Exploring Working Memory Capacity and Efficiency Processes to Understand Working Memory Training Outcomes in Primary School Children

Despite the abundance of research evaluating working memory training outcomes in children, few studies have examined the underlying cognitive mechanisms. This study aimed to contribute understanding by exploring whether working memory capacity (maximum span) and/or efficiency (basic and cognitive processing speeds), two proposed cognitive mechanisms, are associated with children's working memory performance immediately and 6-months post-intervention. We used data from a previous trial in primary school children (7-11 years) who completed working memory training (n = 52) or an active control (n = 36), comprising 10 sessions (each 20-minutes) in class over two weeks. Children completed five working memory measures at baseline, immediately and 6-months post-intervention: two Backwards Span and two Following Instructions measures (same paradigms as training activities), and one n-back measure (different paradigm). Maximum span, basic and cognitive processing speeds, and performance were calculated for each measure. Associations between change in maximum span, processing speeds and change in performance on the working memory measures from baseline to immediately and 6-months post-intervention did not differ between groups (all p < .05). Maximum span, processing speeds and performance on working memory measures did not differ between groups. Findings provide little evidence that the studied capacity or efficiency processes contribute to understanding working memory training outcomes in primary school children. Furthermore, working memory training did not have benefits for children's working capacity, efficiency or performance up to 6-months post-intervention. It is of interest for future studies to explore cognitive mechanisms, including strategy use, maximum span and information processing, in datasets where training effects are observed.

Can Emotional Working Memory Training Improve Cognitive Behavioral Therapy Outcomes for Social Anxiety Disorder: A Pilot Study

Social anxiety disorder (SAD) models highlight maladaptive attention as a maintaining factor of SAD, potentially negatively impacting how individuals with SAD engage with cognitive behavioral therapy (CBT) content in a therapist's presence. Emotional working memory training (eWMT) has been shown to improve affective attentional control. This pilot study assessed the proposed methodology for a randomized controlled trial (RCT) to determine whether eWMT, by improving attentional control prior to internet-based CBT (iCBT), results in better CBT outcomes. The RCT would be considered feasible if the pilot study achieved rates ≥80% for eligible participants recruited, study measures completion, intervention completion, and participant retention. Results from 10 randomized participants showed rates ≥80% for recruitment of eligible participants and iCBT intervention completion. Completion of study measures, eWMT and Placebo training interventions, and participant retention were <80%. Results highlight the need to consider strategies to improve the methodology prior to the RCT.

Working memory training in children with neurodevelopmental disorders and intellectual disabilities, the role of coaching: A double-blind randomised controlled trial

BACKGROUND

Working memory training (WMT) can offer therapeutic benefits to patients with neurodevelopmental disorders (NDD) and mild to borderline intellectual disability (MBID). However, consistent evidence for treatment benefits of WMT over placebo training is missing. So far, participants in double-blind research designs did receive non-specific coaching, whereas active coaching based on individual training results might increase the efficacy of WMT. Furthermore, the intensity and duration of WMT is often too stressful for these children. This study therefore investigated whether a less intensive but more prolonged WMT, with active personalised coaching and feedback, would reduce behavioural symptoms and improve neurocognitive functioning and academic achievements in children with NDD and MBID.

METHOD

A double-blind randomised controlled trial in children (aged 10;0-13;11) with MBID (60 < IQ < 85) and ADHD and/or ASD evaluated the effects of a less intensive but prolonged version of the original Cogmed WMT (30 min a day, 4 days a week, 8 weeks in total). Eighteen participants received active, personalised coaching and feedback, based on their actual individual performance during training. Twenty-two received general non-personalised coaching for the same amount of time. Executive functioning, academic achievements and several behavioural measurements were administered, before and after training, with a 6-months follow-up.

RESULTS

We observed a significant effect of time on both primary and secondary outcome measures, indicating that all children improved in working memory performance and other neurocognitive and academic outcomes. The interaction between time and group was not significant.

DISCUSSION

This study was unable to document superior effects of active personalised coaching and feedback compared with general non-personalised coaching and no feedback in an adaptive WMT in children with MBID and NDD. The objectively documented changes over time suggest that for these vulnerable children, a regular, structured and structural contact with a coach and adapted exercises is enough to develop therapy fidelity, boost motivation and improve neurodevelopmental task performance. Further research is needed to examine which possible subgroups within this heterogenic group of children profit more from WMT compared with other subgroups.

Working Memory Training in Norwegian Children with Cerebral Palsy (CP) Show Minimal Evidence of Near and No Far Transfer Effects

In children with cerebral palsy (CP), learning disabilities are well documented, and impairments in executive functions, such as attention, inhibition, shifting and working memory, represent significant burdens on patients, their families and the society. The aim of this study was to evaluate whether Cogmed RM working memory training could improve working memory in children with CP and investigate whether increased working memory capacity would generalize to other cognitive functions. Twenty-eight children completed the training and the results were compared to a waitlist control group (n = 32). The results yielded three main findings. First, children with CP improved with practice on trained working memory tasks. Second, the intervention group showed minimal near transfer effects to non-trained working memory tasks. Third, no effects on cognitive and behavioral far transfer measures were found.

Computerized working memory training for adults with ADHD in a psychiatric outpatient context-a feasibility trial

This study investigated the feasibility (treatment completion, and acceptability) and preliminary effectiveness of computerized working memory (WM) training in a psychiatric outpatient context for adults with ADHD. Self-ratings, neuropsychological tests, and clinician's assessments were performed pre- and post-Cogmed WM training, as well as at the 2-month follow-up, which included 24 (age M = 36.75 SD = 8.37) participants. Of the 24 participants, 16 (66.67%) completed the 25 sessions within 7 weeks. Completers reported high treatment credibility, but a few spontaneously reported feeling stressed because of the time-consuming nature of the WM training (n = 4). Preliminary effectiveness analyses indicate fewer cognitive difficulties and increased neuropsychological performance in non-trained tests that remained stable at follow-up. Future development of WM training paradigms could investigate ways of making the perception of training experience less demanding regarding being time-consuming. The indication of preliminary effectiveness merits further randomized controlled studies in a clinical context.

Experimental investigation of training schedule on home-based working memory training in healthy older adults

Introduction

The efficacy of working memory training (WMT) for cognitive enhancement in healthy older adults has been extensively investigated. Typically, WMT results in improved performance on the training task, but limited or no transfer of improvement to other cognitive tasks. Accordingly, there is a need to identify optimal intervention parameters to maximize training and transfer task effects of WMT. The current study aimed to investigate the effect of training schedule on training and transfer task performance of WMT in healthy older adults. A secondary aim was to examine the feasibility of participants performing the intervention online at home, unsupervised, and using their personal devices.

Methods

Participants (N = 71; mean age: 66 years) completed sixteen WMT or active-control sessions over eight (distributed) or four (intensive) weeks. Adaptive verbal and spatial n-back tasks were used as the WMT tasks. We tested near transfer effects to a digit-span task and far transfer effects to an abstract relational reasoning task.

Results

Participants successfully performed the cognitively demanding intervention using their own devices, online at home, and with minimal contact with the researcher. We observed a significant improvement in WMT task performance in the WMT group relative to active-controls, but no evidence of near or far transfer. Similar training effects were observed irrespective of the intensity of the training schedule.

Discussion

Our results suggest that comparable benefits could be observed when using less intensive schedules that may be more easily accommodated into everyday life.

