Functional brain changes associated with cognitive training in healthy older adults: A preliminary ALE meta-analysis

Cognitive training and promoting a healthy lifestyle for individuals with isolated REM sleep behavior disorder: study protocol of the delayed-start randomized controlled trial CogTrAiL-RBD

BACKGROUND

Isolated REM sleep behavior disorder (iRBD) is an early α-synucleinopathy often accompanied by incipient cognitive impairment. As executive dysfunctions predict earlier phenotypic conversion from iRBD to Parkinson's disease and Lewy body dementia, cognitive training focusing on executive functions could have disease-modifying effects for individuals with iRBD.

METHODS

The study CogTrAiL-RBD investigates the short- and long-term effectiveness and the feasibility and underlying neural mechanisms of a cognitive training intervention for individuals with iRBD. The intervention consists of a 5-week digital cognitive training accompanied by a module promoting a healthy, active lifestyle. In this monocentric, single-blinded, delayed-start randomized controlled trial, the intervention's effectiveness will be evaluated compared to an initially passive control group that receives the intervention in the second, open-label phase of the study. Eighty individuals with iRBD confirmed by polysomnography will be consecutively recruited from the continuously expanding iRBD cohort at the University Hospital Cologne. The evaluation will focus on cognition and additional neuropsychological and motor variables. Furthermore, the study will examine the feasibility of the intervention, effects on physical activity assessed by accelerometry, and interrogate the intervention's neural effects using magnetic resonance imaging and polysomnography. Besides, a healthy, age-matched control group (HC) will be examined at the first assessment time point, enabling a cross-sectional comparison between individuals with iRBD and HC.

DISCUSSION

This study will provide insights into whether cognitive training and psychoeducation on a healthy, active lifestyle have short- and long-term (neuro-)protective effects for individuals with iRBD.

TRIAL REGISTRATION

The study was prospectively registered in the German Clinical Trial Register (DRKS00024898) on 2022-03-11, https://drks.de/search/de/trial/DRKS00024898 .

PROTOCOL VERSION

V5 2023-04-24.

Positive affect disrupts neurodegeneration effects on cognitive training plasticity in older adults

Cognitive training for older adults varies in efficacy, but it is unclear why some older adults benefit more than others. Positive affective experience (PAE), referring to high positive valence and/or stable arousal states across everyday scenarios, and associated functional networks can protect plasticity mechanisms against Alzheimer's disease neurodegeneration, which may contribute to training outcome variability. The objective of this study is to investigate whether PAE explains variability in cognitive training outcomes by disrupting the adverse effect of neurodegeneration on plasticity. The study's design is a secondary analysis of a randomized control trial of cognitive training with concurrent real or sham brain stimulation (39 older adults with mild cognitive impairment; mean age, 71). Moderation analyses, with change in episodic memory or executive function as the outcome, PAE or baseline resting-state connectivity as the moderator and baseline neurodegeneration as the predictor are the methods used in the study. The result of the study is that PAE stability and baseline default mode network (DMN) connectivity disrupted the effect of neurodegeneration on plasticity in executive function but not episodic memory. The study concludes that PAE stability and degree of DMN integrity both explained cognitive training outcome variability, by reducing the adverse effect of neurodegeneration on cognitive plasticity. We highlight the need to account for PAE, brain aging factors and their interactions with plasticity in cognitive training.

Social perception in deaf individuals: A meta-analysis of neuroimaging studies

Deaf individuals may report difficulties in social interactions. However, whether these difficulties depend on deafness affecting social brain circuits is controversial. Here, we report the first meta-analysis comparing brain activations of hearing and (prelingually) deaf individuals during social perception. Our findings showed that deafness does not impact on the functional mechanisms supporting social perception. Indeed, both deaf and hearing control participants recruited regions of the action observation network during performance of different social tasks employing visual stimuli, and including biological motion perception, face identification, action observation, viewing, identification and memory for signs and lip reading. Moreover, we found increased recruitment of the superior-middle temporal cortex in deaf individuals compared with hearing participants, suggesting a preserved and augmented function during social communication based on signs and lip movements. Overall, our meta-analysis suggests that social difficulties experienced by deaf individuals are unlikely to be associated with brain alterations but may rather depend on non-supportive environments.

