Bilateral pallidal deep brain stimulation for the treatment of patients with dystonia-choreoathetosis cerebral palsy: a prospective pilot study

Protocol for combined N-of-1 trials to assess cerebellar neurostimulation for movement disorders in children and young adults with dyskinetic cerebral palsy

BACKGROUND

Movement and tone disorders in children and young adults with cerebral palsy are a great source of disability. Deep brain stimulation (DBS) of basal ganglia targets has a major role in the treatment of isolated dystonias, but its efficacy in dyskinetic cerebral palsy (DCP) is lower, due to structural basal ganglia and thalamic damage and lack of improvement of comorbid choreoathetosis and spasticity. The cerebellum is an attractive target for DBS in DCP since it is frequently spared from hypoxic ischemic damage, it has a significant role in dystonia network models, and small studies have shown promise of dentate stimulation in improving CP-related movement and tone disorders.

METHODS

Ten children and young adults with DCP and disabling movement disorders with or without spasticity will undergo bilateral DBS in the dorsal dentate nucleus, with the most distal contact ending in the superior cerebellar peduncle. We will implant Medtronic Percept, a bidirectional neurostimulator that can sense and store brain activity and deliver DBS therapy. The efficacy of cerebellar DBS in improving quality of life and motor outcomes will be tested by a series of N-of-1 clinical trials. Each N-of-1 trial will consist of three blocks, each consisting of one month of effective stimulation and one month of sham stimulation in a random order with weekly motor and quality of life scales as primary and secondary outcomes. In addition, we will characterize abnormal patterns of cerebellar oscillatory activity measured by local field potentials from the intracranial electrodes related to clinical assessments and wearable monitors. Pre- and 12-month postoperative volumetric structural and functional MRI and diffusion tensor imaging will be used to identify candidate imaging markers of baseline disease severity and response to DBS.

DISCUSSION

Our goal is to test a cerebellar neuromodulation therapy that produces meaningful changes in function and well-being for people with CP, obtain a mechanistic understanding of the underlying brain network disorder, and identify physiological and imaging-based predictors of outcomes useful in planning further studies.

TRIAL REGISTRATION

ClinicalTrials.gov NCT06122675, first registered November 7, 2023.

Protocol for combined N-of-1 trials to assess cerebellar neurostimulation for movement disorders in children and young adults with dyskinetic cerebral palsy

Background

Movement and tone disorders in children and young adults with cerebral palsy are a great source of disability. Deep brain stimulation (DBS) of basal ganglia targets has a major role in the treatment of isolated dystonias, but its efficacy in dyskinetic cerebral palsy (DCP) is lower, due to structural basal ganglia and thalamic damage and lack of improvement of comorbid choreoathetosis and spasticity. The cerebellum is an attractive target for DBS in DCP since it is frequently spared from hypoxic ischemic damage, it has a significant role in dystonia network models, and small studies have shown promise of dentate stimulation in improving CP-related movement and tone disorders.

Methods

Ten children and young adults with DCP and disabling movement disorders with or without spasticity will undergo bilateral DBS in the dorsal dentate nucleus, with the most distal contact ending in the superior cerebellar peduncle. We will implant Medtronic Percept, a bidirectional neurostimulator that can sense and store brain activity and deliver DBS therapy. The efficacy of cerebellar DBS in improving quality of life and motor outcomes will be tested by a series of N-of-1 clinical trials. Each N-of-1 trial will consist of three blocks, each consisting of one month of effective stimulation and one month of sham stimulation in a random order with weekly motor and quality of life scales as primary and secondary outcomes. In addition, we will characterize abnormal patterns of cerebellar oscillatory activity measured by local field potentials from the intracranial electrodes related to clinical assessments and wearable monitors. Pre- and 12-month postoperative volumetric structural and functional MRI and diffusion tensor imaging will be used to identify candidate imaging markers of baseline disease severity and response to DBS.

Discussion

Our goal is to test a cerebellar neuromodulation therapy that produces meaningful changes in function and well-being for people with CP, obtain a mechanistic understanding of the underlying brain network disorder, and identify physiological and imaging-based predictors of outcomes useful in planning further studies.

Trial registration

ClinicalTrials.gov NCT06122675, first registered November 7, 2023.

Quality of life outcomes after deep brain stimulation in acquired dystonia: a systematic review and meta-analysis

BACKGROUND

Dystonia is a condition that affects the ability to control the movement and function of the body's muscles. It can cause not only physical problems, but also mental problems, resulting in impaired health-related quality of life (HRQoL). However, the effect of deep brain stimulation on quality of life in acquired dystonia remains unclear.

METHODS

We conducted a systematic literature review from January 2000 to October 2022，determined the eligible studies, and performed a meta-analysis of HRQoL outcomes based on the Short-Form Health Survey-36 (SF-36) after DBS to evaluate the effects of DBS on physical and mental QoL.

RESULTS

A total of 14 studies met the inclusion criteria and were systematically reviewed. A comprehensive meta-analysis was performed for 9 studies that reported physical and psychological data or physical component summary (PCS), or mental component summary (MCS) for SF-36. The mean (SD) age at DBS implantation was 34.29 (10.3) years, and the follow-up period after implantation was 2.21 (2.80) years. The random effects model meta-analysis revealed that both physical and mental domains of the SF-36 improved following DBS. There was no statistically significant difference between the physical domains (effect size=1.34; p<0.0001) and the mental domains (effect size=1.38; p<0.0001).

CONCLUSION

This is the first meta-analysis that demonstrates significant benefits in HRQoL following DBS in patients with acquired dystonia. There were significant improvements in both physical QoL and mental QoL.

Cognitive Functioning and Assessment in Adults with Cerebral Palsy: A Scoping Review

In this scoping review, we summarize the current knowledge of cognitive functioning in adults with cerebral palsy (CP), and identify the neuropsychological tests typically used in this population. 39 studies from the period January 1990 - August 2023 were included in the review, and they differ widely in their aims and approach to studying cognition. Very few studies have cognitive assessment as their core aim and use a neuropsychological test battery. The included studies show great variability in reported intelligence and cognitive functioning in adults with CP, and cognitive deficits have been reported in all cognitive domains. Most of the studies suffer from methodological limitations, and there is ample room for improvement within the field. We conclude by suggesting a number of recommendations that may contribute to increasing our understanding of cognitive impairments in adults with CP.

Forniceal deep brain stimulation in a mouse model of Rett syndrome increases neurogenesis and hippocampal memory beyond the treatment period

BACKGROUND

Rett syndrome (RTT), caused by mutations in the X-linked gene encoding methyl-CpG binding protein 2 (MeCP2), severely impairs learning and memory. We previously showed that forniceal deep brain stimulation (DBS) stimulates hippocampal neurogenesis with concomitant improvements in hippocampal-dependent learning and memory in a mouse model of RTT.

