System-wise balance evaluation and its association with structural brain changes in Parkinson's disease.

Background: Balance dysfunction in Parkinson's disease (PD) involves complex mechanisms beyond simple reflex impairment. Common clinical assessments, such as the pull test, lack multidimensional evaluation and are not optimized for quantifying balance impairment. In contrast, the Mini Balance Evaluation Systems Test (MiniBESTest) can assess balance dysfunction from multiple perspectives, offering a more comprehensive and quantitative assessment.

Objective: This study aimed to explore the neural correlates of balance dysfunction in PD by examining the association between MiniBESTest scores and structural brain changes using voxel-based morphometry (VBM).

Methods: Fifty patients with PD who met the study criteria were evaluated by MiniBESTest, clinical assessment, and MRI. VBM regression analysis was conducted to assess the associations between the MiniBESTest scores and the cortical gray matter volumes.

Results: Significant correlations were observed between total MiniBESTest scores and atrophy from the superior temporal gyrus (STG) to the insular cortex. Element-specific analyses indicated that Subscore II (reactive postural control) was associated with atrophy confined to the left STG, while Subscore IV (dynamic gait) correlated with atrophy across the precentral cortex and temporoparietal junction.

Conclusion: We identified structural changes of the brain based on a multidimensional evaluation of balance dysfunction. A strong correlation was observed between atrophy in the STG and balance dysfunction in PD, highlighting this region's role in dynamic postural control and related symptoms.