Deep brain stimulation in pediatric dystonia: a systematic review

Spiking activities in small neural networks induced by external forcing

Neurons in an excitable mode do not show spiking activity and, therefore, do not contribute to information transfer transmission and its processing. However, some external influences, coupling, or time delay can lead to the appearance of oscillations in individual systems or networks. The main goal of this paper is to uncover the connection parameters and parameters of external influences that lead to the arising of spiking behavior in a small network of locally coupled FitzHugh-Nagumo oscillators. In this study, we analyze the dynamics of a small network in the absence and presence of several types of external influences. First, we consider the impact of periodic-pulse exposure generated as a periodic sequence of Gaussian pulses. Second, we show what behavior can be induced by far less regular pulsed influence (Lévy noise) and its special case called white Gaussian noise. For all types of influences, we have identified the appropriate parameters (local coupling strength, intensity, and frequency) that induce spiking activity in the small network.

Deep Brain Stimulation for Childhood Treatment-Resistant Obsessive-Compulsive Disorder: Mental Health Clinician Views on Candidacy Factors

INTRODUCTION

Deep brain stimulation (DBS) is approved under a humanitarian device exemption to manage treatment-resistant obsessive-compulsive disorder (TR-OCD) in adults. It is possible that DBS may be trialed or used clinically off-label in children and adolescents with TR-OCD in the future. DBS is already used to manage treatment-resistant childhood dystonia. Evidence suggests it is a safe and effective intervention for certain types of dystonia. Important questions remain unanswered about the use of DBS in children and adolescents with TR-OCD, including whether mental health clinicians would refer pediatric patients for DBS, and who would be a good candidate for DBS.

OBJECTIVES

To explore mental health clinicians' views on what clinical and psychosocial factors they would consider when determining which children with OCD would be good DBS candidates.

MATERIALS AND METHODS

In depth, semi-structured interviews were conducted with n = 25 mental health clinicians who treat pediatric patients with OCD. The interviews were transcribed, coded, and analyzed using thematic content analysis. Three questions focused on key, clinical, and psychosocial factors for assessing candidacy were analyzed to explore respondent views on candidacy factors. Our analysis details nine overarching themes expressed by clinicians, namely the patient's previous OCD treatment, OCD severity, motivation to commit to treatment, presence of comorbid conditions, family environment, education on DBS, quality of life, accessibility to treatment, and patient age and maturity.

CONCLUSIONS

Clinicians generally saw considering DBS treatment in youth as a last resort and only for very specific cases. DBS referral was predominantly viewed as acceptable for children with severe TR-OCD who have undertaken intensive, appropriate treatment without success, whose OCD has significantly reduced their quality of life, and who exhibit strong motivation to continue treatment given the right environment. Appropriate safeguards, eligibility criteria, and procedures should be discussed and identified before DBS for childhood TR-OCD becomes practice.

Content and readability of patient educational materials about neuromodulation for childhood movement disorders

PURPOSE

To assess content and readability of online patient educational materials (PEMs) for paediatric deep brain stimulation (DBS) and intrathecal baclofen (ITB).

METHODS

A content analysis of PEMs identified from top children's hospitals, institutions affiliated with published neuromodulation research, and DBS and ITB device manufacturers was conducted. PEM content was analysed using a predetermined framework. Readability was assessed using the Simple Measure of Gobbledygook (SMOG).

RESULTS

Of 109 PEMs (72 DBS; 37 ITB) identified, most (77 (71%)) originated in the United States. More ITB PEMs (27 (73%)) contained specific paediatric information than DBS PEMs (16 (22%)). PEMS more frequently described benefits (DBS: 92%; ITB: 89%) than risks (DBS: 49%; ITB: 78%). Frequent content included pre- and post-operative care, procedural details, and device information. Less common content included long-term lifestyle considerations, alternatives, patient experiences, and financial details. Median readability of PEMs was 13.2 (interquartile range [IQR]: 11.4-14.45) for DBS and 11.8 (IQR: 11-12.9) for ITB.

CONCLUSIONS

Available ITB and DBS PEMs often miss important broader details of the treatments, and have additional shortcomings such as poor readability scores. Our findings highlight need for more holistic content within neuromodulation PEMs, improved accessibility, and more balanced representation of risks and benefits.

Impact of pulse exposure on chimera state in ensemble of FitzHugh-Nagumo systems

In this article, we consider the influence of a periodic sequence of Gaussian pulses on a chimera state in a ring of coupled FitzHugh-Nagumo systems. We found that on the way to complete spatial synchronization, one can observe a number of variations of chimera states that are not typical for the parameter range under consideration. For example, the following modes were found: breathing chimera, chimera with intermittency in the incoherent part, traveling chimera with strong intermittency, and others. For comparison, here we also consider the impact of a harmonic influence on the same chimera, and to preserve the generality of the conclusions, we compare the regimes caused by both a purely positive harmonic influence and a positive-negative one.

Long-Term Globus Pallidus Internus Deep Brain Stimulation in Pediatric Non-Degenerative Dystonia: A Cohort Study and a Meta-Analysis

BACKGROUND

The evidence in the effectiveness of deep brain stimulation in children with medication-refractory non-degenerative monogenic dystonia is heterogeneous and long-term results are sparse.

OBJECTIVES

The objective is to describe long-term outcomes in a single-center cohort and compare our results with a meta-analysis cohort form literature.

