Early application of deep brain stimulation: Clinical and ethical aspects

Arching deep brain stimulation in dystonia types

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

Attitudes toward use and timing of deep brain stimulation: a patient's with DBS perspective

OBJECTIVE

To guide responsive policy and better understand factors that might shape patients' decisions to have DBS earlier, we explore perspectives and attitudes toward earlier deep brain stimulation (DBS) of Parkinson disease (PD) patients with DBS.

INTRODUCTION

Before the US Food and Drug Administration released its change of indication for the use of DBS for PD, several groups had performed DBS earlier in disease course.

METHODS

We designed an online survey comprising Likert-type, multiple choice, and rank-order questions and distributed it to PD patients. We analyzed patient considerations for having chosen DBS and for choosing or rejecting to have DBS earlier, as well as factors potentially shaping perspectives around DBS and its timing. Data was analyzed using descriptive and inferential statistics.

RESULTS

Among the 160 participants in the sample, the most important consideration for choosing DBS was the possibility of better symptomatic control compared to medication alone. The most important consideration for delaying DBS was possible ineffectiveness. 41.3 % (n = 66) of respondents supported earlier DBS use, 38.8 % (n = 62) did not, and the remainder (n = 30) were uncertain. Patients who supported earlier DBS use cited the possibility of better symptomatic control than with medication alone, while those who did not support earlier use felt that medication options should be exhausted first.

CONCLUSION

Our results suggest that there are multiple factors shaping patient perceptions around earlier DBS implantation. Future work should compare perceptions before and after DBS implantation, as well as pair perceptions with clinical outcomes.

Challenges to Ethically Managing Parkinson Disease: An Interview Study of Patient Perspectives

This study investigated the current ethical issues in relation to recognizing and managing Parkinson disease (PD) from the patient's perspective.

METHODS

Twelve patients living with PD who were from the medical school's Patients as Educators program were recruited. Semistructured interviews were conducted to record patient experiences in order to identify potential ethical issues in relation to recognizing and managing PD. Thematic analysis was applied to the interview transcripts.

RESULTS

Four key themes emerged from the interviews. These were information giving, coping, identity, and future medical treatment. These data indicate variable experiences in relation to communication between patient and health-care professional, better support for both planning end-of-life decisions and in coping with the disease's impacts on their identity. Patients with PD also struggle with access to support services and support for main carer.

IMPLICATIONS

To ensure ethical practice in supporting patients with PD, these emerging themes need further investigation; and management guidelines relevant to PD must be informed by research in this area to ensure ethical care of patients with PD, their carers, and families.

Early versus Late Application of Subthalamic deep brain Stimulation to Parkinson's disease patients with motor complications (ELASS): protocol of a multicentre, prospective and observational study

INTRODUCTION

Deep brain stimulation (DBS) of the subthalamic nucleus (STN) is a well-established surgical treatment for Parkinson's disease (PD). However, there is currently no consensus on the best timing for this surgery. The aim of our study is to compare the therapeutic efficacy of bilateral STN DBS in patients with PD with early and late motor complications.

METHODS AND ANALYSIS

200 patients with PD will be enrolled in this multicentre, prospective, observational study, and will be followed up for 4 years. Patients with PD who meet the criteria for STN DBS surgery will be allocated to either the early stimulation group or the late stimulation group based on the duration of their motor complications. The primary outcome will be changes in quality of life from baseline to 4 years, measured using the 39-item Parkinson's Disease Questionnaire Summary Index. The secondary outcomes include changes in motor function measured using Movement Disorder Society-revised Unified Parkinson's Disease Rating Scale (MDS-UPDRS) Part III, self-reported experiences of daily living measured using MDS-UPDRS Part I B and Part II, good 'on' time recorded by the patients using a diary and safety profile of both groups.

ETHICS AND DISSEMINATION

The study received ethical approval from the Medical Ethical Committee of the First Affiliated Hospital, Sun Yat-sen University. The results of this study will be published in peer-reviewed journals and presented at international conferences.

TRIAL REGISTRATION NUMBER

NCT01922388; Pre-results.

