The non-motor syndrome of primary dystonia: clinical and pathophysiological implications

Comparison of different surgical strategies for cervical dystonia: Evidence from Bayesian network analysis

BACKGROUND AND PURPOSE

Several surgical techniques have been used to treat cervical dystonia (CD), however, to date, the optimal surgical technique for CD remains controversial. We therefore conducted the first network meta-analysis to compare different surgical strategies for CD to inform clinical practice.

METHODS

Electronic databases were searched for surgical strategies for treating CD. The primary outcome was improvement in total Toronto Western Spasmodic Torticollis Rating Scale (TWSTRS) score. Subgroup analysis was performed to compare short-term (< 1 year) and long-term (≥ 1 year) outcomes. Safety outcomes included surgery-related adverse events (AEs).

RESULTS

A total of 55 trials with 2032 patients employing five surgical strategies were identified, including globus pallidus internus (GPi)/subthalamic nucleus (STN)-deep brain stimulation (DBS), selective peripheral denervation (SPD), microvascular decompression (MVD) and pallidotomy. All strategies led to significant improvement in total TWSTRS score (mean improvement range 18.65-28.22). GPi-DBS showed significantly greater enhancement than SPD for the whole dataset (mean difference [MD] 7.03, 95% credible interval [Crl] 1.53-12.56), while both GPi-DBS (MD 8.05, 95% Crl 2.35-13.80) and STN-DBS (MD 10.71, 95% Crl 2.22-19.20) exhibited more long-term improvement than SPD. Regarding safety outcomes, GPi/STN-DBS and MVD were associated with fewer surgery-related AEs than SPD (ln odds ratio range -1.68 to -1.41).

CONCLUSION

We conclude that DBS should be the preferred surgical option for CD, and the STN is a promising alternative target choice due to its comparable efficacy with the GPi. However, more direct evidence is still required.

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

BACKGROUND AND OBJECTIVES

The aim of this study was to explore the impacts of subthalamic nucleus deep brain stimulation (STN-DBS) on both motor and nonmotor symptoms in individuals with Meige syndrome, as well as further investigates prognostic factors for long-term postoperative outcomes.

METHODS

We retrospectively reviewed a consecutive cohort of patients with intractable Meige syndrome who underwent STN-DBS at our center from January 2016 to July 2023. Motor function, quality of life, neuropsychological status, and mood state were evaluated with standardized scales at baseline and every 3 to 6 months thereafter. Univariate and multivariate linear regression analyses were used to determine independent risk factors that affect long-term motor function after STN-DBS.

RESULTS

Fifty-five patients were ultimately analyzed with a mean follow-up of 62.1 ± 25.7 months. At the final postoperative assessment, movement and disability scores of the Burke-Fahn-Marsden Dystonia Rating Scale demonstrated improvements of 61% (P < .001) and 57% (P < .001), respectively. Postoperative scores on the 36-item Short-Form General Health Survey showed significant improvement from baseline. Global cognitive function and neuropsychological status remained stable during continuous neurostimulation. Multivariate linear regression analysis revealed that longer disease duration (standardized β coefficient = -0.294, 95% CI -0.039 to -0.007, P = .006), older age at surgery (standardized β coefficient = -0.382, 95% CI -0.014 to -0.004, P = .001), and smaller volume of tissue activated within the sensorimotor subregion of STN (standardized β coefficient = 0.309, 95% CI 0.001-0.004, P = .004) were independently correlated with poorer long-term motor performance.

CONCLUSION

Bilateral STN-DBS is an effective, safe, and promising treatment option for Meige syndrome, which can improve motor function and quality of life without cognitive and mood side effects. Early diagnosis, prompt intervention, and accurate lead placement in the dorsolateral STN are crucial to optimize long-term therapeutic outcomes.

Navigating the social world with neck dystonia: An interpretative phenomenological analysis

Neck dystonia is a neurological condition, characterised by involuntary movements of the neck muscles, causing twisted head positions and often pain and head tremor. Ten participants with neck dystonia were interviewed and the data was analysed using an interpretative phenomenological analysis approach. Three themes were constructed: (1) dismissed by others for having an unfamiliar condition; (2) negotiating a new social identity; and (3) managing the stigma of a visible condition. It is proposed that psychological support could benefit people with neck dystonia who experience difficulties arising from identity management and stigma. Systemic interventions, such as education campaigns, are also proposed to help address stigmatising attitudes.

Vibro-tactile stimulation of the neck reduces pain in people with cervical dystonia: a proof-of-concept study

BACKGROUND

Pain is a common non-motor symptom in patients with cervical dystonia (CD), severely impacting their quality of life. The pathophysiology of CD is incompletely understood but it involves altered processing of proprioceptive and pain signals.

OBJECTIVES

The purpose of this proof-of-concept study was to determine if vibro-tactile stimulation (VTS)-a non-invasive form of neuromodulation targeting the somatosensory system-can modulate neck pain in people with CD.

METHODS

In a multi-center study, 44 CD patients received VTS to sternocleidomastoid and/or trapezius muscles for up to 45 min under 9 different stimulation conditions that either targeted a single or a pair of muscles. The primary outcome measure was a perceived pain score (PPS) rated by participants on a 100-point analogue scale.

RESULTS

During VTS, 29/44 (66%) of participants experienced a reduction in PPS of at least 10% with 17/44 (39%) reporting a reduction in pain of 50% or higher. After VTS cessation, 57% of participants still reported a 10% or higher reduction in PPS. Effects were significant at the group level and persisted for up to 20 min post-treatment. No distinct optimal stimulation profiles were identified for specific CD phenotypes. Clinical markers of disease severity or duration did not predict the degree of VTS-induced pain reduction.

CONCLUSION

This proof-of-concept study demonstrates the potential of VTS as a new non-invasive therapeutic option for treating neck pain associated with CD. Further research needs to delineate optimal dosage and long-term effects.

Memory-Guided Saccades and Non-Motor Symptoms Improve after Botulinum Toxin Therapy in Cervical Dystonia

Background/Objectives: Cervical dystonia (CD) is a condition characterized by involuntary activity of cervical muscles, which is often accompanied by various non-motor symptoms. Recent studies indicate impaired saccadic eye movements in CD. Local administration of botulinum toxin type A (BoNT/A), which causes temporary paralysis of the injected muscle, is the first-line treatment of focal dystonia, including CD. To our knowledge, concurrent observation of the effect of BoNT/A on smooth eye movements, voluntary saccades, memory-guided saccades, and antisaccades in CD has not yet been explored. The aim of this study was to assess the effect of BoNT/A on eye movements and non-motor symptoms in patients with CD, which, when altered, could imply a central effect of BoNT/A. Methods: Thirty patients with CD performed smooth pursuit, prosaccadic expression, memory-guided saccades, and antisaccade tasks; eye movements were recorded by an eye tracker. Motor and non-motor symptoms, including depression, anxiety, pain, disability, and cognitive changes prior to and after BoNT/A administration, were also evaluated. Results: The number of correct onward counts (p < 0.001), overall correct memory-guided saccades count (p = 0.005), motor symptoms (p = 0.001), and non-motor symptoms, i.e., anxiety (p = 0.04), depression (p = 0.02), and cognition (p < 0.001) markedly improved after BoNT/A administration. Conclusions: Memory-guided saccades, depression, and anxiety improve after BoNT/A in CD.

Current use of neurotoxins for alleviating symptoms of cervical dystonia

INTRODUCTION

Cervical dystonia (CD) causes involuntary movements and postures of the head, neck, and shoulders, as well as nonmotor symptoms including pain, mood, and sleep dysfunction, and impacts quality of life. The first-line treatment for CD is botulinum neurotoxin (BoNT) injections.