METHODS

We performed a retrospective single-center cohort study including consecutive pediatric patients with non-degenerative genetic or idiopathic dystonia treated with globus pallidus internus deep brain stimulation at our center and a systematic review and individual-patient data meta-analysis with the same inclusion criteria. The primary outcome was the change from baseline in the Burke-Fahn-Marsden Dystonia Rating Scale-movement (BFMDRS-M) score.

RESULTS

The clinical cohort included 25 patients with a mean study follow-up of 11.4 years. The meta-analysis cohort included 224 patients with a mean follow-up of 3 years. Overall, the BFMDRS-M mean improvements at 1 year and at last follow-up were 41% and 33% in the clinical cohort and 58.9% and 57.2% in the meta-analysis cohort, respectively. TOR1A-dystonia showed the greatest and most stable BFMDRS-M improvement in both cohorts at 1 year and at last follow-up (76.3% and 74.3% in the clinical cohort; 69.6% and 67.3% in the meta-analysis cohort), followed by SGCE-dystonia (63% and 63.9% in the meta-analysis cohort). THAP1-dystonia (70.1% and 29.8% in the clinical cohort; 52.3% and 42.0% in the meta-analysis cohort) and KMT2B-dystonia (33.3% and 41.3% in the clinical cohort; 38.0% and 26.7% in the meta-analysis cohort) showed a less pronounced or sustained response.

CONCLUSION

Globus pallidus deep brain stimulation long-term treatment seems effective with a possible gene-specific differential effect. © 2024 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.

Neurosurgical and pharmacological management of dystonia

Dystonia characterizes a group of neurological movement disorders characterized by abnormal muscle movements, often with repetitive or sustained contraction resulting in abnormal posturing. Different types of dystonia present based on the affected body regions and play a prominent role in determining the potential efficacy of a given intervention. For most patients afflicted with these disorders, an exact cause is rarely identified, so treatment mainly focuses on symptomatic alleviation. Pharmacological agents, such as oral anticholinergic administration and botulinum toxin injection, play a major role in the initial treatment of patients. In more severe and/or refractory cases, focal areas for neurosurgical intervention are identified and targeted to improve quality of life. Deep brain stimulation (DBS) targets these anatomical locations to minimize dystonia symptoms. Surgical ablation procedures and peripheral denervation surgeries also offer potential treatment to patients who do not respond to DBS. These management options grant providers and patients the ability to weigh the benefits and risks for each individual patient profile. This review article explores these pharmacological and neurosurgical management modalities for dystonia, providing a comprehensive assessment of each of their benefits and shortcomings.

Deep Brain Stimulation of the Globus Pallidus Internus in a Child with Refractory Dystonia due to L2-Hydroxyglutaric Aciduria

INTRODUCTION

L-2-hydroxyglutaric aciduria (L2HGA) is a rare neurometabolic disorder marked by progressive and debilitating psychomotor deficits. Here, we report the first patient with L2HGA-related refractory dystonia that was managed with deep brain stimulation to the bilateral globus pallidus internus (GPi-DBS).

CASE PRESENTATION

We present a 17-year-old female with progressive decline in cognitive function, motor skills, and language ability which significantly impaired activities of daily living. Neurological exam revealed generalized dystonia, significant choreic movements in the upper extremities, slurred speech, bilateral dysmetria, and a wide-based gait. Brisk deep tendon reflexes, clonus, and bilateral Babinski signs were present. Urine 2-OH-glutaric acid level was significantly elevated. Brain MRI showed extensive supratentorial subcortical white matter signal abnormalities predominantly involving the U fibers and bilateral basal ganglia. Genetic testing identified a homozygous pathogenic mutation in the L-2-hydroxyglutarate dehydrogenase gene c. 164G>A (p. Gly55Asp). Following minimal response to pharmacotherapy, GPi-DBS was performed. Significant increases in mobility and decrease in dystonia were observed at 3 weeks, 6 months, and 12 months postoperatively.

CONCLUSION

This is the first utilization of DBS as treatment for L2HGA-related dystonia. The resulting significant improvements indicate that pallidal neuromodulation may be a viable option for pharmaco-resistant cases, and possibly in other secondary metabolic dystonias.

Quantitative analysis of noninvasive deep temporal interference stimulation: A simulation and experimental study

Background

Deep brain stimulation (DBS) is a method for stimulating deep regions of the brain for the treatment of various neurological and psychiatric disorders such as depression, obsessive-compulsive disorder, addiction, and Parkinson's disease. Generally, DBS can be performed using both invasive and non-invasive approaches. Invasive DBS is associated with several problems, including intracranial bleeding, infection, and changes in the position of the electrode tip. Temporal interference (TI) stimulation is a non-invasive technique used to stimulate deep regions of the brain by applying two high-frequency sinusoidal currents with slightly different frequencies.

New method

This paper presents insights into the response of the spiking in the Hodgkin-Huxley (HH) neuron model of the rat somatosensory cortex by changing the parameters carrier frequency, current ratio, and difference frequency of TI stimulation. Furthermore, in order to experimentally evaluate the effect of TI stimulation on the activation of the left motor cortex, an experiment was conducted to measure the motion induced by the balanced and unbalanced TI stimulation. In the experiment, a three-axis accelerometer was attached to the right hand of the animal to determine the position of the hand.

