Older adults with subjective memory complaints and brain amyloidosis show stable electroencephalographic rhythms, cortical structure, and cognitive performances over 2 years

TL;DR

The study found that older adults with memory complaints and brain amyloidosis showed stable brain rhythms and cognitive performance over two years, regardless of education level.

Contribution

The study explores how education level affects brain rhythms and progression in older adults with memory complaints and amyloidosis.

Findings

SMCneg with high education showed greater posterior alpha rhythms compared to those with low education.

SMCpos with high education showed reduced alpha rhythms and parietal cortical thickness compared to low education SMCpos.

No significant changes in EEG or MRI markers occurred over two years in the studied group.

Abstract

It is well‐known that in patients with Alzheimer's disease (AD) and high education attainment, cognitive performance is typically better than expected based on the burden of brain neuropathology and neurodegeneration (Stern et al., 2018; doi: 10.1016/j.neuroimage.2018.05.033). This resilience of the cognitive status was attributed to a sort of
cognitive reserve
(CR) accumulated by persons with high education attainment, which predicts a life with engaging job, intellectual, and social demands (Arenaza‐Urquijo et al. 2015; doi: 10.3389/fnagi.2015.00134; Stern et al. 2018). Previous resting‐state eyes‐closed electroencephalographic (rsEEG) studies showed that alpha rhythms in posterior visual and visuospatial areas are related to CR in healthy adults, subjective memory complaints (SMC) seniors, and patients with mild cognitive impairment due to AD (ADMCI).

In the present exploratory study, we used the database of the INSIGHT cohort (Dubois et al., 2018; doi: 10.1016/S1474‐4422(18)30029‐2), we investigated whether older adults with subjective memory complaints (SMC) and brain amyloid‐β accumulation may exhibit clinical progression over 2 years as a function of educational attainment (a proxy of cognitive reserve).

SMCneg with high educational attainment (Edu+) participants showed greater posterior rsEEG alpha rhythms compared to SMCneg with low educational attainment (Edu‐) participants. In contrast, SMCpos Edu+ participants exhibited reduced posterior rsEEG alpha rhythms and parietal cortical thickness compared to SMCpos Edu‐ participants. No EEG (Figure 1) or MRI (Figure 2) marker significantly changed over the 2‐year follow‐up period

These findings suggest that a substantially longer time interval than 2 years should be assessed to evaluate the Alzheimer's disease progression and biomarker‐guided targeted therapies in presymptomatic SMCpos adults.

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