Stimulation For Movement Disorders Research Articles

Use of cortical stimulation in neuropathic pain, tinnitus, depression, and movement disorders.

Medical treatment must strike a balance between benefit and risk. As the field of neuromodulation develops, decreased invasiveness, in combination with maintenance of efficacy, has become a goal. We provide a review of the history of cortical stimulation from its origins to the current state. The first part discusses neuropathic pain and the nonpharmacological treatment options used. The second part covers transitions to tinnitus, believed by many to be another deafferentation disorder, its classification, and treatment. The third part focuses on major depression. The fourth section concludes with the discussion of the use of cortical stimulation in movement disorders. Each part discusses the development of the field, describes the current care protocols, and suggests future avenues for research needed to advance neuromodulation.

The Development of Deep Brain Stimulation for Movement Disorders

The development of deep brain stimulation has revolutionized care for patients with movement disorders like Parkinson’s disease. Many areas of science contributed to this technology but one area, the use of animal models, has been cited as vital. We review these claims as well as the history of the discoveries that eventually led to deep brain stimulation in an attempt to ascertain: 1) the contributions of animal models; 2) the contributions from humanbased research and observation; and the role of advances in the engineering, physics, and computer science. We distinguish between advances and discoveries that were, or at least appear to be, dependent on animal models and those where animals were involved but that could have occurred, and/or were occurring simultaneously, with humanbased research. We conclude that animal-based research played a role in defining gross anatomy in the 19th and early 20th centuries, but that essentially all subsequent advances were human-based or secondary to advances in the physical and applied sciences. This has historical, funding, and ethical implications as the development of deep brain stimulation is cited as an example of the importance of animal-based research and a reason for continued social and financial support of animal models in general as opposed to clinical research, other human-based research modalities, and the various disciplines of the physical and applied sciences.

P41 Psychiatric side effects of bilateral deep brain stimulation for movement disorders

P41 Psychiatric side effects of bilateral deep brain stimulation for movement disorders

W2.1 Repetitive transcranial magnetic stimulation in movement disorders

W2.1 Repetitive transcranial magnetic stimulation in movement disorders

OVERVIEW OF COMMON MOVEMENT DISORDERS

Movement disorders are a diverse group of hypokinetic and hyperkinetic neurologic diseases characterized by abnormal function of the basal ganglia. In this chapter, we will discuss the four most common diagnoses encountered in subspecialty movement disorders clinics: Parkinson disease, essential tremor, dystonia, and spasticity. The presentation and natural history of each of these disorders varies widely in terms of age of onset, anatomic distribution, and severity. We will review the demographics, clinical characteristics, diagnostic criteria, natural history, and management of these diseases. The medical and surgical management of Parkinson disease will be covered in the chapters "Update on the Medical Management of Parkinson Disease" and "Deep Brain Stimulation in Movement Disorders," respectively.

PET Functional Imaging of Deep Brain Stimulation in Movement Disorders and Psychiatry

Deep brain stimulation (DBS) represents a major advance in the treatment of various severe movement disorders or neuropsychiatric diseases. Our understanding of the mechanism of action of this surgical treatment has greatly benefited from functional imaging studies. Most of these studies have been conducted in patients with Parkinson's disease (PD) treated by bilateral subthalamic nucleus (STN) stimulation. These studies have notably underlined the fact that STN stimulation influences motor, limbic, or associative cortical-subcortical loops in various (sometimes contradictory) ways. We present an up-to-date review of the information provided by functional imaging studies in surgery for PD, dystonia, tremor, as well as in psychiatric disorders such as depression or obsessive-compulsive disorder. On the basis of this information, proposed mechanisms of action of DBS are discussed, as well as the need for additional approaches such as improved anatomical localization of the contact used for stimulation or a better understanding of the electrical distribution around the electrode.

