Understanding unfamiliar words in young, young-old, and old-old adults: Inferential processing and the abstraction-deficit hypothesis

Physical activity moderates the association between white matter hyperintensity burden and cognitive change

Objective

Greater physical activity (PA) could delay cognitive decline, yet the underlying mechanisms remain unclear. White matter hyperintensity (WMH) burden is one of the key brain pathologies that have been shown to predict faster cognitive decline at a late age. One possible pathway is that PA may help maintain cognition by mitigating the detrimental effects of brain pathologies, like WMH, on cognitive change. This study aims to examine whether PA moderates the association between WMH burden and cognitive change.

Materials and methods

This population-based longitudinal study included 198 dementia-free adults aged 20-80 years. Leisure-time physical activity (LTPA) was assessed by a self-reported questionnaire. Occupational physical activity (OPA) was a factor score measuring the physical demands of each job. Total physical activity (TPA) was operationalized as the average of z-scores of LTPA and OPA. Outcome variables included 5-year changes in global cognition and in four reference abilities (fluid reasoning, processing speed, memory, and vocabulary). Multivariable linear regression models were used to estimate the moderation effect of PA on the association between white matter hyperintensities and cognitive change, adjusting for age, sex, education, and baseline cognition.

Results

Over approximately 5 years, global cognition (p < 0.001), reasoning (p < 0.001), speed (p < 0.001), and memory (p < 0.05) scores declined, and vocabulary (p < 0.001) increased. Higher WMH burden was correlated with more decline in global cognition (Spearman's rho = -0.229, p = 0.001), reasoning (rho = -0.402, p < 0.001), and speed (rho = -0.319, p < 0.001), and less increase in vocabulary (rho = -0.316, p < 0.001). Greater TPA attenuated the association between WMH burden and changes in reasoning (βTPA^*WMH = 0.029, 95% CI = 0.006-0.052, p = 0.013), speed (βTPA^*WMH = 0.035, 95% CI = -0.004-0.065, p = 0.028), and vocabulary (βTPA^*WMH = 0.034, 95% CI = 0.004-0.065, p = 0.029). OPA seemed to be the factor that exerted a stronger moderation on the relationship between WMH burden and cognitive change.

Conclusion

Physical activity may help maintain reasoning, speed, and vocabulary abilities in face of WMH burden. The cognitive reserve potential of PA warrants further examination.

Electrophysiological correlates of the Categorization Working Memory Span task in older adults

Older adults typically show poor performance in tasks assessing working memory (WM), a crucial cognitive mechanism. The present study examined the electrophysiological correlates of a classic complex WM task often used in studies involving older adults, the Categorization Working Memory Span task (CWMS), by means of event-related potentials. Thirty-five healthy, right-handed older adults (64-75 years) were presented the CWMS task while a 38-channel EEG was measured, and the N1, P1, and word recognition potential (RP) were analyzed on four regions of interest (ROIs) of 5 electrodes each. Additionally, late positive components (P200 and P300) were analyzed in midline ROIs of 3 electrodes each. Participants also executed an n-back task (2-back condition) and an objective performance-based task (the Ability to solve Problems in Everyday life [APE]). At a behavioral level, significant correlations were found between the CWMS, the 2-back, and the APE tests. At a physiological level, N1 and word RP showed greater bilateral amplitude in posterior electrodes, but the better the CWMS and the 2-back performance, the greater the RP amplitude on posterior left sites. The CWMS task induced a clear P200 component, but its amplitude was not correlated with participants' behavioral performance. Altogether, notwithstanding that the bilateral RP pattern elicited by the CWMS is a clear marker of WM processing in older adults, better elderly performers on this complex WM test showed greater left hemisphere dominance to the automatic word RP.

Why Is Working Memory Performance Unstable? A Review of 21 Factors

In this paper, we systematically reviewed twenty-one factors that have been shown to either vary with or influence performance on working memory (WM) tasks. Specifically, we review previous work on the influence of intelligence, gender, age, personality, mental illnesses/medical conditions, dieting, craving, stress/anxiety, emotion/motivation, stereotype threat, temperature, mindfulness training, practice, bilingualism, musical training, altitude/hypoxia, sleep, exercise, diet, psychoactive substances, and brain stimulation on WM performance. In addition to a review of the literature, we suggest several frameworks for classifying these factors, identify shared mechanisms between several variables, and suggest areas requiring further investigation. This review critically examines the breadth of research investigating WM while synthesizing the results across related subfields in psychology.

