Treatment of dystonia

Movement disorders of the mouth: a review of the common phenomenologies

Movement disorders of the mouth encompass a spectrum of hyperactive movements involving the muscles of the orofacial complex. They are rare conditions and are described in the literature primarily in case reports originating from neurologists, psychiatrists, and the dental community. The focus of this review is to provide a phenomenological description of different oral motor disorders including oromandibular dystonia, orofacial dyskinesia and orolingual tremor, and to offer management strategies for optimal treatment based on the current literature. A literature search of full text studies using PubMed/Medline and Cochrane library combined with a manual search of the reference lists was conducted until June 2021. Results from this search included meta-analyses, systematic reviews, reviews, clinical studies, case series, and case reports published by neurologists, psychiatrists, dentists and oral and maxillofacial surgeons. Data garnered from these sources were used to provide an overview of most commonly encountered movement disorders of the mouth, aiding physicians in recognizing these rare conditions and in initiating appropriate therapy.

Supraspinal baclofen for the treatment of secondary generalized dystonia: A case series

PURPOSE

The aim of the study was to evaluate the use of a novel technique for baclofen delivery using an intrathecal catheter inserted through a lumbar laminotomy with the tip placed at the cisterna magna (supraspinal baclofen (SSB)) for the treatment of severe generalized secondary dystonia.

METHODS

A cohort study of six individuals (4M/2F, mean±SD = 15±4.86 years) with generalized dystonia unresponsive to oral medications were treated with SSB and followed clinically for 9 years. Intrathecal catheter tips were positioned under fluoroscopic guidance just above the level of the foramen magnum, at the cisterna magna.

RESULTS

Five of the 6 patients experienced sustained benefit with SSB; the group mean modified Fahn-Marsden scale scores decreased from 95 to 55 (t = 3.29, p = 0.02). One patient suffered complex pump pocket infection, and therefore underwent pump explantation.

CONCLUSION

Supraspinal baclofen may be an effective method for infusing baclofen into the ventricular system of the brain for treatment of secondary dystonia which is unresponsive to oral therapy.

Long-term effects of bilateral pallidal deep brain stimulation in dystonia: a follow-up between 8 and 16 years

Objective

Observational study to evaluate the long-term motor and non-motor effects of deep brain stimulation (DBS) of the globus pallidus internus (GPi) on medically refractory dystonia.

Background

Dystonia is a chronic disease affecting mainly young patients with a regular life expectancy and lifelong need for therapy. Pallidal DBS is an established treatment for severe isolated dystonia but long-term data are sparse.

Methods

We considered 36 consecutive patients with isolated generalized (n = 14) and cervical/segmental (n = 22) dystonia operated at Charité-University Hospital between 2000 and 2007 in a retrospective analysis for long-term outcome of pallidal DBS. In 19 of these patients, we could analyze dystonic symptoms and disability rated by the Burke–Fahn–Marsden Dystonia Rating scale (BFMDRS) at baseline, short-term (ST-FU, range 3–36 months) and long-term follow-up (LT-FU, range 93–197 months). Quality of life and mood were evaluated using the SF36 and Beck Depression Index (BDI) questionnaires.

Results

Patients reached an improvement in motor symptoms of 63.8 ± 5.7% (mean ± SE) at ST-FU and 67.9 ± 6.1% at LT-FU. Moreover, a significant and stable reduction in disability was shown following DBS (54.2 ± 9.4% at ST-FU and 53.8 ± 9.2% at LT-FU). BDI and SF36 had improved by 40% and 23%, respectively, at LT-FU (n = 14). Stimulation-induced adverse events included swallowing difficulties, dysarthria, and bradykinesia. Pulse generator (n = 3) and electrodes (n = 5) were revised in seven patients due to infection.

Conclusions

Pallidal DBS is a safe and efficacious long-term treatment for dystonia with sustained effects on motor impairment and disability, accompanied by a robust improvement in mood and quality of life.