OBJECTIVES

To determine the duration of DBS benefits; characterize DBS effects on hippocampal neurogenesis; and determine whether DBS influences MECP2 genotype and survival of newborn dentate granular cells (DGCs) in RTT mice.

METHODS

Chronic DBS was delivered through an electrode implanted in the fimbria-fornix. We tested separate cohorts of mice in contextual and cued fear memory at different time points after DBS. We then examined neurogenesis, DGC apoptosis, and the expression of brain-derived neurotrophic factor (BDNF) and vascular endothelial growth factor (VEGF) after DBS by immunohistochemistry.

RESULTS

After two weeks of forniceal DBS, memory improvements lasted between 6 and 9 weeks. Repeating DBS every 6 weeks was sufficient to maintain the improvement. Forniceal DBS stimulated the birth of more MeCP2-positive than MeCP2-negative DGCs and had no effect on DGC survival. It also increased the expression of BDNF but not VEGF in the RTT mouse dentate gyrus.

CONCLUSION

Improvements in learning and memory from forniceal DBS in RTT mice extends well beyond the treatment period and can be maintained by repeated DBS. Stimulation of BDNF expression correlates with improvements in hippocampal neurogenesis and memory benefits.

Long-Term Follow-Up of Pediatric Patients with Dyskinetic Cerebral Palsy and Deep Brain Stimulation

BACKGROUND

Deep brain stimulation (DBS) has been increasingly used in the management of dyskinetic cerebral palsy (DCP). Data on long-term effects and the safety profile are rare.

OBJECTIVES

We assessed the efficacy and safety of pallidal DBS in pediatric patients with DCP.

METHODS

The STIM-CP trial was a prospective, single-arm, multicenter study in which patients from the parental trial agreed to be followed-up for up to 36 months. Assessments included motor and non-motor domains.

RESULTS

Of the 16 patients included initially, 14 (mean inclusion age 14 years) were assessed. There was a significant change in the (blinded) ratings of the total Dyskinesia Impairment Scale at 36 months. Twelve serious adverse events (possibly) related to treatment were documented.

CONCLUSION

DBS significantly improved dyskinesia, but other outcome parameters did not change significantly. Investigations of larger homogeneous cohorts are needed to further ascertain the impact of DBS and guide treatment decisions in DCP. © 2023 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.

Bilateral globus pallidus interna deep brain stimulation in the treatment of mixed cerebral palsy in ataxia with dyskinesia: a case report

Background

Cerebral palsy (CP), a complex syndrome with multiple etiologies, is characterized by a range of movement disorders within the hypokinetic and hyperkinetic spectrum (dystonia or choreoathetosis). CP is often accompanied by neurological and psychiatric signs, such as spasticity, ataxia, and cognitive disorders. Although current treatment options for CP include pharmacological interventions, rehabilitation programs, and spasticity relief surgery, their effectiveness remains limited. Deep brain stimulation (DBS) has demonstrated significant effectiveness in managing dyskinesia; however, its potential therapeutic effect on CP remains determined.

Methods

We present a case of a 44-year-old Asian female who was born as a twin with neonatal ischemic-hypoxic encephalopathy due to prolonged labor and delivery. She was diagnosed with CP at the age of 1 year. The patient exhibited delayed development compared to her peers and presented with various symptoms, including slurred speech, broad-based gait, horseshoe inversion of the right lower extremity, involuntary shaking of the upper extremities bilaterally, and hypotonia and showed no improvement with levodopa therapy. Two years ago, she developed progressive head tremors, which worsened during periods of tension and improved during sleep. As medical treatments proved ineffective and there were no contraindications to surgery, we performed bilateral globus pallidus interna DBS (GPi-DBS) to alleviate her motor dysfunction.

Results

Following a 6-month follow-up, the patient demonstrated significant improvements in motor symptoms, including head and limb tremors and dystonia. In addition, significant improvement was observed in her overall psychological well-being, as evidenced by reduced anxiety and depression levels.

Conclusion

DBS is an effective treatment for dyskinesia symptoms associated with CP in adults. Moreover, its effectiveness may continue to increase over time.

Deep brain stimulation for hemidystonia: A meta-analysis with individual patient data

BACKGROUND

Deep brain stimulation (DBS) is now well established for the treatment of dystonic movement disorders. There is limited data, however, on the efficacy of DBS in hemidystonia. This meta-analysis aims to summarize the published reports on DBS for hemidystonia of different etiologies, to compare different stimulation targets, and to evaluate clinical outcome.

METHODS

A systematic literature review was performed on PubMed, Embase and Web of Science to identify appropriate reports. The primary outcome variables were the improvement in the Burke-Fahn-Marsden Dystonia Rating Scale movement (BFMDRS-M) and disability (BFMDRS-D) scores for dystonia.

RESULTS

Twenty-two reports (39 patients; 22 with pallidal stimulation, 4 with subthalamic stimulation, 3 with thalamic stimulation, and 10 with combined target stimulation) were included. Mean age at surgery was 26.8 years. Mean follow-up time was 31.72 months. An overall mean improvement of 40% in the BFMDRS-M score was achieved (range 0%-94%), which was paralleled by a mean improvement of 41% in the BFMDRS-D score. When considering a 20% cut-off for improvement, 23/39 patients (59%) would qualify as responders. Hemidystonia due to anoxia did not significantly improve with DBS. Several limitations of the results must be considered, most importantly the low level of evidence and the small number of reported cases.

CONCLUSION

Based on the results of the current analysis, DBS can be considered as a treatment option for hemidystonia. The posteroventral lateral GPi is the target used most often. More research is needed to understand the variability in outcome and to identify prognostic factors.

Preventing incubation of drug craving to treat drug relapse: from bench to bedside

In 1986, Gawin and Kleber reported a progressive increase in cue-induced drug craving in individuals with cocaine use disorders during prolonged abstinence. After years of controversy, as of 2001, this phenomenon was confirmed in rodent studies using self-administration model, and defined as the incubation of drug craving. The intensification of cue-induced drug craving after withdrawal exposes abstinent individuals to a high risk of relapse, which urged us to develop effective interventions to prevent incubated craving. Substantial achievements have been made in deciphering the neural mechanisms, with potential implications for reducing drug craving and preventing the relapse. The present review discusses promising drug targets that have been well investigated in animal studies, including some neurotransmitters, neuropeptides, neurotrophic factors, and epigenetic markers. We also discuss translational exploitation and challenges in the field of the incubation of drug craving, providing insights into future investigations and highlighting the potential of pharmacological interventions, environment-based interventions, and neuromodulation techniques.

Probabilistic mapping of deep brain stimulation in childhood dystonia

OBJECTIVES

In adults with dystonia Probabilistic Stimulation Mapping (PSM) has identified putative "sweet spots" for stimulation. We aimed to apply PSM to a cohort of Children and Young People (CYP) following DBS surgery.

