Recollection Training and Transfer Effects in Older Adults: Successful Use of a Repetition-Lag Procedure

Null cross-modal effects of olfactory training on visual, auditory or olfactory working memory in 6- to 9-year-old children

Systematic exposure to odours (olfactory training, OT) is a method of smell loss treatment. Due to olfactory system projections to prefrontal brain areas, OT has been hypothesized to enhance cognitive functions, but its effects have been studied predominantly in adults. This study tested OT effects on working memory (WM), i.e., the ability to store and manipulate information for a short time, in healthy children aged 6-9 years. We expected OT to improve olfactory WM and establish cross-modal transfer to visual and auditory WM. Participants performed 12 weeks of bi-daily OT with either 4 odours (lemon, eucalyptus, rose, cloves; OT group) or odourless propylene glycol (placebo group). Pre- and post-training, participants' WM was measured utilizing odours (olfactory WM) or pictures (visual WM) and a word-span task (auditory WM). 84 children (40 girls) completed the study. The analyses revealed no changes in the WM performance following OT. The olfactory WM task was the most difficult for children, highlighting the need to include olfactory-related tasks in educational programmes to improve children's odour knowledge and memory, just as they learn about sounds and pictures. Further neuroimaging research is needed to fully understand the impact of OT on cognitive functions in children.

Training semantic long-term memory retrieval transfers to executive function and reading fluency

The retrieval of information from long-term memory is a fundamental cognitive ability, crucial for most aspects of successful human functioning. Whether and how long-term memory retrieval (LTMR) can be improved with training has clear societal importance but also theoretical value for furthering our understanding of underlying mechanisms. Here, we provide electrophysiological evidence for the plasticity of semantic LTMR. Thirty-five university students were randomly assigned to adaptive semantic LTMR training (using a Posner task) or to a non-adaptive version of the training. Before and after training they were assessed on measures of semantic LTMR, working memory, central executive function (interference control, switching), reading fluency, and fluid intelligence. Adaptive LTMR training (relative to non-adaptive training) led to significant improvements in semantic LTMR. The intervention group (in contrast to the control group) also showed a significant reduction in the mean amplitude of the N400 ERP component and 700-1000 ms measured during a semantic LTMR task, suggesting that changes in retrieval occurred at an early/automatic point and retrieval processing in semantic processing. Moreover, transfer effects were observed for switching, working memory and reading fluency, but not for interference control or fluid intelligence. These results point to the plasticity of semantic LTMR, and suggest that improvement in this ability can transfer to other domains for which LTMR is key.

Examining the influence of brain stimulation to the medial prefrontal cortex on the self-reference effect in memory

Past work shows that processing information in relation to the self improves memory which is known as the self-reference effect in memory. Other work suggests that transcranial direct current stimulation (tDCS) can also improve memory. Given recent research on self-reference context memory effects (improved memory for contextual episodic details associated with self-referential processing), we were interested in examining the extent stimulation might increase the magnitude of the self-reference context memory effect. In this investigation, participants studied objects superimposed on different background scenes in either a self-reference or other-reference condition while receiving either active or sham stimulation to the dorsal medial prefrontal cortex (dmPFC), a cortical region known to support self-reference context memory effects. Participants then completed a memory test that assessed item memory (have you seen this object before?) and context memory (with which background scene was this object paired?). Results showed a self-reference context memory effect driven by enhanced memory for stimuli processed in the self-reference compared to the other-reference condition across all participants (regardless of stimulation condition). tDCS, however, had no effect on memory. Specifically, stimulation did not increase the magnitude of the self-reference context memory effect under active compared to sham stimulation. These results suggest that stimulation of the dmPFC at encoding may not add to the memory benefits induced by self-referential processing suggesting a boundary condition to tDCS effects on memory.

STOP SHOUTING AT ME: The Influence of Case and Self-Referencing on Explicit and Implicit Memory

Evidence suggests that physical changes in word appearance, such as those written in all capital letters, and the use of effective encoding strategies, such as self-referential processing, improves memory. In this study we examined the extent both physical changes in word appearance (case) and encoding strategies engaged at study influence memory as measured by both explicit and implicit memory measures. Participants studied words written in upper and lower case under three encoding conditions (self-reference, semantic control, case judgment), which was followed by an implicit (word stem completion) and then an explicit (item and context) memory test. There were two primary results. First, analyses indicated a case enhancement effect for item memory where words written in upper case were better remembered than lower case, but only when participants were prompted to attend to the case of the word. Importantly, this case enhancement effect came at a cost to context memory for words written in upper case. Second, self-referencing increased explicit memory performance relative to control, but there was no effect on implicit memory. Overall, results suggest an item-context memory trade-off for words written in upper case, highlighting a potential downside to writing in all capital letters, and further, that both physical changes to the appearance of words and differing encoding strategies have a strong influence on explicit, but not implicit memory.