AREAS COVERED

The clinical presentation and diagnosis of CD, as well as where BoNT resides in the treatment landscape, is reviewed first. Next, the mechanism of action and the pharmacological differences in the available preparations of BoNT products are explained. The evidence base for motor and nonmotor efficacy and safety of the available BoNT formulations is reviewed, with attention to duration of benefit as a driver of patient satisfaction. Practical determinants of BoNT efficacy are reviewed including muscle selection, accurate muscle injection, factors related to poor or deteriorating response, and immunogenicity.

EXPERT OPINION

BoNT represents a significant advancement in the treatment of CD. More accurate diagnosis, muscle selection and targeting, and dosing can improve outcomes with existing BoNT formulations. Further refinement of BoNT potency, duration of action, safety, and immunogenicity will help reduce unmet needs in the magnitude and duration of benefit. Additional validation of DBS and MRI-guided focused ultrasound may expand options for patients with toxin nonresponse.

Moving on with (social) cognition in idiopathic cervical dystonia

OBJECTIVE

Cervical dystonia (CD) is a movement disorder characterized by involuntary muscle contractions causing sustained twisting movements and abnormal postures of the neck and head. Assumed affected neuronal regions are the cortico-striatal-thalamo-cortical circuits, which are also involved in cognitive functioning. Indeed, impairments in different cognitive domains have been found in CD patients. However, to date studies have only investigated a limited range of cognitive functions within the same sample. In particular, social cognition (SC) is often missing from study designs. Hence, we aimed to evaluate a broad range of cognitive functions including SC in CD patients.

METHOD

In the present study 20 idiopathic CD patients and 40 age-, gender-, and IQ-matched healthy controls (HCs) were assessed with tests for non-SC (verbal memory, psychomotor speed, and executive functions) as well as for SC (emotion recognition, Theory of Mind (ToM), and empathy).

RESULTS

CD patients scored on average significantly lower than HC on tests for non-SC, but did not show impairments on any of the tests for SC.

CONCLUSIONS

The current study showed impairments in non-SC in CD, but intact social cognitive functions. These results underline the importance of recognizing non-motor symptoms in idiopathic CD patients, but emphasize a focus on identifying strengths and weaknesses in cognitive functioning as these influence daily life activities.

Application of sensory nerve quantitative tests to analyze the subtypes of motor disorders in Parkinson's disease

This study investigated the sensory nerve function in people with different subtypes of Parkinson's disease (PD), which included the tremor-dominant (TD) group (n = 30), postural instability and gait disorder (PIGD) group (n = 33), and healthy-controls (HC) group (n = 33). Sural nerve's current perception threshold (CPT) and pain tolerance threshold (PTT) in both feet were measured at different frequencies. Results were evaluated using the mini-mental state examination (MMSE), Hoehn Yahr scale (H-Y) , and 3-meter timed-up-and-go-test (TUGT). The MMSE scores of the TD and HC groups were higher than those of the PIGD group (TD < HC). The 3-meter TUGT scores of the PIGD group were higher than theTD and HC groups (TD > HC). The PIGD patients experienced a significantly shorter disease duration and higher H-Y score than the TD patients ( P  < 0.05). The values of 2 KHz CPT of left-side (CPTL), 2KHz CPT of right-side (CPTR), and 5 Hz CPTR in the PIGD group were significantly higher compared to the TD and HC groups ( P  < 0.05, Bonferroni correction). Additionally, the values of 250 Hz CPTL, 5 Hz CPTL, 250 Hz CPTR, 2 kHz PTT of left-side (PTTL), 250 Hz PTTL, and 5 Hz PTTL in the PIGD group were significantly elevated relative to the TD group ( P  < 0.05, Bonferroni correction). Distinctive current threshold perception and PTT of the sural nerve can be observed in patients with varying PD subtypes, and sensory nerve conduction threshold electrical diagnostic testing can detect these discrepancies in sensory nerve function.

Are Cognitive Symptoms Part of the Phenotypic Spectrum of Idiopathic Adult-Onset Dystonia? Summary of Evidence from Controlled Studies

BACKGROUND

Cognitive dysfunction has been reported in idiopathic adult-onset dystonia (IAOD), but whether this is a primary or secondary component of the disorder remains uncertain.

OBJECTIVE

Here, we aimed to analyze the key domains of abnormal cognitive performance in IAOD and whether this is associated with motor or mood changes.

METHODS

Article selection for our critical review was guided by PRISMA guidelines (mesh terms "dystonia" and "cognitive," publication period: 2000-2022). Only peer-reviewed, English-language original case-control studies involving patients with IAOD who were not exposed to dopamine- or acetylcholine-modulating agents and validated cognitive assessments were included.

RESULTS

Abstract screening ultimately yielded 22 articles for full-text review and data extraction. A greater proportion of studies (17 of 22, 82%) reported abnormal cognitive performance in IAOD. Most of these studies focused on blepharospasm (BSP) and cervical dystonia (10 and 14, respectively). Most studies reporting cognitive impairment (11 of 17) identified multidomain impairment in cognition. Executive functions were the domain most frequently explored (14 of 22 studies), 79% of which detected worse performance in people with dystonia. Results related to other domains were inconclusive. Cognitive abnormalities were independent of motor symptoms in most studies (7 of 12) that explored this relationship and independent of mood status in all 8 that investigated this.

CONCLUSIONS

Within IAOD, cognitive dysfunction (in particular, executive dysfunction) has been documented mainly in BSP and cervical dystonia. More comprehensive testing is warranted to assess abnormalities in other domains and in other forms of IAOD, as well as to evaluate longitudinal progression of cognitive disturbances in this condition.

Impact of Physiotherapy in the Treatment of Pain in Cervical Dystonia

Background

Cervical dystonia (CD) is the most common form of focal dystonia in adults. Studies show that physiotherapy (PT) in combination with BoNT has an effect on pain in cervical dystonia. We intended to test this hypothesis in a real-world setting to answer the question of whether pain is a good target symptom for prescribing PT. We also aimed to assess which form of PT is most appropriate for the treatment of pain.

Methods

Study design: cross-sectional survey-based study of 91 patients with a confirmed diagnosis of cervical dystonia. The survey consisted of a questionnaire on type, frequency and content of physiotherapy, an assessment of quality of life with the Craniocervical Dystonia Questionnaire 24 (CDQ 24) and subjective pain scores.

Results

53.8% of patients received physiotherapy, mostly a mixture of exercises to either correct the abnormal posture or to reduce the muscle tone. Additional therapies included stress-reducing exercises (14.3%), psychotherapy (9.9%) and EMG biofeedback (2.2%). Patients who received PT showed a non-significant tendency towards higher pain scores. The severity of dystonia-associated pain was significantly associated with the patients' quality of life (F (1,54) = 22.9, adjusted R2 = 0.286, p < 0.001).

Discussion

Pain is a frequent problem in patients with CD and severely affects quality of life. Physiotherapy could therefore be a valuable treatment option for patients with CD and pain.

Highlights

Our uncontrolled study illustrates the high frequency of physiotherapy in addition to BoNT treatment in a real-life cohort of patients with cervical dystonia. We were able to show that PT reduces patients' perceived pain in a patient reported outcome measure. This highlights the importance of PT in reducing CD-related pain, which considerably impairs quality of life.

The use of sertraline to treat an adolescent of dystonia comorbid with major depressive disorder with psychotic features

Dystonia is characterized by sustained or intermittent involuntary muscle contractions. Psychiatric symptoms are essential non-motor features of dystonia, and higher risks of depressive and anxiety disorders have been reported. The precedence of psychiatric to motor symptoms in some patients and the dopaminergic and serotonergic system involvement in both the motor and psychiatric aspects suggest these psychiatric disorders may be intrinsic to the neurobiology of dystonia. Nevertheless, psychiatric comorbidities are often construed as secondary reactions to motor disabilities and the negative bio-psycho-social impacts of dystonia, leading to underdiagnosis and undertreatment. Research on antidepressant use in dystonia is scarce, especially in children and adolescents. This report presents a 17-year-old female with dystonia comorbid with depression with psychotic features, whose motor symptoms improved but psychiatric symptoms persisted with dopaminergic pharmacotherapy. Sertraline was finally added 5 years after the onset and successfully managed her psychotic depression without worsening motor symptoms. Early detection, prompt diagnosis, and timely holistic treatment with dopaminergic agents, antidepressants, and psychosocial interventions are critical for the mental health of dystonia patients.

