Advances in DBS Technology and Novel Applications: Focus on Movement Disorders

PURPOSE OF REVIEW

Deep brain stimulation (DBS) is an established treatment in several movement disorders, including Parkinson's disease, dystonia, tremor, and Tourette syndrome. In this review, we will review and discuss the most recent findings including but not limited to clinical evidence.

RECENT FINDINGS

New DBS technologies include novel hardware design (electrodes, cables, implanted pulse generators) enabling new stimulation patterns and adaptive DBS which delivers potential stimulation tailored to moment-to-moment changes in the patient's condition. Better understanding of movement disorders pathophysiology and functional anatomy has been pivotal for studying the effects of DBS on the mesencephalic locomotor region, the nucleus basalis of Meynert, the substantia nigra, and the spinal cord. Eventually, neurosurgical practice has improved with more accurate target visualization or combined targeting. A rising research domain emphasizes bridging neuromodulation and neuroprotection. Recent advances in DBS therapy bring more possibilities to effectively treat people with movement disorders. Future research would focus on improving adaptive DBS, leading more clinical trials on novel targets, and exploring neuromodulation effects on neuroprotection.

Unilateral Campotomy of Forel for Acquired Hemidystonia: An Open-Label Clinical Trial

BACKGROUND

Hemidystonia (HD) is characterized by unilateral involuntary torsion movements and fixed postures of the limbs and face. It often develops after deleterious neuroplastic changes secondary to injuries to the brain. This condition usually responds poorly to medical treatment, and deep brain stimulation often yields unsatisfactory results. We propose this study based on encouraging results from case reports of patients with HD treated by ablative procedures in the subthalamic region.

OBJECTIVE

To compare the efficacy of stereotactic-guided radiofrequency lesioning of the subthalamic area vs available medical treatment in patients suffering from acquired HD.

METHODS

This is an open-label study in patients with secondary HD allocated according to their treatment choice, either surgical or medical treatment; both groups were followed for one year. Patients assigned in the surgical group underwent unilateral campotomy of Forel. The efficacy was assessed using the Unified Dystonia Rating Scale, Fahn-Marsden Dystonia Scale, Arm Dystonia Disability Scale, and SF-36 questionnaire scores.

RESULTS

Patients in the surgical group experienced significant improvement in the Unified Dystonia Rating Scale, Fahn-Marsden Dystonia Scale, and Arm Dystonia Disability Scale (39%, 35%, and 15%, respectively) 1 year after the surgery, with positive reflex in quality-of-life measures, such as bodily pain and role-emotional process. Patients kept on medical treatment did not experience significant changes during the follow-up. No infections were recorded, and no neurological adverse events were associated with either intervention.

CONCLUSION

The unilateral stereotaxy-guided ablation of Forel H1 and H2 fields significantly improved in patients with HD compared with optimized clinical treatment.

A translational perspective on pathophysiological changes of oscillatory activity in dystonia and parkinsonism

Intracerebral recordings from movement disorders patients undergoing deep brain stimulation have allowed the identification of pathophysiological patterns in oscillatory activity that correlate with symptom severity. Changes in oscillatory synchrony occur within and across brain areas, matching the classification of movement disorders as network disorders. However, the underlying mechanisms of oscillatory changes are difficult to assess in patients, as experimental interventions are technically limited and ethically problematic. This is why animal models play an important role in neurophysiological research of movement disorders. In this review, we highlight the contributions of translational research to the mechanistic understanding of pathological changes in oscillatory activity, with a focus on parkinsonism and dystonia, while addressing the limitations of current findings and proposing possible future directions.

Clinical features, pathophysiology, treatment, and controversies of tremor in dystonia

Dystonia and tremor frequently co-occur. In some cases, they have shared biological mechanisms, while in others dystonia and tremor are two comorbid conditions. The term "dystonic tremor" is used to describe tremor in those who have dystonia. Two mutually exclusive definitions of "dystonic tremor" were proposed. According to one definition, dystonic tremor is the tremor in the dystonic body part. An alternate definition of dystonic tremor entails irregular and jerky oscillations that have saw tooth appearance with or without overt dystonia. This paper outlines the differences in two definitions of dystonic tremor and identifies their limitations. Given the diverse views defining "dystonic tremor", this paper will use the term "tremor in dystonia". In addition, we will outline different ways to separate the subtypes of tremor in dystonia. Then we will discuss pathophysiological mechanisms derived from the objective measures and single neuron physiology analyses of tremor in dystonia. This article is part of the Special Issue "Tremor" edited by Daniel D. Truong, Mark Hallett, and Aasef Shaikh.

