Remission in dystonia - Systematic review of the literature and meta-analysis

Contextual effects: how to, and how not to, quantify them

The importance of contextual effects and their roles in clinical care controversial. A Cochrane review published in 2010 concluded that placebo interventions lack important clinical effects overall, but that placebo interventions can influence patient-reported outcomes such as pain and nausea. However, systematic reviews published after 2010 estimated greater contextual effects than the Cochrane review, which stems from the inappropriate methods employed to quantify contextual effects. The effects of medical interventions (i.e., the total treatment effect) can be divided into three components: specific, contextual, and non-specific. We propose that the most effective method for quantifying the magnitude of contextual effects is to calculate the difference in outcome measures between a group treated with placebo and a non-treated control group. Here, we show that other methods, such as solely using the placebo control arm or calculation of a 'proportional contextual effect,' are limited and should not be applied. The aim of this study is to provide clear guidance on best practices for estimating contextual effects in clinical research.

A look at the future-new BoNTs and delivery systems in development: What it could mean in the clinic

Despite the expanding clinical utility of botulinum neurotoxins, there remain problems to be solved for attaining the best outcome. The efficacy and safety need to be reconsidered for commercially available preparations all derived from subtype A1 or B1. Emerging new toxins include A2 or A6 subtypes or engineered toxins with less spread, more potency, longer durations of action, less antigenicity and better safety profile than currently used preparations. Non-toxic BoNTs with a few amino acid replacements of the light chain (LC) may have a role as a drug-delivery system if the toxicity is abolished entirely. At present, efficacy of these BoNTs in animal botulism was demonstrated.

Improving the Efficacy of Botulinum Toxin for Cervical Dystonia: A Scoping Review

Cervical dstonia (CD) is a chronic disorder with a significant detrimental impact on quality of life, requiring long-term treatment. Intramuscular injections of botulinum neurotoxin (BoNT) every 12 to 16 weeks have become the first-line option for CD. Despite the remarkable efficacy of BoNT as a treatment for CD, a significantly high proportion of patients report poor outcomes and discontinue the treatment. The reasons that drive sub-optimal response or treatment failure in a proportion of patients include but are not limited to inappropriate muscle targets and/or BoNT dosing, improper method of injections, subjective feeling of inefficacy, and the formation of neutralizing antibodies against the neurotoxin. The current review aims to complement published research focusing on the identification of the factors that might explain the failure of BoNT treatment in CD, highlighting possible solutions to improve its outcomes. Thus, the use of the new phenomenological classification of cervical dystonia known as COL-CAP might improve the identification of the muscle targets, but more sensitive information might come from the use of kinematic or scintigraphic techniques and the use of electromyographic or ultrasound guidance might ensure the accuracy of the injections. Suggestions are made for the development of a patient-centered model for the management of cervical dystonia and to emphasize that unmet needs in the field are to increase awareness about the non-motor spectrum of CD, which might influence the perception of the efficacy from BoNT injections, and the development of dedicated rehabilitation programs for CD that might enhance its effectiveness.

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.

What have we learned about the biology of dystonia from deep brain stimulation?

Deep brain stimulation has dramatically changed the management of patients with dystonia, therapeutic approach of dystonia with marked improvement of dystonia and functional disability. However, despite decades of experience and identification of good prognosis factors, prediction of beneficial effect at the individual level is still a challenge. There is inter-individual variability in therapeutic outcome. Genetic factors are identified but subgroups of patients still have relapse or worsening of dystonia in short or long term. Possible "biological factors" underlying such a difference among patients are discussed, including structural or functional differences including altered plasticity.

Is There a Standard Rehabilitation Procedure in Cervical Dystonia?

Introduction: Idiopathic cervical dystonia, also known as spasmodic torticollis, is the most common form of focal dystonia in adults. Cervical dystonia usually appears between the ages of 30 and 50, twice as often in women, and is characterised by uncontrollable painful contractions of the sternocleidomastoid muscle, which results in misalignment of the head and shoulder. Over time, the disease becomes very burdensome for the patient and reduces his/her independence and quality of life; falls happen.Aim: The aim of the article is to present the current state of knowledge on comprehensive rehabilitation in cervical dystonia. Data on the prevalence, symptoms, diagnosis, clinical assessment, pharmacological treatment (including the most commonly used botulinum toxin), neurosurgical treatment and comprehensive rehabilitation are presented.Methods: The applied methods was a narrative critical review of scientific reports.Results: Out of several hundred publications, works worthy of particular attention were selected. In them, are described of conducting exercises, the main goal of which is to stretch and relax the dystonic muscles while strengthening the antagonistic muscles and correcting the position of the head. The selected authors used manual therapy, exercises at the patient's home, EMG biofeedback, magnetic stimulation of the cerebellum, vibration of the neck muscles, functional electrostimulation (FES) of antagonistic muscles, mobilisation of the cervical spine, postural exercises, isometric exercises, muscle relaxation, the PNF method, relaxation training, balance exercises, coordination, corrective exercises, massage, relaxation exercises, stretching and kinesiotaping.Conclusions: The variety of disease forms (10 head positioning patterns are described) and different severity of symptoms make it impossible to draw up a scheme of rehabilitation. In each case, rehabilitation must be tailored individually, and the physiotherapist taking care of the patient should have extensive experience. Physiotherapy can alleviate the disability caused by dystonia, however, due to the many non-motor symptoms, a holistic approach to the patient should also be kept in mind.

