Estimation of Beta Burst Durations from Subthalamic Nucleus Local Field Potentials in Parkinson’s Disease Through Hilbert and Continuous Wavelets Transforms

Parkinson’s disease (PD) has a high impact on motor and cognitive impairment. Recent studies have suggested that abnormal beta band activity (13–35 Hz) in local field potentials (LFP) within the Subthalamic Nucleus (STN) are associated with PD’s symptoms. Moreover, these oscillations are characterized by non-stationary behavior throughout the LFP defined as beta bursts. Despite of the currently widespread framework for evaluating beta bursts based on Continuous Wavelet Transform (CWT) coefficients, a carefully methodological investigation is required, especially when dealing with shorter intraoperative recordings in the context of deep brain stimulation (DBS). Aiming to investigate methodological dependence in beta burst detection, this work presents a comparison between wavelets analysis vs. Hilbert Transform (HT) magnitude for beta bursts duration evaluation considering different percentiles thresholds. Signals from 17 hemispheres of 12 tremor dominant PD patients undergoing stereotaxic surgery under rest and movement conditions were investigated. Bursts durations evaluated by both methods were capable of detecting significant differences between rest vs. movement conditions, depending on the adopted percentile threshold. These results point to a better comprehension of beta burst activity under daily motor tasks as also reveals a methodological dependence on burst characterization, being the HT method more prone to detect beta bursts with shorter durations in contrast to CWT.