Spectral characteristics of subthalamic nucleus local field potentials in Parkinson's disease: Phenotype and movement matter

Abstract

Parkinson's disease (PD) is clinically heterogeneous across patients and may be classified in three motor phenotypes: tremor dominant (TD), postural instability and gait disorder (PIGD), and undetermined. Despite the significant clinical characterization of motor phenotypes, little is known about how electrophysiological data, particularly subthalamic nucleus local field potentials (STN‐LFP), differ between TD and PIGD patients. This is relevant since increased STN‐LFP bandpower at α–β range (8–35 Hz) is considered a potential PD biomarker and, therefore, a critical setpoint to drive adaptive deep brain stimulation. Acknowledging STN‐LFP differences between phenotypes, mainly in rest and movement states, would better fit DBS to clinical and motor demands. We studied this issue through spectral analyses on 35 STN‐LFP in TD and PIGD patients during rest and movement. We demonstrated that higher β2 activity (22–35 Hz) was observed in PIGD only during rest. Additionally, bandpower differences between rest and movement occurred at the α–β range, but with different patterns as per phenotypes: movement‐induced desynchronization concerned lower frequencies in TD (10–20 Hz) and higher frequencies in PIGD patients (21–28 Hz). Finally, when supervised learning algorithms were employed aiming to discriminate PD phenotypes based on STN‐LFP bandpower features, movement information had improved the classification accuracy, achieving peak performances when TD and PIGD movement‐induced desynchronization ranges were considered. These results suggest that STN‐LFP β‐band encodes phenotype‐movement dependent information in PD patients.

Differential Effects of Pathological Beta Burst Dynamics Between Parkinson’s Disease Phenotypes Across Different Movements

“…The differences observed in our study between AR and TD may reflect differences in these STN-cortical interactions. This is further supported by the previous work demonstrating greater high beta power in freezers compared to non-freezers ( Toledo et al, 2014 ) and tremor-dominant vs. akinetic-rigid ( Godinho et al, 2021 ) at rest. Together, these results point to a pathological low beta oscillation that is consistent across phenotypes and then a potentially separate high beta oscillation that may be more specific to akinetic-rigid symptoms regardless of task.…”

“…Previous studies that have evaluated phenotype differences primarily focused on high (20–35 Hz) and low (10–20 Hz) beta band power in the operating room or perioperative state (i.e., the week after implantation). Differences in high beta band power were demonstrated between tremor-dominant (TD) and akinetic-rigid (AR) phenotypes at rest, but not during movement in an elbow-flexion task in the operating room ( Godinho et al, 2021 ). Furthermore, within band differences between rest and movement were observed for each phenotype (low beta for tremor-dominant and high beta for akinetic-rigid).…”

Subthalamic Peak Beta Ratio Is Asymmetric in Glucocerebrosidase Mutation Carriers With Parkinson's Disease: A Pilot Study

“…tremor dominant PD vs. postural instability gait disorder phenotypes. Godinho et al (2021) found that supervised learning algorithms aimed at discriminating PD phenotypes based on STN-LFP band power features were most accurate when tremor dominant and postural instability gait disorder movement-induced desynchronization ranges were considered (41). Future studies can employ such algorithms and include genotype to improve phenotypic classification using physiologic signals.…”

Differential Effects of Pathological Beta Burst Dynamics Between Parkinson’s Disease Phenotypes Across Different Movements

“…Previous studies that have evaluated phenotype differences primarily focused on high and low beta band power in the operating room or perioperative state (i.e., the week after implantation). Differences in high beta band power were demonstrated between tremordominant and akinetic-rigid subtypes at rest, but not during movement in an elbowflexion task in the operating room (Godinho et al, 2021). Furthermore, within band differences between rest and movement were observed for each subtype (low beta for tremor dominant, high beta for akinetic rigid).…”