Aging and individual differences in binding during sentence understanding: evidence from temporary and global syntactic attachment ambiguities

We report an investigation of aging and individual differences in binding information during sentence understanding. An age-continuous sample of adults (N=91), ranging from 18 to 81 years of age, read sentences in which a relative clause could be attached high to a head noun NP1, attached low to its modifying prepositional phrase NP2 (e.g., The son of the princess who scratched himself/herself in public was humiliated), or in which the attachment site of the relative clause was ultimately indeterminate (e.g., The maid of the princess who scratched herself in public was humiliated). Word-by-word reading times and comprehension (e.g., who scratched?) were measured. A series of mixed-effects models were fit to the data, revealing: (1) that, on average, NP1-attached sentences were harder to process and comprehend than NP2-attached sentences; (2) that these average effects were independently moderated by verbal working memory capacity and reading experience, with effects that were most pronounced in the oldest participants and; (3) that readers on average did not allocate extra time to resolve global ambiguities, though older adults with higher working memory span did. Findings are discussed in relation to current models of lifespan cognitive development, working memory, language experience, and the role of prosodic segmentation strategies in reading. Collectively, these data suggest that aging brings differences in sentence understanding, and these differences may depend on independent influences of verbal working memory capacity and reading experience.

Susceptibility to distraction during reading in young, young-old, and old-old adults

BACKGROUND/STUDY CONTEXT: Susceptibility to distraction during reading may increase with age, resulting in comprehension errors. Neurological integrity and cognitive reserve are possible covariates of age-related distraction susceptibility. The current study investigated distraction susceptibility in three age groups (young, young-old, and old-old), and examined the covariation patterns of variable sets associated with neurological integrity and cognitive reserve.

METHODS

Participants responded to comprehension questions after reading stories that included semantically related or semantically unrelated distractors. Neurological integrity measures consisted of Mini-Mental State Examination, Selective Reminding, and Category Fluency. Cognitive reserve measures consisted of education and vocabulary.

RESULTS

Old-old adults were more likely than young and young-old adults to select distractors when responding to comprehension questions (24.02%, 11.95%, 3.68%, respectively). Age-related distraction variance significantly overlapped neurological variance, and became more transparent after cognitive reserve variance was controlled.

CONCLUSION

This study augments previous age-related distraction research by highlighting (a) the increase in distraction susceptibility in adults over 79, particularly when distractors are semantically related; (b) the influence of age-related neurological integrity on distraction; and (c) the possibility that education and verbal experience may decrease distraction susceptibility, consistent with cognitive reserve frameworks.

An inconvenienced youth? Ageism and its potential intergenerational roots

Age is the only social category identifying subgroups that everyone may eventually join. Despite this and despite the well-known growth of the older population, age-based prejudice remains an understudied topic in social psychology. This article systematically reviews the literature on ageism, highlighting extant research on its consequences and theoretical perspectives on its causes. We then identify a crucial gap in the literature, potential intergenerational tensions, speculating how a growing-older population-and society's efforts to accommodate it-might stoke intergenerational fires, particularly among the younger generation. Presenting both sides of this incipient issue, we review relevant empirical work that introduces reasons for both optimism and pessimism concerning intergenerational relations within an aging society. We conclude by suggesting future avenues for ageism research, emphasizing the importance of understanding forthcoming intergenerational dynamics for the benefit of the field and broader society.

Cognitive impairment in old people living in the community

Cognitive impairment has a high prevalence in the elderly, especially in the oldest old, and it is a major concern for autonomous old people living in the community and their families. Any possible intervention will benefit from early detection of cognitive decline related signs. The Portuguese version of the mini-mental state examination (MMSE) was used to assess cognitive impairment in a sample of 1266 old community-dwellers in Portugal, mean age 70.3+/-8.7 years. A standard questionnaire was also used including measures on social network, psychological distress, functionality, perceived health status, and socio-demographic variables. We recorded education levels and illiteracy by using different cut points to select people with and without cognitive impairment and results showed a 9.6% prevalence of positive cases. In general, cognitive impairment is higher in women, older people, widows(ers), and people with negative self-perception of health and with difficulties in basic and in instrumental activities of daily living (ADL and IADL). Cognitive impairment was found to be predicted by gender, age and psychological distress, explaining 18% of variance. Findings are discussed considering available literature and possible interventions for community residents.

Text comprehension products and processes in young, young-old, and old-old adults

Aging may be associated with an increase in generalized text processing, particularly in adults older than 75 years. The current study examined text comprehension in young, young-old, and old-old adults. Experiment 1 included a comprehension measure (product) and Experiment 2 examined inferences generated during reading (process). Comprehension scores were lowest in old-old adults. Generalized and elaborative inference scores were highest in old-old adults. Participants over 65 years with the lowest scores on cognitive integrity variables also had significantly lower comprehension scores, but there was no effect of cognitive integrity on inference scores. This dissociation suggests that inferential processes may be maintained even when cognitive integrity and comprehension declines are present. Relevance to cognitive aging theories addressing text processing and self-regulatory processes is addressed.