Electronic supplementary material

The online version of this article (10.1007/s00415-020-09745-z) contains supplementary material, which is available to authorized users.

Disease Stabilization of DYT1-Positive Primary Generalized Dystonia With Deep Brain Stimulation of the Globus Pallidus Interna: A 15-Year Follow-up

BACKGROUND AND IMPORTANCE

Primary generalized dystonia (PGD) is a genetic form of dystonia that frequently displays pharmacological resistance and progresses quickly after onset. Deep brain stimulation (DBS) has been used successfully to treat refractory dystonia, specifically globus pallidus interna (GPi) DBS for DYT1-positive PGD patients. Long-term follow-up of the safety and efficacy falls short of the longevity seen in other diseases treated with DBS.

CASE PRESENTATION

A male patient presented for neurosurgical evaluation with scapular winging, hand contractures, and violent truncal spasms, which forced him to be bedridden. After failing conservative therapy, the 18-yr-old patient was implanted with bilateral GPi-DBS. DBS parameter adjustments were made primarily within the first 3 yr after implantation, with nominal changes thereafter. Initial settings were contact of 3 + 0−, amplitude of 4.9 V, frequency of 185 Hz, and pulse width of 270 μsec on the left and 3 + 0−, 2.8 V, 185 Hz, and 120 μsec on the right. Current settings are 3 + 2 + 1−, 5.2 V, 130 Hz, 330 μsec on the left and 3 + 0−, 3.5 V, 185 Hz, and 180 μsec on the right and have been relatively unchanged in the past 4 yr. Unified dystonia rating scale scores reveal a significant decrease in dystonic symptoms.

CONCLUSION

While prior reports have shown that GPi-DBS is effective for dystonia, this is the first with 15 yr of long-term follow-up showing disease stabilization, suggesting that stimulation is efficacious and can potentially prevent disease progression. This report reaffirms previous reports that recommend early surgical intervention before the onset of permanent musculoskeletal deficits.

Medical treatment of dystonia

Therapeutic strategies in dystonia have evolved considerably in the past few decades. Three major treatment modalities include oral medications, botulinum toxin injections and surgical therapies, particularly deep brain stimulation. Although there has been a tremendous interest in the later two modalities, there are relatively few recent reviews of oral treatment. We review the medical treatment of dystonia, focusing on three major neurotransmitter systems: cholinergic, GABAergic and dopaminergic. We also provide a practical guide to medication selection, therapeutic strategy and unmet needs.

[An analysis of treatment of the Russian group of patients in the international observational study «Factors influencing response to botulinum toxin type A in patients with idiopathic cervical dystonia»]

AIM

The analysis of the results of treatment of the Russian patient population in the frame of international, multicenter, non-interventional study of CD, the primary purpose of which was to determine the response rate to therapy with BTA at the peak of the effect: after one course of injections in settings of routine practice, as well as the results of application of modern definition for "response" to treatment with BTA.

MATERIAL AND METHODS

In Russia 60 patients with idiopathic CD were included. Patients were classified as «responders» according to the following 4 criteria: effect size (improvement by ≥ 25% assessed by TWSTRS); effect duration: ≥ 12 weeks interval between the BTA injection and the day when the patient reported a decrease of clinical effect, indicating the need for repeated treatment; good tolerability of treatment (no treatment-related serious adverse events (AEs) during the study period); patient-reported Clinical Global Improvement (CGI) score is +2 («significant improvement») or +3 («very significant improvement») at the visits 2 or 3.

RESULTS AND CONCLUSION

In the Russian population, patients with a ≥ 25% improvement by TWSTRS scale at visit 2 (peak effect) accounted for 88.3%. Most of patients (81.6%) and physicians (81.7%) evaluated the efficacy of therapy as a «significant improvement» or «very significant improvement» by CGI. The criterion of the effect duration was achieved in 50% of cases. The BTA therapy was well tolerated (no severe AEs related to treatment) in 98.3% of patients. Overall, 40% of all patients met all the criteria for response to BTA treatment. According to the analysis of the general population, a high degree of response was observed for the effect size (73.6%), tolerability (97.5%) and patient-reported global clinical improvement (69.8%). Subjective assessment of the duration of the effect was achieved in 49.3% of patients, with 28.6% of patients considered as responders. Most patients met three of the four criteria. The proposed multifactorial definition of «response» may be of practical use for routine practice.

