Making working memory work: a meta-analysis of executive-control and working memory training in older adults

Locating neural transfer effects of n-back training on the central executive: a longitudinal fMRI study

The large number of behavioral studies testing whether working memory training improves performance on an untrained task have yielded inconclusive results. Moreover, some studies have investigated the possible neural changes during the performance of untrained tasks after training. Here, we studied the transfer from n-back training to the Paced Auditory Serial Addition Test (PASAT), two different tasks that use the central executive system to maintain verbal stimuli. Participants completed fMRI sessions at baseline, immediately after one week of training, and at the five-week follow-up. Although behavioral transfer effects were not obtained, training was associated with decreased activation in the anterior dorsolateral prefrontal cortex (DLPFC; BA 9/46) while performing the PASAT that remained stable five weeks later. Consistent with our hypothesis, the changes in the anterior DLFPC largely overlapped with the n-back task fMRI activations. In conclusion, working memory training improves efficiency in brain areas involved in the trained task that may affect untrained tasks, specifically in brain areas responsible for the same cognitive processes.

From Evaluation to Prediction: Behavioral Effects and Biological Markers of Cognitive Control Intervention

Although the intervention effectiveness of cognitive control is disputed, some methods, such as single-task training, integrated training, meditation, aerobic exercise, and transcranial stimulation, have been reported to improve cognitive control. This review of recent advances from evaluation to prediction of cognitive control interventions suggests that brain modularity may be an important candidate marker for informing clinical decisions regarding suitable interventions. The intervention effect of cognitive control has been evaluated by behavioral performance, transfer effect, brain structure and function, and brain networks. Brain modularity can predict the benefits of cognitive control interventions based on individual differences and is independent of intervention method, group, age, initial cognitive ability, and education level. The prediction of cognitive control intervention based on brain modularity should extend to task states, combine function and structure networks, and assign different weights to subnetwork modularity.

Acute increases in brain-derived neurotrophic factor in plasma following physical exercise relates to subsequent learning in older adults

Multidomain lifestyle interventions represents a promising strategy to counteract cognitive decline in older age. Brain-derived neurotrophic factor (BDNF) is essential for experience-dependent plasticity and increases following physical exercise, suggesting that physical exercise may facilitate subsequent learning. In a randomized-controlled trial, healthy older adults (65–75 years) completed a 12-week behavioral intervention that involved either physical exercise immediately before cognitive training (n = 25; 13 females), physical exercise immediately after cognitive training (n = 24; 11 females), physical exercise only (n = 27; 15 females), or cognitive training only (n = 21; 12 females). We hypothesized that cognition would benefit more from cognitive training when preceded as opposed to followed by physical exercise and that the relationship between exercise-induced increases in peripheral BDNF and cognitive training outcome would be greater when cognitive training is preceded by physical exercise. Greater increases of plasma BDNF were associated with greater cognitive training gains on trained task paradigms, but only when such increases preceded cognitive training (ß = 0.14, 95% CI [0.04, 0.25]). Average cognitive training outcome did not differ depending on intervention order (ß = 0.05, 95% CI [−0.10, 0.20]). The study provides the first empirical support for a time-critical but advantageous role for post-exercise increases in peripheral BDNF for learning at an interindividual level in older adults, with implications for future multidomain lifestyle interventions.

Neurophysiological indices of the transfer of cognitive training gains to untrained tasks

Targeted training of working memory (WM) may improve performance and modulate brain function in untrained cognitive modalities. Demanding cognitive training protocols that do not target WM may also improve performance on untrained cognitive tests, but the delineation between transfer effects that are unique to WM training and effects that are shared among different cognitive training modalities has not been well-established. To address this, we examined the effects of twenty sessions of either WM training (visual n-back task with letter stimuli) or selective attention training (visual search task with letter array stimuli) on brain function during untrained WM and cognitive control tasks. Event-related potentials (ERPs) were obtained at baseline (pretest) and after the training period (posttest) for two untrained tasks - a Spatial 3-back task measuring spatial WM, and a Go/NoGo Flanker task measuring cognitive control. The n-back training group had more pronounced pretest-to-posttest performance improvements on the Spatial 3-back task compared to the search training group. N-back training was also associated with pretest-to-posttest enhancement of N1 amplitude and reduced N2 latency on trials of the task in which where there was a stimulus match, as well as enhancement of a late positive potential (550-750 msec post-stimulus) for all trials of the task. These ERP effects suggest that n-back training resulted in enhancement of attention to spatial locations, earlier onset of conflict monitoring processes, and changes in the engagement of neural activity during the retention interval, respectively. Both groups had faster reaction time on Go trials of the Go/NoGo Flanker task at posttest compared to pretest. Relatively subtle training-related effects were observed for N2 amplitude on this task, in line with the notion that training (particularly n-back training) was associated with improved conflict monitoring. Further, search training resulted in earlier onset of P2 and P3 latency at posttest compared to pretest. Taken together, the ERP findings for both tasks identify specific cognitive processes that are associated with transfer to untrained tasks after distinct forms of cognitive training.

Uncovering Susceptibility Risk to Online Deception in Aging

OBJECTIVES

Fraud in the aged is an emerging public health problem. An increasingly common form of deception is conducted online. However, identification of cognitive and socioemotional risk factors has not been undertaken yet. In this endeavor, this study extended previous work suggesting age effects on susceptibility to online deception.

METHODS

Susceptibility was operationalized as clicking on the link in simulated spear-phishing emails that young (18-37 years), young-old (62-74 years), and middle-old (75-89 years) Internet users received, without knowing that the emails were part of the study. Participants also indicated for a set of spear-phishing emails how likely they would click on the embedded link (susceptibility awareness) and completed cognitive and socioemotional measures to determine susceptibility risk profiles.

