms. Our findings provide new insights into the prevention and treatment of MS.

Next move in movement disorders (NEMO): developing a computer-aided classification tool for hyperkinetic movement disorders

INTRODUCTION

Our aim is to develop a novel approach to hyperkinetic movement disorder classification, that combines clinical information, electromyography, accelerometry and video in a computer-aided classification tool. We see this as the next step towards rapid and accurate phenotype classification, the cornerstone of both the diagnostic and treatment process.

METHODS AND ANALYSIS

The Next Move in Movement Disorders (NEMO) study is a cross-sectional study at Expertise Centre Movement Disorders Groningen, University Medical Centre Groningen. It comprises patients with single and mixed phenotype movement disorders. Single phenotype groups will first include dystonia, myoclonus and tremor, and then chorea, tics, ataxia and spasticity. Mixed phenotypes are myoclonus-dystonia, dystonic tremor, myoclonus ataxia and jerky/tremulous functional movement disorders. Groups will contain 20 patients, or 40 healthy participants. The gold standard for inclusion consists of interobserver agreement on the phenotype among three independent clinical experts. Electromyography, accelerometry and three-dimensional video data will be recorded during performance of a set of movement tasks, chosen by a team of specialists to elicit movement disorders. These data will serve as input for the machine learning algorithm. Labels for supervised learning are provided by the expert-based classification, allowing the algorithm to learn to predict what the output label should be when given new input data. Methods using manually engineered features based on existing clinical knowledge will be used, as well as deep learning methods which can detect relevant and possibly new features. Finally, we will employ visual analytics to visualise how the classification algorithm arrives at its decision.

ETHICS AND DISSEMINATION

Ethical approval has been obtained from the relevant local ethics committee. The NEMO study is designed to pioneer the application of machine learning of movement disorders. We expect to publish articles in multiple related fields of research and patients will be informed of important results via patient associations and press releases.

Second hit hypothesis in dystonia: Dysfunctional cross talk between neuroplasticity and environment?

One of the great mysteries in dystonia pathophysiology is the role of environmental factors in disease onset and development. Progress has been made in defining the genetic components of dystonic syndromes, still the mechanisms behind the discrepant relationship between dystonic genotype and phenotype remain largely unclear. Within this review, the preclinical and clinical evidence for environmental stressors as disease modifiers in dystonia pathogenesis are summarized and critically evaluated. The potential role of extragenetic factors is discussed in monogenic as well as adult-onset isolated dystonia. The available clinical evidence for a "second hit" is analyzed in light of the reduced penetrance of monogenic dystonic syndromes and put into context with evidence from animal and cellular models. The contradictory studies on adult-onset dystonia are discussed in detail and backed up by evidence from animal models. Taken together, there is clear evidence of a gene-environment interaction in dystonia, which should be considered in the continued quest to unravel dystonia pathophysiology.

Psychological Traits and Behavioural Influences in Patients with Dystonia-An Observational Cohort Study in a Romanian Neurology Department

(1) Background: Emerging evidence indicates that non-motor symptoms significantly influence the quality of life in dystonic patients. Therefore, it is essential to evaluate their psychological characteristics and personality traits. (2) Methods: Subjects with idiopathic dystonia and a matched control group were enrolled in this prospective observational cohort study. Inclusion criteria for patient group included idiopathic dystonia diagnosis, evolution exceeding 1 year, and signed informed consent. Inclusion criteria for the control group included lack of neurological comorbidities and signed informed consent. All subjects completed the DECAS Personality Inventory along with an additional form of demographic factors. Data (including descriptive statistics and univariate and multivariate analysis) were analyzed with SPSS. (3) Results: In total, 95 participants were included, of which 57 were in the patient group. Females prevailed (80%), and the mean age was 54.64 ± 12.8 years. The most frequent clinical features of dystonia were focal distribution (71.9%) and progressive disease course (94.73%). The patients underwent regular treatment with botulinum toxin (85.95%). In addition, patients with dystonia obtained significantly higher openness scores than controls, even after adjusting for possible confounders (p = 0.006). Personality traits were also different between the two groups, with patients more often being fantasists (p = 0.007), experimenters (p = 0.022), sophists (p = 0.040), seldom acceptors (p = 0.022), and pragmatics (p = 0.022) than control subjects. (4) Conclusion: Dystonic patients tend to have different personality profiles compared to control subjects, which should be taken into consideration by the treating neurologist.

