Deep brain stimulation for dystonia

Diffusion tensor imaging in pediatric patients with dystonia

BACKGROUND

Childhood-onset dystonia is often progressive and severely impairs a child´s life. The pathophysiology is very heterogeneous and treatment responses vary in patients with dystonia. Factors influencing treatment effects remain to be elucidated. We hypothesize that differences in brain connectivity and fiber coherence contribute to the heterogeneity in treatment response among pediatric patients with inherited and acquired dystonia.

METHODS

Twenty patients with childhood-onset dystonia were retrospectively recruited including twelve patients with inherited or idiopathic, and eight patients with acquired dystonia (mean age 10 years; 8 female/12 male). Fiber density between the internal part of the globus pallidus and selective target regions, as well as the diffusion measures of fractional anisotropy (FA) and mean diffusivity (MD) were analyzed and compared between different etiologies.

RESULTS

Patients with acquired dystonia presented higher fiber density to the premotor cortex and putamen and lower FA values in the thalamus compared to patients with inherited/idiopathic dystonia. MD in the premotor cortex was higher in patients with acquired dystonia, while it was lower in the thalamus.

CONCLUSION

Diffusion MRI reveals microstructural and network alterations in patients with dystonia of different etiologies.

Towards an optimised deep brain stimulation using a large-scale computational network and realistic volume conductor model

Objective. Constructing a theoretical framework to improve deep brain stimulation (DBS) based on the neuronal spatiotemporal patterns of the stimulation-affected areas constitutes a primary target.Approach. We develop a large-scale biophysical network, paired with a realistic volume conductor model, to estimate theoretically efficacious stimulation protocols. Based on previously published anatomically defined structural connectivity, a biophysical basal ganglia-thalamo-cortical neuronal network is constructed using Hodgkin-Huxley dynamics. We define a new biomarker describing the thalamic spatiotemporal activity as a ratio of spiking vs. burst firing. The per cent activation of the different pathways is adapted in the simulation to minimise the differences of the biomarker with respect to its value under healthy conditions.Main results.This neuronal network reproduces spatiotemporal patterns that emerge in Parkinson's disease. Simulations of the fibre per cent activation for the defined biomarker propose desensitisation of pallido-thalamic synaptic efficacy, induced by high-frequency signals, as one possible crucial mechanism for DBS action. Based on this activation, we define both an optimal electrode position and stimulation protocol using pathway activation modelling.Significance. A key advantage of this research is that it combines different approaches, i.e. the spatiotemporal pattern with the electric field and axonal response modelling, to compute the optimal DBS protocol. By correlating the inherent network dynamics with the activation of white matter fibres, we obtain new insights into the DBS therapeutic action.

Clinical and Psychosocial Factors Considered When Deciding Whether to Offer Deep Brain Stimulation for Childhood Dystonia

INTRODUCTION

Childhood dystonia is often nonresponsive to medications, and refractory cases are increasingly being treated with deep brain stimulation (DBS). However, many have noted that there is little consensus about when DBS should be offered, and there has been little examination of clinicians' decision-making process when determining whether to offer DBS for childhood dystonia.

OBJECTIVES

This study aimed to identify and examine the factors considered by pediatric movement disorder specialists before offering DBS.

MATERIALS AND METHODS

Semistructured interviews (N = 29) with pediatric dystonia clinicians were conducted, transcribed, and coded. Using thematic content analysis, nine central themes were identified when clinicians were asked about key factors, clinical factors, and psychosocial factors considered before offering pediatric DBS.

RESULTS

Clinicians identified nine main factors. Five of these were classified primarily as clinical factors: early intervention and younger age (raised by 86% of respondents), disease progression and symptom severity (83%), etiology and genetic status (79%), clinicians' perceived risks and benefits of DBS for the patient (79%), and exhaustion of other treatment options (55%). The remaining four were classified primarily as psychosocial factors: social and family support (raised by 97% of respondents), patient and caregiver expectations about outcomes and understanding of DBS treatment (90%), impact of dystonia on quality of life (69%), and financial resources and access to care (31%).

CONCLUSIONS

Candidacy determinations, in this context, are complicated by an interrelation of clinical and psychosocial factors that contribute to the decision. There is potential for bias when considering family support and quality of life. Uncertainty of outcomes related to the etiology of dystonia makes candidacy judgments challenging. More systematic examination of the characteristics and criteria used to identify pediatric patients with dystonia who can significantly benefit from DBS is necessary to develop clear guidelines and promote the well-being of these children.

Electrophysiological insights into deep brain stimulation of the network disorder dystonia

Deep brain stimulation (DBS), a treatment for modulating the abnormal central neuronal circuitry, has become the standard of care nowadays and is sometimes the only option to reduce symptoms of movement disorders such as dystonia. However, on the one hand, there are still open questions regarding the pathomechanisms of dystonia and, on the other hand, the mechanisms of DBS on neuronal circuitry. That lack of knowledge limits the therapeutic effect and makes it hard to predict the outcome of DBS for individual dystonia patients. Finding electrophysiological biomarkers seems to be a promising option to enable adapted individualised DBS treatment. However, biomarker search studies cannot be conducted on patients on a large scale and experimental approaches with animal models of dystonia are needed. In this review, physiological findings of deep brain stimulation studies in humans and animal models of dystonia are summarised and the current pathophysiological concepts of dystonia are discussed.

Essential Tremor - Deep Brain Stimulation vs. Focused Ultrasound

INTRODUCTION

Essential Tremor (ET) is one of the most common tremor syndromes typically presented as action tremor, affecting mainly the upper limbs. In at least 30-50% of patients, tremor interferes with quality of life, does not respond to first-line therapies and/or intolerable adverse effects may occur. Therefore, surgery may be considered.

AREAS COVERED

In this review, the authors discuss and compare unilateral ventral intermedius nucleus deep brain stimulation (VIM DBS) and bilateral DBS with Magnetic Resonance-guided Focused Ultrasound (MRgFUS) thalamotomy, which comprises focused acoustic energy generating ablation under real-time MRI guidance. Discussion includes their impact on tremor reduction and their potential complications. Finally, the authors provide their expert opinion.

EXPERT OPINION

DBS is adjustable, potentially reversible and allows bilateral treatments; however, it is invasive requires hardware implantation, and has higher surgical risks. Instead, MRgFUS is less invasive, less expensive, and requires no hardware maintenance. Beyond these technical differences, the decision should also involve the patient, family, and caregivers.