RESULTS

Higher susceptibility was associated with lower short-term episodic memory in middle-old users and with lower positive affect in young-old and middle-old users. Greater susceptibility awareness was associated with better verbal fluency in middle-old users and with greater positive affect in young and middle-old users.

DISCUSSION

Short-term memory, verbal fluency, and positive affect in middle-old age may contribute to resilience against online spear-phishing attacks. These results inform mechanisms of online fraud susceptibility and real-life decision-supportive interventions toward fraud risk reduction in aging.

The Role of Executive Functions in Socioeconomic Attainment Gaps: Results From a Randomized Controlled Trial

The socioeconomic attainment gap in mathematics starts early and increases over time. This study aimed to examine why this gap exists. Four-year-olds from diverse backgrounds were randomly allocated to a brief intervention designed to improve executive functions (N = 87) or to an active control group (N = 88). The study was preregistered and followed CONSORT guidelines. Executive functions and mathematical skills were measured at baseline, 1 week, 3 months, 6 months, and 1 year posttraining. Executive functions mediated the relation between socioeconomic status and mathematical skills. Children improved over training, but this did not transfer to untrained executive functions or mathematics. Executive functions may explain socioeconomic attainment gaps, but cognitive training directly targeting executive functions is not an effective way to narrow this gap.

Differential effects of cognitive training modules in healthy aging and mild cognitive impairment: A comprehensive meta-analysis of randomized controlled trials

This meta-analysis was designed to compare the effectiveness of 2 cognitive training modules, single-component training, which targets 1 specific cognitive ability, versus multicomponent training, which trains multiple cognitive abilities, on both trained abilities (near transfer) and untrained abilities (far transfer) in older adults. The meta-analysis also assessed whether individual differences in mental status interacted with the extent of transfer. Eligible randomized controlled trials (215 training studies) examined the immediate effects of cognitive training in either healthy aging (HA) or mild cognitive impairment (MCI). Results yielded an overall net-gain effect size (g) for the cognitive training of 0.28 (p < .001). These effects were similar across mental status and training modules, and were significant for both near (g = 0.37) and far (g = 0.22) transfer. Although all training modules yielded significant near transfer, only a few yielded significant far transfer. Single-component training of executive functions was most effective on near and far transfer, with processing speed training improving everyday functioning. All modules of multicomponent training (specific and nonspecific) yielded significant near and far transfer, including everyday functioning. Training effects on cognition were moderated by educational attainment and number of cognitive outcomes, but only in HA. These findings suggest that, in older adults, all modules of multicomponent training are more effective in engendering near and far transfer, including everyday functioning, when compared with single-component training modules. (PsycINFO Database Record (c) 2020 APA, all rights reserved).

Higher-order processing and change-to-automaticity as explanations of the item-position effect in reasoning tests

Higher-order processing and learning are two alternative explanations of the item-position effect. Whereas higher-order processing as explanation emphasizes the recruitment of executive processes, learning as explanation highlights the improvement in performance due to repetition and is specified as change-to-automaticity. In a sample of 287 participants the item-position effect was captured by means of Advanced Progressive Matrices. Higher-order processing was inferred from rule acquisition, and change-to-automaticity was derived from sustained attention data. The results of independent investigations revealed that both higher-order processing and change-to-automaticity contributed to the occurrence of the item-position effect.

Home-based evaluation of executive function (Home-MET) for older adults with mild cognitive impairment

INTRODUCTION

Executive function helps older adults maintain their activities of daily living by making plans, setting goals, and carrying them out successfully. It is important for their independence in community living.

METHODS

With a carefully match-group of 80 mild cognitive impaired with 80 health control subjects. The home-based evaluation of executive function (Home-MET) was validated in subjects' own living environment.

RESULTS

This Home-MET showed significant correlation in the assessment of attention control that was assessing by Test of Everyday Attention (TEA) (r = .86, p < .01), with working memory that was assessed with Trail Making Test (TMT) (r = .72, p < .01), with inhibitory control that was assessing with Stroop Test (r = .86, p < .01), with individuals' functional disability was assessed by Chinese Disability Assessment of Dementia (CDAD) (r = .77, p < .01) and cognitive assessment was assessed by Hong Kong Montreal Cognitive Assessment (HK-MoCA) (r = .88, p < .01). By benchmarking with the validated performance-based executive function assessment, the Home-MET shows significant correlation (r = .92, p < .05) with the executive function test in a standard environment in hospital, i.e. the Chinese Multiple Errands Test (the Chinese-MET). The two-stage hierarchical linear regression model with backward method showed functional disability was a marginally significant predictor (p < .059) for the Home-MET with regression model showed with R² = .93.

CONCLUSION

Results indicated the Home-MET, can provide an objective measure of executive function for subjects with mild cognitive impairment in participants' own home environment.

Effects of Home-Based Working Memory Training on Visuo-Spatial Working Memory in Parkinson's Disease: A Randomized Controlled Trial

BACKGROUND

Cognitive impairment is a very frequent and severe nonmotor symptom of Parkinson's disease (PD). Early intervention in this at-risk group for cognitive decline may be crucial for long-term preservation of cognitive functions. Computerized working memory training (WMT) has been proven beneficial in non-PD patient populations, but such evidence is still needed for patients with PD.

OBJECTIVE

This study aimed to evaluate the effect of WMT on visuo-spatial working memory (WM) in cognitively unimpaired patients with PD.

METHODS

A single-blind randomized controlled trial encompassing 76 patients with PD but no cognitive impairment according to level II diagnostic criteria was conducted. Thirty-seven patients engaged in home-based adaptive WMT 5 times per week for a period of 5 weeks, whereas the remaining patients were in the waiting list arm of the study (control group [CG]). Working memory performance was evaluated using a computerized task before and after intervention and at 14-week follow-up, allowing to quantify the precision of WM on a continuous scale, ie, to test not only if an item was remembered but also how well the location of this item was retained.

