The novel visual cognitive assessment test correlates well with plasma oligomeric amyloid beta in patients with mild cognitive impairment

Abstract

AbstractBackgroundOligomeric Amyloid Beta (OAβ), is representative of a soluble, neurotoxic and pathogenic form of Aβ, which has been found to function as upstream drivers of Alzheimer’s Disease pathology (Tolar et al., 2021). It serves as a contributory factor towards the formation of cortical Aβ plaques and neurofibrillary Tau tangles, and has been found to induce oxidative stress, synaptic toxicity and neuroinflammation (Tolar et al., 2021). The pathology culminates in neuronal dysfunction/death and resultant neurodegeneration which has been found to manifest clinically as symptoms of cognitive decline. OAβ has been found to correlate with the severity of cognitive performance, as well as brain volume reduction (An et al., 2017, Wang et al., 2017, Meng et al., 2019, Youn et al., 2019, Babapour Mofrad et al., 2021). Nevertheless, its effect on language neutral cognitive tests ‐ the novel Visual Cognitive Assessment Test (VCAT) developed and validated by our team of neurologist and neuropsychologists; remains to be evaluated (Kandiah et al., 2016, Lim et al., 2018, Low et al., 2020).MethodsA cross‐sectional pilot study was conducted in a cohort of 63 patients, clinically diagnosed with mild cognitive impairment (MCI). The patients underwent cognitive evaluation tests, Multimer Detection System (MDS) based plasma OAβ analysis and MRI based cortical grey matter evaluations (Wang et al., 2017, Youn et al., 2019, Pyun et al., 2021, Vipin et al., 2021). Pearson’s correlation evaluated associations between plasma OAβ, cognitive scores [Mini‐Mental State Examination (MMSE), VCAT] and brain volume measures [Grey Matter Volume (GMV) / Intracranial Volume (ICV)].ResultsIncreasing plasma OAβ expression associated with decreasing, VCAT scores (r = ‐0.291, 95% CI = ‐0.504 to ‐0.044, p = 0.022) and MMSE scores (r = ‐0.272, 95% CI = ‐0.489 to ‐0.024, p = 0.032), in MCI patients (Figure 1A, B). Additionally increasing plasma OAβ expression also associated with decreasing and GMV/ ICV ratio (r = ‐0.264, 95% CI = ‐0.489 to ‐0.007, p = 0.045), in MCI patients (Figure 1C).ConclusionFindings from this study, emphasise on the promising clinical utility of plasma OAβ as a biomarker. Future longitudinal studies will validate these associations across the Alzheimer’s disease spectrum.