Characterizing developmental prosopagnosia beyond face perception: Impaired recollection but intact familiarity recognition

Converging lines of research suggests that many developmental prosopagnosics (DPs) have impairments beyond face perception, but currently no framework exists to characterize these impaired mechanisms. One potential extra-perceptual deficit is that DPs encode/retrieve faces in a distinct manner from controls that does not sufficiently support individuation. To test this possibility, 30 DPs and 30 matched controls performed an old/new face recognition task while providing confidence ratings, to which a model-based ROC analysis was applied. DPs had significantly reduced recollection compared to controls, driven by fewer 'high-confidence target' responses, but intact familiarity. Recollection and face perception ability uniquely predicted objective and subjective prosopagnosia symptoms, together explaining 51% and 56% of the variance, respectively. These results suggest that a specific deficit in face recollection in DP may represent a core aspect of the difficulty in confidently identifying an individual by their face.

When Gist and Familiarity Collide: Evidence From False Recognition in Younger and Older Adults

OBJECTIVES

Aging is associated with decreased recollection required to offset misleading effects of familiarity, as well as an increased mnemonic reliance on gist-based over detail-based information. We tested the novel hypothesis that age-related decrements in overriding familiarity can be eliminated under conditions in which gist-based information facilitates retrieval.

METHOD

Twenty-seven younger adults and 27 older adults viewed scenes from two categories in an incidental encoding phase. In a recognition phase, old scenes were intermixed with new scenes from the studied categories and an unstudied category, with each new scene reappearing after 4, 18, or 48 intervening scenes. Participants were to respond "yes" to old scenes, and "no" to new scenes, including their repetitions.

RESULTS

Despite encoding the scenes similarly, older adults made more false endorsements of new and repeated new scenes from studied categories. Both groups, however, were equally unlikely to falsely recognize new and repeated new scenes from the unstudied category.

DISCUSSION

When helpful gist and misleading familiarity collide, gist wins, and eliminates age-related increases in false recognition.

Activating Developmental Reserve Capacity Via Cognitive Training or Non-invasive Brain Stimulation: Potentials for Promoting Fronto-Parietal and Hippocampal-Striatal Network Functions in Old Age

Existing neurocomputational and empirical data link deficient neuromodulation of the fronto-parietal and hippocampal-striatal circuitries with aging-related increase in processing noise and declines in various cognitive functions. Specifically, the theory of aging neuronal gain control postulates that aging-related suboptimal neuromodulation may attenuate neuronal gain control, which yields computational consequences on reducing the signal-to-noise-ratio of synaptic signal transmission and hampering information processing within and between cortical networks. Intervention methods such as cognitive training and non-invasive brain stimulation, e.g., transcranial direct current stimulation (tDCS), have been considered as means to buffer cognitive functions or delay cognitive decline in old age. However, to date the reported effect sizes of immediate training gains and maintenance effects of a variety of cognitive trainings are small to moderate at best; moreover, training-related transfer effects to non-trained but closely related (i.e., near-transfer) or other (i.e., far-transfer) cognitive functions are inconsistent or lacking. Similarly, although applying different tDCS protocols to reduce aging-related cognitive impairments by inducing temporary changes in cortical excitability seem somewhat promising, evidence of effects on short- and long-term plasticity is still equivocal. In this article, we will review and critically discuss existing findings of cognitive training- and stimulation-related behavioral and neural plasticity effects in the context of cognitive aging, focusing specifically on working memory and episodic memory functions, which are subserved by the fronto-parietal and hippocampal-striatal networks, respectively. Furthermore, in line with the theory of aging neuronal gain control we will highlight that developing age-specific brain stimulation protocols and the concurrent applications of tDCS during cognitive training may potentially facilitate short- and long-term cognitive and brain plasticity in old age.

No Evidence for Improved Associative Memory Performance Following Process-Based Associative Memory Training in Older Adults

Studies attempting to improve episodic memory performance with strategy instructions and training have had limited success in older adults: their training gains are limited in comparison to those of younger adults and do not generalize to untrained tasks and contexts. This limited success has been partly attributed to age-related impairments in associative binding of information into coherent episodes. We therefore investigated potential training and transfer effects of process-based associative memory training (i.e., repeated practice). Thirty-nine older adults (M_age = 68.8) underwent 6 weeks of either adaptive associative memory training or item recognition training. Both groups improved performance in item memory, spatial memory (object-context binding) and reasoning. A disproportionate effect of associative memory training was only observed for item memory, whereas no training-related performance changes were observed for associative memory. Self-reported strategies showed no signs of spontaneous development of memory-enhancing associative memory strategies. Hence, the results do not support the hypothesis that process-based associative memory training leads to higher associative memory performance in older adults.

Repetition-lag memory training is feasible in patients with chronic stroke, including those with memory problems

PRIMARY OBJECTIVE

Repetition-lag memory training was developed to increase individuals' use of recollection as opposed to familiarity in recognition memory. The goals of this study were to examine the feasibility of repetition-lag training in patients with chronic stroke and to explore whether the training might show suggestions of transfer to non-trained tasks.

RESEARCH DESIGN

Quasi-experimental.

METHODS AND PROCEDURES

Patients (n = 17) took part in six repetition-lag training sessions and their gains on the training and non-trained tasks were compared to those of age-matched healthy controls (n = 30).

