Can cognitive training improve episodic memory?

Home-Based Cognitive Intervention for Healthy Older Adults Through Asking Robots Questions: Randomized Controlled Trial

Background

Asking questions is common in conversations, and while asking questions, we need to listen carefully to what others say and consider the perspective our questions adopt. However, difficulties persist in verifying the effect of asking questions on older adults' cognitive function due to the lack of a standardized system for conducting experiments at participants' homes.

Objective

This study examined the intervention effect of cognitive training moderated by robots on healthy older adults. A focus on the feasibility of the intervention at participants' homes was also maintained. Feasibility was evaluated by considering both the dropout rate during the intervention and the number of questions posed to each participant during the experiment.

Methods

We conducted a randomized controlled trial with 81 adults older than 65 years. Participants were recruited through postal invitations and then randomized into 2 groups. The intervention group (n=40) received sessions where participants listened to photo-integrated stories and posed questions to the robots. The control group (n=41) received sessions where participants listened to photo-integrated stories and only thanked the robots for confirming participation. The participants participated in 12 dialogue sessions for 2-3 weeks. Scores of global cognitive functioning tests, recall tests, and verbal fluency tasks measured before and after the intervention were compared between the 2 groups.

Results

There was no significant intervention effect on the Telephone Interview for Cognitive Status-Japanese scores, recall tests, and verbal fluency tasks. Additionally, our study successfully concluded with no participant dropouts at follow-up, confirming the feasibility of our approach.

Conclusions

There was no statistically significant evidence indicating intervention benefits for cognitive functioning. Although the feasibility of home-based interventions was demonstrated, we identified areas for improvement in the future, such as setting up more efficient session themes. Further research is required to identify the effectiveness of an improved cognitive intervention involving the act of asking questions.

Cognitive Training with Neurofeedback Using fNIRS Improves Cognitive Function in Older Adults

This study examined the effects of a 4-week cognitive training program with neurofeedback (CT-NF) among 86 healthy adults (M = 66.34 years, range 54-84) randomized to either a treatment (app-based ABC games) or control (Tetris) group. Participants completed seven cognitive assessments, pre- and post-intervention, and measured their cortical brain activity using a XB-01 functional near-infrared spectroscopy (fNIRS) brain sensor, while engaging in CT-NF. The treatment (ABC) group showed significant (pre/post-intervention) improvements in memory (MEM), verbal memory (VBM), and composite cognitive function, while the control group did not. However, both groups showed significant improvements in processing speed (PS) and executive function (EF). In line with other studies, we found that strength of cortical brain activity (measured during CT-NF) was associated with both cognitive (pre and post) and game performance. In sum, our findings suggest that CT-NF and specifically ABC exercises, confer improved cognition in the domains of MEM, VBM, PS, and EF.

Engagement in Cognitively Stimulating Activities Mediates the Relationship between Openness and Attention/Executive Functions, but Not Memory in Older Adults

OBJECTIVE

Openness has a positive association with cognitive functioning and engagement in cognitively stimulating activities (CSA). Older adults who engage in more CSA tend to show greater preservation of their cognitive skills; thus, we examined whether: higher Openness would be associated with higher attention/executive functions (AEF) and verbal memory; and CSA would mediate the relationship between Openness and AEF, as well as verbal memory.

METHOD

477 community-dwelling older adults (65+ years) were included in the current cross-sectional study. Composite variables of AEF (TMT-A&B, COWAT, and DSST) and verbal memory (RBANS immediate and delayed verbal memory subtasks) were included. Openness was assessed via the Big-5 Inventory and CSA with the Leisure Activity Questionnaire.

METHOD

477 community-dwelling older adults (65+ years) were included in the current cross-sectional study. Composite variables of AEF (TMT-A&B, COWAT, and DSST) and verbal memory (RBANS verbal memory subtasks) were included. Openness was assessed via the Big-5 Inventory and CSA with the Leisure Activity Questionnaire.

RESULTS

Linear regressions indicated a significant positive association between Openness and AEF (β = .09, p < .01), but not verbal memory (β = .06, p = .06). A significant partial mediation was demonstrated between Openness, CSA, and AEF (c: β = .08, p < .05, 95%CI = .02-.14; c': β = .02, 95%CI = .01-.03). The mediation of Openness, CSA, and verbal memory was not significant (c: β = .06, p > .05, 95%CI = .01-.11; c': β = .00, 95%CI = -.01-.01).

CONCLUSIONS

The association between Openness and AEF, but not verbal memory, was partially mediated by CSA in healthy older adults. The findings suggest that those who are more open to and highly engaged in CSA may have a later in life advantage in preserving their AEF abilities.