Spread of segmental/multifocal idiopathic adult-onset dystonia to a third body site

BACKGROUND

Adult-onset focal dystonia can spread to involve one, or less frequently, two additional body regions. Spread of focal dystonia to a third body site is not fully characterized.

MATERIALS AND METHODS

We retrospectively analyzed data from the Italian Dystonia Registry, enrolling patients with segmental/multifocal dystonia involving at least two parts of the body or more. Survival analysis estimated the relationship between dystonia features and spread to a third body part.

RESULTS

We identified 340 patients with segmental/multifocal dystonia involving at least two body parts. Spread of dystonia to a third body site occurred in 42/241 patients (17.4%) with focal onset and 10/99 patients (10.1%) with segmental/multifocal dystonia at onset. The former had a greater tendency to spread than patients with segmental/multifocal dystonia at onset. Gender, years of schooling, comorbidity, family history of dystonia/tremor, age at dystonia onset, and disease duration could not predict spread to a third body site. Among patients with focal onset in different body parts (cranial, cervical, and upper limb regions), there was no association between site of focal dystonia onset and risk of spread to a third body site.

DISCUSSION AND CONCLUSION

Spread to a third body site occurs in a relative low percentage of patients with idiopathic adult-onset dystonia affecting two body parts. Regardless of the site of dystonia onset and of other demographic/clinical variables, focal onset seems to confer a greater risk of spread to a third body site in comparison to patients with segmental/multifocal dystonia at onset.

Prevalence and incidence of oromandibular dystonia: an oral and maxillofacial surgery service-based study

OBJECTIVES

Oromandibular dystonia is a focal dystonia characterized by sustained or intermittent contractions of the masticatory and/or tongue muscles. This epidemiological study aimed to estimate the prevalence and incidence of oromandibular dystonia in Kyoto (population: 1,465,701).

MATERIALS AND METHODS

The population sample was citizens of Kyoto who visited our department between 2015 and 2019 and were differentially diagnosed by an oromandibular dystonia specialist having idiopathic (primary) and acquired (secondary) oromandibular dystonia. A total of 144 patients (100 women and 44 men; mean age, 57.5 years) were analyzed for clinical features, and the prevalence (prevalence date, January 1, 2020) and annual incidence were estimated.

RESULTS

The male-to-female ratio was 1:2.3 (p<0.001). Age at onset was significantly (p<0.01) earlier in men (47.5 years) than that in women (56.9 years). The crude prevalence of oromandibular dystonia was estimated at 9.8 per 100,000 persons (95% confidence interval: 8.3-11.6) (idiopathic dystonia, 5.7 [4.6-7.1]; tardive dystonia, 3.4 [2.5-4.5]) and incidence at 2.0 (1.3-2.8) per 100,000 person-years (idiopathic dystonia, 1.2 [0.68-1.9], tardive dystonia, 0.68 [0.32-1.3]). The prevalence was 13.0 (10.5-15.8) in women and 6.3 (4.6-8.5) in men. All age groups showed female predominance. The highest prevalence was 23.6 (14.4-36.5) in women aged 60-69 years.

CONCLUSIONS

As this is an oral and maxillofacial surgery service-based study, the actual prevalence of oromandibular dystonia may be even higher.

CLINICAL RELEVANCE

It was suggested that oromandibular dystonia might be more common than cervical dystonia or blepharospasm.

Brain connectivity abnormalities and treatment-induced restorations in patients with cervical dystonia

BACKGROUND

The relationship between brain abnormalities and phenotypic characteristics in cervical dystonia (CD) patients has not been fully established, and little is known about the neuroplastic changes induced by botulinum toxin type A (BoNT-A) treatment.

METHODS

Ninety-two CD patients presenting with rotational torticollis and 45 healthy controls from our database were retrospectively screened. After clinical assessment, the 92 patients underwent baseline magnetic resonance imaging (MRI) followed by a single-dose injection of BoNT-A. Four weeks later, 76 out of the 92 patients were re-evaluated with the Tsui scale for dystonia severity, and 33 out of 76 patients completed post-treatment MRI scanning. Data-driven global brain connectivity and regional homogeneity in tandem with seed-based connectivity analyses were used to examine the functional abnormalities in CD and longitudinal circuit alterations that scaled with clinical response to BoNT-A. Multiple regression models were employed for the prediction analysis of treatment efficacy.

