Ageing and organisation strategies in free recall: The role of cognitive flexibility

Validity of the Chinese version of the weekly calendar planning activity (WCPA) on assessing executive function in adults with stroke

The weekly calendar planning activity (WCPA) is a performance-based assessment of executive function (EF) via a cognitively-based instrumental activity of daily life (C-IADL). This study aimed to examine the validity of the Chinese version of the WCPA in adults with stroke and to explore the characteristics of cognitive strategy use among the population. Fifty-eight hospitalized patients with stroke aged 26-82 years and 53 controls completed the WCPA, two neuropsychological tests and instrumental activity of daily life (IADL) scale. Participants with stroke were subdivided into a stroke cognitive impaired group (Stroke-CI) and a general stroke group (Stroke-NCI) based on the Montreal Cognitive Assessment. Results showed that the WCPA was able to discriminate between Stroke-CI with controls and the Stroke-NCI group with controls. We found significant limitations in stroke patients' ability to use strategies. Concurrent and ecological validities were demonstrated through correlations between the neuropsychological test scores, IADL and the WCPA performance. This study provides initial evidence for the validity of the Chinese version of the WCPA-10 for adults with stroke and suggests the need to use performance-based tests even in patients with normal cognitive screening test results. The WCPA could provide useful information for strategy-based interventions for adults with stroke.

Protective effects of physical activity on episodic memory during aging are explained by executive functioning

Aging is marked by a memory decline related to an executive function decline. Physical activity (PA) has beneficial effects on both executive functions and memory, especially in aging. The protective effects of PA on these two cognitive abilities have always been studied separately, despite the well-established relationship between memory and executive functions. Our objective was to explore whether the benefits of PA on memory could be explained by reduced age-related changes in executive functions.Nineteen young adults (27.16 years old) and 25 older adults (69.64 years old) performed a resource-dependent memory task, three executive tasks and completed a PA questionnaire (measuring sports and leisure PA). Age group and PA effects on memory and executive performance were analyzed with generalized linear models. Mediation analyses were calculated using method of causal steps approach with a non-parametric bootstrapping procedure.The results confirmed the effects of age and PA on memory and executive performance. A significant interaction confirmed the protective effect of PA on age-related cognitive performance. PA was positively correlated with performance in both memory and executive tasks, but only in the older adults. Although each predictor alone (age, executive functions and PA) significantly explained memory performance in older adults, only the effect of PA on memory performance remained significant when all the predictors were introduced in the analyses.PA mediates the effects of age and executive functions on memory performance. This suggests that PA protects older adults against memory decline by reducing the decline in executive functioning.

Semantic Clustering during Verbal Episodic Memory Encoding and Retrieval in Older Adults: One Cognitive Mechanism of Superaging

Normal aging is commonly accompanied by a decline in cognitive abilities, including memory, yet some individuals maintain these abilities as they get older. We hypothesize that semantic clustering, as an effective strategy for improving performance on episodic recall tasks, may contribute to the maintenance of youthful memory in older adults. We investigated the dynamics of spontaneous production and utilization of the semantic clustering strategy in two independent samples of older adults who completed a list learning paradigm (N1 = 40 and N2 = 29, respectively). Specifically, we predicted and observed that older adults who spontaneously used a semantic clustering strategy throughout the encoding process learned more words by the culmination of the encoding trials (Sample 1, R2= 0.53, p < 0.001; Sample 2, R2= 0.51, p < 0.001), and that those who utilized this strategy during retrieval recalled more words, when compared to older adults who did not produce or utilize a semantic clustering strategy during both a short (Sample 1, R2 = 0.81, p < 0.001; Sample 2, R2 = 0.70, p < 0.001) and long delay retrieval (Sample 1, R2 = 0.83, p < 0.001; Sample 2, R2 = 0.77, p < 0.001). We further predicted and observed that older adults who maintained a youthful level of delayed free recall (i.e., "Superagers") produced (Sample 1, F(1, 38) = 17.81, p < 0.0001; Sample 2, F(1, 27) = 14.45, p < 0.0001) and utilized (Sample 1, F(1, 39) = 25.84, p < 0.0001; Sample 2, F(1, 27) = 12.97, p < 0.01) more semantic clustering than did older individuals with normal memory for their age. These results suggest one cognitive mechanism through which Superagers maintain youthful memory function and raise the possibility that older adults may be able to train themselves to use strategies to promote better memory.

