Robust improvements in detail and gist memory through expanding retrieval practice in individuals with amnestic mild...

This study investigated the effects of repeated retrieval practice (RP) on detailed and gist memory retention in individuals with amnestic mild cognitive impairment (aMCI) and cognitively normal (CN) controls, with a focus on the role of hippocampal volume in memory performance. Sixty-seven older adults (30 aMCI, 37 CN) completed neuropsychological assessments and structural magnetic resonance imaging scans. Participants learned two episodic events containing both detailed and gist information; one event was subjected to RP across five retrieval trials. Results showed that although aMCI participants exhibited lower immediate recall than CNs, RP significantly enhanced their retention, ultimately aligning performance with that of CNs. In aMCI, both detailed and gist memory improved markedly between the first and second retrievals, after which performance plateaued, yielding comparable retention gains by the final test. In contrast, CN participants maintained stable performance across trials, indicating limited benefits from RP. Prior to RP, both memory types were positively associated with posterior hippocampal volume. These associations diminished following RP: Detailed memory gains at the third retrieval were instead linked to smaller total hippocampal volumes, whereas gist memory showed no significant relationships. By the final test, hippocampal volume no longer predicted memory performance. These findings suggest that RP may reduce detectable structure-behavior associations, highlighting its potential as a cognitive intervention for mitigating memory decline in at-risk aging populations. (PsycInfo Database Record (c) 2026 APA, all rights reserved).