RESULTS

Coincidently, the WMT group showed slightly worse WM performance compared with the CG at baseline, which was ameliorated after WMT. This training-induced effect remained stable until follow-up.

CONCLUSION

Patients showing relatively low WM performance, despite not formally diagnosable as Parkinson's disease with mild cognitive impairment (PD-MCI), seem to benefit from home-based WMT. Thus, WMT could potentially be implemented in future trials as a time- and cost-efficient route to counteract subtle cognitive changes in early disease stages.

TRIAL REGISTRATION

German Clinical Trial Register (drks.de, DRKS00009379).

Verbal working memory training in older adults: an investigation of dose response

The WM training protocol proposed by Borella et al. found specific and transfer effects among seniors, however, the studies were carried out in the same socio-cultural context and variations in the procedure were never tested. The present study aimed at analyzing the efficacy of Borella et al.'s training, in terms of short and long-term benefits, in a different socio-cultural context (Study 1), and the effect of change in the training's length (duplicating the number of sessions (Study 2). Participants were randomly assigned to a trained group (N = 18 for Study 1, and N = 23 for Study 2) and active control group (N = 28 for Study 1, and N = 27 for Study 2), and evaluated at pre, post-test and six-month follow-up for verbal WM task (criterion task), and for visuospatial and verbal WM, inhibition, processing speed, executive function, and fluid intelligence measures (transfer tasks). The trained groups had higher performance in all tasks when compared with active control groups after training and at 6 month follow-up. The longer training (Study 2) generated similar gains as the original protocol, with some advantage in far transfer tasks at post-test and follow-up. Study limitations include the small sample sizes. In conclusion, this training was effective in a different socio-cultural context and adding three sessions to the protocol did not significantly change training impact.

Disentangling the far transfer of language comprehension gains using latent mediation models

While we know that interventions targeting oral language can be effective, little is known about what drives these effects. In this study, we examine whether gains in transfer measures are mediated through the specific words that are trained in a language intervention. Based on a large-scale randomized controlled trial of language intervention in 4- to 5-year-old children, latent mediation models were used to disentangle oral language gains in transfer measures. The results first showed that the effects of the language intervention and the transfer effects are generated through expressive rather than receptive measures of language. Second, we found that the effects of the intervention on intermediate transfer measures of language were mediated through the ability to define the trained words. Third, and critically, for far transfer measures that did not contain any of the trained words, the effects were mediated through the trained words. The findings relate to theories of transfer and support the idea that far transfer is possible, at least within the same domain. In addition, it seems that effects on receptive language skills are difficult to obtain and that what is improved is instead the children's ability to express themselves and use procedures to explain words. Thus, to optimize intervention effects, future studies should focus on expressive language.

Plasticity in brain activity dynamics after task-shifting training in older adults

Cognitive control is supported by a dynamic interplay of transient (i.e., trial-related) brain activation across fronto-parietal networks and sustained (i.e., block-related) activation across fronto-striatal networks. Older adults show disturbances in this dynamic functional recruitment. There is evidence suggesting that cognitive-control training may enable older adults to redistribute their brain activation across cortical and subcortical networks, which in turn can limit behavioral impairments. However, previous studies have only focused on spatial rather than on temporal aspects of changes in brain activation. In the present study, we examined training-related functional plasticity in old age by applying a hybrid fMRI design that sensitively tracks the spatio-temporal interactions underlying brain-activation changes. Fifty healthy seniors were assigned to a task-shifting training or an active-control group and their pretest/posttest activation-change maps were compared against 25 untrained younger adults. After training, older adults showed the same performance as untrained young adults. Compared to the control group, task-shifting training promoted proactive (i.e., early, cue-related) changes in transient mechanisms supporting the maintenance and top-down biasing of task-set representations in a specific prefrontal circuitry; reactive (i.e., late, probe-related) changes in transient mechanisms supporting response-selection processes in dissociable fronto-parietal networks; overall reductions of sustained activation in striatal circuits. Results highlight the importance of spatio-temporal interactions in training-induced neural changes in age.

Effects of virtual reality-based cognitive training in older adults living without and with mild dementia: a pretest-posttest design pilot study

OBJECTIVE

Modern technologies are increasingly used in the development of cognitive interventions for older adults. Research into possible applications of virtual reality in such interventions has begun only recently. The aim of present study was to evaluate the effects of 8 sessions of VR-based cognitive training using the GRADYS game in healthy older adults (n = 72; aged 60-88) and older adults living with mild dementia (n = 27; aged 60-89).

RESULTS

Older adults with mild dementia demonstrated worse baseline cognitive performance than participants without dementia. Both groups showed progress in training, which was greater in healthy older adults. There were also significant differences in cognitive functioning before and after the training. However, positive changes were revealed almost exclusively in the group of older adults without dementia. Based on the findings, we can recommend the GRADYS game for cognitive enhancement and as a possible counter-measure for cognitive decline experienced in normal cognitive ageing. Our results provide also support for the usefulness of VR technology in cognitive interventions in older adults. The use of the GRADYS game in persons living with dementia, however, would require several of the hardware and software modifications. Trial registration ISRCTN17613444, date of registration: 10.09.2019. Retrospectively registered.

