03 | Adaptation strategies and neurophysiological response in early-stage Parkinson's disease: BioVRSea approach

Altered postural control is one of the earliest manifestations of Parkinson’s disease (PD) and is strongly linked to fall risk,1,2 yet its neurophysiological underpinnings remain insufficiently characterized. This study employed BioVRSea, an immersive virtual-reality paradigm combined with platform motion, to assess balance responses in early-stage PD patients and healthy controls. Thirty-eight participants (9 PD, 29 healthy) were exposed to visual and motor perturbations while electroencephalography (EEG), electromyography (EMG), heart rate, and center of pressure (CoP) signals were recorded. Analyses focused on the PRE (before platform-motor stimulation) and POST (after platform-motor stimulation) phases to capture adaptive postural responses. Results revealed clear group differences: PD participants exhibited altered CoP sway dynamics,3 distinct neuromuscular signatures in tibialis anterior and soleus muscles,4 and reduced cortical activation in theta and alpha bands.5,6 These findings suggest that early-stage PD is characterized by both central and peripheral impairment in balance regulation. The BioVRSea approach demonstrates its potential as a multimodal framework to uncover early postural control alterations in PD. By combining neural, muscular, and biomechanical features, this method may contribute to the development of quantitative biomarkers, improving early diagnosis and supporting targeted interventions for balance dysfunction in PD. Ethics statement: All participants received detailed written information about the study and provided their signed informed consent. The research was conducted in accordance with the principles embodied in the Declaration of Helsinki and Icelandic statutory requirements. The study protocol was approved by the Icelandic National Bioethics Committee (no: VSN-20–101).