[Dystonia in cerebral palsy; what are the treatment options?]

Cerebral palsy (CP) is the most common cause of motor disability in children. The largest group of children with CP present with spasticity. Dystonia is estimated to be present in approximately 15% of children with CP, referred to as dyskinetic CP. Still, dystonia in CP remains underdiagnosed. Dystonia and spasticity can occur together in a subgroup of children with CP as well. Dystonia is characterized by fluctuating hypertonia and involuntary movement and postures. Dystonia in children with CP can interfere with motor function, caregiving and comfort. It is important to recognize dystonia in children with CP as specific treatment is indicated. In this paper we describe three cases of children with dystonia in CP and we review the pharmacological treatment options for dystonia in CP and the surgical options including intrathecal baclofen pump and deep brain stimulation.

Dual Pallidal and Thalamic Deep Brain Stimulation for Complex Ipsilateral Dystonia

PURPOSE

Globus pallidus pars interna (GPi) has become an established target for deep brain stimulation (DBS) in dystonia. Previous studies suggest that targeting the ventralis oralis (Vo) complex nucleus improves dystonic tremor or even focal dystonia. Research has also demonstrated that multi-target DBS shows some benefits over single target DBS. In this study, we reviewed patients who had undergone unilateral DBS targeting the GPi and Vo.

MATERIALS AND METHODS

Five patients diagnosed with medically refractory upper extremity dystonia (focal or segmental) underwent DBS. Two DBS electrodes each were inserted unilaterally targeting the ipsilateral GPi and Vo. Clinical outcomes were evaluated using the Burke-Fahn-Marsden Dystonia Rating Scale (BFMDRS) and Disability Rating Scale.

RESULTS

BFMDRS scores decreased by 55% at 1-month, 56% at 3-month, 59% at 6-month, and 64% at 12-month follow up. Disability Rating Scale scores decreased 41% at 1-month, 47% at 3-month, 50% at 6-month, and 60% at 12-month follow up. At 1 month after surgery, stimulating both targets improved clinical scores better than targeting GPi or Vo alone.

CONCLUSION

Unilateral thalamic and pallidal dual electrode DBS may be as effective or even superior to DBS of a single target for dystonia. Although the number of patients was small, our results reflected favorable clinical outcomes.

Movement Disorders in Children

CONTEXT

Movement disorders represent a common presentation in pediatrics and are often a source of clinical and diagnostic dilemmas. In this review, we provide an overview of common causes along with simplified clinical approach and management options for major movement disorders.

SOURCES

This narrative review is based on contemporary evidence and personal experience. Medline was searched for recent advances, current understanding and consensus on classification, clinical features, diagnosis and treatment.

RESULTS

Movement disorders are classified as hyperkinetic and hypokinetic disorders, the latter being rare in childhood. The hyperkinetic disorders include dystonia, chorea, athetosis, tics and tremor, stereotypies, myoclonus, startle syndromes and functional disorders. Some movement disorders can be benign and developmental. A large proportion of conditions are genetic in origin with a guarded prognosis. Some of the conditions may be post-infectious, immune-mediated or drug induced. Multiple types of movement disorders are present in many conditions. The age at onset, type and distribution of abnormal movements and presence of associated neurological and systemic features help in narrowing the differential diagnosis. The pharmacotherapy of movement disorders is complex and evolving.

CONCLUSION

A synopsis of movement disorders presenting in pediatric age has been provided, incorporating the latest evidence. A simplified approach for clinical diagnosis has been developed for dystonia and chorea.