A comparison of how deep brain stimulation in two targets with anti-compulsive efficacy modulates brain activity using fMRI in awake rats

Deep brain stimulation (DBS) is an established neuromodulatory intervention against otherwise treatment-refractory obsessive-compulsive disorder (OCD). Several DBS targets, all of which are part of brain networks connecting basal ganglia and prefrontal cortex, alleviate OCD symptoms. Stimulation of these targets is thought to unfold its therapeutic effect by modulation of network activity through internal capsule (IC) connections. Research into DBS-induced network changes and the nature of IC-related effects of DBS in OCD is needed to further improve DBS. Here, we studied the effects of DBS at the ventral medial striatum (VMS) and IC on blood-oxygen level dependent (BOLD) responses in awake rats using functional magnetic resonance imaging (fMRI). BOLD-signal intensity was measured in five regions of interest (ROIs): medial and orbital prefrontal cortex, nucleus accumbens (NAc), IC area, and mediodorsal thalamus. In previous rodent studies, stimulation at both target locations resulted in a reduction of OCD-like behavior and activation of prefrontal cortical areas. Therefore, we hypothesized that stimulation at both targets would result in partially overlapping BOLD responses. Both differential and overlapping activity between VMS and IC stimulation was found. Stimulating the caudal part of the IC resulted in activation around the electrode, while stimulating the rostral part of the IC resulted in increased cross-correlations between the IC area, orbitofrontal cortex, and NAc. Stimulation of the dorsal part of the VMS resulted in increased activity in the IC area, suggesting this area is activated during both VMS and IC stimulation. This activation is also indicative of VMS-DBS impacting corticofugal fibers running through the medial caudate into the anterior IC, and both VMS and IC DBS might act on these fibers to induce OCD-reducing effects. These results show that rodent fMRI with simultaneous electrode stimulation is a promising approach to study the neural mechanisms of DBS. Comparing the effects of DBS in different target areas has the potential to improve our understanding of the neuromodulatory changes that take place across various networks and connections in the brain. Performing this research in animal disease models will lead to translational insights in the mechanisms underlying DBS, and can aid improvement and optimization of DBS in patient populations.

Motor deficit and lack of overt dystonia in Dlx conditional Dyt1 knockout mice

DYT1 or DYT-TOR1A dystonia is early-onset generalized dystonia caused by a trinucleotide deletion of GAG in the TOR1A or DYT1 gene leads to the loss of a glutamic acid residue in the resulting torsinA protein. A mouse model with overt dystonia is of unique importance to better understand the DYT1 pathophysiology and evaluate preclinical drug efficacy. DYT1 dystonia is likely a network disorder involving multiple brain regions, particularly the basal ganglia. Tor1a conditional knockout in the striatum or cerebral cortex leads to motor deficits, suggesting the importance of corticostriatal connection in the pathogenesis of dystonia. Indeed, corticostriatal long-term depression impairment has been demonstrated in multiple targeted DYT1 mouse models. Pappas and colleagues developed a conditional knockout line (Dlx-CKO) that inactivated Tor1a in the forebrain and surprisingly displayed overt dystonia. We set out to validate whether conditional knockout affecting both cortex and striatum would lead to overt dystonia and whether machine learning-based video behavioral analysis could be used to facilitate high throughput preclinical drug screening. We generated Dlx-CKO mice and found no overt dystonia or motor deficits at 4 months. At 8 months, retesting revealed motor deficits in rotarod, beam walking, grip strength, and hyperactivity in the open field; however, no overt dystonia was visually discernible or through the machine learning-based video analysis. Consistent with other targeted DYT1 mouse models, we observed age-dependent deficits in the beam walking test, which is likely a better motor behavioral test for preclinical drug testing but more labor-intensive when overt dystonia is absent.

Neuromodulation in Dystonia - Harnessing the Network

Adult-onset isolated focal dystonia (AOIFD) is a network disorder characterised by abnormalities of sensory processing and motor control. These network abnormalities give rise to both the phenomenology of dystonia and the epiphenomena of altered plasticity and loss of intracortical inhibition. Existing modalities of deep brain stimulation effectively modulate parts of this network but are limited both in terms of targets and invasiveness. Novel approaches using a variety of non-invasive neuromodulation techniques including transcranial stimulation and peripheral stimulation present an interesting alternative approach and may, in conjunction with rehabilitative strategies, have a role in tailored therapies targeting the underlying network abnormality behind AOIFD.

Synaptic Dysfunction in Dystonia: Update From Experimental Models

Dystonia, the third most common movement disorder, refers to a heterogeneous group of neurological diseases characterized by involuntary, sustained or intermittent muscle contractions resulting in repetitive twisting movements and abnormal postures. In the last few years, several studies on animal models helped expand our knowledge of the molecular mechanisms underlying dystonia. These findings have reinforced the notion that the synaptic alterations found mainly in the basal ganglia and cerebellum, including the abnormal neurotransmitters signalling, receptor trafficking and synaptic plasticity, are a common hallmark of different forms of dystonia. In this review, we focus on the major contribution provided by rodent models of DYT-TOR1A, DYT-THAP1, DYT-GNAL, DYT/ PARK-GCH1, DYT/PARK-TH and DYT-SGCE dystonia, which reveal that an abnormal motor network and synaptic dysfunction represent key elements in the pathophysiology of dystonia.

Neurophysiological Basis of Deep Brain Stimulation and Botulinum Neurotoxin Injection for Treating Oromandibular Dystonia

Oromandibular dystonia (OMD) induces severe motor impairments, such as masticatory disturbances, dysphagia, and dysarthria, resulting in a serious decline in quality of life. Non-invasive brain-imaging techniques such as electroencephalography (EEG) and magnetoencephalography (MEG) are powerful approaches that can elucidate human cortical activity with high temporal resolution. Previous studies with EEG and MEG have revealed that movements in the stomatognathic system are regulated by the bilateral central cortex. Recently, in addition to the standard therapy of botulinum neurotoxin (BoNT) injection into the affected muscles, bilateral deep brain stimulation (DBS) has been applied for the treatment of OMD. However, some patients' OMD symptoms do not improve sufficiently after DBS, and they require additional BoNT therapy. In this review, we provide an overview of the unique central spatiotemporal processing mechanisms in these regions in the bilateral cortex using EEG and MEG, as they relate to the sensorimotor functions of the stomatognathic system. Increased knowledge regarding the neurophysiological underpinnings of the stomatognathic system will improve our understanding of OMD and other movement disorders, as well as aid the development of potential novel approaches such as combination treatment with BoNT injection and DBS or non-invasive cortical current stimulation therapies.

Utility of Postoperative Imaging Software for Deep Brain Stimulation Targeting in Patients with Movement Disorders

OBJECTIVE

The objective of this study was to evaluate the accuracy of the SureTune3 postoperative imaging software in determining the location of a deep brain stimulation (DBS) electrode based on clinical outcomes and the adverse effects (AEs) observed.

METHODS

Twenty-six consecutive patients with Parkinson disease (n = 17), essential tremor (n = 8), and dystonia (n = 1) who underwent bilateral DBS surgery (52 electrodes) were included in this study. Presurgical assessments were performed in all patients prior to surgery and at 3 and 6 months after surgery, using quality-of-life and clinical scales in each case. The SureTune3 software was used to evaluate the anatomical positioning of the DBS electrodes.

RESULTS

Following DBS surgery, motor and quality-of-life improvement was observed in all patients. Different AEs were detected in 12 patients, in 10 of whom (83.3%) SureTune3 related the symptoms to the positioning of an electrode. A clinical association was observed with SureTune3 for 48 of 52 (92.3%) electrodes, whereas no association was found between the AEs or clinical outcomes and the SureTune3 reconstructions for 4 of 52 electrodes (7.7%) from 4 different patients. In 2 patients, the contact chosen was modified based on the SureTune3 data, and in 2 cases, the software helped determine that second electrode replacement surgery was necessary.