Effects of healthy aging and mnemonic strategies on verbal memory performance across the adult lifespan: Mediating role of posterior hippocampus

In this study, we aimed to understand the contributions of hippocampal anteroposterior subregions (head, body, tail) and subfields (cornu ammonis 1-3 [CA1-3], dentate gyrus [DG], and subiculum [Sub]) and encoding strategies to the age-related verbal memory decline. Healthy participants were administered the California Verbal Learning Test-II to evaluate verbal memory performance and encoding strategies and underwent 4.7 T magnetic resonance imaging brain scan with subsequent hippocampal subregions and subfields manual segmentation. While total hippocampal volume was not associated with verbal memory performance, we found the volumes of the posterior hippocampus (body) and Sub showed significant effects on verbal memory performance. Additionally, the age-related volume decline in hippocampal body volume contributed to lower use of semantic clustering, resulting in lower verbal memory performance. The effect of Sub on verbal memory was statistically independent of encoding strategies. While total CA1-3 and DG volumes did not show direct or indirect effects on verbal memory, exploratory analyses with DG and CA1-3 volumes within the hippocampal body subregion suggested an indirect effect of age-related volumetric reduction on verbal memory performance through semantic clustering. As semantic clustering is sensitive to age-related hippocampal volumetric decline but not to the direct effect of age, further investigation of mechanisms supporting semantic clustering can have implications for early detection of cognitive impairments and decline.

Judgments of learning in bilinguals: Does studying in a L2 hinder learning monitoring?

Nowadays, use of a second language (L2) has taken a central role in daily activities. There are numerous contexts in which people have to process information, acquire new knowledge, or make decisions via a second language. For example, in academia and higher education, English is commonly used as the language of instruction and communication even though English might not be students' native or first language (L1) and they might not be proficient in it. Such students may face different challenges when studying and learning in L2 relative to contexts in which they study and learn in their L1, and this may affect their metamemory strategies. However, little is yet known about whether metamemory processes undergo significant changes when learning is carried out in L2. The aim of the present study was to investigate the possible consequences on learning derived from studying materials in L2 and, more specifically, to explore whether the interplay between monitoring and control (metamemory processes) changes as a function of the language involved. In three experiments, we explored whether font type (Experiment 1), concreteness (Experiment 2), and relatedness (Experiment 3) affected judgments of learning (JOLs) and memory performance in both L1 and L2. JOLs are considered the result of metacognitive strategies involved in the monitoring of learning and have been reported to vary with the difficulty of the material. The results of this study showed that people were able to monitor their learning in both L1 and L2, even though they judged L2 learning as more difficult than L1. Interestingly, self-perceived difficulty did not hinder learning, and people recognized L2 materials as well or better than L1 materials. We suggest that this might be an example of a desirable difficulty for memory.

Word-association norms for 1,100 French words with varying levels of concreteness

The organisation of concepts in the mental lexicon is a widely studied research topic in experimental psychology. For instance, several studies have shown that whereas concrete concepts are organised according to semantic similarity, abstract concepts are organised according to verbal association. However, these results are not systematically replicated, mainly due to a lack of normative database especially in French. To that end, we introduce a French word-association database for 1,100 cues with varying levels of concreteness from abstract to concrete concepts. Analyses from the word-association task revealed stronger association strength for concrete concepts compared with abstract concepts. Additional results showed that cues tend to elicit responses of a similar level of concreteness. The database will be useful for investigators interested in French verbal associations for abstract and concrete concepts. The data (available on OSF https://osf.io/dhuqs/) introduce responses organised according to association strength and provides cue concreteness.

The protective effect of educational level varies as a function of the difficulty of the memory task in ageing

This study aimed to explore the effects of age and educational level on recall performance and organisational strategies used during recall as a function of the level of memory task difficulty. Younger (n = 55, age range = 20-39 years) and older (n = 45, age range = 65-75 years) adults learned a word list where the words were either already semantically grouped (easier) or presented in pseudo-random order (harder), and then recalled the words. The number of words recalled was calculated, and an index of clustering was computed to assess organisational strategies. Older adults recalled less words than the younger ones. Older adults with a higher educational level recalled more words than their counterparts with a lower educational level when the memory task was easier, but they all performed similarly on the harder memory task. Moreover, we noted a strong positive association between educational level and semantic organisation in older adults when the memory task was easier. Regardless of educational level, older adults used semantic organisation as much as younger adults when the memory task was easier. However, when the memory task was harder, older adults showed significantly less organisational strategies than younger adults, the latter using semantic organisation to boost their recall performance. In sum, the protective effect of educational level seems to be restricted on recall performance, but not organisational strategies, in easy memory tasks providing sufficient external information about the most efficient mnemonic strategy to use.

Supplementary Information

The online version contains supplementary material available at 10.1007/s10433-022-00724-z.

Executive tasks and cognitive flexibility and their relationship to academic achievement among university students with attention deficit hyperactivity disorder

BACKGROUND

The current study measured the executive tasks and cognitive flexibility and their relationship to the academic achievement of female students of the College of Education at Imam Abdulrahman Bin Faisal University in the Kingdom of Saudi Arabia.

MATERIALS AND METHODS

This research is a descriptive quantitative design. The study sample included 200 female students using purposive sampling. The study applied a test of executive tasks, cognitive flexibility, and a scale of attention deficit hyperactivity disorder for adults prepared by the researchers. Data were analyzed using several tests, namely descriptive statistics, Pearson correlation at the level of <0.05.

