Aging, Neuropsychology, and Cognition最新文献

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.

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.

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.

Relative to younger adults, older adults have a preference and memory advantage for appeals framed to focus on emotion goals (e.g., loving or caring) or positive outcomes (e.g., benefits of health behaviors). Here we examined whether combining goal (emotion vs. future) and valence framing (positive vs. negative) could optimize older adults' appraisal and memory for health appeals. Sixty younger (ages 18-29) and 60 older (ages 64-87) adults viewed, rated and recalled one of the four versions of a health pamphlet, each with a unique combination of goal and valence framing. The results showed a memory advantage for pamphlets focusing on emotion over future goals in both age groups. Older adults also showed a more favorable appraisal and a weak memory advantage for the positively- and emotion-framed pamphlet, relative to younger adults. Thus combining goal and valence framing could optimize the effectiveness of older adults' health appeal communication..

In Alzheimer's dementia (AD), greater declines in semantic fluency (SF) relative to letter fluency (LF) have been assumed to reflect semantic disintegration. However, the same pattern is observed in typical aging and neurodegenerative disorders besides AD. We examined this assumption by comparing different aspects of SF and LF performance in older adults with and without dementia, and identifying which verbal fluency measures most clearly distinguish AD from typical aging. Verbal fluency data were compared from 109 individuals with AD and 66 typically aging adults. Correct items, clusters, and errors were analyzed using both raw counts and proportions. Regression analyses examined Task-by-Group interactions and the impact of demographic variables on verbal fluency measures. ROC analyses examined the sensitivity and specificity of the different outcome measures. In regressions, interactions were found for raw but not proportional data, indicating that different group patterns were driven largely by the number of correct items produced. Similarly, in ROC analyses, raw SF totals showed stronger discriminability between groups than either raw discrepancy scores (SF-LF) or discrepancy ratios (SF/LF). Age and cognitive status (MMSE) were the strongest individual predictors of performance. Findings suggest that AD entails quantitative declines in verbal fluency, but qualitatively similar patterns of performance relative to typically aging adults. Thus, SF declines in AD seem to be at least partially attributable to an exaggeration of the underlying mechanisms common to typical aging, and do not necessarily implicate semantic disintegration.

Recently, two new recognition subtests for the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS) were developed and initially validated in a cohort of older adults who were cognitively intact or classified as amnestic Mild Cognitive Impairment (MCI) or mild Alzheimer's disease (AD). The current paper extends that validation by comparing the recall and recognition subtests of the RBANS, including the existing and recently developed scores, to three commonly used biomarkers in AD in an expanded sample from the initial validation. One hundred fifty-four older adults (65 intact, 46 MCI, 43 AD) were administered the RBANS, which included the recently developed subtests for Story Recognition and Figure Recognition (hits, false positives, total correct), as part of a study on memory and biomarkers. Participants also completed magnetic resonance imaging to obtain hippocampal volumes, positron emission tomography to obtain amyloid plaque deposition, and a blood draw to obtain APOE ε4 status. Whereas correlations between recall scores and biomarkers tended to be moderate (average r = ±0.48), these correlations were comparable across the three recognition total scores (average r = ±0.42), but tended to be lower for recognition hits (average r = ±0.28) and false positives (average r = ±0.38). These results further validate the existing and recently developed recognition scores on the RBANS as providing useful information about brain and genetic pathology in older adults with intact and impaired cognitive functioning.

It is not yet known which specific qualities of cognitively stimulating activities are most likely to enhance cognitive reserve in older adults. Taking an inductive approach to this problem, we asked 504 older adults with subjective and/or cognitive impairment to complete the Cognitively Stimulating Activities Questionnaire (CSA-Q). Exploratory factor analysis identified a 4-factor structure within a split-half sample, after which confirmatory factor analysis cross-validated the model. Retaining 12 CSA-Q items, the 4 factors were dubbed CSA-Processing, CSA-Challenging, CSA-Connecting and CSA-Socializing. Resulting factor weights were analyzed relative to cognitive reserve proxies and neuropsychological domains. All factors except CSA-Challenging were positively linked to cognitive reserve. Neuropsychologically, CSA-Challenging was modestly and positively correlated with processing speed and executive function, while CSA-Processing was positively correlated with executive function. CSA-Socializing had a small positive correlation with processing speed. Our findings offer new insights into late-life stimulating activities, laying the groundwork for longitudinal and intervention studies.