Spatio-Temporal Neural Changes After Task-Switching Training in Old Age

In the present study, we aimed at examining selective neural changes after task-switching training in old age by not only considering the spatial location but also the timescale of brain activation changes (i.e., sustained/block-related or transient/trial-related timescales). We assigned a sample of 50 older adults to a task-switching training or an active single-task control group. We administered two task paradigms, either sensitive to transient (i.e., a context-updating task) or sustained (i.e., a delayed-recognition working-memory task) dynamics of cognitive control. These dynamics were captured by utilizing an appropriate event-related or block-related functional magnetic resonance imaging design. We captured selective changes in task activation during the untrained tasks after task-switching training compared to an active control group. Results revealed changes at the neural level that were not evident from only behavioral data. Importantly, neural changes in the transient-sensitive context updating task were found on the same timescale but in a different region (i.e., in the left inferior parietal lobule) than in the task-switching training task (i.e., ventrolateral PFC, inferior frontal junction, superior parietal lobule), only pointing to temporal overlap, while neural changes in the sustained-sensitive delayed-recognition task overlapped in both timescale and region with the task-switching training task (i.e., in the basal ganglia), pointing to spatio-temporal overlap. These results suggest that neural changes after task-switching training seem to be critically supported by the temporal organization of neural processing.

Working Memory Training for Older Adults After Major Surgery: Benefits to Cognitive and Emotional Functioning

OBJECTIVES

Cognitive and mood changes can affect postoperative recovery in hospitalized older adults undergoing major surgical procedures, but few studies have considered postoperative cognitive interventions to sustain such patients' cognitive functioning and mood. The aim of this pilot study was to assess the efficacy of working memory training in improving cognitive functioning and mood, or emotional functioning, in older adults undergoing major surgery.

METHODS

Thirty-four older adults (from 64 to 75 years of age) hospitalized for partial or total arthroplasty of the knee were randomly assigned to either a trained group (N = 18) or an active control group (N = 16). The former received working memory training during the postoperative period, while the latter engaged in alternative activities. In addition to specific training gains in a working memory task similar to the one used in the training (criterion task), transfer effects to cognitive abilities (short- and long-term memory, and cognitive inhibition), and mood or emotional functioning (signs of depression or anxiety) were investigated.

RESULTS

Immediately after the training, results showed a main effect of group (in favor of the trained group) in the criterion task, in one of the short-term memory measures, and in cognitive inhibition. In addition, only the trained group showed a decrease in depression and anxiety scores.

CONCLUSION

The results of this pilot study suggest that cognitive training targeting working memory administered in the postoperative period after major surgery can sustain older adults' cognitive and emotional functioning, and especially their mood.

The Mediating Role of Neural Activity on the Relationship Between Childhood Maltreatment and Impulsivity

Child maltreatment is associated with a variety of risk behaviors in young adulthood; however, the underlying cognitive and neural mechanisms of this relation are not well understood. The primary aim of the present study was to examine the direct and indirect effects between maltreatment in childhood and downstream impulsivity via neural activity during a cognitive task. In a sample of emerging adult women from the rural southeastern United States, childhood abuse and neglect were assessed using the childhood trauma questionnaire. Outcome measures of neural activity during a functional magnetic resonance imaging N-back verbal working memory (WM) task and trait impulsivity on the Impulsive Behavior Scale were assessed approximately 1 year later. Results indicate that adults with higher levels of reported childhood maltreatment demonstrate worse behavioral performance and lower neural response during a difficult verbal WM task. Furthermore, neural activity significantly mediated the relation between abuse and neglect in childhood and trait impulsivity. These new findings demonstrate an association between neurocognitive functioning and reported childhood abuse and neglect, and indicate that such changes may underlie the relation between maltreatment and trait-level impulsivity.

General fluid/inductive reasoning battery for a high-ability population

The validity of studies investigating interventions to enhance fluid intelligence (Gf) depends on the adequacy of the Gf measures administered. Such studies have yielded mixed results, with a suggestion that Gf measurement issues may be partly responsible. The purpose of this study was to develop a Gf test battery comprising tests meeting the following criteria: (a) strong construct validity evidence, based on prior research; (b) reliable and sensitive to change; (c) varying in item types and content; (d) producing parallel tests, so that pretest-posttest comparisons could be made; (e) appropriate time limits; (f) unidimensional, to facilitate interpretation; and (g) appropriate in difficulty for a high-ability population, to detect change. A battery comprising letter, number, and figure series and figural matrix item types was developed and evaluated in three large-N studies (N = 3,067, 2,511, and 801, respectively). Items were generated algorithmically on the basis of proven item models from the literature, to achieve high reliability at the targeted difficulty levels. An item response theory approach was used to calibrate the items in the first two studies and to establish conditional reliability targets for the tests and the battery. On the basis of those calibrations, fixed parallel forms were assembled for the third study, using linear programming methods. Analyses showed that the tests and test battery achieved the proposed criteria. We suggest that the battery as constructed is a promising tool for measuring the effectiveness of cognitive enhancement interventions, and that its algorithmic item construction enables tailoring the battery to different difficulty targets, for even wider applications.

Improving Everyday Functioning in the Old-Old with Working Memory Training

OBJECTIVE

The aim of this study was to assess gains related to working memory (WM) training, in the short and long term (9 months after the training), in abilities required in everyday life, and in cognitive measures in old-old adults (aged ≥ 75 years).

METHODS

Thirty-two community-dwelling older adults (aged 75-85 years) were randomly assigned to a training or an active control group. In addition to testing for any specific gains in a WM task similar to the one used in the training (criterion task), we sought transfer effects to: 1) abilities involved in everyday life using objective performance-based tasks (the Everyday Problem Test [EPT] and the Timed Instrumental Activities of Daily Living [TIADL] scale; 2) tasks demanding the comprehension and recall of spatial information and pairing names with faces; and 3) a measure of inhibitory control, that is, recall errors (intrusion errors).

RESULTS

Only the trained group showed specific gains in the criterion task, and in the TIADL in the short term. At follow-up, the trained group maintained gains in the criterion task, and showed transfer effects to everyday problem-solving (in the EPT), and in constructing spatial representations of an environment. The trained group also improved in a cognitive inhibition measure (intrusion errors) at follow-up. No such improvements were seen in the active control group.