RESULTS

Cervical dystonia patients exhibited elevated baseline connectivity of the right postcentral gyrus with the left dorsomedial prefrontal cortex and right caudate nucleus, which was associated with their symptom severity. BoNT-A reduced excessive functional connectivity between the sensorimotor cortex and right superior frontal gyrus, which was significantly correlated with changes in Tsui score. Moreover, pre-treatment regional homogeneity of the left middle frontal gyrus was linearly related to varied response to treatment.

CONCLUSIONS

Our findings unravel dissociable connectivity of the sensorimotor cortex underlying the pathology of CD and central effects of BoNT-A therapy. Furthermore, baseline regional homogeneity with the left middle frontal gyrus may represent a potential evidence-based marker of patient stratification for BoNT-A therapy in CD.

Neuroimaging in idiopathic adult-onset focal dystonia

We aimed to study the attitude of Italian neurologists in the use of conventional MRI in patients with idiopathic adult-onset focal dystonia. Patients were included in the Italian Dystonia Registry by experts working in different Italian centers. MRI was available for 1045 of the 1471 (71%) patients included in the analysis. Using logistic regression analysis, we found that MRI was more likely to be performed in patients with cervical dystonia, spasmodic dysphonia, or non-task-specific upper limb dystonia, whereas it was less likely to be performed in patients with blepharospasm or task-specific upper limb dystonia. We did not find differences in the number of MRIs performed between neurological centers in Northern, Central, and Southern Italy. We conclude that although the diagnosis of idiopathic adult-onset dystonia is mainly based on clinical grounds, many movement disorder experts rely on MRI to confirm a diagnosis of idiopathic dystonia. We suggest that neuroimaging should be used in patients with adult-onset focal dystonia to rule out secondary forms.

Management of pregnancy and childbirth in a cervical dystonia patient with an implanted deep brain stimulation system: A case report

Deep brain stimulation (DBS) can lead to psychosocial and functional improvement in medically refractory cervical, segmental, or generalized moderate to severe dystonia. After treatment with DBS in women with dystonia, pregnancy can be planned. However, in the literature, there are no standardized clinical guidelines for the management of movement disorder treated with DBS during pregnancy. Herein, we report a 24-year-old female patient with cervical dystonia (CD) who have an implanted bilateral globus pallidus interna (GPi)-DBS. The patient got pregnant during the 5-year follow-up period after DBS surgery and then delivered a healthy baby via cesarean section under general anesthesia. A patient with CD who have a DBS system with a rechargeable battery could be managed safely during pregnancy and childbirth.

Descriptive epidemiological study on patients with movement disorders, with emphasis on Parkinson's disease

BACKGROUND

Knowing the epidemiological profile is relevant for improving healthcare practices. Movement disorders are neurological disorders characterized by the presence of involuntary movements. They have a negative impact on patients' quality of life.

OBJECTIVES

To outline the frequencies of the different diagnoses seen among patients, along with their demographic characteristics, at a hospital in São Paulo (SP), Brazil, and to highlight the clinical aspects of those with Parkinson's disease.

DESIGN AND SETTING

Retrospective descriptive epidemiological analysis at a specialized outpatient clinic in a state public hospital in São Paulo.

METHODS

Patients treated at this clinic over a four-year period were analyzed. Diagnoses, demographic variables and associations with clinical aspects of Parkinson's disease were evaluated.

RESULTS

Out of the 680 medical records analyzed, 58.4% related to females. Most patients were over 60 years of age, white, married and teachers. The most frequent diagnosis was Parkinson's disease, followed by essential tremor and dystonia. Parkinson's disease presented in the mixed clinical form; the most common initial symptom was tremor. The akinetic-rigid clinical form occurred in younger individuals and mostly presented with postural instability and freezing of gait in the early years of disease.

CONCLUSIONS

Parkinson's disease, essential tremor and dystonia were the most frequent diagnoses. Characteristics like sex, frequency of other pathological conditions and the clinical and demographic aspects of Parkinson's disease were consistent with the data in the relevant literature.