METHODS

Pre-operative MRI and post-operative CT images were co-registered for 52 CYP undergoing bilateral pallidal DBS (n = 31 genetic/idiopathic dystonia, and n = 21 Cerebral Palsy (CP)). DBS electrodes (n = 104) were automatically detected, and Volumes of Tissue Activation (VTA) derived from individual patient stimulation settings. VTAs were normalised to the MNI105 space, weighted by percentage improvement in Burke-Fahn-Marsden Dystonia Rating scale (BFMDRS) at one-year post surgery and mean improvement was calculated for each voxel.

RESULTS

For the genetic/idiopathic dystonia group, BFMDRS improvement was associated with stimulation across a broad volume of the GPi. A spatial clustering of the upper 25th percentile of voxels corresponded with a more delineated volume within the posterior ventrolateral GPi. The MNI coordinates of the centroid of this volume (X = -23.0, Y = -10.5 and Z = -3.5) were posterior and superior to the typical target for electrode placement. Volume of VTA overlap with a previously published "sweet spots" correlated with improvement following surgery. In contrast, there was minimal BFMDRS improvement for the CP group, no spatial clustering of efficacious clusters and a correlation between established "sweet spots" could not be established.

CONCLUSIONS

PSM in CYP with genetic/idiopathic dystonia suggests the presence of a "sweet spot" for electrode placement within the GPi, consistent with previous studies. Further work is required to identify and validate putative "sweet spots" across different cohorts of patients.

Bilateral pallidotomy for acquired or heredodegenerative generalized dystonia in children

OBJECTIVE

Dystonias are relatively rare disorders characterized by sustained or intermittent muscle contractions causing abnormal movements or postures. Generalized dystonia is a therapeutic challenge because medications are unable to control dystonia adequately in most patients. These patients may be candidates for surgical therapy. The commonly used surgical procedures in these patients are pallidotomy and deep brain stimulation. Limited studies are available on the role of pallidotomy in children with acquired/heredodegenerative generalized dystonia. The objective of this study was to describe the authors’ experience with bilateral pallidotomy in this group of patients.

METHODS

The authors retrospectively reviewed all pediatric patients (less than 18 years of age) with acquired/heredodegenerative generalized dystonia who underwent bilateral simultaneous pallidotomy at their center between January 2014 and January 2021. Burke-Fahn-Marsden Dystonia Rating Scale (BFMDRS) scores before and after surgery were recorded. Complications arising after the procedure were recorded as well.

RESULTS

Ten patients (8 male and 2 female) with a mean (range) age of 11.1 (5–17) years were included in this study. The mean duration between disease onset and surgical intervention was 3.9 years. Two patients presented in status dystonicus. The mean ± SD (range) preoperative BFMDRS score of the patients without status dystonicus (n = 8) was 80 ± 18.9 (59.5–108). The mean ± SD BFMDRS score at the time of discharge from the hospital after surgery was 58.8 ± 37.9. Three patients had more than 20% change in BFMDRS score at the time of discharge from the hospital. The mean improvement was 25.5% at the end of 1 year. Of 5 surviving patients in the non–status dystonicus group, 3 patients had more than 40% change in BFMDRS score while the other 2 patients developed recurrence at the last follow-up (4.5 years). Status dystonicus abated after bilateral pallidotomy in both patients. Permanent bulbar complications were seen in 2 patients.

CONCLUSIONS

Bilateral pallidotomy may result in clinically significant improvement in children with acquired/heredodegenerative generalized dystonia, although the benefits should be closely weighed against the risk of irreversible bulbar dysfunction. It is a viable option for children in resource-limited settings.

Deep brain stimulation in dystonia: factors contributing to variability in outcome in short and long term follow-up

PURPOSE OF REVIEW

Deep brain stimulation (DBS) is currently the most effective treatment for medically refractory dystonia with globus pallidus internus (GPi) usually the preferred target. Despite the overall success of DBS in dystonia, there remains variability in treatment outcome in both short and long-term follow-up, due to various factors. Factors contributing to variability in outcome comprise 'Dystonia Related' including dystonia classification, semiology, duration, body distribution, orthopaedic deformity, aetiology and genetic cause. The majority of these factors are identifiable from clinical assessment, brain MRI and genetic testing, and therefore merit careful preoperative consideration. 'DBS related' factors include brain target, accuracy of lead placement, stimulation parameters, time allowed for response, neurostimulation technology employed and DBS induced side-effects. In this review, factors contributing to variability in short and long-term dystonia DBS outcome are reviewed and discussed.

RECENT FINDINGS

The recognition of differential DBS benefit in monogenic dystonia, increasing experience with subthalamic nucleus (STN) DBS and in DBS for Meige syndrome, elucidation of DBS side effects and novel neurophysiological and imaging techniques to assist in predicting clinical outcome.

SUMMARY

Improved understanding of factors contributing to variability of DBS outcome in dystonia may assist in patient selection and predicting surgical outcomes.

Quality of Life after Deep Brain Stimulation of Pediatric Patients With Dyskinetic Cerebral Palsy: A Prospective, Single-Arm, Multicenter Study With a Subsequent Randomized Double-Blind Crossover (STIM-CP)

BACKGROUND

Patients with dyskinetic cerebral palsy are often severely impaired with limited treatment options. The effects of deep brain stimulation (DBS) are less pronounced than those in inherited dystonia but can be associated with favorable quality of life outcomes even in patients without changes in dystonia severity.

OBJECTIVE

The aim is to assess DBS effects in pediatric patients with pharmacorefractory dyskinetic cerebral palsy with focus on quality of life.

METHODS

The method used is a prospective, single-arm, multicenter study. The primary endpoint is improvement in quality of life (CPCHILD [Caregiver Priorities & Child Health Index of Life with Disabilities]) from baseline to 12 months under therapeutic stimulation. The main key secondary outcomes are changes in Burke-Fahn-Marsden Dystonia Rating Scale, Dyskinesia Impairment Scale, Gross Motor Function Measure-66, Canadian Occupational Performance Measure (COPM), and Short-Form (SF)-36. After 12 months, patients were randomly assigned to a blinded crossover to receive active or sham stimulation for 24 hours each. Severity of dystonia and chorea were blindly rated. Safety was assessed throughout. The trial was registered at ClinicalTrials.gov, number NCT02097693.

RESULTS

Sixteen patients (age: 13.4 ± 2.9 years) were recruited by seven clinical sites. Primary outcome at 12-month follow-up is as follows: mean CPCHILD increased by 4.2 ± 10.4 points (95% CI [confidence interval] -1.3 to 9.7; P = 0.125); among secondary outcomes: improvement in COPM performance measure of 1.1 ± 1.5 points (95% CI 0.2 to 1.9; P = 0.02) and in the SF-36 physical health component by 5.1 ± 6.2 points (95% CI 0.7 to 9.6; P = 0.028). Otherwise, there are no significant changes.