CONCLUSIONS

The anatomical position of electrodes analyzed with SureTune3 software was strongly correlated with both the AEs and clinical outcomes. Thus, SureTune3 may be useful in clinical practice, and it could help improve stimulation parameters and influence decisions to undertake electrode replacement surgery.

Deep brain stimulation for movement disorder treatment: exploring frequency-dependent efficacy in a computational network model

A large-scale computational model of the basal ganglia network and thalamus is proposed to describe movement disorders and treatment effects of deep brain stimulation (DBS). The model of this complex network considers three areas of the basal ganglia region: the subthalamic nucleus (STN) as target area of DBS, the globus pallidus, both pars externa and pars interna (GPe-GPi), and the thalamus. Parkinsonian conditions are simulated by assuming reduced dopaminergic input and corresponding pronounced inhibitory or disinhibited projections to GPe and GPi. Macroscopic quantities are derived which correlate closely to thalamic responses and hence motor programme fidelity. It can be demonstrated that depending on different levels of striatal projections to the GPe and GPi, the dynamics of these macroscopic quantities (synchronisation index, mean synaptic activity and response efficacy) switch from normal to Parkinsonian conditions. Simulating DBS of the STN affects the dynamics of the entire network, increasing the thalamic activity to levels close to normal, while differing from both normal and Parkinsonian dynamics. Using the mentioned macroscopic quantities, the model proposes optimal DBS frequency ranges above 130 Hz.

Pallidal neuron activity determines responsiveness to deep brain stimulation in cervical dystonia

OBJECTIVE

In patients with cervical dystonia we sought for the differences in neuronal behavior of pallidal regions where deep brain stimulation resulted in favorable therapeutic response compared to those where the response was absent.

METHODS

We compared single-unit activity of 564 neurons recorded from deep brain stimulation sensitive and non-sensitive regions in 17 cervical dystonia patients.

RESULTS

Globus pallidus internus regions responsive to the deep brain stimulation had lower firing rates and bursting compared to non-responsive areas. The differences were robust in locations where neuronal responses correlated with neck movements. Per the effects of deep brain stimulation, the pallidal regions were classified in weak, intermediate, and excellent responsive. Pallidal regions with weak response to deep brain stimulation had fewer burst neurons and higher firing rate compared to neurons in areas with excellent response. The burst index was significantly decreased in excellent response regions. There was a significant decrease in the alpha band oscillation score but a substantial increase in the gamma band in excellent response neurons.

CONCLUSION

The pallidal region that would be responsive to deep brain stimulation has distinct physiology compared to the non-responsive region.

SIGNIFICANCE

These results provide novel insights into globus pallidus interna neurons' physiology in cervical dystonia.

Globus Pallidus Internus Deep Brain Stimulation for Dystonic Opisthotonus in Adult-Onset Dystonia: A Personalized Approach

Introduction

Dystonic opisthotonus is defined as a backward arching of the neck and trunk, which ranges in severity from mild backward jerks to life-threatening prolonged severe muscular spasms. It can be associated with generalized dystonic syndromes or, rarely, present as a form of axial truncal dystonia. The etiologies vary from idiopathic, genetic, tardive, hereditary-degenerative, or associated with parkinsonism. We report clinical cases of dystonic opisthotonus associated with adult-onset dystonic syndromes, that benefitted from globus pallidus internus (GPi) deep brain stimulation (DBS).

Methods

Clinical data from patients with dystonic syndromes who underwent comprehensive medical review, multidisciplinary assessment, and tailored medical and neurosurgical managements were prospectively analyzed. Quantification of dystonia severity pre- and postoperatively was performed using the Burke-Fahn-Marsden Dystonia Rating Scale and quantification of overall pain severity was performed using the Visual Analog Scale.

Results

Three male patients, with age of onset of the dystonic symptoms ranging from 32 to 51 years old, were included. Tardive dystonia, adult-onset dystonia-parkinsonism and adult-onset idiopathic axial dystonia were the etiologies identified. Clinical investigation and management were tailored according to the complexity of the individual presentations. Although they shared common clinical features of adult-onset dystonia, disabling dystonic opisthotonus, refractory to medical management, was the main indication for GPi-DBS in all patients presented. The severity of axial dystonia ranged from disturbance of daily function to life-threatening truncal distortion. All three patients underwent bilateral GPi DBS at a mean age of 52 years (range 48–55 years), after mean duration of symptoms prior to DBS of 10.7 years (range 4–16 years). All patients showed a rapid and sustained clinical improvement of their symptoms, notably of the dystonic opisthotonos, at postoperative follow-up ranging from 20 to 175 months. In some, the ability to resume activities of daily living and reintegration into the society was remarkable.

Conclusion

Adult-onset dystonic syndromes predominantly presenting with dystonic opisthotonus are relatively rare. The specific nature of dystonic opisthotonus remains a treatment challenge, and thorough investigation of this highly disabling condition with varying etiologies is often necessary. Although patients may be refractory to medical management and botulinum toxin injection, Globus pallidus stimulation timed and tailored provided symptomatic control in this cohort and may be considered in other carefully selected cases.

A practical guide to troubleshooting pallidal deep brain stimulation issues in patients with dystonia

High frequency deep brain stimulation (DBS) of the internal portion of the globus pallidus has, in the last two decades, become a mainstream therapy for the management of medically-refractory dystonia syndromes. Such increasing uptake places an onus on movement disorder physicians to become familiar with this treatment modality, in particular optimal patient selection for the procedure and how to troubleshoot problems relating to sub-optimal efficacy and therapy-related side effects. Deep brain stimulation for dystonic conditions presents some unique challenges. For example, the frequent lack of immediate change in clinical status following stimulation alterations means that programming often relies on personal experience and local practice rather than real-time indicators of efficacy. Further, dystonia is a highly heterogeneous disorder, making the development of unifying guidelines and programming algorithms for DBS in this population difficult. Consequently, physicians may feel less confident in managing DBS for dystonia as compared to other indications e.g. Parkinson's disease. In this review, we integrate our years of personal experience of the programming of DBS systems for dystonia with a critical appraisal of the literature to produce a practical guide for troubleshooting common issues encountered in patients with dystonia treated with DBS, in the hope of improving the care for these patients.

Efficacy and safety of general anesthesia deep brain stimulation for dystonia: an individual patient data meta-analysis of 341 cases

OBJECTIVE

The efficacy and safety of deep brain stimulation (DBS) under general anesthesia for the treatment of dystonia have not yet been confirmed with high level of evidence. This meta-analysis with pooled individual patient data aims to assess the clinical outcomes and identify the potential prognostic factors of dystonia patients who underwent general anesthesia DBS.

METHODS

We searched PubMed, Web of Science, and Embase for articles describing patients with dystonia who underwent asleep DBS and had individual Burke-Fahn-Marsden Dystonia Rating Scale (BFMDRS) scores. The relative improvement in BFMDRS scores was considered the primary outcome. Pearson correlation analyses and multivariate linear regression analysis were conducted to explore the prognostic factors.