Diagnosis and treatment of dystonia

The dystonias are a group of disorders characterized by excessive involuntary muscle contractions leading to abnormal postures and/or repetitive movements. A careful assessment of the clinical manifestations is helpful for identifying syndromic patterns that focus diagnostic testing on potential causes. If a cause is identified, specific etiology-based treatments may be available. In most cases, a specific cause cannot be identified, and treatments are based on symptoms. Treatment options include counseling, education, oral medications, botulinum toxin injections, and several surgical procedures. A substantial reduction in symptoms and improved quality of life is achieved in most patients by combining these options.

Deep brain stimulation

Deep brain stimulation (DBS) has provided remarkable therapeutic benefits for people with a variety of neurological disorders. Despite the uncertainty of the precise mechanisms underlying its efficacy, DBS is clinically effective in improving motor function of essential tremor, Parkinson's disease and primary dystonia and in relieving obsessive-compulsive disorder. Recently, this surgical technique has continued to expand to other numerous neurological diseases with encouraging results. This review highlighted the current and potential future clinical applications of DBS.

Clinical features and pharmacotherapy of childhood monoamine neurotransmitter disorders

Childhood neurotransmitter disorders are increasingly recognised as an expanding group of inherited neurometabolic syndromes. They are caused by disturbance in synthesis, metabolism, and homeostasis of the monoamine neurotransmitters, including the catecholamines (dopamine, norepinephrine, and epinephrine) and serotonin. Disturbances in monoamine neurotransmission will lead to neurological symptoms that often overlap with clinical features of other childhood neurological disorders (such as hypoxic ischaemic encephalopathy, cerebral palsy, other movement disorders, and paroxysmal conditions); consequently, neurotransmitter disorders are frequently misdiagnosed. The diagnosis of neurotransmitter disorders is made through detailed clinical assessment, analysis of cerebrospinal fluid neurotransmitters, and further supportive diagnostic investigations. Early and accurate diagnosis of neurotransmitter disorders is important, as many are amenable to therapeutic intervention. The principles of treatment for monoamine neurotransmitter disorders are mainly directly derived from understanding these metabolic pathways. In disorders characterized by enzyme deficiency, we aim to increase monoamine substrate availability, boost enzyme co-factor levels, reduce monoamine breakdown, and replace depleted levels of monoamines with pharmacological analogs as clinically indicated. Most monoamine neurotransmitter disorders lead to reduced levels of central dopamine and/or serotonin. Complete amelioration of motor symptoms is achievable in some disorders, such as Segawa's syndrome, and, in other conditions, significant improvement in quality of life can be attained with pharmacotherapy. In this review, we provide an overview of the clinical features and current treatment strategies for childhood monoamine neurotransmitter disorders.

The focal dystonias: current views and challenges for future research

The most common forms of dystonia are those that develop in adults and affect a relatively isolated region of the body. Although these adult-onset focal dystonias are most prevalent, knowledge of their etiologies and pathogenesis has lagged behind some of the rarer generalized dystonias, in which the identification of genetic defects has facilitated both basic and clinical research. This summary provides a brief review of the clinical manifestations of the adult-onset focal dystonias, focusing attention on less well understood clinical manifestations that need further study. It also provides a simple conceptual model for the similarities and differences among the different adult-onset focal dystonias as a rationale for lumping them together as a class of disorders while at the same time splitting them into subtypes. The concluding section outlines some of the most important research questions for the future. Answers to these questions are critical for advancing our understanding of this group of disorders and for developing novel therapeutics.