CONCLUSION

Evidence to recommend DBS as routine treatment to improve quality of life in pediatric patients with dyskinetic cerebral palsy is not yet sufficient. Extended follow-up in larger cohorts will determine the impact of DBS further to guide treatment decisions in these often severely disabled patients.

Predicting Outcome in a Cohort of Isolated and Combined Dystonia within Probabilistic Brain Mapping

Background

Probabilistic brain mapping is a promising tool to estimate the expected benefit of pallidal deep brain stimulation (GPi‐DBS) in patients with isolated dystonia (IsoD).

Objectives

To investigate the role of probabilistic mapping in combined dystonia (ComD).

Methods

We rendered the pallidal atlas and the volume of tissue activated (VTA) for a cohort of patients with IsoD (n = 20) and ComD (n = 10) that underwent GPi‐DBS. The VTA was correlated with clinical improvement. Afterwards, each VTA was applied on the previously published probabilistic model (Reich et al., 2019). The correlation between predicted and observed clinical benefit was studied in a linear regression model.

Results

A good correlation between observed and predicted outcome was found for both patients with IsoD (n = 14) and ComD (n = 7) (r² = 0.32; P < 0.05). In ComD, 42% of the variance in DBS response is explained by VTA‐based outcome map.

Conclusion

A probabilistic model would be helpful in clinical practice to circumvent unpredictable and less impressive motor results often found in ComD.

The immediate effect of different loads does not alter muscle co-activation of the upper limb in young adults with dyskinetic cerebral palsy

BACKGROUND

There is insufficient information on muscle co-activation in the upper limbs to help healthcare providers develop treatment programs for patients with dyskinetic cerebral palsy (DCP).

RESEARCH QUESTION

Is the degree of muscle co-activation greater in adults with DCP than in healthy individuals? Does the use of different arm weights modify co-contraction in individuals with PCD?

METHODS

Fourteen healthy individuals (control group [CG]) and 14 individuals with DCP (dyskinetic group [DG]) participated in the study. The degree of muscle co-activation of the dominant limb during drinking from a mug was compared between the two groups. The task was divided into a going, adjusting, and returning phase. In the DG, an analysis was also performed on using an arm weight during the functional task. The loads corresponded to 10, 20, and 30 % of maximum isometric muscle strength measured in each participant.

RESULTS

In comparing the two groups, the DG exhibited a greater muscle co-activation in the shoulder and elbow muscles during the going phase, the shoulder, elbow, and wrist during the adjusting phase; and the elbow during the returning phase. The DG also showed a greater mean index of curvature (MIC), time to perform the movement phases, and lesser mean velocity (Vm) to drinking. In analyzing the DG's arm weight, no effect on co-activation, MIC, time to perform the movement phases, and Vm to drinking were found with the loads tested (p > 0.05).

CONCLUSION

Muscle co-activation is increased in adults with DCP in comparison to healthy individuals. Moreover, arm weight during the functional activity of drinking from a mug did not alter co-activation, although an immediate effect was expected.

Pharmacological and neurosurgical interventions for individuals with cerebral palsy and dystonia: a systematic review update and meta-analysis

AIM

To update a systematic review of evidence published up to December 2015 for pharmacological/neurosurgical interventions among individuals with cerebral palsy (CP) and dystonia.

METHOD

Searches were updated (January 2016 to May 2020) for oral baclofen, trihexyphenidyl, benzodiazepines, clonidine, gabapentin, levodopa, botulinum neurotoxin (BoNT), intrathecal baclofen (ITB), and deep brain stimulation (DBS), and from database inception for medical cannabis. Eligible studies included at least five individuals with CP and dystonia and reported on dystonia, goal achievement, motor function, pain/comfort, ease of caregiving, quality of life (QoL), or adverse events. Evidence certainty was evaluated using GRADE.

RESULTS

Nineteen new studies met inclusion criteria (two trihexyphenidyl, one clonidine, two BoNT, nine ITB, six DBS), giving a total of 46 studies (four randomized, 42 non-randomized) comprising 915 participants when combined with those from the original systematic review. Very low certainty evidence supported improved dystonia (clonidine, ITB, DBS) and goal achievement (clonidine, BoNT, ITB, DBS). Low to very low certainty evidence supported improved motor function (DBS), pain/comfort (clonidine, BoNT, ITB, DBS), ease of caregiving (clonidine, BoNT, ITB), and QoL (ITB, DBS). Trihexyphenidyl, clonidine, BoNT, ITB, and DBS may increase adverse events. No studies were identified for benzodiazepines, gabapentin, oral baclofen, and medical cannabis.

INTERPRETATION

Evidence evaluating the use of pharmacological and neurosurgical management options for individuals with CP and dystonia is limited to between low and very low certainty. What this paper adds Meta-analysis suggests that intrathecal baclofen (ITB) and deep brain stimulation (DBS) may improve dystonia and pain. Meta-analysis suggests that DBS may improve motor function. Clonidine, botulinum neurotoxin, ITB, and DBS may improve achievement of individualized goals. ITB and DBS may improve quality of life. No direct evidence is available for oral baclofen, benzodiazepines, gabapentin, or medical cannabis.

Evolution of Globus Pallidus Targeting for Parkinson's and Dystonia Deep Brain Stimulation: A 15-Year Experience

Objective: The aim of this study is to evaluate the evolution of GPi DBS targeting.

Methods: This retrospective, single-center study included patients implanted with GPi DBS leads for dystonia or PD during the years 2004 to 2018 at the University of Florida Fixel Institute for Neurological Diseases. Each patient underwent a high-resolution targeting study on the day prior to the surgery, which was fused with a high resolution CT scan that was acquired on the day of the procedure. Intraoperative target location was selected using a digitized 3D Schaltenbrand-Bailey atlas. All patients underwent a high-resolution head CT scan without contrast approximately one month after lead implantation and accurate measurement of neuroanatomical lead position was acquired after fusion of pre-operative and post-operative image studies.

Results: We analyzed 253 PD patients with 352 leads and 80 dystonia patients with 141 leads. During 15 years of follow-up, lead locations in the PD group migrated more laterally (β = 0.09, p < 0.0001), posteriorly [slope (β) = 0.04, p < 0.05], and dorsally (β = 0.07, p < 0.001), whereas leads in the dystonia group did not significantly change position aside from a trend in the dorsal direction (β = 0.06, p = 0.053).

Conclusion: The evolving target likely results from multiple factors including improvements in targeting techniques and clinical feedback intraoperatively and post-operatively. Our demonstrates the potential importance of a systematic post-operative DBS lead measurement protocol to ensure quality control and to inform and optimize DBS programming.

