Investigating the Correlation Between Gray Matter Volume Changes and Cognitive Function Among Alzheimer's Disease Patients: An MRI-Based Analysis.

Objective: Alzheimer's disease (AD) is a neurodegenerative disease characterized by progressive cognitive impairment and memory dysfunction. This study aims to explore changes of gray matter volume and their relationship with cognitive and memory function in AD patients using magnetic resonance imaging-based analysis.

Methods: This retrospective study analyzed the clinical data from 80 AD patients (AD group) and 45 patients with mild cognitive impairment (MCI group) treated in the hospital between January 2021 and December 2022. Furthermore, 43 healthy adults (control group) were also included for comparison. All the participants underwent a brain magnetic resonance imaging (MRI) examination. These three groups were comparatively analyzed for brain MRI imaging characteristics, changes of gray matter volume, as well as their cognitive and memory functions. Based on gray matter volume, AD patients were divided into the low-volume (37 cases) and high-volume (43 cases) groups using the K-mean clustering method. Furthermore, changes of cognitive and memory function across these two subgroups were compared. The correlation among gray matter volume, cognitive, and memory function across AD patients was assessed using Pearson correlation analysis. Additionally, predictive abilities of gray matter volume in severe cognitive impairment were determined employing receiver operating characteristic (ROC) curve analysis.

Results: The gray matter volume, percentage of gray matter volume, scores of mini-mental state examination (MMSE), and California verbal learning test (CVLT-II) were significantly decreased across the control, MCI, and AD groups (p < 0.05). Compared to the control group, gray matter volume was reduced in the AD and MCI groups. Compared to the high-volume group, gray matter volume, percentage of gray matter volume, scores of MMSE and CVLT-II were decreased in the low-volume group (p < 0.05). Gray matter volume and gray matter volume percentage were positively correlated with scores of MMSE, immediate memory, delayed recall, cue recall, and long-delayed recognition (gray matter volume r = 0.384/0.334/0.308/0.251/0.333; percentage of gray matter volume r = 0.584/0.319/0.299/0.257/0.298; p < 0.001). The area under curve (AUC) for gray matter volume and gray matter volume percentage in predicting severe cognitive impairment were 0.833 (95% CI: 0.747-0.919) and 0.810 (95% CI: 0.715-0.904), respectively (p < 0.001), with sensitivity of 95.24% and 90.48%, and specificity of 66.10% and 67.80%, respectively.

Conclusion: MRI is a useful tool for evaluating changes of gray matter volume in AD patients. The changes in gray matter volume are strongly correlated with cognitive and memory functions, which serve as a reliable predictor of severe cognitive impairment in AD patients. Furthermore, MRI provides robust imaging evidence for identifying AD patients at risk of severe cognitive impairment.