MAIN OUTCOMES AND RESULTS

All but two patients completed the training, indicating that the method is feasible with a wide range of patients with stroke. The amount patients gained on the training task was similar to that of healthy controls (that is, the Group × Time interactions were by-and-large not significant), suggesting that patients with stroke might benefit to the same degree as healthy adults from this training. Both groups showed some indication of transfer to the non-trained backward digit span task and visuospatial memory.

CONCLUSIONS

These findings show that repetition-lag memory training is a possible approach with patients with stroke to enhance recollection. Further research on the method's efficacy and effectiveness is warranted.

You can go your own way: effectiveness of participant-driven versus experimenter-driven processing strategies in memory training and transfer

Cognitive training programs that instruct specific strategies frequently show limited transfer. Open-ended approaches can achieve greater transfer, but may fail to benefit many older adults due to age deficits in self-initiated processing. We examined whether a compromise that encourages effort at encoding without an experimenter-prescribed strategy might yield better results. Older adults completed memory training under conditions that either (1) mandated a specific strategy to increase deep, associative encoding, (2) attempted to suppress such encoding by mandating rote rehearsal, or (3) encouraged time and effort toward encoding but allowed for strategy choice. The experimenter-enforced associative encoding strategy succeeded in creating integrated representations of studied items, but training-task progress was related to pre-existing ability. Independent of condition assignment, self-reported deep encoding was associated with positive training and transfer effects, suggesting that the most beneficial outcomes occur when environmental support guiding effort is provided but participants generate their own strategies.

Training for generalization in Theory of Mind: a study with older adults

Theory of Mind (ToM) refers to the ability to attribute independent mental states to self and others in order to explain and predict social behavior. Recent research in this area has shown a decline in ToM abilities associated with normal aging that is of a moderate magnitude or greater. Very few studies have investigated whether it is possible to improve older adults’ ToM abilities. The present study was designed to address this gap in the literature by evaluating the impact of a ToM training on practiced and transfer tasks. We provided older adults with a variety of activities designed to facilitate the generalization of benefits to other ToM-demanding tasks. Participants were 63 healthy older adults, native Italian speakers (M_age = 71.44, SD = 5.24, age range: 63–81 years). Participants were randomly assigned to one of two groups: the ToM training (age range: 63–81 years) and the physical-conversation training (age range: 64–81 years). Training effects were measured using the strange stories (practiced task) and the animation task (transfer task). Results revealed the efficacy of the training in producing improvements on practiced but also on transfer tasks.

Associations Between Ankle-Brachial Index and Cognitive Function: Results From the Lifestyle Interventions and Independence for Elders Trial

OBJECTIVE

The objective of this study was to evaluate cross-sectional and longitudinal associations between ankle-brachial index (ABI) and indicators of cognitive function.

DESIGN

Randomized clinical trial (Lifestyle Interventions and Independence for Elders Trial).

SETTING

Eight US academic centers.

PARTICIPANTS

A total of 1601 adults ages 70-89 years, sedentary, without dementia, and with functional limitations.

MEASUREMENTS

Baseline ABI and interviewer- and computer-administered cognitive function assessments were obtained. These assessments were used to compare a physical activity intervention with a health education control. Cognitive function was reassessed 24 months later (interviewer-administered) and 18 or 30 months later (computer-administered) and central adjudication was used to classify individuals as having mild cognitive impairment, probable dementia, or neither.

RESULTS

Lower ABI had a modest independent association with poorer cognitive functioning at baseline (partial r = 0.09; P < .001). Although lower baseline ABI was not associated with overall changes in cognitive function test scores, it was associated with higher odds for 2-year progression to a composite of either mild cognitive impairment or probable dementia (odds ratio 2.60 per unit lower ABI; 95% confidence interval 1.06-6.37). Across 2 years, changes in ABI were not associated with changes in cognitive function.

CONCLUSION

In an older cohort sedentary individuals with dementia and with functional limitations, lower baseline ABI was independently correlated with cognitive function and associated with greater 2-year risk for progression to mild cognitive impairment or probable dementia.

Training recollection in healthy older adults: clear improvements on the training task, but little evidence of transfer

Normal aging holds negative consequences for memory, in particular for the ability to recollect the precise details of an experience. With this in mind, Jennings and Jacoby (2003) developed a recollection training method using a single-probe recognition memory paradigm in which new items (i.e., foils) were repeated during the test phase at increasingly long intervals. In previous reports, this method has appeared to improve older adults’ performance on several non-trained cognitive tasks. We aimed to further examine potential transfer effects of this training paradigm and to determine which cognitive functions might predict training gains. Fifty-one older adults were assigned to either recollection training (n = 30) or an active control condition (n = 21) for six sessions over 2 weeks. Afterward, the recollection training group showed a greatly enhanced ability to reject the repeated foils. Surprisingly, however, the training and the control groups improved to the same degree in recognition accuracy (d′) on their respective training tasks. Further, despite the recollection group’s significant improvement in rejecting the repeated foils, we observed little evidence of transfer to non-trained tasks (including a temporal source memory test). Younger age and higher baseline scores on a measure of global cognitive function (as measured by the Montreal Cognitive Assessment tool) and working memory (as measured by Digit Span Backward) predicted gains made by the recollection training group members.