Longterm Improvement After Cessation of Chronic Deep Brain Stimulation in Acquired Dystonia

Introduction

Deep brain stimulation (DBS) has become an accepted treatment for inherited and idiopathic dystonia but less so for acquired dystonia. Patients benefit from long-term improvement with chronic DBS. Prolonged benefit over months has even been reported after cessation of stimulation on long-term follow-up.

Case report

We report a case of a 25-year-old man with acquired dystonia who had sustained symptom improvement despite battery depletion after 6.5 years of chronic bilateral thalamic and pallidal DBS.

Discussion

We posit that chronic pallidal DBS can be a genuine disease-modifying treatment in single patients with dystonia with regard to its long-term effect even after prolonged discontinuation.

Highlights

Chronic deep brain stimulation (DBS) is an approved treatment for idiopathic and inherited dystonia. During the early course of chronic stimulation, cessation of DBS due to battery depletion results in rapid worsening of symptoms and rapid battery replacement is required. Few reports of sustained symptom relief in idiopathic dystonia have been published. We report a case of sustained symptom relief in acquired dystonia after DBS cessation which likely reflects neuroplasticity changes with a disease-modifying impact.

Deep Brain Stimulation of the Globus Pallidus Internus for Secondary Dystonia: Clinical Cases and Systematic Review of the Literature Regarding the Effectiveness of Globus Pallidus Internus versus Subthalamic Nucleus

OBJECTIVE

Deep brain stimulation (DBS) is a frequently applied therapy in primary dystonia. For secondary dystonia, the effects can be less favorable. We share our long-term findings in 9 patients with severe secondary dystonia and discuss these findings in the light of the literature.

METHODS

Patients who had undergone globus pallidus internus (GPi)-DBS for secondary dystonia were included. Burke-Fahn-Marsden Dystonia Rating Scale (BFMDRS) scores, clinical improvement rates, follow-up periods, stimulation parameters and the need for internal pulse generator replacements were analyzed. The PubMed and Google Scholar databases were searched for articles describing GPi-DBS and subthalamic nucleus (STN)-DBS only for secondary dystonia cases. Keywords were "dystonia," "deep brain stimulation," "GPi," "dystonia," "deep brain stimulation," and "STN."

RESULTS

A total of 9 secondary dystonia patients (5 male, 4 female) had undergone GPi-DBS with microelectrode recording in our units. The mean follow-up period was 29 months. The average BFMDRS score was 58.2 before the surgery, whereas the mean value was 36.5 at the last follow-up of the patients (mean improvement, 39%; minimum, 9%; maximum, 63%). In the literature review, we identified 264 GPi-DBS cases (mean follow-up, 19 months) in 72 different articles about secondary dystonia. The mean BFMDRS improvement rate was 52%. In 146 secondary dystonia cases, reported in 19 articles, STN-DBS was performed. The average follow-up period was 20 months and the improvement in BFMDRS score was 66%.

CONCLUSIONS

Although GPi-DBS has favorable long-term efficacy and safety in the treatment of patients with secondary dystonia, STN seems a promising target for stimulation in patients with secondary dystonia. Further studies including a large number of patients, longer follow-up periods, and more homogenous patients are necessary to establish the optimal target for DBS in the management of secondary dystonias.

Deep Brain Stimulation for Pediatric Dystonia

Dystonia is one of the most common pediatric movement disorders and can have a profound impact on the lives of children and their caregivers. Response to pharmacologic treatment is often unsatisfactory. Deep brain stimulation (DBS) has emerged as a promising treatment option for children with medically refractory dystonia. In this review we highlight the relevant literature related to DBS for pediatric dystonia, with emphasis on the background, indications, prognostic factors, challenges, and future directions of pediatric DBS.

Globus Pallidus Internus Deep Brain Stimulation Using Frame-Based vs. Frameless Stereotaxy in Dystonia: A Single-Center Experience

Objective: Bilateral globus pallidus internus deep brain stimulation (GPi-DBS) is an established and effective therapy for primary refractory dystonia. However, the comparison of frameless vs. frame-based DBS surgery technique is still controversial. This retrospective study aims to compare the clinical outcome of two GPi-DBS surgical techniques for patients affected by primary generalized or multi-segmental dystonia.

Methods: For lead's stereotaxic placement, 10 patients underwent frame-based surgery and the other 10 subjects DBS surgery with a frameless technique. Clinical features were evaluated at baseline and 6 and 12 months after surgery by means of the Burke–Fahn–Marsden Dystonia Rating Scale.

Results: Frame-based GPi-DBS and frameless stereotaxic group revealed a comparable clinical outcome with no surgical complications.

Conclusions: Frameless technique is safe and well-tolerated by patients and showed similar effectiveness of the frame-based stereotaxic surgery during GPi-DBS for primary dystonia. Notably, it could be a valid alternative solution because of the great advantage in improving the patient's discomfort during awake surgery.

Deep Brain Stimulation and Hypoxemic Perinatal Encephalopathy: State of Art and Perspectives

Cerebral palsy (CP) is a heterogeneous group of non-progressive syndromes with lots of clinical variations due to the extent of brain damages and etiologies. CP is majorly defined by dystonia and spasticity. The treatment of acquired dystonia in CP is very difficult. Many pharmacological treatments have been tried and surgical treatment consists of deep brain stimulation (continuous electrical neuromodulation) of internal globus pallidus (GPi). A peculiar cause of CP is neonatal encephalopathy due to an anoxic event in the perinatal period. Many studies showed an improvement of dystonia in CP patients with bilateral GPi DBS. However, it remains a variability in the range of 1% to 50%. Published case-series concerned mainly small population with a majority of adult patients. Selection of patients according to the clinical pattern, to the brain lesions observed on classical imaging and to DTI is the key of a high success rate of DBS in children with perinatal hypoxemic encephalopathy. Only a large retrospective study with a high number of patients in a homogeneous pediatric population with a long-term follow-up or a prospective multicenter trial investigation could answer with a high degree of certitude of the real interest of this therapeutic in children with hypoxemic perinatal encephalopathy.

Subthalamic Nucleus Deep Brain Stimulation Lessens Acquired Dystonia: Report of Two Patients and Systematic Review of Published Cases

INTRODUCTION

Deep brain stimulation (DBS) of the subthalamic nucleus (STN) is an efficient treatment of primary dystonia. Few studies have reported the effect of STN-DBS on secondary or acquired dystonia.

METHODS

We reported 2 patients with acquired dystonia treated by subthalamic DBS and followed up for 24 months, besides providing a systematic review and meta-analysis of published series.

