Approaches to closed-loop deep brain stimulation for movement disorders

Abstract

<jats:sec><jats:title>OBJECTIVE</jats:title><jats:p>Deep brain stimulation (DBS) is a safe and effective therapy for movement disorders, such as Parkinson’s disease (PD), essential tremor (ET), and dystonia. There is considerable interest in developing “closed-loop” DBS devices capable of modulating stimulation in response to sensor feedback. In this paper, the authors review related literature and present selected approaches to signal sources and approaches to feedback being considered for deployment in closed-loop systems.</jats:p></jats:sec><jats:sec><jats:title>METHODS</jats:title><jats:p>A literature search using the keywords “closed-loop DBS” and “adaptive DBS” was performed in the PubMed database. The search was conducted for all articles published up until March 2018. An in-depth review was not performed for publications not written in the English language, nonhuman studies, or topics other than Parkinson’s disease or essential tremor, specifically epilepsy and psychiatric conditions.</jats:p></jats:sec><jats:sec><jats:title>RESULTS</jats:title><jats:p>The search returned 256 articles. A total of 71 articles were primary studies in humans, of which 50 focused on treatment of movement disorders. These articles were reviewed with the aim of providing an overview of the features of closed-loop systems, with particular attention paid to signal sources and biomarkers, general approaches to feedback control, and clinical data when available.</jats:p></jats:sec><jats:sec><jats:title>CONCLUSIONS</jats:title><jats:p>Closed-loop DBS seeks to employ biomarkers, derived from sensors such as electromyography, electrocorticography, and local field potentials, to provide real-time, patient-responsive therapy for movement disorders. Most studies appear to focus on the treatment of Parkinson’s disease. Several approaches hold promise, but additional studies are required to determine which approaches are feasible, efficacious, and efficient.</jats:p></jats:sec>

Clinical applications of neurochemical and electrophysiological measurements for closed-loop neurostimulation

“…to 50% improvement in United Parkinson's Disease Rating Scale III (UPDRS-III) scores compared to 30% improvement with open-loop DBS. 5,6 Further, total stimulation time by the closed-loop system was comparatively reduced, by 44%. Battery drain is a significant concern with always-on approaches to DBS, as the constant power drain necessitates periodic replacement of the battery, which exposes the patient to repeated surgeries and infection risks.…”

Deep brain stimulation for Tourette’s syndrome

“…At present, most DBS systems function in an 'open-loop' mode, that is, the stimulation parameters are preset in advance and cannot be changed or updated according to the clinical symptoms of the patient or to underlying pathophysiological changes in the brain. The classical open-loop system, however, represents a static approach to therapy within an inherently dynamic system [74]. In contrast, responsive or adaptive DBS (aDBS) is designed to function as a 'closed-loop' stimulation device, which can be personalized according to the frequency and duration of a physiologic event or behavioral manifestation [59,[75][76][77][78].…”

From Emotions to Mood Disorders: A Survey on Gait Analysis Methodology

“…Application of DBS at the subthalamic nucleus and ventral striatum showed improvement in both gait performance and emotional states and it has been suggested as a way to treat gait problems that link with mood disorders [12]. However, the effects of DBS are heterogeneous and depend critically on the site of delivery and the dose with relation to the underline neurotransmitters [12], [114], [115]. These evidences suggest the use of adaptive DBS solutions based on implanted devices to facilitate more targeted therapy [115], [116].…”

“…However, the effects of DBS are heterogeneous and depend critically on the site of delivery and the dose with relation to the underline neurotransmitters [12], [114], [115]. These evidences suggest the use of adaptive DBS solutions based on implanted devices to facilitate more targeted therapy [115], [116]. Invasive approaches involve implanted sensing devices that measure subcortical local field potentials and/or neurotransmitters such as dopamine.…”

“…Invasive approaches involve implanted sensing devices that measure subcortical local field potentials and/or neurotransmitters such as dopamine. On the other hand, kinematic, EMG and electrocorticography data have been suggested as non-invasive biomarkers that could also drive DBS [115], [117], [118].…”