Where Are We with Deep Brain Stimulation? A Review of Scientific Publications and Ongoing Research

Abstract

<b><i>Background:</i></b> Deep brain stimulation (DBS) is a neuromodulatory technique that delivers adjustable electrical stimuli to brain targets to relieve symptoms associated with dysregulated neural circuitry. Over the last several decades, DBS has been applied to a number of conditions, including motor, pain, mood, and cognitive disorders. An assessment of the body of work in this field is warranted to determine where we have been, define the current state of the field, and chart a path toward the future. <b><i>Objective:</i></b> The aim of the study was to assess the state of DBS-related research by analyzing the DBS literature as well as active studies sponsored by the National Institutes of Health (NIH) or German Research Foundation (Deutsche Forschungsgemeinschaft [DFG]). <b><i>Methods:</i></b> Peer-reviewed DBS publications were extracted from PubMed. Active NIH-funded DBS projects were extracted from the RePORT database and active DFG projects from the German Research Foundation database. Records were analyzed using custom-developed algorithms to generate a detailed overview of past and present DBS-related research. Specifically, records were categorized by publication year, journal, language, country of origin, contributing authors, disorder, brain target, study design, and topic. Expected project duration and costs were also provided for active studies. <b><i>Results:</i></b> In total, 8,974 publications, 172 active NIH-funded projects, and 34 active DFG projects were identified. Records spanned 52 different disorders across 31 distinct brain targets and showed a recent shift toward studies examining conditions other than movement disorders. Most published works involved human research (80.6% of published studies), of which 10.2% were identified as clinical trials. Increasingly, studies focused on imaging or electrophysiological changes associated with DBS (69.8% NIH-active and 70.6% DFG-active vs. 25.8% published) or developing new stimulation techniques and adaptive technologies (37.8% NIH-active and 17.6% DFG-active vs. 6.5% published). <b><i>Conclusions:</i></b> This overview of past and present DBS-related studies provides insight into the status of DBS research and what we can anticipate in the future concerning new indications, improved/novel target selection and stimulation paradigms, closed-loop technology, and a better understanding of the mechanisms of action of DBS.