Cognitive Training: A Field in Search of a Phenomenon

Considerable research has been carried out in the last two decades on the putative benefits of cognitive training on cognitive function and academic achievement. Recent meta-analyses summarizing the extent empirical evidence have resolved the apparent lack of consensus in the field and led to a crystal-clear conclusion: The overall effect of far transfer is null, and there is little to no true variability between the types of cognitive training. Despite these conclusions, the field has maintained an unrealistic optimism about the cognitive and academic benefits of cognitive training, as exemplified by a recent article (Green et al., 2019). We demonstrate that this optimism is due to the field neglecting the results of meta-analyses and largely ignoring the statistical explanation that apparent effects are due to a combination of sampling errors and other artifacts. We discuss recommendations for improving cognitive-training research, focusing on making results publicly available, using computer modeling, and understanding participants' knowledge and strategies. Given that the available empirical evidence on cognitive training and other fields of research suggests that the likelihood of finding reliable and robust far-transfer effects is low, research efforts should be redirected to near transfer or other methods for improving cognition.

Independent Component and Graph Theory Analyses Reveal Normalized Brain Networks on Resting-State Functional MRI After Working Memory Training in People With HIV

BACKGROUND

Cognitive training may partially reverse cognitive deficits in people with HIV (PWH). Previous functional MRI (fMRI) studies demonstrate that working memory training (WMT) alters brain activity during working memory tasks, but its effects on resting brain network organization remain unknown.

PURPOSE

To test whether WMT affects PWH brain functional connectivity in resting-state fMRI (rsfMRI).

STUDY TYPE

Prospective.

POPULATION

A total of 53 PWH (ages 50.7 ± 1.5 years, two women) and 53 HIV-seronegative controls (SN, ages 49.5 ± 1.6 years, six women).

FIELD STRENGTH/SEQUENCE

Axial single-shot gradient-echo echo-planar imaging at 3.0 T was performed at baseline (TL1), at 1-month (TL2), and at 6-months (TL3), after WMT.

ASSESSMENT

All participants had rsfMRI and clinical assessments (including neuropsychological tests) at TL1 before randomization to Cogmed WMT (adaptive training, n = 58: 28 PWH, 30 SN; nonadaptive training, n = 48: 25 PWH, 23 SN), 25 sessions over 5-8 weeks. All assessments were repeated at TL2 and at TL3. The functional connectivity estimated by independent component analysis (ICA) or graph theory (GT) metrics (eigenvector centrality, etc.) for different link densities (LDs) were compared between PWH and SN groups at TL1 and TL2.

STATISTICAL TESTS

Two-way analyses of variance (ANOVA) on GT metrics and two-sample t-tests on FC or GT metrics were performed. Cognitive (eg memory) measures were correlated with eigenvector centrality (eCent) using Pearson's correlations. The significance level was set at P < 0.05 after false discovery rate correction.

RESULTS

The ventral default mode network (vDMN) eCent differed between PWH and SN groups at TL1 but not at TL2 (P = 0.28). In PWH, vDMN eCent changes significantly correlated with changes in the memory ability in PWH (r = -0.62 at LD = 50%) and vDMN eCent before training significantly correlated with memory performance changes (r = 0.53 at LD = 50%).

DATA CONCLUSION

ICA and GT analyses showed that adaptive WMT normalized graph properties of the vDMN in PWH.

EVIDENCE LEVEL

1 TECHNICAL EFFICACY: 1.

Expectation effects in working memory training

There is a growing body of research focused on developing and evaluating behavioral training paradigms meant to induce enhancements in cognitive function. It has recently been proposed that one mechanism through which such performance gains could be induced involves participants' expectations of improvement. However, no work to date has evaluated whether it is possible to cause changes in cognitive function in a long-term behavioral training study by manipulating expectations. In this study, positive or negative expectations about cognitive training were both explicitly and associatively induced before either a working memory training intervention or a control intervention. Consistent with previous work, a main effect of the training condition was found, with individuals trained on the working memory task showing larger gains in cognitive function than those trained on the control task. Interestingly, a main effect of expectation was also found, with individuals given positive expectations showing larger cognitive gains than those who were given negative expectations (regardless of training condition). No interaction effect between training and expectations was found. Exploratory analyses suggest that certain individual characteristics (e.g., personality, motivation) moderate the size of the expectation effect. These results highlight aspects of methodology that can inform future behavioral interventions and suggest that participant expectations could be capitalized on to maximize training outcomes.

Immediate and Sustained Effects of Neurofeedback and Working Memory Training on Cognitive Functions in Children and Adolescents with ADHD: A Multi-Arm Pragmatic Randomized Controlled Trial

OBJECTIVE

To evaluate the effects of neurocognitive training methods on targeted cognitive functions in children and adolescent with ADHD.

METHOD

A pragmatic four-arm randomized controlled trial compared two types of neurofeedback (Slow Cortical Potential and Live Z-score) and Working-memory training (WMT) with treatment as usual. N = 202 participants with ADHD aged 9 to 17 years were included. A battery of cognitive function tests was completed pretreatment, posttreatment, and after 6-months.

RESULTS

The effects of WMT on spatial and verbal working-memory were superior to neurofeedback and treatment as usual at posttreatment, but only partially sustained at follow-up. No other consistent effects were observed. We found no clear indications that effects were moderated by ADHD presentation, ongoing medication, age, or sex.

CONCLUSION

The sustained effects of neurocognitive training on cognitive functioning in children and adolescents with ADHD may be limited. Future research should focus on more personalized forms of neurocognitive training.

Tactile angle discriminability improvement: Contributions of working memory training and continuous attended sensory input

Perceptual learning is commonly assumed to enhance perception through continuous attended sensory input. However, learning is generalizable to performance in untrained stimuli and tasks. Although previous studies have observed a possible generalization effect across tasks as a result of working memory (WM) training, comparisons of the contributions of WM training and continuous attended sensory input to perceptual learning generalization are still rare. Therefore, we compared which factors contributed most to perceptual generalization and investigated which skills acquired during WM training led to tactile generalization across tasks. Here, a Braille-like dot pattern matching n-back WM task was used as the WM training task, with four workload levels (0, 1, 2, and 3-back levels). A tactile angle discrimination (TAD) task was used as a pre- and posttest to assess improvements in tactile perception. Between tests, four subject groups were randomly assigned to four different workload n-back tasks to consecutively complete three sessions of training. The results showed that tactile n-back WM training could enhance TAD performance, with the 3-back training group having the highest TAD threshold improvement rate. Furthermore, the rate of WM capacity improvement on the 3-back level across training sessions was correlated with the rate of TAD threshold improvement. These findings suggest that continuous attended sensory input and enhanced WM capacity can lead to improvements in TAD ability, and that greater improvements in WM capacity can predict greater improvements in TAD performance.

NEW & NOTEWORTHY Perceptual learning is not always specific to the trained task and stimuli. We demonstrate that both continuous attended sensory input and improved WM capacity can be used to enhance tactile angle discrimination (TAD) ability. Moreover, WM capacity improvement is important in generalizing the training effect to the TAD ability. These findings contribute to understanding the mechanism of perceptual learning generalization across tasks.

When expanding training from working memory to emotional working memory: not only improving explicit emotion regulation but also implicit negative control for anxious individuals

BACKGROUND

The effect of working memory training (WM-T) has been found to transfer to emotional wellbeing, despite some debate on whether an affective component in training is necessary to achieve specific emotion-related benefits. These novel cognitive trainings have not yet been tested in highly anxious individuals, who have deficits in implicit and explicit emotional regulation and should be the potential beneficiaries of these trainings.

