REVIEW URRENT C OPINION
Deep brain stimulation for movement disorders: 2015 and beyond Alfonso Fasano a and Andres M. Lozano b
Purpose of review The purpose of this review was to review the recent and future developments of deep brain stimulation (DBS) for movement disorders. Recent findings In the last 2 years, we have gained a better understanding of established indications, particularly with respect to the debate on whether subthalamus or globus pallidus pars interna should be the target of choice for Parkinson’s disease. In addition, the role of DBS for dystonia has been further defined in terms of patients’ selection and outcome of surgery. Other established (e.g. essential tremor) and novel indications (e.g. Tourette syndrome) have been addressed. Along with the evolving knowledge of the clinical aspects of DBS, technological advances are also shaping the present and the future of DBS. New implantable pulse generators (e.g. allowing storage of electrophysiological data and eventual adaptive stimulation) as well as new electrode configurations are now available. Furthermore, high-resolution structural imaging, including high-field MRI and diffusion tensor tractography, will facilitate both the planning of DBS procedures, and the optimization of postoperative outcomes by aiding stimulation programming. Summary The recent successes of DBS along the clinical and technological directions are changing the current practice of neuromodulation and, more importantly, will also drive future developments of this fascinating treatment. Keywords deep brain stimulation, movement disorders, Parkinson’s disease, technology
INTRODUCTION Two years ago the 25th anniversary of deep brain stimulation (DBS) in the modern era was celebrated. Almost 3 decades after the first clinical experience [1], DBS has become widely accepted as a treatment for Parkinson’s disease, dystonia and tremor and as an off-label treatment for many other movement disorders. To date, more than 100 000 patients have undergone DBS surgery [2]. DBS field is expanding exponentially along two directions: clinical and technological. We have achieved a deeper understanding of outcomes, thus facilitating the process of target and patient’s selection; on the other hand, the advance of technologies has provided clinicians with new tools making targeting, programming and overall management easier. These two directions are not mutually exclusive but are the most recent advantages of neuromodulation and they have opened new avenues toward new targets and indications. This review will focus on the recent successes of DBS along the aforementioned clinical and
technological directions and will also draw the possible scenarios for the future developments of this fascinating treatment.
SEARCH STRATEGY AND SELECTION CRITERIA Literature for this review was identified from a PubMed search (http://www.ncbi.nlm.nih.gov/ pubmed/) from 1 January 2014 up to 4 April 2015 a
Morton and Gloria Shulman Movement Disorders Clinic and the Edmond J. Safra Program in Parkinson’s Disease, Toronto Western Hospital and Division of Neurology, UHN, Division of Neurology and b Division of Neurosurgery, Toronto Western Hospital, University Health Network, Department of Surgery, University of Toronto, Toronto, Ontario, Canada Correspondence to Dr Alfonso Fasano, Movement Disorders Centre – Toronto Western Hospital, 399 Bathurst St, 7 Mc412, Toronto, ON, Canada M5T 2S8. Tel: +1 416 603 5800 ext. 5961; fax: +1 416 603 5004; e-mail: [email protected] Curr Opin Neurol 2015, 28:423–436 DOI:10.1097/WCO.0000000000000226
1350-7540 Copyright ß 2015 Wolters Kluwer Health, Inc. All rights reserved.
www.co-neurology.com
Copyright © 2015 Wolters Kluwer Health, Inc. All rights reserved.
