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Diminution of context association memory structure in subjects with subjective cognitive decline.

ABSTRACT: Alzheimer's disease (AD) progresses insidiously from the preclinical stage to dementia. While people with subjective cognitive decline (SCD) have normal cognitive performance, some may be in the preclinical stage of AD. Neurofibrillary tangles appear first in the transentorhinal cortex, followed by the entorhinal cortex in the clinically silent stage of AD. We expected the earliest changes in subjects with SCD to occur in medial temporal subfields other than the hippocampal proper. These selective structural changes would affect specific memory subcomponents. We used the Family Picture subtest of the Wechsler Memory Scale-III, which was modified to separately compute character, activity, and location subscores for episodic memory subcomponents. We recruited 43 subjects with SCD, 44 subjects with amnesic mild cognitive impairment, and 34 normal controls. MRI was used to assess cortical thickness, subcortical gray matter volume, and fractional anisotropy. The results demonstrated that SCD subjects showed significant cortical atrophy in their bilateral parahippocampus and perirhinal and the left entorhinal cortices but not in their hippocampal regions. SCD subjects also exhibited significantly decreased mean fractional anisotropy in their bilateral uncinate fasciculi. The diminution of cortical thickness over the mesial temporal subfields corresponded to brain areas with early tangle deposition, and early degradation of the uncinate fasciculus was in accordance with the retrogenesis hypothesis. The parahippocampus and perirhinal cortex contribute mainly to context association memory while the entorhinal cortex, along with the uncinate fasciculus, contributes to content-related contextual memory. We proposed that context association and related memory structures are vulnerable in the SCD stage.

SUBMITTER: Fan LY

PROVIDER: S-EPMC6866359 | biostudies-literature | 2018 Jun

REPOSITORIES: biostudies-literature

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Diminution of context association memory structure in subjects with subjective cognitive decline.

Fan Ling-Yun LY Lai Ya-Mei YM Chen Ta-Fu TF Hsu Yung-Chin YC Chen Pin-Yu PY Huang Kuo-Zhou KZ Cheng Ting-Wen TW Tseng Wen-Yi Isaac WI Hua Mau-Sun MS Chen Ya-Fang YF Chiu Ming-Jang MJ

Human brain mapping 20180308 6

Alzheimer's disease (AD) progresses insidiously from the preclinical stage to dementia. While people with subjective cognitive decline (SCD) have normal cognitive performance, some may be in the preclinical stage of AD. Neurofibrillary tangles appear first in the transentorhinal cortex, followed by the entorhinal cortex in the clinically silent stage of AD. We expected the earliest changes in subjects with SCD to occur in medial temporal subfields other than the hippocampal proper. These selecti ...[more]

PMID: 29516634

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Project description:ImportanceSubjective memory complaints (SMCs) are associated with a faster cognitive decline; whether this association is also associated with structural brain alterations, such as white matter hyperintensity (WMH) volumes, requires investigation.ObjectiveTo evaluate the association of SMCs with WMH volumes and cognitive decline and investigate the role of WMH volumes in the association between SMCs and cognitive decline.Design, setting, and participantsThe Chicago Health and Aging Project, a population-based cohort study, enrolled adults aged 65 years or older. Data collection occurred in 3-year cycles from 1993 until 2012. Our study comprised 975 participants with magnetic resonance imaging assessments, of which 900 participants had data on SMCs and covariates, and 713 participants provided 2 or more cognitive assessments during the follow-up. Statistical analyses were conducted from May to October 2021.ExposuresSMCs were obtained from self-reported questionnaire data during clinical evaluations, and the cycle, when reported, constituted the baseline of our study. Based on the frequency and severity of concerns, we categorized participants into 3 groups, (1) no concerns, (2) moderate concerns, and (3) very worried.Main outcomes and measuresVolumetric magnetic resonance imaging measures of WMH volume and neuropsychological testing assessments of global cognition. Linear regression analysis was used to investigate the association between SMCs and WMH volumes in a multivariable model adjusted for age, sex, race and ethnicity, education, APOE4 status, and total intracranial volume. The association of SMCs with cognitive decline was investigated using linear mixed-effects models for age, sex, race and ethnicity, education, APOE4 status, follow-up time, and each variable in interaction with time to estimate the annual longitudinal change in cognitive function.ResultsOf the 900 participants with data on SMCs, covariates, and WMH volumes, 553 (61.4%) were women, 539 (59.9%) were African American, and the mean (SD) age was 79.5 (6.2) years. SMCs were associated with a larger WMH volume and faster cognitive decline. Compared with participants with no concerns, participants who were very worried had higher WMH volumes (β = 0.833; 95% CI, 0.203-1.463) and 174% faster cognitive decline (β = -0.049; 95% CI, -0.076 to -0.022). The association between SMCs and cognitive decline remained statistically significant among individuals with large WMH volumes (ie, within the fourth quartile). Within the fourth quartile of WMH volumes, participants who were very worried had 428% faster cognitive decline (β = -0.077; 95% CI, -0.144 to -0.011) compared with participants with no concerns.Conclusions and relevanceThis cohort study suggests that SMCs, frequently reported by older individuals, are an important sign of cognitive impairment, especially among people with abnormalities in brain structure, such as larger WMH volumes.

Dataset Information

Diminution of context association memory structure in subjects with subjective cognitive decline.

Publications

Diminution of context association memory structure in subjects with subjective cognitive decline.

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