Factors Influencing the Surgical Decision in Dystonia Patients Referred for Deep Brain Stimulation

There is no available data on the journey of dystonia patients once referred to a tertiary center to undergo deep brain stimulation (DBS). We hypothesized that some patients might be incorrectly diagnosed while others might decline the procedure or experience significant benefit with switching to a different botulinum neurotoxin (BoNT). This is a single-center, retrospective study of dystonia patients who were referred to the DBS program between January 2014 and December 2018. We collected data on the surgical decision as well as factors influencing this decision. Sixty-seven patients were included (30 males, mean age: 48.3 ± 20.1 years, disease duration: 16.9 ± 15.3 years). Thirty-three (49%) patients underwent DBS. Four (6%) patients were awaiting the procedure while the remaining 30 patients (45%) did not undergo DBS. Reasons for DBS decline were patient refusal (17, 53%), functional dystonia (6, 20%), and successful use of AbobotulinumtoxinA (3, 10%) in patients who had failed other BoNTs. Our study highlights the importance of structured patient education to increase acceptance of DBS, as well as careful patient evaluation, particularly with respect to functional dystonia. Finally, changing BoNT formulation might be beneficial in some patients.

Mechanisms of pallidal deep brain stimulation: Alteration of cortico-striatal synaptic communication in a dystonia animal model

Pallidal deep brain stimulation (DBS) is an important option for patients with severe dystonias, which are thought to arise from a disturbance in striatal control of the globus pallidus internus (GPi). The mechanisms of GPi-DBS are far from understood. Although a disturbance of striatal function is thought to play a key role in dystonia, the effects of DBS on cortico-striatal function are unknown. We hypothesised that DBS, via axonal backfiring, or indirectly via thalamic and cortical coupling, alters striatal function. We tested this hypothesis in the dtsz hamster, an animal model of inherited generalised, paroxysmal dystonia. Hamsters (dystonic and non-dystonic controls) were bilaterally implanted with stimulation electrodes in the GPi. DBS (130 Hz), and sham DBS, were performed in unanaesthetised animals for 3 h. Synaptic cortico-striatal field potentials, as well as miniature excitatory postsynaptic currents (mEPSC) and firing properties of medium spiny striatal neurones were recorded in brain slice preparations obtained immediately after EPN-DBS. The main findings were as follows: a. DBS increased cortico-striatal evoked responses in healthy, but not in dystonic tissue. b. Commensurate with this, DBS increased inhibitory control of these evoked responses in dystonic, and decreased inhibitory control in healthy tissue. c. Further, DBS reduced mEPSC frequency strongly in dystonic, and less prominently in healthy tissue, showing that also a modulation of presynaptic mechanisms is likely involved. d. Cellular properties of medium-spiny neurones remained unchanged. We conclude that DBS leads to dampening of cortico-striatal communication, and restores intrastriatal inhibitory tone.

Fifteen-minute consultation: Approach to investigation and management of childhood dystonia

Dystonia is a hyperkinetic movement disorder characterised by sustained or intermittent muscle contractions causing abnormal movements, postures or both. Dystonia is a challenging condition to diagnose and treat. Dystonia is often under-recognised in children, particularly in cerebral palsy, and frequently coexists with spasticity. This guide aims to simplify the approach to diagnosis, investigation and treatment of childhood-onset dystonia. The principle of treatment is similar regardless of the underlying aetiology: identification of potential triggers and consideration of both pharmacological and surgical options.

Treatment of diaphragmatic dystonia with pallidal deep brain stimulation

We present the case of a 70-year-old woman with treatment-refractory diaphragmatic dystonia. Patient initially presented with blepharospasms followed by development of involuntary inspiratory spasms during speech. Her symptoms were drug-refractory, and she therefore underwent awake bilateral pallidal deep brain stimulation with microelectrode recording. No intraoperative or postoperative complications or adverse events occurred, and there were no undesired effects of stimulation. Using contacts in bilateral dorsal globus pallidus interna and ventral globus pallidus externa, symptoms alleviated after a latency period of 2-4 weeks. At 5-month follow-up, the patient maintained a 16.5-point reduction in Burke-Fahn-Marsden movement scale (from 20/120 to 3.5/120) with resolution of blepharospasm, irregular inspirations and broken and irregular speech.