RESULTS

A total of 34 studies involving 341 patients were included. The mean postoperative improvement in BFMDRS-M (BFMDRS movement subscale) and BFMDRS-D (BFMDRS disability subscale) scores were 58.6±36.2% and 48.5±38.7% at the last follow-up visit, respectively, with a mean follow-up time of 22.4±27.6 months. Age at surgery and disease duration showed a negative correlation with the percent improvement of BFMDRS-M (%) at the last visit (r=-0.134, P=0.013; r=-0.165, P=0.006). In the stepwise multivariate regression, only disease duration remained a relevant factor. Additionally, the adverse events were acceptable.

CONCLUSION

General anesthesia DBS is a safe, effective, and feasible option for dystonia patients in the long term. Shorter disease duration predicts better clinical outcomes.

Bilateral Pallidal Stimulation in a Family With Myoclonus Dystonia Syndrome Due to a Mutation in the Sarcoglycan Gene

OBJECTIVES

The study aimed to present a family with myoclonus dystonia (M-D) syndrome due to a mutation in the epsilon sarcoglycan gene (SGCE). Three members of the family suffered from treatment-refractory severe myoclonic jerks of the neck, trunk, and upper extremities. The mild dystonic symptoms recognized as cervical dystonia or truncal dystonia affected all individuals. The efficacy of pharmacotherapy, including anticholinergic, dopaminergic, and serotoninergic drugs, has failed. One individual developed an alcohol dependency and suffered from alcoholic epilepsy.

MATERIALS AND METHODS

The patients were referred for stereotactic surgery. All individuals underwent bilateral implantation of deep brain stimulation (DBS) leads into the posteroventrolateral segment of the globus pallidus internus (GPi). Surgeries were uneventful. The formal preoperative objective assessment included the Unified Myoclonus Rating Scale (UMRS) and the Burke-Fahn-Marsden Dystonia Rating Scale (BFMDRS). The postoperative UMRS and BFMDRS assessments were done only under continuous stimulation at 3, 6, and 12 months after the surgery and at the last available follow-up ranging from 6 to 15 months (mean, 10 months follow-up).

RESULTS

At the last follow-up visit, the rest and action parts of UMRS were improved by 93.3% and 88.2%, respectively, when compared to the baseline scores. The motor and disability scales of BFMDRS were improved by 77% and 43% at the last follow-up visit compared to the baseline BFMDRS scores. There were no hardware or stimulation-induced complications over the follow-up period. Positive social adjustment allowed two patients to regain jobs and one patient continued his education and hobbies.

CONCLUSION

Our experience gathered in three individuals in the family with a mutation in SGCE indicates that bilateral GPi DBS can be an effective and safe treatment for disabling pharmacological resistant, intractable M-D syndrome.

Pallidal Deep Brain Stimulation for Monogenic Dystonia: The Effect of Gene on Outcome

Globus pallidus internus deep brain stimulation (GPi DBS) is the most effective intervention for medically refractory segmental and generalized dystonia in both children and adults. Predictive factors for the degree of improvement after GPi DBS include shorter disease duration and dystonia subtype with idiopathic isolated dystonia usually responding better than acquired combined dystonias. Other factors contributing to variability in outcome may include body distribution, pattern of dystonia and DBS related factors such as lead placement and stimulation parameters. The responsiveness to DBS appears to vary between different monogenic forms of dystonia, with some improving more than others. The first observation in this regard was reports of superior DBS outcomes in DYT-TOR1A (DYT1) dystonia, although other studies have found no difference. Recently a subgroup with young onset DYT-TOR1A, more rapid progression and secondary worsening after effective GPi DBS, has been described. Myoclonus dystonia due to DYT-SCGE (DYT11) usually responds well to GPi DBS. Good outcomes following GPi DBS have also been documented in X-linked dystonia Parkinsonism (DYT3). In contrast, poorer, more variable DBS outcomes have been reported in DYT-THAP1 (DYT6) including a recent larger series. The outcome of GPi DBS in other monogenic isolated and combined dystonias including DYT-GNAL (DYT25), DYT-KMT2B (DYT28), DYT-ATP1A3 (DYT12), and DYT-ANO3 (DYT24) have been reported with varying results in smaller numbers of patients. In this article the available evidence for long term GPi DBS outcome between different genetic dystonias is reviewed to reappraise popular perceptions of expected outcomes and revisit whether genetic diagnosis may assist in predicting DBS outcome.

Deep brain stimulation treatment in dystonia: a bibliometric analysis

BACKGROUND

Dystonia is a heterogeneous disorder that, when refractory to medical treatment, may have a favorable response to deep brain stimulation (DBS). A practical way to have an overview of a research domain is through a bibliometric analysis, as it makes it more accessible for researchers and others outside the field to have an idea of its directions and needs.

OBJECTIVE

To analyze the 100 most cited articles in the use of DBS for dystonia treatment in the last 30 years.

METHODS

The research protocol was performed in June 2019 in Elsevier's Scopus database, by retrieving the most cited articles regarding DBS in dystonia. We analyzed authors, year of publication, country, affiliation, and targets of DBS.

RESULTS

Articles are mainly published in Movement Disorders (19%), Journal of Neurosurgery (9%), and Neurology (9%). European countries offer significant contributions (57% of our sample). France (192.5 citations/paper) and Germany (144.1 citations/paper) have the highest citation rates of all countries. The United States contributes with 31% of the articles, with 129.8 citations/paper. The publications are focused on General outcomes (46%), followed by Long-term outcomes (12.5%), and Complications (11%), and the leading type of dystonia researched is idiopathic or inherited, isolated, segmental or generalized dystonia, with 27% of articles and 204.3 citations/paper.

CONCLUSIONS

DBS in dystonia research is mainly published in a handful of scientific journals and focused on the outcomes of the surgery in idiopathic or inherited, isolated, segmental or generalized dystonia, and with globus pallidus internus as the main DBS target.

Comparison between deep brain stimulation and magnetic resonance-guided focused ultrasound in the treatment of essential tremor: a systematic review and pooled analysis of functional outcomes

The current gold standard surgical treatment for medication-resistant essential tremor (ET) is deep brain stimulation (DBS). However, recent advances in technologies have led to the development of incisionless techniques, such as magnetic resonance-guided focused ultrasound (MRgFUS) thalamotomy. The authors perform a systematic review according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses statement to compare unilateral MRgFUS thalamotomy to unilateral and bilateral DBS in the treatment of ET in terms of tremor severity and quality of life improvement. PubMed, Cochrane Database of Systematic Reviews, Cochrane Central Register of Controlled Trials and SCOPUS databases were searched. 45 eligible articles, published between 1990 and 2019, were retrieved. 1202 patients were treated with DBS and 477 were treated with MRgFUS thalamotomy. Postoperative tremor improvement was greater following DBS than MRgFUS thalamotomy (p<0.001). A subgroup analysis was carried out stratifying by treatment laterality: bilateral DBS was significantly superior to both MRgFUS and unilateral DBS (p<0.001), but no significant difference was recorded between MRgFUS and unilateral DBS (p<0.198). Postoperative quality of life improvement was significantly greater following MRgFUS thalamotomy than DBS (p<0.001). Complications were differently distributed among the two groups (p<0.001). Persistent complications were significantly more common in the MRgFUS group (p=0.042). While bilateral DBS proves superior to unilateral MRgFUS thalamotomy in the treatment of ET, a subgroup analysis suggests that treatment laterality is the most significant determinant of tremor improvement, thus highlighting the importance of future investigations on bilateral staged MRgFUS thalamotomy.

