White matter changes in cognitively intact older adults with informant ratings of cognitive decline

Abstract

Previously we found that white matter measure is more sensitive than gray matter measure to changes in cognitive function in a group of early mild cognitive impairment. In the present study, we aimed to investigate the putative changes in diffusivity in cognitively intact older adults with or without informant endorsing decline. Twenty-nine cognitively intact older adults with informant ratings of memory decline and 22 cognitively intact older adults without informant ratings of memory decline were included in this study. The groups were matched in age, education, sex distribution, frequency of apolipoprotein E (APOE) ε4 carriers, scores on the Geriatric Depression Scale, and scores on a self-rating memory questionnaire. All participants were tested with a comprehensive cognitive battery and underwent MRI to investigate their integrity of regional gray matter and segments of the cingulum bundle with Diffusion Spectrum Imaging tract-specific analysis. The results revealed that the two groups did not show significant difference in measures of memory function and medial temporal gray matter. However, the informant ratings of memory decline group showed significantly lower generalized fractional anisotropy values in right posterior cingulum and bilateral inferior cingulum bundles relative to their counterparts. Informants’ perceptions of participants’ everyday functioning and memory changes were related to the participants’ cingulate white matter changes, and the information may provide a useful and empirical method for identifying individuals at higher risk of future dementia.