Effects of cognitive training with and without aerobic exercise on cognitively demanding everyday activities

We investigated the potential benefits of a novel cognitive-training protocol and an aerobic exercise intervention, both individually and in concert, on older adults' performances in laboratory simulations of select real-world tasks. The cognitive training focused on a range of cognitive processes, including attentional coordination, prospective memory, and retrospective-memory retrieval, processes that are likely involved in many everyday tasks, and that decline with age. Primary outcome measures were 3 laboratory tasks that simulated everyday activities: Cooking Breakfast, Virtual Week, and Memory for Health Information. Two months of cognitive training improved older adults' performance on prospective-memory tasks embedded in Virtual Week. Cognitive training, either alone or in combination with 6 months of aerobic exercise, did not significantly improve Cooking Breakfast or Memory for Health Information. Although gains in aerobic power were comparable with previous reports, aerobic exercise did not produce improvements for the primary outcome measures. Discussion focuses on the possibility that cognitive-training programs that include explicit strategy instruction and varied practice contexts may confer gains to older adults for performance on cognitively challenging everyday tasks.

Repetition-lag training to improve recollection memory in older people with amnestic mild cognitive impairment. A randomized controlled trial

The results of a randomized controlled trial of repetition-lag training in older adults with amnestic mild cognitive impairment (aMCI) are reported. A modified repetition-lag training procedure with extended encoding time and strategy choice was used. The training required discriminating studied words from non-studied lures that were repeated at varying intervals during the test phase. Participants were assessed pre/post using untrained measures of cognition and self-report questionnaires. Primary outcome measures were recall of unrelated word pairs both immediately following presentation and following a delay. Secondary outcomes were a measure of attention, cognitive flexibility, and visual working memory. Participants were also asked to report on the frequency of cognitive failures and mood before and after training. Participants (N = 31) were randomized into either the treatment or a no-contact control group and attended the clinic twice per week over a four week period. Twenty-four participants completed the study (twelve in each group). Results indicated that the training group improved at recalling unrelated word pairs after a delay. There were no significant effects of training on other outcomes, self-reported cognitive failures or mood. The results are discussed along with suggestions for future research.

Performance of a computer-based assessment of cognitive function measures in two cohorts of seniors

BACKGROUND

Computer-administered assessment of cognitive function is being increasingly incorporated in clinical trials; however, its performance in these settings has not been systematically evaluated.

DESIGN

The Seniors Health and Activity Research Program pilot trial (N = 73) developed a computer-based tool for assessing memory performance and executive functioning. The Lifestyle Interventions and Independence for Elders investigators incorporated this battery in a full-scale multicenter clinical trial (N = 1635). We describe relationships that test scores have with those from interviewer-administered cognitive function tests and risk factors for cognitive deficits and describe performance measures (completeness, intraclass correlations [ICC]).

RESULTS

Computer-based assessments of cognitive function had consistent relationships across the pilot and full-scale trial cohorts with interviewer-administered assessments of cognitive function, age, and a measure of physical function. In the Lifestyle Interventions and Independence for Elders cohort, their external validity was further demonstrated by associations with other risk factors for cognitive dysfunction: education, hypertension, diabetes, and physical function. Acceptable levels of data completeness (>83%) were achieved on all computer-based measures; however, rates of missing data were higher among older participants (odds ratio = 1.06 for each additional year; p < 0.001) and those who reported no current computer use (odds ratio = 2.71; p < 0.001). ICCs among clinics were at least as low (ICC < 0.013) as for interviewer measures (ICC < 0.023), reflecting good standardization. All cognitive measures loaded onto the first principal component (global cognitive function), which accounted for 40% of the overall variance.

CONCLUSION

Our results support the use of computer-based tools for assessing cognitive function in multicenter clinical trials of older individuals.

Recollection and familiarity in schizophrenia: a quantitative review

Recognition memory judgments can be based on recollection of qualitative information about an earlier study event or on assessments of stimulus familiarity. Schizophrenia is associated with pronounced deficits in overall recognition memory, and these deficits are highly predictive of global functioning. However, the extent to which these deficits reflect impairments in recollection or familiarity is less well understood. In the current article, we reviewed studies that used remember-know-new, process dissociation, and receiver operating characteristic procedures to investigate recollection and familiarity in schizophrenia. We also performed a quantitative reanalysis of these study results to obtain recollection and familiarity estimates that account for methodological differences between studies. Contrary to previous conclusions that recollection is selectively impaired in schizophrenia, we found evidence for both familiarity and recollection deficits across studies, suggesting multi-focal medial temporal lobe and/or prefrontal cortex dysfunction. The familiarity deficits were more variable with frequent small-to-medium rather than medium-to-large effect sizes, suggesting that familiarity could be potentially used as a compensatory ability, whereas recollection is conceptualized as a therapeutic target for new treatment development.