METHODS

We designed two types of mobile phone-based training applications: (1) WMT and (2) an emotional working memory training (EWM-T) that comprised negative face distraction. Ninety-eight participants (33, WM-T; 35, EWM-T; 30, Control group) with high trait anxiety completed the 21-day intervention or placebo program and conducted pre- and post-test procedures, including questionnaires, emotional regulation and emotional Stroop tasks alongside electroencephalogram recording. Late positive potential (LPP) in emotion regulation task and P3 in the emotional Stroop task were adopted as neutral indicators for the explicit and implicit affective regulation/control processing.

RESULTS

Those who had received training (WM-T and EWM-T) showed enhanced explicit regulation (indexed by reduced LPP during reappraisal) compared with the control. Besides, individuals in EWM-T showed reduced behavioral attention bias and a decline of P3 in response to negative faces in an emotional Stroop task. The altered neural indicators were correlated with corresponding behavior indexes that contributed to the anxiety alleviation.

CONCLUSIONS

The general WM-T was effective in enhancing explicit emotional regulation, while training with emotional add-in further improved implicit emotional control. (E)WM-T shows potential as a beneficial intervention for the anxiety population.

Working memory training in children with borderline intellectual functioning and neuropsychiatric disorders: a triple-blind randomised controlled trial

BACKGROUND

Poor working memory, lower IQ and maladaptive behaviour form a triple disability known to have negative effects on the academic and social development of children with borderline intellectual functioning (BIF; IQ: 70 < IQ < 85) and neuropsychiatric disorders [attention-deficit hyperactivity disorder (ADHD) and/or autism spectrum disorder (ASD)]. Treatment possibilities for these children are scarce and hardly evidence based. This study primarily investigated whether adaptive computerised working memory training (WMT) may lead to significantly more improvement on a non-trained visuospatial WM task compared with a non-adaptive control WMT (placebo) in children with BIF and neuropsychiatric disorders. As secondary outcome measures, we used the scores on several non-trained neuropsychological near-transfer and far-transfer tasks as well as behavioural measures.

METHOD

We conducted a triple-blind placebo-controlled randomised clinical trial in 72 children (aged 10;0-13;11 years, 53 boys, 19 girls) with BIF and comorbid neuropsychiatric disorders (ADHD = 37, ASD = 21, both = 14) that were referred to child and adolescent psychiatry care, between May 2012 and March 2019. Children completed the Dutch version of Cogmed WMT, either the adaptive training version or the non-adaptive placebo version, 25 sessions (30-45 min a day), for 5 weeks. The primary outcome measure was the score on a non-trained visuospatial working memory task. The primary outcome was measured before and directly after 5 weeks of WMT and again 6 months after training.

RESULTS

A total of 375 children were screened for eligibility and 72 were randomised. No significantly higher levels of improvement over time were found on our primary outcome measure in the experimental WMT group compared with the placebo control WMT, nor in the secondary (near-transfer and far-transfer tasks) or tertiary (behavioural measures) outcome measures. However, this study did show changes over time for these measurements for both the experimental and placebo conditions.

CONCLUSIONS

This study was unable to document superior training effects over time of an adaptive WMT in children with BIF and neuropsychiatric disorders, compared with a placebo (non-adaptive) WMT. The objectively documented changes over time in the non-adaptive WMT arm suggest that these children with persistent impairments in WM may benefit from a structured learning environment that is associated with improvement of neurocognitive functioning and coping strategies. Further research is needed to examine which elements of cognitive training may be useful for which specific patients and to study long-term effects of training.

The Mindset of Intelligence Is Not a Contributor of Placebo Effects in Working Memory Training

Whether working memory training is effective in enhancing fluid intelligence remains in dispute. Several researchers, who doubt the training benefits, consider that placebo effects may be the reason for positive training gains. One of the vital variables that may induce the placebo effect is the mindset of intelligence. In this article, we provide a test of whether the mindset of intelligence leads to placebo effects in working memory training. Participants were overtly recruited and allocated to the growth mindset group or the fixed mindset group by Theories of Intelligence Scale scores. A single, 1 h session working memory training is the cue to introduce the placebo effects. During pre/post-testing, all participants completed tasks measuring working memory capacity (near transfer) and fluid intelligence (far transfer). Our findings show no significant difference between the two groups in both tasks. Therefore, these results suggest that the placebo effect does not exist in this study, which means individuals' mindset of intelligence may not be a contributor to the placebo effect in 1 h working memory training. This research will further help to clarify the mechanism of the placebo effect in working memory training.

The VNTR of the AS3MT gene is associated with brain activations during a memory span task and their training-induced plasticity

BACKGROUND

The Arsenic (+3 oxidation state) methyltransferase (AS3MT) gene has been identified as a top risk gene for schizophrenia in several large-scale genome-wide association studies. A variable number tandem repeat (VNTR) of this gene is the most significant expression quantitative trait locus, but its role in brain activity in vivo is still unknown.

METHODS

We first performed a functional magnetic resonance imaging (fMRI) scan of 101 healthy subjects during a memory span task, trained all subjects on an adaptive memory span task for 1 month, and finally performed another fMRI scan after the training. After excluding subjects with excessive head movements for one or more scanning sessions, data from 93 subjects were included in the final analyses.

RESULTS

The VNTR was significantly associated with both baseline brain activation and training-induced changes in multiple regions including the prefrontal cortex and the anterior and posterior cingulate cortex. Additionally, it was associated with baseline brain activation in the striatum and the parietal cortex. All these results were corrected based on the family-wise error rate method across the whole brain at the peak level.

CONCLUSIONS

This study sheds light on the role of AS3MT gene variants in neural plasticity related to memory span training.

Working Memory Training Effects on White Matter Integrity in Young and Older Adults

OBJECTIVES

Working memory is essential for daily life skills like reading comprehension, reasoning, and problem-solving. Healthy aging of the brain goes along with working memory decline that can affect older people's independence in everyday life. Interventions in the form of cognitive training are a promising tool for delaying age-related working memory decline, yet the underlying structural plasticity of white matter is hardly studied.

METHODS

We conducted a longitudinal diffusion tensor imaging study to investigate the effects of an intensive four-week adaptive working memory training on white matter integrity quantified by global and tract-wise mean diffusivity. We compared diffusivity measures of fiber tracts that are associated with working memory of 32 young and 20 older participants that were randomly assigned to a working memory training group or an active control group.

RESULTS

The behavioral analysis showed an increase in working memory performance after the four-week adaptive working memory training. The neuroanatomical analysis revealed a decrease in mean diffusivity in the working memory training group after the training intervention in the right inferior longitudinal fasciculus for the older adults. There was also a decrease in mean diffusivity in the working memory training group in the right superior longitudinal fasciculus for the older and young participants after the intervention.

CONCLUSION

This study shows that older people can benefit from working memory training by improving their working memory performance that is also reflected in terms of improved white matter integrity in the superior longitudinal fasciculus and the inferior longitudinal fasciculus, where the first is an essential component of the frontoparietal network known to be essential in working memory.

Cortical and subcortical responsiveness to intensive adaptive working memory training: An MRI surface-based analysis

Working memory training (WMT) has been shown to have effects on cognitive performance, the precise effects and the underlying neurobiological mechanisms are, however, still a matter of debate. In particular, the impact of WMT on gray matter morphology is still rather unclear. In the present study, 59 healthy middle‐aged participants (age range 50–65 years) were pseudo‐randomly single‐blinded allocated to an 8‐week adaptive WMT or an 8‐week nonadaptive intervention. Before and after the intervention, high resolution magnetic resonance imaging (MRI) was performed and cognitive test performance was assessed in all participants. Vertex‐wise cortical volume, thickness, surface area, and cortical folding was calculated. Seven subcortical volumes of interest and global mean cortical thickness were also measured. Comparisons of symmetrized percent change (SPC) between groups were conducted to identify group by time interactions. Greater increases in cortical gyrification in bilateral parietal regions, including superior parietal cortex and inferior parietal lobule as well as precuneus, greater increases in cortical volume and thickness in bilateral primary motor cortex, and changes in surface area in bilateral occipital cortex (medial and lateral occipital cortex) were detected in WMT group after training compared to active controls. Structural training‐induced changes in WM‐related regions, especially parietal regions, might provide a better brain processing environment for higher WM load.