The joint effect and hemodynamic mechanism of PA and PM2.5 exposure on cognitive function: A randomized controlled trial study

BACKGROUND

While PM2.5 has been shown to impair cognitive function, physical activity (PA) is known to enhance it. Nonetheless, considering the increased inhalation of PM2.5 during exercise, the potential of PA to counteract the detrimental effects of PM2.5, along with the underlying hemodynamic mechanisms, remains uncertain.

METHODS

We conducted a double-blinded, randomized controlled trial among healthy young adults in Beijing, China. Ninety-three participants were randomly allocated to groups experiencing different intensities of PA interventions, and either subjected to purified or unpurified air conditions. Cognitive function was measured by the Color-Word Matching Stroop task, and the hemodynamic response was measured using functional near-infrared spectroscopy during participants performed the Stroop task both before and after the intervention. Linear mixed-effect models were used to estimate the impact of PA and PM2.5 on cognitive function and hemodynamic response.

RESULTS

The reaction time for congruent and incongruent Stroop tasks improved by - 80.714 (95% CI: -136.733, -24.695) and - 105.843 (95% CI: -188.6, -23.085) milliseconds after high-intensity interval training (HIIT) intervention. PM2.5 and HIIT had interaction effects on cognition, such that every 1 μg/m3 increase in PM2.5 attenuated the benefits of HIIT on reaction time by 2.231 (95% CI: 0.523, 3.938) and 3.305 (95% CI: 0.791, 5.819) milliseconds for congruent and incongruent Stroop tasks. Moreover, we divided participants into high and low PM2.5 exposure groups based on average PM2.5 concentration (32.980 μg/m3), and found that HIIT intervention in high PM2.5 concentration led to 69.897 (95% CI: 9.317, 130.476) and 99.269 (95% CI: 10.054, 188.485) milliseconds increased in the reaction time of congruent and incongruent Stroop, compared with the control group among low PM2.5. Furthermore, we found a significant interaction effects of PM2.5 and moderate-intensity continuous training (MICT) on the middle frontal gyrus (MFG) and dorsolateral superior frontal gyrus (DLPFC). PM2.5 and HIIT had a significant interaction effect on the DLPFC.

CONCLUSIONS

HIIT improved cognitive function, but the cognitive benefits of HIIT were attenuated or even reversed under high PM2.5 exposure. The activation of the DLPFC and MFG could serve as hemodynamic mechanisms to explain the joint effect of PA and PM2.5.

Effects of Cognitive Training on Alzheimer's Disease and Related Dementias: The Moderating Role of Social Determinants of Health

Objective: We examined whether social determinants of health (SDoH) are associated with Alzheimer's disease and related dementias (ADRD) risk and the effects of cognitive training over a 20-year follow-up period. Methods: Data were obtained from 1605 participants in ACTIVE. SDoH measures were created using baseline data at the individual and neighborhood level. Incident ADRD was defined using administrative claims data (1999-2019). Cause-specific hazard models estimated associations between SDoH and claims-based diagnosed ADRD. Results: Higher scores on neighborhood and built environment were associated with lower ADRD risk. Trained participants obtained a greater degree of protection from ADRD when they had higher scores for SDoH domains associated with health care and education access. However, there were fewer significant SDoH moderation effects on cognitive training than expected. Discussion: Future work should continue to explore culturally tailored cognitive training interventions to reduce ADRD risk associated with SDoH that disproportionately affects racially diverse aging populations.

Cognitive functions and sense of coherence in patients with carotid artery stenosis-Preliminary report

Background

There is scarcely any data in the available literature on the relationship between sense of coherence (SOC) and cognitive functioning, and no information on the relationship between SOC and cognitive parameters in patients with carotid atherosclerosis.