Sex differences in movement disorders

A number of studies reported the possible differences between men and women in movement disorders. Evidence shows that estrogens may have a neuroprotective effect and may modulate the neurodevelopment of the different brain structures. Movement disorders including Parkinson's disease, dementia with Lewy body, Huntington's disease, Tourette's syndrome, and dystonia among others display significant clinical differences between sexes, with structural differences in the dopaminergic pathways between men and women. Here we summarize the most relevant clinical aspects of some of the most common movement disorders, highlighting the differences in disease onset, clinical presentation, therapy, and outcomes. Increased recognition of these differences may help physicians better understand the pathophysiology of these conditions and provide a tailored therapeutic approach.

Treatment of Blepharospasm and Oromandibular Dystonia with Botulinum Toxins

Blepharospasm and oromandibular dystonia are focal dystonias characterized by involuntary and often patterned, repetitive muscle contractions. There is a long history of medical and surgical therapies, with the current first-line therapy, botulinum neurotoxin (BoNT), becoming standard of care in 1989. This comprehensive review utilized MEDLINE and PubMed and provides an overview of the history of these focal dystonias, BoNT, and the use of toxin to treat them. We present the levels of clinical evidence for each toxin for both, focal dystonias and offer guidance for muscle and site selection as well as dosing.

An examination of the neurocognitive profile and base rate of performance impairment in primary dystonia

BACKGROUND

Primary dystonia has been traditionally viewed as a motor disorder. However, non-motor symptoms are frequently present and significantly quality of life. Neuropsychiatric and cognitive symptoms have been identified, but prior studies have been limited in sample size and lack of control groups. This study examined the neurocognitive profile of a sample of persons with primary dystonia (PWD) as compared to demographically matched healthy control group.

METHODS

A cognitive test battery was administered to 25 PWD who presented for pre-surgical candidacy evaluation for deep brain stimulation surgery. The test battery domains included global cognitive function, attention, expressive language, visuospatial skills, memory, and executive functioning. Twenty-five age, gender, education-matched healthy control participants were compared to the PWD.

RESULTS

Compared to demographically matched healthy controls, PWD performed worse on measures of global cognitive function, attention, memory, and conceptualization. Based on normative comparison, a large portion of PWD were impaired on tasks of executive functioning and expressive language. Over 80% of the PWD showed impairment on at least one neurocognitive measure and over 60% showed impairment on 3 or more tests.

CONCLUSIONS

Neurocognitive deficits were prevalent among our PWD sample. These impairments were present across a broad range of cognitive domains. Given the degree of cognitive impairment found in this study, our results have implications for health care providers with providing interventions to PWD.

Sex differences in movement disorders

In a range of neurological conditions, including movement disorders, sex-related differences are emerging not only in brain anatomy and function, but also in pathogenesis, clinical features and response to treatment. In Parkinson disease (PD), for example, oestrogens can influence the severity of motor symptoms, whereas elevation of androgens can exacerbate tic disorders. Nevertheless, the real impact of sex differences in movement disorders remains under-recognized. In this article, we provide an up-to-date review of sex-related differences in PD and the most common hyperkinetic movement disorders, namely, essential tremor, dystonia, Huntington disease and other chorea syndromes, and Tourette syndrome and other chronic tic disorders. We highlight the most relevant clinical aspects of movement disorders that differ between men and women. Increased recognition of these differences and their impact on patient care could aid the development of tailored approaches to the management of movement disorders and enable the optimization of preclinical research and clinical studies.

Deep brain stimulation for cerebral palsy: where are we now?

Cerebral palsy (CP) is a complex disorder and children frequently have multiple impairments. Dystonia is a particularly frustrating impairment that interferes with rehabilitation and function and is difficult to treat. Of the available treatments, deep brain stimulation (DBS) has emerged as an option with the potential for large effect size in a subgroup of children. While brain stimulation has been used in CP for more than 40 years, modern devices and targeting methods are improving both the safety and efficacy of the procedure. Successful use of DBS depends on appropriate selection of patients, identification of effective neuroanatomical targets in each patient, careful neurosurgical procedure, and detailed follow-up evaluation and programming. The use of functional neurosurgery for neuromodulation in CP remains a technology in its infancy, but improving experience and knowledge are likely to make this one of the safest and most effective interventions for children with moderate-to-severe motor disorders. This review summarizes the current procedures for patient and target selection, and surgical implantation of DBS electrodes for CP. The history of DBS and future directions when used in secondary dystonia are also examined. WHAT THIS PAPER ADDS: Selection of candidates for deep brain stimulation (DBS) requires understanding of dystonia in cerebral palsy . DBS could become a first-line treatment option in some children.