Visualization of the internal globus pallidus: sequence and orientation for deep brain stimulation using a standard installation protocol at 3.0 Tesla

BACKGROUND

Deep-brain stimulation (DBS) of the internal globus pallidus (GPi) has shown remarkable therapeutic benefits for treatment-resistant neurological disorders including dystonia and Parkinson's disease (PD). The success of the DBS is critically dependent on the reliable visualization of the GPi. The aim of the study was to evaluate promising 3.0 Tesla magnetic resonance imaging (MRI) methods for pre-stereotactic visualization of the GPi using a standard installation protocol.

METHODS

MRI at 3.0 T of nine healthy individuals and of one patient with PD was acquired (FLAIR, T1-MPRAGE, T2-SPACE, T2*-FLASH2D, susceptibility-weighted imaging mapping (SWI)). Image quality and visualization of the GPi for each sequence were assessed by two neuroradiologists independently using a 6-point scale. Axial, coronal, and sagittal planes of the T2*-FLASH2D images were compared. Inter-rater reliability, contrast-to-noise ratios (CNR) and signal-to-noise ratios (SNR) for the GPi were determined. For illustration, axial T2*-FLASH2D images were fused with a section schema of the Schaltenbrand-Wahren stereotactic atlas.

RESULTS

The GPi was best and reliably visualized in axial and to a lesser degree on coronal T2*-FLASH2D images. No major artifacts in the GPi were observed in any of the sequences. SWI offered a significantly higher CNR for the GPi compared to standard T2-weighted imaging using the standard parameters. The fusion of the axial T2*-FLASH2D images and the atlas projected the GPi clearly in the boundaries of the section schema.

CONCLUSIONS

Using a standard installation protocol at 3.0 T T2*-FLASH2D imaging (particularly axial view) provides optimal and reliable delineation of the GPi.

Factors influencing response to Botulinum toxin type A in patients with idiopathic cervical dystonia: results from an international observational study

OBJECTIVES

Real-life data on response to Botulinum toxin A (BoNT-A) in cervical dystonia (CD) are sparse. An expert group of neurologists was convened with the overall aim of developing a definition of treatment response, which could be applied in a non-interventional study of BoNT-A-treated subjects with CD.

DESIGN

International, multicentre, prospective, observational study of a single injection cycle of BoNT-A as part of normal clinical practice.

SETTING

38 centres across Australia, Belgium, Czech Republic, France, Germany, The Netherlands, Portugal, Russia and the UK.

PARTICIPANTS

404 adult subjects with idiopathic CD. Most subjects were women, aged 41-60 years and had previously received BoNT-A.

OUTCOME MEASURES

Patients were classified as responders if they met all the following four criteria: magnitude of effect (≥25% improvement Toronto Western Spasmodic Torticollis Rating Scale), duration of effect (≥12-week interval between the BoNT-A injection day and subject-reported waning of treatment effect), tolerability (absence of severe related adverse event) and subject's positive Clinical Global Improvement (CGI).

RESULTS

High rates of response were observed for magnitude of effect (73.6%), tolerability (97.5%) and subject's clinical global improvement (69.8%). The subjective duration of effect criterion was achieved by 49.3% of subjects; 28.6% of subjects achieved the responder definition. Factors most strongly associated with response were age (<40 years; OR 3.9, p<0.05) and absence of baseline head tremor (OR 1.5; not significant).

CONCLUSIONS

Three of four criteria were met by most patients. The proposed multidimensional definition of response appears to be practical for routine practice. Unrealistically high patient expectation and subjectivity may influence the perception of a quick waning of effect, but highlights that this aspect may be a hurdle to response in some patients. CLINICAL REGISTRATION NUMBER: (NCT00833196; ClinicalTrials.gov).

