Deep brain stimulation in the treatment of secondary dystonia:

Intraventricular baclofen for palliative management of acquired generalized dystonia in pediatric patients: a case series and literature review

Dystonia represents a significant source of disability in children. Generalized dystonia, which involves multiple body regions, leads to impaired mobility and motor function, resulting in substantial challenges in daily activities. Surgical treatments are used when medical treatments fail. Intrathecal baclofen (ITB) or deep brain stimulations (DBS) are the most employed surgical therapies. When these options are not feasible or ineffective, some authors have explored the use of intraventricular baclofen (IVB). In this report, we present four cases of pediatric patients with generalized dystonia who underwent treatment with IVB, resulting in notable improvements. To further explore the potential of this treatment modality, we conducted a comprehensive literature review. The findings from our study provide a comprehensive overview that can guide palliative management in similar cases.

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.

Electrophysiological insights into deep brain stimulation of the network disorder dystonia

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

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 in the Treatment of Tardive Dyskinesia

Tardive dyskinesia (TD) is a phenomenon observed following the predominantly long-term use of dopamine receptor blockers (antipsychotics) widely used in psychiatry. TD is a group of involuntary, irregular hyperkinetic movements, mainly in the muscles of the face, eyelid, lips, tongue, and cheeks, and less frequently in the limbs, neck, pelvis, and trunk. In some patients, TD takes on an extremely severe form, massively disrupting functioning and, moreover, causing stigmatization and suffering. Deep brain stimulation (DBS), a method used, among others, in Parkinson's disease, is also an effective treatment for TD and often becomes a method of last resort, especially in severe, drug-resistant forms. The group of TD patients who have undergone DBS is still very limited. The procedure is relatively new in TD, so the available reliable clinical studies are few and consist mainly of case reports. Unilateral and bilateral stimulation of two sites has proven efficacy in TD treatment. Most authors describe stimulation of the globus pallidus internus (GPi); less frequent descriptions involve the subthalamic nucleus (STN). In the present paper, we provide up-to-date information on the stimulation of both mentioned brain areas. We also compare the efficacy of the two methods by comparing the two available studies that included the largest groups of patients. Although GPi stimulation is more frequently described in literature, our analysis indicates comparable results (reduction of involuntary movements) with STN DBS.

Effectiveness of Thalamic Ventralis Oralis Anterior and Posterior Nuclei Deep Brain Stimulation for Posttraumatic Dystonia

Herein we report that the ventralis oralis anterior and posterior (Voa/Vop) nuclei of the thalamus may be effective alternative targets for deep brain stimulation (DBS) to improve posttraumatic dystonia when the globus pallidus interna is traumatically damaged. This patient presented at age 35 years with a clinical diagnosis of posttraumatic cervical and bilateral upper limb acquired dystonia resulting from intracerebral and intraventricular hemorrhage after a motorcycle accident at age 19 years. Due to a right globus pallidus interna traumatic lesion, conventional DBS targeting of the inferior basal ganglia was not possible; thus, the alternative Voa/Vop nuclei target was implanted. The patient realized significant benefit and at last follow-up 3 years postoperatively continued to endorse marked benefit and improvement of dystonia symptoms with minimal adverse effects from bilateral DBS implantation in the alternative targets of the Voa/Vop nuclei of the thalamus.

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.

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.

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.

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.

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

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

Deep brain stimulation in post-traumatic dystonia: A case series study

Aims

Deep brain stimulation (DBS) has been proposed as an effective treatment for drug‐intolerant isolated dystonia, but whether it is also efficacious for posttraumatic dystonia (PTD) is unknown. Reports are few in number and have reached controversial conclusions regarding the efficacy of DBS for PTD treatment. Here, we report a case series of five PTD patients with improved clinical benefit following DBS treatment.

Methods

Five patients with disabling PTD underwent DBS therapy. The clinical outcomes were assessed with the Burke–Fahn–Marsden dystonia rating scale (BFMDRS) at baseline and the last follow‐up visit (at more than 12 months).

Results

Patients 1 and 3 received unilateral globus pallidus internus (GPi) DBS for contralateral dystonia. The subthalamic nucleus (STN) was chosen as target for patients 2 and 4, due to a lesion located in the globus pallidus. Patient 5 had an electrode in the ventral intermediate nucleus (VIM) for treating predominant tremor of left upper extremity, with unexpected improvement of focal hand dystonia. The scores of BFMDRS movement exhibited favorable improvement in all five patients at the last follow‐up, ranging from 52.4% to 78.6%.