Results

Simulation results of the HH model showed that the frequency of the envelope of the TI stimulation is identical to the fundamental frequency of the neuron spikes. This result was obtained for difference frequencies of 6 Hz and 9 Hz in balanced and unbalanced TI stimulations. Moreover specifically, when the difference frequency is set to zero, the carrier frequency is within the range of 1300-1400 Hz, and the current range is between 140 and 250 μA/cm2, the firing rate reached to its highest value. In the experimental result, the maximum range of movement at a difference frequency of Δf = 6 Hz was approximately 1.6 mm and 5.3 mm in the z and y directions respectively.

Comparison with existing method

The results of the spatial spectrum of the rat hand movement were consistent with the spectrum information of the simulation results. Additionally, steering the interfering region to the left motor cortex leads to noticeable contralateral movement of the right hand while no movement was observed in the right hand during the stimulation of the right motor cortex.

Conclusion

This technique of stimulation for the deep regions of the brain is a promising tool to noninvasively treat various neurological and psychiatric disorders such as morphine dependence in addicted rats.

Adolescent OCD Patient and Caregiver Perspectives on Identity, Authenticity, and Normalcy in Potential Deep Brain Stimulation Treatment

The ongoing debate within neuroethics concerning the degree to which neuromodulation such as deep brain stimulation (DBS) changes the personality, identity, and agency (PIA) of patients has paid relatively little attention to the perspectives of prospective patients. Even less attention has been given to pediatric populations. To understand patients' views about identity changes due to DBS in obsessive-compulsive disorder (OCD), the authors conducted and analyzed semistructured interviews with adolescent patients with OCD and their parents/caregivers. Patients were asked about projected impacts to PIA generally due to DBS. All patient respondents and half of caregivers reported that DBS would impact patient self-identity in significant ways. For example, many patients expressed how DBS could positively impact identity by allowing them to explore their identities free from OCD. Others voiced concerns that DBS-related resolution of OCD might negatively impact patient agency and authenticity. Half of patients expressed that DBS may positively facilitate social access through relieving symptoms, while half indicated that DBS could increase social stigma. These views give insights into how to approach decision-making and informed consent if DBS for OCD becomes available for adolescents. They also offer insights into adolescent experiences of disability identity and "normalcy" in the context of OCD.

Deep brain stimulation in pediatric dystonia: calls for therapeutic realism over nihilism

PURPOSE

Pediatric dystonia (PD) has a significant negative impact on the growth and development of the child. This study was done retrospectively to analyze functional outcomes in pediatric patients with dystonia who underwent deep brain stimulation.

METHODS

In this retrospective analytical study, all the patients of age less than 18 years undergoing deep brain stimulation (DBS) for dystonia between 2012 and 2020 in a single center were analyzed and their functional outcomes were measured by the Burke-Fahn-Marsden-dystonia-rating-scale (BFMDRS).

RESULTS

A total of 10 pediatric patients were included with a mean age of onset, duration of disease, and age at surgery being 5.75 years, 7.36 years, and 13.11 years, respectively, with a mean follow-up of 23.22 months. The mean pre-DBS motor score was 75.44 ± 23.53 which improved significantly at 6-month and 12-month follow-up to 57.27 (p value 0.004) and 50.38 (p value < 0.001), respectively. Limbs sub-scores improved significantly at both the scheduled intervals. There was a significant improvement in disability at 1-year follow-up with significant improvement in feeding, dressing, and walking components. There was a 27.34% and 36.64% improvement in dystonia with a 17.37% and 28.86% reduction in disability at 6 months and 12 months, respectively. There was a positive correlation between the absolute reduction of the motor score and improvement in disability of the patients at 6 months (rho = 0.865, p value 0.003).

CONCLUSIONS

DBS in PD has an enormous role in reducing disease burden and achieving a sustainable therapeutic goal.

MRI-Guided Focused Ultrasound for the Treatment of Dystonia: A Narrative Review

Contemporary surgical management of dystonia includes neuromodulation via deep brain stimulation (DBS) or ablative techniques such as radiofrequency (RF) ablation. MRI-guided focused ultrasound (MRgFUS) is an emerging modality that uses high-intensity ultrasound to precisely ablate targets in the brain; this is incisionless, potentially avoiding the surgical risks of a burr hole and transcortical tract to reach the anatomical target. There is some evidence of efficacy in essential tremor and Parkinson's disease (PD), but, to date, there is no study aggregating the evidence of MRgFUS in dystonia. In this narrative review, we searched Medline, Embase, CINAHL, EBSCO, and ClinicalTrials.gov for primary studies and clinical trials on MRgFUS in the treatment of dystonia. Data were analyzed concerning dystonia phenotype, reported outcomes, and complications. PD-related dystonia was also included within the scope of the review. Using our search criteria, six articles on the use of MRgFUS in adult dystonia and three articles on the use of FUS in dystonia in PD were included. Four trials on the use of FUS in dystonia were also found on ClinicalTrials.gov, one of which was completed in December 2013. All included studies showed evidence of symptomatic improvement, mostly in focal hand dystonia; improvements were also found in dystonia-associated tremor, cervicobrachial dystonia, and dystonia-associated chronic neuropathic pain as well as PD-related dystonia. Reported complications included transient neurological deficits and persistent arm pain in one study. However, the evidence is limited to level-4 case series at present. MRgFUS is an emerging modality that appears to be safe and effective, particularly in focal hand dystonia, without major adverse effects. However, the quality of evidence is low at present, and long-term outcomes are unknown. High-quality prospective studies comparing MRgFUS to other surgical techniques will be useful in determining its role in the management of dystonia.