Mechanisms and Targets of Deep Brain Stimulation in Movement Disorders

Chronic electrical stimulation of the brain, known as deep brain stimulation (DBS), has become a preferred surgical treatment for medication-refractory movement disorders. Despite its remarkable clinical success, the therapeutic mechanisms of DBS are still not completely understood, limiting opportunities to improve treatment efficacy and simplify selection of stimulation parameters. This review addresses three questions essential to understanding the mechanisms of DBS. 1) How does DBS affect neuronal tissue in the vicinity of the active electrode or electrodes? 2) How do these changes translate into therapeutic benefit on motor symptoms? 3) How do these effects depend on the particular site of stimulation? Early hypotheses proposed that stimulation inhibited neuronal activity at the site of stimulation, mimicking the outcome of ablative surgeries. Recent studies have challenged that view, suggesting that although somatic activity near the DBS electrode may exhibit substantial inhibition or complex modulation patterns, the output from the stimulated nucleus follows the DBS pulse train by direct axonal excitation. The intrinsic activity is thus replaced by high-frequency activity that is time-locked to the stimulus and more regular in pattern. These changes in firing pattern are thought to prevent transmission of pathologic bursting and oscillatory activity, resulting in the reduction of disease symptoms through compensatory processing of sensorimotor information. Although promising, this theory does not entirely explain why DBS improves motor symptoms at different latencies. Understanding these processes on a physiological level will be critically important if we are to reach the full potential of this powerful tool.

Mechanisms of Deep Brain Stimulation in Movement Disorders as Revealed by Changes in Stimulus Frequency

Deep brain stimulation (DBS) is an established treatment for symptoms in movement disorders and is under investigation for symptom management in persons with psychiatric disorders and epilepsy. Nevertheless, there remains disagreement regarding the physiological mechanisms responsible for the actions of DBS, and this lack of understanding impedes both the design of DBS systems for treating novel diseases and the effective tuning of current DBS systems. Currently available data indicate that effective DBS overrides pathological bursts, low frequency oscillations, synchronization, and disrupted firing patterns present in movement disorders, and replaces them with more regularized firing. Although it is likely that the specific mechanism(s) by which DBS exerts its effects varies between diseases and target nuclei, the overriding of pathological activity appears to be ubiquitous. This review provides an overview of changes in motor symptoms with changes in DBS frequency and highlights parallels between the changes in motor symptoms and the changes in cellular activity that appear to underlie the motor symptoms.

Deep Brain Stimulation in Movement Disorders

Deep brain stimulation (DBS) is used for advanced and medically intractable patients with Parkinson's disease (PD), essential tremor (ET), and dystonia who meet strict criteria after a detailed motor, cognitive, and psychiatric evaluation. The potential targets are the ventral intermediate nucleus (VIM) of the thalamus for tremor, the globus pallidus interna (GPI) and the subthalamic nucleus (STN) for PD, and GPI for dystonia. The optimal target for PD has not been determined yet, although STN DBS has been performed more frequently in recent years. The mechanism of DBS effect is believed to be associated with disruption of pathological network activity in the cortico-basal ganglia-thalamic circuits by affecting the firing rates and bursting patterns of neurons and synchronized oscillatory activity of neuronal networks. Good candidates should be free of dementia, major psychiatric disorders, structural brain lesions, and important general medical problems. Although the risk for complications with DBS is less than with lesioning techniques, there is still a small risk for major complications associated with surgery. Bilateral procedures are more likely to cause problems with speech, cognition, and gait.

P27.1 Motor cortex stimulation for movement disorders and complex pain

P27.1 Motor cortex stimulation for movement disorders and complex pain

Neurophysiologic Intervention in Deep Brain Stimulation Treatment for Movement Disorders: A Practical Framework

Clinical neurophysiology has always played an important interventional role throughout the perioperative stages in functional neurosurgery. On the one hand, some neurophysiologic procedures have become an integrated part of neurosurgery. On the other hand, in deep brain stimulation, although the surgical electrode implantation is an essential step, the therapeutic effects are actually produced by electrically modulating the physiologic activity of the brain. We review the topic of neurophysiologic intervention in the deep brain stimulation for movement disorders by presenting the evidence derived from our own experiences based on an integrated group located at two hospitals in London and Oxford, UK, and mainly covering tremor caused by multiple sclerosis, Parkinson's disease and dystonia.