Conclusions

Deep brain stimulation may be an effective and safe treatment for medically refractory PTD, but this needs to be confirmed by further studies.

Comparison of Short-Term Stimulation of the Globus Pallidus Interna and Subthalamic Nucleus for Treatment of Primary Dystonia

OBJECTIVE

To compare the efficacy and side effects of bilateral globus pallidus internus (GPi) and subthalamic nucleus (STN) deep brain stimulation (DBS) in the same patient with primary dystonia.

METHODS

Patients with primary dystonia from the department of functional neurosurgery in Beijing Tiantan Hospital were recruited for the study. Four electrodes were bilaterally implanted in the GPi and STN. A trial stimulation was applied to determine the preliminary therapeutic effects. Five evaluations were conducted: preoperative, postoperative (before stimulation), after sham stimulation, and after stimulation for 24 hours of GPi and STN using optimal parameters, judged by the Burke-Fahn-Marsden Dystonia Rating Scale (BFMDRS).

RESULTS

The BFMDRS movement score decreased after both short-term GPi stimulation (from 15.3 ± 6.9 to 7.6 ± 4.2, P < 0.05) and short-term STN stimulation (from 15.3 ± 6.9 to 8.6 ± 5.0, P < 0.05). There were significant reductions in facial (eyes and mouth) movement scores after short-term GPi and STN DBS compared with baseline (P < 0.05), but not in cervical symptoms (P > 0.05). The cervical symptoms of tonic dystonia had an improvement after long-term DBS treatment (P < 0.05). There were more adverse events with STN DBS; however, most side effects could be ameliorated by adjusting stimulation parameters.

CONCLUSIONS

Both short-term GPi and STN stimulation improved the motor symptoms of dystonia, but there was no significant difference between GPi DBS and STN DBS. There were more side effects associated with STN stimulation.

Case Report: Targeting for Deep Brain Stimulation Surgery Using Chronic Recording and Stimulation in an Inpatient Neuromodulation Monitoring Unit, With Implantation of Electrodes in GPi and Vim in a 7-Year-Old Child With Progressive Generalized Dystonia

BACKGROUND

Deep brain stimulation for secondary dystonia has been limited by unknown optimal targets for individual children.

OBJECTIVES

We report the first case of a 7-year-old girl with severe generalized dystonia due to acquired striatal necrosis in whom we used a new method for identifying targets for deep brain stimulation.

METHODS

We implanted temporary depth electrodes in 5 different nuclei bilaterally in the basal ganglia and thalamus, with test stimulation and recording during 1 week while the child was an inpatient in a neuromodulation monitoring unit.

RESULTS

Single-unit activity in ventral intermedius Vim, internal globus pallidus (GPi), and subthalamic (STN) nuclei occurred during dystonic spasms and correlated with electromyography. Stimulation in Vim eliminated dystonic spasms. Subsequent implantation of 4 permanent deep brain stimulation electrodes in bilateral Vim and Gpi nuclei resolved dystonic spasms.

CONCLUSION

The use of temporary stimulation and recording electrodes to identify deep brain stimulation targets is a promising new technique that could improve outcomes in children with acquired dystonia.

Deep brain stimulation for stroke: Current uses and future directions

BACKGROUND

Survivors of stroke often experience significant disability and impaired quality of life related to ongoing maladaptive responses and persistent neurologic deficits. Novel therapeutic options are urgently needed to augment current approaches. One way to promote recovery and ameliorate symptoms may be to electrically stimulate the surviving brain. Various forms of brain stimulation have been investigated for use in stroke, including deep brain stimulation (DBS).

OBJECTIVE/METHODS

We conducted a comprehensive literature review in order to 1) review the use of DBS to treat post-stroke maladaptive responses including pain, dystonia, dyskinesias, and tremor and 2) assess the use and potential utility of DBS for enhancing plasticity and recovery from post-stroke neurologic deficits.

RESULTS/CONCLUSIONS

A large variety of brain structures have been targeted in post-stroke patients, including motor thalamus, sensory thalamus, basal ganglia nuclei, internal capsule, and periventricular/periaqueductal grey. Overall, the reviewed clinical literature suggests a role for DBS in the management of several post-stroke maladaptive responses. More limited evidence was identified regarding DBS for post-stroke motor deficits, although existing work tentatively suggests DBS-particularly DBS targeting the posterior limb of the internal capsule-may improve paresis in certain circumstances. Substantial future work is required both to establish optimal targets and parameters for treatment of maladapative responses and to further investigate the effectiveness of DBS for post-stroke paresis.