A meta-analysis of memory ability in synaesthesia

People with synaesthesia (e.g., experiencing colours for letters and numbers) have been reported to possess enhanced memory relative to the general population. However, there are also inconsistencies in this literature and it is unclear whether this reflects sampling error (exacerbated by low Ns) or more meaningful differences that arise because synaesthesia relates to some aspects of memory more than others. To this end, a multi-level meta-analysis was conducted. Synaesthetes have enhanced long-term (episodic) memory with a medium population effect size ( dˆ  = 0.61), whereas the effects on working memory (short-term memory) were significantly smaller ( dˆ  = 0.36) but still exceeded that of controls. Moderation analyses suggested that, aside from the division between long-term vs. working memory, the effects of synaesthesia are pervasive, i.e., they extend to all kinds of stimuli, and extend to all kinds of test formats. This pattern is hard to reconcile with the view that synaesthetic experiences directly support memory ability: for instance, digit span (where synaesthesia could be helpful) showed a small effect whereas episodic memory for abstract images (where synaesthesia is irrelevant) yielded larger effects. Synaesthesia occupies a unique position of being the only known neurodevelopmental condition linked to a pervasive enhancement of long-term memory.

Working Memory Capacity as a Predictor of Cognitive Training Efficacy in the Elderly Population

Aging is associated with a decline in a wide range of cognitive functions and working memory (WM) deterioration is considered a main factor contributing to this. Therefore, any attempt to counteract WM decline seems to have a potential benefit for older adults. However, determination of whether such methods like WM trainings are effective is a subject of a serious debate in the literature. Despite a substantial number of training studies and several meta-analyses, there is no agreement on the matter of their effectiveness. The other important and still not fully explored issue is the impact of the preexisting level of intellectual functioning on the training's outcome. In our study we investigated the impact of WM training on variety of cognitive tasks performance among older adults and the impact of the initial WM capacity (WMC) on the training efficiency. 85 healthy older adults (55-81 years of age; 55 female, 30 males) received 5 weeks of training on adaptive dual N-back task (experimental group) or memory quiz (active controls). Cognitive performance was assessed before and after intervention with measures of WM, memory updating, inhibition, attention shifting, short-term memory (STM) and reasoning. We found post-intervention group independent improvements across all cognitive tests except for inhibition and STM. With multi-level analysis individual learning curves were modeled, which enabled examining of the intra-individual change in training and inter-individual differences in intra-individual changes. We observed a systematic and positive, but relatively small, learning trend with time. Moderator analyses with demographic characteristics as moderators showed no additional effects on learning curves. Only initial WMC level was a significant moderator of training effectiveness. Older adults with initially lower WMC improved less and reached lower levels of performance, compared to the group with higher WMC. Overall, our findings are in accordance with the research suggesting that post-training gains are within reach of older adults. Our data provide evidence supporting the presence of transfer after N-back training in older adults. More importantly, our findings suggest that it is more important to take into account an initial WMC level, rather than demographic characteristics when evaluating WM training in older adults.

Adaptive task difficulty influences neural plasticity and transfer of training

The efficacy of cognitive training is controversial, and research progress in the field requires an understanding of factors that promote transfer of training gains and their relationship to changes in brain activity. One such factor may be adaptive task difficulty, as adaptivity is predicted to facilitate more efficient processing by creating a prolonged mismatch between the supply of, and the demand upon, neural resources. To test this hypothesis, we measured behavioral and neural plasticity in fMRI sessions before and after 10 sessions of working memory updating (WMU) training, in which the difficulty of practiced tasks either adaptively increased in response to performance or was fixed. Adaptive training resulted in transfer to an untrained episodic memory task and activation decreases in striatum and hippocampus on a trained WMU task, and the amount of training task improvement was associated with near transfer to other WMU tasks and with hippocampal activation changes on both near and far transfer tasks. These findings suggest that cognitive training programs should incorporate adaptive task difficulty to broaden transfer of training gains and maximize efficiency of task-related brain activity.