Subthalamic Nucleus Deep Brain Stimulation in Post-Infarct Dystonia

Dystonia secondary to cerebral infarcts presents months to years after the initial insult, is usually unilateral and causes significant morbidity. Deep brain stimulation (DBS) of the globus pallidus internus (GPi) is established as the most frequent target in the management of the dystonic symptoms. We report our experience with subthalamic nucleus (STN) DBS in 3 patients with post-infarct dystonia, in whom GPi DBS was not confidently possible due to the presence of striatal infarcts. Two patients had unilateral STN DBS implantation, whereas the third patient had bilateral STN DBS implantation for bilateral dystonic symptoms. Prospectively collected preoperative and postoperative functional assessment data including imaging, medication and neuropsychology evaluations were analyzed with regard to symptom improvement. Median follow-up period was 38.3 months (range 26–43 months). All patients had clinically valuable improvements in dystonic symptoms and pain control despite variable improvements in the Burke-Fahn-Marsden dystonia rating scores. In our series, we have demonstrated that STN DBS could be an alternative in the management of post-infarct dystonia in patients with abnormal striatal anatomy which precludes GPi DBS. A multidisciplinary team-based approach is essential for patient selection and management.

Image analysis of the intracranial lead bending phenomenon during deep brain stimulation

Background

An accurate and precise surgical procedure is crucial for patient safety and treatment efficacy of deep brain stimulation (DBS).

Objectives

To investigate the characteristics of intracranial lead bending phenomenon after DBS, and to suggest the methods to avoid bending-related complications.

Methods

A retrospective review of brain computed tomography scans after DBS was performed. Using 3-dimensional reconstruction, the maximal distance between the planned trajectory and actual lead location was measured. When the distance exceeded the lead body diameter, the lead was considered bent. The distance between the bending point and planned trajectory, and the relative direction between the bending point and lead securing site were analyzed. Changes over time in the range of lead bending and depth were analyzed when possible.

Results

A total of 190 implanted leads in 102 patients were analyzed; 104 leads (54.7%) were bent. The average deviation of bent leads was 2.3 mm (range, 1.3–7.1 mm). Thirty-five (18.4%) and seven leads (3.7%) had deviations exceeding twice and three times the lead body diameter, respectively. Angles between the deviation point and securing site at the skull ranged from 135–180° in 83 leads (53.2%), 45–135° in 58 (37.2%), and 0–45° in 15 (9.6%). Among 17 leads that were initially bent, 16 had less deviation compared to baseline. The lead depth increased in 35 (92.1%) of 38 leads by 1.2 mm (range, 0.1–4.7 mm).

Conclusion

The extent of lead bending should be considered during the planning and procedural phases of intracranial lead implantation for DBS.

Deep brain stimulation for the treatment of cerebral palsy: A review

Deep brain stimulation (DBS) has been used as a safe and effective neuromodulation technique for treatment of various diseases. A large number of patients suffering from movement disorders such as dyskinesia may benefit from DBS. Cerebral palsy (CP) is a group of permanent disorders mainly involving motor impairment, and medical interventions are usually unsatisfactory or temporarily active, especially for dyskinetic CP. DBS may be another approach to the treatment of CP. In this review we discuss the targets for DBS and the mechanisms of action for the treatment of CP, and focus on presurgical assessment, efficacy for dystonia and other symptoms, safety, and risks.

The Effectiveness of Deep Brain Stimulation in Dystonia: A Patient-Centered Approach

Background:

To systematically evaluate the effectiveness of deep brain stimulation of the globus pallidus internus (GPi-DBS) in dystonia on pre-operatively set functional priorities in daily living.

Methods:

Fifteen pediatric and adult dystonia patients (8 male; median age 32y, range 8–65) receiving GPi-DBS were recruited. All patients underwent a multidisciplinary evaluation before and 1-year post DBS implantation. The Canadian Occupational Performance Measure (COPM) first identified and then measured changes in functional priorities. The Burke-Fahn-Marsden Dystonia Rating Scale (BFMDRS) was used to evaluate dystonia severity.

Results:

Priorities in daily functioning substantially varied between patients but showed significant improvements on performance and satisfaction after DBS. Clinically significant COPM-score improvements were present in 7/8 motor responders, but also in 4/7 motor non-responders.

Discussion:

The use of a patient-oriented approach to measure GPi-DBS effectiveness in dystonia provides an unique insight in patients’ priorities and demonstrates that tangible improvements can be achieved irrespective of motor response.

Highlights

Deep Brain Stimulation for Spasmodic Dysphonia: A Blinded Comparison of Unilateral and Bilateral Stimulation in Two Patients

Deep brain stimulation (DBS) is a promising new therapy for patients with spasmodic dysphonia (SD). The preliminary results from our randomized controlled trial showed good clinical effects with unilateral left thalamic stimulation in 6 right- handed patients. This suggests that the pathological process underpinning SD may have a "hemisphere dominant" pathway. We describe 2 patients with concurrent essential tremor and SD who had previously undergone bilateral thalamic DBS for their limb tremor. Both patients experienced an unanticipated improvement of their SD symptoms. One patient was right-handed, and the other was mixed left-handed. To investigate the amount of SD improvement following DBS therapy in each hemisphere, 4 different settings were tested: both sides on, left side on, right side on, and both sides off. Both patients most improved following bilateral stimulation. There was, however, a powerful unilateral benefit in both patients with only a small additional benefit from bilateral stimulation. The right-handed patient improved most with left-hemisphere stimulation whereas the mixed left-handed patient improved most with right hemisphere stimulation. There was some discrepancy between the two tests applied in the second patient reflecting the known difficulties to evaluate vocal symptom improvement in SD. We discuss the possible correlation of handedness and speech hemisphere dominance as well as the need for more reliable tests to measure SD severity. Ultimately, we recommend a bilateral approach for future studies, using a patient perception test as the primary outcome and functional imaging to further investigate the correlation of handedness and the amount of hemisphere dominance in SD.

Cerebellar Deep Brain Stimulation for Acquired Hemidystonia

Background

The cerebellum's role in dystonia is increasingly recognized. Dystonia can be a disabling and refractory condition; deep brain stimulation can help many patients, but it is traditionally less effective in acquired dystonia. New surgical targets would be instrumental in providing treatment options and understanding dystonia further.

Objective

To evaluate the efficacy of deep brain stimulation of the cerebellum in acquired dystonia.

Methods

We report our management of a 37-year-old woman with severe left arm and leg dystonia, a complication of an ischemic stroke in childhood. She had already had 2 thalamotomies with only transient benefit. These procedures, in addition to her initial stroke that had damaged the basal ganglia, left traditional deep brain stimulation targets unavailable.