Deep brain stimulation in movement disorders: stereotactic coregistration of two-dimensional electrical field modeling and magnetic resonance imaging

Adjusting electrical parameters used in deep brain stimulation (DBS) for dystonia remains time consuming and is currently based on clinical observation alone. The goal of this study was to visualize electrical parameters around the electrode, to correlate these parameters with the anatomy of the globus pallidus internus (GPI), and to study the relationship between the volume of stimulated tissue and the electrical parameter settings. The authors developed a computer-assisted methodological model for visualizing electrical parameters (the isopotential and the isoelectric field magnitude), with reference to the stereotactic target, for different stimulation settings (monopolar and bipolar) applied during DBS. Electrical field values were correlated with the anatomy of the GPI, which was determined by performing stereotactic magnetic resonance imaging in one reference patient. By using this method it is possible to compare potential and electrical field distributions for different stimulation modes. In monopolar and bipolar stimulation, the shape and distribution of the potential and electrical field are different and depend on the stimulation voltage. Distributions visualized for patient-specific parameters can be subsequently correlated with anatomical information. The application of this method to one patient demonstrated that the 0.2-V/ mm isofield line fits best with the lateral GPI borders at the level of the stimulated contacts. The electrical field is a crucial parameter because it is assumed to be responsible for triggering action potentials. Electrical field visualization allows the calculation of the stimulated volume for a given isoline. Its application to an entire series of patients may help determine a threshold for obtaining a therapeutic effect, which is currently unknown, and consequently may aid in optimizing parameter settings in individual patients.

A novel quality of life instrument for deep brain stimulation in movement disorders

Objective: To develop a short instrument to examine quality of life (QoL) which specifically addresses patients with movement disorders treated by deep brain stimulation (DBS). Design: The instrument was developed...

Applications of transcranial magnetic stimulation in movement disorders.

The author reviews the applications of transcranial magnetic stimulation (TMS) in a series of movement disorders--namely, Parkinson's disease, corticobasal degeneration, multiple system atrophy, progressive supranuclear palsy, essential tremor, dystonia, Huntington's chorea, myoclonus, the ataxias, Tourette's syndrome, restless legs syndrome, Wilson's disease, Rett syndrome, and stiff-person syndrome. Single- and paired-pulse TMS studies have been done mainly for pathophysiologic purposes. Repetitive TMS has been used largely for therapy. Many TMS abnormalities are seen in the different diseases. They concur to show that motor cortical areas and their projections are the main target of the basal ganglia dysfunction typical of movement disorders. Interpretation has not always been clear, and sometimes there were discrepancies and contradictions. Largely, this may be the result of the extreme heterogeneity of the methods used and of the patients studied. It is premature to give repetitive TMS a role in treatment. Overall, however, TMS gives rise to a new, outstanding enthusiasm in the neurophysiology of movement disorders. There is reason to predict that TMS, with its continuous technical refinement, will prove even more helpful in the near future. Then, research achievements are reasonably expected to spill over into clinical practice.

Deep brain stimulation for movement disorders

Publisher Summary This chapter discusses deep brain stimulation (DBS) for movement disorder. DBS of the Vim nucleus of the thalamus had been successfully applied to patients with a thermo coagulation in the opposite thalamus and was then found to be safely applicable as a simultaneous bilateral procedure. The emerging concept of basal ganglia circuitry promoted exploration of the sub thalamic nucleus (STN) and the globus pallidus internus (GPi) as a DBS targets in Parkinson's disease. All parkinsonian symptoms can be improved with DBS of these two targets. Tremor of other than parkinsonian origin can still be best helped by thalamic stimulation. The GPi has attracted much interest recently as a DBS target for otherwise intractable dystonia. It is still not well understood how information is processed in the basal ganglia. The motor circuit of the basal ganglia originates in the frontal cortex, passes through striatum and globus pallidus, and enters the thalamus to be relayed back to the cortex.