RESULTS/CONCLUSIONS

Both patients had thalamic vascular or autoimmune lesions within the ventral and the pulvinar nuclei. A reduction of 67.2% on the Burke-Fahn-Marsden Dystonia Rating Scale and 90% improvement in disability scores were shown in the first patient, while the second patient showed a lower reduction in both dystonia symptoms (28.6%) and disability scores (44%). Both patients had a significant mean improvement in the quality of life (62.5% in the first and 57.9% in the second) and were free of drugs postoperatively. A systematic review showed a mean follow-up of 13 months in 19 patients, including our 2 patients. The review showed a significant Burke-Fahn-Marsden Dystonia Scale (BFMDRS) score median reduction of 19 points (52.4%; confidence interval [CI]: 11.0-25.0) and a significant median reduction of 6 points in disability scores (44.5%; 95% CI: 4.0-14.0), thereby improving quality of life. Age at surgery was inversely correlated with postoperative improvement (r = 0.63; p = 0.039). Hemidystonia had a nonsignificant better improvement than generalized dystonia (55.3 vs. 43.5%; p = 0.4433). No association between etiology and postoperative improvement and no serious complications were found. Although few data reported so far, subthalamic DBS is likely efficient for acquired dystonia.

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.

Adults with Cerebral Palsy Require Ongoing Neurologic Care: A Systematic Review

Cerebral palsy (CP) neurologic care and research efforts typically focus on children. However, most people with CP are adults. Adults with CP are at increased risk of new neurologic conditions, such as stroke and myelopathy, that require ongoing neurologic surveillance to distinguish them from baseline motor impairments. Neurologic factors could also contribute to the motor function decline, chronic pain, and chronic fatigue that are commonly experienced by adults with CP. Based on a systematic literature review, we suggest (1) guidelines for neurologic surveillance and neurologist referral and (2) clinical research questions regarding the evolving neurologic risks for adults with CP. ANN NEUROL 2021;89:860-871.

[Deep brain stimulation in neurological and psychiatric diseases]

Die invasive Hirnstimulation (tiefe Hirnstimulation [THS], „deep brain stimulation“ [DBS]) ist mittlerweile ein etabliertes Therapieverfahren bei einer Reihe neurologischer Erkrankungen insbesondere Bewegungsstörungen. Die Anzahl der mit einer THS versorgten Patienten steigt stetig, die technische Entwicklung der THS-Systeme schreitet voran und neue Indikationen werden aktuell in Studien überprüft. Im folgenden Beitrag soll ein Überblick über die aktuellen Indikationen und ein Ausblick auf zukünftige Entwicklungen der THS bei Bewegungsstörungen und psychiatrischen Erkrankungen gegeben werden.

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.

Mapping efficacious deep brain stimulation for pediatric dystonia

OBJECTIVE

The objective of this study was to report the authors' experience with deep brain stimulation (DBS) of the internal globus pallidus (GPi) as a treatment for pediatric dystonia, and to elucidate substrates underlying clinical outcome using state-of-the-art neuroimaging techniques.

METHODS

A retrospective analysis was conducted in 11 pediatric patients (6 girls and 5 boys, mean age 12 ± 4 years) with medically refractory dystonia who underwent GPi-DBS implantation between June 2009 and September 2017. Using pre- and postoperative MRI, volumes of tissue activated were modeled and weighted by clinical outcome to identify brain regions associated with clinical outcome. Functional and structural networks associated with clinical benefits were also determined using large-scale normative data sets.

RESULTS

A total of 21 implanted leads were analyzed in 11 patients. The average follow-up duration was 19 ± 20 months (median 5 months). Using a 7-point clinical rating scale, 10 patients showed response to treatment, as defined by scores < 3. The mean improvement in the Burke-Fahn-Marsden Dystonia Rating Scale motor score was 40% ± 23%. The probabilistic map of efficacy showed that the voxel cluster most associated with clinical improvement was located at the posterior aspect of the GPi, comparatively posterior and superior to the coordinates of the classic GPi target. Strong functional and structural connectivity was evident between the probabilistic map and areas such as the precentral and postcentral gyri, parietooccipital cortex, and brainstem.

CONCLUSIONS

This study reported on a series of pediatric patients with dystonia in whom GPi-DBS resulted in variable clinical benefit and described a clinically favorable stimulation site for this cohort, as well as its structural and functional connectivity. This information could be valuable for improving surgical planning, simplifying programming, and further informing disease pathophysiology.

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.

Thalamic deep brain stimulation for acquired dystonia in children and young adults: a phase 1 clinical trial

OBJECTIVE

The aim of this study was to evaluate the feasibility and preliminary efficacy and safety of combined bilateral ventralis oralis posterior/ventralis intermedius (Vop/Vim) deep brain stimulation (DBS) for the treatment of acquired dystonia in children and young adults. Pallidal DBS is efficacious for severe, medication-refractory isolated dystonia, providing 50%-60% long-term improvement. Unfortunately, pallidal stimulation response rates in acquired dystonia are modest and unpredictable, with frequent nonresponders. Acquired dystonia, most commonly caused by cerebral palsy, is more common than isolated dystonia in pediatric populations and is more recalcitrant to standard treatments. Given the limitations of pallidal DBS in acquired dystonia, there is a need to explore alternative brain targets. Preliminary evidence has suggested that thalamic stimulation may be efficacious for acquired dystonia.

METHODS

Four participants, 3 with perinatal brain injuries and 1 with postencephalitic symptomatic dystonia, underwent bilateral Vop/Vim DBS and bimonthly evaluations for 12 months. The primary efficacy outcome was the change in Burke-Fahn-Marsden Dystonia Rating Scale (BFMDRS) and Barry-Albright Dystonia Scale (BADS) scores between the baseline and 12-month assessments. Video documentation was used for blinded ratings. Secondary outcomes included evaluation of spasticity (Modified Ashworth Scale score), quality of life (Pediatric Quality of Life Inventory [PedsQL] and modified Unified Parkinson's Disease Rating Scale Part II [UPDRS-II] scores), and neuropsychological assessments. Adverse events were monitored for safety.

RESULTS

All participants tolerated the procedure well, and there were no safety concerns or serious adverse events. There was an average improvement of 21.5% in the BFMDRS motor subscale score, but the improvement was only 1.6% according to the BADS score. Following blinded video review, dystonia severity ratings were even more modest. Secondary outcomes, however, were more encouraging, with the BFMDRS disability subscale score improving by 15.7%, the PedsQL total score by 27%, and the modified UPDRS-II score by 19.3%. Neuropsychological assessment findings were unchanged 1 year after surgery.

CONCLUSIONS

Bilateral thalamic neuromodulation by DBS for severe, medication-refractory acquired dystonia was well tolerated. Primary and secondary outcomes showed highly variable treatment effect sizes comparable to those of pallidal stimulation in this population. As previously described, improvements in quality of life and disability were not reflected in dystonia severity scales, suggesting a need for the development of scales specifically for acquired dystonia.Clinical trial registration no.: NCT03078816 (clinicaltrials.gov).

Neurons under genetic control: What are the next steps towards the treatment of movement disorders?