Drug-Induced Dyskinesia, Part 2: Treatment of Tardive Dyskinesia

Dyskinesias encompass a variety of different hyperkinetic phenomenologies, particularly chorea, dystonia, stereotypies, and akathisia. The main types of drug-induced dyskinesias include levodopa-induced dyskinesia (LID) in patients with Parkinson's disease and tardive syndrome (TS), typically present in patients with psychiatric or gastrointenstinal disorders treated with dopamine receptor blocking drugs, also referred to as neuroleptics. Besides preventive measures (i.e., avoiding the use of the offending drugs), general treatment strategies include slow taper of the offending agent and use of dopamine-depleting agents like tetrabenazine. Botulinum toxin may be helpful for wearing off focal dystonia and some forms of tardive dystonia. Deep brain stimulation is usually reserved for patients with disabling motor fluctuations, LID, and for severe TS that cannot be managed medically.

Deep brain stimulation for childhood dystonia: Is 'where' as important as in 'whom'?

Deep brain stimulation (DBS) has become a mainstay of dystonia management in adulthood. Typically targeting electrode placement in the GPi, sustained improvement in dystonic symptoms are anticipated in adults with isolated genetic dystonias. Dystonia in childhood is more commonly a symptomatic condition, with dystonia frequently expressed on the background of a structurally abnormal brain. Outcomes following DBS in this setting are much more variable, the reasons for which have yet to be elucidated. Much of the focus on improving outcomes following DBS in dystonia management has been on the importance of patient selection, with, until recently, little discussion of the choice of target. In this review, we advance the argument that patient selection for DBS in childhood cannot be made separate from the choice of target nuclei. The anatomy of common DBS targets is considered, and factors influencing their choice for electrode insertion are discussed. We propose an "ABC" for DBS in childhood dystonia is proposed: Appropriate Child selected; Best nuclei chosen for electrode insertion; Correct position within that nucleus.

Subthalamic nucleus deep brain stimulation in isolated dystonia: A 3-year follow-up study

OBJECTIVE

To report long-term safety and efficacy outcomes of a large cohort of patients with medically refractory isolated dystonia treated with subthalamic nucleus (STN) deep brain stimulation (DBS).

METHODS

Twenty patients (12 male, 8 female; mean age 49 ± 16.3 years) with medically refractory isolated dystonia were studied (14 were followed for 36 months). The primary endpoints were change in Burke-Fahn-Marsden Dystonia Rating Scale (BFMDRS) motor score and Toronto Western Spasmodic Torticollis Rating Scale (TWSTRS) total score at 36 months compared to preoperative baseline. Multiple secondary outcomes were also assessed (ClinicalTrials.gov NCT00773604).

RESULTS

Eighteen of 20 patients showed improvement 12 months after STN DBS with sustained benefit persisting for 3 years (n = 14). At 36 months, BFMDRS motor scores improved 70.4% from a mean 17.9 ± 8.5 to 5.3 ± 5.6 (p = 0.0002) and total TWSTRS scores improved 66.6% from a mean 41.0 ± 18.9 to 13.7 ± 17.9 (p = 0.0002). Improvement at 36 months was equivalent to that seen at 6 months. Disability and quality of life measures were also improved. Three hardware-related and 24 stimulation-related nonserious adverse events occurred between years 1 and 3 (including 4 patients with dyskinesia).

CONCLUSIONS

This study offers support for long-term tolerability and sustained effectiveness of STN DBS in the treatment of severe forms of isolated dystonia.

CLASSIFICATION OF EVIDENCE

This study provides Class IV evidence that STN DBS decreases long-term dystonia severity in patients with medically refractory isolated dystonia.

The Symptomatic Treatment of Acquired Dystonia: A Systematic Review

Background

Acquired dystonia is caused by an acquired or exogenous event. Although the therapeutic armamentarium used in clinical practice is more or less similar to that used for inherited or idiopathic dystonia, formal proof of the efficacy of these interventions in acquired dystonia is lacking.