Results

After implantation of bilateral deep cerebellar nuclei, dystonia improved with a 40% reduction in severity on scales and subjective reports of improved posturing, gait, and pain. This improvement has been maintained for almost 2 years after implantation.

Conclusion

Cerebellar stimulation has potential for therapeutic benefit in acquired dystonia and should be further explored.

Deep brain stimulation for myoclonus dystonia syndrome: a meta-analysis with individual patient data

Good outcomes have been reported in deep brain stimulation (DBS) for myoclonus-dystonia syndrome (M-D), a heritable disease characterized by childhood-onset myoclonic jerks and dystonia in the upper body. This meta-analysis was to evaluate the clinical outcomes consecutively, compare the stimulation targets, and identify potential prognostic factors. A systematic literature search was performed on PubMed, Web of Science, and Embase. The primary outcome was the percent improvement in Burke-Fahn-Marsden Dystonia Rating Scale movement (BFMDRS-M) scores for dystonia and Unified Myoclonus Rating Scale (UMRS) scores for myoclonus at the last follow-up visit. BFMDRS-disability scores of the patients were also summarized. Pearson correlation analyses were performed to identify the myoclonus and dystonia outcome predictors. Thirty-one studies reporting 71 patients were included. There were significant improvements in BFMDRS-M and BFMDRS-disability scores in each time category and at the last follow-up visit. Mean improvement (%) in UMRS was 79.5 ± 18.2, and 94.1% of the patients showed > 50% improvement in UMRS scores at the last follow-up visit. There was a significant trend toward improved myoclonus outcome with older age at onset and shorter disease duration. Most of the adverse events were mild and transient, and pallidal stimulation seemed to be better with respect to fewer stimulation-induced events. Based on the current data, DBS is effective for even the severe M-D. Surgery at an early stage may predict a better outcome. Although targets do not serve as the outcome predictors, pallidal stimulation may be preferred due to fewer stimulation-induced events.

Quality of life outcomes after deep brain stimulation in dystonia: A systematic review

Dystonia is an incurable movement disorder which can cause not only physical but also mental problems, leading to impaired health-related quality of life (HRQoL). For patients with dystonia refractory to medical treatment, deep brain stimulation (DBS) is a well-established surgical treatment. The objective of this systematic review is to provide a better understanding of HRQoL outcomes after DBS for dystonia. A search of the literature was conducted using Medline (PubMed), Embase, and Cochrane Library databases in May 2019. HRQoL outcomes after DBS along with motor outcomes were reported in a total of 36 articles involving 610 patients: 21 articles on inherited or idiopathic isolated dystonia, 5 on tardive dystonia, 3 on cerebral palsy, 2 on myoclonus-dystonia, 1 on X-linked dystonia-parkinsonism, and 3 on mixed cohorts of different dystonia subtypes. DBS improved motor symptoms in various subtypes of dystonia. Most studies on patients with inherited or idiopathic isolated dystonia showed significant improvement in physical QoL, whereas gains in mental QoL were less robust and likely related to the complexity of associated neuropsychiatric problems. HRQoL outcomes beyond 5 years remain scarce. Although the studies on patients with other subtypes of dystonia also demonstrated improvement in HRQoL after DBS, the interpretation is difficult because of a limited number of articles with small cohorts. Most articles employed generic measures (e.g. Short Form Health Survey-36) and this highlights the critical need to develop and to utilize sensitive and disease-specific HRQoL measures. Finally, long-term HRQoL outcomes and predictors of HRQoL should also be clarified.

Clinical outcomes of pallidal deep brain stimulation for dystonia implanted using intraoperative MRI

OBJECTIVE

Lead placement for deep brain stimulation (DBS) using intraoperative MRI (iMRI) relies solely on real-time intraoperative neuroimaging to guide electrode placement, without microelectrode recording (MER) or electrical stimulation. There is limited information, however, on outcomes after iMRI-guided DBS for dystonia. The authors evaluated clinical outcomes and targeting accuracy in patients with dystonia who underwent lead placement using an iMRI targeting platform.

METHODS

Patients with dystonia undergoing iMRI-guided lead placement in the globus pallidus pars internus (GPi) were identified. Patients with a prior ablative or MER-guided procedure were excluded from clinical outcomes analysis. Burke-Fahn-Marsden Dystonia Rating Scale (BFMDRS) scores and Toronto Western Spasmodic Torticollis Rating Scale (TWSTRS) scores were assessed preoperatively and at 6 and 12 months postoperatively. Other measures analyzed include lead accuracy, complications/adverse events, and stimulation parameters.

RESULTS

A total of 60 leads were implanted in 30 patients. Stereotactic lead accuracy in the axial plane was 0.93 ± 0.12 mm from the intended target. Nineteen patients (idiopathic focal, n = 7; idiopathic segmental, n = 5; DYT1, n = 1; tardive, n = 2; other secondary, n = 4) were included in clinical outcomes analysis. The mean improvement in BFMDRS score was 51.9% ± 9.7% at 6 months and 63.4% ± 8.0% at 1 year. TWSTRS scores in patients with predominant cervical dystonia (n = 13) improved by 53.3% ± 10.5% at 6 months and 67.6% ± 9.0% at 1 year. Serious complications occurred in 6 patients (20%), involving 8 of 60 implanted leads (13.3%). The rate of serious complications across all patients undergoing iMRI-guided DBS at the authors' institution was further reviewed, including an additional 53 patients undergoing GPi-DBS for Parkinson disease. In this expanded cohort, serious complications occurred in 11 patients (13.3%) involving 15 leads (10.1%).

CONCLUSIONS

Intraoperative MRI-guided lead placement in patients with dystonia showed improvement in clinical outcomes comparable to previously reported results using awake MER-guided lead placement. The accuracy of lead placement was high, and the procedure was well tolerated in the majority of patients. However, a number of patients experienced serious adverse events that were attributable to the introduction of a novel technique into a busy neurosurgical practice, and which led to the revision of protocols, product inserts, and on-site training.

Twenty years on: Myoclonus-dystonia and ε-sarcoglycan - neurodevelopment, channel, and signaling dysfunction

Myoclonus-dystonia is a clinical syndrome characterized by a typical childhood onset of myoclonic jerks and dystonia involving the neck, trunk, and upper limbs. Psychiatric symptomatology, namely, alcohol dependence and phobic and obsessive-compulsive disorder, is also part of the clinical picture. Zonisamide has demonstrated effectiveness at reducing both myoclonus and dystonia, and deep brain stimulation seems to be an effective and long-lasting therapeutic option for medication-refractory cases. In a subset of patients, myoclonus-dystonia is associated with pathogenic variants in the epsilon-sarcoglycan gene, located on chromosome 7q21, and up to now, more than 100 different pathogenic variants of the epsilon-sarcoglycan gene have been described. In a few families with a clinical phenotype resembling myoclonus-dystonia associated with distinct clinical features, variants have been identified in genes involved in novel pathways such as calcium channel regulation and neurodevelopment. Because of phenotypic similarities with epsilon-sarcoglycan gene-related myoclonus-dystonia, these conditions can be collectively classified as "myoclonus-dystonia syndromes." In the present article, we present myoclonus-dystonia caused by epsilon-sarcoglycan gene mutations, with a focus on genetics and underlying disease mechanisms. Second, we review those conditions falling within the spectrum of myoclonus-dystonia syndromes, highlighting their genetic background and involved pathways. Finally, we critically discuss the normal and pathological function of the epsilon-sarcoglycan gene and its product, suggesting a role in the stabilization of the dopaminergic membrane via regulation of calcium homeostasis and in the neurodevelopmental process involving the cerebello-thalamo-pallido-cortical network. © 2019 International Parkinson and Movement Disorder Society.