Application of deep brain stimulation for the treatment of childhood-onset dystonia in patients with MEPAN syndrome

Introduction

Mitochondrial Enoyl CoA Reductase Protein-Associated Neurodegeneration (MEPAN) syndrome is a rare inherited metabolic condition caused by MECR gene mutations. This gene encodes a protein essential for fatty acid synthesis, and defects cause progressively worsening childhood-onset dystonia, optic atrophy, and basal ganglia abnormalities. Deep brain stimulation (DBS) has shown mixed improvement in other childhood-onset dystonia conditions. To the best of our knowledge, DBS has not been investigated as a treatment for dystonia in patients with MEPAN syndrome.

Methods

Two children with MEPAN were identified as possible DBS candidates due to severe generalized dystonia unresponsive to pharmacotherapy. Temporary depth electrodes were placed in six locations bilaterally and tested during a 6-day hospitalization to determine the best locations for permanent electrode placement. The Burke-Fahn-Marsden Dystonia Rating Scale (BFMDRS) and Barry-Albright Dystonia Scale (BADS) were used for preoperative and postoperative testing to quantitatively assess dystonia severity changes. Patient 1 had permanent electrodes placed at the globus pallidus internus (GPi) and pedunculopontine nucleus (PPN). Patient 2 had permanent electrodes placed at the GPi and ventralis intermedius nucleus of the thalamus (VIM).

Results

Both patients successfully underwent DBS placement with no perioperative complications and significant improvement in their BFMDRS score. Patient 2 also demonstrated improvement in the BADS.

Discussion

We demonstrated a novel application of DBS in MEPAN syndrome patients with childhood-onset dystonia. These patients showed clinically significant improvements in dystonia following DBS, indicating that DBS can be considered for dystonia in patients with rare metabolic disorders that currently have no other proven treatment options.

Stereotactic Awake Basal Ganglia Electrophysiological Recording and Stimulation (SABERS): A Novel Staged Procedure for Personalized Targeting of Deep Brain Stimulation in Pediatric Movement and Neuropsychiatric Disorders

Selection of targets for deep brain stimulation (DBS) has been based on clinical experience, but inconsistent and unpredictable outcomes have limited its use in patients with heterogeneous or rare disorders. In this large case series, a novel staged procedure for neurophysiological assessment from 8 to 12 temporary depth electrodes is used to select targets for neuromodulation that are tailored to each patient's functional needs. Thirty children and young adults underwent deep brain stimulation target evaluation with the new procedure: Stereotactic Awake Basal ganglia Electrophysiological Recording and Stimulation (SABERS). Testing is performed in an inpatient neuromodulation monitoring unit over 5-7 days, and results guide the decision to proceed and the choice of targets for permanent deep brain stimulation implantation. Results were evaluated 3-6 months postoperatively with the Burke-Fahn-Marsden Dystonia Rating Scale and the Barry-Albright Dystonia Scale. Stereotactic Awake Basal ganglia Electrophysiological Recording and Stimulation testing allowed modulation to be tailored to specific neurologic deficits in a heterogeneous population, including subjects with primary dystonia, secondary dystonia, and Tourette syndrome. All but one subject were implanted with 4 permanent deep brain stimulation leads. Results showed significant improvement on both scales at postoperative follow-up. No significant adverse events occurred. Use of the Stereotactic Awake Basal ganglia Electrophysiological Recording and Stimulation protocol with evaluation in the neuromodulation monitoring unit is feasible and results in significant patient benefit compared with previously published results in these populations. This new technique supports a significant expansion of functional neurosurgery to predict effective stimulation targets in a wide range of disorders of brain function, including those for which the optimal target is not yet known.

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.

Hope and Optimism in Pediatric Deep Brain Stimulation: Key Stakeholder Perspectives

Introduction

Deep brain stimulation (DBS) is utilized to treat pediatric refractory dystonia and its use in pediatric patients is expected to grow. One important question concerns the impact of hope and unrealistic optimism on decision-making, especially in "last resort" intervention scenarios such as DBS for refractory conditions.

Objective

This study examined stakeholder experiences and perspectives on hope and unrealistic optimism in the context of decision-making about DBS for childhood dystonia and provides insights for clinicians seeking to implement effective communication strategies.

Materials and Methods

Semi-structured interviews with clinicians (n = 29) and caregivers (n = 44) were conducted, transcribed, and coded.

Results

Using thematic content analysis, four major themes from clinician interviews and five major themes from caregiver interviews related to hopes and expectations were identified. Clinicians expressed concerns about caregiver false hopes (86%, 25/29) and desperation (68.9%, 20/29) in light of DBS being a last resort. As a result, 68.9% of clinicians (20/29) expressed that they intentionally tried to lower caregiver expectations about DBS outcomes. Clinicians also expressed concern that, on the flip side, unrealistic pessimism drives away some patients who might otherwise benefit from DBS (34.5%, 10/29). Caregivers viewed DBS as the last option that they had to try (61.3%, 27/44), and 73% of caregivers (32/44) viewed themselves as having high hopes but reasonable expectations. Fewer than half (43%, 19/44) expressed that they struggled setting outcome expectations due to the uncertainty of DBS, and 50% of post-DBS caregivers (14/28) expressed some negative feelings post treatment due to unmet expectations. 43% of caregivers (19/44) had experiences with clinicians who tried to set low expectations about the potential benefits of DBS.

