High-frequency conductivity was negatively associated with myelin water fraction in the brain of cognitive impairments

Background Alzheimer’s disease (AD) and mild cognitive impairment (MCI) are associated with cognitive decline and brain changes, including gray and white matter atrophy. High-frequency conductivity (HFC) and myelin water fraction (MWF) serve as potential biomarkers for these neurological changes. Purpose To evaluate the relationship between HFC and myelin-related metrics (MWF and white matter volume (WMV)) in the context of cognitive decline. Materials and methods This cross-sectional prospective study included 170 participants who were differentially diagnosed as 42 cognitively unimpaired (CU) older participants, 84 with amnestic MCI, and 44 with clinically diagnosed probable AD of mild to moderate severity. MRI techniques were used to measure HFC, MWF, and WMV across defined regions of interest that were (1) voxels with a WMV value greater than 1% and an MWF value greater than 1% (whole brain), (2) the hippocampus, (3) the insula, and (4) the thalamus in each participant. Statistical methods included correlations between these indices and clinical measures, multiple regression analyses of HFC with other MRI indices, and receiver operating characteristic (ROC) curve analysis. Results The robust multiple regression analyses showed that HFC was negatively associated with MWF in the whole-brain, hippocampal, and insular ROIs. Associations between HFC and WMV were region-specific, with a negative association in the whole-brain ROI and a positive association in the insula. Probable AD showed higher HFC in the whole-brain, hippocampal, and thalamic ROIs, while group differences in MWF and WMV were region-specific. Conclusion Lower apparent MWF was associated with higher HFC, suggesting a relationship between tissue microstructural alterations and conductivity. Further research is needed to validate these findings in diverse populations.