Clinical phenotypes associated with outcomes following deep brain stimulation for childhood dystonia

OBJECTIVE

Although deep brain stimulation (DBS) is an accepted treatment for childhood dystonia, there is significant heterogeneity in treatment response and few data are available to identify ideal surgical candidates.

METHODS

Data were derived from a systematic review and individual patient data meta-analysis of DBS for dystonia in children that was previously published. Outcomes were assessed using the Burke-Fahn-Marsden Dystonia Rating Scale for movement (BFMDRS-M) and for disability (BFMDRS-D). The authors used partial least squares, bootstrapping, and permutation statistics to extract patterns of contributions of specific preoperative characteristics to relationship with distinct outcomes, in all patients and in patients with primary and secondary dystonia separately.

RESULTS

Of 301 children undergoing DBS for dystonia, 167 had primary dystonia, 125 secondary dystonia, and 9 myoclonus dystonia. Three dissociable preoperative phenotypes (latent variables) were identified and associated with the following: 1) BFMDRS-M at last follow-up; 2) relative change in BFMDRS-M score; and 3) relative change in BFMDRS-D score. The phenotype of patients with secondary dystonia, with a high BFMDRS-M score and truncal involvement, undergoing DBS at a younger age, was associated with a worse postoperative BFMDRS-M score. Children with primary dystonia involving the trunk had greater improvement in BFMDRS-M and -D scores. Those with primary dystonia of shorter duration and proportion of life with disease, undergoing globus pallidus DBS, had greater improvements in BFMDRS-D scores at long-term follow-up.

CONCLUSIONS

In a comprehensive, data-driven, multivariate analysis of DBS for childhood dystonia, the authors identified novel and dissociable patient phenotypes associated with distinct outcomes. The findings of this report may inform surgical candidacy for DBS.

Patient-adjusted deep-brain stimulation programming is time saving in dystonia patients

BACKGROUND

Deep-brain stimulation (DBS) programming for dystonia patients is a complex and time-consuming task.

OBJECTIVE

To analyze whether programming a programming paradigm based on patient's self-adjustment is practical, effective and time saving in dystonia.

METHODS

We retrospectively compared dystonia rating scales as well as the time necessary to optimize programming and the number of in-hospital visits in all patients (n = 102) operated at our center who used simple mode (SM) or advanced mode (AM) programming; the latter uses groups of different stimulation parameters and allows the patient and their caregiver to change stimulation groups at home, using the patient remote control.

RESULTS

Both AM- and SM-allocated patients improved clinically to the same extent after DBS, as assessed by the Burke-Fahn-Marsden (BFM) and the Toronto Western Spasmodic Torticollis (TWSTRS) dystonia rating scales. All subscores improved after DBS without statistically significant differences in improvement between AM and SM (BFM: - 43% vs. - 53%, p = 0.569; TWSTRS: - 63% vs. - 72%, p = 0.781). AM and SM patients reached optimization within a similar median time [5.5 months (95% CI 4.6-6.3) for AM vs. 6.2 months (4.2-7.6) for SM, p = 0.674) but patients on advanced programming needed fewer in-hospital visits to achieve the same improvement [median of 5 visits (95% CI 4-7) for AM vs. 8 visits (7-9) for SM, p = 0.008].

CONCLUSIONS

Advanced DBS programming based on patient's self-adjustment under the supervision of the treating physician is feasible, practical and significantly reduces consultation time in dystonia patients.

Intermuscular coherence as biomarker for pallidal deep brain stimulation efficacy in dystonia

OBJECTIVE

Finding a non-invasive biomarker for Globus Pallidus interna Deep Brain Stimulation (GPi-DBS) efficacy. Dystonia heterogeneity leads to a wide variety of clinical response to GPi-DBS, making it hard to predict GPi-DBS efficacy for individual patients.

METHODS

EEG-EMG recordings of twelve dystonia patients who received bilateral GPi-DBS took place pre- and 1 year post-surgery ON and OFF stimulation, during a rest, pinch, and flexion task. Dystonia severity was assessed using the BFMDRS and TWSTRS (pre- and post-surgery ON stimulation). Intermuscular coherence (IMC) and motorcortex corticomuscular coherence (CMC) were calculated. Low frequency (4-12 Hz) and beta band (13-30 Hz) peak coherences were studied.

RESULTS

Dystonia severity improved after 1 year GPi-DBS therapy (BFMDRS: 30%, median 7.8 (IQR 3-10), TWSTRS: 22%, median 6.8 (IQR 4-9)). 86% of IMC were above the 95% confidence limit. The highest IMC peak decreased significantly with GPi-DBS in the low frequency and beta band. Low frequency and beta band IMC correlated partly with dystonia severity and severity improvement. CMC generally were below the 95% confidence limit.

CONCLUSIONS

Peak low frequency IMC functioned as biomarker for GPi-DBS efficacy, and partly correlated with dystonia severity.

SIGNIFICANCE

IMC can function as biomarker. Confirmation in a larger study is needed for use in clinical practice.

Despite dystonia: natural history of delayed-onset pediatric secondary dystonia

Background: Dystonia is a movement disorder involving involuntary movements and/or postures of the limbs, trunk, neck or face. Secondary dystonia following brain injury is uncommon, with unfavorable long-term consequences. Given the limited evidence regarding pediatric secondary dystonia, this study's aim was to document the natural history of the condition and the effect of interventions on its symptomatology. Methods: We describe three cases of girls (age 8 to 11 y) who developed dystonia secondary to an acquired brain injury, received intensive rehabilitation treatments and were followed for 8-33 months post-injury. In all three cases, secondary dystonia appeared 1-3 months post-insult. Results: In none of the cases was there alleviation of dystonic symptoms over time despite physical and pharmacological interventions; in two cases the dystonic hand is now used as an assisting hand only, whereas in the third it is completely non-functional. However, despite their impairment, two girls achieved basic functional independence and one is partly independent in activities of daily living. Conclusions: Rehabilitation professionals who work with pediatric patients susceptible to developing secondary dystonia should be aware of its possible consequences and inform families and staff. Intensive task-specific training during rehabilitation may be key to regaining overall functional capabilities despite residual impairment.

Gross motor function outcomes following deep brain stimulation for childhood-onset dystonia: A descriptive report

AIM

To examine the impact of deep brain stimulation (DBS) on gross motor function in children with dystonic movement disorders.

METHOD

Prospective audit involving children implanted 2007-2015, followed for up to two years. Outcomes were evaluated across aetiological sub-groups (inherited, acquired, idiopathic) using the GMFM-88 and BFMDRS movement scale (BFM-M). The predictive value of proportion of life lived with dystonia (PLD) and baseline motor capacity were evaluated.