Aim

The aim of this paper was to determine the relationship of SOC measured prior to carotid artery stenting (CAS) with neurocognitive functioning in patients with carotid atherosclerosis 12 months after CAS.

Methods

A total of 35 patients with carotid atherosclerosis completed the SOC-29 Orientation to Life Questionnaire (SOC-29) and completed a cognitive test battery twice, i.e., before (baseline-T1) and 12 months after stent implantation (follow-up-T2). Selected cognitive functions such as memory, attention, perception, visuospatial and executive functions and non-verbal fluency were assessed.

Results

One year after the procedure, patients with a higher SOC and sense of manageability present better performance in visual memory. Higher SOC and sense of meaningfulness are positively related to the speed of understanding the changing rules of card sorting (WCST).

Conclusion

Higher overall SOC and a component of sense of meaningfulness and manageability may be related to better cognitive functioning 1 year after the procedure.

Alpha and Low Gamma Embedded With White Noise Binaural Beats Modulating Working Memory among Malaysian Young Adult: A Preliminary fMRI Study

Introduction: Binaural beats (BB) provisions alpha and gamma have been suggested to modulate working memory (WM), while white noise (WN) acted as a control condition. Methods: The current study overlays WN on alpha and gamma tones to study its modulating role on WM performance. A block-design n-back task paradigm used to determine the effect of load on embedded BB on WM performance using functional magnetic resonance imaging. Results: Six young adults (3 males and 3 females) with mean age of 23.5 ± 0.84 within the Kota Bharu vicinity participated in the study. A repeated-measures ANOVA (p<0.05) on response accuracy indicate medium effect size on condition (η2 =0.420), and large effect sizes on groups (η2 = 0.388) and load (η2 = 0.487). The potential practical difference is more evident on low- (0-back) and high-load (3-back). GWN provision marginally excels, implying its entrainment may benefit WM processing. A repeated-measures ANOVA (p<0.05) on reaction time (RT) implied a large effect size on all variables (condition: η2=0.065, groups: η2=0.227 and load: η2=0.169). It was observed that BB exposure elicits a slow processing speed which worsens RT. The neural correlates suggest activated regions in GWN and AWN are associated with attentional mechanisms and WM processes. Conclusion: Preliminary findings indicate both embedded BB has a potential to improve WM performance with the cost of slower processing speed. GWN provision modulates attentional mechanisms benefiting WM performance and AWN may enhance performance in extreme ends of WM load.

Unifying framework for cognitive training interventions in brain aging

Cognitive training is a promising tool for slowing or preventing cognitive decline in older adults at-risk for dementia. Its success, however, has been limited by a lack of evidence showing that it reliably causes broad training effects: improvements in cognition across a range of domains that lead to real-world benefits. Here, we propose a framework for enhancing the effect of cognitive training interventions in brain aging. The focus is on (A) developing cognitive training task paradigms that are informed by population-level cognitive characteristics and pathophysiology, and (B) personalizing how these sets are presented to participants during training via feedback loops that aim to optimize "mismatch" between participant capacity and training demands using both adaptation and random variability. In this way, cognitive training can better alter whole-brain topology in a manner that supports broad training effects in the context of brain aging.

Hearing voices in the head: Two meta-analyses on structural correlates of auditory hallucinations in schizophrenia