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.

Efficacy and safety of long-term botulinum toxin treatment for acquired cervical dystonia: a 25-year follow-up

Botulinum toxin A (BoNT/A) is the first-line treatment for idiopathic cervical dystonia (ICD) and is widely used in the clinical setting. To date, scanty data are available on the effectiveness of BoNT in treating acquired cervical dystonia (ACD). Here we present a long-term follow-up of ACD patients treated with BoNT/A that focused on safety and efficacy. The study included subjects who had received at least six treatments of three commercially available BoNT/A drugs [abobotulinumtoxinA (A/Abo), incobotulinumtoxinA (A/Inco) and onabotulinumtoxinA (A/Ona)]. Safety and efficacy were assessed based on patients' self-reports regarding adverse effects (AE), duration of improvement of dystonia and/or pain relief. Global clinical improvement was measured on a six-point scale. 23 patients with ACD were administered 739 treatments (A/Abo in 235, A/Inco in 72, A/Ona in 432) with a mean number of treatments of 31 ± 20 (range 6-76) and duration of 10 ± 6 weeks (range 2-25). The mean dose was 737 ± 292 U for A/Abo, 138 ± 108 U for A/Inco and 158 ± 80 U for A/Ona. The average benefit duration was 89 ± 26 (A/Abo), 88 ± 30 days (A/Inco), and 99 ± 55 days (A/Ona) (p = 0.011); global clinical improvement for all sessions was 4 ± 1. ANOVA one-way analysis indicated that A/Ona had the best profile in terms of duration (p < 0.05), whereas A/Abo had the best pain relief effect (p = 0.002). Side effects were reported in 9% of treatments (67/739), with ten treatments (1%) complicated by two side effects. Most side effects were rated mild to moderate; severe side effects occurred following three treatments with the three different BoNT; two required medical intervention. No allergic reactions were reported. Even after 25 years of repeated treatments, all serotypes of BoNT demonstrate positive effects in treating ACD with long-lasting efficacy and safety.

The Dystonias

PURPOSE OF REVIEW

This article discusses the most recent findings regarding the diagnosis, classification, and management of genetic and idiopathic dystonia.

RECENT FINDINGS

A new approach to classifying dystonia has been created with the aim to increase the recognition and diagnosis of dystonia. Molecular biology and genetic studies have identified several genes and biological pathways involved in dystonia.

SUMMARY

Dystonia is a common movement disorder involving abnormal, often twisting, postures and is a challenging condition to diagnose. The pathophysiology of dystonia involves abnormalities in brain motor networks in the context of genetic factors. Dystonia has genetic, idiopathic, and acquired forms, with a wide phenotypic spectrum, and is a common feature in complex neurologic disorders. Dystonia can be isolated or combined with another movement disorder and may be focal, segmental, multifocal, or generalized in distribution, with some forms only occurring during the performance of specific tasks (task-specific dystonia). Dystonia is classified by clinical characteristics and presumed etiology. The management of dystonia involves accurate diagnosis, followed by treatment with botulinum toxin injections, oral medications, and surgical therapies (mainly deep brain stimulation), as well as pathogenesis-directed treatments, including the prospect of disease-modifying or gene therapies.

The Impact of the Course of Disease before Botulinum Toxin Therapy on the Course of Treatment and Long-Term Outcome in Cervical Dystonia

