Towards adaptive deep brain stimulation: clinical and technical notes on a novel commercial device for chronic brain sensing

Abstract

Objective. Technical advances in deep brain stimulation (DBS) are crucial to improve therapeutic efficacy and battery life. We report the potentialities and pitfalls of one of the first commercially available devices capable of recording brain local field potentials (LFPs) from the implanted DBS leads, chronically and during stimulation. The aim was to provide clinicians with well-grounded tips on how to maximize the capabilities of this novel device, both in everyday practice and for research purposes. Approach. We collected clinical and neurophysiological data of the first 20 patients (14 with Parkinson’s disease (PD), five with dystonia, one with chronic pain) that received the Percept™ PC in our centres. We also performed tests in a saline bath to validate the recordings quality. Main results. The Percept PC reliably recorded the LFP of the implanted site, wirelessly and in real time. We recorded the most promising clinically useful biomarkers for PD and dystonia (beta and theta oscillations) with and without stimulation. Furthermore, we provide an open-source code to facilitate export and analysis of data. Critical aspects of the system are presently related to contact selection, artefact detection, data loss, and synchronization with other devices. Significance. New technologies will soon allow closed-loop neuromodulation therapies, capable of adapting stimulation based on real-time symptom-specific and task-dependent input signals. However, technical aspects need to be considered to ensure reliable recordings. The critical use by a growing number of DBS experts will alert new users about the currently observed shortcomings and inform on how to overcome them.

Stimulation related artifacts and a multipurpose template-based offline removal solution for a novel sensing-enabled deep brain stimulation device

“…We demonstrate that sensing LFP signals when stimulation is OFF is not equivalent to sensing when stimulation is ON, which has important implications for both clinical and research applications. Similar to other reports [31,32], simply enabling stimulation (even without delivered current, i.e. the ON-0mA state) introduced artifact not observed when stimulation was OFF.…”

“…Additional artifact (Δ-stimulation artifact) occurred in many subjects when stimulation was being turned ON/OFF (similar to [32]) or the amplitude was changed (Fig. 6).…”

“…SVD was implemented as previously described for ECG removal [25,32]. In brief -epochs of M samples (corresponding to 760 ms, or trimmed as above if epochs overlapped) were extracted at timestamps of ECG incidence (identified by the same technique used with template subtraction).…”

“…Recently, the Medtronic Percept PC became the first FDA approved device with the capability to sense LFPs during stimulation [29]. Preliminary reports have highlighted the presence of ECG artifacts, particularly when stimulation is turned ON [31,32] (ON is a device status setting, and can be configured to deliver no current if amplitude is set to 0 mA). Other sources of artifact included movement artifact and those caused by turning stimulation OFF or ON.…”

“…Artifacts caused by ramping (changing stimulation amplitude), as has been seen with the RC+S [27], have not been previously characterized. Two previous studies (pre-print) have noted the presence of ON-stimulation artifact [31,32] and proposed methods for artifact removal (focusing on ECG), though there has not been a direct comparison of multiple methods. Nor has there been a comprehensive comparison of the LFP signal properties recorded when stimulation is ON versus OFF after artifact removal.…”