CONCLUSION

WM training may be a valid way to help old-old adults preserve at least some abilities related to everyday functioning.

Is Computerized Working Memory Training Effective in Healthy Older Adults? Evidence from a Multi-Site, Randomized Controlled Trial

BACKGROUND

Developing effective interventions to attenuate age-related cognitive decline and prevent or delay the onset of dementia are major public health goals. Computerized cognitive training (CCT) has been marketed increasingly to older adults, but its efficacy remains unclear. Working memory (WM), a key determinant of higher order cognitive abilities, is susceptible to age-related decline and a relevant target for CCT in elders.

OBJECTIVE

To evaluate the efficacy of CCT focused on WM compared to an active control condition in healthy older adults.

METHODS

Eighty-two cognitively normal adults from two sites (USA and Sweden) were randomly assigned to Cogmed Adaptive or Non-Adaptive (active control) CCT groups. Training was performed in participants' homes, five days per week over five weeks. Changes in the performance of the Cogmed trained tasks, and in five neuropsychological tests (Trail Making Test Part A and Part B, Digit Symbol, Controlled Oral Word Association Test and Semantic Fluency) were used as outcome measures.

RESULTS

The groups were comparable at baseline. The Adaptive group showed robust gains in the trained tasks, and there was a time-by-group interaction for the Digit Symbol test, with significant improvement only after Adaptive training. In addition, the magnitude of the intervention effect was similar at both sites.

CONCLUSION

Home-based CCT Adaptive WM training appears more effective than Non-Adaptive training in older adults from different cultural backgrounds. We present evidence of improvement in trained tasks and on a demanding untrained task dependent upon WM and processing speed. The benefits over the active control group suggest that the Adaptive CCT gains were linked to providing a continuously challenging level of WM difficulty.

FAST: A Novel, Executive Function-Based Approach to Cognitive Enhancement

The present study introduces a novel cognitive intervention aimed at improving fluid intelligence (Gf), based on a framework we refer to as FAST: Flexible, Adaptive, Synergistic Training. FAST leverages a combination of novel game-based executive function (EF) training—designed specifically to enhance the likelihood of transfer—and transcranial electrical stimulation (tES), with aims to synergistically activate and strengthen mechanisms of cognitive control critical to Gf. To test our intervention, we collected three Gf measures from 113 participants [the advanced short Bochumer Matrizen-Test (BOMAT), Raven’s Advanced Progressive Matrices (APM), and matrices similar to Raven’s generated by Sandia labs], prior to and following one of three interventions: (1) the FAST + tRNS intervention, a combination of 30 min of daily training with our novel training game, Robot Factory, and 20 min of concurrent transcranial random noise stimulation applied to bilateral dorsolateral prefrontal cortex (DLPFC); (2) an adaptively difficult Active Control intervention comprised of visuospatial tasks that specifically do not target Gf; or (3) a no-contact control condition. Analyses of changes in a Gf factor from pre- to post-test found numerical increases for the FAST + tRNS group compared to the two control conditions, with a 0.3 SD increase relative to Active Control (p = 0.07), and a 0.19 SD increase relative to a No-contact control condition (p = 0.26). This increase was found to be largely driven by significant differences in pre- and post-test Gf as measured on the BOMAT test. Progression through the FAST training game (Robot Factory) was significantly correlated with changes in Gf. This is in contrast with progress in the Active Control condition, as well as with changes in individual EFs during FAST training, which did not significantly correlate with changes in Gf. Taken together, this research represents a useful step forward in providing new insights into, and new methods for studying, the nature of Gf and its malleability. Though our results await replication and extension, they provide preliminary evidence that the crucial characteristic of Gf may, in fact, be the ability to combine EFs rapidly and adaptively according to changing demand, and that Gf may be susceptible to targeted training.

Cognitive and neural plasticity in old age: A systematic review of evidence from executive functions cognitive training

Cognitive training is a popular intervention aimed at attenuating age-related cognitive decline, however, the effects of this intervention on brain structure and function have not been thoroughly explored. Core executive functions (working memory, inhibition, cognitive flexibility) are dependent upon prefrontal brain regions-one of the most vulnerable areas of age-related decline. They are also implicated in numerous cognitive processes and higher-order functions. Training executive functions should therefore promote cognitive and neural enhancements in old age. This systematic review examined the effects of executive functions training on brain and cognition amongst healthy older adults across 20 studies. Behavioral performance consistently improved on trained cognitive tasks, though mixed findings were reported for untrained tasks. Training-related structural changes were reported, evidenced through increases in grey matter and cortical volume. Functional changes were not consistent, though a general pattern of increased subcortical and decreased frontal and parietal activation emerged across studies, indicating that training may potentially reduce reliance on compensatory neural mechanisms. Training executive functions appears to promote cognitive and neural plasticity in old age, though further research is required to develop a more comprehensive framework which connects and elucidates the mechanisms underlying cognitive training, cognitive transfer, and cognitive aging.

Effects of Systematic Categorization Training on Cognitive Performance in Healthy Older Adults and in Adults with Traumatic Brain Injury

This study investigated the effects of hierarchical cognitive training using the categorization program (CP), designed initially for adults with cognitive deficits associated with traumatic brain injury (TBI). Fifty-eight participants were included: a group of fifteen young adults with TBI (ages 18-48), another group of fifteen noninjured young adults (ages 18-50), and two groups of adults over 60 randomly assigned into the experimental group (n = 14) or the control group (n = 14). Following neuropsychological testing, the two young adult groups and the experimental older adult group received the CP training for 10-12 weeks. The CP training consisted of 8 levels targeting concept formation, object categorization, and decision-making abilities. Two CP tests (administered before and after the training) and three probe tasks (administered at specified intervals during the training) assessed skills relating to categorization. All treated groups showed significant improvement in their categorization performance, although younger participants (with or without TBI) demonstrated greater gains. Gains on the categorization measures were maintained by a subgroup of older adults up to four months posttraining. Implications of these findings in terms of adult cognitive learning and directions for future research on adult cognitive rehabilitation and cognitive stimulation programs are discussed.