RESULTS

The results showed a statistically significant relationship between the scores of students with attention deficit and hyperactivity on the executive tasks scale and its dimensions (planning, organization, purposeful action, self-monitoring, and total score), cognitive flexibility, and academic achievement, which necessitates the need to design empirical research to reduce the severity of attention deficit hyperactivity disorder among undergraduate students because it will have a positive impact on their academic achievement.

CONCLUSION

The researchers highlight the necessity for conducting empirical research to improve the executive tasks of students as it will have a positive impact on their lives.

Disrupted Value-Directed Strategic Processing in Individuals with Mild Cognitive Impairment: Behavioral and Neural Correlates

Value-directed strategic processing involves attending to higher-value information while inhibiting lower-value information. This preferential processing is relatively preserved in cognitively normal older adults but is impaired in individuals with dementia. No studies have investigated whether value-directed strategic processing is disrupted in earlier stages of cognitive decline, namely, mild cognitive impairment (MCI). The current study examined behavioral and EEG differences in value-directed strategic processing between 18 individuals with MCI and 18 cognitively normal older controls using a value-directed list learning task. Behaviorally, individuals with MCI recalled fewer total and high-value words compared to controls, but no group differences were observed in low-value word recall. Neurally, individuals with MCI had reduced theta synchronization relative to controls between 100 and 200 ms post-stimulus. Greater alpha desynchronization was observed for high- versus low-value words between 300 and 400 ms in controls but not in the MCI group. The groups showed some processing similarities, with greater theta synchronization for low-value words between 700 and 800 ms and greater alpha desynchronization for high-value words between 500 and 1100 ms. Overall, value-directed strategic processing was compromised in individuals with MCI on both behavioral and neural measures relative to controls. These findings add to the growing body of literature on differences between typical cognitive aging and MCI.

Episodic memory and aging: Benefits of physical activity depend on the executive resources required for the task

Physical activity has beneficial effects on executive functions and episodic memory, two processes affected by aging. These benefits seem to depend on the type of memory task, but only a few studies have evaluated them despite their importance in understanding aging. This study aimed to confirm that the benefits of physical activity on episodic memory in older adults vary according to the executive resources required by the memory task, comparing free recall and cued recall. Thirty-seven young adults and 37 older adults performed two memory tasks and an updating task. The two groups had a similar level of physical activity over the preceding 12 months, assessed by a questionnaire. Both the memory and the updating tasks were performed better by the younger than the older adults. A similar cueing effect was observed in the two groups. Physical activity was positively correlated with updating and free recall, but not with cued-recall, and only in older adults. Regression analyses indicated that physical activity accounted for 24% of the variance in free recall in older adults. Updating did not predict free recall (ns) when physical activity was entered in the analysis. The present results show that the benefits of physical activity vary with age and episodic memory task. Only free-recall performance, which relies on updating, seems to depend on physical activity, suggesting that the executive resources required for the task play an important role in the effect of physical activity on memory performance. This should be investigated in greater depth in subsequent studies.

The Role of Executive Functions in Item Recognition and Temporal Order Memory Development

Item recognition and temporal order memory follow different developmental trajectories during middle childhood, with item recognition performance stabilizing and temporal order memory performance continuing to improve. We investigated the potential unique role of individual executive functions on item recognition and temporal order memory during this critical development period. Our results replicate and expand on previous findings, suggesting that executive functions, specifically inhibitory control and working memory, may be more crucial for successful temporal order memory than for item recognition during middle childhood.

EXPRESS: Age-related differences when searching in a real environment: The use of semantic contextual guidance and incidental object encoding

Visual search is a crucial, everyday activity that declines with aging. Here, referring to the environmental support account, we hypothesized that semantic contextual associations between the target and the neighboring objects (e.g., a teacup near a tea bag and a spoon), acting as external cues, may counteract this decline. Moreover, when searching for a target, viewers may encode information about the co-present distractor objects, by simply looking at them. In everyday life, where viewers often search for several targets within the same environment, such distractor objects may often become targets of future searches. Thus, we examined whether incidentally fixating a target during previous trials, when it was a distractor, may also modulate the impact of aging on search performance. We used everyday object arrays on tables in a real room, where healthy young and older adults had to search sequentially for multiple objects across different trials within the same array. We showed that search was quicker: (1) in young than older adults, (2) for targets surrounded by semantically associated objects than unassociated objects, but only in older adults, and (3) for incidentally fixated targets than for targets that were not fixated when they were distractors, with no differences between young and older adults. These results suggest that older viewers use both environmental support based on object semantic associations and object information incidentally encoded to enhance efficiency of real-world search, even in relatively simple environments. This reduces, but does not eliminate, search decline related to aging.