RESULTS

Data was available for 60 children (median surgery age 10y11mo). Inherited monogenetic dystonias demonstrated a median increase in GMFM-88 scores of 6.9% (p = 0.021) and 14.5% (p = 0.116) at one and two years. Heredodegenerative and idiopathic dystonias showed disparate responses, with non-significant changes seen in GMFM-88 and BFM-M scores, with the exception of improved one-year BFM-M scores in the idiopathic group [median change 5.5, p = 0.021]. Median GMFM-88 and BFM-M change scores were near zero for acquired dystonias, though improvement was noted in 9/18 CP cases with one-year GMFM-88 data. No significant relationship was found between PLD, or baseline GMFM-88, and GMFM-88 change following DBS.

CONCLUSION

Gross motor response to DBS is similar in profile to literature reporting results using impairment-based dystonia rating scales. Relatively consistent improvements were seen in inherited monogenetic ("primary") dystonias, while highly variable, often disappointing, gross motor responses were found in acquired, heredodegenerative, and idiopathic dystonias. In view of such response variability, alternatives to mean group studies, such as single case experimental designs with multiple replications, are needed to determine the efficacy of DBS in childhood-onset dystonias. Ongoing research is needed to identify factors that predict treatment response.

The Comprehensive Management of Cerebellar Ataxia in Adults

PURPOSE OF REVIEW

In this review, we present the multidisciplinary approach to the management of the many neurological, medical, social, and emotional issues facing patients with cerebellar ataxia.

RECENT FINDINGS

Our holistic approach to treatment, developed over the past 25 years in the Massachusetts General Hospital Ataxia Unit, is centered on the compassionate care of the patient and their family, empowering them through engagement, and including the families as partners in the healing process. We present the management of ataxia in adults, beginning with establishing an accurate diagnosis, followed by treatment of the multiple symptoms seen in cerebellar disorders, with a view to maximizing quality of life and effectively living with the consequences of ataxia. We discuss the importance of a multidisciplinary approach to the management of ataxia, including medical and non-medical management and the evidence base that supports these interventions. We address the pharmacological treatment of ataxia, tremor, and other associated movement disorders; ophthalmological symptoms; bowel, bladder, and sexual symptoms; orthostatic hypotension; psychiatric and cognitive symptoms; neuromodulation, including deep brain stimulation; rehabilitation including physical therapy, occupational therapy and speech and language pathology and, as necessary, involving urology, psychiatry, and pain medicine. We discuss the role of palliative care in late-stage disease. The management of adults with ataxia is complex and a team-based approach is essential.

Deep brain stimulation for pediatric dystonia: a meta-analysis with individual participant data

AIM

We performed a meta-analysis with individual participant data of deep brain stimulation (DBS) for dystonia in children and young people.

METHOD

Three databases (PubMed, Embase, and Web of Science) were queried from January 1999 to August 2017 with no language restrictions to identify case studies and cohort studies reporting on pediatric patients (age ≤21y) with dystonia. The primary outcomes were changes in Burke-Fahn-Marsden (BFM) or Barry-Albright Dystonia Scale scores. A mixed-effects regression was used to identify associations between clinical covariates and outcomes.

RESULTS

Of 2509 citations reviewed, 72 articles (321 children) were eligible. At last follow-up (median 12mo, 25th centile=9.0; 75th centile=32.2), 277 (86.3%) patients showed improvement in dystonia, while 66.1 percent showed clinically significant (>20%) BFM Dystonia Rating Scale-motor improvement. On multivariable hierarchical regression, older age at dystonia onset, inherited dystonia without nervous system pathology and idiopathic dystonia (vs inherited with nervous system pathology or acquired dystonia), and truncal involvement indicated a better outcome (p<0.05).

INTERPRETATION

The data suggest that DBS is effective and should be considered in selected children with inherited or idiopathic dystonia.

WHAT THIS PAPER ADDS

Deep brain stimulation is effective in selected children with inherited or idiopathic dystonia.

Unilateral pallidal stimulation for disabling dystonia due to Rasmussen's disease

OBJECTIVE

To describe an adult patient with Rasmussen's disease with focal dystonia as the most disabling symptom and the good response to unilateral globus pallidus internus (GPi) deep brain stimulation (DBS).

METHODS

Retrospective review of clinical records and diagnostic tests.

RESULTS

The patient had displayedmild focal seizures with sensory and motor symptoms on the left arm and hemiface since the age of 22. Ten years later she experienced abrupt onset of focal left dystonia involving mainly the leg. Brain MRI showed progressive right hemisphere atrophy, and  ¹⁸ fluorodeoxyglucose-positron emission tomography (¹⁸FDG-PET) showed right hypometabolism mainly over the frontal and insular regions. Brain biopsy confirmed chronic encephalitis. The dystonia became very severe and made walking extremely difficult. Different treatments including dopaminergic, anticholinergic, immunomodulatory drugs and botulinum toxin were ineffective. Finally the patient was treated with unilateral GPi DBS. Shortly after the onset of the stimulation, the dystonia started to improve. Parameters have been adjusted, and 18 months after surgery the patient is able to walk and run unaided, although a mild left leg dystonia persists.

CONCLUSION

Rasmussen's disease may be difficult to diagnose in adult patients. Associated movement disorders may be more disabling than seizures. Focal dystonia may be treated successfully with DBS.

Motor and non-motor determinants of health-related quality of life in young dystonia patients

OBJECTIVES

To systematically investigate the relationship between motor and non-motor symptoms, and health-related quality of life (HR-QoL) in children and young adults with dystonia.

METHODS

In this prospective observational cross-sectional study, 60 patients (6-25 years) with childhood-onset dystonia underwent a multidisciplinary assessment of dystonia severity (Burke-Fahn-Marsden Dystonia Rating Scale, Global Clinical Impression), motor function (Gross Motor Function Measure, Melbourne Assessment of Unilateral Upper Limb Function), pain (visual analogue scale), intelligence (Wechsler Intelligence Scale), executive functioning (Behavior Rating Inventory of Executive Function) and anxiety/depression (Child/Adult Behavior Checklist). Measures were analyzed using a principal component analysis and subsequent multiple regression to evaluate which components were associated with HR-QoL (Pediatric Quality of life Inventory) for total group, and non-lesional (primary) and lesional (secondary) subgroups.

RESULTS

Patients (29 non-lesional, 31 lesional dystonia) had a mean age of 13.6 ± 5.9 years. The principal component analysis revealed three components: 1) motor symptoms; 2) psychiatric and behavioral symptoms; and 3) pain. HR-QoL was associated with motor symptoms and psychiatric and behavioral symptoms (R2 = 0.66) for the total sample and lesional dystonia, but in the non-lesional dystonia subgroup only with psychiatric and behavioral symptoms (R2 = 0.51).

CONCLUSIONS

Non-motor symptoms are important for HR-QoL in childhood-onset dystonia. We suggest a multidisciplinary assessment of motor and non-motor symptoms to optimize individual patient management.