Everyday cognition scales are related to cognitive function in the early stage of probable Alzheimer's disease and FDG-PET findings

We applied the Everyday Cognition (ECog) scale in normal aging adults and patients with Alzheimer's disease (AD) to investigate associations between neuropsychological tests and neuroimaging markers. A total of 160 normal aging adults and 40 patients with the early stage of probable AD were included. Neuropsychological performance was assessed using the Consortium to Establish a Registry for Alzheimer's Disease Neuropsychological Assessment Battery (CERAD-NAB). 18F-fluorodeoxyglucose positron emission tomography (FDG-PET) scans were used to measure AD-related hypometabolism. Nonparametric Spearman correlation analysis was used to study associations between ECog and z-transformed total CERAD-NAB scores in both groups. The results revealed a significant correlation between total ECog and CERAD-NAB scores (rho = -0.28, p < 0.01), and category verbal fluency test with the executive domain of the ECog scale (rho = -0.20, p < 0.01). The CERAD-NAB scores were also significantly correlated with AD-related hypometabolism (rho = -0.49, p < 0.01). The memory domain of the ECog scale was significantly correlated with FDG uptake in the angular gyrus and posterior cingulum gyrus (rho = -0.41 and -0.46, P < 0.01). In conclusion, both total and memory domain ECog scores were correlated with the neuropsychological tests and neuroimaging biomarkers.