Examining the roles of cognitive flexibility, emotion recognition, and metacognitions in adult Attention Deficit and Hyperactivity Disorder with predominantly inattentive presentation

The evaluation of cognitive functions in Attention Deficit and Hyperactivity Disorder (ADHD) is fundamental to improve the efficacy of therapeutic interventions. However, the role of specific higher-order cognitive functions in adult ADHD, including cognitive flexibility, emotion recognition, and metacognitions, remains unclear. Therefore, in the current study, we aimed to examine these three distinct higher-order cognitive functions among adult ADHD individuals. Forty patients with ADHD with predominantly inattentive presentation and 42 healthy controls participated in the study. The Adult Attention Deficit and Hyperactivity Disorder Scale (AADHDS), the Wisconsin Card Sorting Test (WCST), the Reading the Mind in the Eyes Test (RMET), and the Metacognitions Questionnaire-30 (MCQ-30) were administered. Results indicated that patients with ADHD had worse metacognitions scores, in specific subdimensions, relative to healthy controls. However, cognitive flexibility and emotion recognition did not differ between the groups. Moreover, the cognitive confidence subdimension of the MCQ-30 was found to be sole significant predictor in the attention deficit subdimension of the AADHDS. Our findings suggest that lack of cognitive confidence may contribute to ADHD symptomatology despite regularly functioning cognitive flexibility and emotion recognition. Therefore, metacognitions could be a suitable target to alleviate the severity of ADHD symptoms.

Testing a Novel Web-Based Neurocognitive Battery in the General Community: Validation and Usability Study

BACKGROUND

In recent years, there has been increased interest in the development of remote psychological assessments. These platforms increase accessibility and allow clinicians to monitor important health metrics, thereby informing patient-centered treatment.

OBJECTIVE

In this study, we report the properties and usability of a new web-based neurocognitive assessment battery and present a normative data set for future use.

METHODS

A total of 781 participants completed a portion of 8 tasks that captured performance in auditory processing, visual-spatial working memory, visual-spatial learning, cognitive flexibility, and emotional processing. A subset of individuals (n=195) completed a 5-question survey measuring the acceptability of the tasks.

RESULTS

Between 252 and 426 participants completed each task. Younger individuals outperformed their older counterparts in 6 of the 8 tasks. Therefore, central tendency data metrics were presented using 7 different age bins. The broad majority of participants found the tasks interesting and enjoyable and endorsed some interest in playing them at home. Only 1 of 195 individuals endorsed not at all for the statement, "I understood the instructions." Older individuals were less likely to understand the instructions; however, 72% (49/68) of individuals over the age of 60 years still felt that they mostly or very much understood the instructions.

CONCLUSIONS

Overall, the tasks were found to be widely acceptable to the participants. The use of web-based neurocognitive tasks such as these may increase the ability to deploy precise data-informed interventions to a wider population.

Strategy Use Mediates the Relation between Openness to Experience and Episodic Memory in Younger and Older Adults

Previous research has shown that people with higher levels of Openness to Experience show higher levels of cognitive functioning. However, the mechanisms underlying this personality-cognition relation are not well understood. The goal of the current project was to examine whether strategy use mediates the relation between Openness to experience and retrospective memory, and whether the role of strategy use in the Openness-memory relation was the same in younger and older adults.

METHOD

Two studies were conducted. In each of them, younger and older adults were administered a retrospective memory task (29 younger and 27 older in Study 1, 43 adults of all ages in Study 2). They were asked to report the strategies they used during the task, and to complete an Openness to Experience scale.

RESULTS

Consistent with previous reports, higher scores of Openness to experience and greater use of efficient memory strategies were associated with higher levels of memory performance. In addition, individual differences in memory strategy use mostly mediated the relation between Openness and memory performance. Results did not support a mediation model moderated by age. That is, the role of memory strategy use in the relation between Openness and memory was the same in younger and older adults.

CONCLUSION

Higher levels of Openness are associated with better memory performance, mostly because people with higher levels of Openness use more efficient memory strategies.

Strategic encoding and retrieval processes in verbal recall among middle-aged and older adults

The authors used an analysis of individual differences to examine the role of executive control in strategic encoding and retrieval in verbal recall. Participants enrolled in the Louisiana Healthy Aging Study completed measures of working memory (WM), cognitive status, vocabulary, and free recall of words. Indices of clustering in free recall were calculated to permit inferences on strategic encoding and retrieval processes. We hypothesized that WM would be more strongly associated with strategic encoding and retrieval metrics than vocabulary based on the assumption that successful remembering requires executive control in WM. Regression analyses, together with a variance portioning procedure, confirmed that WM had comparable levels of unique and shared variance with the strategic encoding and retrieval metrics, and both exceeded vocabulary. Theoretical and clinical implications of these data are considered, with the suggestion of future research in lifespan samples as opposed to exclusively young adult or older adult samples.