Off-Court Generic Perceptual-Cognitive Training in Elite Volleyball Athletes: Task-Specific Effects and Levels of Transfer

Background: The nature of perceptual-cognitive expertise in interactive sports has gained more and more scientific interest over the last two decades. Research to understand how this expertise can be developed has not been addressed profoundly yet. In approaches to study this with interventional designs, only few studies have scrutinized several levels of transfer such as to the field. Therefore, the aim of this study was to examine the efficacy of a generic off-court perceptual-cognitive training in elite volleyball players on three different levels: task-specific, near-transfer, and far-transfer effects. Based on overlapping cognitive processes between training and testing, we hypothesized task-specific improvements as well as positive near- and far-transfer effects after a multiple-object tracking training intervention.

Methods: Twenty-two volleyball experts completed a 8-week three-dimensional (3D) multiple-object tracking (3D-MOT) training intervention. A control group (n = 21; volleyball experts also) participated in regular ball practice only. Before and after training, both groups performed tests on the 3D-MOT, four near-transfer tests in cognitive domains, and a far-transfer, lab-based, and volleyball-specific blocking test.

Results: The results of the 2 × 2 analysis of variance (ANOVA) (group, time) showed significant interaction effects in the 3D-MOT task [F(1,40) = 93.10; p < 0.001; ηp2 = 0.70] and in two near-transfer tests [sustained attention: F(1,40) = 15.45; p < 0.001; ηp2 = 0.28; processing speed: F(1,40) = 12.15; p = 0.001; ηp2 = 0.23]. No significant interaction effects were found in the far-transfer volleyball test.

Conclusions: Our study suggests positive effects in task-specific and two near-transfer tests of a perceptual-cognitive intervention in elite volleyball athletes. This supports a partial overlap in cognitive processing between practice and tests with the result of positive near-transfer. However, there are no significant effects in far-transfer testing. Although these current results are promising, it is still unclear how far-transfer effects of a generic perceptual-cognitive training intervention can be assured.

Mapping differential responses to cognitive training using machine learning

We used two simple unsupervised machine learning techniques to identify differential trajectories of change in children who undergo intensive working memory (WM) training. We used self‐organizing maps (SOMs)—a type of simple artificial neural network—to represent multivariate cognitive training data, and then tested whether the way tasks are represented changed as a result of training. The patterns of change we observed in the SOM weight matrices implied that the processes drawn upon to perform WM tasks changed following training. This was then combined with K‐means clustering to identify distinct groups of children who respond to the training in different ways. Firstly, the K‐means clustering was applied to an independent large sample (N = 616, M_age = 9.16 years, range = 5.16–17.91 years) to identify subgroups. We then allocated children who had been through cognitive training (N = 179, M_age = 9.00 years, range = 7.08–11.50 years) to these same four subgroups, both before and after their training. In doing so, we were able to map their improvement trajectories. Scores on a separate measure of fluid intelligence were predictive of a child's improvement trajectory. This paper provides an alternative approach to analysing cognitive training data that go beyond considering changes in individual tasks. This proof‐of‐principle demonstrates a potentially powerful way of distinguishing task‐specific from domain‐general changes following training and of establishing different profiles of response to training.

Effect of Cognitive Training on Daily Function in Older People without Major Neurocognitive Disorder: A Systematic Review

There is increasing interest in the effect of non-pharmacological treatments on preserving cognition and function in older adults without major neurocognitive disorder (dementia). However, its effect on everyday function in terms of instrumental activities of daily living (IADL) is unclear. We conducted a systematic review to examine whether cognitive training, independent of other interventions, can improve IADL function in older adults without major neurocognitive disorder. We searched multiple databases including MEDLINE, EMBASE, and PSYCINFO and found thirteen studies that met our inclusion criteria with 7130 participants in total. Six out of thirteen studies reported a significant change on validated IADL assessment. On subgroup analysis, five studies included older adults with normal cognition and one included mild cognitive impairment (MCI). Eleven out of twelve studies showed improvement in measures of cognition. None of the studies described changes in the ability to live independently. While variation in study protocol, outcome measurement, and effect size reporting precluded further inferential statistical analysis, our review found a sizable number of studies showing improvement in IADL. Cognitive training may have some benefit in improving IADL function in older adults without major neurocognitive disorder. Future long-term studies focusing on maintained IADL function and preserved independence are needed.

Parallel Changes in Cognitive Function and Gray Matter Volume After Multi-Component Training of Cognitive Control (MTCC) in Adolescents

Adolescence is a unique period in which higher cognition develops to adult-level, while plasticity of neuron and behavior is at one of its peak. Notably, cognitive training studies for adolescents has been sparse and neural correlates of the training effects yet to be established. This study investigated the effects of multi-component training of cognitive control (MTCC) in order to examine whether the training enhanced adolescents' cognitive control ability and if the effects were generalizable to other cognitive domains. Cognitive control refers to the ability to adjust a series of thoughts and behaviors in correspondence to an internal goal, and involves inhibition, working memory, shifting, and dual tasking as subcomponents. The participants were middle school students (aged 11-14) and randomly assigned to either a training group or an active control group. The training group performed 30 min of MTCC per day for 6 weeks. To identify the training effects, we examined the cognitive performance, regional gray matter, and their relationship. The training group showed modest improvement in a visuospatial fluid intelligence test (Block Design) after MTCC, which was not significant after correcting for multiple comparisons. In addition, the training effect on the gray matter volume (time × group interaction) was observed in the right inferior cortex (rIFC). While the control group showed a typical reduction in the rIFC volume, the training group showed a relative increase in the homologous region. The relative change in rIFC volume was associated with the change in Stroop performance. These results imply that MTCC may affect brain structure relevant to inhibitory control process.

