title: Mild cognitive impairment, poor episodic memory, and late-life depression are associated with cerebral cortical thinning and increased white matter hyperintensities.
abstract: In various independent studies to date, cerebral cortical thickness and white matter hyperintensity (WMH) volume have been associated with episodic memory, depression, and mild cognitive impairment (MCI). The aim of this study was to uncover variations in cortical thickness and WMH volume in association with episodic memory, depressive state, and the presence of MCI simultaneously in a single study population. The participants were 186 individuals with MCI (clinical dementia rating [CDR] of 0.5) and 136 healthy elderly controls (HCs; CDR of 0) drawn from two community-based cohort studies in northern Japan. We computed cerebral cortical thickness and WMH volume by using MR scans and statistically analyzed differences in these indices between HCs and MCI participants. We also assessed the associations of these indices with memory performance and depressive state in participants with MCI. Compared with HCs, MCI participants exhibited thinner cortices in the temporal and inferior parietal lobes and greater WMH volumes in the corona radiata and semioval center. In MCI participants, poor episodic memory was associated with thinner cortices in the left entorhinal region and increased WMH volume in the posterior periventricular regions. Compared with non-depressed MCI participants, depressed MCI participants showed reduced cortical thickness in the anterior medial temporal lobe and gyrus adjacent to the amygdala bilaterally, as well as greater WMH volume as a percentage of the total intracranial volume (WMHr). A higher WMHr was associated with cortical thinning in the frontal, temporal, and parietal regions in MCI participants. These results demonstrate that episodic memory and depression are associated with both cortical thickness and WMH volume in MCI participants. Additional longitudinal studies are needed to clarify the dynamic associations and interactions among these indices.
authors.affiliation: Department of Nuclear Medicine, Saitama Medical University International Medical Center Hidaka, Japan ; Integrative Brain Imaging Center, National Center of Neurology and Psychiatry (NCNP), Kodaira Tokyo, Japan.
authors.forename: Motonobu
authors.initials: M
authors.lastname: Fujishima
authors.affiliation: Integrative Brain Imaging Center, National Center of Neurology and Psychiatry (NCNP), Kodaira Tokyo, Japan.
authors.forename: Norihide
authors.initials: N
authors.lastname: Maikusa
authors.affiliation: Division of Geriatric Behavioral Neurology, Cyclotron and Radioisotope Center, Tohoku University Sendai, Japan.
authors.forename: Kei
authors.initials: K
authors.lastname: Nakamura
authors.affiliation: Division of Geriatric Behavioral Neurology, Cyclotron and Radioisotope Center, Tohoku University Sendai, Japan.
authors.forename: Masahiro
authors.initials: M
authors.lastname: Nakatsuka
authors.affiliation: Department of Nuclear Medicine, Saitama Medical University International Medical Center Hidaka, Japan ; Integrative Brain Imaging Center, National Center of Neurology and Psychiatry (NCNP), Kodaira Tokyo, Japan.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Matsuda
authors.affiliation: Division of Geriatric Behavioral Neurology, Cyclotron and Radioisotope Center, Tohoku University Sendai, Japan.
authors.forename: Kenichi
authors.initials: K
authors.lastname: Meguro
keywords: cortical thickness; episodic memory; late-life depression; mild cognitive impairment; white matter hyperintensity