What eye movements reveal about strategy encoding of words in younger and older adults

The main goal of this study was to explore the organizational strategies used by younger and older adults when encoding words, using eye-tracking. Participants had to learn a set of organizable words and then a set of non-organizable words, each presented on a single display. Participants were then asked to recall the words of each set in the order in which they came to their mind. Hence, the participants' encoding strategies revealed by eye-tracking could be directly related to their subsequent memory performance. The results confirmed the detrimental impact of aging on memory and the weaker use of organizational strategies by older adults during the recall phase. The eye-tracking data showed that when they encode the words, older adults do not look at them for as long as younger adults, probably because of slower eye movements. They also revealed that compared to younger adults, older adults were much less able to adapt their word scanning strategy according to whether the words to encode were organizable or not. Finally, the relationships that were found between the recall scores and the eye-tracking data suggest that the eye movement pattern at learning can predict how people will recall the words.

Strategy use and verbal memory in older adults: The role of intellectual functioning and the preferential impact of semantic clustering

Objective: The relative importance of various mechanisms supporting declarative verbal memory among older adults remains uncertain. The present study examined the impact of strategy use (specifically semantic clustering) versus other variables known to impact memory performance (age, sex, education, FSIQ, processing speed, and executive functioning) on verbal memory functioning among healthy older adults.Methods: Healthy older adults from the California Verbal Learning Test, Second Edition standardization sample were selected (N = 242). Relationships between verbal memory, demographics variables, and neuropsychological factors were established, and a hierarchical regression analysis was conducted to examine the individual contributions of these variables in predicting memory performance.Results: Bivariate correlations suggested that memory was significantly related to demographic factors, IQ, executive functioning, and semantic clustering. Importantly, hierarchical regression analysis revealed that semantic clustering significantly and independently contributed to recall performance beyond the demonstrated impacts of FSIQ, speed, executive functioning, and demographic variables. Furthermore, FSIQ did not moderate the relationship between semantic clustering and memory indicating that this strategy is an important factor in bolstering recall, independent of FSIQ.Conclusions: Our results highlight the critical importance of semantic clustering utilization in enhancing memory performance among healthy older adults.

Executive functions in schizophrenia aging: Differential effects of age within specific executive functions

There are common cognitive and brain abnormalities in schizophrenia and healthy aging which may cumulate in schizophrenia aging. However, the course of executive deficits in late-life schizophrenia is still controversial as it remains unclear whether schizophrenia patients show accelerated aging. The use of specific models of executive functions might help to shed new lights on this issue. The aim of this study was then to determine how each of the four specific executive functions (shifting, updating, inhibition and access to long-term memory) is affected by aging in schizophrenia compared to healthy aging. 20 younger (age 18-34), 17 middle-aged (age 35-49) and 25 older (age 59-76) schizophrenia patients and 62 healthy comparison participants matched for gender, age and education performed a neurocognitive battery evaluating the four specific executive functions. Schizophrenia patients performed worse than comparison participants on shifting, updating and access, whereas inhibition appeared preserved. Age affected the four functions with increased degradation of shifting and access in schizophrenia patients, whereas updating and inhibition showed a normal decline with age. These results suggest a vulnerability of prefrontal and cingulate cortexes in schizophrenia aging. Moreover, as age affected the specific executive functions differently, remediation programs should be adapted to older patients. Models of specific executive functions are useful for understanding the complexity of cognition in schizophrenia and its course during later life so that healthcare can be adapted accordingly.

Differences in Semantic Memory Encoding Strategies in Young, Healthy Old and MCI Patients

Associative processes, such as the encoding of associations between words in a list, can enhance episodic memory performance and are thought to deteriorate with age. Here, we examine the nature of age-related deficits in the encoding of associations, by using a free recall paradigm with visual arrays of objects. Fifty-five participants (26 young students; 20 cognitive healthy older adults; nine patients with Mild Cognitive Impairment, MCI) were shown multiple slides (experimental trials), each containing an array of nine common objects for recall. Most of the arrays contained three objects from three semantic categories, each. In the remaining arrays, the nine objects were unrelated. Eye fixations were also monitored during the viewing of the arrays, in a subset of the participants. While for young participants the immediate recall was higher for the semantically related arrays, this effect was diminished in healthy elderly and totally absent in MCI patients. Furthermore, only in the young group did the sequence of eye fixations show a semantic scanning pattern during encoding, even when the related objects were non- adjacent in the array. Healthy elderly and MCI patients were not influenced by the semantic relatedness of items during the array encoding, to the same extent as young subjects, as observed by a lack of (or reduced) semantic scanning. The results support a version of the encoding of the association aging-deficit hypothesis.

Associations between sleep and verbal memory in subjective cognitive decline: A role for semantic clustering

Age-related reductions in slow wave activity (SWA) and increased fragmentation during sleep play a key role in memory impairment. As the prefrontal cortex is necessary for the control processes relevant to memory encoding, including utilisation of internal heuristics such as semantic clustering, and is preferentially vulnerable to sleep disturbance, our study examined how SWA and sleep fragmentation relates to memory performance in individuals with Subjective Cognitive Decline (SCD). Thirty older adults with SCD (Mean Age = 69.34, SD = 5.34) completed a neurocognitive test battery, including the California Verbal Learning Test, which was used to assess semantic clustering. One week later, participants were admitted to the laboratory for a two night visit. SWA and sleep fragmentation were captured using sleep polysomnography. Next-day memory performance was tested using the Rey Auditory Verbal Learning Test. Poorer sleep (reduced SWA; increased arousals) was associated with reduced semantic clustering, which mediated impairment on verbal memory and learning tests conducted both the day after sleep was recorded (for both SWA and arousals), and a week prior (for arousals only). We demonstrate semantic clustering mediated the well described associations between sleep and verbal memory. As these strategies are a component of cognitive training interventions, future research may examine the role of simultaneous sleep interventions for improving cognitive training outcomes.

