Real-world chronic recordings from implantable adaptive deep brain stimulation systems for Parkinson's disease motor state classification.

INTRODUCTION

Precise identification of motor states in Parkinson's disease (PD) is critical for adaptive deep brain stimulation (aDBS) therapies. Recent developments in implantable neurostimulators now support continuous neural recordings, enabling long-term monitoring of PD-related neural dynamics under real-world conditions. However, the real potential of such deep brain continuous recordings in chronic home-based conditions has not been explored yet. In this work, we introduce a multimodal classification framework that integrates subthalamic nucleus local field potentials (STN-LFPs), wearable sensors, and patient-reported diaries to distinguish between three key motor states: ON, OFF, and SLEEP.

METHODS

The framework was initially validated on data collected from three patients over an average of 30 days (totaling 2,136 h of LFP recordings), and then applied to a larger dataset from thirteen patients recorded over an average of 14 days (totaling 4,440 h of LFP recordings). Feature extraction was performed in the time, frequency and time-frequency domains, after applying principal component analysis (PCA) to decrease dimensionality, which preserved 95% of the variance of the data and reduced computational complexity.

RESULTS

The multilayer perceptron (MLP) classifier using time-frequency domain features achieved the highest F1-score among the models tested. For the three validation patients, the MLP reached F1-scores of 81.1% with wearable sensor data and 94.3% with diary-derived data. When evaluated across all thirteen patients, it maintained a strong F1-score of 93.1% using diary time-frequency features.

DISCUSSION: These results demonstrate that chronic LFP recordings available 24/7 from implantable aDBS devices enable robust motor state classification, thus supporting the personalization and optimization of aDBS systems for real-life use.