A Systematic Review of Cognition in Cervical Dystonia

Growing evidence points to a spectrum of non-motor symptoms, including cognitive difficulties that have a greater impact on functional outcomes and quality of life than motor symptoms in cervical dystonia (CD). Some cognitive impairments have been reported; however, findings are inconsistent, and described across mixed groups of dystonia. The current review aimed to examine the evidence for cognitive impairments in CD. MEDLINE, EMBASE, PsychINFO and Web of Science databases were searched. Studies were included if they met the following criteria (i) cross-sectional or longitudinal studies of adults with CD, (ii) where the results of standardised measures of cognitive or neuropsychological function in any form were assessed and reported, (iii) results compared to a control group or normative data, and (iv) were published in English. Results are presented in a narrative synthesis. Twenty studies were included. Subtle difficulties with general intellectual functioning, processing speed, verbal memory, visual memory, visuospatial function, executive function, and social cognition were identified while language, and attention and working memory appear to be relatively spared. Several methodological limitations were identified that should be considered when interpreting the evidence to describe a specific profile of cognitive impairment in CD. Clinical and research implications are discussed.

Idiopathic cervical dystonia and non-motor symptoms: a pilot case-control study on autonomic nervous system

PURPOSE

Non-motor symptoms, such as sleep disturbances, fatigue, neuropsychiatric manifestations, cognitive impairment, and sensory abnormalities, have been widely reported in patients with idiopathic cervical dystonia (ICD). This study aimed to clarify the autonomic nervous system (ANS) involvement in ICD patients, which is still unclear in the literature.

METHODS

We conducted a pilot case-control study to investigate ANS in twenty ICD patients and twenty age-sex-matched controls. The Composite Autonomic System Scale 31 was used for ANS clinical assessment. The laser Doppler flowmetry quantitative spectral analysis, applied to the skin and recorded from indices, was used to measure at rest, after a parasympathetic activation (six deep breathing) and two sympathetic stimuli (isometric handgrip and mental calculation), the power of high-frequency and low-frequency oscillations, and the low-frequency/high-frequency ratio.

RESULTS

ICD patients manifested higher clinical dysautonomic symptoms than controls (p < 0.05). At rest, a lower high-frequency power band was detected among ICD patients than controls, reaching a statistically significant difference in the age group of ≥ 57-year-olds (p < 0.05). In the latter age group, ICD patients showed a lower low-frequency/high-frequency ratio than controls at rest (p < 0.05) and after mental calculation (p < 0.05). Regardless of age, during handgrip, ICD patients showed (i) lower low-frequency/high-frequency ratio (p < 0.05), (ii) similar increase of the low-frequency oscillatory component compared to controls, and (iii) stable high-frequency oscillatory component, which conversely decreased in controls. No differences between the two groups were detected during deep breathing.

CONCLUSION

ICD patients showed ANS dysfunction at clinical and neurophysiological levels, reflecting an abnormal parasympathetic-sympathetic interaction likely related to abnormal neck posture and neurotransmitter alterations.

Function and dysfunction of the dystonia network: an exploration of neural circuits that underlie the acquired and isolated dystonias

Dystonia is a highly prevalent movement disorder that can manifest at any time across the lifespan. An increasing number of investigations have tied this disorder to dysfunction of a broad "dystonia network" encompassing the cerebellum, thalamus, basal ganglia, and cortex. However, pinpointing how dysfunction of the various anatomic components of the network produces the wide variety of dystonia presentations across etiologies remains a difficult problem. In this review, a discussion of functional network findings in non-mendelian etiologies of dystonia is undertaken. Initially acquired etiologies of dystonia and how lesion location leads to alterations in network function are explored, first through an examination of cerebral palsy, in which early brain injury may lead to dystonic/dyskinetic forms of the movement disorder. The discussion of acquired etiologies then continues with an evaluation of the literature covering dystonia resulting from focal lesions followed by the isolated focal dystonias, both idiopathic and task dependent. Next, how the dystonia network responds to therapeutic interventions, from the "geste antagoniste" or "sensory trick" to botulinum toxin and deep brain stimulation, is covered with an eye towards finding similarities in network responses with effective treatment. Finally, an examination of how focal network disruptions in mouse models has informed our understanding of the circuits involved in dystonia is provided. Together, this article aims to offer a synthesis of the literature examining dystonia from the perspective of brain networks and it provides grounding for the perspective of dystonia as disorder of network function.

Unraveling the Twist: Spatial Navigational Challenges in Cervical Dystonia

BACKGROUND

Cervical dystonia (CD) is an intricate neurological condition with motor and nonmotor symptoms. These include disruptions in visual perception, self-orientation, visual working memory, and vestibular functions. However, the specific impact of CD on perceiving self-motion direction, especially with isolated visual or vestibular stimuli, remains largely unexplored.

OBJECTIVE

This study aimed to examine the effects of CD on linear motion perception, hypothesizing impaired heading discrimination in both vestibular and visual tasks, and that such deficits correlate with the disease severity.

METHODS

We employed a cutting-edge motion platform to precisely control whole-body linear motion. Through repeated two-alternative forced-choice tasks, we assessed vestibular heading direction discrimination. Participants observed dynamic star clouds in immersive virtual reality and indicated their perceived self-motion direction, evaluating visual heading direction discrimination. Sensitivity to direction variations and response accuracy errors were analyzed using robust Gaussian cumulative distribution psychometric functions.

RESULTS

Heading perception is impaired in individuals with CD, particularly evident in vestibular heading discrimination. CD severity correlated with elevated thresholds for both vestibular and visual heading discrimination. Surprisingly, lateralized CD did not introduce bias in either system, suggesting widespread disruption over localized effects.

CONCLUSIONS

Contrary to previous beliefs, our findings challenge the idea that CD-related heading discrimination issues mainly arise from peripheral vestibular effects. Instead, abnormal proprioceptive input from dystonic neck muscles introduces noise into the central mechanism integrating visual, vestibular, and proprioceptive signals. These insights into spatial navigation deficits have implications for future CD research. © 2023 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society. This article has been contributed to by U.S. Government employees and their work is in the public domain in the USA.

A comprehensive cognitive analysis of cervical dystonia: A single centre study

Introduction

Cervical dystonia (CD) presents as a motor disorder but has a number of non-motor features. Studies have demonstrated diverse changes in cognition in patients with CD. The rarity of this disorder, phenotypic heterogeneity, and, in particular, a lack of consistency in cognitive testing measures limits clear definition of cognitive changes in this disorder. The relationship between cognition, motor symptoms and quality of life has not been well defined. We undertook a comprehensive analysis of cognition in CD.

Methods

Patients with adult onset idiopathic isolated CD (AOICD) who had completed a battery of cognitive assessments- general intellectual functioning, verbal and visual memory, executive functions and social cognition measures, were included. Participants were assessed for mood symptoms, motor severity and quality of life.

Results

13 patients (8 women) with AOICD were included covering 40 cognitive subtests. Mean age was 59.9 years and mean TWSTRS-2 severity was 11. Mean estimated premorbid function was in the normal range. Overall performance on most measures were within normal limits. The lowest mean z-score was observed in Florida Affect Battery (social cognition) subtests, z = -1.75 and -0.81. and in verbal recall, z = -0.82. The majority of patients (75%) scored below population mean on spatial working memory and (62%) performed below population mean on word retrieval and working memory.