A Large-Scale, Cross-Sectional Investigation Into the Efficacy of Brain Training

Brain training is a large and expanding industry, and yet there is a recurrent and ongoing debate concerning its scientific basis or evidence for efficacy. Much of evidence for the efficacy of brain training within this debate is from small-scale studies that do not assess the type of “brain training,” the specificity of transfer effects, or the length of training required to achieve a generalized effect. To explore these factors, we analyze cross-sectional data from two large Internet-cohort studies (total N = 60,222) to determine whether cognition differs at the population level for individuals who report that they brain train on different devices, and across different timeframes, with programs in common use circa 2010–2013. Examining scores for an assessment of working-memory, reasoning and verbal abilities shows no cognitive advantages for individuals who brain train. This contrasts unfavorably with significant advantages for individuals who regularly undertake other cognitive pursuits such as computer, board and card games. However, finer grained analyses reveal a more complex relationship between brain training and cognitive performance. Specifically, individuals who have just begun to brain train start from a low cognitive baseline compared to individuals who have never engaged in brain training, whereas those who have trained for a year or more have higher working-memory and verbal scores compared to those who have just started, thus suggesting an efficacy for brain training over an extended period of time. The advantages in global function, working memory, and verbal memory after several months of training are plausible and of clinically relevant scale. However, this relationship is not evident for reasoning performance or self-report measures of everyday function (e.g., employment status and problems with attention). These results accord with the view that although brain training programs can produce benefits, these might extend to tasks that are operationally similar to the training regime. Furthermore, the duration of training regime required for effective enhancement of cognitive performance is longer than that applied in most previous studies.

Far-Transfer Effects of Strategy-Based Working Memory Training

We assessed the transfer effects of training working memory strategies to a novel problem-solving task. Previous WM training studies have produced little evidence for transfer across contexts. In the current study, 64 6- to 9-year-olds were randomly assigned to one of four training conditions: semantic and rehearsal training, semantic training only, rehearsal training only, and treated control group. All training groups performed significantly better on the transfer task than the control group, but training groups did not differ significantly from each other. Implications of the findings for cognitive interventions and future WM training studies are discussed.

Monitor yourself! Deficient error-related brain activity predicts real-life self-control failures

Despite their immense relevance, the neurocognitive mechanisms underlying real-life self-control failures (SCFs) are insufficiently understood. Whereas previous studies have shown that SCFs were associated with decreased activity in the right inferior frontal gyrus (rIFG; a region involved in cognitive control), here we consider the possibility that the reduced implementation of cognitive control in individuals with low self-control may be due to impaired performance monitoring. Following a brain-as-predictor approach, we combined experience sampling of daily SCFs with functional magnetic resonance imaging (fMRI) in a Stroop task. In our sample of 118 participants, proneness to SCF was reliably predicted by low error-related activation of a performance-monitoring network (comprising anterior mid-cingulate cortex, presupplementary motor area, and anterior insula), low posterror rIFG activation, and reduced posterror slowing. Remarkably, these neural and behavioral measures predicted variability in SCFs beyond what was predicted by self-reported trait self-control. These results suggest that real-life SCFs may result from deficient performance monitoring, leading to reduced recruitment of cognitive control after responses that conflict with superordinate goals.

Neurocompensatory Effects of the Default Network in Older Adults

The hemispheric asymmetry reduction in older adults (HAROLD) is a neurocompensatory process that has been observed across several cognitive functions but has not yet been examined in relation to task-induced relative deactivations of the default mode network. The present study investigated the presence of HAROLD effects specific to neural activations and deactivations using a functional magnetic resonance imaging (fMRI) n-back paradigm. It was hypothesized that HAROLD effects would be identified in relative activations and deactivations during the paradigm, and that they would be associated with better 2-back performance. Forty-five older adults (M age = 63.8; range = 53-83) were administered a verbal n-back paradigm during fMRI. For each participant, the volume of brain response was summarized by left and right frontal regions of interest, and laterality indices (LI; i.e., left/right) were calculated to assess HAROLD effects. Group level results indicated that age was significantly and negatively correlated with LI (i.e., reduced left lateralization) for deactivations, but positively correlated with LI (i.e., increased left lateralization) for activations. The relationship between age and LI for deactivation was significantly moderated by performance level, revealing a stronger relationship between age and LI at higher levels of 2-back performance. Findings suggest that older adults may employ neurocompensatory processes specific to deactivations, and task-independent processes may be particularly sensitive to age-related neurocompensation.

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.

Brain network modularity predicts cognitive training-related gains in young adults

The brain operates via networked activity in separable groups of regions called modules. The quantification of modularity compares the number of connections within and between modules, with high modularity indicating greater segregation, or dense connections within sub-networks and sparse connections between sub-networks. Previous work has demonstrated that baseline brain network modularity predicts executive function outcomes in older adults and patients with traumatic brain injury after cognitive and exercise interventions. In healthy young adults, however, the functional significance of brain modularity in predicting training-related cognitive improvements is not fully understood. Here, we quantified brain network modularity in young adults who underwent cognitive training with casual video games that engaged working memory and reasoning processes. Network modularity assessed at baseline was positively correlated with training-related improvements on untrained tasks. The relationship between baseline modularity and training gain was especially evident in initially lower performing individuals and was not present in a group of control participants that did not show training-related gains. These results suggest that a more modular brain network organization may allow for greater training responsiveness. On a broader scale, these findings suggest that, particularly in low-performing individuals, global network properties can capture aspects of brain function that are important in understanding individual differences in learning.