Past voxel-based morphometry (VBM) studies demonstrate reduced grey matter volume (GMV) in schizophrenia (SZ) patients' brains in various cortical and subcortical regions. Probably due to SZ symptoms' heterogeneity, these results are often inconsistent and difficult to integrate. We hypothesized that focusing on auditory verbal hallucinations (AVH) - one of the most common SZ symptoms - would allow reducing heterogeneity and discovering further compelling evidence of SZ neural correlates. We carried out two voxel-based meta-analyses of past studies that investigated the structural correlates of AVH in SZ. The review of whole-brain VBM studies published until June 2022 in PubMed and PsychInfo databases yielded (a) 13 studies on correlations between GMV and AVH severity in SZ patients (n = 472; 86 foci), and (b) 11 studies involving comparisons between hallucinating SZ patients (n = 504) and healthy controls (n = 524; 74 foci). Data were analyzed using the Activation Likelihood Estimation method. AVH severity was associated with decreased GMV in patients' left superior temporal gyrus (STG) and left posterior insula. Compared with healthy controls, hallucinating SZ patients showed reduced GMV on the left anterior insula and left inferior frontal gyrus (IFG). Our findings revealed important structural dysfunctions in a left lateralized cluster of brain regions, including the insula and temporo-frontal regions, that significantly contribute to the severity and persistence of AVH. Structural atrophy found in circuits involved in generating and perceiving speech, as well as in auditory signal processing, might reasonably be considered a biological marker of AVH in SZ.

Strategies to Promote Cognitive Health in Aging: Recent Evidence and Innovations

PURPOSE OF REVIEW

We review recent work on applications of non-pharmacologic strategies to promote cognitive health in older adulthood and discuss potential network mechanisms, limitations, and considerations for improving intervention uptake and efficacy.

RECENT FINDINGS

In healthy older adults and patients with mild cognitive impairment, cognitive training produces global and domain-specific cognitive gains, though effect sizes tend to be modest and transfer is variable. Non-invasive brain stimulation has shown moderate success in enhancing cognitive function, though the optimum approach, parameters, and cortical targets require further investigation. Physical activity improves cognitive functions in late life, with emerging trials highlighting key intervention components that may maximize treatment outcomes. Multimodal interventions may be superior to single-component interventions in conferring cognitive gains, although interpretation is limited by modest sample sizes and variability in training components and parameters. Across modalities, individual differences in patient characteristics predict therapeutic response. These interventions may advance cognitive health by modulating functional networks that support core cognitive abilities including the default mode, executive control, and salience networks. Effectiveness of cognitive enhancement strategies may be increased with clinician-led coaching, booster sessions, gamification, integration of multiple intervention modalities, and concrete applications to everyday functioning. Future trials involving rigorous comparisons of training components, parameters, and delivery formats will be essential in establishing the precise approaches needed to maximize cognitive outcomes. Novel studies using patient-level clinical and neuroimaging features to predict individual differences in training gains may inform the development of personalized intervention prescriptions to optimize cognitive health in late life.

Virtual Reality-based Cognitive Intervention for Enhancing Executive Functions in Community-dwelling Older Adults

With the rapid growth of the older population globally, it is anticipated that age-related cognitive decline in the prodromal phase and more severe pathological decline will increase. Moreover, currently, no effective treatment options for the disease exist. Thus, early and timely prevention actions are promising and prior strategies to preserve cognitive functions by preventing symptomatology from increasing the age-related deterioration of the functions in healthy older adults. This study aims to develop the virtual reality-based cognitive intervention for enhancing executive functions (EFs) and examine the EFs after training with the virtual reality-based cognitive intervention in community-dwelling older adults. Following inclusion/exclusion criteria, 60 community-dwelling older adults aged 60-69 years were involved in the study and randomly divided into passive control and experimental groups. Eight 60 min virtual reality-based cognitive intervention sessions were held twice a week and lasted for 1 month. The EFs (i.e., inhibition, updating, and shifting) of the participants were assessed by using standardized computerized tasks, i.e., Go/NoGo, forward and backward digit span, and Berg's card sorting tasks. Additionally, a repeated-measure ANCOVA and effect sizes were applied to investigate the effects of the developed intervention. The virtual reality-based intervention significantly improved the EFs of older adults in the experimental group. Specifically, the magnitudes of enhancement were observed for inhibitory as indexed by the response time, F(1) = 6.95, p < .05, η_p² = .11, updating as represented by the memory span, F(1) = 12.09, p < .01, η_p² = .18, and the response time, F(1) = 4.46, p = .04, η_p² = .07, and shifting abilities as indexed by the percentage of correct responses, F(1) = 5.30, p = .03, η_p² = .09, respectively. The results indicated that the simultaneous combined cognitive-motor control as embedded in the virtual-based intervention is safe and effective in enhancing EFs in older adults without cognitive impairment. Nevertheless, further studies are required to investigate the benefits of these enhancements to motor functions and emotional aspects relating to daily living and the well-being of older populations in communities.