Conclusion

We provide detailed cognitive results across a wide range of measures. Although patients tended towards average outcomes on the majority of tests, poorer performance than expected averages were noted in measures of social cognition, word retrieval, spatial working memory and, processing speed.

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

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

Social cognition deficits are associated with lower quality of life in cervical dystonia: A single centre study

Background and objectives

Patients with cervical dystonia (CD) demonstrate significant non-motor symptoms including sensory, psychiatric and cognitive features. It has been shown that the non-motor symptoms have a major influence on quality of life. Social cognition, particularly deficits in Theory of Mind (ToM), can affect the development of interpersonal relationships, understanding of social situations and can affect patient outcomes.We used the "Faux Pas" measure of social cognition to assess ToM in patients with CD and compared this with quality of life, disease severity and psychiatric symptoms.

Methods

Patients with adult-onset idiopathic isolated cervical dystonia were assessed using the "Faux Pas" questionnaire. Validated questionnaires were used to assess mood symptoms (BAI/BDI and HADS) and quality of life (CDIP-58). Disease-specific disability, motor severity and psychosocial symptoms were measured using TWSTRS2. Faux pas results were compared with published healthy control values.

Results

32 participants (19 female) were included with a mean age of 57.7 years. 20 participants met criteria for excess mood symptoms (anxiety and/or depression). Mean CDIP-58 was 31.9. There was no relationship between faux pas outcomes and motor severity. However, correlation analyses showed that participants who performed worse on the faux pas questionnaire had lower quality of life.

Conclusion

The non-motor symptoms, including social cognition, are often neglected. We have demonstrated that low quality of life in CD is associated with to abnormal social cognition. Clinicians should be mindful of these symptoms, particularly in patients reporting low treatment satisfaction.

Isolated Cervical Dystonia: Diagnosis and Classification

This document presents a consensus on the diagnosis and classification of isolated cervical dystonia (iCD) with a review of proposed terminology. The International Parkinson and Movement Disorder Society Dystonia Study Group convened a panel of experts to review the main clinical and diagnostic issues related to iCD and to arrive at a consensus on diagnostic criteria and classification. These criteria are intended for use in clinical research, but also may be used to guide clinical practice. The benchmark is expert clinical observation and evaluation. The criteria aim to systematize the use of terminology as well as the diagnostic process, to make it reproducible across centers and applicable by expert and non-expert clinicians. Although motor abnormalities remain central, increasing recognition has been given to nonmotor manifestations, which are incorporated into the current criteria. Three iCD presentations are described in some detail: idiopathic (focal or segmental) iCD, genetic iCD, and acquired iCD. The relationship between iCD and isolated head tremor is also reviewed. Recognition of idiopathic iCD has two levels of certainty, definite or probable, supported by specific diagnostic criteria. Although a probable diagnosis is appropriate for clinical practice, a higher diagnostic level may be required for specific research studies. The consensus retains elements proven valuable in previous criteria and omits aspects that are no longer justified, thereby encapsulating diagnosis according to current knowledge. As understanding of iCD expands, these criteria will need continuous revision to accommodate new advances. © 2023 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.

The Impact of Non-Motor Symptoms on Quality of Life in Cervical Dystonia

Cervical dystonia (CD) is characterized by cranial muscle overactivity leading to abnormal intermittent or continuous posturing of the head. Nowadays, the treatment of patients suffering from this condition focuses principally on the motor component of the disorder, certainly the invaliding part; however, it leaves out the non-motor one that has a similarly invalidated effect on the quality of the subject's life. This review was conducted on studies investigating the impact of non-motor symptoms on levels of quality of life. We searched on the PubMed, EMBASE and Web of Science databases and screening references of included studies and review articles for additional citations. From an initial 150 publications, we included only five studies that met the search criteria. The results showed that anxiety, depression, pain and sleep quality have a great influence on patients' health and on the outcome of the disease. Future studies should focus more on investigating the non-motor components of CD as an integral part of the clinical management of dystonic patients in order to improve their well-being.

What can epidemiological studies teach on the pathophysiology of adult-onset isolated dystonia?

Several demographic and environmental factors may play an important role in determining the risk of developing adult-onset isolated dystonia (AOID) and/or modifying its course. However, epidemiologic studies have provided to date only partial insight on the disease mechanisms that are actively influenced by these factors. The age-related increase in female predominance in both patients diagnosed with AOID and subjects carrying its putative mediational phenotype suggests sexual dimorphism that has been demonstrated for mechanisms related to blepharospasm and cervical dystonia. The opposite relationship that spread and spontaneous remission of AOID have with age suggests age-related decline of compensatory mechanisms that protect from the progression of AOID. Epidemiological studies focusing on environmental risk factors yielded associations only with specific forms of AOID, even for those factors that are not likely to predispose exclusively to specific focal forms (for example, only writing dystonia was found associated with head trauma, and only blepharospasm with coffee intake). Other factors show biological plausibility of their mechanistic role for specific forms, e.g., dry eye syndrome or sunlight exposure for blepharospasm, scoliosis for cervical dystonia, repetitive writing for writing dystonia. Overall, the relationship between environment and AOID remains complex and incompletely defined. Both hypothesis-driven preclinical studies and well-designed cross-sectional or prospective clinical studies are still necessary to decipher this intricate relationship.

How does botulinum toxin really work?

Over the past 30 years, Botulinum toxin (BoNT) has emerged as an effective and safe therapeutic tool for a number of neurological conditions, including dystonia. To date, the exact mechanism of action of BoNT in dystonia is not fully understood. Although it is well known that BoNT mainly acts on the neuromuscular junction, a growing body of evidence suggests that the therapeutic effect of BoNT in dystonia may also depend on its ability to modulate peripheral sensory feedback from muscle spindles. Animal models also suggest a retrograde and anterograde BoNT transportation from the site of injection to central nervous system structures. In humans, however, BoNT central effects seem to depend on the modulation of afferent input rather than on BoNT transportation. In this chapter, we aimed to report and discuss research evidence providing information on the possible mechanisms of action of BoNT in relation to treatment of dystonia.

Physiology of Dystonia: Animal Studies

Dystonia is currently ranked as the third most prevalent motor disorder. It is typically characterized by involuntary muscle over- or co-contractions that can cause painful abnormal postures and jerky movements. Dystonia is a heterogenous disorder-across patients, dystonic symptoms vary in their severity, body distribution, temporal pattern, onset, and progression. There are also a growing number of genes that are associated with hereditary dystonia. In addition, multiple brain regions are associated with dystonic symptoms in both genetic and sporadic forms of the disease. The heterogeneity of dystonia has made it difficult to fully understand its underlying pathophysiology. However, the use of animal models has been used to uncover the complex circuit mechanisms that lead to dystonic behaviors. Here, we summarize findings from animal models harboring mutations in dystonia-associated genes and phenotypic animal models with overt dystonic motor signs resulting from spontaneous mutations, neural circuit perturbations, or pharmacological manipulations. Taken together, an emerging picture depicts dystonia as a result of brain-wide network dysfunction driven by basal ganglia and cerebellar dysfunction. In the basal ganglia, changes in dopaminergic, serotonergic, noradrenergic, and cholinergic signaling are found across different animal models. In the cerebellum, abnormal burst firing activity is observed in multiple dystonia models. We are now beginning to unveil the extent to which these structures mechanistically interact with each other. Such mechanisms inspire the use of pre-clinical animal models that will be used to design new therapies including drug treatments and brain stimulation.

Fixel-Based Analysis Reveals Whole-Brain White Matter Abnormalities in Cervical Dystonia

BACKGROUND

Cervical dystonia (CD) is a form of isolated focal dystonia typically associated to abnormal head, neck, and shoulder movements and postures. The complexity of the clinical presentation limits the investigation of its pathophysiological mechanisms, and the neural networks associated to specific motor manifestations are still the object of debate.