The process-dissociation approach two decades later: convergence, boundary conditions, and new directions

The process-dissociation procedure was developed to separate the controlled and automatic contributions of memory. It has spawned the development of a host of new measurement approaches and has been applied across a broad range of fields in the behavioral sciences, ranging from studies of memory and perception to neuroscience and social psychology. Although it has not been without its shortcomings or critics, its growing influence attests to its utility. In the present article, we briefly review the factors motivating its development, describe some of the early applications of the general method, and review the literature examining its underlying assumptions and boundary conditions. We then highlight some of the specific issues that the methods have been applied to and discuss some of the more recent applications of the procedure, along with future directions.

Structural integrity of the corpus callosum predicts long-term transfer of fluid intelligence-related training gains in normal aging

Although cognitive training usually improves cognitive test performance, the capability to transfer these training gains into respective or functionally related cognitive domains varies significantly. Since most studies demonstrate rather limited transfer effects in older adults, aging might be an important factor in transfer capability differences. This study investigated the transfer capability of logical reasoning training gains to a measure of Fluid Intelligence (Gf) in relation to age, general intelligence, and brain structural integrity as measured by diffusion tensor imaging. In a group of 41 highly educated healthy elderly, 71% demonstrated successful transfer immediately after a 4-week training session (i.e. short-term transfer). In a subgroup of 22% of subjects transfer maintained over a 3-month follow-up period (i.e. long-term transfer). While short-term transfer was not related to structural integrity, long-term transfer was associated with increased structural integrity in corpus and genu of the corpus callosum. Since callosal structural integrity was also related to age (in the present and foregoing studies), previously observed associations between age and transfer might be moderated by the structural integrity. Surprisingly, age was not directly associated with transfer in this study which could be explained by the multi-dependency of the structural integrity (modulating factors beside age, e.g. genetics). In this highly educated sample, general intelligence was not related to transfer suggesting that high intelligence is not sufficient for transfer in normal aging. Further studies are needed to reveal the interaction of transfer, age, and structural integrity and delineate mechanisms of age-dependent transfer capabilities.

Differential trajectories of age-related changes in components of executive and memory processes

Several studies have demonstrated age-related declines in general executive function and memory. In this study, we examined cross-sectional and longitudinal age effects in more specific cognitive processes that constitute executive function and memory. We postulated that, whereas some components of executive and memory functions would show age differences and longitudinal declines, other specific abilities would be maintained or even improve with repeated testing. In a sample of individuals ≥55 years old from the Baltimore Longitudinal Study of Aging, we found longitudinal declines in inhibition, manipulation, semantic retrieval, phonological retrieval, switching, and long-term memory over a maximum of 14 years follow-up. In contrast, abstraction, capacity, chunking, discrimination, and short-term memory were maintained or even improved longitudinally, probably due in part to repeated testing. Moreover, whereas several different abilities were correlated across participants' cross-sectional performance, longitudinal changes in performance showed more heterogeneous trajectories. Finally, compared with cross-sectional performance, longitudinal trajectories showed better distinction between participants with and those without later cognitive impairment. These results show that longitudinal cognitive aging of executive and memory functions is not a uniform process but a heterogeneous one and suggest that certain executive and memory functions remain stable despite age-related declines in other component processes.

Computerized cognitive training with older adults: a systematic review

A systematic review to examine the efficacy of computer-based cognitive interventions for cognitively healthy older adults was conducted. Studies were included if they met the following criteria: average sample age of at least 55 years at time of training; participants did not have Alzheimer's disease or mild cognitive impairment; and the study measured cognitive outcomes as a result of training. Theoretical articles, review articles, and book chapters that did not include original data were excluded. We identified 151 studies published between 1984 and 2011, of which 38 met inclusion criteria and were further classified into three groups by the type of computerized program used: classic cognitive training tasks, neuropsychological software, and video games. Reported pre-post training effect sizes for intervention groups ranged from 0.06 to 6.32 for classic cognitive training interventions, 0.19 to 7.14 for neuropsychological software interventions, and 0.09 to 1.70 for video game interventions. Most studies reported older adults did not need to be technologically savvy in order to successfully complete or benefit from training. Overall, findings are comparable or better than those from reviews of more traditional, paper-and-pencil cognitive training approaches suggesting that computerized training is an effective, less labor intensive alternative.

Cognitive training-related changes in hippocampal activity associated with recollection in older adults

Impairments in the ability to recollect specific details of personally experienced events are one of the main cognitive changes associated with aging. Cognitive training can improve older adults' recollection. However, little is currently known regarding the neural correlates of these training-related changes in recollection. Prior research suggests that the hippocampus plays a central role in supporting recollection in young and older adults, and that age-related changes in hippocampal function may lead to age-related changes in recollection. The present study investigated whether cognitive training-related increases in older adults' recollection are associated with changes in their hippocampal activity during memory retrieval. Older adults' hippocampal activity during retrieval was examined before and after they were trained to use semantic encoding strategies to intentionally encode words. Training-related changes in recollection were positively correlated with training-related changes in activity for old words in the hippocampus bilaterally. Positive correlations were also found between training-related changes in activity in prefrontal and left lateral temporal regions associated with self-initiated semantic strategy use during encoding and training-related changes in right hippocampal activity associated with recollection during retrieval. These results suggest that cognitive training-related improvements in older adults' recollection can be supported by changes in their hippocampal activity during retrieval. They also suggest that age differences in cognitive processes engaged during encoding are a significant contributor to age differences in recollection during retrieval.