Treatment of Dystonia: Medications, Neurotoxins, Neuromodulation, and Rehabilitation

Dystonia is a complex disorder with numerous presentations occurring in isolation or in combination with other neurologic symptoms. Its treatment has been significantly improved with the advent of botulinum toxin and deep brain stimulation in recent years, though additional investigation is needed to further refine these interventions. Medications are of critical importance in forms of dopa-responsive dystonia but can be beneficial in other forms of dystonia as well. Many different rehabilitative paradigms have been studied with variable benefit. There is growing interest in noninvasive stimulation as a potential treatment, but with limited long-term benefit shown to date, and additional research is needed. This article reviews existing evidence for treatments from each of these categories. To date, there are many examples of incomplete response to available treatments, and improved therapies are needed.

Pediatric Deep Brain Stimulation for Dystonia: Current State and Ethical Considerations

Dystonia is a movement disorder that can have a debilitating impact on motor functions and quality of life. There are 250,000 cases in the United States, most with childhood onset. Due to the limited effectiveness and side effects of available treatments, pediatric deep brain stimulation (pDBS) has emerged as an intervention for refractory dystonia. However, there is limited clinical and neuroethics research in this area of clinical practice. This paper examines whether it is ethically justified to offer pDBS to children with refractory dystonia. Given the favorable risk-benefit profile, it is concluded that offering pDBS is ethically justified for certain etiologies of dystonia, but it is less clear for others. In addition, various ethical and policy concerns are discussed, which need to be addressed to optimize the practice of offering pDBS for dystonia. Strategies are proposed to help address these concerns as pDBS continues to expand.

Auditory-Perceptual Evaluation of Deep Brain Stimulation on Voice and Speech in Patients With Dystonia

OBJECTIVE

To determine the effects of globus pallidus interna (GPi) deep brain stimulation (DBS) on speech and voice quality of patients with primary, medically refractory dystonia.

METHODS

Voices of 14 patients aged ≥18 years (males = 7 and females = 7) with primary dystonia (DYT1 gene mutation dystonia = 4, cervical dystonia = 6, and generalized dystonia = 4) with bilateral GPi DBS were assessed. Five blinded raters (two fellowship-trained laryngologists and three speech/language pathologists) evaluated audio recordings of each patient pre- and post-DBS. Perceptual voice quality was rated using the Grade, Roughness, Breathiness, Asthenia, and Strain scale and changes in speech intelligibility were assessed with the Clinical Global Impression scale of Severity instrument. Inter-rater and intrarater reliability rates for perceptual voice ratings were assessed using the kappa coefficient.

RESULTS

Voice quality parameters showed mean improvements in Grade (P < 0.0001), Roughness (P = 0.0043), and Strain (P < 0.0001) 12 months post-DBS. Asthenia increased from baseline to 6 months (P = 0.0022) and declined significantly from 6 to 12 months (P = 0.0170). Breathiness did not change significantly over time. Speech intelligibility also improved from 6 to 12 months (P = 0.0202) and from pre-DBS to 12 months post-DBS (P = 0.0022). Grade and Strain ratings had nearly perfect and substantial inter-rater agreement (0.84 and 0.71, respectively).

CONCLUSIONS

Voice and speech intelligibility improved after bilateral GPi DBS for dystonia. GPi DBS may emerge as a potential treatment option for patients with medically refractory laryngeal dystonia.

Predictive factors for outcome of pallidal deep brain stimulation in cervical dystonia

OBJECTIVE

Primary cervical dystonia (CD) is characterized by abnormal contractions of neck muscles. Globus pallidus internus deep brain stimulation (GPi-DBS) is recognized as an effective therapy for patients with refractory CD, but the prognostic factors need further research. Our study investigated the predictive factors of clinical outcomes in CD patients who underwent GPi-DBS.

PATIENTS AND METHODS

Patients (n = 23) who underwent GPi-DBS at Chinese PLA General Hospital from March 2012 to April 2018 were included in our analysis. Their scores of Toronto Western Spasmodic Torticollis Rating Scale (TWSTRS) and Tsui were acquired at baseline and at the last follow-up visit. Percent improvement in these scores were compared between the categorical variables. Correlations between outcomes and continuous demographic and clinical variables were calculated.

