Performance on a 1-week delayed recall task is associated with medial temporal lobe structures in neurologically normal older adults

Abstract

Objective Traditional episodic memory tests employ a delayed recall length ranging from 10-30 minutes. The neurobiological process of memory consolidation extends well beyond these time intervals, however, raising the possibility that these tests might not be fully sensitive to the subtle neurocognitive changes found in early disease or age-related decline. We aimed to determine the sensitivity of a 1-week delayed recall paradigm to medial temporal lobe (MTL) structure among neurologically normal older adults. Methods 140 functionally intact, older adults (mean age=75.8) completed a story recall test in which participants learned to 90% criterion. Recall was tested after 30-minutes and 1-week. Participants also completed a standardized list learning task with a 20-minute delay and a structural brain MRI. The medial temporal lobe (MTL), including the parahippocampal gyrus, hippocampus, and entorhinal, was our primary region of interest. Results Controlling for age, education, gender and total intracranial volume, the standard 20- and 30-minute recalls showed no significant relationship with MTL. In contrast, 1-week recall was uniquely associated with MTL structure (partial r=0.24, p=0.006), specifically entorhinal (partial r=0.27; p=0.001) and hippocampal (partial r=0.21, p=0.02) volumes. Conclusion Memory paradigms that utilize 1-week delays are more sensitive than standard paradigms to MTL volumes in neurologically normal older adults. Longer delay periods may improve detection of memory consolidation abilities associated with age-related, and potentially pathological, neurobehavioral change.

Worth the Wait: Delayed Recall after 1 Week Predicts Cognitive and Medial Temporal Lobe Trajectories in Older Adults

“…Other research groups have similarly demonstrated that individuals with subjective cognitive complaints (Manes, Serrano, Calcagno, Cardozo, & Hodges, 2008), pre-symptomatic autosomal dominant AD (Weston et al, 2018), and epilepsy (Butler et al, 2007) show poor performances on extended (1-6 weeks) delayed recall paradigms despite normal performance on memory tests with briefer delays. Neuroanatomically, we also found that worse 1-week delayed recall was cross-sectionally associated with smaller MTL volumes in clinically normal older adults, whereas standard delay periods (20-30 min) were not (Saloner et al, 2018).…”

Associations Between Cerebral Morphology and Objective Memory Performance in Patients With Subjective Cognitive Decline

“…The essential role of medial temporal structures for the consolidation of new information has been known for a long time [50]. The results were consistent with a number of previous studies that have demonstrated relationships between the MTL sub-regions in hippocampus, parahippocampal and delayed recall [47,[51][52][53]. But except for that, we have found the cortical thickness in right superior temporal was correlated with short and long delay recalls.…”

Effects of oral contraceptives and natural menstrual cycling on environmental learning

“…However, examining our data does not support this interpretation since there is enough variability to exclude a ceiling effect. Second, as demonstrated by Saloner et al [ 56 ], the delayed recall length for episodic memory may be important for highlighting differences in performance. Indeed, the delayed recall length usually used in experimental settings ranges from 5 to 30 min, but Saloner et al [ 56 ] demonstrated that experiments that use longer delays (e.g., 1-week) are more sensitive to detecting differences.…”

“…Second, as demonstrated by Saloner et al [ 56 ], the delayed recall length for episodic memory may be important for highlighting differences in performance. Indeed, the delayed recall length usually used in experimental settings ranges from 5 to 30 min, but Saloner et al [ 56 ] demonstrated that experiments that use longer delays (e.g., 1-week) are more sensitive to detecting differences. This finding is in agreement with the knowledge that the neurobiological process of memory consolidation extends well beyond the experimental time intervals, raising the possibility that tests using shorter delays (such as the WalCT) might not be fully sensitive to detecting subtle neurocognitive changes produced by OC use.…”