Optimizing memory strategy use in young and older adults: The role of metamemory and internal strategy use

We explored whether experiencing differential efficacy of reading and generation for memory in an initial learning trial led younger and older adults to improve recall of read items in a subsequent learning trial, leading to a reduction of the generation effect. In the first trial, generation improved the memory performance of both young and older adults. However, in Trial 2, the generation effect remained significant for older adults only, confirming that they did not change the way they processed read items, unlike the young adults. The older adults were also less spontaneously aware that generation led to better memory performance in the first trial, and, in contrast to the young adults, awareness did not result in a reduction of the generation effect. Moreover, the age-related differences in generation effect reduction were mediated by an independent measure of self-reported internal strategy use. However, when an appropriate environmental support was provided between both trials, older adults improved read items recall at the second trial as well as younger ones, leading to an elimination of the generation advantage for both groups. Environmental support reduced the implication of internal strategy use in the generation effect reduction, suggesting that age-related differences in the implementation of effective encoding processes in Trial 2 would be the consequence of a metamemory deficit, and reduced capacity to self-initiate internal strategies.

Age-Related Deficits in Memory Encoding and Retrieval in Word List Free Recall

Although ageing is known to affect memory, the precise nature of its effect on retrieval and encoding processes is not well understood. Here, we examine the effect of ageing on the free recall of word lists, in which the semantic structure of word sequences was manipulated from unrelated words to pairs of associated words with various separations (between pair members) within the sequence. We find that ageing is associated with reduced total recall, especially for sequences with associated words. Furthermore, we find that the degree of semantic clustering (controlled for chance clustering) shows an age effect and that it interacts with the distance between the words within a pair. The results are consistent with the view that age effects in memory are mediated both by retrieval and by encoding processes associated with frontal control and working memory.

Memory flexibility training for autobiographical memory as an intervention for maintaining social and mental well-being in older adults

Autobiographical memory specificity (AMS) reduces with increasing age and is associated with depression, social problem-solving and functional limitations. However, ability to switch between general and specific, as well as between positive and negative retrieval, may be more important for the strategic use of autobiographical information in everyday life. Ability to switch between retrieval modes is likely to rely on aspects of executive function. We propose that age-related deficits in cognitive flexibility impair AMS, but the "positivity effect" protects positively valenced memories from impaired specificity. A training programme to improve the ability to flexibly retrieve different types of memories in depressed adults (MemFlex) was examined in non-depressed older adults to determine effects on AMS, valence and the executive functions underlying cognitive flexibility. Thirty-nine participants aged 70+ (MemFlex, n = 20; control, n = 19) took part. AMS and the inhibition aspect of executive function improved in both groups, suggesting these abilities are amenable to change, although not differentially affected by this type of training. Lower baseline inhibition scores correlated with increased negative, but not positive AMS, suggesting that positive AMS is an automatic process in older adults. Changes in AMS correlated with changes in social problem-solving, emphasising the usefulness of AMs in a social environment.

Gamma oscillatory activity is impaired in episodic memory encoding with age

The present study proposes to investigate age-related episodic memory impairment in encoding. We collected ERPs in young and old participants performing a word-encoding task. For subsequently remembered words, young adults had greater activity at the left and anterior electrode sites, whereas old adults had greater posterior activity. Performance correlated positively with central sites in young adults but with left parietal hemisphere activity in old adults. Plus, a large left frontoparietal network increased its activity during the successful encoding for the Beta (13-30 Hz) and Gamma (30-100 Hz) bands in young adults. Old adults had increased activity in the right posterior parietal region for forgotten words in the Gamma band. Using a source localization analysis, we found that age leads to a decrease in Gamma band cerebral activity during encoding of words in the left hemisphere and the bilateral parahippocampal regions. These findings indicate that encoding impairment with age may be associated with dysfunctional Gamma oscillatory activity across a widespread network of left cortical regions.

Episodic memory in normal aging and Alzheimer disease: Insights from imaging and behavioral studies

Age-related cognitive changes often include difficulties in retrieving memories, particularly those that rely on personal experiences within their temporal and spatial contexts (i.e., episodic memories). This decline may vary depending on the studied phase (i.e., encoding, storage or retrieval), according to inter-individual differences, and whether we are talking about normal or pathological (e.g., Alzheimer disease; AD) aging. Such cognitive changes are associated with different structural and functional alterations in the human neural network that underpins episodic memory. The prefrontal cortex is the first structure to be affected by age, followed by the medial temporal lobe (MTL), the parietal cortex and the cerebellum. In AD, however, the modifications occur mainly in the MTL (hippocampus and adjacent structures) before spreading to the neocortex. In this review, we will present results that attempt to characterize normal and pathological cognitive aging at multiple levels by integrating structural, behavioral, inter-individual and neuroimaging measures of episodic memory.