In vivo neurochemistry of primary focal hand dystonia: a magnetic resonance spectroscopic neurometabolite profiling study at 3T

The neurochemical basis of dystonia is unknown. The purpose of this study was to assess the differences of the inhibitory neurotransmitter, gamma amino butyric acid (GABA), in the sensorimotor cortex and the basal ganglia using magnetic resonance spectroscopy with optimized GABA sensitivity. Twenty-two patients with focal hand dystonia and 22 healthy controls were studied. No significant differences in GABA were observed between the groups in either the sensorimotor cortex or in the basal ganglia.

Association of botulinum neurotoxin serotype A light chain with plasma membrane-bound SNAP-25

The Clostridium botulinum neurotoxins (BoNTs) cleave SNARE proteins, which inhibit binding and thus fusion of neurotransmitter vesicles to the plasma membrane of peripheral neurons. BoNTs comprise an N-terminal light chain (LC) and C-terminal heavy chain, which are linked by a disulfide bond. There are seven serotypes (A-G) of BoNTs based upon immunological neutralization. Although the binding and entry of BoNT/A into neurons has been subjected to considerable investigation, the intracellular events that allow BoNT/A to efficiently cleave SNAP-25 within neurons is less well understood. Earlier studies showed that intracellular LC/A bound to the plasma membrane of neurons. In this study, intracellular LC/A is shown to directly bind SNAP-25 on the plasma membrane. Solid phase binding showed that the N-terminal residues of LC/A bound residues 80-110 of SNAP-25, which was also observed in cultured neurons. Association of the N-terminal 8 amino acids of LC/A and residues 80-110 of SNAP-25 also enhanced substrate cleavage. These findings explain how LC/A associates with SNAP-25 on the plasma membrane and provide a basis for LC/A cleavage of SNAP-25 within the SNARE complex.

Stimulation of the globus pallidus internus in a patient with DYT1-positive primary generalized dystonia: a 10-year follow-up

The authors report the case of DYT1-positive primary generalized dystonia refractory to medical management that was successfully treated with continuous deep brain stimulation of the internal segment of the globus pallidus. Prior studies have shown that neuromusculoskeletal deficits can remain permanent if early surgical intervention is not undertaken. The authors report prolonged efficacy and safety over a 10-year period in a 28-year-old man.

Treatment strategies for dystonia

IMPORTANCE OF THE FIELD

Dystonia is a neurological syndrome characterized by involuntary twisting movements and unnatural postures. It has many different manifestations and causes, and many different treatment options are available. These options include physical and occupational therapy, oral medications, intramuscular injection of botulinum toxins, and neurosurgical interventions.

AREAS COVERED IN THIS REVIEW

In this review, we first summarize the treatment options available, then we provide suggestions from our own experience for how these can be applied in different types of dystonia. In preparing this review article, an extensive literature search was undertaken using PubMed. Only selected references from 1970 to 2008 are cited.

WHAT THE READER WILL GAIN

This review is intended to provide the clinician with a practical guide to the treatment of dystonia.

TAKE HOME MESSAGE

Treatment of dystonia begins with proper diagnosis and classification, followed by an appropriate search for underlying etiology, and an assessment of the functional impairment associated with the dystonia. The therapeutic approach, which is usually limited to symptomatic therapy, must then be tailored to the individual needs of the patient.

New clinical and research trends in lower extremity management for ambulatory children with cerebral palsy

Cerebral palsy (CP) is the most prevalent physical disability in childhood and includes a group of disorders with varying manifestations. This article focuses on current and future intervention strategies for improving mobility and participation during the lifespan for ambulatory children with CP. The provision and integration of physical therapy and medical and orthopedic surgery management focused primarily on the lower extremities are discussed here. Some of the newer trends are more intense and task-related exercise strategies, greater precision in tone identification and management, and a shift towards musculoskeletal surgery that focuses more on promoting dynamic bony alignment and less on releasing or lengthening tendons. Advances in basic and clinical science and technology development are changing existing paradigms and offering renewed hope for improved functioning for children with CP who face a lifelong disability with unique challenges at each stage in life.