Memory Training Interventions: What has been forgotten?

Memory training for older adults often produces gains that are limited to the particular memory tasks encountered during training. We suggest that memory training programs may be misguided by an implicit "generalist" assumption-memory training on a couple of memory tasks will have a positive benefit on memory ability in general. One approach to increase memory-training benefits is to target training for the everyday memory tasks for which older adults struggle. Examples include training retrieval strategies, prospective memory strategies, and strategies for learning and remembering names. Another approach is to design training to foster transfer. Possible elements to improve transfer are increasing the variation that is experienced during the course of training at the level of stimuli and tasks, incorporating "homework" that guides the older adult to become attuned to situations in which the strategies can be applied, and providing older adults with a better understanding of how memory works. Finally, incorporating aerobic exercise into memory training programs may potentiate the acquisition and maintenance of the trained cognitive strategies.

Can cognitive training improve episodic memory?

Neuroscience-inspired approaches to train cognitive abilities are bringing about a paradigm shift in the way scientists view the treatment of memory dysfunction, but it can be challenging to prove whether such approaches have significant effects.

The Lifestyle Interventions and Independence for Elders Study: design and methods

BACKGROUND

As the number of older adults in the United States rises, maintaining functional independence among older Americans has emerged as a major clinical and public health priority. Older people who lose mobility are less likely to remain in the community; demonstrate higher rates of morbidity, mortality, and hospitalizations; and experience a poorer quality of life. Several studies have shown that regular physical activity improves functional limitations and intermediate functional outcomes, but definitive evidence showing that major mobility disability can be prevented is lacking. A Phase 3 randomized controlled trial is needed to fill this evidence gap.

METHODS

The Lifestyle Interventions and Independence for Elders (LIFE) Study is a Phase 3 multicenter randomized controlled trial designed to compare a supervised moderate-intensity physical activity program with a successful aging health education program in 1,600 sedentary older persons followed for an average of 2.7 years.

RESULTS

LIFE's primary outcome is major mobility disability, defined as the inability to walk 400 m. Secondary outcomes include cognitive function, serious fall injuries, persistent mobility disability, the combined outcome of major mobility disability or death, disability in activities of daily living, and cost-effectiveness.

CONCLUSIONS

Results of this study are expected to have important public health implications for the large and growing population of older sedentary men and women.

Tests of the DRYAD theory of the age-related deficit in memory for context: not about context, and not about aging

Older adults exhibit a disproportionate deficit in their ability to recover contextual elements or source information about prior encounters with stimuli. A recent theoretical account, DRYAD, attributes this selective deficit to a global decrease in memory fidelity with age, moderated by weak representation of contextual information. The predictions of DRYAD are tested here in three experiments. We show that an age-related deficit obtains for whichever aspect of the stimulus subjects' attention is directed away from during encoding (Experiment 1), suggesting a central role for attention in producing the age-related deficit in context. We also show that an analogous deficit can be elicited within young subjects with a manipulation of study time (Experiment 2), suggesting that any means of reducing memory fidelity yields an interaction of the same form as the age-related effect. Experiment 3 evaluates the critical prediction of DRYAD that endorsement probability in an exclusion task should vary nonmonotonically with memory strength. This prediction was confirmed by assessing the shape of the forgetting function in a continuous exclusion task. The results are consistent with the DRYAD account of aging and memory judgments and do not support the widely held view that aging entails the selective disruption of processes involved in encoding, storing, or retrieving contextual information.

Memory training impacts short-term changes in aging white matter: a longitudinal diffusion tensor imaging study

A growing body of research indicates benefits of cognitive training in older adults, but the neuronal mechanisms underlying the effect of cognitive intervention remains largely unexplored. Neuroimaging methods are sensitive to subtle changes in brain structure and show potential for enhancing our understanding of both aging- and training-related neuronal plasticity. Specifically, studies using diffusion tensor imaging (DTI) suggest substantial changes in white matter (WM) in aging, but it is not known whether cognitive training might modulate these structural alterations. We used tract-based spatial statistics (TBSS) optimized for longitudinal analysis to delineate the effects of 8 weeks intensive memory training on WM microstructure. 41 participants (mean age 61 years) matched for age, sex and education were randomly assigned to an intervention or control group. All participants underwent MRI-scanning and neuropsychological assessments at the beginning and end of the study. Longitudinal analysis across groups revealed significant increase in frontal mean diffusivity (MD), indicating that DTI is sensitive to WM structural alterations over a 10-week interval. Further, group analysis demonstrated positive effects of training on the short-term changes. Participants in the training group showed a relative increase in fractional anisotropy (FA) compared with controls. Further, a significant relationship between memory improvement and change in FA was found, suggesting a possible functional significance of the reported changes. The training effect on FA seemed to be driven by a relative decrease in radial diffusivity, which might indicate a role for myelin-related processes in WM plasticity.