This study analyses the influence of the course of the disease of idiopathic cervical dystonia (CD) before botulinum toxin (BoNT) therapy on long-term outcomes. 74 CD-patients who were treated on a regular basis in the botulinum toxin outpatient department of the University of Düsseldorf and had received at least 3 injections were consecutively recruited after written informed consent. Patients were asked to rate the amount of change of CD in relation to the severity of CD at begin of BoNT therapy (IMPQ). Then they had to draw the course of disease of CD from onset of symptoms until initiation of BoNT therapy (CoDB-graph) on a sheet of paper into a square of 10 × 10 cm² size. Remaining severity of CD was estimated by the treating physician using the TSUI-score. Demographical and treatment related data were extracted from the charts of the patients. Depending on the curvature four different types of CoDB-graphs could be distinguished. Time to BoNT therapy, increase of dose and improvement during BoNT treatment were significantly (p < 0.05) different when patients were split up according to CoDB-graph types. The lower the age at onset of symptoms, the shorter was the time to therapy (p < 0.02). Initial dose (p < 0.04) and actual dose (p < 0.009) were negatively correlated with the age of the patients at recruitment. The course of disease of CD before BoNT therapy has influence on long-term outcome. This has implications on patient management and information on the efficacy of BoNT treatment.

Functional dystonia: A case-control study and risk prediction algorithm

OBJECTIVE

Functional dystonia (FD) is a disabling and diagnostically challenging functional movement disorder (FMD). We sought to identify historical predictors of FD vs. other primary dystonias (ODs) and develop a practical prediction algorithm to guide neurologists.

METHODS

1475 consecutive new patient medical records were reviewed at an adult/pediatric tertiary-referral dystonia clinic from 2005 to 2017. Ninety-nine met criteria for clinically established FD (85 adults and 14 pediatric), paired with 99 age/dystonia distribution-matched OD. Univariate and multivariate regression analyses were performed to identify predictors of FD and disability. We formed a prediction algorithm, assessed using the area under the receiver operating curve (AUC).

RESULTS

Multivariate logistic regression analysis investigating independent predictors of FD (P < 0.001) followed by development of a prediction algorithm showed that the most robust predictors included abrupt onset, spontaneous resolution/recurrence, pain, cognitive complaints, being on or pursuing disability, lifetime mood/anxiety disorder, comorbid functional somatic disorders, and having ≥3 medication allergies. The prediction algorithm had utility for both adult and pediatric FD, with excellent sensitivity/specificity (89%/92%) and an area under the curve (AUC) 0.95 (0.92-0.98). Greater disability (modified Rankin Scale) independently correlated with a number of functional examination features, unemployment/not attending school, number of medication allergies, and younger age of presentation. FD patients were high health-care utilizers and were more frequently prescribed opiates/opioids and benzodiazepines (P < 0.003).

INTERPRETATION

This case-control study provides an algorithm to guide clinicians in gauging their index of suspicion for a FD, with diagnostic confirmation subsequently informed by neurological examination. While this algorithm requires prospective validation, health-care utilization data underscore the importance and need for more research in FD.

Functional Dystonia: Differentiation From Primary Dystonia and Multidisciplinary Treatments

Dystonia is a common movement disorder, involving sustained muscle contractions, often resulting in twisting and repetitive movements and abnormal postures. Dystonia may be primary, as the sole feature (isolated) or in combination with other movement disorders (combined dystonia), or as one feature of another neurological process (secondary dystonia). The current hypothesis is that dystonia is a disorder of distributed brain networks, including the basal ganglia, cerebellum, thalamus and the cortex resulting in abnormal neural motor programs. In comparison, functional dystonia (FD) may resemble other forms of dystonia (OD) but has a different pathophysiology, as a subtype of functional movement disorders (FMD). FD is the second most common FMD and amongst the most diagnostically challenging FMD subtypes. Therefore, distinguishing between FD and OD is important, as the management of these disorders is distinct. There are also different pathophysiological underpinnings in FD, with for example evidence of involvement of the right temporoparietal junction in functional movement disorders that is believed to serve as a general comparator of internal predictions/motor intentions with actual motor events resulting in disturbances in self-agency. In this article, we present a comprehensive review across the spectrum of FD, including oromandibular and vocal forms and discuss the history, clinical clues, evidence for adjunctive "laboratory-based" testing, pathophysiological research and prognosis data. We also provide the approach used at the Massachusetts General Hospital Dystonia Center toward the diagnosis, management and treatment of FD. A multidisciplinary approach, including neurology, psychiatry, physical, occupational therapy and speech therapy, and cognitive behavioral psychotherapy approaches are frequently required; pharmacological approaches, including possible targeted use of botulinum toxin injections and inpatient programs are considerations in some patients. Early diagnosis and treatment may help prevent unnecessary investigations and procedures, while facilitating the appropriate management of these highly complex patients, which may help to mitigate frequently poor clinical outcomes.

