Open AccessLearning deficit in cognitively normal APOE ε4 carriers with LOW β‐amyloid
Author(s) -
Lim Yen Ying,
Baker Jenalle E.,
Mills Andrea,
Bruns Loren,
Fowler Christopher,
Fripp Jurgen,
RaineySmith Stephanie R.,
Ames David,
Masters Colin L,
Maruff Paul
Publication year - 2021
Publication title -
alzheimer's and dementia: diagnosis, assessment and disease monitoring
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.497
H-Index - 37
ISSN - 2352-8729
DOI - 10.1002/dad2.12136
Subject(s) - apolipoprotein e , episodic memory , cognition , audiology , alzheimer's disease , medicine , psychology , disease , neuroscience
In cognitively normal (CN) adults, increased rates of amyloid beta (Aβ) accumulation can be detected in low Aβ (Aβ–) apolipoprotein E ( APOE ) ε4 carriers. We aimed to determine the effect of ε4 on the ability to benefit from experience (ie, learn) in Aβ– CNs. Methods Aβ– CNs (n = 333) underwent episodic memory assessments every 18 months for 108 months. A subset (n = 48) completed the Online Repeatable Cognitive Assessment‐Language Learning Test (ORCA‐LLT) over 6 days. Results Aβ– ε4 carriers showed significantly lower rates of improvement on episodic memory over 108 months compared to non‐carriers (d = 0.3). Rates of learning on the ORCA‐LLT were significantly slower in Aβ– ε4 carriers compared to non‐carriers (d = 1.2). Discussion In Aβ– CNs, ε4 is associated with a reduced ability to benefit from experience. This manifested as reduced practice effects (small to moderate in magnitude) over 108 months on the episodic memory composite, and a learning deficit (large in magnitude) over 6 days on the ORCA‐LLT. Alzheimer's disease (AD)–related cognitive abnormalities can manifest before preclinical AD thresholds.