Working Memory Training in Amnestic and Non-amnestic Patients With Mild Cognitive Impairment: Preliminary Findings From Genotype Variants on Training Effects

Working memory training (WMT) effects may be modulated by mild cognitive impairment (MCI) subtypes, and variations in APOE-epsilon (APOE-ε) and LMX1A genotypes. Sixty-one individuals (41 men/20 women, mean age 66 years) diagnosed with MCI (31 amnestic/30 non-amnestic) and genotyped for APOE-ε and LMX1A completed 4 weeks/20-25 sessions of WMT. Cognitive functions were assessed before, 4 weeks and 16 weeks after WMT. Except for Processing Speed, the non-amnestic MCI group (naMCI) outperformed the amnestic MCI (aMCI) group in all cognitive domains across all time-points. At 4 weeks, working memory function improved in both groups (p < 0.0001), but at 16 weeks the effects only remained in the naMCI group. Better performance was found after training for the naMCI patients with LMX1A-AA genotype and for the APOE-ε4 carriers. Only the naMCI-APOE-ε4 group showed improved Executive Function at 16 weeks. WMT improved working memory and some non-trained cognitive functions in individuals with MCI. The naMCI group had greater training gain than aMCI group, especially in those with LMX1A-AA genotype and among APOE-ε4-carriers. Further research with larger sample sizes for the subgroups and longer follow-up evaluations is warranted.

A Systematic Review on Predictors of Working Memory Training Responsiveness in Healthy Older Adults: Methodological Challenges and Future Directions

Background: Research on predictors of working memory training responsiveness, which could help tailor cognitive interventions individually, is a timely topic in healthy aging. However, the findings are highly heterogeneous, reporting partly conflicting results following a broad spectrum of methodological approaches to answer the question “who benefits most” from working memory training.

Objective: The present systematic review aimed to systematically investigate prognostic factors and models for working memory training responsiveness in healthy older adults.

Method: Four online databases were searched up to October 2019 (MEDLINE Ovid, Web of Science, CENTRAL, and PsycINFO). The inclusion criteria for full texts were publication in a peer-reviewed journal in English/German, inclusion of healthy older individuals aged ≥55 years without any neurological and/or psychiatric diseases including cognitive impairment, and the investigation of prognostic factors and/or models for training responsiveness after targeted working memory training in terms of direct training effects, near-transfer effects to verbal and visuospatial working memory as well as far-transfer effects to other cognitive domains and behavioral variables. The study design was not limited to randomized controlled trials.

Results: A total of 16 studies including n = 675 healthy older individuals with a mean age of 63.0–86.8 years were included in this review. Within these studies, five prognostic model approaches and 18 factor finding approaches were reported. Risk of bias was assessed using the Quality in Prognosis Studies checklist, indicating that important information, especially regarding the domains study attrition, study confounding, and statistical analysis and reporting, was lacking throughout many of the investigated studies. Age, education, intelligence, and baseline performance in working memory or other cognitive domains were frequently investigated predictors across studies.

Conclusions: Given the methodological shortcomings of the included studies, no clear conclusions can be drawn, and emerging patterns of prognostic effects will have to survive sound methodological replication in future attempts to promote precision medicine approaches in the context of working memory training. Methodological considerations are discussed, and our findings are embedded to the cognitive aging literature, considering, for example, the cognitive reserve framework and the compensation vs. magnification account. The need for personalized cognitive prevention and intervention methods to counteract cognitive decline in the aging population is high and the potential enormous.

Registration: PROSPERO, ID CRD42019142750.

The effect of high vs. low intensity neuropsychological treatment on working memory in patients with acquired brain injury

AIM

To evaluate the combined effect of compensation therapy and functional training on working memory (WM) in patients with acquired injury and chronic cognitive deficits by investigating the dose-response relationship and specificity of transfer effects.

RESEARCH DESIGN

Double-blind randomized controlled trial.

METHODS

All patients underwent 4 weeks of compensation therapy in a day-care setting. In addition, they received either 20 sessions of computer-based WM training (n = 11) or attention training (n = 9). Transfer effects on cognition and their functional relevance in daily life were assessed before treatment, after 2 weeks (10 additional training sessions), and after 4 weeks (20 additional training sessions) of therapy.

RESULTS

The combined treatment led to significant improvements in WM performance, verbal memory, and self-reported changes in daily life. The amount of training was identified to modulate efficacy: Significant improvements showed only in the later training phase. We observed no differences between the two training schemes (WM vs. attentional training).

CONCLUSIONS

Even in the chronic phase after brain lesion WM performance can be enhanced by the combination of compensation therapy and computerized cognitive training when applied intensely; both a more general attention and a specific WM training regimen are effective.

N-Back Task Training Helps to Improve Post-error Performance

Improved performance on working memory (WM) through training has been widely expected to transfer to other domains. Recent studies have proposed that WM training could enhance the autonomous coordination of WM processes. Based on the shared processes between WM and error processing, our present study explored the transfer effect of 15 days of training on post-error performance, during the n-back task, compared to a simple visual search task. Participants were randomly assigned to either the training (N = 22) or control (N = 18) group. We found that WM training successfully improved WM performance. After training, compared with the control group, the training group showed a significant reduction in post-error slowing (PES); however, post-error accuracy and the flanker effect were not modulated by WM training. Moreover, we observed a significant, negative correlation between the changes in PES and WM from pretest to posttest and classified two groups based on these changes in PES with 70% accuracy. Thus, in our present sample, WM training improved post-error performance. We propose that the skill of controlling information flow, developed during WM training, is transferable to other tasks and discuss the implications of current findings for understanding the generation of PES.

Effects of working memory training on emotion regulation: Transdiagnostic review

Working memory training is widely used transdiagnostically to improve cognition. However, more recently, studies using working memory training packages have targeted emotion-regulation outcomes to determine whether far transfer effects can be achieved. A narrative review is conducted of studies that have used standardized computerized working memory training packages across healthy volunteers, affect, anxiety, post-traumatic stress disorder (PTSD), and eating disordered populations with emotion-regulation outcomes. Working memory training has been used in children, adolescents, and adults to improve emotion regulation. Many studies have reported gains in mood as well as emotion-regulation strategies following working memory training, regardless of clinical indication and whether near transfer gains were achieved in cognitive domains. Significant emotion-regulation outcomes include: state and trait anxiety, rumination, brooding, positive appraisal, decreasing maladaptive emotion-regulation strategies, and decreasing intrusive thoughts. It is speculated that these far transfer outcomes from working memory training are possible due to the cognitive and neural overlap between cognitive and affective working memory, and emotion regulation. Working memory training could improve cognitive efficiency, which, in turn, increases the availability of cognitive resources during times when emotion regulation is taxed. Future studies need to consider the role of participant expectancy in predicting outcome measure performance, and including subjective and objective outcomes is paramount to study design. Furthermore, sample sizes require additional attention, given that the current review highlights that individual differences in non-clinical and clinical populations influence the outcomes from working memory training. Working memory training offers a possibility for improving emotion regulation transdiagnostically.