RESULTS

Patients showed significant improvement in TWSTRS total (55.71 %), severity (48.75 %), disability (57.05 %), pain (63.67 %) scores and total Tsui score (46.07 %, all P ﹤0.001). Follow-up duration was positively correlated with percent improvement in TWSTRS total (rho = 0.594, P =  0.003), severity (rho = 0.581, P =  0.004) and disability (rho = 0.470, P =  0.023) scores. No significant differences in the outcomes were found between any pair of the categorical variables.

CONCLUSIONS

Follow-up duration was the only independent factor correlated to the outcomes of GPi-DBS for CD patients. However, follow-up duration is an indefinite factor prior to surgery, thus further studies are needed before the final conclusions of prognostic factors are established.

The Dystonias

PURPOSE OF REVIEW

This article provides a summary of the state of the art in the diagnosis, classification, etiologies, and treatment of dystonia.

RECENT FINDINGS

Although many different clinical manifestations of dystonia have been recognized for decades, it is only in the past 5 years that a broadly accepted approach has emerged for classifying them into specific subgroups. The new classification system aids clinical recognition and diagnosis by focusing on key clinical features that help distinguish the many subtypes. In the past few years, major advances have been made in the discovery of new genes as well as advances in our understanding of the biological processes involved. These advances have led to major changes in strategies for diagnosis of the inherited dystonias. An emerging trend is to move away from heavy reliance on the phenotype to target diagnostic testing toward a broader approach that involves large gene panels or whole exome sequencing.

SUMMARY

The dystonias are a large family of phenotypically and etiologically diverse disorders. The diagnosis of these disorders depends on clinical recognition of characteristic clinical features. Symptomatic treatments are useful for all forms of dystonia and include oral medications, botulinum toxins, and surgical procedures. Determination of etiology is becoming increasingly important because the number of disorders is growing and more specific and sometimes disease-modifying therapies now exist.

Tremor

PURPOSE OF REVIEW

Tremor may be defined as an involuntary movement that is rhythmic (ie, regularly recurrent) and oscillatory (ie, rotating around a central plane) and may manifest in a variety of ways; accordingly, tremor has a rich clinical phenomenology. Consequently, the diagnosis of tremor disorders can be challenging, and misdiagnoses are common. The goal of this article is to provide the reader with straightforward approaches to the diagnosis and treatment of tremors.

RECENT FINDINGS

Focused ultrasound thalamotomy of the ventral intermediate nucleus of the thalamus is an emerging and promising therapy for the treatment of essential tremor.

SUMMARY

The evaluation should start with a detailed tremor history followed by a focused neurologic examination, which should attend to the many subtleties of tremor phenomenology. Among other things, the history and examination are used to establish whether the primary tremor is an action tremor (ie, postural, kinetic, or intention tremor) or a resting tremor. The clinician should then formulate two sets of diagnoses: disorders in which action tremor is the predominant tremor versus those in which resting tremor is the predominant tremor. Among the most common of the former type are essential tremor, enhanced physiologic tremor, drug-induced tremor, dystonic tremor, primary writing tremor, orthostatic tremor, and cerebellar tremor. Parkinson disease is the most common disorder of resting tremor. This article details the clinical features of each of these disorders, as well as those of additional tremor disorders.

[Deep brain stimulation for movement disorders]

Deep brain stimulation (DBS) is a treatment which uses high-frequency electric stimulation to suppress pathological brain activity. DBS has been applied for over 30 years now, particularly in patients with severe movement disorders, such as Parkinson's disease, dystonia and tremor. Although there is clearly scientific evidence for the effectiveness of DBS in these three movement disorders, the effect size of the treatment remains limited. Furthermore, DBS is not curative and can only be applied in a select subset of patients. In this article, we discuss the key indications and contraindications for DBS, and the outcomes achieved when it is applied in the aforementioned movement disorders. We discuss the most notable controversies and new developments in the field of deep brain stimulation, in order to offer referrers and fellow healthcare professionals an accessible introduction to this mode of therapy.