OBJECTIVES

We investigated the morphometric properties of white matter fibers in CD and explored the networks associated with motor symptoms, while regressing out nonmotor scores.

METHODS

Nineteen patients affected by CD and 21 healthy controls underwent diffusion-weighted magnetic resonance imaging. We performed fixel-based analysis, a novel method evaluating fiber orientation within specific fiber bundles, and compared fiber morphometric properties between groups. Moreover, we correlated fiber morphometry with the severity of motor symptoms in patients.

RESULTS

Compared to controls, patients exhibited decreased white matter fibers in the right striatum. Motor symptom severity negatively correlated with white matter fibers passing through inferior parietal areas and the head representation area of the motor cortex.

CONCLUSIONS

Abnormal white matter integrity at the basal ganglia level may affect several functional networks involved, for instance, in motor preparation and execution, visuomotor coordination, and multimodal integration. This may result in progressive maladaptive plasticity, culminating in overt symptoms of dystonia. © 2023 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.

Development of a New Care Pathway for Depression and Anxiety in Adult-Onset Isolated Dystonia

Background

Recently, we identified barriers and facilitators to the screening and treatment of depressive and anxiety symptoms in adult-onset isolated dystonia (AOID). These symptoms are common, functionally impairing, and often underdetected and undertreated.

Objectives

To develop a care pathway for mood symptoms in AOID.

Methods

We used a multistep modified Delphi approach to seek consensus among healthcare professionals with experience of AOID on the screening, diagnosis, and treatment of mood symptoms. A combination of face-to-face meetings and online surveys was performed from 2019 to 2020. We created the survey and then reviewed with stakeholders before 2 rounds of Delphi surveys, all of which was finally reviewed in a consensus meeting. A purposive sample of 41 expert stakeholders from 4 Canadian provinces, including neurologists, nurses, psychiatrists, psychologists, and family physicians, was identified by the research team.

Results

The Delphi process led to consensus on 12 statements that operationalized a pathway of care to screen for and manage depression and anxiety in people with AOID. Key actions of the pathway included yearly screening with self-rated instruments, multidisciplinary involvement in management involving local networks of providers coordinated by movement disorders neurologists, and access to educational resources. The Delphi panel indicated the 2 core steps as the documentation of the most recent screening outcome and the documentation of a management plan for patients who were positive at the last screening.

Conclusions

This new care pathway represents a potentially useful intervention that can be used to build an integrated model of care for AOID.

Mood symptoms in cervical dystonia: Relationship with motor symptoms and quality of life

Background

Cervical dystonia (CD) has a high prevalence of anxiety and depression. The relationship between motor severity, mood symptoms and QoL is unclear and how to adequately assess these is also unknown. Instruments like the BAI, BDI and HADS are often used but items within these relating to somatic symptoms might influence the results.

Methods

Patients with idiopathic cervical dystonia (CD) were included. The BAI, BDI, HADS, CIDP58 and TWSTRS2- severity score were used for assessment of motor, mood and QoL symptoms. Pearson's correlations between motor and non-motor symptom scores were assessed. The psychometric properties of the psychiatric tools were measured and principal component analysis performed after identifying items that could correspond to somatic symptoms.

Results

201 participants were included. 42% of participants had either significant depression or anxiety symptoms or both when measured by BAI and BDI and 51% of patients met criteria on HADS. HADS-A and HADS-D, BAI and BDI were poorly correlated with TWSTRS2-S. The HADS-A and HADS-D both showed strong correlation with the sleep subdomain of CDIP58. Psychometric and principal component analysis on 149/201 participants did not reveal factor loadings consistent with the a priori somatic groupings. However mean scores were higher for somatic items.

Conclusion

A good score on the CDIP58, a commonly used tool, does not indicate mild disease severity or minimal mood symptoms. Minimal motor symptoms, similarly, also does not imply a positive QoL. Clinicians should be mindful on ideal methods for performing a holistic assessment of CD patients. This likely warrants a combination of motor, QoL and mood assessment tools.

Early Onset Dystonia: Complaints about Executive Functioning, Depression and Anxiety

Early Onset Dystonia (EOD) is thought to result from basal ganglia dysfunction, structures also involved in non-motor functions, like regulation of behavior, mood and anxiety. Problems in these domains have been found in proxy-reports but not yet in self-reports of EOD patients. The main questions are whether proxy-reports differ from those of patients and how problems relate to everyday social functioning. Subjective complaints about executive problems (BRIEF) and symptoms of depression and anxiety (CBCL) were obtained through a cross-sectional questionnaire study conducted on 45 EOD patients. Scores were in the normal range in patients and proxies. Proxy-rated behavior regulation was correlated with the estimated number of friends and quality of relations. Proxy-reported scores of depression correlated with the quality of relations and were higher than self-reports of adolescent/young adult patients. EOD patients and proxies do not seem to experience problematic regulation of behavior, mood and anxiety. Still, our study revealed two important aspects: (1) all measures were related to the estimated quality of relations with others, relating questionnaires to everyday social functioning; (2) proxies reported more symptoms of depression than patients. This may indicate overestimation by proxies or higher sensitivity of proxies to these symptoms, implying underestimation of problems by patients.

Gut Microbiome Composition in Dystonia Patients

Dystonia is a movement disorder in which patients have involuntary abnormal movements or postures. Non-motor symptoms, such as psychiatric symptoms, sleep problems and fatigue, are common. We hypothesise that the gut microbiome might play a role in the pathophysiology of the (non-)motor symptoms in dystonia via the gut-brain axis. This exploratory study investigates the composition of the gut microbiome in dystonia patients compared to healthy controls. Furthermore, the abundance of neuro-active metabolic pathways, which might be implicated in the (non-)motor symptoms, was investigated. We performed both metagenomic and 16S rRNA sequencing on the stool samples of three subtypes of dystonia (27 cervical dystonia, 20 dopa-responsive dystonia and 24 myoclonus-dystonia patients) and 25 controls. While microbiome alpha and beta diversity was not different between dystonia patients and controls, dystonia patients had higher abundances of Ruminococcus torques and Dorea formicigenerans, and a lower abundance of Butyrivibrio crossotus compared to controls. For those with dystonia, non-motor symptoms and the levels of neurotransmitters in plasma explained the variance in the gut microbiome composition. Several neuro-active metabolic pathways, especially tryptophan degradation, were less abundant in the dystonia patients compared to controls. This suggest that the gut-brain axis might be involved in the pathophysiology of dystonia. Further studies are necessary to confirm our preliminary findings.

The Collicular-Pulvinar-Amygdala Axis and Adult-Onset Idiopathic Focal Dystonias

Adult-onset idiopathic focal dystonias (AOIFD) are the most common type of dystonia. It has varied expression including multiple motor (depending on body part affected) and non-motor symptoms (psychiatric, cognitive and sensory). The motor symptoms are usually the main reason for presentation and are most often treated with botulinum toxin. However, non-motor symptoms are the main predictors of quality of life and should be addressed appropriately, as well as treating the motor disorder. Rather than considering AOIFD as a movement disorder, a syndromic approach should be taken, one that accommodates all the symptoms. Dysfunction of the collicular-pulvinar-amygdala axis, with the superior colliculus as a central node, can explain the diverse expression of this syndrome.

Isolated and combined dystonias: Update

Dystonia is a hyperkinetic movement disorder with a unique motor phenomenology that can manifest as an isolated clinical syndrome or combined with other neurological features. This chapter reviews the characteristic features of dystonia phenomenology and the syndromic approach to evaluating the disorders that may allow us to differentiate the isolated and combined syndromes. We also present the most common types of isolated and combined dystonia syndromes. Since accelerated gene discoveries have increased our understanding of the molecular mechanisms of dystonia pathogenesis, we also present isolated and combined dystonia syndromes by shared biological pathways. Examples of these converging mechanisms of the isolated and combined dystonia syndromes include (1) disruption of the integrated response pathway through eukaryotic initiation factor 2 alpha signaling, (2) disease of dopaminergic signaling, (3) alterations in the cerebello-thalamic pathway, and (4) disease of protein mislocalization and stability. The discoveries that isolated and combined dystonia syndromes converge in shared biological pathways will aid in the development of clinical trials and therapeutic strategies targeting these convergent molecular pathways.