Methods

The authors attempt to provide a comprehensive and systematic review of the current evidence for medical and allied health care treatment strategies in acquired dystonias. The PubMed, Cochrane Library, MEDLINE, Web of Science, PiCarta, and PsycINFO databases were searched up to December 2015, including randomized controlled trials, patient-control studies, and case series or single case reports containing a report on clinical outcome.

Results

There are level 3 practice recommendations for botulinum toxin injections and globus pallidus pars interna deep brain stimulation for tardive dystonia and dystonic cerebral palsy as well as intrathecal baclofen for dystonic cerebral palsy. There are insufficient and conflicting data on the effect (vs. the hazard) of other pharmacological interventions, and limited work has been done on other forms of neurostimulation and allied health care. Because no class A1 or A2 studies were identified, level 1 or 2 practice recommendations could not be deducted for a specific treatment intervention.

Conclusions

To improve the current medical and allied health care treatment options for patients with acquired dystonia, high-quality trials that examine the efficacy of therapies need to be performed.

Long-term outcome of globus pallidus internus deep brain stimulation in patients with Tourette syndrome

OBJECTIVE

To evaluate the effectiveness of deep brain stimulation (DBS) of the globus pallidus internus (GPi) on tic severity and common comorbidities in patients with severe Tourette syndrome that is refractory to pharmacological treatment and psychotherapy.

PATIENTS AND METHODS

We retrospectively assessed the long-term clinical outcomes of 13 patients with treatment-refractory Tourette syndrome who underwent DBS targeting the GPi at the Beijing Tiantan Hospital from January 1, 2006, through May 31, 2013. The primary outcome was a change in tic severity as measured by the Yale Global Tic Severity Scale, and the secondary outcome was a change in associated behavioral disorders and mood as measured by the Gilles de la Tourette Syndrome-Quality of Life Scale assessment.

RESULTS

Compared with baseline, the mean reduction in the total Yale Global Tic Severity Scale scores at last follow-up (mean, 41.9 months; range, 13-80 months) was 52.1% (range, 4.3%-83.6%), and the mean improvement rates at 1 month, 6 months, 12 months, 18 months, 24 months, 30 months, and 36 or more months were 11.8%, 20.0%, 26.8%, 36.7%, 44.7%, 49.0%, and 56.7%, respectively. A paired-sample t test revealed significant improvement of tic symptoms after 6 months of DBS programming (P<.05). The Gilles de la Tourette Syndrome-Quality of Life Scale score improved by a mean of 45.7% (range, 11.0%-77.2%).

CONCLUSION

This study is currently the largest reported GPi DBS case series of patients with treatment-refractory TS with the longest follow-up. Our results support the potential beneficial effect of GPi DBS on disabling tic reduction and improvement of quality of life.

Two-year outcomes of deep brain stimulation in adults with cerebral palsy

Objective

To investigate the effect of deep brain stimulation (DBS) on reducing dystonia and disability in adults with cerebral palsy (CP) and to compare the therapeutic outcomes between primary dystonia patients and CP patients over two years after bilateral pallidal DBS.

Methods

Five patients with primary dystonia and seven CP patients with dystonia were recruited. All subjects received DBS surgery in both globus pallidus. Burke-Fahn-Marsden dystonia rating scale consisting of dystonia movement score and disability score and subjective satisfaction scale were assessed after 1 month and every 6 months over two years following DBS treatment.

Results

On the dystonia movement scale, both groups of primary dystonia patients and CP patients showed a significant decrease over time following DBS. On the disability scale, patients with primary dystonia showed a significant decrease over time, whereas the disability score of CP patients did not change over the two years. Comparing the dystonia movement and disability scores of CP patients at each assessment, patients with primary dystonia showed a significant reduction after 6 months. Comparing the satisfaction scores of CP patients after DBS, patients with primary dystonia showed significantly higher subjective satisfaction.

Conclusion

Whereas dystonia can be significantly reduced in patients with primary dystonia, CP patients showed a modest improvement on the dystonia movement scale, but not on the disability scale. Therefore, DBS may be considered with caution as a treatment modality of CP patients with dystonia.

