| Abstrakt: |
Background: Diffusion tensor imaging (DTI) measures water diffusion within brain tissue and can provide information regarding white matter, myelin, and axonal degeneration. We analyzed the cingulum bundle of the hippocampus (CBH), chosen for relevance to Alzheimer's Disease (AD) and memory (Wen et al, 2019; Dalboni da Rocha et al, 2020), using fractional anisotropy (FA), radial diffusivity (RD), axial diffusivity (AxD), and mean diffusivity (MD), as well as their relationship to cognition, measured by DTI data from the initial phase of the Korean Brain Aging Study for the Early Diagnosis and Prediction of Alzheimer's Disease (KBASE). Methods: Participants from KBASE included cognitively normal older adults (CN, n = 276), mild cognitive impairment (MCI, n = 142), and AD dementia (AD, n = 87) studied with baseline neuroimaging and cognitive testing at Seoul National University and processed at Indiana University School of Medicine. Affine and non‐linear transformations were used to align individual FA maps to the FMRIB58FA template (FSL). Voxel values were extracted from unilateral CBH regions (determined using JHU ICBM‐DTI‐81‐white‐matter‐labels atlas) and averaged. Univariate‐GLM and Bonferroni‐corrected post‐hoc T‐tests controlling for age and sex were used to analyze diagnostic group differences, with lower FA and higher RD, AxD, and MD values expected in MCI and AD groups compared to CN. Bonferroni‐adjusted partial correlations controlling for age, sex, and education were used to test the hypothesis that DTI values would be associated with worsening cognitive scores. Results: As hypothesized, bilateral CBH DTI values in AD and MCI were significantly worse than those in CN (p<0.001) (Fig 1) with moderate effect sizes (η2 = 0.111 – 0.307). Worsening DTI values were significantly associated with worsening Digit Span Backward, Trailmaking A and B, GDS, MMSE‐KC, CDR‐SB, Word List Recall, and Logical Memory scores at the Bonferroni‐adjusted p‐value of 0.003. Bilaterally, higher Digit Span Forward scores were significantly associated with AxD values and lower Total SMCQ scores were associated with RD, AxD, and MD values. Conclusion: Within the KBASE cohort, MCI and AD demonstrated significantly worse DTI, memory, and cognition consistent with the pattern of white matter microstructural damage previously reported in MCI and AD (Wen et al, 2019; LoBuono et al., 2019). [ABSTRACT FROM AUTHOR] |
