Analysis and visualisation of tremor dynamics in deep brain stimulation patients

Rene Peter Bremm,Frank Hertel,Klaus Peter Koch,Rejko Krüger,Jorge Gonçalves

doi:10.1515/cdbme-2020-3030

Abstract

Abstract Deep brain stimulation (DBS) is an established therapy for movement disorders such as in Parkinson's disease (PD) and essential tremor (ET). Adjusting the stimulation parameters, however, is a labour-intensive process and often requires several patient visits. Physicians prefer objective tools to improve (or maintain) the performance in DBS. Wearable motion sensors (WMS) are able to detect some manifestations of pathological signs, such as tremor in PD. However, the interpretation of sensor data is often highly technical and methods to visualise tremor data of patients undergoing DBS in a clinical setting are lacking. This work aims to visualise the dynamics of tremor responses to DBS parameter changes with WMS while patients performing clinical hand movements. To this end, we attended DBS programming sessions of two patients with the aim to visualise certain aspects of the clinical examination. PD tremor and ET were effectively quantified by acceleration amplitude and frequency. Tremor dynamics were analysed and visualised based on setpoints, movement transitions and stability aspects. These methods have not yet been employed and examples demonstrate how tremor dynamics can be visualised with simple analysis techniques. We therefore provide a base for future research work on visualisation tools in order to assist clinicians who frequently encounter patients for DBS therapy. This could lead to benefits in terms of enhanced evaluation of treatment efficacy in the future.

Highlights

Pathological tremor is typically more pronounced at the upper limbs in patients with movement disorders such as Parkinson's disease (PD) and essential tremor (ET) [1]
A motor task is defined as resting position (RP) when the arm/hand is lying on the table, as a postural position (PP) when the arm/hand is outstretched, and as FTN when touching the nose with the index finger
Set-points: The aim was to the find the setpoints in RP, PP and FTN motor tasks for each disease group and to fine-tune the Deep brain stimulation (DBS) parameters in each setpoint

Summary

Introduction

Pathological tremor is typically more pronounced at the upper limbs in patients with movement disorders such as PD and ET [1]. A series of visually guided hand movements (i.e. motor tasks) enable the physician to assess the severity of the motor symptoms and to adjust the DBS parameters [3]. This clinical evaluation is based on the observation of the tremor waveform, which is hard to detect visually for a precise DBS adaptation [4]. Methods to visualise tremor data of patients with DBS in a clinical setting are lacking

Objectives

Methods

Results