Surgical treatment for secondary dystonia

Surgical therapy for the secondary dystonias is generally perceived to be less effective than for primary disease. However, a number of case reports and small open series have recently appeared describing quite favorable outcomes following surgery for some nonprimary dystonias. We discuss surgical treatment options for this group of diverse conditions, including tardive dystonia, dystonic cerebral palsy, and certain heredodegenerative diseases in which deep brain stimulation and ablative lesions of the posteroventral pallidum have been shown to be effective. Other types of secondary dystonia respond less well to pallidal surgery, particularly when anatomical lesions of the basal ganglia are prominent on preoperative imaging. For these conditions, central baclofen delivery and botulinum toxin denervation may be considered. With optimal medical and surgical care, some patients with secondary dystonia have achieved reductions in disability and pain that approach those documented for primary dystonia.

Beyond the Burke-Fahn-Marsden Dystonia Rating Scale: deep brain stimulation in childhood secondary dystonia

PURPOSE

Deep brain stimulation is now widely accepted as an effective treatment for children with primary generalized dystonia. More variable results are reported in secondary dystonias and its efficacy in this heterogeneous group has not been fully elucidated. Deep brain stimulation outcomes are typically reported using impairment-focused measures, such as the Burke-Fahn-Marsden Dystonia Rating Scale, which provide little information about function and participation outcomes or changes in non-motor areas. The aim is to demonstrate that in some cases of secondary dystonia, the sole use of impairment level measures, such as the Burke-Fahn-Marsden Dystonia Rating Scale, may be insufficient to fully evaluate outcome following deep brain stimulation.

METHODS

Six paediatric cases who underwent deep brain stimulation surgery with a minimum of one year follow up were selected on the basis of apparent non-response to deep brain stimulation, defined as a clinically insignificant change in the Burke-Fahn-Marsden Dystonia Movement Scale (<20%), but where other evaluation measures demonstrated clinical efficacy across several domains.

RESULTS

Despite no significant change in Burke-Fahn-Marsden Dystonia Rating Scale scores following deep brain stimulation, parallel outcome measures demonstrated significant benefit in a range of child and family-centred goal areas including: pain and comfort, school attendance, seating tolerance, access to assistive technology and in some cases carer burden.

CONCLUSIONS

Sole use of impairment-focused measures, are limited in scope to evaluate outcome following deep brain stimulation, particularly in secondary dystonias. Systematic study of effects across multiple dimensions of disability is needed to determine what deep brain stimulation offers patients in terms of function, participation, care, comfort and quality of life. Deep brain stimulation may offer meaningful change across multiple domains of functioning, disability and health even in the absence of significant change in dystonia rating scales.

The effect of bilateral globus pallidus internus deep brain stimulation plus ventralis oralis thalamotomy on patients with cerebral palsy

OBJECTIVE

We compared bilateral globus pallidus internus (GPi) deep brain stimulation (DBS) with bilateral GPi DBS plus ventralis oralis (Vo) thalamotomy to analyze the effect of the combined Vo thalamotomy.

METHODS

Between March 2003 and December 2008, 10 patients underwent DBS and/or Vo thalamotomy for treatment of cerebral palsy in our institute of neurosurgery and rehabilitation medicine. Four patients received bilateral posteroventral GPi DBS as group I and 6 patients received GPi DBS plus unilateral thalamotomy as group II.

RESULTS

The movement and disability scores of group I improved by 32 and 14.3%, respectively, at the last follow-up compared with baseline. The movement and disability scores of group II improved by 31.5 and 0.18%. The BFMDRS-movement subscores of group II demonstrated statistically significant improvement in the contralateral arm compared to group I (p = 0.042). Body pain, vitality and mental health seemed to improve in group II, in terms of health-related quality of life.

CONCLUSIONS

Contrary to our expectations, we were unable to demonstrate clear improvements in overall BFMDRS scores between group I and group II. However, movements of the contralateral upper extremities improved and health-related quality of life in group II showed satisfactory results.

Early gene mapping after deep brain stimulation in a rat model of tardive dyskinesia: comparison with transient local inactivation

