Value of ophthalmological psychophysical test and MEG in subjects at high risk for sporadic Alzheimer's disease

Abstract

Purpose: The aim of this work was to analyse in subjects at high risk of developing Alzheimer's disease (AD) the possible correlation between psychophysical tests and magnetoencephalography (MEG) in comparison with control subjects. Methods: Extensive ophthalmological analysis, MEG recording, genotyping and magnetic resonance imaging (MRI) were performed on 149 healthy subjects, of whom 109 had a family history of the disease and 40 did not. This sample was subdivided into subgroups aged 40–60 years with an increased risk of AD based on the presence of the ApoEɛ4 allele (ApoEɛ4+) and family history (FH+). 28 participants as higher risk group (ApoEɛ4+ and FH+) and 16 participants as lower risk group (FH‐ and ApoEɛ4‐). Results: In the ApoEɛ4+ and FH+ group, a significant increase in visual acuity was observed, as well as an increase in some spatial frequencies of contrast sensitivity. In addition, in this group, some areas of the inner plexiform layer and the inner nuclear layer were thinned. Between the risk groups, when directly comparing M100 latency or temporal frequency activity associated with the visual response, no significant differences were found. However, there was an association between higher visual acuity and earlier M100 latency and increased activity in the high‐risk groups. Conclusions: There seems to exist an early hyperactivation of the visual system, which would act as a compensatory mechanism, or be a manifestation of a biological malfunction that ultimately leads to toxicity. This hyperactivation represents the first evidence of the consequences of early retinal damage, associated with genetic risk, on visual processing. These changes observed by readily available and non‐invasive techniques could constitute a set of biomarkers for early detection of the disease and assessment of the efficacy of possible future treatments.

Editorial: Early indicators of cognitive decline, Alzheimer's disease, and related dementias captured by neurophysiological tools

“…In response to the imperative requirement for early detection and intervention, the editors of this Research Topic aimed to enhance comprehension of brain integrity, concentrating mainly on biomarker investigations targeting timely identification of the mild cognitive impairment (MCI) stage. As an accelerated cue, traditional diagnostic trajectories for dementia are often initiated with standardized cognitive assessments like the Mini-Mental State Examination and Montreal Cognitive Assessment (Wolf and Ueda, 2021 ; López-Cuenca et al, 2022 ; Whelan et al, 2022 ); yet their limited sensitivity to subtle cognitive impairments has become increasingly pronounced. Furthermore, the influence of pandemic-related lockdowns and lockdown-like measures during conflicts on dementia diagnosis rates cannot be overlooked (Bick and Nelson, 2016 ; Brown et al, 2020 ; Tani et al, 2020 ; Ismail et al, 2021 ; Corney et al, 2022 ; Górski et al, 2022 ).…”