Impact of Depression on Cognitive Function and Disease Severity in Idiopathic Cervical Dystonia Patients: One-Center Data in Cross-Sectional Study

Background: Cervical dystonia is a highly disabling hyperkinetic movement disorder with a lot of nonmotor symptoms. One symptom with a high prevalence is depression, which may negatively affect dystonia patients. The aim of the study was to investigate the impact of depression on disease severity and cognitive functions in cervical dystonia patients. Methods: Patients with cervical dystonia were interviewed and divided into two groups, based on the Patient Health Questionnaire-9: those with no depression or mild depressive features and those with moderate, moderately severe, and severe depression. The severity of dystonia and cognitive functions were assessed and compared in both groups. Results: A total of 52 patients were investigated. Self-assessment of the disease was more negative in clinically significant depressive signs group (p = 0.004), with a tendency for patients with clinically significant depressive features to have a slightly higher score on objective dystonia scales (TSUI and TWSTRS), but without statistically significant differences (p = 0.387 and p = 0.244, respectively). Although not statistically significant, a slightly higher MoCA scale score was registered in cervical dystonia patients with clinically insignificant depressive signs. There was a tendency for worse results in the abstraction category in patients with clinically significant depression (p = 0.056). Conclusions: Patients with clinically significant depression have a more negative self-assessment of the disease and perform worse in abstraction tasks.

Cognitive and Neuropsychiatric Impairment in Dystonia

PURPOSE OF REVIEW

To review recent literature evaluating psychiatric and cognitive symptoms in dystonia, the two non-motor symptom groups most frequently evaluated in dystonia research and recognised in clinical practice.

RECENT FINDINGS

Recent work has embedded clinical recognition of psychiatric symptoms in dystonia, with depressive and anxiety-related symptoms routinely observed to be the most common. Less explored symptoms, such as self-harm, suicidal ideation, and substance abuse, represent newer areas of investigation, with initial work suggesting higher rates than the background population. Investigation of cognitive function has provided less consistent results, both within individual dystonia subtypes and across the spectrum of dystonias, partly reflecting the heterogeneity in approaches to assessment. However, recent work indicates impairments of higher cognitive function, e.g. social cognition, and disrupted visual and auditory sensory processing. Dystonia demonstrates psychiatric and cognitive symptom heterogeneity, with further work needed to recognise endophenotypes and improve diagnostic accuracy, symptom recognition, and management.

Effects of Botulinum Toxin Therapy on Health-Related Quality of Life Evaluated by the Oromandibular Dystonia Rating Scale

Oromandibular dystonia (OMD) refers to a focal dystonia in the stomatognathic system. Health-related quality of life (HRQoL) in isolated dystonia is associated with non-motor symptoms such as depression, anxiety, and pain, as well as motor symptoms. To evaluate HRQoL in patients with OMD, the therapeutic effects of botulinum neurotoxin (BoNT) therapy were assessed using a recently developed and validated comprehensive measurement tool called the Oromandibular Dystonia Rating Scale (OMDRS). Altogether, 408 patients (jaw closing dystonia, n = 223; tongue (lingual) dystonia, n = 86; jaw opening dystonia, n = 50; jaw deviation dystonia, n = 23; jaw protrusion dystonia, n = 13; and lip (labial) dystonia, n = 13) were evaluated at baseline and after the end of BoNT therapy or in a stable status. The total OMDRS score reduced significantly from 149.1 to 57.6 (p < 0.001). Mean improvement was 63.1%. All examiner-rated subscales (severity, disability, and pain) and patient-rated questionnaire scores (general, eating, speech, cosmetic, social/family life, sleep, annoyance, mood, and psychosocial function) were significantly lower at the endpoint than at baseline (p < 0.001). The BoNT injection had a highly positive impact on patient HRQoL, and the OMDRS could evaluate both motor phenomena and non-motor symptoms.

A Clinical Approach to Focal Dystonias

Dystonia is a hyperkinetic movement disorder (HMD), characterised by sustained or intermittent involuntary muscle contractions resulting in abnormal postures and/or movements [1]. Although primary dystonia has an estimated prevalence of 16 per 100,000 [2], the diagnosis may be delayed, due to its clinical heterogeneity, the lack of objective biomarkers and the potential for pseudodystonic conditions to mimic it [1,3]. We provide an overview of the classification and common subtypes of focal dystonia, focusing on the clinical phenomenology and diagnosis.

Comprehensive analysis of non-motor symptoms and their association with quality of life in Writer's cramp

OBJECTIVE

Limited studies have focused on non-motor symptoms (NMS) in patients with Writer's cramp (WC). The current study aimed to examine the frequency of NMS and their association with health-related quality of life (HR-QoL) in patients with WC.

METHODS

A total of 80 patients with WC and 69 healthy controls (HCs) were enrolled. Motor symptoms was assessed by Burke-Fahn-Marsden dystonia rating scale and NMS was evaluated through several specific scales, including Hamilton depression rating scale-24 items (HDRS-24), Hamilton anxiety rating scale, Epworth sleepiness scale, Pittsburgh sleep quality index, fatigue severity scale (FSS), numerical rating scale for pain, and Montreal cognitive assessment. The HR-QoL was assessed using 36-item short form health survey (SF-36), which can be divided into physical component summary (PCS) and mental component summary (MCS). Multiple linear regression was used to analysis the association between each NMS and HR-QoL.

RESULTS

The patients presented more symptoms of depression, anxiety, poor quality of sleep, excessive daytime sleepiness, and fatigue than the HCs. The most frequent NMS in patients with WC was anxiety (51.25%) and depression (46.25%) symptoms. We found that motor symptoms had no association with HR-QoL. Higher scores of HDRS-24 were associated with lower scores of SF-36 in PCS and MCS. Meantime, higher scores of FSS were significantly associated with lower scores of SF-36 in MCS.

CONCLUSION

The NMS was prevalent in patients with WC, with frequent anxiety and depression symptoms. Depression symptoms and fatigue had a strongly negative impact on HR-QoL and deserve attention in clinic practice.

Dystonia, chorea, hemiballismus and other dyskinesias

Hyperkinesias are heterogeneous involuntary movements that significantly differ in terms of clinical and semeiological manifestations, including rhythm, regularity, speed, duration, and other factors that determine their appearance or suppression. Hyperkinesias are due to complex, variable, and largely undefined pathophysiological mechanisms that may involve different brain areas. In this chapter, we specifically focus on dystonia, chorea and hemiballismus, and other dyskinesias, specifically, levodopa-induced, tardive, and cranial dyskinesia. We address the role of neurophysiological studies aimed at explaining the pathophysiology of these conditions. We mainly refer to human studies using surface and invasive in-depth recordings, as well as spinal, brainstem, and transcortical reflexology and non-invasive brain stimulation techniques. We discuss the extent to which the neurophysiological abnormalities observed in hyperkinesias may be explained by pathophysiological models. We highlight the most relevant issues that deserve future research efforts. The potential role of neurophysiological assessment in the clinical context of hyperkinesia is also discussed.