The locus of the benefits of repetition-lag memory training

The repetition-lag training procedure developed by Jennings and Jacoby (2003 , Neuropsychological Rehabilitation, 14, 417) has been shown to improve older adults' performance in the recognition memory task used for training, and to improve performance in a variety of other memory and executive function tasks ( Jennings, Webster, Kleykamp, & Dagenbach, 2005 , Aging, Neuropsychology, and Cognition, 12, 278). The present study examined the effects of concurrent interference tasks during the study or test phases of training to localize the source of gains. Overall, the results suggest that training is resilient and resistant to interference, but also that the processes used during the test phases of training are more important to the gains seen in the primary task and in the transfer tasks than those used in the study phases.

Representational momentum in older adults

Humans have a tendency to perceive motion even in static images that simply "imply" movement. This tendency is so strong that our memory for actions depicted in static images is distorted in the direction of implied motion - a phenomenon known as representational momentum (RM). In the present study, we created an RM display depicting a pattern of implied (clockwise) rotation of a rectangle. Young adults viewers' memory of the final position of the test rectangle was biased in the direction of continuing rotation, but older adults did not show a similar memory bias. We discuss several possible explanations for this group difference, but argue that the failure of older adults to shown an RM effect most likely reflects age-related changes in areas of the brain involved in processing real and implied motion.

Designing clinical trials for assessing the effects of cognitive training and physical activity interventions on cognitive outcomes: the Seniors Health and Activity Research Program Pilot (SHARP-P) study, a randomized controlled trial

Background

The efficacy of non-pharmacological intervention approaches such as physical activity, strength, and cognitive training for improving brain health has not been established. Before definitive trials are mounted, important design questions on participation/adherence, training and interventions effects must be answered to more fully inform a full-scale trial.

Methods

SHARP-P was a single-blinded randomized controlled pilot trial of a 4-month physical activity training intervention (PA) and/or cognitive training intervention (CT) in a 2 × 2 factorial design with a health education control condition in 73 community-dwelling persons, aged 70-85 years, who were at risk for cognitive decline but did not have mild cognitive impairment.

Results

Intervention attendance rates were higher in the CT and PACT groups: CT: 96%, PA: 76%, PACT: 90% (p=0.004), the interventions produced marked changes in cognitive and physical performance measures (p≤0.05), and retention rates exceeded 90%. There were no statistically significant differences in 4-month changes in composite scores of cognitive, executive, and episodic memory function among arms. Four-month improvements in the composite measure increased with age among participants assigned to physical activity training but decreased with age for other participants (intervention*age interaction p = 0.01). Depending on the choice of outcome, two-armed full-scale trials may require fewer than 1,000 participants (continuous outcome) or 2,000 participants (categorical outcome).

Conclusions

Good levels of participation, adherence, and retention appear to be achievable for participants through age 85 years. Care should be taken to ensure that an attention control condition does not attenuate intervention effects. Depending on the choice of outcome measures, the necessary sample sizes to conduct four-year trials appear to be feasible.

Trial Registration

Clinicaltrials.gov Identifier: NCT00688155

Telephone interview for cognitive status (TICS) screening for clinical trials of physical activity and cognitive training: the seniors health and activity research program pilot (SHARP-P) study

OBJECTIVE

To examine the performance of the Telephone Interview for Cognitive Status (TICS) for identifying participants appropriate for trials of physical activity and cognitive training interventions.

METHODS

Volunteers (N=343), ages 70-85 years, who were being recruited for a pilot clinical trial on approaches to prevent cognitive decline, were administered TICS and required to score ≥ 31 prior to an invitation to attend clinic-based assessments. The frequencies of contraindications for physical activity and cognitive training interventions were tallied for individuals grouped by TICS scores. Relationships between TICS scores and other measures of cognitive function were described by scatterplots and correlation coefficients.

RESULTS

Eligibility criteria to identify candidates who were appropriate candidates for the trial interventions excluded 51.7% of the volunteers with TICS<31. TICS scores above this range were not strongly related to cognition or attendance at screening visits, however overall enrollment yields were approximately half for participants with TICS=31 versus TICS=41, and increased in a graded fashion throughout the range of scores.

CONCLUSIONS

Use of TICS to define eligibility criteria in trials of physical activity and cognitive training interventions may not be worthwhile in that many individuals with low scores would already be eliminated by intervention-specific criteria and the relationship of TICS with clinic-based tests of cognitive function among appropriate candidates for these interventions may be weak. TICS may be most useful in these trials to identify candidates for oversampling in order to obtain a balanced cohort of participants at risk for cognitive decline.

Learning to diminish the effects of proactive interference: reducing false memory for young and older adults

Results from two experiments revealed that prior experience with proactive interference (PI) diminished PI's effects for both young and older adults. Participants were given two rounds of experience, with different materials, in a situation that produced PI. Comparisons with a control condition showed that the effects of PI on accuracy and on high-confidence intrusion errors (false memory) were reduced on the second round, as compared with those on the first. Also, the ability of confidence to diagnose accuracy of responding improved across rounds. Effects of prior experience with PI depended on feedback given at the time of test (Experiment 1). At least in part, the diminishment of PI resulted from participants' allocating more attention to interference items during study in the second round than in the first (Experiment 2). Implications of the results for interpreting age differences in PI and false memory are discussed.