The effect of creative expression program in neurocognitive networks performance measured by task and resting-state functional MRI

BACKGROUND

The current study examined the effects of a 16-week creative expression program on brain activity during a story creating task and resting-state functional network connectivity in mild cognitive impairment (MCI) adults.

METHOD

Thirty-six MCI adults were allocated to either the creative expression program (CrExp, n = 18) or control group (CG,n = 18). Before and after intervention, all participants were scanned with functional magnetic resonance imaging (fMRI) during story creating task performance and a resting state. The two-group comparison was calculated between the blood oxygenation level-dependent (BOLD) signal changes for each cluster to investigate the differences in fMRI activation and functional connectivity (FC) between two groups.

RESULTS

Task activation analyses showed an increase in the right anterior cingulate gyrus (ACG), right medial frontal gyrus (MFG), right lentiform nucleus (LN), left hippocampus (HIP), left middle occipital gyrus (MOG), and left cerebellum posterior lobe (CPL) (p < 0.05). Story creating performance improvements were associated with greater activation in the left HIP region. Resting-state functional connectivity (FC) between left HIP and certain other brain areas shown a significant interaction of creative expression group versus control group. Moreover, connectivity between the right angular gyrus (ANG), right inferior temporal gyrus (ITG), right superior occipital gyrus (SOG), left ANG, and left MFG were related to improved cognitive performance (p < 0.05).

CONCLUSION

These data extend current knowledge by indicating that the creative expression program can improve cognitive activation in MCI, and these enhancements may be related to the neurocognitive network plasticity changes induced by creative expression training.

Cognitive and hippocampal changes weeks and years after memory training

While immediate effects of memory-training are widely reported in young and older adults, less is known regarding training-dependent hippocampal plasticity across multiple intervention phases, and long-term maintenance of such. Here, 157 healthy young and older adults underwent a training-intervention including two 10 weeks periods of episodic-memory training, separated by two 2 weeks periods of no training. Both age groups showed improvements on a criterion task, which prevailed after 3 years. When compared to the reference condition of no training, relative increases in hippocampal volume were observed after the training across age groups, which were maintained after 10 weeks periods of no training. However, there was age-group dependent temporal variation with respect to timing of effects. Hippocampal volume of the training group did not differ from that of a passive control-group 3 years after the intervention. The young showed an immediate near-transfer effect on a word-association task. We show that training-gains on memory performance can prevail for at least 3 years. Memory training can induce increases in hippocampal volume immediately after the intervention and after months. Episodic-memory training can produce transfer effects to a non-trained memory task in young adults. However, maintained effects on hippocampal volume beyond 10 weeks are uncertain, and likely require continuous training.

A Conceptual View of Cognitive Intervention in Older Adults With and Without Cognitive Decline-A Systemic Review

Background: Dementia is the one of the most common and prominent disease in the elderly person that results in the Cognitive interventions. In this study, we aim to conceptualize the cognitive intervention for older adults with and without cognitive dysfunction and to clarify the heterogeneity existing in this literature field by determining the main variables implicated. Methods: We conducted a study analysis using previous literature highlighting the significant data reporting empirical results from cognitive intervention for healthy older adults and other seniors with different types of dementia. Each paper was reviewed in terms of compensatory cognitive training, cognitive remediation, enrichment, cognitive activation, brain training, cognitive stimulation, cognitive training, and cognitive rehabilitation. The research analysis was performed following rigorous inclusion and exclusion criteria with the purpose of collecting relevant answers to our research questions. Results: We included a total of 168 studies in our review. Our findings indicated heterogeneity regarding methods, concepts, and procedures. Additionally, the values were integrated using different information existing in this field. Conclusion: In conclusion, we highlighted that this is the first review that clarify the discrepancy of various existing definitions, methods, and procedures, as well as the overlapping information in the cognitive interventions.

