Abstract
Background: Cognitive interventions for neurodegenerative diseases, such as
Alzheimer’s disease (AD), are best targeted at the preclinical stages, and subjective
memory decline (SMD) without objective memory impairment on standard tests in older adults
may represent a very early preclinical stage. Elaborated encoding effectively enhances
memory performance for healthy older adults (HOAs), but has not been examined in people
with SMD.
Objective: To examine elaborated encoding in people with SMD, compared with
HOAs.
Methods: Participants were 32 HOAs and 22 people with SMD, defined using the
Memory Complaint Questionnaire. Participants completed a verbal paired associate learning
(PAL) task with delayed recall under elaborated and non-elaborated encoding conditions, as
well as the California Verbal Learning Test–II.
Results: On the PAL learning trials, with age controlled, a significant
interaction of group X encoding condition emerged, F(1, 51) = 6.47,
MSE = 6.54, p = 0.014, η
p
2
= 0.11. Simple main effects
revealed no differences between groups in the non-elaborated condition, but in the
elaborated condition HOAs recalled more pairs than SMD, although both groups benefited
from elaboration. At delayed recall, HOA recalled more pairs than SMD,
F(1, 51) = 4.59, p = 0.037, η
p
2
= 0.08, and both groups
benefited from elaboration, F(1, 52) = 19.25, p <
0.001, η
p
2
= 0.27.
Conclusion: People with SMD benefit from elaborated encoding, although not to
the same extent as HOAs. This objective difference in complex learning and memory suggests
neural changes in SMD that may represent preclinical AD. Elaborated encoding is a
promising technique to help maintain memory and decrease anxiety in this at-risk
population.
