Subthalamic low beta bursts differ in Parkinson's disease phenotypes

lObjective: Parkinson's disease (PD) patients may be categorized into tremor-dominant (TD) and postural-instability and gait disorder (PIGD) motor phenotypes, but the dynamical aspects of subthalamic nucleus local field potentials (STN-LFP) and the neural correlates of this phenotypical classification remain unclear.Methods: 35 STN-LFP (20 PIGD and 15 TD) were investigated through continuous wavelet transform and machine-learning-based methods. The beta oscillation - the main band associated with motor impair-ment in PD - dynamics was characterized through beta burst parameters across phenotypes and burst intervals under specific proposed criteria for optimal burst threshold definition.Results: Low-frequency (13-22 Hz) beta burst probability was the best predictor for PD phenotypes (75% accuracy). PIGD patients presented higher average burst duration (p = 0.018), while TD patients exhibited higher burst probability (p = 0.014). Categorization into shorter and longer than 400 ms bursts led to sig-nificant interaction between burst length categories and the phenotypes (p < 0.050) as revealed by mixed-effects models. Long burst durations and short bursts probability positively correlated, respec-tively, with rigidity-bradykinesia (p = 0.029) and tremor (p = 0.038) scores.Conclusions: Subthalamic low-frequency beta bursts differed between TD and PIGD phenotypes and cor-related with motor symptoms.

Automated summary

This study investigated the dynamics of subthalamic nucleus local field potentials (STN-LFP) in Parkinson's disease patients and found differences in low-frequency beta bursts between tremor-dominant and postural instability and gait disorder phenotypes. These differences were correlated with motor symptoms.