Multimodal mapping of balance dysfunction in Parkinson's disease: a consensus roadmap for research and intervention

Balance depends on accurate perception of self-motion and verticality and on multisensory integration for stance, and gait. In Parkinson's disease, balance is commonly impaired and variably affected by treatment. Although vestibular and multisensory contributions are increasingly recognized, progress is limited by fragmented evidence, inconsistent methods, and artifact-prone measures. We provide a consensus roadmap across four domains - video-oculography/vHIT, VEMPs, posturography, and perceptual paradigms - to improve clinical translation of balance research in Parkinson's disease.

An interdisciplinary taskforce conducted a comprehensive literature review and a modified Delphi process (≥80% agreement), using virtual meetings, surveys, and an in-person consensus session. Oculography/vHIT shows largely preserved aVOR in Parkinson's disease but is vulnerable to Parkinson's disease specific artifacts, requiring standardization. VEMPs relate to brainstem and non-motor features but are limited by EMG-dependent confounds. Posturography reveals impaired multisensory integration with visual dependence and cholinergic contributions; reactive-capacity measures outperform sway alone. Perceptual paradigms show task-specific distortions and increased variability linked to axial/postural syndromes.

This consensus offers a practical roadmap, de-emphasize aVOR/vHIT as primary unsteadiness outcomes; use VEMPs as ancillary measures; prioritize posturography probing adaptability and reactive stepping; integrate wearables and neurochemical imaging; and adopt consortium-level minimum datasets to enable reproducible, phenotype-aware advances in Parkinson's disease balance research.