Deep brain stimulation (DBS) has been extensively used in Parkinson's disease and is also currently being investigated in tardive dyskinesia (TD), a movement disorder induced by chronic treatment with antipsychotic drugs such as haloperidol (HAL). In rodents, vacuous chewing movements (VCMs) following chronic HAL administration are suggested to model orofacial dyskinesias in TD. We show that 60 min of DBS (100 μA, 90 μs, 130 Hz) applied to the entopeduncular (EPN) or subthalamic (STN) nuclei significantly decreases HAL-induced VCMs. Using zif268 as a neural activity marker, we found that in HAL-treated animals EPN stimulation increased zif268 mRNA levels in the globus pallidus (+65%) and substantia nigra compacta (+62%) and reticulata (+76%), while decreasing levels in the motor cortex and throughout the thalamus. In contrast, after STN DBS zif268 levels in HAL-treated animals decreased in all basal ganglia structures, thalamus and motor cortex (range: 29% in the ventrolateral caudate-putamen to 100% in the EPN). Local tissue inactivation by muscimol injections into the STN or EPN also reduced VCMs, but to a lesser degree than DBS. When applied to the EPN muscimol decreased zif268 levels in substantia nigra (-29%), whereas STN infusions did not result in significant zif268 changes in any brain area. These results confirm the effectiveness of DBS in reducing VCMs and suggest that tissue inactivation does not fully account for DBS effects in this preparation. The divergent effects of STN vs. EPN manipulations on HAL-induced zif268 changes suggest that similar behavioral outcomes of DBS in these two areas may involve different neuroanatomical mechanisms.

Deep brain stimulation in children: experience and technical pearls

OBJECT

Deep brain stimulation (DBS) is an established technique for the treatment of several movement disorders in adults. However, the technical approach, complications, and results of DBS in children have not been well documented.

METHODS

A database of DBS implantations performed at a single institution, prospectively established in 1998, was reviewed for patients who received DBS prior to the age of 18. Diagnoses, surgical technique, and complications were noted. Outcomes were assessed using standard rating scales of neurological function.

RESULTS

Of 815 patients undergoing DBS implantation over a 12-year period, 31 were children (mean age at surgery 13.2 years old, range 4-17 years old). Diagnoses included the following: DYT1 primary dystonia (autosomal dominant, Tor1AΔGAG mutation, 10 cases), non-DYT1 primary dystonia (3 cases), secondary dystonia (11 cases), neurodegeneration with brain iron accumulation (NBIA, 3 cases), levodopa-responsive parkinsonism (2 cases), Lesch-Nyhan disease (1 case), and glutaric aciduria Type 1 (1 case). Six children ages 15-17 years old underwent awake microelectrode-guided surgery. For 25 children operated under general anesthesia, the surgical technique evolved from microelectrode-guided surgery to image-guided surgeries using real-time intraoperative MR imaging or CT for lead location confirmation. Complications included 5 hardware infections, all in children younger than 10 years old. At 1 year after implantation, patients with DYT1 dystonia had a mean improvement in the Burke-Fahn-Marsden Dystonia Rating Scale movement subscore of 75%, while those with secondary dystonia had only small improvements. Outcomes in the 3 children with NBIA were disappointing.

CONCLUSIONS

Results of DBS in children with primary and secondary dystonias were similar to those in adults, with excellent results for DYT1 dystonia in children without fixed orthopedic deformity and much more modest results in secondary dystonia. In contrast to reported experience in adults with NBIA, these results in children with NBIA were poor. Infection risk was highest in the youngest patients.

Treatment of secondary dystonia with a combined stereotactic procedure: long-term surgical outcomes

OBJECTIVE

There is some debate about the effects of pallidal deep brain stimulation (DBS) or lesioning on secondary dystonia. We applied a multimodal method to maximize the treatment effects of deep brain stimulation in patients with secondary dystonia.

METHODS

Between March 2003 and January 2009, four patients underwent bilateral globus pallidus internus (GPi) DBS and six patients underwent bilateral GPi DBS plus unilateral thalamotomy for treatment of cerebral palsy (CP). Among the patients with secondary dystonia without CP, five were also treated by DBS. We classified patients with generalized secondary dystonia with cerebral palsy into group I and patients with focal dystonia without CP into group II. Clinical outcome assessments were based on Burke-Fahn-Marsden Dystonia Rating Scale movement and disability scores. Heath-related quality of life was assessed with a 36-item short-form general health survey questionnaire preoperatively and at the last follow-up.

RESULTS

The movement and disability scores of group I-A had improved by 32.0% (P = 0.285) and 14.3% (P = 0.593), respectively, at the last follow-up compared with baseline. The movement and disability scores of group I-B had improved by 31.5% and 0.18% at the last follow-up compared with baseline, respectively. In comparison with patients in group I-A, patients in group I-B showed a significant improvement in movement scores for the contralateral arm (P = 0.042). Group II patients showed a marked improvement in movement and disability scores of 77.7% (P = 0.039) and 80.0% (P = 0.041), respectively.