Since the implementation of deep-brain stimulation as a therapy for movement disorders, there has been little progress in the clinical application of novel alternative treatments. Movement disorders are a group of neurological conditions, which are characterised with impairment of voluntary movement and share similar anatomical loci across the basal ganglia. The focus of the current review is on Parkinson's disease and Huntington's disease as they are the most investigated hypokinetic and hyperkinetic movement disorders, respectively. The last decade has seen enormous advances in the development of laboratory techniques that control neuronal activity. The two major ways to genetically control the neuronal function are: 1) expression of light-sensitive proteins that allow for the optogenetic control of the neuronal spiking and 2) expression or suppression of genes that control the transcription and translation of proteins. However, the translation of these methodologies from the laboratories into the clinics still faces significant challenges. The article summarizes the latest developments in optogenetics and gene therapy. Here, I compare the physiological mechanisms of established electrical deep brain stimulation to the experimental optogenetical deep brain stimulation. I compare also the advantages of DNA- and RNA-based techniques for gene therapy of familial movement disorders. I highlight the benefits and the major issues of each technique and I discuss the translational potential and clinical feasibility of optogenetic stimulation and gene expression control. The review emphasises recent technical breakthroughs that could initiate a notable leap in the treatment of movement disorders.

High Frequency Deep Brain Stimulation of Superior Cerebellar Peduncles in a Patient with Cerebral Palsy

Background

Globus pallidus internus (GPi) deep brain stimulation (DBS) is widely used in patients with isolated dystonia; however, its use remains controversial in patients with acquired dystonia and cerebral palsy.

Case presentation

We report the first case of a cerebral palsy patient, who failed to recover 2 years after GPi DBS; DBS was administered on both superior cerebellar peduncles (SCPs) and dentate nuclei (DNs). The monopolar stimulation results suggested that DBS was better administered via the SCPs than via the DNs. At six months follow-up, the patient exhibited a significant improvement of dystonia and spasticity, as well as in her quality of life.

Discussion

SCP DBS may be a potential treatment for cerebral palsy patients with dystonia and spasticity who do not respond well to GPi DBS.

Treatment of Disorders of Tone and Other Considerations in Pediatric Movement Disorders

Pediatric movement disorders (PMDs) consist of a heterogeneous group of signs and symptoms caused by numerous neurological diseases. Different neurological disorders in children also share overlapping movement disorders making a diagnosis of the underlying cause of the movement disorder challenging. The similarity of the symptoms across multiple disease types suggests that there may be a final common motor pathway causing the overlapping movement disorders. There are numerous disorders in children associated with disturbances in tone and involuntary movements. This chapter will focus primarily on those disorders that involve abnormalities of tone and other important considerations of pediatric movement disorders. This chapter will address rating scales and goals for treatment and will include a review of symptomatic treatment and, where possible, the treatment of the underlying disease processes. The chapter will review representative disorders, including an inborn error of metabolism, an autoimmune disorder, and a group of neurodegenerative disorders. These examples demonstrate how the disorder's underlying pathophysiology results in a specific approach to the underlying disease and the associated conditions of tone and involuntary movements. Finally, the multiple treatment options for cerebral palsy and considerations of cerebral palsy mimics will be discussed.

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.

Application of Machine Learning Using Decision Trees for Prognosis of Deep Brain Stimulation of Globus Pallidus Internus for Children With Dystonia

BACKGROUND

While Deep Brain Stimulation (DBS) of the Globus pallidus internus is a well-established therapy for idiopathic/genetic dystonia, benefits for acquired dystonia are varied, ranging from modest improvement to deterioration. Predictive biomarkers to aid DBS prognosis for children are lacking, especially in acquired dystonias, such as dystonic Cerebral Palsy. We explored the potential role of machine learning techniques to identify parameters that could help predict DBS outcome.

METHODS

We conducted a retrospective study of 244 children attending King's College Hospital between September 2007 and June 2018 for neurophysiological tests as part of their assessment for possible DBS at Evelina London Children's Hospital. For the 133 individuals who underwent DBS and had 1-year outcome data available, we assessed the potential predictive value of six patient parameters: sex, etiology (including cerebral palsy), baseline severity (Burke-Fahn-Marsden Dystonia Rating Scale-motor score), cranial MRI and two neurophysiological tests, Central Motor Conduction Time (CMCT) and Somatosensory Evoked Potential (SEP). We applied machine learning analysis to determine the best combination of these features to aid DBS prognosis. We developed a classification algorithm based on Decision Trees (DTs) with k-fold cross validation for independent testing. We analyzed all possible combinations of the six features and focused on acquired dystonias.

RESULTS

Several trees resulted in better accuracy than the majority class classifier. However, the two features that consistently appeared in top 10 DTs were CMCT and baseline dystonia severity. A decision tree based on CMCT and baseline severity provided a range of sensitivity and specificity, depending on the threshold chosen for baseline dystonia severity. In situations where CMCT was not available, a DT using SEP alone provided better than the majority class classifier accuracy.

CONCLUSION

The results suggest that neurophysiological parameters can help predict DBS outcomes, and DTs provide a data-driven, highly interpretable decision support tool that lends itself to being used in clinical practice to help predict potential benefit of DBS in dystonic children. Our results encourage the introduction of neurophysiological parameters in assessment pathways, and data collection to facilitate multi-center evaluation and validation of these potential predictive markers and of the illustrative decision support tools presented here.

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

Hyperpolarization of the subthalamic nucleus alleviates hyperkinetic movement disorders

Modulation of subthalamic nucleus (STN) firing patterns with injections of depolarizing currents into the STN is an important advance for the treatment of hypokinetic movement disorders, especially Parkinson’s disease (PD). Chorea, ballism and dystonia are prototypical examples of hyperkinetic movement disorders. In our previous study, normal rats without nigro-striatal lesion were rendered hypokinetic with hyperpolarizing currents injected into the STN. Therefore, modulation of the firing pattern by injection of a hyperpolarizing current into the STN could be an effective treatment for hyperkinetic movement disorders. We investigated the effect of injecting a hyperpolarizing current into the STNs of two different types of hyperkinetic animal models and a patient with an otherwise uncontrollable hyperkinetic disorder. The two animal models included levodopa-induced hyperkinetic movement in parkinsonian rats (L-DOPA-induced dyskinesia model) and hyperkinesia induced by an intrastriatal injection of 3-nitropropionic acid (Huntington disease model), covering neurodegeneration-related as well as neurotoxin-induced derangement in the cortico-subcortical re-entrant loops. Delivering hyperpolarizing currents into the STN readily alleviated the hyperkinetic behaviors in the two animal models and in the clinical case, with an evident increase in subthalamic burst discharges in electrophysiological recordings. Application of a hyperpolarizing current into the STN via a Deep brain stimulation (DBS) electrode could be an effective general therapy for a wide spectrum of hyperkinetic movement disorders.