Botulinum Toxin in Movement Disorders: An Update

Since its initial approval in 1989 by the US Food and Drug Administration for the treatment of blepharospasm and other facial spasms, botulinum toxin (BoNT) has evolved into a therapeutic modality for a variety of neurological and non-neurological disorders. With respect to neurologic movement disorders, BoNT has been reported to be effective for the treatment of dystonia, bruxism, tremors, tics, myoclonus, restless legs syndrome, tardive dyskinesia, and a variety of symptoms associated with Parkinson's disease. More recently, research with BoNT has expanded beyond its use as a powerful muscle relaxant and a peripherally active drug to its potential central nervous system applications in the treatment of neurodegenerative disorders. Although BoNT is the most potent biologic toxin, when it is administered by knowledgeable and experienced clinicians, it is one of the safest therapeutic agents in clinical use. The primary aim of this article is to provide an update on recent advances in BoNT research with a focus on novel applications in the treatment of movement disorders. This comprehensive review of the literature provides a critical review of evidence-based clinical trials and highlights recent innovative pilot studies.

Botulinum Toxin-Associated Prolonged Remission of Idiopathic Cervical Dystonia

Prolonged remission of dystonia occurs rarely; however, well-documented cases are lacking. We report the clinical characteristics and course of four patients with botulinum toxin (BoNT)-associated prolonged remission of idiopathic cervical dystonia. Mean age at onset was 40 years. All had a relatively short duration of symptoms (mean 10.3 months), and with remission occurring after ≤ 3 treatments with BoNT. At last examination, the remission duration was 2-5 years. In the two cases that subsequently relapsed after 4-5 years, there was an altered phenomenology and worsened severity than at the onset. Recognizing this rare phenomenon has valuable clinical implications.

Functional and Idiopathic Cervical Dystonia in Two Family Members: A Challenging Diagnosis

Background:

Cervical dystonia (CD) often occurs in the same family.

Case report:

A 40-year-old woman presented with a longstanding history of CD and signs of inconsistency at history taking and neurological examination; her 65-year-old mother was diagnosed instead with idiopathic CD, which had begun 7 years after the onset of CD in her daughter.

Discussion:

Idiopathic and functional CD share common clinical and endophenotypic traits, making the differential diagnosis particularly challenging. A complete examination is warranted.

Olfaction as a Marker for Dystonia: Background, Current State and Directions

Dystonia is a heterogeneous group of hyperkinetic movement disorders. The unifying descriptor of dystonia is the motor manifestation, characterized by continuous or intermittent contractions of muscles that cause abnormal movements and postures. Additionally, there are psychiatric, cognitive, and sensory alterations that are possible or putative non-motor manifestations of dystonia. The pathophysiology of dystonia is incompletely understood. A better understanding of dystonia pathophysiology is highly relevant in the amelioration of significant disability associated with motor and non-motor manifestations of dystonia. Recently, diminished olfaction was found to be a potential non-motor manifestation that may worsen the situation of subjects with dystonia. Yet, this finding may also shed light into dystonia pathophysiology and yield novel treatment options. This article aims to provide background information on dystonia and the current understanding of its pathophysiology, including the key structures involved, namely, the basal ganglia, cerebellum, and sensorimotor cortex. Additionally, involvement of these structures in the chemical senses are reviewed to provide an overview on how olfactory (and gustatory) deficits may occur in dystonia. Finally, we describe the present findings on altered chemical senses in dystonia and discuss directions of research on olfactory dysfunction as a marker in dystonia.

Medical and Surgical Treatments for Dystonia

The dystonias are a large and heterogenous group of disorders characterized by excessive muscle contractions leading to abnormal postures and/or repetitive movements. Their clinical manifestations vary widely, and there are many potential causes. Despite the heterogeneity, helpful treatments are available for the vast majority of patients. Symptom-based therapies include oral medications, botulinum toxins, and surgical interventions. For some subtypes of dystonia, specific mechanism-based treatments are available. Advances in understanding the biological basis for many types of dystonia have led to numerous recent clinical trials, so additional treatments are likely to become available in the very near future.

Cannabinoids and dystonia: an issue yet to be defined

Dystonia is a movement disorder characterized by sustained or intermittent muscle contractions causing abnormal movements and postures. Besides motor manifestations, patients with dystonia also display non-motor signs and symptoms including psychiatric and sensory disturbances. Symptomatic treatment of motor signs in dystonia largely relies on intramuscular botulinum toxin injections and, in selected cases, on deep brain stimulation. Oral medications and physical therapy offer a few benefits only in a minority of patients. Cannabinoids have been shown to be a complementary treatment in several neurological disorders but their usefulness in dystonia have not been systematically assessed. Given recent policy changes in favor of cannabis use in clinical practice and the request for alternative treatments, it is important to understand how cannabinoids may impact people with dystonia. Reviewing the evidence so far available and our own experience, cannabinoids seem to be effective in single cases but further studies are required to improve our understanding on their role as complementary treatment in dystonia.