Evidence for the contribution of COMT gene Val158/108Met polymorphism (rs4680) to working memory training-related prefrontal plasticity

BACKGROUND

Genetic factors have been suggested to affect the efficacy of working memory training. However, few studies have attempted to identify the relevant genes.

METHODS

In this study, we first performed a randomized controlled trial (RCT) to identify brain regions that were specifically affected by working memory training. Sixty undergraduate students were randomly assigned to either the adaptive training group (N = 30) or the active control group (N = 30). Both groups were trained for 20 sessions during 4 weeks and received fMRI scans before and after the training. Afterward, we combined the data from the 30 participants in the RCT study who received adaptive training with data from 71 additional participants who also received the same adaptive training but were not part of the RCT study (total N = 101) to test the contribution of the COMT Val158/108Met polymorphism to the interindividual difference in the training effect within the identified brain regions.

RESULTS

In the RCT study, we found that the adaptive training significantly decreased brain activation in the left prefrontal cortex (TFCE-FWE corrected p = .030). In the genetic study, we found that compared with the Val allele homozygotes, the Met allele carriers' brain activation decreased more after the training at the left prefrontal cortex (TFCE-FWE corrected p = .025).

CONCLUSIONS

This study provided evidence for the neural effect of a visual-spatial span training and suggested that genetic factors such as the COMT Val158/108Met polymorphism may have to be considered in future studies of such training.

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).

Review of the Neural Processes of Working Memory Training: Controlling the Impulse to Throw the Baby Out With the Bathwater

BACKGROUND

Smartphone technology has enabled the creation of many working memory training (WMT) Apps, with those peer-reviewed described in a recent review. WMT claims to improve working memory, attention deficits, hyperactivity and fluid intelligence, in line with plasticity brain changes. Critics argue that WMT is unable to achieve "far-transfer"-the attainment of benefits to cognition from one taught context to another dissimilar context-associated with improved quality of life. However, brain changes after a course of WMT in frontoparietal and striatal circuits-that often occur prior to behavioral changes-may be a better indicator of far-transfer efficacy, especially to improve impulse control commonly dysregulated in those with addictive disorders, yet not commonly examined in WMT studies.

METHOD

In contrast to previous reviews, the aim here is to focus on the findings of brain imaging WMT training studies across various imaging modalities that use various paradigms, published via PubMed, Scopus, Medline, and Google Scholar.

RESULTS

35 brain imaging studies utilized fMRI, structural imaging (MRI, DTI), functional connectivity, EEG, transcranial direct current stimulation (tDCS), cerebral perfusion, and neurogenetic analyses with tasks based on visuospatial and auditory working memory, dual and standard n-back.

DISCUSSION

Evidence suggests that repeated WMT reduces brain activation in frontoparietal and striatal networks reflective of increased neural circuitry efficiency via myelination and functional connectivity changes. Neural effects of WMT may persist months after training has ended, lead to non-trained task transfer, be strengthened by auxiliary methods such as tDCS and be related to COMT polymorphisms. WMT could be utilized as an effective, non-invasive intervention for working memory deficits to treat impulse and affective control problems in people with addictive disorders.

Neural and Behavioral Effects of an Adaptive Online Verbal Working Memory Training in Healthy Middle-Aged Adults

Neural correlates of working memory (WM) training remain a matter of debate, especially in older adults. We used functional magnetic resonance imaging (fMRI) together with an n-back task to measure brain plasticity in healthy middle-aged adults following an 8-week adaptive online verbal WM training. Participants performed 32 sessions of this training on their personal computers. In addition, we assessed direct effects of the training by applying a verbal WM task before and after the training. Participants (mean age 55.85 ± 4.24 years) were pseudo-randomly assigned to the experimental group (n = 30) or an active control group (n = 27). Training resulted in an activity decrease in regions known to be involved in verbal WM (i.e., fronto-parieto-cerebellar circuitry and subcortical regions), indicating that the brain became potentially more efficient after the training. These activation decreases were associated with a significant performance improvement in the n-back task inside the scanner reflecting considerable practice effects. In addition, there were training-associated direct effects in the additional, external verbal WM task (i.e., HAWIE-R digit span forward task), and indicating that the training generally improved performance in this cognitive domain. These results led us to conclude that even at advanced age cognitive training can improve WM capacity and increase neural efficiency in specific regions or networks.

A randomized controlled trial of working memory and processing speed training in schizophrenia

BACKGROUND

Although prior research has shown that cognitive training may improve cognition for schizophrenia patients, it is currently unclear which domains of cognition should be targeted in training. One suggestion is to target low- or mid-level cognitive processes. In particular, working memory (WM) and processing speed (PS) have been named as two key areas of impairment in schizophrenia, and two domains of cognition that are linked to higher-order cognition and daily functioning. This study aimed to investigate the near-transfer (transfer of gains to related contexts), far-transfer (transfer of gains to unrelated contexts), and real-world gains associated with WM and PS training in schizophrenia.

METHODS

Eighty-three participants with schizophrenia were recruited and randomly assigned to computerized WM training, PS training, or a no-training control group. Outcome measures included WM, PS, fluid intelligence, executive functioning, social cognition, and daily functioning and symptoms.

RESULTS

PS training led to significant gains in untrained PS tasks, as well as gains in far-transfer tasks that required speed of processing. WM training did not lead to gains in untrained WM tasks and showed inconsistent effects on some far-transfer tasks.

CONCLUSIONS

These results suggest some benefit of domain-specific cognitive training, specifically PS training, in schizophrenia. Far-transfer of gains to other cognitive domains and to real-world functioning may not occur after targeted WM or PS training, though non-specific effects (e.g. through behavioral activation, increased motivation) may lead to improvements in some tasks. Future studies should continue to investigate the mechanisms by which cognitive training may enhance cognition and functioning in schizophrenia.

The efficacy of a training that combines activities on working memory and metacognition: Transfer and maintenance effects in children with ADHD and typical development

Introduction: It has been demonstrated that children with attention deficit and hyperactivity disorder (ADHD) have impairments in working memory (WM), and particularly its visuospatial component, responsible for academic underachievement. Furthermore, children with ADHD have difficulty in metacognition, and consequently use inappropriate strategies to control attention and impulsive behavior. The aim of the present study was to devise a training that combined individual exercises on visuospatial WM and group metacognitive activities capable of helping children with ADHD to ameliorate their performance in executive functioning tasks, and to contain their inattentive and hyperactive/impulsive behavior. Method: A combined training that focused on visuospatial WM and metacognition was administered to 12 children with a diagnosis of ADHD and 15 typically-developing children. Tasks on executive functions and questionnaires for parents and teachers were administered before and at the end of the training, and one month after the post-test. Specific short- and long-term training gains and transfer effects were examined. Effects of the training on parents' and teachers' ratings were also considered. Results: Specific gains and transfer effects were found at the post-test and long-term assessments in both typically-developing children and those with ADHD. Parents' and teachers' ratings also indicated an improvement in the symptomatic behavior of children with ADHD. Conclusion: The results of this study have clinical and educational implications. A training that combines individual computerized visuospatial WM activities with metacognitive group reflection about useful strategies seems to produce promising results, helping children with ADHD to improve their executive functioning and behavioral problems.