A meta-analysis on neural changes of cognitive training for mental disorders in executive function tasks: increase or decrease brain activation?

BACKGROUND

Cognitive impairment is often found in patients with psychiatric disorders, and cognitive training (CT) has been shown to help these patients. To better understand the mechanisms of CT, many neuroimaging studies have investigated the neural changes associated with it. However, the results of those studies have been inconsistent, making it difficult to draw conclusions from the literature. Therefore, the objective of this meta-analysis was to identify consistent patterns in the literature of neural changes associated with CT for psychiatric disorders.

METHODS

We searched for cognitive training imaging studies in PubMed, Cochrane library, Scopus, and ProQuest electronic databases. We conducted an activation likelihood estimation (ALE) for coordinate-based meta-analysis of neuroimaging studies, conduct behavioral analysis of brain regions identified by ALE analysis, conduct behavioral analysis of brain regions identified by ALE analysis, and then created a functional meta-analytic connectivity model (fMACM) of the resulting regions.

RESULTS

Results showed that CT studies consistently reported increased activation in the left inferior frontal gyrus (IFG) and decreased activation in the left precuneus and cuneus from pre- to post- CT.

CONCLUSION

CT improves cognitive function by supporting language and memory function, and reducing neuronal resources associated with basic visual processing.

Cognitive Training Modulates Brain Hypersynchrony in a Population at Risk for Alzheimer's Disease

BACKGROUND

Recent studies demonstrated that brain hypersynchrony is an early sign of dysfunction in Alzheimer's disease (AD) that can represent a proxy for clinical progression. Conversely, non-pharmacological interventions, such as cognitive training (COGTR), are associated with cognitive gains that may be underpinned by a neuroprotective effect on brain synchrony.

OBJECTIVE

To study the potential of COGTR to modulate brain synchrony and to eventually revert the hypersynchrony phenomenon that characterizes preclinical AD.

METHODS

The effect of COGTR was examined in a sample of healthy controls (HC, n = 41, 22 trained) and individuals with subjective cognitive decline (SCD, n = 49, 24 trained). Magnetoencephalographic (MEG) activity and neuropsychological scores were acquired before and after a ten-week COGTR intervention aimed at improving cognitive function and daily living performance. Functional connectivity (FC) was analyzed using the phase-locking value. A mixed-effects ANOVA model with factors time (pre-intervention/post-intervention), training (trained/non-trained), and diagnosis (HC/SCD) was used to investigate significant changes in FC.

RESULTS

We found an average increase in alpha-band FC over time, but the effect was different in each group (trained and non-trained). In the trained group (HC and SCD), we report a reduction in the increase in FC within temporo-parietal and temporo-occipital connections. In the trained SCD group, this reduction was stronger and showed a tentative correlation with improved performance in different cognitive tests.

CONCLUSION

COGTR interventions could mitigate aberrant increases in FC in preclinical AD, promoting brain synchrony normalization in groups at a higher risk of developing dementia.

Multifocal Transcranial Direct Current Stimulation Modulates Resting-State Functional Connectivity in Older Adults Depending on the Induced Current Density