Zolpidem for the Treatment of Dystonia

Background and Purpose: There are recent reports of zolpidem being effective for the treatment of a variety of movement disorders, due to its action on the gamma-aminobutyric acid A receptors in the thalamus, subthalamic nucleus, and globus pallidus, hence facilitating inhibitory pathways in the basal ganglia motor loop. Its beneficial effects have been described for Parkinson's disease and other related disorders. The objective of this study was to assess the therapeutic effects of zolpidem for various types of dystonia.

Methods: We conducted a literature search using MEDLINE via PubMed, Cochrane Library, EMBASE, Scopus, and Google Scholar.

Results: There were no randomized controlled trials. The literature included 6 case reports, 4 case series, and 1 non-randomized, non-controlled interventional trial. Overall, 49 adult participants (range 1–34 participants) with a mean age of 49.5 years were treated. Regardless of the dystonia subtype, a single dose of zolpidem at 10 mg causes improvement of symptoms for a mean duration of 3.4 h until patient returns to baseline. The main adverse effect noted was drowsiness, which was dose-dependent.

Conclusion: While the current available literature suggests that zolpidem may be an effective pharmacologic option for treating dystonia, however the quality of evidence remains limited. Larger sample size, methodological consistency, and randomized controlled trials with long-term patient follow-ups are necessary to come up with definitive conclusion.

Neuromodulation: Deep Brain Stimulation for Treatment of Dystonia

Dystonia is a heterogeneous, hyperkinetic movement disorder with sustained or intermittent abnormal postures, hyperkinetic muscle contractions, or repetitive movements. Classification of dystonia involves 2 axes: axis I and axis II, defining relevant clinical features and etiology, respectively. Medical therapy varies based on subtype and includes intramuscular botulinum toxin injections and oral anticholinergic pharmaceuticals. Deep brain stimulation became widely incorporated in 1999 after several landmark studies and has been effectively used in targets of the thalamus, pallidum, and subthalamic nucleus. New insights into pathophysiology of dystonia and genetic analysis continue to guide surgical technique toward ever-effective treatment.

Evaluation of stigmatization in hemifacial spasm and quality of life before and after botulinum toxin treatment

Hemifacial spasm (HFS) is a chronic disease that is characterized by involuntary tonic and clonic contractions of the muscles innervated by the ipsilateral facial nerve. Botulinum toxin (BTX) is the most effective medical treatment of this condition. The aim of our study was to evaluate stigma among patients diagnosed with HFS and to search quality of life and depression before and after BTX injection. Seven self-rating items (HFS-7) and seven questions related to stigmatization were administered to HFS patients. Participants also answered SF-36 health outcome measure and Beck depression inventory before and 4 weeks after the routine BTX injection. The severity of HFS was graded based on a five-point scale. Descriptive statistics and paired t test were applied. The level of significance was set at α = 0.05. Fourty HFS patients were prospectively included. Twenty-one (%52.5) were female and nineteen were male (47.5%) with a mean age of 57.1 (SD = 12.13; min-max = 27-78). 60% (n: 24) of patients were feeling themselves different from people without HFS. Beck depression inventory scores improved after BTX injection significantly (p < 0.05). All domains of SF-36 showed positive improvement after BTX injections. The improvement in general health perception, physical functioning, and vitality was statistically significant (p < 0.05). Although more than half of the patients felt themselves different from people without HFS, treatment of HFS with BTX significantly improved mental health and physical health, and depressive symptoms of the patients.

Lack of Association of the rs11655081 ARSG Gene with Blepharospasm

Blepharospasm (BSP) is a sub-phenotype of focal dystonia. A few genetic risk factors are considered to be implicated in the risk of developing BSP. There is recent evidence, based on results from GWAS and meta-analyses, to suggest that arylsulfatase G (ARSG), and more specifically rs11655081, is implicated in focal dystonia. The aim of the present study was to evaluate the effect of rs11655081 ARSG on BSP. A Greek cohort, which consisted of 206 BSP patients and an equal number of healthy controls, was genotyped for rs11655081. Only a marginal trend for the association between rs11655081 and the risk of BSP was found in the over-dominant model of inheritance [odds ratio, OR (95% confidence interval, CI): 0.64 (0.38-1.07), p = 0.088]. It is rather unlikely that rs11655081 across ARSG is a major genetic risk contributor for BSP.