The academic outcomes of working memory and metacognitive strategy training in children: A double-blind randomized controlled trial

Working memory training has been shown to improve performance on untrained working memory tasks in typically developing children, at least when compared to non‐adaptive training; however, there is little evidence that it improves academic outcomes. The lack of transfer to academic outcomes may be because children are only learning skills and strategies in a very narrow context, which they are unable to apply to other tasks. Metacognitive strategy interventions, which promote metacognitive awareness and teach children general strategies that can be used on a variety of tasks, may be a crucial missing link in this regard. In this double‐blind randomized controlled trial, 95 typically developing children aged 9–14 years were allocated to three cognitive training programmes that were conducted daily after‐school. One group received Cogmed working memory training, another group received concurrent Cogmed and metacognitive strategy training, and the control group received adaptive visual search training, which better controls for expectancy and motivation than non‐adaptive training. Children were assessed on four working memory tasks, reading comprehension, and mathematical reasoning before, immediately after, and 3 months after training. Working memory training improved working memory and mathematical reasoning relative to the control group. The improvements in working memory were maintained 3 months later, and these were significantly greater for the group that received metacognitive strategy training, compared to working memory training alone. Working memory training is a potentially effective educational intervention when provided in addition to school; however, future research will need to investigate ways to maintain academic improvements long term and to optimize metacognitive strategy training to promote far‐transfer. A video abstract of this article can be viewed at https://youtu.be/-7MML48ZFgw

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.

Working Memory Training in Professional Football Players: A Small-Scale Descriptive Feasibility Study-The Importance of Personality, Psychological Well-Being, and Motivational Factors

Background: Working memory training (WMT) programs can improve working memory (WM). In football players, this could lead to improved performance on the pitch. Method: Eighteen professional football players of Maatschappelijke Voetbal Vereniging Maastricht (MVV) participated and followed an online, computerized WMT program. Neuropsychological performance, psychological wellbeing, self-efficacy, and football skills (Loughborough Soccer Passing Test; LSPT) were assessed at three time points, before and after WMT and at three-month follow-up. Descriptive data are reported. Results: Baseline characteristics were roughly similar for both groups. Participants performed better on the trained WM tasks, but performance for other neuropsychological test measures or the LSPT did not change. Low compliance rates were observed, showing differences in personality and well-being between compliers and non-compliers. Conclusions: WMT is not a feasible and effective strategy to improve non-trained cognitive measures and football performance. However, this study indicates that it is important to take individual characteristics into account.

Training Working Memory of Children with and without Dyslexia

For the future school performance of a child in the fields of literacy and numeracy, the operational efficiency of working memory is a central predictor. Children affected by dyslexia exhibit specific deficits in the functions of working memory. A software application for elementary school-age children has been specifically developed for this study, attempting to improve the working memory's operational efficiency. Based on Baddeley's model of working memory (1986), the phonological loop, the visuo-spatial sketchpad, and the central executive were trained in 18 sessions over a period of six weeks. The group of test subjects undergoing this training was composed of third-graders, of which 43 were and 27 were not affected by dyslexia. The untrained control group was made up of 41 third-graders with dyslexia and 28 without dyslexia. While the short-term effects of the program could not be proven, the present analyses focus on long-term effects. The results obtained from a pre-test/follow-up design reveal that no long-term increases in performance regarding phonological and central executive working memory could be confirmed. Only the visuo-spatial Corsi block span exhibited a training effect over a period of three months. Additionally, training did not show any long-term effect of performance improvement, not even for a subgroup of children with dyslexia and an especially low working memory performance. Thus, even after this study, the question whether working memory can be trained or not remains partly unanswered but leaves us predominantly pessimistic.

The Effects of Transcranial Direct Current Stimulation (tDCS) on Working Memory Training in Healthy Young Adults

Working memory (WM) is a fundamental cognitive ability to support complex thought, but it is limited in capacity. WM training has shown the potential benefit for those in need of a higher WM ability. Many studies have shown the potential of transcranial direct current stimulation (tDCS) to transiently enhance WM performance by delivering a low current to the brain cortex of interest, via electrodes on the scalp. tDCS has also been revealed as a promising intervention to augment WM training in a few studies. However, those few tDCS-paired WM training studies, focused more on the effect of tDCS on WM enhancement and its transferability after training and paid less attention to the variation of cognitive performance during the training procedure. The current study attempted to explore the effect of tDCS on the variation of performance, during WM training, in healthy young adults. All the participants received WM training with the load-adaptive verbal N-back task, for 5 days. During the training procedure, active/sham anodal high-definition tDCS (HD-tDCS) was used to stimulate the left dorsolateral prefrontal cortex (DLPFC). To examine the training effect, pre- and post-tests were performed, respectively, 1 day before and after the training sessions. At the beginning of each training session, stable-load WM tasks were performed, to examine the performance variation during training. Compared to the sham stimulation, higher learning rates of performance metrics during the training procedure were found when WM training was combined with active anodal HD-tDCS. The performance improvements (post–pre) of the active group, were also found to be higher than those of the sham group and were transferred to a similar untrained WM task. Further analysis revealed a negative relationship between the training improvements and the baseline performance. These findings show the potential that tDCS may be leveraged as an intervention to facilitate WM training, for those in need of a higher WM ability.

N-back training and transfer effects revealed by behavioral responses and EEG

INTRODUCTION

Cognitive function performance decreases in older individuals compared to young adults. To curb this decline, cognitive training is applied, but it is not clear whether it improves only the trained task or also other cognitive functions. To investigate this, we considered an N-back working memory (WM) training task and verified whether it improves both trained WM and untrained cognitive functions.

METHODS

As EEG studies have noted task difficulty and age-related changes in time-locked EEG responses, called event-related potentials (ERPs), we focused on the relation between the P300 ERP component, task difficulty level, and behavior response accuracy and reaction time (RT) in young and older healthy adults. We used two groups of young and older healthy participants to assess the effect of N-back training: cognitive training group (CTG) and passive control group (PCG). Before and after training, cognitive tests were administered to both groups to evaluate transfer effects.

RESULTS

Despite the observed age-related differences in the P300 ERP component and in terms of RT and accuracy, our findings demonstrate a stronger improvement in the trained task for older CTGs compared to younger CTGs, larger near- and far-transfer effect to WM and fluid intelligence for both younger and older CTGs, and a far-transfer effect to attention but only for older adults. Significant differences in response accuracy were shown between young and older subjects in spatial memory and attention tests.

CONCLUSION

The application of a WM training is a promising tool for both healthy adults, and in particular for older subjects, as it showed physiological and behavioral differences in cognitive plasticity across life span and evidence of benefits in the trained task and near-/far-transfer effects to other cognitive functions.

WOME: Theory-Based Working Memory Training - A Placebo-Controlled, Double-Blind Evaluation in Older Adults

Background: Scientifically evaluated cognitive intervention programs are essential to meet the demands of our increasingly aging society. Currently, one of the “hottest” topics in the field is the improvement of working memory function and its potential impact on overall cognition. The present study evaluated the efficacy of WOME (WOrking MEmory), a theory-based working memory training program, in a double-blind, placebo-controlled, and randomized controlled trial (www.drks.de, DRKS00013162).

Methods:N = 60 healthy older adults were allocated to (1) the WOME intervention, (2) an active low-level intervention, or (3) a passive control group. Overall, the intervention groups practiced twelve sessions of 45 min within 4 weeks of their respective training. Transfer effects were measured via an extensive battery of neuropsychological tests and questionnaires both pre-/post-training and at a 3-month follow-up.

Results:WOME led to a significant improvement in working memory function, demonstrated on a non-trained near transfer task and on two different composite scores with moderate to large effect sizes. In addition, we found some indication of relevant impact on everyday life. The effects were short-term rather than stable, being substantially diminished at follow-up with only little evidence suggesting long-term maintenance. No transfer effects on other cognitive functions were observed.

