Aging, Neuropsychology, and Cognition最新文献

While aging has been associated with decreased retrieval of episodic memory details, subjective ratings about memory quality seem to remain stable. This suggests that subjective memory judgments are based on different information according to age. Here, we tested the hypothesis that older people would rather base their subjective judgments on the retrieval of personal elements (such as emotions and thoughts), whereas younger people would rather base their judgments on the retrieval of event-related elements (such as time, place, and perceptual details). Sixty participants (20 to 79 years old) performed eight actions in a virtual apartment and were then asked to verbally recall each action with a maximum of associated elements and to rate the subjective quality of their memories. The elements reported were classified into "person-related" and "event-related" categories. Executive functions, memory performance on traditional memory tasks, and subjects' perception of memory functioning were also evaluated. Results revealed that aging was associated with reduced retrieval of event-related elements, which was explained by decreasing executive resources. However, age did not affect the retrieval of person-related elements, and the subjective memory judgments of older people were not based on these elements to a greater extent than those of younger people. Finally, our results highlight the value of virtual reality (VR) in memory evaluations since subjects' perception of memory functioning was associated with their performance in the VR task but not in traditional memory tasks.

The present study focuses on referential choices made by healthy aged adults during narrative discourse, and their relationship with cognitive and socio-cognitive abilities. Previously, some studies have shown that, compared to young adults, older adults produce more pronouns when referring to various entities during discourse, regardless of the accessibility level of the referent for the addressee. This referential behavior has been interpreted in relation to the decrease of cognitive abilities, such as working memory abilities. There is, as of yet, little empirical evidence highlighting which cognitive competences preferentially support referential choices during discourse production. Here, we focus on three categories of referential markers (indefinite, definite markers and pronouns) produced by 78 participants from 60 to 91 years old. We used a storytelling task enabling us to examine the referential choices made at three discourse stages (introduction, maintaining or shift of the referent in focus) and in increasing levels of referential complexity (one vs two characters, and different vs same gender). In addition to specifically assessing how increasing age influences referential choices, we also examine the contribution of various cognitive and socio-cognitive skills that are presumed to play a specific role in referential choices. We found that both age and specific cognitive abilities (planification, inhibition, and verbal episodic memory) had an effect on referential choices, but that these effects depended on when (at which discourse stage) the referential markers were produced. Overall, our study highlights the complex interplay between discursive and cognitive factors in referential choices made by healthy older speakers.

Associative memory deficits in aging are frequently characterized by false recognition of novel stimulus associations, particularly when stimuli are similar. Introducing distinctive stimuli, therefore, can help guide item differentiation in memory and can further our understanding of how age-related brain changes impact behavior. How older adults use different types of distinctive information to distinguish overlapping events in memory and to avoid false associative recognition is still unknown. To test this, we manipulated the distinctiveness of items from two stimulus categories, scenes and objects, across three conditions: (1) distinct scenes paired with similar objects, (2) similar scenes paired with distinct objects, and (3) similar scenes paired with similar objects. Young and older adults studied scene-object pairs and then made both remember/know judgments toward single items as well as associative memory judgments to old and novel scene-object pairs ("Were these paired together?"). Older adults showed intact single item recognition of scenes and objects, regardless of whether those objects and scenes were similar or distinct. In contrast, relative to younger adults, older adults showed elevated false recognition for scene-object pairs, even when the scenes were distinct. These age-related associative memory deficits, however, disappeared if the pair contained an object that was visually distinct. In line with neural evidence that hippocampal functioning and scene processing decline with age, these results suggest that older adults can rely on memory for distinct objects, but not for distinct scenes, to distinguish between memories with overlapping features.

We examined age-related similarities and differences in people's metacognitive awareness of retrieval from semantic long-term memory as well as the originality of their responses. Participants completed several semantic fluency tasks, and before recalling items, made metacognitive predictions of their performance. Additionally, after retrieval, participants made metacognitive evaluations of the originality of their responses. Results revealed that both younger (M_age = 24.49) and older adults (M_age = 68.31) were underconfident in their performance, despite some metacognitive awareness of their ability to retrieve information from semantic memory. Younger and older adults became more metacognitively aware of their abilities with task experience, but there were no significant differences in participants' metacognitive predictions and postdictions, although older adults believed that they were less original than younger adults. These findings revealed a "skilled and unaware" effect whereby participants were underconfident on the first trial and became less underconfident on later trials. These patterns may fit with a broader literature that has found a lack of adult age differences in metacognition for verbal skills but shows that older adults may believe that their access to original verbal knowledge may decline in older age.