Self-regulated reading in adulthood

Young and older adults read a series of passages of 3 different genres for an immediate assessment of text memory (measured by recall and true/false questions). Word-by-word reading times were measured and decomposed into components reflecting resource allocation to particular linguistic processes using regression. Allocation to word and textbase processes showed some consistency across the 3 text types and was predictive of memory performance. Older adults allocated more time to word and textbase processes than the young adults did but showed enhanced contextual facilitation. Structural equation modeling showed that greater resource allocation to word processes was required among readers with relatively low working memory spans and poorer verbal ability and that greater resource allocation to textbase processes was engendered by higher verbal ability. Results are discussed in terms of a model of self-regulated language processing suggesting that older readers may compensate for processing deficiencies through greater reliance on discourse context and on increases in resource allocation that are enabled through growth in crystallized ability.

Vocabulary test format and differential relations to age

Although vocabulary tests are generally considered interchangeable, regardless of format, different tests can have different relations to age and to other cognitive abilities. In this study, 4 vocabulary test formats were examined: multiple-choice synonyms, multiple-choice antonyms, produce the definition, and picture identification. Results indicated that, although they form a single coherent vocabulary knowledge factor, the formats have different relations to age. In earlier adulthood, picture identification had the strongest growth, and produce the definition had the weakest. In later adulthood, picture identification had the strongest decline, and multiple-choice synonyms had the least. The formats differed in their relation to other cognitive variables, including reasoning, spatial visualization, memory, and speed. After accounting for the differential relations to other cognitive variables, differences in relation to age were eliminated with the exception of differences for the picture identification test. No theory of the aging of vocabulary knowledge fully explains these findings. These results suggest that using a single indicator of vocabulary may yield incomplete and somewhat misleading results about the aging of vocabulary knowledge.

Working memory and inhibition across the adult life-span

Research has shown that age-related changes in cognitive performance are due mostly to the decline of general factors such as working memory and inhibition. The present study is aimed at investigating age-related changes in these mechanisms across the adult life-span from 20 to 86 years of age. Results indicate a linear relationship between each working memory measure and age, independently of the nature of the task, and a quadratic relationship between the single inhibitory measures and age. Moreover, hierarchical regression analyses show that inhibition accounts for a significant, but modest, part of the age-related variance in working memory. Taken together, these results suggest that inhibition is not as crucial a contributor of age-related changes in the functional capacity of working memory across the adult life-span as previously thought.

Language and the aging brain: patterns of neural compensation revealed by functional brain imaging

Human aging brings with it declines in sensory function, both in vision and in hearing, as well as a general slowing in a variety of perceptual and cognitive operations. Yet in spite of these declines, language comprehension typically remains well preserved in normal aging. We review data from functional magnetic resonance imaging (fMRI) to describe a two-component model of sentence comprehension: a core sentence-processing area located in the perisylvian region of the left cerebral hemisphere and an associated network of brain regions that support the working memory and other resources needed for comprehension of long or syntactically complex sentences. We use this two-component model to describe the nature of compensatory recruitment of novel brain regions observed when healthy older adults show the same success at comprehending sentences as their younger adult counterparts. We suggest that this plasticity in neural recruitment contributes to the stability of language comprehension in the aging brain.

Aging and self-regulated language processing

An adult developmental model of self-regulated language processing (SRLP) is introduced, in which the allocation policy with which a reader engages text is driven by declines in processing capacity, growth in knowledge-based processes, and age-related shifts in reading goals. Evidence is presented to show that the individual reader's allocation policy is consistent across time and across different types of text, can serve a compensatory function in relation to abilities, and is predictive of subsequent memory performance. As such, it is an important facet of language understanding and learning from text through the adult life span.

A structural factor analysis of vocabulary knowledge and relations to age

Vocabulary knowledge may not be a unidimensional construct, and the relations between vocabulary knowledge and age may depend on the aspect of vocabulary knowledge being assessed. In this study, we examined the factor structure of a vocabulary test given to a large nationally representative sample of individuals (N approximately 20,500). Results indicated that the vocabulary test is not unidimensional but bidimensional, with Basic Vocabulary and Advanced Vocabulary factors. An analysis of age differences indicates that basic vocabulary is highest around the age of 30, with a negative relation to age in late adulthood; in contrast, advanced vocabulary is unrelated to age between ages 35 and 70. Cohort effects may explain some of the differential age trend.