Conclusion

Thoughtful clinician-stakeholder discussion is needed to ensure realistic outcome expectations.

Neurosurgical management of non-spastic movement disorders

BACKGROUND

Non-spastic movement disorders in children are common, although true epidemiologic data is difficult to ascertain. Children are more likely than adults to have hyperkinetic movement disorders defined as tics, dystonia, chorea/athetosis, or tremor. These conditions manifest from acquired or heredodegenerative etiologies and often severely limit function despite medical and surgical management paradigms. Neurosurgical management for these conditions is highlighted.

METHODS

We performed a focused review of the literature by searching PubMed on 16 May 2023 using key terms related to our review. No temporal filter was applied, but only English articles were considered. We searched for the terms (("Pallidotomy"[Mesh]) OR "Rhizotomy"[Mesh]) OR "Deep Brain Stimulation"[Mesh], dystonia, children, adolescent, pediatric, globus pallidus, in combination. All articles were reviewed for inclusion in the final reference list.

RESULTS

Our search terms returned 37 articles from 2004 to 2023. Articles covering deep brain stimulation were the most common (n = 34) followed by pallidotomy (n = 3); there were no articles on rhizotomy.

DISCUSSION

Non-spastic movement disorders are common in children and difficult to treat. Most of these patients are referred to neurosurgery for the management of dystonia, with modern neurosurgical management including pallidotomy, rhizotomy, and deep brain stimulation. Historically, pallidotomy has been effective and may still be preferred in subpopulations presenting either in status dystonicus or with high risk for hardware complications. Superiority of DBS over pallidotomy for secondary dystonia has not been determined. Rhizotomy is an underutilized surgical tool and more study characterizing efficacy and risk profile is indicated.

Deep Brain Stimulation for Pediatric Dystonia: Clinicians' Perspectives on the Most Pressing Ethical Challenges

INTRODUCTION

Pediatric deep brain stimulation (pDBS) is commonly used to manage treatment-resistant primary dystonias with favorable results and more frequently used for secondary dystonia to improve quality of life. There has been little systematic empirical neuroethics research to identify ethical challenges and potential solutions to ensure responsible use of DBS in pediatric populations.

METHODS

Clinicians (n = 29) who care for minors with treatment-resistant dystonia were interviewed for their perspectives on the most pressing ethical issues in pDBS.

RESULTS

Using thematic content analysis to explore salient themes, clinicians identified four pressing concerns: (1) uncertainty about risks and benefits of pDBS (22/29; 72%) that poses a challenge to informed decision-making; (2) ethically navigating decision-making roles (15/29; 52%), including how best to integrate perspectives from diverse stakeholders (patient, caregiver, clinician) and how to manage surrogate decisions on behalf of pediatric patients with limited capacity to make autonomous decisions; (3) information scarcity effects on informed consent and decision quality (15/29; 52%) in the context of patient and caregivers' expectations for treatment; and (4) narrow regulatory status and access (7/29; 24%) such as the lack of FDA-approved indications that contribute to decision-making uncertainty and liability and potentially limit access to DBS among patients who may benefit from it.

CONCLUSION

These results suggest that clinicians are primarily concerned about ethical limitations of making difficult decisions in the absence of informational, regulatory, and financial supports. We discuss two solutions already underway, including supported decision-making to address uncertainty and further data sharing to enhance clinical knowledge and discovery.

Single-Electrode Deep Brain Stimulation of Bilateral Posterolateral Globus Pallidus Internus in Patients With Medically Resistant Lesch-Nyhan Syndrome

Deep brain stimulation (DBS) targeting various locations within the globus pallidus internus (GPi) is emerging as a therapeutic option for patients with medically resistant Lesch-Nyhan syndrome. We report our institutional experience with single-electrode DBS in the bilateral posterolateral GPi as an effective method for reduction of both dystonia and self-injurious behavior. Two pediatric patients aged six and 14 years underwent implantation of bilateral singular DBS leads in the posterolateral GPi and were followed postoperatively through the programming process and symptomatic improvements. Caregivers reported that after DBS in the posterolateral GPi, these patients experienced decreased self-mutilation behavior and decreased dystonia.

Elective and Emergency Deep Brain Stimulation in Refractory Pediatric Monogenetic Movement Disorders Presenting with Dystonia: Current Practice Illustrated by Two Cases

BACKGROUND

Dystonia is characterized by sustained or intermittent muscle contractions, leading to abnormal posturing and twisting movements. In pediatric patients, dystonia often negatively influences quality of life. Pharmacological treatment for dystonia is often inadequate and causes adverse effects. Deep brain stimulation (DBS) appears to be a valid therapeutic option for pharmacoresistant dystonia in children.

METHODS

To illustrate the current clinical practice, we hereby describe two pediatric cases of monogenetic movement disorders presenting with dystonia and treated with DBS. We provide a literature review of similar previously described cases and on different clinical aspects of DBS in pediatric dystonia.