CONCLUSIONS

We demonstrated that DBS plus unilateral ventralis oralis thalamotomy for CP patients with fixed states in the upper extremities is useful not only to treat secondary dystonic movement but also to improve quality of life. In group II patients with post-traumatic dystonia and tardive dyskinesia, we achieved excellent clinical outcomes using a stereotactic procedure.

Early postoperative management of DBS in dystonia: programming, response to stimulation, adverse events, medication changes, evaluations, and troubleshooting

Early postoperative management in deep brain stimulation-treated patients with dystonia differs from that of patients with essential tremor and Parkinson's disease, mainly due to the usually delayed effects of deep brain stimulation and the heterogenous clinical manifestation and etiologies of dystonia. The present chapter summarizes the available data about and concentrates on practical clinical aspects of early postoperative management in deep brain stimulation-treated patients with dystonia.

Intraoperative neurophysiology in DBS for dystonia

Deep brain stimulation (DBS) of the internal segment of the globus pallidus (GPi) has been demonstrated to be an effective therapy for the treatment of primary dystonia as well as tardive dystonia. Results for other forms of secondary dystonia have been less consistent. Although a number of target sites have been explored for the treatment of dystonia, most notably the motor thalamus, the target of choice remains the sensorimotor portion of the GPi. Although the optimal site within the GPi has not been determined, most centers agree that the optimal site involves the posteroventral lateral "sensorimotor" portion of the GPi. Microelectrode recording (MER) can be used to identify boundaries of the GPi and nearby white matter tracts, including the corticospinal tract and optic tract, and the sensorimotor GPi. However, whether or not the use of MER leads to improved outcomes compared with procedures performed without MER has not been determined. Currently, there is no evidence to support or refute the hypothesis that mapping structures with MER provides better short- or long-term outcomes. Centers using MER do not report a preference of one system over another, but there have not been any studies to compare the relative benefits or risks of using more than 1 electrode simultaneously. Comparison studies of different target structures and targeting techniques in dystonia have not been performed. Additional research, which includes comparative studies, is needed to advance our understanding and optimization of DBS targets, techniques, and approaches along with their relative benefits and risks in dystonia.

Long-Term management of DBS in dystonia: response to stimulation, adverse events, battery changes, and special considerations

Multiple independent case series have documented sustained benefit of bilateral pallidal deep brain stimulation (DBS) up to 3 years in patients with primary dystonia. Growing evidence exists for positive outcomes extending up to 10 years. The beneficial effects from DBS are usually reported to be stable, thus requiring little long-term modifications of the parameters of stimulation. Speech and swallowing abnormalities are less responsive than other dystonic symptoms. Symptom exacerbation after initial benefit has been reported in a few cases. It is not known whether this is related to potential tolerance or habituation to stimulation or to progression of the underlying disease. Failures of pallidal DBS, at least in primary dystonia patients, should not be accepted without further re-evaluation of each individual case, including possible revisions of the electrode location. Both hardware- and stimulation-related adverse effects, including insufficient relief of speech function, have been reported in the long-term. Despite early reports suggesting that hardware problems might be more frequent in dystonia, more recent studies did not confirm these observations. In patients with severe segmental (e.g., axial) or generalized dystonia, sudden cessation of stimulation may become a medical emergency and should be anticipated changing the neurostimulator before its natural end of life.

Dystonia due to cerebral palsy responds to deep brain stimulation of the globus pallidus internus

BACKGROUND

Cerebral palsy is the most common cause of pediatric-onset dystonia. Deep brain stimulation is gaining acceptance for treating dystonias in children. There is minimal reported experience regarding the efficacy of deep brain stimulation in cerebral palsy.

METHODS

Fourteen patients, including 8 younger than 16 years, received bilateral implants (13 patients) or a unilateral implant (1 patient) of the internal globus pallidus and were observed in a noncontrolled, nonblinded study for at least 6 months. Motor function was assessed using the Burke-Fahn-Marsden Dystonia Movement and Disability scales and the Barry Albright Dystonia Scale.

RESULTS

By 6 months, significant improvement was observed in the Burke-Fahn-Marsden Dystonia Movement scale (P=.004), the Burke-Fahn-Marsden Dystonia Disability scale (P=.027), and the Barry Albright Dystonia Scale (P=.029) for the whole cohort (n=14) and in the patients treated before skeletal maturity (group 1; n=8): Burke-Fahn-Marsden Dystonia Movement scale, P=.012; Burke-Fahn-Marsden Dystonia Disability scale, P=.020; and Barry Albright Dystonia Scale, P=.027.