Processes in arithmetic strategy selection: a fMRI study

This neuroimaging (functional magnetic resonance imaging) study investigated neural correlates of strategy selection. Young adults performed an arithmetic task in two different conditions. In both conditions, participants had to provide estimates of two-digit multiplication problems like 54 × 78. In the choice condition, participants had to select the better of two available rounding strategies, rounding-up (RU) strategy (i.e., doing 60 × 80 = 4,800) or rounding-down (RD) strategy (i.e., doing 50 × 70 = 3,500 to estimate product of 54 × 78). In the no-choice condition, participants did not have to select strategy on each problem but were told which strategy to use; they executed RU and RD strategies each on a series of problems. Participants also had a control task (i.e., providing correct products of multiplication problems like 40 × 50). Brain activations and performance were analyzed as a function of these conditions. Participants were able to frequently choose the better strategy in the choice condition; they were also slower when they executed the difficult RU than the easier RD. Neuroimaging data showed greater brain activations in right anterior cingulate cortex (ACC), dorso-lateral prefrontal cortex (DLPFC), and angular gyrus (ANG), when selecting (relative to executing) the better strategy on each problem. Moreover, RU was associated with more parietal cortex activation than RD. These results suggest an important role of fronto-parietal network in strategy selection and have important implications for our further understanding and modeling cognitive processes underlying strategy selection.

Negative neuroplasticity in chronic traumatic brain injury and implications for neurorehabilitation

Based on growing findings of brain volume loss and deleterious white matter alterations during the chronic stages of injury, researchers posit that moderate-severe traumatic brain injury (TBI) may act to “age” the brain by reducing reserve capacity and inducing neurodegeneration. Evidence that these changes correlate with poorer cognitive and functional outcomes corroborates this progressive characterization of chronic TBI. Borrowing from a framework developed to explain cognitive aging (Mahncke et al., Progress in Brain Research, 157, 81–109, 2006a; Mahncke et al., Proceedings of the National Academy of Sciences of the United States of America, 103(33), 12523–12528, 2006b), we suggest here that environmental factors (specifically environmental impoverishment and cognitive disuse) contribute to a downward spiral of negative neuroplastic change that may modulate the brain changes described above. In this context, we review new literature supporting the original aging framework, and its extrapolation to chronic TBI. We conclude that negative neuroplasticity may be one of the mechanisms underlying cognitive and neural decline in chronic TBI, but that there are a number of points of intervention that would permit mitigation of this decline and better long-term clinical outcomes.

Inhibition and shifting capacities mediate adults' age-related differences in strategy selection and repertoire

Young and older adults differ in how many strategies they use to accomplish cognitive tasks. They also differ in how often they select the best strategy on each problem. Two experiments were run to determine whether two executive functions-inhibition and shifting capacities-mediate age-related differences in strategy repertoire and in strategy selection. Both experiments were run in arithmetic problem solving. In Experiment 1, young and older adults' strategy repertoire was assessed on a problem-by-problem basis while participants solved two-digit addition problems (e.g., 42+76). In Experiment 2, young and older participants had to select the best strategy on each problem to find estimates of two-digit multiplication problems (e.g., 43×72). In both experiments, individuals' inhibition and shifting capacities were assessed with the Trail Making Test and the Stroop Test. The main results showed that (a) older adults used a smaller strategy repertoire (Expt. 1) and selected the best strategy on each problem less frequently (Expt. 2) than young adults, (b) inhibition and shifting capacities mediated age-related differences in strategy repertoire and strategy selection, and unique age effects were no longer significant in strategy repertoire but were still significant in strategy selection after statistical control of inhibition and shifting capacities. We discuss important implications of these findings to further our understanding of strategic variations during cognitive aging.

Age differences in the perception of hierarchical structure in events

Everyday activities break down into parts and subparts, and appreciating this hierarchical structure is an important component of understanding. In two experiments we found age differences in the ability to perceive hierarchical structure in continuous activity. In both experiments, younger and older adults segmented movies of everyday activities into large and small meaningful events. Older adults' segmentation deviated more from group norms than did younger adults' segmentation, and older adults' segmentation was less hierarchically organized than that of younger adults. Older adults performed less well than younger adults on event memory tasks. In some cases, measures of event segmentation discriminated between those older adults with better and worse memory. These results suggest that the hierarchical encoding of ongoing activity declines with age, and that such encoding may be important for memory.

Cognitive predictors of everyday functioning in older adults: results from the ACTIVE Cognitive Intervention Trial

OBJECTIVE

The present study sought to predict changes in everyday functioning using cognitive tests.