Sensory Trick Frames: A New Device for Blepharospasm Patients

Objective

To determine whether the use of unique customized spectacles provided with modified side arms may be helpful in reducing benign essential blepharospasm (BEB) in patients describing periocular sensory tricks (ST).

Methods

A prospective descriptive study of patients with BEB with positive periocular or temporal region ST phenomenon response under the care of the Botox Clinic at Moorfields Eye Hospital, London, UK. Nine consecutive patients with BEB describing ST were recruited, and the disease frequency and severity were assessed with the Jankovic Rating Scale (JRS) and the Blepharospasm Disability Index (BSDI) before and after the use of the sensory trick frames (STF).

Results

A reduction in the score was noted in both severity (p = 0.0115) and frequency patterns (p = 0.0117) in the JRS in patients using the STF. A significant reduction of the BSDI score was also observed (p = 0.0314).

Conclusion

All the patients selected and fitted with the STF had a reduction in spasms and related symptoms. This new device may be helpful in some selected BEB patients who previously responded positively to periocular pressure alleviating maneuvers.

Epidemiology of benign essential blepharospasm: A nationwide population-based retrospective study in Taiwan

IMPORTANCE

This study provides a nationwide, population-based data on the incidence of benign essential blepharospasm in Asian adults.

BACKGROUND

To describe the incidence, patient demographics, and risk factors associated with benign essential blepharospasm.

DESIGN

Population-based retrospective study.

PARTICIPANTS AND SAMPLES

A total of 1325 patients with benign essential blepharospasm were identified.

METHODS

Patients with diagnosis of blepharopsasm between January 2000 and December 2013 were sampled using the Longitudinal Health Insurance Database 2000. Secondary blepharospasm that may be related to neurological, trauma, and ocular surface disease were excluded.

MAIN OUTCOME MEASURED

Multivariate conditional logistic regression was used to estimate the odds ratios for potential risk factors of benign essential blepharospasm.

RESULTS

The mean annual incidence was 0.10‰ (0.07‰ for males, and 0.12‰ for females). The peak incidence was in the 50 to 59-year-old age group (0.19‰). People living in urban regions have more risk of developing blepharospasm comparing to people living in less urban regions (p <0.01). White-collar workers also have higher chance of having blepharospasm (p<0.001). Significant difference between control group and case group in hyperlipidemia (p <0.001), sleep disorders (p <0.001), mental disorders (depression, anxiety, obsessive compulsive disorder) (p <0.001), dry eye-related diseases (dry eye, Sjögren's syndrome) (p <0.001), Parkinson's disease (p <0.004), and rosacea (p <0.021) were also identified.

CONCLUSIONS AND RELEVANCE

Higher level of urbanization, white-collar work, sleep disorders, mental health diseases, dry eye-related diseases, Parkinsonism, and rosacea are possible risk factors for benign essential blepharospasm.

Reduced Frequency of Ipsilateral Express Saccades in Cervical Dystonia: Probing the Nigro-Tectal Pathway

Background

Cervical dystonia is a hyperkinetic movement disorder of unknown cause. Symptoms of cervical dystonia have been induced in animals in which the integrity of the nigro-tectal pathway is disrupted, resulting in reduced inhibition of the deep layers of the superior colliculus. This same pathway is believed to play a critical role in saccade generation, particularly visually guided, express saccades. It was hypothesized that individuals with cervical dystonia would present with a higher frequency of express saccades and more directional errors.

Methods

Eight individuals with cervical dystonia and 11 age- and sex-matched control participants performed three saccadic paradigms: pro-saccade, gap, and anti-saccade (120 trials per task). Eye movements were recorded using electro-oculography.

Results

Mean saccadic reaction times were slower in the cervical dystonia group (only statistically significant in the anti-saccade task, F(1, 35)  =  4.76, p  =  0.036); participants with cervical dystonia produced fewer directional errors (mean 14% vs. 22%) in the anti-saccade task; and had similar frequencies of express saccades in the gap task relative to our control population (chi-square  =  1.13, p  =  0.287). All cervical dystonia participants had lower frequencies of express saccades ipsilateral to their dystonic side (the side to which their head turns), (chi-square  =  3.57, p  =  0.059).

Discussion

The finding of slower saccadic reaction times in cervical dystonia does not support the concept of reduced inhibition in the nigro-tectal pathway. Further research is required to confirm the observed relationship between the lateralization of lower frequencies of express saccades and direction of head rotation in cervical dystonia.

