Link of gray matter volume to cognitive and motor function in elderly patients with mild cognitive impairment.

Background: Mild cognitive impairment (MCI) is a transitional state between normal aging and Alzheimer's disease (AD), characterized by subtle cognitive decline. Amnestic MCI (aMCI), in particular, is a critical precursor often progressing to AD. There is growing interest in understanding the neuroanatomical correlates of aMCI, especially the role of gray matter volume (GMV) in cognitive and motor function decline. This study hypothesized that aMCI patients will exhibit reduced GMV, particularly in brain regions associated with cognition and motor control, impacting both cognitive performance and motor abilities.

Aim: To investigate the association of GMV with cognitive and motor functions in aMCI.

Methods: In this cross-sectional study conducted from March 2022 to March 2024, 45 aMCI patients and 45 normal controls from our Department of Geratology were enrolled. Voxel-based morphometry was used to compare GMV between groups. Correlation of differential GMV with cognitive scores and gait parameters was assessed via partial correlation analysis. Linear regression was used to assess associations between whole-brain GMV and gait measures.

Results: GMV of aMCI region of interest (ROI) 1 and ROI2 was negatively correlated with Activities of Daily Living (ADL) score. GMV of ROI6 was positively correlated with the total scores of Mini-Mental State Examination and Cambridge Cognitive Examination-Chinese Version (CAMCOG-C) and negatively correlated with ADL score. In the partial correlation analysis of cognitive and motor function parameters, age, gender, educational level, height, and weight were controlled, and the results showed that CAMCOG-C was negatively correlated with Dual Task of Time Up and Go Test (TUG) duration in the aMCI group. The volume of the left occipital gray matter in the aMCI group was negatively correlated with TUG. GMV of the bilateral frontal gyrus, right orbitofrontal gyrus, right occipital cleft, right supraoccipital gyrus, and left anterior central gyrus was positively correlated with walking speed.

Conclusion: GMV reduction in aMCI correlates with impaired cognition and motor function, emphasizing key roles for prefrontal, occipital, and central regions in gait disorders.