Factors Explaining Language Performance After Training in Elders With and Without Subjective Cognitive Decline

The present study explores if cognitive reserve, executive functions, and working memory capacity are predictive of performance in the language domain (specifically in sentence comprehension and naming) after a cognitive training intervention. Sixty-six Spanish older adults voluntarily participated in the study, classified either as older adults with subjective cognitive decline according to Jessen et al.’s (2014) criteria (n = 35; 70.94 ± 4.16 years old) or cognitively intact (n = 31; 71.34 ± 4.96 years old). Written sentence comprehension and visual confrontation naming were assessed both immediately after recruitment (at the baseline), and then 6 months later, once each participant had completed his/her cognitive training (a well-known program in Spain, called UMAM; English translation: Madrid City Council Memory Unit Program). Cognitive reserve, executive functions (cognitive flexibility and controlled interference efficiency), and working memory capacity were measured for all participants at the baseline. Results pointed out that the subjective cognitive decline group presented greater benefits in the language domain than cognitively intact participants. We also observed that lower executive functioning and working memory capacity at the baseline predicted larger benefits in language performance after training, but only in the group of cognitively intact older adults. However, selected predictors hardly explained subjective cognitive decline participants’ results in language performance after training.

Efficacy of Cognitive Training in Older Adults with and without Subjective Cognitive Decline Is Associated with Inhibition Efficiency and Working Memory Span, Not with Cognitive Reserve

The present study explores the role of cognitive reserve, executive functions, and working memory (WM) span, as factors that might explain training outcomes in cognitive status. Eighty-one older adults voluntarily participated in the study, classified either as older adults with subjective cognitive decline or cognitively intact. Each participant underwent a neuropsychological assessment that was conducted both at baseline (entailing cognitive reserve, executive functions, WM span and depressive symptomatology measures, as well as the Mini-Mental State Exam regarding initial cognitive status), and then 6 months later, once each participant had completed the training program (Mini-Mental State Exam at the endpoint). With respect to cognitive status the training program was most beneficial for subjective cognitive decline participants with low efficiency in inhibition at baseline (explaining a 33% of Mini-Mental State Exam total variance), whereas for cognitively intact participants training gains were observed for those who presented lower WM span.

Prospective and retrospective memory are differentially related to self-rated omission and commission errors in medication adherence in multimorbidity

We investigated the relations of self-rated omission errors (i.e., forgetting to take one's medication) and commission errors (i.e., unnecessary repetitions of medication intake because of forgetting that it has already been taken) in medication adherence in multimorbidity to prospective and retrospective memory performance. Moreover, we examined whether these relations were moderated by the number of medications that had to be taken. Eighty-four patients with multimorbidity (aged 28-84 years, M = 62.4) reported medication adherence regarding the last seven days and the number of medications they had to take. In addition, we administered psychometric tests on prospective memory (PM) and retrospective memory performance. We found that reported omission errors in medication adherence were related significantly to lower PM performance. This relationship was increased in individuals with a lower number of medications. In comparison, reported commission errors in medication adherence were related significantly to lower retrospective memory performance. This relationship was increased in individuals with a larger number of medications. Present data suggest that omission errors in medication adherence in multimorbidity may reflect primarily PM errors, particularly if few medications have to be taken, while commission errors may reflect mainly retrospective memory failures, especially with a large number of medications that need to be taken as prescribed. From an applied neuropsychological perspective, these results underline the importance of trying to enhance PM and retrospective memory performance in patients with multimorbidity.

Mindfulness Enhances Episodic Memory Performance: Evidence from a Multimethod Investigation

Training in mindfulness, classically described as a receptive attentiveness to present events and experiences, has been shown to improve attention and working memory. Both are key to long-term memory formation, and the present three-study series used multiple methods to examine whether mindfulness would enhance episodic memory, a key form of long-term memory. In Study 1 (N = 143), a self-reported state of mindful attention predicted better recognition performance in the Remember-Know (R-K) paradigm. In Study 2 (N = 93), very brief training in a focused attention form of mindfulness also produced better recognition memory performance on the R-K task relative to a randomized, well-matched active control condition. Study 3 (N = 57) extended these findings by showing that relative to randomized active and inactive control conditions the effect of very brief mindfulness training generalized to free-recall memory performance. This study also found evidence for mediation of the mindfulness training—episodic memory relation by intrinsic motivation. These findings indicate that mindful attention can beneficially impact motivation and episodic memory, with potential implications for educational and occupational performance.

Task-based neurofeedback training: A novel approach toward training executive functions