Effects of self-paced encoding and practice on age-related deficits in binding three features

Although much literature suggests that the age-related decline in episodic memory could be due to difficulties in binding features of information, previous studies focused mainly on memory of paired associations rather than memory of multiple bound features. In reality, however, there are many situations that require binding multiple features together simultaneously. Thus, this three-part experimental study using a working memory task examined two fundamental questions: whether and how well older adults perform a working memory task that requires them to bind three features together (Experiment 1), and whether and how much older adults' memory of units of three bound features could be improved by self-paced encoding and 3 weeks practice (Experiments 2 & 3). The results indicated that although older adults performed as well as young adults in remembering one unit of three features, they showed a deficit in remembering two units, making more severe errors than young adults, and the difference between the two age groups increased when remembering three units. However, older adults improved their memory performance substantially by two means: self-paced encoding and practice. The former primarily shortened reaction times while the latter primarily improved memory accuracy. With self-paced encoding, older adults were also capable of binding at least three units during encoding. Thus, it is possible to assume that under an optimal encoding period, the age-related deficits occur probably not at encoding but at retention and/or retrieval.

Representational explanations of "process" dissociations in recognition: the DRYAD theory of aging and memory judgments

It is widely assumed that older adults suffer a deficit in the psychological processes that underlie remembering of contextual or source information. This conclusion is based in large part on empirical interactions, including disordinal ones, that reveal differential effects of manipulations of memory strength on recognition in young and old subjects. This article lays out an alternative theory that takes as a starting point the overwhelming evidence from the psychometric literature that the effects of age on memory share a single mediating influence. Thus, the theory assumes no differences between younger and older subjects other than a global difference in memory fidelity--that is, the older subjects are presumed to have less valid representations of events and objects than are young subjects. The theory is articulated through 3 major assumptions and implemented in a computational model, DRYAD, to simulate fundamental results in the literature on aging and recognition, including the very interactions taken to imply selective impairment in older people. The theoretical perspective presented here allows for a critical examination of the widely held belief that aging entails the selective disruption of particular memory processes.

A cognitive training intervention increases resting cerebral blood flow in healthy older adults

Healthy aging is typically accompanied by some decline in cognitive performance, as well as by alterations in brain structure and function. Here we report the results of a randomized, controlled trial designed to determine the effects of a novel cognitive training program on resting cerebral blood flow (CBF) and gray matter (GM) volume in healthy older adults. Sixty-six healthy older adults participated in 8 weeks of either a training program targeting attention and distractibility or an educational control program. This training program produced significantly larger increases in resting CBF to the prefrontal cortex than the control program. Increases in blood flow were associated with reduced susceptibility to distraction after training, but not with alterations in GM volume. These data demonstrate that cognitive training can improve resting CBF in healthy older adults and that cerebral perfusion rates may be a more sensitive indicator of the benefits of cognitive training than volumetric analyses.

Effects of immediate feedback and errorless learning on recognition memory processing in young and older adults

Age-related memory decline appears to be due to impaired recollection whereas familiarity may be intact. An intervention was therefore designed with the aim of optimising use of this intact sense of familiarity. A continuous face recognition paradigm was used which required detection of repeats in a long series. The experimental intervention consisted of immediate feedback on response accuracy and avoidance of errors by discouraging guessing. Experimental and control interventions were compared by recruiting 40 people aged under 30 years or over 60 years for six 45-minute training sessions. The elderly participants initially showed a more lax response criterion than young people but the experimental intervention reversed this effect so that by the end of training the elderly participants were less prone to false alarms than the younger participants. However, there was only limited evidence of generalisation of this training effect to other memory tasks and no effect on recognition sensitivity. This study demonstrates that combined feedback and errorless learning allow elderly people to adjust their response criterion during recognition memory tasks. Taken together with previous encouraging studies, it seems that this training approach might have potential as a therapy for age-related memory impairment. However this would require development of additional methods to enhance generalisation beyond trained tasks and to elicit improvements in sensitivity as well as reduction of false alarms. The separate contributions of feedback and errorless learning also need to be investigated.

How useful is executive control training? Age differences in near and far transfer of task-switching training

Although executive functions can be improved by training, little is known about the extent to which these training-related benefits can be transferred to other tasks, or whether this transfer can be modulated by the type of training. This study investigated lifespan changes in near transfer of task-switching training to structurally similar tasks and its modulation by verbal self-instructions and variable training, as well as far transfer to structurally dissimilar 'executive' tasks and fluid intelligence. Three age groups (8-10; 18-26; 62-76 years of age) were examined in a pretest-training-posttest design. We found near transfer of task-switching training in all age groups, especially in children and older adults. Near transfer was enhanced in adults and impaired in children when training tasks were variable. We also found substantial far transfer to other executive tasks and fluid intelligence in all age groups, pointing to the transfer of relatively general executive control abilities after training.