Relationships Between a New Cultured Cell-Based Serum Anticholinergic Activity Assay and Anticholinergic Burden Scales or Cognitive Performance in Older Adults.

OBJECTIVES: Anticholinergic burden has been associated with deleterious effects on cognition particularly in those with an underlying brain disorder. We developed a new assay based on cultured cells to measure serum anticholinergic activity (cSAA). We report on its relationships with established anticholinergic burden rating scales and cognitive assessments in older patients with mild cognitive impairment (MCI) or major depressive disorder (MDD) in remission or both. DESIGN: The study was cross sectional in nature. SETTING: This was a five-centre study conducted in Toronto, Canada. PARTICIPANTS: Serum samples were collected and cSAA levels were measured in 311 participants aged 60 years or older (154 with MCI, 57 with MDD, and 100 with MCI + MDD). MEASUREMENTS: The cSAA assay uses radio-ligand binding to cultured cells stably expressing the muscarinic M1 receptors, with an added procedure to remove potential confounds associated with serum proteins. Lists of medications were used to calculate Anticholinergic Burden and Anticholinergic Drug Scale total scores. Participants also completed a comprehensive cognitive battery. RESULTS: Higher cSAA levels were associated with higher anticholinergic burden and anticholinergic drug scale scores, and also with lower performance on executive function tests, after adjusting for age, gender, education, and diagnosis. CONCLUSIONS: These results support the use of the cSAA assay as a laboratory measure of anticholinergic burden.

Associations of visual paired associative learning task with global cognition and its potential usefulness as a screening tool for Alzheimer's Dementia.

OBJECTIVE: Appropriate screening is integral to the early diagnosis and management of Alzheimer's Dementia (AD). The Paired Associates Learning (PAL) task is a digital cognitive task that is free of cultural, language, and educational biases. This study examined the association between the PAL task performance and global cognition and the usefulness of the PAL task as a screening tool for AD. DESIGN: Cross-sectional. SETTING: Academic hospital. METHODS: Twenty-five participants with AD and 22 healthy comparators (HC) were included. The Cambridge Neuropsychological Test Automated Battery PAL task and the Montreal Cognitive Assessment (MoCA) were used to assess cognition. We assessed the relationship between the PAL task and MoCA performance using Pearson correlation and linear regression. We also examined the PAL task's ability to distinguish between AD and HC participants using Receiver Operating Characteristic curve (ROC) analysis. MEASUREMENTS: MoCA Total Score had a strong positive correlation with PAL Stages Completed score (r = 0.8, p < 0.001), and a strong negative correlation with PAL Total Errors (adjusted) score (r = -0.9, p < 0.001). Further, PAL Total Errors (adjusted) score predicted the MoCA Total Score (F (4, 46) = 37.2, p < 0.001). On ROC analysis, PAL Total Errors (adjusted) score cut-off of 54 errors had 92% sensitivity and 86% specificity to detect AD. CONCLUSIONS: Performance on the PAL task is highly associated with global cognition. Further, the PAL task can differentiate patients with AD from HCs with high sensitivity and specificity. Thus, the PAL task may hold potential usage as an easy-to-administer screening tool for AD.