Low-Intensity Transcranial Ultrasound Stimulation: Mechanisms of Action and Rationale for Future Applications in Movement Disorders

Low-intensity transcranial ultrasound stimulation (TUS) is a novel non-invasive brain stimulation technique that uses acoustic energy to induce changes in neuronal activity. However, although low-intensity TUS is a promising neuromodulation tool, it has been poorly studied as compared to other methods, i.e., transcranial magnetic and electrical stimulation. In this article, we first focus on experimental studies in animals and humans aimed at explaining its mechanisms of action. We then highlight possible applications of TUS in movement disorders, particularly in patients with parkinsonism, dystonia, and tremor. Finally, we highlight the knowledge gaps and possible limitations that currently limit potential TUS applications in movement disorders. Clarifying the potential role of TUS in movement disorders may further promote studies with therapeutic perspectives in this field.

Illness Perceptions, Coping, Health-Related Quality of Life and Psychological Outcomes in Cervical Dystonia

This study examined the predictive ability of the Common-Sense Model to explain psychological outcomes in cervical dystonia, a movement disorder that affects the muscles of the head and neck. Illness Perceptions Questionnaire-Revised, brief COPE, Hospital Anxiety and Depression Scale, Cervical Dystonia Impact Profile and the Post-Traumatic Growth Inventory were completed by 118 people with cervical dystonia. Correlations and hierarchical multiple regression models were conducted. Illness perceptions and coping strategies explained 59% of variance in anxiety, 61% of variance in depression and health-related quality of life and 19% of variance in post-traumatic growth. Illness perceptions and coping strategies are significant factors to consider in terms of psychological adjustment and outcomes in cervical dystonia. Psychological interventions targeting illness perceptions and coping strategies may be beneficial in improving psychological outcomes for people with cervical dystonia.

Neuroplasticity in dystonia: Motor symptoms and beyond

This chapter first focuses on the role of altered neuroplasticity mechanisms and their regulation in the genesis of motor symptoms in the various forms of dystonia. In particular, a review of the available literature about focal dystonia suggests that use-dependent plasticity may become detrimental and produce dystonia when practice and repetition are excessive and predisposing conditions are present. Interestingly, recent evidence also shows that functional or psychogenic dystonia, despite the normal plasticity in the sensorimotor system, is characterized by plasticity-related dysfunction within limbic regions. Finally, this chapter reviews the non-motor symptoms that often accompany the motor features of dystonia, including depression and anxiety as well as obsessive-compulsive disorders, pain, and cognitive dysfunctions. Based on the current understanding of these symptoms, we discuss the evidence of their possible relationship to maladaptive plasticity in non-motor basal ganglia circuits involved in their genesis.

A Cross-Cultural Validation of the Filipino and Hiligaynon Versions of the Parts IIIB (Non-Motor Features) and IV (Activities of Daily Living) of the X-Linked Dystonia-Parkinsonism- MDSP Rating Scale

Introduction

X-linked dystonia-parkinsonism (XDP) is a progressive movement disorder which also encompasses non-motor features and alterations in activities of daily living. The study aims to translate the Parts IIIB (Non-Motor Features) and IV (Activities of Daily Living) of the XDP-Movement Disorder Society of Philippines Rating Scale to Filipino and Hiligaynon and subsequently validate these versions, which are more understandable to the natives given that XDP originated from the Panay Islands in the Philippines.

Methods

This is a cross-cultural, cross-sectional validation study, composed of the following steps: forward translation, backward translation, panel reconciliation, pretesting, and field testing. Two sets of 10 XDP patients were recruited to the Filipino and Hiligaynon groups for pretesting and cognitive debriefing while another 2 sets of 50 XDP patients were assigned for field testing.

Results

The Filipino version had a good internal consistency with a Cronbach's alpha of 0.951 during the pretesting and 0.886 during the field testing. Similar results were seen in the Hiligaynon version (0.837; 0.900). Both also had good conceptual equivalence as demonstrated by significant Pearson r values of 0.384 to 0.814 for the Filipino and 0.355 to 0.800 for the Hiligaynon versions.

Conclusion

The Filipino and Hiligaynon versions of the Parts IIIB and IV of the XDP-MDSP scale are internally valid and reliable. These scales are considered acceptable to assess the severity of the non-motor features and difficulties in activities of daily living among XDP patients.

Exploring the presence of multiple abnormal non-motor features in patients with cervical dystonia

This study's aim was to investigate prevalence of four non-motor symptoms in patients with cervical dystonia and healthy controls to explore whether the presence of multiple non-motor features is associated with cervical dystonia diagnosis. Fifteen patients with cervical dystonia and 15 healthy controls underwent non-invasive testing of spatial discrimination threshold, temporal discrimination threshold, vibration-induced illusion of movement, and kinesthesia. All spatial discrimination threshold, temporal discrimination threshold, and vibration-induced illusion of movement measures were converted to standardized Z scores with scores >2.0 considered abnormal. Any incorrect kinesthesia response was considered abnormal. Prevalence of each abnormal non-motor feature was compared between groups using a chi-squared test. A higher proportion of patients with cervical dystonia had abnormal spatial discrimination threshold (p = 0.01) and abnormal kinesthesia (p = 0.03) scores compared to healthy control subjects. There were no significant differences between the proportion of patients with cervical dystonia versus healthy controls for abnormal temporal discrimination threshold (p = 0.07) or abnormal vibration-induced illusion of movement (p = 0.14). Forty-seven percent of patients with cervical dystonia (7/15) demonstrated one abnormal non-motor feature, 20% (3/15) displayed two abnormal features, and 13% (2/15) displayed three abnormal features. Kinesthesia was the only non-motor feature identified as abnormal in the control group (20%, 3/15). All four tests demonstrated high specificity (80-100%) and low-moderate sensitivity (13-60%). These findings suggest that non-motor feature testing, specifically for spatial discrimination threshold and kinesthesia, could be a highly specific diagnostic tool to inform cervical dystonia diagnosis. Further investigation is needed to confirm these findings.

Movement disorders in patients with Rett syndrome: A systematic review of evidence and associated clinical considerations

AIM

This systematic review identified and thematically appraised clinical evidence of movement disorders in patients with Rett syndrome (RTT).

METHOD

Using PRISMA criteria, six electronic databases were searched from inception to April 2021. A thematic analysis was then undertaken on the extracted data to identify potential themes.

RESULTS

Following the thematic analysis, six themes emerged: (i) clinical features of abnormal movement behaviors; (ii) mutational profile and its impact on movement disorders; (iii) symptoms and stressors that impact on movement disorders; (iv) possible underlying neurobiological mechanisms; (v) quality of life and movement disorders; and (vi) treatment of movement disorders. Current guidelines for managing movement disorders in general were then reviewed to provide possible treatment recommendations for RTT.

CONCLUSION

Our study offers an enriched data set for clinical investigations and treatment of fine and gross motor issues in RTT. A detailed understanding of genotype-phenotype relationships of movement disorders allows for more robust genetic counseling for families but can also assist healthcare professionals in terms of monitoring disease progression in RTT. The synthesis also showed that environmental enrichment would be beneficial for improving some aspects of movement disorders. The cerebellum, basal ganglia, alongside dysregulation of the cortico-basal ganglia-thalamo-cortical loop, are likely anatomical targets. A review of treatments for movement disorders also helped to provide recommendations for treating and managing movement disorders in patients with RTT.

Sensitivity and pain in focal dystonia of the hand

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.

Comparing Brain Functional Activities in Patients With Blepharospasm and Dry Eye Disease Measured With Resting-State fMRI

Background: Blepharospasm (BSP) and dry eye disease (DED) are clinically common diseases characterized by an increased blinking rate. A sustained eyelid muscle activity may alter the cortical sensorimotor concordance and lead to secondary functional changes. This study aimed to explore the central mechanism of BSP by assessing brain functional differences between the two groups and comparing them with healthy controls.

Methods: In this study, 25 patients with BSP, 22 patients with DED, and 23 healthy controls underwent resting-state functional magnetic resonance imaging (fMRI) scan. The amplitude of low-frequency fluctuations (ALFF) was applied to analyze the imaging data.

