Amyloid positivity impacts trial-specific visual object discrimination performance in cognitively normal older adults

Abigail Raffalski and Leslie Gaynor

Authors:  Raffalski, A.E., Tillotson, S., Gaynor, L.S., Turner, S.M., Curiel, R., Rosselli, M., Duara, R., Loewenstein, D.A., & Bauer, R.M

Faculty Mentor:  Russell Bauer

College:  College of Public Health and Health Professions


Visual object discrimination deficits have been identified in cognitive aging and Alzheimer’s disease (AD) studies, and are shown to be associated with family history of dementia and medial temporal lobe resections. Object discrimination tasks consist of semantic (animal) and non-semantic (non-real object) trial types, for which performance does not typically differ. The present study aims to determine if AD-specific risk, including amyloid positivity and family history of dementia, is more strongly associated with performance on either trial type. Fifty-seven cognitively normal older adults from the 1Florida Alzheimer’s Disease Research Center completed an Object Recognition and Discrimination Task, amyloid PET scans, and clinical interviews. There was a significant trial type (semantic v. non-semantic) x amyloid status (positive v. negative) interaction, (F[1,37] =9.50, p=0.004), such that there was a greater disparity between semantic (68.7, 29) v. non-semantic (90, 13.1) trial performance for amyloid positive cognitively normal older adults v. amyloid negative older adults (83.4, 10.2 vs. 88.7, 10.2). In contrast, trial type x family history of dementia was not significant (F[1,39]=1.56, p=0.22). These findings suggest that amyloid positivity may confer particular risk for reduction in both semantic processing and object discrimination, two cognitive capacities associated with temporal lobe functional processors.

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3 Responses
  1. Abigail Raffalski

    Hi UF students, faculty, and staff! I hope you enjoy my presentation. Please feel free to leave any questions and/or comments below.

  2. Lori Altmann

    Nice job, Abigail.
    Did your group look at the location of the amyloid deposits? Do you think that might influence performance on your task?
    Dr. Altmann