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Schlagwörter:
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Zusammenfassung:
Background: Microstructural abnormalities on diffusion
tensor imaging (DTI) are promising in vivo biomarkers of brain changes associated with the progression of Alzheimer’s Dementia pathology. Recent studies indicate that a decrease of white matter integrity has been found in Mild Cognitive Impairment (MCI) defi ned as a prodromal condition for AD.
Objectives: The present study aimed to investigate
the brain diffusivity changes in MCI quantifi ed as
fractional anisotropy (FA) and mean diffusivity (MD),
and to evaluate if the changes in white matter diffusivity
are related to linguistic and semantic memory processes.
Methods: Eighteen healthy elderly and 22 MCI patients
were enrolled in this study. All participants underwent
3T MRI exam for diffusion tensor based white matter investigation and cognitive tests of visual naming, naming from definition, categorical fluency and reading for objects, actions and famous people, and words-association. The comparison of FA and MD between groups and correlations between them and cognitive performance in MCI were carried
out.
Results: There were no group differences in FA, but there was a hemispheric lateralization effect, such as a decreased FA on the right hemisphere compared to the left one. Compared to healthy elderly, MCI patients showed a reduced mean FA in the right inferior longitudinal fasciculus (ILF) and elevated MD in the uncinate
fasciculus (UNC), suggestive of a neuronal loss in these tracts. Moreover, the FA of the ILF correlated with the reading of action performance, confirming
the role of ILF in language and visual identification
processes.
Conclusions: Our findings evidenced that MCI presents white matter diffusivity alterations in ILF and UNC, which might underling cognitive impairment. Across the linguistic and semantic variables, reading of action appeared to be related to ILF FA, forthcoming studies will encompass also other cognitive abilities.