Recognizing Movement Disorder Emergencies - A Practical Review For Non-Neurologist

Neurology still remains one of the most underserved specialties of medicine in Pakistan with roughly one neurologist per million people. Movement disorders (MD) are neurological problems that interfere with patient's motor abilities and diagnosis is typically clinical. In this review, we describe a practical approach to common MD emergencies that may be encountered by a non-neurologist physician, emphasizing on formulating a working diagnosis and their immediate management. Movement disorder emergencies can be classified based on MD phenomenology and we will provide a brief overview of dystonia including acute dystonic reaction, PAID syndrome and dystonic storm; chorea, myoclonus including serotonin syndrome and startle disease; and rigidity including neuroleptic malignant syndrome and malignant hyperthermia.

Protocol for N-of-1 trials with replications across therapists for childhood-onset dystonia rehabilitation: Study 2: Protocole des essais à effectif unique avec répétitions par différents ergothérapeutes pour la réadaptation de la dystonie débutant dans l'enfance : Étude 2

BACKGROUND

Currently, no evidence-based rehabilitation interventions are available for hyperkinetic movement disorders (HMD), including dyskinetic cerebral palsy (CP). Among these highly heterogeneous disorders, dystonia is the predominant disorder. The Cognitive Orientation to daily Occupational Performance (CO-OP) Approach-a task-oriented, performance-based intervention to enable participation-is currently being evaluated for its potential as an intervention option.

PURPOSE

This paper reports the protocol for the second of two studies designed to evaluate the potential of CO-OP to improve functional outcomes for individuals with HMD following deep brain stimulation (DBS). This second study is a systematic replication across multiple treating therapists from multiple centres.

METHOD

Systematic replications will be used across centres and treating therapists trained in the CO-OP, using a series of randomized multiple-baseline N-of-1 trials. Participants will be ages 6 to 21 years with HMD and DBS as indicated by the Manual Ability Classification System. Data collection will involve multiple data points collected at baseline, during intervention, and after intervention. The intervention will involve occupation-based goal setting followed by 10 individualized CO-OP sessions. The primary outcome measures are the Performance Quality Rating Scale and the Canadian Occupational Performance Measure. Outcome data will be plotted over time for each participant and supplemented with graph statistical analysis and estimate size effect for N-of-1 trials.

IMPLICATIONS

The results of this study will help to inform future training procedures and future clinical trials.

Protocol for N-of-1 trials proof of concept for rehabilitation of childhood-onset dystonia: Study 1: Protocole des essais de validation à effectif unique pour la réadaptation de la dystonie débutant dans l'enfance : Étude 1

BACKGROUND

Hyperkinetic movement disorders (HMD) are a heterogeneous group of neurological conditions among which dystonia is the predominant disorder and dyskinetic cerebral palsy the largest secondary dystonia group. Currently, there are no evidence-based, non-medical management options for childhood HMD. The Cognitive Orientation to daily Occupational Performance (CO-OP) Approach is a task-oriented, performance-based intervention that focuses on participation.

PURPOSE

This paper reports the protocol for a proof-of-concept study to assess feasibility and preliminary evidence regarding efficacy of CO-OP for HMD following deep brain stimulation (DBS).

METHOD

A series of N-of-1 trials with replications will be conducted with children, ages 6 and 21 years with HMD and DBS as indicated by the Manual Ability Classification System. Ten individualized CO-OP sessions, with multiple baselines before, during, and after, will be completed. The primary outcome measures are the Performance Quality Rating Scale and the Assessment of Motor and Process Skills. Outcome data will be plotted over time for each participant and supplemented with graph statistical analysis and effect size estimates.

IMPLICATIONS

A written protocol will be developed based on evidence and feedback incorporating any changes to the CO-OP intervention for children and young people with HMD, as per the Medical Research Council's Framework for Complex Interventions.

Radiofrequency Lesioning Through Deep Brain Stimulation Electrodes in Patients with Generalized Dystonia

BACKGROUND

Deep brain stimulation (DBS) is an established treatment for generalized dystonia. However, the DBS device is sometimes removed owing to hardware complications. We present 4 cases of generalized dystonia treated with radiofrequency lesioning through DBS electrodes.