Conclusion:WOME is an appropriate and efficient intervention specifically targeting the working memory system in healthy older adults.

Trial Registration: German Clinical Trials Register (DRKS), Identifier: DRKS00013162.

Exploring N-Back Cognitive Training for Children With ADHD

Objective: The efficacy of n-back training for children with attention deficit hyperactivity disorder (ADHD) was tested in a randomized controlled trial. Method: 41 children aged 7 to 14 years with ADHD were trained on an n-back task, and their performance was compared with that of an active control group (n = 39) who were trained on a general knowledge and vocabulary task. Results: The experimental group demonstrated transfer of training to a nontrained n-back task as well as to a measure of inhibitory control. These effects were correlated with the magnitude of training gains. Conclusion: Our results suggest that n-back training may be useful in addressing some of the cognitive and behavioral issues associated with ADHD.

Computer-Based Training in Math and Working Memory Improves Cognitive Skills and Academic Achievement in Primary School Children: Behavioral Results

Student academic achievement has been positively related to further development outcomes, such as the attainment of higher educational, employment, and socioeconomic aspirations. Among all the academic competences, mathematics has been identified as an essential skill in the field of international leadership as well as for those seeking positions in disciplines related to science, technology, and engineering. Given its positive consequences, studies have designed trainings to enhance children's mathematical skills. Additionally, the ability to regulate and control actions and cognitions, i.e., executive functions (EF), has been associated with school success, which has resulted in a strong effort to develop EF training programs to improve students' EF and academic achievement. The present study examined the efficacy of a school computer-based training composed of two components, namely, working memory and mathematics tasks. Among the advantages of using a computer-based training program is the ease with which it can be implemented in school settings and the ease by which the difficulty of the tasks can be adapted to fit the child's ability level. To test the effects of the training, children's cognitive skills (EF and IQ) and their school achievement (math and language grades and abilities) were evaluated. The results revealed a significant improvement in cognitive skills, such as non-verbal IQ and inhibition, and better school performance in math and reading among the children who participated in the training compared to those children who did not. Most of the improvements were related to training on WM tasks. These findings confirmed the efficacy of a computer-based training that combined WM and mathematics activities as part of the school routines based on the training's impact on children's academic competences and cognitive skills.

Cogmed Working Memory Training Presents Unique Implementation Challenges in Adults With ADHD

Cogmed Working Memory Training (CWMT), an online cognitive training program developed for children, is an increasingly popular non-pharmacological intervention for ADHD amongst all ages, despite limited supporting evidence. The initial objective of the present work was to examine the short- and long-term impacts of CWMT on brain function in adults with ADHD. However, during the conduct of our study, we experienced multiple levels of failures in recruitment and retention that signaled potential concerns about the suitability of CWMT for adults with ADHD. This perspective piece aims to describe the difficulties we encountered in the context of studies examining the efficacy of CWMT in comparable populations. We trace these difficulties to the limited tolerability of the current CWMT structure for adults with ADHD, and review similar limitations in the literature. We suggest that efficacy of CWMT in children may be due in large part to close monitoring and scaffolding provided by clinicians and caregivers. For CWMT to have viability for widespread use in adults, greater support and structure will be needed for users to improve the likelihood of adherence. We discuss implications and considerations for future efforts in both research and clinical practice.

Disseminability of computerized cognitive training: Performance across coaches

Cogmed is a computerized cognitive intervention utilizing coaches who receive standardized instruction in analyzing training indices and tailoring feedback to remotely monitor participant's performance. The goal of this study was to examine adherence, satisfaction, and efficacy of Cogmed across coaches. Survivors of pediatric brain tumors and acute lymphoblastic leukemia (N = 68) were randomized to intervention (Cogmed) or waitlist control. The intervention group was matched with one of two coaches. Cognitive assessments were completed before and after intervention, and participants and caregivers in the intervention group completed satisfaction surveys. T-tests showed no differences in adherence across coaches (number of sessions completed p = .38; d = .32). Noninferiority statistics were not consistently equivalent for satisfaction, but equivalence was supported for caregiver perceptions of pragmatic utility and participant perceptions of logistical ease of Cogmed. Equivalence was not consistently suggested for cognitive outcomes, but was supported on measures tapping relevant cognitive domains (attention, working memory, processing speed, academic fluency). This study suggests adherence can be maintained across coaches. While aspects of satisfaction and cognitive outcomes were equivalent, the possible influence of coach-based variables cannot be ruled out. Findings highlight challenges in standardizing the coaching component of multicomponent computerized interventions and the need for ongoing research to establish dessiminability.

The Role of Working Memory for Cognitive Control in Anorexia Nervosa versus Substance Use Disorder

Prefrontal cortex executive functions, such as working memory (WM) interact with limbic processes to foster impulse control. Such an interaction is referred to in a growing body of publications by terms such as cognitive control, cognitive inhibition, affect regulation, self-regulation, top-down control, and cognitive–emotion interaction. The rising trend of research into cognitive control of impulsivity, using various related terms reflects the importance of research into impulse control, as failure to employ cognitions optimally may eventually result in mental disorder. Against this background, we take a novel approach using an impulse control spectrum model – where anorexia nervosa (AN) and substance use disorder (SUD) are at opposite extremes – to examine the role of WM for cognitive control. With this aim, we first summarize WM processes in the healthy brain in order to frame a systematic review of the neuropsychological, neural and genetic findings of AN and SUD. In our systematic review of WM/cognitive control, we found n = 15 studies of AN with a total of n = 582 AN and n = 365 HC participants; and n = 93 studies of SUD with n = 9106 SUD and n = 3028 HC participants. In particular, we consider how WM load/capacity may support the neural process of excessive epistemic foraging (cognitive sampling of the environment to test predictions about the world) in AN that reduces distraction from salient stimuli. We also consider the link between WM and cognitive control in people with SUD who are prone to ‘jumping to conclusions’ and reduced epistemic foraging. Finally, in light of our review, we consider WM training as a novel research tool and an adjunct to enhance treatment that improves cognitive control of impulsivity.

The efficacy of a working memory training in substance use patients: A randomized double-blind placebo-controlled clinical trial

INTRODUCTION

Substance use disorder patients show impairments in working memory (WM) functioning. Previous findings indicate that a WM training results in improvements of working memory capacity (WMC) and in decreased clinical symptoms in a range of mental disorders, including alcohol use disorder.

METHOD

The aim of the current study is to investigate the efficacy of a 24-session WM training in addition to treatment as usual on craving, WMC, substance use, impulsivity, attention bias, and psychopathology using a randomized double-blind placebo-controlled trial. Inpatients (n = 180) diagnosed with an alcohol, cocaine, or cannabis use disorder were included.

RESULTS

Although the WM training resulted in better scores on the trained tasks in both groups, the placebo training resulted in a better or equal WMC compared to the experimental training, as measured with two nontrained transfer tasks. The WM training had no effect on craving, substance use, impulsivity, attention bias, and psychopathology.

CONCLUSION

Overall, we did not find evidence for the efficacy of WM training on WMC or clinical symptoms as compared to a placebo training in a population of substance use disorder patients. Future research needs to investigate further whether WMC is an important factor that is associated with substance-abuse-related behavior, and whether working memory training could be useful in substance use disorders.

Working Memory Training in ADHD: Controlling for Engagement, Motivation, and Expectancy of Improvement (Pilot Study)

OBJECTIVE

The aim of this study was to evaluate whether a shortened-length session of CogMed Working Memory Training (CWMT) would be a suitable active control group and evaluate study protocol to aid in design refinements for a larger randomized controlled trial (RCT).