A questionnaire survey on the efficacy of various treatments for dyskinetic cerebral palsy due to preterm bilirubin encephalopathy

OBJECTIVES

Preterm children with severe dyskinetic cerebral palsy due to bilirubin encephalopathy often suffer from marked generalised hypertonus as they age. We performed a questionnaire survey to investigate patient-reported outcomes of treatments for improving their activities of daily life.

METHODS

A mail questionnaire was administered to the caregivers of 67 children with preterm bilirubin encephalopathy aged >4 years. We asked about the type of treatments they received and their efficacy using a five-point subjective scale for the following five domains: motor function, postural stability, sleep, pain, and care burden. The names of oral drugs and their efficacies were also explored.

RESULTS

The response rate of the questionnaires was 62.7% (42/67), and we analysed the results from 41 validated cases. All children underwent rehabilitation. A total of 30 children received oral drugs, 22 botulinum toxin, 12 orthopaedic surgery, and 3 intrathecal baclofen. Each of these treatments was subjectively reported to be effective in more than half of the recipients for each of the five domains, whereas 23 (56%) required more than two types of treatments other than rehabilitation. Chlordiazepoxide was the most commonly used oral drug, by 28 children (68%), and was discontinued in 7 patients (25%) only. In the sleep domain, the rate of a positive effect was significantly higher for oral drugs (92.7%) than the other treatments (p < 0.01).

CONCLUSION

All treatments were partially effective, but their appropriate combination based on a multidisciplinary approach is essential for muscle tone management in children with preterm bilirubin encephalopathy.

Abnormal patterns of corticomuscular and intermuscular coherence in childhood dystonia

OBJECTIVE

Sensorimotor processing is abnormal in Idiopathic/Genetic dystonias, but poorly studied in Acquired dystonias. Beta-Corticomuscular coherence (CMC) quantifies coupling between oscillatory electroencephalogram (EEG) and electromyogram (EMG) activity and is modulated by sensory stimuli. We test the hypothesis that sensory modulation of CMC and intermuscular coherence (IMC) is abnormal in Idiopathic/Genetic and Acquired dystonias.

METHODS

Participants: 11 children with Acquired dystonia, 5 with Idiopathic/Genetic dystonia, 13 controls (12-18 years). CMC and IMC were recorded during a grasp task, with mechanical perturbations provided by an electromechanical tapper. Coherence patterns pre- and post-stimulus were compared across groups.

RESULTS

Beta-CMC increased post-stimulus in Controls and Acquired dystonia (p = 0.001 and p = 0.010, respectively), but not in Idiopathic/Genetic dystonia (p = 0.799). The modulation differed between groups, being larger in both Controls and Acquired dystonia compared with Idiopathic/Genetic dystonia (p = 0.003 and p = 0.022). Beta-IMC increased significantly post-stimulus in Controls (p = 0.004), but not in dystonia. Prominent 4-12 Hz IMC was seen in all dystonia patients and correlated with severity (rho = 0.618).

CONCLUSION

Idiopathic/Genetic and Acquired dystonia share an abnormal low-frequency IMC. In contrast, sensory modulation of beta-CMC differed between the two groups.

SIGNIFICANCE

The findings suggest that sensorimotor processing is abnormal in Acquired as well as Idiopathic/Genetic dystonia, but that the nature of the abnormality differs.

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

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

A systematic review on quality of life assessment in adults with cerebral palsy: Challenging issues and a call for research

BACKGROUND AND AIMS

Little is known about the quality of life (QoL) of adults with cerebral palsy (CP). This systematic review aimed to examine the extent to which methodological best practices have been applied to achieve valid and informative QoL assessments for this population.

METHODS AND PROCEDURES

Systematic search identified 1097 non-duplicated, quantitative articles assessing self- and/or proxy-reported QoL in samples of adults with CP. Eighteen studies were included and data extraction was conducted for sampling characteristics, selection of informants (self- and proxy-reports), adequacy of administered measures, and examination of age-related specificities.

OUTCOMES AND RESULTS

The results revealed discrepancies between conceptual definitions of QoL and their measurement approaches in CP. Most papers relied on self-reports. Most studies were cross-sectional and often based on relatively small samples; the variable of age was considered inconsistently in statistical analyses.

CONCLUSIONS AND IMPLICATIONS

Future strategies to improve the validity and applicability of QoL assessments of adults with CP would include: using a clear definition of QoL aligned with the measurement employed; considering proxy-reports whenever appropriate, to encompass larger samples and a wider range of ability; and using age-stratified analyses, in order to deepen understanding of potentially modifiable variables and paths linked to QoL outcomes.

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.

Botulinum Toxin in the Management of Children with Cerebral Palsy

During the past 25 years, botulinum toxin type A (BoNT-A) has become the most widely used medical intervention in children with cerebral palsy. In this review we consider the gaps in our knowledge in the use of BoNT-A and reasons why muscle morphology and function in children with cerebral palsy are impaired. We review limitations in our knowledge regarding the mechanisms underlying the development of contractures and the difficulty in preventing them. It is clear from this review that injection of BoNT-A in the large muscles of both the upper and lower limbs of children with cerebral palsy will result in a predictable decrease in muscle activity, which is usually reported as a reduction in spasticity, for between 3 and 6 months. These changes are noted by the use of clinical tools such as the Modified Ashworth Scale and the Modified Tardieu Scale. Decreased muscle over-activity usually results in improved range of motion in distal joints. Injection of the gastrocnemius muscle for toe-walking in a child with hemiplegia or diplegia usually has the effect of increasing the passive range of dorsiflexion at the ankle. In our review, we found that this may result in a measurable improvement in gait by the use of observational gait scales or gait analysis, in some children. However, improvements in gait function are not always achieved and are small in magnitude and short lived. We found that some of the differences in outcomes in clinical trials may relate to the use of adjunctive interventions such as serial casting, orthoses, night splints and intensive therapy. We note that the majority of clinical trials of the use of BoNT-A in children with cerebral palsy have focussed on a single injection cycle and this is insufficient to understand the balance between benefit and harm. Most outcomes were reported in terms of changes in muscle tone and there were fewer studies with robust methodology that reported improvements in function. Changes in the domains of activities and participation have rarely been reported in studies to date. There were no clinical reviews to date that consider the findings of studies in human volunteers and in experimental animals and their relevance to clinical protocols. In this review we found that studies in human volunteers and in experimental animals show muscle atrophy after an injection of BoNT-A for at least 12 months. Muscle atrophy was accompanied by loss of contractile elements in muscle and replacement with fat and connective tissue. It is not currently known if these changes, mediated at a molecular level, are reversible. We conclude that there is a need to revise clinical protocols by using BoNT-A more thoughtfully, less frequently and with greatly enhanced monitoring of the effects on injected muscle for both short-term and long-term benefits and harms.