Deep Brain Stimulation Versus Peripheral Denervation for Cervical Dystonia: A Systematic Review and Meta-Analysis

BACKGROUND

Cervical dystonia is a disabling medical condition that drastically decreases quality of life. Surgical treatment consists of peripheral nerve denervation procedures with or without myectomies or deep brain stimulation (DBS). The current objective was to compare the efficacy of peripheral denervation versus DBS in improving the severity of cervical dystonia through a systematic review and meta-analysis.

METHODS

A search of PubMed, MEDLINE, EMBASE, and Web of Science electronic databases was conducted in accordance with PRISMA guidelines. Preoperative and postoperative Toronto Western Spasmodic Torticollis Rating Scale (TWSTRS) total scores were used to generate standardized mean differences and 95% confidence intervals (CIs), which were combined in a random-effects model. Both mean percentage and absolute reduction in TWSTRS scores were calculated. Absolute reduction was used for forest plots.

RESULTS

Eighteen studies met the inclusion criteria, comprising 870 patients with 180 (21%) undergoing DBS and 690 (79%) undergoing peripheral denervation procedures. The mean follow-up time was 31.5 months (range, 12-38 months). In assessing the efficacy of each intervention, forest plots revealed significant absolute reduction in total postoperative TWSTRS scores for both peripheral denervation (standardized mean difference 1.54; 95% CI 1.42-1.66) and DBS (standardized mean difference 2.07; 95% CI 1.43-2.71). On subgroup analysis, DBS therapy was significantly associated with improvement in postoperative TWSTRS severity (standardized mean difference 2.08; 95% CI 1.66-2.50) and disability (standardized mean difference 2.12; 95% CI 1.57-2.68) but not pain (standardized mean difference 1.18; 95% CI 0.80-1.55).

CONCLUSIONS

Both peripheral denervation and DBS are associated with a significant reduction in absolute TWSTRS total score, with no significant difference in the magnitude of reduction observed between the 2 treatments. Further comparative data are needed to better evaluate the long-term results of both interventions.

Effects of Repeated Eyelid Injections with Botulinum Toxin A on Innervation of Treated Muscles in Patients with Blepharospasm

PURPOSE

To assess changes in innervation and muscle morphology after repeated botulinum toxin A injections in subjects with benign essential blepharospasm.

METHODS

Surgical waste specimens were processed for histologic examination of nerve fibers, neuromuscular junctions, fiber size, and central nucleation and compared to age matched controls and to two subjects with blepharospasm that had not received botulinum toxin A injections.

RESULTS

There was a significant increase in amount of nerve fibers and numbers of neuromuscular junctions in the orbicularis oculi muscles from subjects with blepharospasm treated repetitively with botulinum toxin A. In addition there was a significant decrease in mean muscle fiber cross-sectional area and an increase in central nucleation. The specimens from the subjects with only blepharospasm had the same density of nerves but had intermediate levels of neuromuscular junctions.

CONCLUSIONS

These data suggest that repeated injections of botulinum toxin A has an effect on nerve and neuromuscular junction numbers, which are partly mirrored in orbicularis oculi muscle from subjects with blepharospasm only. These studies suggest the potential for modulating these changes in order to extend the duration of effectiveness of botulinum toxin.

Possible Post-Traumatic Focal Dystonia Associated with Tau Pathology Localized to Putamen-Globus Pallidus

Background

Dystonia is often associated with damage to basal ganglia (BG), but neuropathological assessments of these cases are infrequent.

Methods

A brain was assessed with possible post-traumatic focal dystonia that appeared after an accident occurred during childhood.

Results

Tau pathology was found within putamen and globus pallidus of the right hemisphere, and chronic traumatic encephalopathy (CTE) was observed in the cortex of the left hemisphere. No diffuse axonal injury (DAI), β-amyloid, ubiquitin, p62, or pTDP43 pathology was found.

Conclusions

Post-traumatic dystonia could be associated with post-traumatic tau pathology formation. However, more cases are necessary to establish causality. The tau lesions found in the BG of this patient did not fit within CTE criteria. We hypothesize that due to the anatomo-histological characteristics of the BG, tau pathology associated with brain traumas produce histopathological patterns different from sulcal-tau pathology, which is the only tau pathology distribution currently accepted as pathognomonic of CTE.