RESULTS

The first patient, a 6-year-old girl with severe dystonia, chorea, and myoclonus due to an ADCY5 gene mutation, received DBS in an elective setting. The second patient, an 8-year-old boy with GNAO1-related dystonia and chorea, underwent emergency DBS due to a pharmacoresistant status dystonicus. A significant amelioration of motor symptoms (65% on the Burke-Fahn-Marsden Dystonia Rating Scale) was observed postoperatively in the first patient and her personal therapeutic goals were achieved. DBS was previously reported in five patients with ADCY5-related movement disorders, of which three showed objective improvement. Emergency DBS in our second patient resulted in the successful termination of his GNAO1-related status dystonicus, this being the eighth case reported in the literature.

CONCLUSION

DBS can be effective in monogenetic pediatric dystonia and should be considered early in the disease course. To better evaluate the effects of DBS on patients' functioning, patient-centered therapeutic goals should be discussed in a multidisciplinary approach.

Long-Term Outcomes of Deep Brain Stimulation for Pediatric Dystonia

BACKGROUND

Deep brain stimulation (DBS) has been utilized for over two decades to treat medication-refractory dystonia in children. Short-term benefit has been demonstrated for inherited, isolated, and idiopathic cases, with less efficacy in heredodegenerative and acquired dystonia. The ongoing publication of long-term outcomes warrants a critical assessment of available information as pediatric patients are expected to live most of their lives with these implants.

SUMMARY

We performed a review of the literature for data describing motor and neuropsychiatric outcomes, in addition to complications, 5 or more years after DBS placement in patients undergoing DBS surgery for dystonia at an age younger than 21. We identified 20 articles including individual data on long-term motor outcomes after DBS for a total of 78 patients. In addition, we found five articles reporting long-term outcomes after DBS in 9 patients with status dystonicus. Most patients were implanted within the globus pallidus internus, with only a few cases targeting the subthalamic nucleus and ventrolateral posterior nucleus of the thalamus. The average follow-up was 8.5 years, with a range of up to 22 years. Long-term outcomes showed a sustained motor benefit, with median Burke-Fahn-Marsden dystonia rating score improvement ranging from 2.5% to 93.2% in different dystonia subtypes. Patients with inherited, isolated, and idiopathic dystonias had greater improvement than those with heredodegenerative and acquired dystonias. Sustained improvements in quality of life were also reported, without the development of significant cognitive or psychiatric comorbidities. Late adverse events tended to be hardware-related, with minimal stimulation-induced effects.

KEY MESSAGES

While data regarding long-term outcomes is somewhat limited, particularly with regards to neuropsychiatric outcomes and adverse events, improvement in motor outcomes appears to be preserved more than 5 years after DBS placement.

Starting a DBS service for children: It's not the latitude but the attitude - Establishment of the paediatric DBS centre in Northern Finland

OBJECTIVE

Paediatric movement disorder patients can benefit from deep brain stimulation (DBS) treatment and it should be offered in a timely manner. In this paper we describe our experience establishing a DBS service for paediatric patients.

METHODS

We set out to establish a paediatric DBS (pDBS) procedure in Oulu University Hospital in northern Finland, where up to this point DBS treatment for movement disorders had been available for adult patients. Collaboration with experienced centres aided in the process.

RESULTS

A multidisciplinary team was assembled and a systematic protocol for patient evaluation and treatment was created, with attention to special features of the regional health care system. All of our first paediatric patients had very severe movement disorders, which is typical for a new DBS centre. The patients benefitted from pDBS treatment despite variable aetiologies of movement disorders, which included cerebral palsy and rare genetic disorders with variants in PDE10A, TPK1 and ARX. We also present our high-quality paediatric MR-imaging protocol with tractography.

CONCLUSIONS

Establishment of a pDBS centre requires expertise in classification of paediatric movement disorders, longstanding experience in adult DBS and a committed multidisciplinary team. Besides high-quality imaging and a skilled neurosurgery team, careful patient selection, realistic treatment goals and experience in rehabilitation are imperative in pDBS treatment.

Pressing ethical issues in considering pediatric deep brain stimulation for obsessive-compulsive disorder

BACKGROUND

Refractory obsessive-compulsive disorder (OCD) among adults is the first psychiatric indication of deep brain stimulation (DBS) to receive an FDA Humanitarian Device Exemption (HDE). Given the HDE approval and encouraging evidence that has since emerged, exploration of DBS for OCD may expand to adolescents in the future. More than 100,000 adolescents in the U.S. suffer from refractory OCD, and there is already a precedent for the transition of DBS in adults to children in the case of dystonia. However, the risk-benefit analysis of pediatric DBS for OCD may be more complex and raise different ethical questions compared to pediatric DBS for dystonia.

OBJECTIVE

This study aimed to gain insight into pressing ethical issues related to using DBS in adolescents with OCD.

METHODS

Semi-structured interviews were conducted with clinicians (n = 25) caring for pediatric patients with refractory OCD. Interview transcripts were coded with MAXQDA 2018 software and analyzed using thematic content analysis to identify emergent themes.

RESULTS

Five central themes were identified in clinician responses, three of which were exacerbated in the pediatric DBS setting. Clinicians expressed concerns related to conditions of decision-making including adolescents' capacity to assent (80%), the lack of evidence about the outcomes and potential unknown effects of using DBS in adolescents with OCD (68%), and the importance of exhausting other treatment options before considering DBS (20%).