Effects of neurofeedback and working memory-combined training on executive functions in healthy young adults

Given the interest in improving executive functions, the present study examines a promising combination of two training techniques: neurofeedback training (NFT) and working memory training (WMT). NFT targeted increasing the amplitude of individual's upper Alpha frequency band at the parietal midline scalp location (Pz), and WMT consisted of an established computerized protocol with working memory updating and set-shifting components. Healthy participants (n = 140) were randomly allocated to five combinations of training, including visual search training used as an active control training for the WMT; all five groups were compared to a sixth silent control group receiving no training. All groups were evaluated before and after training for resting-state electroencephalogram (EEG) and behavioral executive function measures. The participants in the silent control group were unaware of this procedure, and received one of the training protocols only after study has ended. Results demonstrated significant improvement in the practice tasks in all training groups including non-specific influence of NFT on resting-state EEG spectral topography. There was only a near transfer effect (improvement in working memory task) for WMT, which remained significant in the delayed post-test (after 1 month), in comparison to silent control group but not in comparison to active control training group. The NFT + WMT combined group showed improved mental rotation ability both in the post-training and in the follow-up evaluations. This improvement, however, did not differ significantly from that in the silent control group. We conclude that the current training protocols, including their combination, have very limited influence on the executive functions that were assessed in this study.

Effects of sustained cognitive activity on white matter microstructure and cognitive outcomes in healthy middle-aged adults: A systematic review

Adults who remain cognitively active may be protected from age-associated changes in white matter (WM) and cognitive decline. To determine if cognitive activity is a precursor for WM plasticity, the available literature was systematically searched for Region of Interest (ROI) and whole-brain studies assessing the efficacy of cognitive training (CT) on WM microstructure using Diffusion Tensor Imaging (DTI) in healthy adults (> 40 years). Seven studies were identified and included in this review. Results suggest there are beneficial effects to WM microstructure after CT in frontal and medial brain regions, with some studies showing improved performance in cognitive outcomes. Benefits of CT were shown to be protective against age-related WM microstructure decline by either maintaining or improving WM after training. These results have implications for determining the capacity for training-dependent WM plasticity in older adults and whether CT can be utilised to prevent age-associated cognitive decline. Additional studies with standardised training and imaging protocols are needed to confirm these outcomes.

A game-based neurofeedback training system to enhance cognitive performance in healthy elderly subjects and in patients with amnestic mild cognitive impairment

INTRODUCTION

This study examines the clinical efficacy of a game-based neurofeedback training (NFT) system to enhance cognitive performance in patients with amnestic mild cognitive impairment (aMCI) and healthy elderly subjects. The NFT system includes five games designed to improve attention span and cognitive performance. The system estimates attention levels by investigating the power spectrum of Beta and Alpha bands.

METHODS

We recruited 65 women with aMCI and 54 healthy elderly women. All participants were treated with care as usual (CAU); 58 were treated with CAU + NFT (20 sessions of 30 minutes each, 2-3 sessions per week), 36 with CAU + exergame-based training, while 25 patients had only CAU. Cognitive functions were assessed using the Cambridge Neuropsychological Test Automated Battery both before and after treatment.

RESULTS

NFT significantly improved rapid visual processing and spatial working memory (SWM), including strategy, when compared with exergame training and no active treatment. aMCI was characterized by impairments in SWM (including strategy), pattern recognition memory, and delayed matching to samples.

CONCLUSION

In conclusion, treatment with NFT improves sustained attention and SWM. Nevertheless, NFT had no significant effect on pattern recognition memory and short-term visual memory, which are the other hallmarks of aMCI. The NFT system used here may selectively improve sustained attention, strategy, and executive functions, but not other cognitive impairments, which characterize aMCI in women.

Nearest transfer effects of working memory training: A comparison of two programs focused on working memory updating

This study analyzed the mechanisms involved in possible transfer effects for two different working memory updating (WMU) training programs administered to young adults and based on two updating paradigms: n-back and arithmetical updating. The influence of practice distribution on transfer effects was also explored by including two training regimens: massed and spaced practice. Performance on different WMU tasks more or less structurally similar to the tasks used in the training was assessed to analyze the nearest transfer effects. Near and far transfer effects were tested using complex working memory (WM) and fluid intelligence tasks. The results showed that the WMU training produced gains in only some of the WMU tasks structurally similar to those used in the training, not in those lacking the same structure, or in WM or fluid intelligence tasks. These limited nearest transfer effects suggest that gains could be due to the acquisition of a specific strategy appropriate for the task during the training rather than to any improvement in the updating process per se. Performance did not differ depending on the training regimen.

Retest effects in working memory capacity tests: A meta-analysis

The repeated administration of working memory capacity tests is common in clinical and research settings. For cognitive ability tests and different neuropsychological tests, meta-analyses have shown that they are prone to retest effects, which have to be accounted for when interpreting retest scores. Using a multilevel approach, this meta-analysis aims at showing the reproducibility of retest effects in working memory capacity tests for up to seven test administrations, and examines the impact of the length of the test-retest interval, test modality, equivalence of test forms and participant age on the size of retest effects. Furthermore, it is assessed whether the size of retest effects depends on the test paradigm. An extensive literature search revealed 234 effect sizes from 95 samples and 68 studies, in which healthy participants between 12 and 70 years repeatedly performed a working memory capacity test. Results yield a weighted average of g = 0.28 for retest effects from the first to the second test administration, and a significant increase in effect sizes was observed up to the fourth test administration. The length of the test-retest interval and publication year were found to moderate the size of retest effects. Retest effects differed between the paradigms of working memory capacity tests. These findings call for the development and use of appropriate experimental or statistical methods to address retest effects in working memory capacity tests.