Movement disorders
KEY POINTS
improvement of signs responding to dopaminergic drugs, whereas unresponsive features often predominate in the late stages of the disease [5 ]; second, older patients are more likely to develop surgical complication and/or worsening of axial motor functions [6]; third, performing DBS at advanced stages of illness can alleviate certain aspects of motor dysfunction without addressing the ongoing difficulties in well-being and social relations with themselves, spouses, families and socio-professional environment [7]. The aforementioned concepts have been examined in the Earlystim trial [8 ], a multicenter 2-year prospective study comparing the best medical treatment with DBS of subthalamic nucleus (STN) in 251 patients with early occurrence of motor fluctuation (mean disease duration: 7 years). This trial found an early and sustained improvement of quality of life in patients receiving DBS but has also started a debate on the clinical meaning and practicability of such an approach, particularly questioning the use of best medical treatment as a comparator [9]. An ongoing large Chinese trial (NCT01922388) has been designed to compare the outcome of STN DBS in patients with Parkinson’s disease with motor complication for longer or shorter than 3 years. Others have proposed STN DBS in patients without motor fluctuation (disease duration
Deep brain stimulation for movement disorders: 2015 and beyond Alfonso Fasano a and Andres M. Lozano b
Purpose of review The purpose of this review was to review the recent and future developments of deep brain stimulation (DBS) for movement disorders. Recent findings In the last 2 years, we have gained a better understanding of established indications, particularly with respect to the debate on whether subthalamus or globus pallidus pars interna should be the target of choice for Parkinson’s disease. In addition, the role of DBS for dystonia has been further defined in terms of patients’ selection and outcome of surgery. Other established (e.g. essential tremor) and novel indications (e.g. Tourette syndrome) have been addressed. Along with the evolving knowledge of the clinical aspects of DBS, technological advances are also shaping the present and the future of DBS. New implantable pulse generators (e.g. allowing storage of electrophysiological data and eventual adaptive stimulation) as well as new electrode configurations are now available. Furthermore, high-resolution structural imaging, including high-field MRI and diffusion tensor tractography, will facilitate both the planning of DBS procedures, and the optimization of postoperative outcomes by aiding stimulation programming. Summary The recent successes of DBS along the clinical and technological directions are changing the current practice of neuromodulation and, more importantly, will also drive future developments of this fascinating treatment. Keywords deep brain stimulation, movement disorders, Parkinson’s disease, technology
INTRODUCTION Two years ago the 25th anniversary of deep brain stimulation (DBS) in the modern era was celebrated. Almost 3 decades after the first clinical experience [1], DBS has become widely accepted as a treatment for Parkinson’s disease, dystonia and tremor and as an off-label treatment for many other movement disorders. To date, more than 100 000 patients have undergone DBS surgery [2]. DBS field is expanding exponentially along two directions: clinical and technological. We have achieved a deeper understanding of outcomes, thus facilitating the process of target and patient’s selection; on the other hand, the advance of technologies has provided clinicians with new tools making targeting, programming and overall management easier. These two directions are not mutually exclusive but are the most recent advantages of neuromodulation and they have opened new avenues toward new targets and indications. This review will focus on the recent successes of DBS along the aforementioned clinical and
technological directions and will also draw the possible scenarios for the future developments of this fascinating treatment.
SEARCH STRATEGY AND SELECTION CRITERIA Literature for this review was identified from a PubMed search (http://www.ncbi.nlm.nih.gov/ pubmed/) from 1 January 2014 up to 4 April 2015 a
Morton and Gloria Shulman Movement Disorders Clinic and the Edmond J. Safra Program in Parkinson’s Disease, Toronto Western Hospital and Division of Neurology, UHN, Division of Neurology and b Division of Neurosurgery, Toronto Western Hospital, University Health Network, Department of Surgery, University of Toronto, Toronto, Ontario, Canada Correspondence to Dr Alfonso Fasano, Movement Disorders Centre – Toronto Western Hospital, 399 Bathurst St, 7 Mc412, Toronto, ON, Canada M5T 2S8. Tel: +1 416 603 5800 ext. 5961; fax: +1 416 603 5004; e-mail: [email protected] Curr Opin Neurol 2015, 28:423–436 DOI:10.1097/WCO.0000000000000226
1350-7540 Copyright ß 2015 Wolters Kluwer Health, Inc. All rights reserved.
www.co-neurology.com
Copyright © 2015 Wolters Kluwer Health, Inc. All rights reserved.
Movement disorders
KEY POINTS
improvement of signs responding to dopaminergic drugs, whereas unresponsive features often predominate in the late stages of the disease [5 ]; second, older patients are more likely to develop surgical complication and/or worsening of axial motor functions [6]; third, performing DBS at advanced stages of illness can alleviate certain aspects of motor dysfunction without addressing the ongoing difficulties in well-being and social relations with themselves, spouses, families and socio-professional environment [7]. The aforementioned concepts have been examined in the Earlystim trial [8 ], a multicenter 2-year prospective study comparing the best medical treatment with DBS of subthalamic nucleus (STN) in 251 patients with early occurrence of motor fluctuation (mean disease duration: 7 years). This trial found an early and sustained improvement of quality of life in patients receiving DBS but has also started a debate on the clinical meaning and practicability of such an approach, particularly questioning the use of best medical treatment as a comparator [9]. An ongoing large Chinese trial (NCT01922388) has been designed to compare the outcome of STN DBS in patients with Parkinson’s disease with motor complication for longer or shorter than 3 years. Others have proposed STN DBS in patients without motor fluctuation (disease duration