CASE DESCRIPTION

Four patients, 3 men and 1 woman (age range, 34-44 years), underwent DBS for generalized dystonia and subsequently developed complications, such as infection, necessitating removal of the devices. As stopping the stimulation caused recurrence of uncontrollable symptoms, radiofrequency lesioning was performed through the DBS electrodes under local anesthesia, and the DBS systems were removed under local or generalized anesthesia thereafter. The procedures performed were as follows: 2 patients had bilateral pallidotomy, 1 patient had unilateral pallidotomy, and 1 patient had pallidotomy and ipsilateral thalamotomy. As a result, in 4 patients, the dystonic symptoms did not worsen even after removal of the DBS systems during a follow-up period of 1-12 years. However, 1 patient had a small hemorrhage, and 2 patients showed recurrence of dystonia.

CONCLUSIONS

Radiofrequency lesioning with DBS electrodes is feasible in cases of generalized dystonia when the DBS leads have to be removed.

Diagnosis and treatment of pediatric onset isolated dystonia

Isolated dystonia refers to a genetic heterogeneous group of progressive conditions with onset of symptoms during childhood or adolescence, progressive course with frequent generalization and marked functional impairment. There are well-known monogenic forms of isolated dystonia with pediatric onset such as DYT1 and DYT6 transmitted with autosomal dominant inheritance and low penetrance. Genetic findings of the past years have widened the etiological spectrum and the phenotype. The recently discovered genes (GNAL, ANO-3, KTM2B) or variant of already known diseases, such as Ataxia-Teleangectasia, are emerging as another causes of pediatric onset dystonia, sometimes with a more complex phenotype, but their incidence is unknown and still a considerable number of cases remains genetically undetermined. Due to the severe disability of pediatric onset dystonia treatment remains unsatisfactory and still mainly based upon oral pharmacological agents. However, deep brain stimulation is now extensively applied with good to excellent results especially when patients are treated early during the course of the disease.

Hyperbaric oxygen for late sequelae of carbon monoxide poisoning enhances neurological recovery: case report

Neuropsychiatric sequelae have been reported in 15%-45% of survivors of carbon monoxide (CO) poisoning. Hyperbaric oxygen (HBO₂) therapy reduces the incidence of cognitive and neurological a dysfunction. The efficacy of providing HBO₂ beyond the first one to two days after initial insult is unknown. However, some evidence exists for the benefit of this treatment. We report on treating a patient 14 months after CO injury, who responded with markedly improved neurologic status. A 27-year-old scholar was found comatose due to CO poisoning (carboxyhemoglobin = 31.7%). He received five acute HBO₂ treatments. After discharge, he developed chorea, Parkinsonism, dystonia, memory loss, slowed processing speed and verbal fluency, leaving him disabled. After the patient reached a clinical plateau, HBO₂ was tried again at 90 minutes at 2.4 ATA plus air breaks. Neuropsychological testing was performed at baseline and after each 20 HBO₂ cycles, five of which were performed during the period from 14-22 months after CO exposure. After the first 20 treatments, Parkinsonism and dystonia improved. After 40 sessions, further improvements were seen on mental speed, verbal fluency, and fine motor movements. The outcome following 100 treatments was that the patient regained independence, including the ability to drive and to become gainfully employed. Our case calls into question the concept that HBO₂ therapy has no role during the chronic phase of CO brain injury. Randomized clinical trials should be considered to evaluate the therapeutic efficacy of HBO₂ in patients with neurological sequelae following CO injury.

Muscle Selection for Focal Limb Dystonia

Selection of muscles for botulinum toxin injection for limb dystonia is particularly challenging. Limb dystonias vary more widely in the pattern of dystonic movement and involved muscles than cervical dystonia or blepharospasm. The large variation in how healthy individuals perform skilled hand movements, the large number of muscles in the hand and forearm, and the presence of compensatory actions in patients with dystonia add to the complexity of choosing muscles for injection. In this article, we discuss approaches to selecting upper and lower extremity muscles for chemodenervation treatment of limb dystonia.