Sensitivity to the fixed ordering of actions and events, or deterministic sequence learning, is an important skill throughout adulthood. Yet, it remains unclear whether age deficits in sequencing exist, and we lack a firm understanding of which factors might contribute to age-related impairments when they arise. Though debated, executive functioning, governed by the frontal lobe, may underlie age-related sequence learning deficits in older adults. The present study asked if age predicts errors in deterministic sequence learning across the older adult lifespan (ages 55-89), and whether executive functioning accounts for any age-related declines. Healthy older adults completed a comprehensive measure of frontal-based executive abilities as well as a deterministic sequence learning task that required the step-by-step acquisition of associations through trial-and-error feedback. Among those who met a performance-based criterion, increasing age was positively correlated with higher sequencing errors; however, this relationship was no longer significant after controlling for executive functioning. Moreover, frontal-based executive abilities mediated the relationship between age and sequence learning performance. These findings suggest that executive or frontal functioning may underlie age deficits in learning judgment-based, deterministic serial operations.

Subjective memory is commonly used as an indicator of older adults' objective memory in clinical screening; however, the correspondence between subjective and objective memory across different ages is unclear. The current study examined age-varying associations between subjective and objective memory in a cross-sectional sample of healthy older adults from the Advanced Cognitive Training for Independent and Vital Elderly (ACTIVE) study (N = 2,496). Time varying effects modeling (TVEM) models the association between variables as a function of time-varying metrics including age without imposing linear assumptions. TVEM was used to examine relationship magnitude fluctuations between subjective and objective memory across ages 65 to 85. Better subjective memory was weakly associated with better objective memory, even after controlling for gender, depressive symptoms, and education. The association was stable across all ages. There is a stable weak correspondence between subjective and objective memory in older adulthood across age, supporting the use of linear age as an appropriate time metric for examinations of objective and subjective memory among healthy older adults. Future work should examine the correspondence between subjective and objective memory in a larger age range. Longitudinal designs can also provide insights on whether the accuracy of subjective memory ratings change within a person over time.

Mild cognitive Impairment (MCI) is notoriously heterogenous in terms of clinical presentation, neuroimaging correlates, and subsequent progression. Predicting who will progress to dementia, which type of dementia, and over what timeframe is challenging. Previous work has attempted to identify MCI subtypes using neuropsychological measures in an effort to address this challenge; however, there is no consensus on approach, which may account for some of the variability. Using a hierarchical community detection approach, we examined cognitive subtypes within an MCI sample (from the Alzheimer's Disease Neuroimaging Initiative [ADNI] study). We then examined whether these subtypes were related to biomarkers (e.g., cortical volumes, fluorodeoxyglucose (FDG)-positron emission tomography (PET) hypometabolism) or clinical progression. We identified five communities (i.e., cognitive subtypes) within the MCI sample: 1) predominantly memory impairment, 2) predominantly language impairment, 3) cognitively normal, 4) multidomain, with notable executive dysfunction, 5) multidomain, with notable processing speed impairment. Community membership was significantly associated with 1) cortical volume in the hippocampus, entorhinal cortex, and fusiform cortex; 2) FDG PET hypometabolism in the posterior cingulate, angular gyrus, and inferior/middle temporal gyrus; and 3) conversion to dementia at follow up. Overall, community detection as an approach appears a viable method for identifying unique cognitive subtypes in a neurodegenerative sample that were linked to several meaningful biomarkers and modestly with progression at one year follow up.

The goal of our research was to investigate whether older adults show a source memory enhancement for emotionally valenced sources. Additionally, building on research on the socioemotional selectivity theory and the age-related positivity effect, we tested whether older adults show a larger enhancement for positive compared to negative (and neutral) sources than younger adults. In Experiment 1 (n_old = 25, n_young = 27), we used one positive, one negative, and one neutral picture to manipulate source valence (many-to-one mapping of items to sources), whereas, in Experiment 2 (n_old = 62, n_young = 62), we used multiple pictures per source valence category (one-to-one mapping of items to sources) to counteract potential habituation effects. In both experiments, sources had medium and matching arousal levels. Items were neutral words superimposed on the source pictures. To support an implicit, natural information processing, participants rated the words in terms of pleasantness. We analyzed memory data with a multinomial processing tree model to disentangle memory processes from guessing bias. Across both experiments, an age-related positivity effect occurred in participants' pleasantness ratings. This effect, however, did not carry over to older adults' source memory. That is, in source memory, we found a general emotionality effect for younger but not for older adults and no age-related positivity effect. We propose that due to older adults' pronounced difficulties in remembering the item-to-source link (i.e., associative deficit), even a greater focus on an inherently emotional source might be insufficient to boost source memory.