Association of deficits in short-term learning and Aβ and hippocampal volume in cognitively normal adults
Authors
Yen Ying Lim
Jenalle E. Baker
Loren Bruns
Andrea Mills
Christopher Fowler
Jurgen Fripp
Stephanie R. Rainey-Smith, Edith Cowan UniversityFollow
David Ames
Colin L. Masters
Paul Maruff
Document Type
Journal Article
Publication Title
Neurology
Volume
95
Issue
18
First Page
e2577
Last Page
e2585
Publisher
Wolters Kluwer
School
School of Medical and Health Sciences
RAS ID
35342
Abstract
© 2020 American Academy of Neurology. OBJECTIVE: To determine the extent to which deficits in learning over 6 days are associated with β-amyloid-positive (Aβ+) and hippocampal volume in cognitively normal (CN) adults. METHODS: Eighty CN older adults who had undergone PET neuroimaging to determine Aβ status (n = 42 Aβ- and 38 Aβ+), MRI to determine hippocampal and ventricular volume, and repeated assessment of memory were recruited from the Australian Imaging, Biomarkers and Lifestyle (AIBL) study. Participants completed the Online Repeatable Cognitive Assessment-Language Learning Test (ORCA-LLT), which required they learn associations between 50 Chinese characters and their English language equivalents over 6 days. ORCA-LLT assessments were supervised on the first day and were completed remotely online for all remaining days. RESULTS: Learning curves in the Aβ+ CN participants were significantly worse than those in matched Aβ- CN participants, with the magnitude of this difference very large (d [95% confidence interval (CI)] 2.22 [1.64-2.75], p < 0.001), and greater than differences between these groups for memory decline since their enrollment in AIBL (d [95% CI] 0.52 [0.07-0.96], p = 0.021), or memory impairment at their most recent visit. In Aβ+ CN adults, slower rates of learning were associated with smaller hippocampal and larger ventricular volumes. CONCLUSIONS: These results suggest that in CN participants, Aβ+ is associated more strongly with a deficit in learning than any aspect of memory dysfunction. Slower rates of learning in Aβ+ CN participants were associated with hippocampal volume loss. Considered together, these data suggest that the primary cognitive consequence of Aβ+ is a failure to benefit from experience when exposed to novel stimuli, even over very short periods.
DOI
10.1212/WNL.0000000000010728
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Comments
Lim, Y. Y., Baker, J. E., Bruns, L., Mills, A., Fowler, C., Fripp, J., … Maruff, P. (2020). Association of deficits in short-term learning and Aβ and hippocampal volume in cognitively normal adults. Neurology, 95(18), e2577-e2585. https://doi.org/10.1212/WNL.0000000000010728