Subthalamic nucleus deep brain stimulation on motor-symptoms of Parkinson's disease: Focus on neurochemistry

Deep brain stimulation (DBS) has become a standard therapy for Parkinson's disease (PD) and it is also currently under investigation for other neurological and psychiatric disorders. Although many scientific, clinical and ethical issues are still unresolved, DBS delivered into the subthalamic nucleus (STN) has improved the quality of life of several thousands of patients. The mechanisms underlying STN-DBS have been debated extensively in several reviews; less investigated are the biochemical consequences, which are still under scrutiny. Crucial and only partially understood, for instance, are the complex interplays occurring between STN-DBS and levodopa (LD)-centred therapy in the post-surgery follow-up. The main goal of this review is to address the question of whether an improved motor control, based on STN-DBS therapy, is also achieved through the additional modulation of other neurotransmitters, such as noradrenaline (NA) and serotonin (5-HT). A critical issue is to understand not only acute DBS-mediated effects, but also chronic changes, such as those involving cyclic nucleotides, capable of modulating circuit plasticity. The present article will discuss the neurochemical changes promoted by STN-DBS and will document the main results obtained in microdialysis studies. Furthermore, we will also examine the preliminary achievements of voltammetry applied to humans, and discuss new hypothetical investigational routes, taking into account novel players such as glia, or subcortical regions such as the pedunculopontine (PPN) area. Our further understanding of specific changes in brain chemistry promoted by STN-DBS would further disseminate its utilisation, at any stage of disease, avoiding an irreversible lesioning approach.

Toward sophisticated basal ganglia neuromodulation: Review on basal ganglia deep brain stimulation

This review presents state-of-the-art knowledge about the roles of the basal ganglia (BG) in action-selection, cognition, and motivation, and how this knowledge has been used to improve deep brain stimulation (DBS) treatment of neurological and psychiatric disorders. Such pathological conditions include Parkinson's disease, Huntington's disease, Tourette syndrome, depression, and obsessive-compulsive disorder. The first section presents evidence supporting current hypotheses of how the cortico-BG circuitry works to select motor and emotional actions, and how defects in this circuitry can cause symptoms of the BG diseases. Emphasis is given to the role of striatal dopamine on motor performance, motivated behaviors and learning of procedural memories. Next, the use of cutting-edge electrochemical techniques in animal and human studies of BG functioning under normal and disease conditions is discussed. Finally, functional neuroimaging studies are reviewed; these works have shown the relationship between cortico-BG structures activated during DBS and improvement of disease symptoms.

Validity and Efficacy of Screening Algorithms for Assessing Deep Brain Stimulation Candidacy in Parkinson Disease

BACKGROUND

Deep Brain Stimulation (DBS) for Parkinson disease (PD) may be underutilized because of limited access to care (most DBS surgeries are performed at specialized centers) or over-referral of poor candidates, leading to inequitable utilization of limited evaluative resources. There is a pressing need for a widely employable screening algorithm to aid in the evaluation of PD candidates for DBS.

OBJECTIVE

To compare the validity and efficacy of two published screening algorithms, the Florida Surgical Questionnaire for PD and Stimulus, to predict candidacy for DBS.

METHODS

We reviewed the clinical data at our DBS center for 147 consecutive PD DBS referrals between 9/1/2007 and 12/31/2011. Florida Surgical Questionnaire and Stimulus scores were applied retrospectively through a chart review of the Movement Disorder neurologist's initial clinical evaluation. The validity and accuracy of these two algorithms in predicting candidacy for DBS was compared to the decision to offer DBS surgery by our multidisciplinary DBS team.

RESULTS

Of the 130 consecutive PD referrals who presented for initial evaluation, 50 were offered DBS after a standardized multidisciplinary evaluation. The Stimulus scale was a superior screening tool for predicting PD DBS candidacy in these referrals [Area under the Receiver operating curve = 0.8088] compared to the Florida Surgical Questionnaire for PD [Area under the Receiver operating curve = 0.6285].

CONCLUSION

In this single center study, Stimulus was a more appropriate screening measure than the Florida Surgical Questionnaire for PD to assess DBS candidacy for PD.