Negative emotion modulates postural tremor variability in Parkinson's disease: A multimodal EEG and motion sensor study toward behavioral interventions.

Background: Despite clinical observations of emotion-tremor interactions in Parkinson's disease (PD), the neurophysiological mechanisms mediating this relationship remain poorly characterized. Methods: This study employs a multimodal approach integrating 16-channel electroencephalography (EEG) and inertial motion sensors to investigate emotion-modulated postural tremor dynamics in 20 PD patients and 20 healthy controls (HCs) during standardized video-induced emotional states (positive/neutral/negative). Results: Key findings demonstrate impaired negative emotional processing in PD, manifested as paradoxical increases in subjective valence (pleasure-displeasure ratings) coupled with reduced physiological arousal. Tremor variability predominantly correlated with negative emotional states, showing a negative association with valence scores and positive correlation with arousal levels. EEG analysis identified differential beta-band power modulation in prefrontal (Fp1/Fp2) and temporal (T3/T4) regions during negative emotion processing. These results suggest that emotion-driven tremor fluctuations in PD originate from dysfunctional integration of limbic and motor networks. Conclusion: These findings establish emotion-modulated tremor as a distinct PD phenotype, informing the development of closed-loop biofeedback systems for personalized neuromodulation.