Results: Analysis of covariance (ANCOVA) revealed widespread differences in ALFF across the three groups. In comparison with healthy controls, patients with BSP showed abnormal ALFF in the sensorimotor integration related-brain regions, including the bilateral supplementary motor area (SMA), left cerebellar Crus I, left fusiform gyrus, bilateral superior medial prefrontal cortex (MPFC), and right superior frontal gyrus (SFG). In comparison with patients with DED, patients with BSP exhibited a significantly increased ALFF in the left cerebellar Crus I and left SMA. ALFF in the left fusiform gyrus/cerebellar Crus I was positively correlated with symptomatic severity of BSP.

Conclusions: Our results reveal that the distinctive changes in the brain function in patients with BSP are different from those in patients with DED and healthy controls. The results further emphasize the primary role of sensorimotor integration in the pathophysiology of BSP.

Mental health and behaviour in children with dystonia: Anxiety, challenging behaviour and the relationship to pain and self-esteem

PURPOSE

To ascertain whether young people with dystonia are more likely than the general population to have mental health and/or behavioural difficulties, and to explore factors that may contribute to these difficulties.

METHOD

Using a quasi-experimental design, 50 young people with dystonia aged 7-17 and their carers were recruited from the Evelina London Children's Hospital. Young people completed the Beck Youth Inventories and the Strengths and Difficulties Questionnaire. Carers completed the Strengths and Difficulties Questionnaire-Parent version and the Paediatric Pain Profile. Important medical factors, such as age of onset, motor severity and manual function were obtained from medical records.

RESULTS

One sample z tests showed young people with dystonia self-reported significantly higher levels of anxiety (p < .001) and prosocial difficulties (p < .01), with 48% experiencing clinically significant anxiety levels. They experienced significantly lower levels of anger, disruptive behaviour and conduct problems (all p ≤ .01). Carers reported significantly higher rates of emotional problems, hyperactivity and peer problems, and significantly lower prosocial behaviours (all p ≤ .01). Pearson's correlation coefficients showed lower levels of self-esteem were related to higher levels of anxiety (p = .015). High levels of pain were related to parent-rated conduct problems (p = .004). Age of dystonia onset and motor severity did not correlate with any of the psychological or behavioural measures.

INTERPRETATION/CONCLUSIONS

Our study suggests high rates of anxiety and behaviours that challenge in children with dystonia. Screening in movement clinics would be helpful in early identification and signposting for support.

Identifying Depressed Essential Tremor Using Resting-State Voxel-Wise Global Brain Connectivity: A Multivariate Pattern Analysis

Background and Objective: Although depression is one of the most common non-motor symptoms in essential tremor (ET), its pathogenesis and diagnosis biomarker are still unknown. Recently, machine learning multivariate pattern analysis (MVPA) combined with connectivity mapping of resting-state fMRI has provided a promising way to identify patients with depressed ET at the individual level and help to reveal the brain network pathogenesis of depression in patients with ET.

Methods: Based on global brain connectivity (GBC) mapping from 41 depressed ET, 49 non-depressed ET, 45 primary depression, and 43 healthy controls (HCs), multiclass Gaussian process classification (GPC) and binary support vector machine (SVM) algorithms were used to identify patients with depressed ET from non-depressed ET, primary depression, and HCs, and the accuracy and permutation tests were used to assess the classification performance.

Results: While the total accuracy (40.45%) of four-class GPC was poor, the four-class GPC could discriminate depressed ET from non-depressed ET, primary depression, and HCs with a sensitivity of 70.73% (P < 0.001). At the same time, the sensitivity of using binary SVM to discriminate depressed ET from non-depressed ET, primary depression, and HCs was 73.17, 80.49, and 75.61%, respectively (P < 0.001). The significant discriminative features were mainly located in cerebellar-motor-prefrontal cortex circuits (P < 0.001), and a further correlation analysis showed that the GBC values of significant discriminative features in the right middle prefrontal gyrus, bilateral cerebellum VI, and Crus 1 were correlated with clinical depression severity in patients with depressed ET.

Conclusion: Our findings demonstrated that GBC mapping combined with machine learning MVPA could be used to identify patients with depressed ET, and the GBC changes in cerebellar-prefrontal cortex circuits not only posed as the significant discriminative features but also helped to understand the network pathogenesis underlying depression in patients with ET.

Pain in cervical dystonia: mechanisms, assessment and treatment

INTRODUCTION

In patients with cervical dystonia (CD), pain is a major contributor to disability and social isolation and is often the main reason patients seek treatment. Surveys evaluating patient perceptions of their CD symptoms consistently highlight pain as a troublesome and disabling feature of their condition with significant impact on daily life and work.

AREAS COVERED

In this article, the authors review the epidemiology, assessment, possible mechanisms and treatment of pain in CD, including a meta-analysis of randomized controlled trial data with abobotulinumtoxinA.

EXPERT OPINION

Mechanisms of pain in CD may be muscle-based and non-muscle based. Accumulating evidence suggests that non-muscle-based mechanisms (such as abnormal transmission and processing of nociceptive stimuli, dysfunction of descending pain inhibitory pathways as well as structural and network changes in the basal ganglia, cortex and other areas) may also contribute to pain in CD alongside prolonged muscle contraction. Chemodenervation with botulinum toxin is considered the first-line treatment for CD. Treatment with botulinum toxin is usually effective, but optimization of the injection parameters should include consideration of pain as a core symptom in addition to the motor problems.

Effect of Botulinum Toxin on Non-Motor Symptoms in Cervical Dystonia

Patients with cervical dystonia (CD) may display non-motor symptoms, including psychiatric disturbances, pain, and sleep disorders. Intramuscular injection of botulinum toxin type A (BoNT-A) is the most efficacious treatment for motor symptoms in CD, but little is known about its effects on non-motor manifestations. The aim of the present study was to longitudinally assess BoNT-A’s effects on CD non-motor symptoms and to investigate the relationship between BoNT-A-induced motor and non-motor changes. Forty-five patients with CD participated in the study. Patients underwent a clinical assessment that included the administration of standardized clinical scales assessing dystonic symptoms, psychiatric disturbances, pain, sleep disturbances, and disability. Clinical assessment was performed before and one and three months after BoNT-A injection. BoNT-A induced a significant improvement in dystonic symptoms, as well as in psychiatric disturbances, pain, and disability. Conversely, sleep disorders were unaffected by BoNT-A treatment. Motor and non-motor BoNT-A-induced changes showed a similar time course, but motor improvement did not correlate with non-motor changes after BoNT-A. Non-motor symptom changes after BoNT-A treatment are a complex phenomenon and are at least partially independent from motor symptom improvement.

Sleep and other Non-motor Symptoms in Patients with Idiopathic Oromandibular Dystonia and Meige Syndrome: A Questionnaire-based Study

Introduction:

Non-motor symptoms are an essential cause of comorbidity in generalized and focal dystonia. However, there are few studies on dystonia involving the craniofacial regions.

Methods:

We studied non-motor symptoms in patients with oromandibular dystonia (OMD) and Meige syndrome using a questionnaire, and validated instruments for depression, anxiety, REM behaviour disorder, restless leg syndrome, sleep quality, excessive daytime sleepiness, and self-esteem. The severity of dystonia and blepharospasm was also studied.

Results:

Nineteen patients with OMD were recruited into the study. Among patients with OMD, depression was seen in 63.6% (n = 7), sleep impairment in 27.3% (n = 3), excessive daytime sleepiness in 27.3% (n = 3), and poor self- esteem in 18.2% (n = 2) of the patients. Among patients with Meige syndrome, depression was seen in 37.5% (n = 3), sleep impairment in 12.5% (n = 1), excessive daytime sleepiness in 25% (n = 2), low self-esteem in 25% (n = 2) of the patients.

Conclusion:

This study highlights the significant frequency of depression and sleep disturbances in patients with idiopathic OMD and Meige syndrome.