METHOD

Thirty-eight post-secondary students diagnosed with ADHD were randomized into 25 sessions of standard (45 min/session) or shortened (15 min/session) CWMT, or into a waitlist control group.

RESULTS

There was no significant difference in completion rate or training index score between the standard- and shortened-length groups indicating that both groups showed improvement and put forth good effort during training.

CONCLUSION

Preliminary findings suggest that shorter training sessions may induce similar levels of engagement, motivation, and expectancy of improvement in participants. We conclude that a larger scale RCT that utilizes shortened-length training as an active control group is warranted, but that a few modifications to the study protocol will be required.

A double-blind randomized pilot trial comparing computerized cognitive exercises to Tetris in adolescents with attention-deficit/hyperactivity disorder

BACKGROUND

The purpose of this trial was to examine the feasibility and efficacy of computerized cognitive exercises from Scientific Brain Training (SBT), compared to the computer game Tetris as an active placebo, in a pilot study of adolescents with attention-deficit/hyperactivity disorder (ADHD).

METHOD

Eighteen adolescents with ADHD were randomized to treatment or control intervention for 7 weeks. Outcome measures were cognitive test, symptom, and motivation questionnaires.

RESULTS

SBT and Tetris were feasible as home-based interventions, and participants' compliance was high, but participants perceived both interventions as not very interesting or helpful. There were no significant group differences on cognitive and ADHD-symptom measures after intervention. Pre-post intra-group measurement showed that the SBT had a significant beneficial effect on sustained attention, while the active placebo had significant beneficial effects on working memory, both with large effect sizes.

CONCLUSION

Although no significant differences were found between groups on any measure, there were significant intra-group changes for each group.

The Benefits of Working Memory Capacity on Attentional Control under Pressure

The present study aimed to examine the effects of working memory capacity (WMC) and state anxiety (SA) on attentional control. WMC was manipulated by (a) dividing participants into low- and high-WMC groups (Experiment 1), and (b) using working memory training to improve WMC (Experiment 2). SA was manipulated by creating low- and high-SA conditions. Attentional control was evaluated by using antisaccade task. Results demonstrated that (a) higher WMC indicated better attentional control (Experiments 1 and 2); (b) the effects of SA on attentional control were inconsistent because SA impaired attentional control in Experiment 1, but favored attentional control in Experiment 2; and (c) the interaction of SA and WMC was not significant (Experiments 1 and 2). This study directly manipulated WMC by working memory training, which provided more reliable evidence for controlled attention view of WMC and new supportive evidence for working memory training (i.e., far transfer effect on attentional control). And the refinement of the relationship between anxiety and attentional control proposed by Attentional Control Theory was also discussed.

Transcranial Electric Stimulation Can Impair Gains during Working Memory Training and Affects the Resting State Connectivity

Transcranial electric stimulation (tES) is a promising technique that has been shown to improve working memory (WM) performance and enhance the effect of cognitive training. However, experimental set up and electrode placement are not always determined based on neurofunctional knowledge about WM, leading to inconsistent results. Additional research on the effects of tES grounded on neurofunctional evidence is therefore necessary. Sixty young, healthy, volunteers, assigned to six different groups, participated in 5 days of stimulation or sham treatment. Twenty-five of these subjects also participated in MRI acquisition. We performed three experiments: In the first one, we evaluated tES using either direct current stimulation (tDCS) with bilateral stimulation of the frontal or parietal lobe; in the second one, we used the same tDCS protocol with a different electrode placement (i.e., supraorbital cathode); in the third one, we used alternating currents (tACS) of 35 Hz, applied bilaterally to either the frontal or parietal lobes. The behavioral outcome measure was the WM capacity (i.e., number of remembered spatial position) during the 5 days of training. In a subsample of subjects we evaluated the neural effects of tDCS by measuring resting state connectivity with functional MRI, before and after the 5 days of tDCS and visuo-spatial WM training. We found a significant impairment of WM training-related gains associated with parietal tACS and frontal tDCS. Five days of tDCS stimulation was also associated with significant change in resting state connectivity revealed by multivariate pattern analysis. None of the stimulation paradigms resulted in improved WM performance or enhanced WM training gains. These results show that tES can have negative effects on cognitive plasticity and affect resting-state functional connectivity.

Direct-Current Stimulation Does Little to Improve the Outcome of Working Memory Training in Older Adults

The promise of transcranial direct-current stimulation (tDCS) as a modulator of cognition has appealed to researchers, media, and the general public. Researchers have suggested that tDCS may increase effects of cognitive training. In this study of 123 older adults, we examined the interactive effects of 20 sessions of anodal tDCS over the left prefrontal cortex (vs. sham tDCS) and simultaneous working memory training (vs. control training) on change in cognitive abilities. Stimulation did not modulate gains from pre- to posttest on latent factors of either trained or untrained tasks in a statistically significant manner. A supporting meta-analysis ( n = 266), including younger as well as older individuals, showed that, when combined with training, tDCS was not much more effective than sham tDCS at changing working memory performance ( g = 0.07, 95% confidence interval, or CI = [-0.21, 0.34]) and global cognition performance ( g = -0.01, 95% CI = [-0.29, 0.26]) assessed in the absence of stimulation. These results question the general usefulness of current tDCS protocols for enhancing the effects of cognitive training on cognitive ability.

Working Memory Training for Healthy Older Adults: The Role of Individual Characteristics in Explaining Short- and Long-Term Gains

Objective: The aim of the present study was to explore whether individual characteristics such as age, education, vocabulary, and baseline performance in a working memory (WM) task-similar to the one used in the training (criterion task)-predict the short- and long-term specific gains and transfer effects of a verbal WM training for older adults. Method: Four studies that adopted the Borella et al. (2010) verbal WM training procedure were found eligible for our analysis as they included: healthy older adults who attended either the training sessions (WM training group), or alternative activities (active control group); the same measures for assessing specific gains (on the criterion WM task), and transfer effects (nearest on a visuo-spatial WM task, near on short-term memory tasks and far on a measure of fluid intelligence, a measure of processing speed and two inhibitory measures); and a follow-up session. Results: Linear mixed models confirmed the overall efficacy of the training, in the short-term at least, and some maintenance effects. In the trained group, the individual characteristics considered were found to contribute (albeit only modestly in some cases) to explaining the effects of the training. Conclusions: Overall, our findings suggest the importance of taking individual characteristics and individual differences into account when examining WM training gains in older adults.

How Is Working Memory Training Likely to Influence Academic Performance? Current Evidence and Methodological Considerations

Working memory (WM) is one of our core cognitive functions, allowing us to keep information in mind for shorter periods of time and then work with this information. It is the gateway that information has to pass in order to be processed consciously. A well-functioning WM is therefore crucial for a number of everyday activities including learning and academic performance (Gathercole et al., 2003; Bull et al., 2008), which is the focus of this review. Specifically, we will review the research investigating whether improving WM capacity using Cogmed WM training can lead to improvements on academic performance. Emphasis is given to reviewing the theoretical principles upon which such investigations rely, in particular the complex relation between WM and mathematical and reading abilities during development and how these are likely to be influenced by training. We suggest two possible routes in which training can influence academic performance, one through an effect on learning capacity which would thus be evident with time and education, and one through an immediate effect on performance on reading and mathematical tasks. Based on the theoretical complexity described we highlight some methodological issues that are important to take into consideration when designing and interpreting research on WM training and academic performance, but that are nonetheless often overlooked in the current research literature. Finally, we will provide some suggestions for future research for advancing the understanding of WM training and its potential role in supporting academic attainment.