METHODS

Data from the Advanced Cognitive Training for Independent and Vital Elderly trial were used to examine the extent to which competence in different cognitive domains--memory, inductive reasoning, processing speed, and global mental status--predicts prospectively measured everyday functioning among older adults. Coefficients of determination for baseline levels and trajectories of everyday functioning were estimated using parallel process latent growth models.

RESULTS

Each cognitive domain independently predicts a significant proportion of the variance in baseline and trajectory change of everyday functioning, with inductive reasoning explaining the most variance (R2 = .175) in baseline functioning and memory explaining the most variance (R2 = .057) in changes in everyday functioning.

DISCUSSION

Inductive reasoning is an important determinant of current everyday functioning in community-dwelling older adults, suggesting that successful performance in daily tasks is critically dependent on executive cognitive function. On the other hand, baseline memory function is more important in determining change over time in everyday functioning, suggesting that some participants with low baseline memory function may reflect a subgroup with incipient progressive neurologic disease.

Developmental differences in explicit and implicit conceptual memory tests: a processing view account

The present study addressed contradictory results in childhood literature about conceptual priming. Based on the processing view, two forms of conceptual priming were investigated across two experiments in children aged from 7 to 16: associative priming (using the free-association test) and relational (categorical) priming (using the categorical exemplar generation test) as well as their explicit memory measure counterparts (the associative-cued recall and the category-cued recall). Experiment 1 compared age differences in associative and relational (categorical) priming. Experiment 2 focused on relational (categorical) priming with manipulations of blocked/unblocked words per category. The results showed that (a) associative priming was unchanged in children aged from 7 to 16, whereas relational (categorical) priming improved from 7-9 to 13-16 years old, and (b) age differences in relational (categorical) priming still occurred under unblocked conditions and blocked condition, while age differences in explicit measures were reduced under blocked conditions. These findings were discussed in line with the debate between the system and processing view and in terms of knowledge and automaticity development.

Cognitive Strategy Variations During Aging

The last two decades of research in cognitive aging have seen a shift from simply describing age-related changes in cognitive performance to determining the mechanisms underlying these changes. Recent findings on variations in the use of cognitive strategies during aging further our understanding of how these changes in performance occur during adulthood. Data show age-related differences in strategy repertoire, strategy distribution, strategy execution, and strategy selection. I illustrate these findings in cognitive domains as varied as episodic memory, working memory, reasoning, decision making, problem solving, and language. I discuss how strategic variations are best studied both conceptually and methodologically and how investigating strategic variations helps us make significant progress in the study of cognitive aging. As I also show in this article, whichever the cognitive domain being studied, there are no restrictions that would prevent us from adopting a strategy perspective.

Aging and self-reported internal and external memory strategy uses: the role of executive functioning

The aim of this study was to investigate the effect of advanced age on self-reported internal and external memory strategy uses, and whether this effect can be predicted by executive functioning. A sample of 194 participants aged 21 to 80 divided into three age groups (21-40, 41-60, 61-80) completed the two strategy scales of the Metamemory in Adulthood (MIA) questionnaire, differentiating between internal and external everyday memory strategy uses, and three tests of executive functioning. The results showed that: (1) the use of external memory strategies increased with age, whereas use of internal memory strategy decreased; (2) executive functioning appeared to be related only to internal strategies, the participants who reported the greatest use of internal strategies having the highest executive level; and (3) executive functioning accounted for a sizeable proportion of the age-related variance in internal strategy use. These findings suggest that older adults preferentially use external memory strategies to cope with everyday memory impairment due to aging. They also support the view that the age-related decrease in the implementation of internal memory strategies can be explained by the executive hypothesis of cognitive aging. This result parallels those observed using objective laboratory memory strategy measures and then supports the validity of self-reported memory strategy questionnaire.

Episodic memory and organizational strategy in free recall in unipolar depression: the role of cognitive support and executive functions

Executive functioning and memory impairment have been demonstrated in adults with depression. Executive functions and memory are related, mainly when the memory tasks require controlled processes (attentional resource demanding processes)--that is, when a low cognitive support (external aid) is provided. A cross-sectional study was carried out on 45 participants: 21 with depression, and 24 healthy controls matched for age, verbal ability, education level, and anxiety score. Cognitive support was manipulated by providing a categorized word list at encoding, presented either clustered (high cognitive support) or randomized (low cognitive support) to both depressed and healthy adults. The number of words recalled was calculated, and an index of clustering was computed to assess organizational strategies. Participants were also administered cognitive tests (executive functions, cognitive speed, and categorical fluency) to explore the mediators of organizational strategies. Depressed participants had greater difficulty recalling and organizing the words, but the differences between the two groups were reduced for both measures when high cognitive support was provided at encoding. Healthy adults performed better on all cognitive tests. Statistical analyses revealed that in the depressed group, executive functions were the only variable associated with clustering and only when low cognitive support was provided. These findings support the view that the decrement in executive function due to depression may lead to impairment in organization when this mnemonic strategy has to be self-initiated.