CONCLUSIONS

Deep brain stimulation may offer an effective treatment option for cerebral palsy-related dystonia, especially in those treated before skeletal maturity.

Rescue leads: a salvage technique for selected patients with a suboptimal response to standard DBS therapy

OBJECT

We present four cases where supplementary "rescue" deep brain stimulation (DBS) leads were added for patients who failed to obtain anticipated clinical benefits.

METHODS

Nine patients out of 295 patients who underwent DBS between 2002 and 2009, were identified as rescue lead recipients. Of these nine cases, four cases were evaluated. Two had medication refractory tremor which was incompletely suppressed by Vim (nucleus ventralis intermedius) thalamic DBS, and supplemental rescue leads were implanted in either the VO (ventral oralis) thalamic nucleus or the STN (subthalamic nucleus). The remaining two cases were patients with severe dystonia who were initially treated with bilateral GPi (globus pallidus internus)-DBS, and following suboptimal clinical benefits, a second GPi rescue lead was added in a case, and bilateral STN rescue leads were added in the other case. Outcomes of scores collected included Fahn-Tolosa-Marin Tremor Rating Scale (TRS) for tremor cases and the Unified Dystonia Rating Scale (UDRS) for dystonia cases and the symptom specific patient global impression scales (PGIS; 7 point scale).

RESULTS

In the tremor cases, the TRS scale improved by 34.1 ± 7.4% and the PGIS following rescue lead was "minimally improved" to "very much improved" (range 1-2). In dystonia cases, the UDRS improved by 50.0 ± 23.6% and the PGIS was "minimally improved" to "very much improved" (range 1-2) after rescue lead surgery.

CONCLUSION

This small retrospective case series demonstrated that, in appropriately selected patients with suboptimal results of standard DBS therapy, the addition of rescue lead(s) may provide meaningful clinical benefit.

Chronic deep brain stimulation in patients with tardive dystonia without a history of major psychosis

Tardive dystonia usually occurs with a delay after neuroleptic exposure in patients with major psychosis. A subgroup of patients, however, is given such medication for "mild depression" or "neurasthenia." Tardive dystonia, in general, may respond favorably to pallidal deep brain stimulation (DBS). Nevertheless, it remains unclear thus far whether or not similar beneficial outcome is achieved with pallidal DBS in different subgroups of patients with tardive dystonia. Four women (mean age 59 years at surgery) underwent stereotactic pallidal DBS in the frame of an observational study. Tardive dystonia occurred secondary to medication with fluspirilene and haloperidol, and injection of long-acting depot neuroleptics prescribed for mild depression or "nervousness." Assessment included the Burke-Fahn-Marsden (BFM) scale preoperatively and at 12 months follow-up. Extended follow-up was available at a mean of 27.3 months postoperatively (range 16-36 months). There were no surgically related complications. All 4 patients experienced sustained statistically significant benefit from pallidal DBS. Mean improvement at 12 months was 77% for the BFM motor score (range, 45-91%; P = 0.043), and 84% at the last available follow-up (range, 70-91%; P = 0.03). This was paralleled by improvement of the BFM disability score. Chronic pallidal DBS in patients with tardive dystonia without a history of major psychosis provides sustained improvement which is similar to that in other subgroups of patients with tardive dystonia. This effect is stable on extended follow-up for up to 3 years.

Deep brain stimulation for dystonia: patient selection and outcomes

In a literature survey, 341 patients with primary and 109 with secondary dystonias treated with deep brain stimulation (DBS) of the internal segment of the globus pallidus (GPi) were identified. In general, the outcomes for primary dystonias were more favourable compared to the secondary forms. For some secondary dystonias--like tardive dystonia, myoclonus-dystonia (M-D), NBIA (PANK2), the outcome was very good. Only for the primary generalized dystonias, the efficacy of GPi-DBS has been confirmed in randomised controlled trials. Predictors of outcome are the experience and dedication of the stereotactic team, the selection of patients--the diagnosis and pre-operative screening--and the quality of the post-operative care. Predictors of negative outcome are long duration of the disease--with contractures or scoliosis--and concomitant symptoms like spasticity and cerebellar dysfunction. More studies are required to establish the role of GPi-DBS in the treatment of secondary dystonias.