Cognitive training is an emergent approach to improve cognitive functions in various neurodevelopmental and neurodegenerative diseases. However, current training programs can be relatively lengthy, making adherence potentially difficult for patients with cognitive difficulties. Previous studies suggest that providing individuals with real-time feedback about the level of brain activity (neurofeedback) can potentially help them learn to control the activation of specific brain regions. In the present study, we developed a novel task-based neurofeedback training paradigm that benefits from the effects of neurofeedback in parallel with computerized training. We focused on executive function training given its core involvement in various developmental and neurodegenerative diseases. Near-infrared spectroscopy (NIRS) was employed for providing neurofeedback by measuring changes in oxygenated hemoglobin in the prefrontal cortex. Of the twenty healthy adult participants, ten received real neurofeedback (NFB) on prefrontal activity during cognitive training, and ten were presented with sham feedback (SHAM). Compared with SHAM, the NFB group showed significantly improved executive function performance including measures of working memory after four sessions of training (100min total). The NFB group also showed significantly reduced training-related brain activity in the executive function network including right middle frontal and inferior frontal regions compared with SHAM. Our data suggest that providing neurofeedback along with cognitive training can enhance executive function after a relatively short period of training. Similar designs could potentially be used for patient populations with known neuropathology, potentially helping them to boost/recover the activity in the affected brain regions.

Computerized and virtual reality cognitive training for individuals at high risk of cognitive decline: systematic review of the literature

The aim of this study was to assess the efficacy of cognitive training, specifically computerized cognitive training (CCT) and virtual reality cognitive training (VRCT), programs for individuals living with mild cognitive impairment (MCI) or dementia and therefore at high risk of cognitive decline. After searching a range of academic databases (CINHAL, PSYCinfo, and Web of Science), the studies evaluated (N = 16) were categorized as CCT (N = 10), VRCT (N = 3), and multimodal interventions (N = 3). Effect sizes were calculated, but a meta-analysis was not possible because of the large variability of study design and outcome measures adopted. The cognitive domains of attention, executive function, and memory (visual and verbal) showed the most consistent improvements. The positive effects on psychological outcomes (N = 6) were significant reductions on depressive symptoms (N = 3) and anxiety (N = 2) and improved perceived use of memory strategy (N = 1). Assessments of activities of daily living demonstrated no significant improvements (N = 8). Follow-up studies (N = 5) demonstrated long-term improvements in cognitive and psychological outcomes (N = 3), and the intervention groups showed a plateau effect of cognitive functioning compared with the cognitive decline experienced by control groups (N = 2). CCT and VRCT were moderately effective in long-term improvement of cognition for those at high risk of cognitive decline. Total intervention time did not mediate efficacy. Future research needs to improve study design by including larger samples, longitudinal designs, and a greater range of outcome measures, including functional and quality of life measures, to assess the wider effect of cognitive training on individuals at high risk of cognitive decline.

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.

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.

The Contribution of Executive Function to Source Memory Development in Early Childhood

Age-related differences in episodic memory judgments assessing recall of fact information and the source of this information were examined. The role of executive function in supporting early episodic memory ability was also explored. Four- and 6-year-old children were taught 10 novel facts from two different sources (experimenter or puppet) and memory for both fact and source information was later tested. Measures of working memory, inhibitory control, and set-shifting were obtained to produce an indicator of children's executive function. Six-year-olds recalled more fact and source information than 4-year-olds. Regression analyses revealed that age, language ability, and executive function accounted for unique variance in children's fact recall and source recall performance. These findings suggest a link between episodic memory and executive function, and we propose that developmental investigations should further explore this association.

A potential spatial working memory training task to improve both episodic memory and fluid intelligence

One current challenge in cognitive training is to create a training regime that benefits multiple cognitive domains, including episodic memory, without relying on a large battery of tasks, which can be time-consuming and difficult to learn. By giving careful consideration to the neural correlates underlying episodic and working memory, we devised a computerized working memory training task in which neurologically healthy participants were required to monitor and detect repetitions in two streams of spatial information (spatial location and scene identity) presented simultaneously (i.e. a dual n-back paradigm). Participants' episodic memory abilities were assessed before and after training using two object and scene recognition memory tasks incorporating memory confidence judgments. Furthermore, to determine the generalizability of the effects of training, we also assessed fluid intelligence using a matrix reasoning task. By examining the difference between pre- and post-training performance (i.e. gain scores), we found that the trainers, compared to non-trainers, exhibited a significant improvement in fluid intelligence after 20 days. Interestingly, pre-training fluid intelligence performance, but not training task improvement, was a significant predictor of post-training fluid intelligence improvement, with lower pre-training fluid intelligence associated with greater post-training gain. Crucially, trainers who improved the most on the training task also showed an improvement in recognition memory as captured by d-prime scores and estimates of recollection and familiarity memory. Training task improvement was a significant predictor of gains in recognition and familiarity memory performance, with greater training improvement leading to more marked gains. In contrast, lower pre-training recollection memory scores, and not training task improvement, led to greater recollection memory performance after training. Our findings demonstrate that practice on a single working memory task can potentially improve aspects of both episodic memory and fluid intelligence, and that an extensive training regime with multiple tasks may not be necessary.