CONCLUSIONS

Strategies to address clinician concerns include implementation of validated decision support tools and further research into the outcomes of pediatric DBS for OCD to establish clear guidelines for patient selection.

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.

Targeting accuracy of robot-assisted deep brain stimulation surgery in childhood-onset dystonia: a single-center prospective cohort analysis of 45 consecutive cases

OBJECTIVE

Deep brain stimulation (DBS) is an established treatment for pediatric dystonia. The accuracy of electrode implantation is multifactorial and remains a challenge in this age group, mainly due to smaller anatomical targets in very young patients compared to adults, and also due to anatomical abnormalities frequently associated with some etiologies of dystonia. Data on the accuracy of robot-assisted DBS surgery in children are limited. The aim of the current paper was to assess the accuracy of robot-assisted implantation of DBS leads in a series of patients with childhood-onset dystonia.

METHODS

Forty-five children with dystonia undergoing implantation of DBS leads under general anesthesia between 2017 and 2019 were included. Robot-assisted stereotactic implantation of the DBS leads was performed. The final position of the electrodes was verified with an intraoperative 3D scanner (O-arm). Coordinates of the planned electrode target and actual electrode position were obtained and compared, looking at the radial error, depth error, absolute error, and directional error, as well as the euclidean distance. Functional assessment data prospectively collected by a multidisciplinary pediatric complex motor disorders team were analyzed with regard to motor skills, individualized goal achievement, and patients' and caregivers' expectations.

RESULTS

A total of 90 DBS electrodes were implanted and 48.5% of the patients were female. The mean age was 11.0 ± 0.6 years (range 3-18 years). All patients received bilateral DBS electrodes into the globus pallidus internus. The median absolute errors in x-, y-, and z-axes were 0.85 mm (range 0.00-3.25 mm), 0.75 mm (range 0.05-2.45 mm), and 0.75 mm (range 0.00-3.50 mm), respectively. The median euclidean distance from the target to the actual electrode position was 1.69 ± 0.92 mm, and the median radial error was 1.21 ± 0.79. The robot-assisted technique was easily integrated into the authors' surgical practice, improving accuracy and efficiency, and reducing surgical time significantly along the learning curve. No major perioperative complications occurred.

CONCLUSIONS

Robot-assisted stereotactic implantation of DBS electrodes in the pediatric age group is a safe and accurate surgical method. Greater accuracy was present in this cohort in comparison to previous studies in which conventional stereotactic frame-based techniques were used. Robotic DBS surgery and neuroradiological advances may result in further improvement in surgical targeting and, consequently, in better clinical outcome in the pediatric population.

Arching deep brain stimulation in dystonia types

Although medical treatment including botulinum toxic injection is the first-line treatment for dystonia, response is insufficient in many patients. In these patients, deep brain stimulation (DBS) can provide significant clinical improvement. Mounting evidence indicates that DBS is an effective and safe treatment for dystonia, especially for idiopathic and inherited isolated generalized/segmental dystonia, including DYT-TOR1A. Other inherited dystonia and acquired dystonia also respond to DBS to varying degrees. For Meige syndrome (craniofacial dystonia), other focal dystonia, and some rare inherited dystonia, further evidences are still needed to evaluate the role of DBS. Because short disease duration at DBS surgery and absence of fixed musculoskeletal deformity are associated with better outcome, DBS should be considered as early as possible when indicated after careful evaluation including genetic work-up. This review will focus on the factors to be considered in DBS for patients with dystonia and the outcome of DBS in the different types of dystonia.

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.

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.

Long term follow-up results of deep brain stimulation of the Globus pallidus interna in pediatric patients with DYT1-positive dystonia

OBJECTIVES

Primary generalized dystonia (PGD) due to heterozygous torsin 1A (TOR1A) gene mutation (DYT1) is a childhood onset dystonia with rapid deterioration of symptoms, leading to severe disability in adolescence. Globus pallidus interna deep brain stimulation (GPi-DBS) has been shown to provide significant improvement in these cases.

METHODS

This was a retrospective study of TOR1A mutation positive dystonia patients, conducted at a university hospital from 2006 to 2018. Burke-Fahn-Marsden Dystonia Rating Scale (BFM-DRS) was used to evaluate dystonia severity before and after surgery. Emergence of postsurgical parkinsonian symptoms was evaluated using the Unified Parkinson Disease Rating Scale (UPDRS) part III. Montreal Cognitive Assessment (MOCA) was applied to assess cognitive dysfunction. SPSS version 18 was used for data analysis.

RESULTS

Eleven patients entered for analysis with an average age of 22.36 (±3.35) years (range: 18-28). Seven patients (63.6 %) were female. Mean follow-up period was 8.72 (±0.87). Difference between baseline and most recent BFM scores was significant (disability: 10.5 ±4.52 versus 2.09 (±3.20), P: 0.001; severity: 48.45 (±17.88) versus 9.36 (±10.47), P<0.001). The mean MOCA and UPDRS III scores after 7-9 years of DBS were 27.18 (±2.99), and 6.09 (±4.15), respectively.

CONCLUSION

Our experience confirms that GPi-DBS in pediatric patients with DYT1 dystonia is overall successful, with significant and long-lasting positive effects on motor and cognitive functions. There was no prominent side effect in long-term follow up.

