Disease-modifying treatments for Alzheimer's disease (AD) may require implementation during early stages of β-amyloid accumulation, well before patients have objective cognitive decline. In this study we aimed to assess the clinical value of subjective cognitive impairment (SCI) by examining the cross-sectional relationship between β-amyloid load and SCI. Cerebral β-amyloid and SCI was assessed in a cohort of 112 cognitively normal subjects. Subjective cognition was evaluated using specific questions on memory and cognition and the MAC-Q. Participants had cerebral β-amyloid load measured with 18F-Florbetaben Positron Emission Tomography (PET). No associations were found between measures of subjective memory impairment and cerebral β-amyloid. However, by self-reported confusion was predictive of a higher global β-amyloid burden (p = 0.002), after controlling for confounders. Regional analysis revealed significant associations of confusion with β-amyloid in the prefrontal region (p = 0.004), posterior cingulate and precuneus cortices (p = 0.004) and the lateral temporal lobes (p = 0.001) after controlling for confounders. An in vivo biomarker for AD pathology was associated with SCI by self-reported confusion on cross-sectional analysis. Whilst there has been a large body of research on SMC, our results indicate more research is needed to explore symptoms of confusion.
Keywords: Alzheimer’s disease; Confusion; PET imaging; Subjective cognitive impairment; Subjective memory; β-amyloid.