Post-mortem histopathology of a pediatric brain after bilateral DBS of GPI for status dystonicus: case report and review of the literature

PURPOSE

To investigate the effects of deep brain stimulation (DBS) electrodes on the brain of a dystonic pediatric patient submitted to bilateral DBS of the globus pallidus internus (GPI).

METHODS

An 8-year-old male patient underwent bilateral DBS of GPI for status dystonicus. He died 2 months later due to multiorgan failure triggered by bacterial pneumonia. A post-mortem pathological study of the brain was done.

RESULTS

At visual inspection, no grossly apparent softening, hemorrhage, or necrosis of the brain adjacent to the DBS lead tracts was detected. High-power microscopic examination of the tissue surrounding the electrode trajectories showed lymphocyte infiltration, astrocytic gliosis, microglia, macrophages, and clusters of multinucleate giant cells. Significant astrocytosis was confirmed by GFAP staining in the electrode site. The T cell lymphocyte activity was overexpressed with activated macrophages detected with CD3, CD20, CD45, and CD68 stains respectively. There was no gliosis or leukocyte infiltration away from the surgical tracks of the electrodes.

CONCLUSION

This is the first post-mortem examination of a child's brain after bilateral DBS of GPI. The comparison with adult post-mortem reports showed no significant differences and confirms the safety of DBS implantation in the pediatric population too.

Deep Brain Stimulation of the Internal Pallidum in Lesch-Nyhan Syndrome: Clinical Outcomes and Connectivity Analysis

BACKGROUND

Lesch-Nyhan syndrome (LNS) is a rare genetic disorder characterized by a deficiency of hypoxanthine-guanine phosphoribosyltransferase enzyme. It manifests during infancy with compulsive self-mutilation behavior associated with disabling generalized dystonia and dyskinesia. Clinical management of these patients poses an enormous challenge for medical teams and carers.

OBJECTIVES

We report our experience with bilateral deep brain stimulation (DBS) of the globus pallidus internus (GPi) in the management of this complex disorder.

MATERIALS AND METHODS

Preoperative and postoperative functional assessment data prospectively collected by a multidisciplinary pediatric complex motor disorders team, including imaging, neuropsychology, and neurophysiology evaluations were analyzed with regards to motor and behavioral control, goal achievement, and patient and caregivers' expectations.

RESULTS

Four male patients (mean age 13 years) underwent DBS implantation between 2011 and 2018. Three patients received double bilateral DBS electrodes within the posteroventral GPi and the anteromedial GPi, whereas one patient had bilateral electrodes placed in the posteroventral GPi only. Median follow-up was 47.5 months (range 22-98 months). Functional improvement was observed in all patients and discussed in relation to previous reports. Analysis of structural connectivity revealed significant correlation between the involvement of specific cortical regions and clinical outcome.

CONCLUSION

Combined bilateral stimulation of the anteromedial and posteroventral GPi may be considered as an option for managing refractory dystonia and self-harm behavior in LNS patients. A multidisciplinary team-based approach is essential for patient selection and management, to support children and families, to achieve functional improvement and alleviate the overall disease burden for patients and caregivers.

DBS: a compelling example for ethical and legal reflection-a French perspective on ethical and legal concerns about DBS

Deep brain stimulation (DBS) is an approved treatment for neurological diseases and a promising one for psychiatric conditions, which may produce spectacular results very quickly. It is also a powerful tool for brain research and exploration. Beyond an overview of the ethical and legal literature on this topic, this paper aims at showing that DBS is a compelling example for ethical-legal reflection, as it combines a highly technical surgical procedure, a complex active medical device and neuromodulation of the human brain to restore lost abilities caused by a chronic and evolving disease. Some of the ethical and legal issues raised by DBS are not specific, but shed new light on medical ethics and law. Others are more DBS-specific, as they are linked to the intricacies of research and treatment, to the need to tune the device, to the patients' control over the device and its effects and to the involvement of family caregivers.

Medical and Surgical Treatments for Dystonia

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

Parental Attitudes Toward Deep Brain Stimulation in Adolescents with Treatment-Resistant Conditions

Objective: To examine parent's perceptions of deep brain stimulation (DBS) and whether DBS is perceived to be a viable and safe treatment for their adolescent child presenting with a severe, treatment-resistant neurological or psychiatric condition. Method: Two hundred and seventy-nine parents completed an online survey using Amazon Mechanical Turk (MTurk). Participants were presented with five vignette scenarios involving adolescents with severe, treatment-resistant neurological or psychiatric conditions: Rett syndrome, autism spectrum disorder, epilepsy, obsessive-compulsive disorder, and Tourette syndrome. Parents were then asked to evaluate each scenario and rate overall acceptability of using DBS to improve their child's core symptoms. Data were collected over a period of 2 weeks in the month of October 2018. Results: We found that parents reported favorable impressions of DBS regardless of the target condition, especially when greater improvement could be assured and when their child had the capacity to assist in the treatment decision-making. Parents indicated some reluctance to use DBS when possible safety concerns were present. Familiarity with DBS was directly associated with attitudes. Conclusions: The findings highlight an overall parental willingness to consider DBS as a treatment option for key symptoms of neurological and psychiatric conditions in adolescents.