Combining non-invasive brain stimulation (NIBS) with resting-state functional magnetic resonance imaging (rs-fMRI) is a promising approach to characterize and potentially optimize the brain networks subtending cognition that changes as a function of age. However, whether multifocal NIBS approaches are able to modulate rs-fMRI brain dynamics in aged populations, and if these NIBS-induced changes are consistent with the simulated electric current distribution on the brain remains largely unknown. In the present investigation, thirty-one cognitively healthy older adults underwent two different multifocal real transcranial direct current stimulation (tDCS) conditions (C1 and C2) and a sham condition in a crossover design during a rs-fMRI acquisition. The real tDCS conditions were designed to electrically induce two distinct complex neural patterns, either targeting generalized frontoparietal cortical overactivity (C1) or a detachment between the frontal areas and the posteromedial cortex (C2). Data revealed that the two tDCS conditions modulated rs-fMRI differently. C1 increased the coactivation of multiple functional couplings as compared to sham, while a smaller number of connections increased in C1 as compared to C2. At the group level, C1-induced changes were topographically consistent with the calculated electric current density distribution. At the individual level, the extent of tDCS-induced rs-fMRI modulation in C1 was related with the magnitude of the simulated electric current density estimates. These results highlight that multifocal tDCS procedures can effectively change rs-fMRI neural functioning in advancing age, being the induced modulation consistent with the spatial distribution of the simulated electric current on the brain. Moreover, our data supports that individually tailoring NIBS-based interventions grounded on subject-specific structural data might be crucial to increase tDCS potential in future studies amongst older adults.

The Effectiveness of Computerized Cognitive Training Combined With Whole Body Cryotherapy in Improving Cognitive Functions in Older Adults. A Case Control Study

Objectives: Subjective Cognitive Decline (SCD) and Mild Cognitive Impairment (MCI) are common in elderly population, and constitute a high-risk group for progression to dementia. Innovative, complex, and engaging non-pharmacological methods of cognitive stimulation, implementable at this stage, are needed. The aim of the study was to determine the effect of Computerized Cognitive Training (CCT) combined with Whole Body Stimulation (WBC) on cognitive functions of older adults with SCD and MCI. Methods: A 9-week single-blind pre/post case control trial was conducted. The study enrolled 84 adults aged 60 or older, allocated to one of two intervention groups: EG; CCT with psychoeducation, EG2; CCT with psychoeducation and 10 WBC sessions, or the control group (CG), which comprised patients receiving usual care. The primary outcome measures were cognitive functions evaluated with MoCA scale and several other neuropsychological tools. Depressive symptoms assessed with the GDS scale constituted the secondary outcome measures. Results: The results show evidence for increased performance in the assessment of general cognitive functioning in both EGs (p ≤ 0.05). Significant improvement was also visible in several cognitive domains, such as verbal fluency (EG1 & EG2), learning ability and immediate memory (EG1 & EG2), delayed memory (EG2), attentional control (EG1), and information processing (EG2) (p ≤ 0.05). However, only in the group with combined interventions (CCT + WBC) the participants presented significantly less depressive symptoms (p ≤ 0.05). Conclusions: The results of the study suggest that CCT, especially in combination with WBC, might be a practical and effective method of improving cognitive performance. Moreover, this combination leads to a reduction of depressive symptoms.

The Cognition and Flow Study: A Feasibility Randomized Controlled Trial of the Effects of Cognitive Training on Cerebral Blood Flow

BACKGROUND

Cognitive training (CT) has demonstrated benefits for healthy older adults (HG) and mild cognitive impairment (MCI), but the effects on vascular function are unknown.

OBJECTIVE

This is a feasibility trial investigating the effects of CT on cerebral blood flow velocity (CBFv).

METHODS

Twenty HG, 24 with Alzheimer's disease (AD), and 12 with MCI were randomized to 12 weeks of multi-domain CT or control. Outcomes included: cognition (Addenbrooke's Cognitive Examination III), mood, quality of life (QoL), physical, and neurovascular function (transcranial Doppler ultrasonography measured task activation of CBFv responses). Data are presented as mean difference (MD) and 95% confidence interval (CI).

RESULTS

47 participants completed the trial. There were three dropouts from the training arm in the AD group, and one in the HG group. The intervention was acceptable and feasible to the majority of participants with a high completion rate (89%). The dropout rate was higher among participants with dementia. Few changes were identified on secondary analyses, but QoL was significantly improved in HG post-training (MD: 4.83 [95% CI: 1.13, 8.54]). CBFv response rate was not significantly different in HG (MD: 1.84 [95% CI: -4.81, 1.12]), but a significant increase was seen in the patient group (MD: 1.79 [95% CI: 0.005, 3.58]), requiring sample sizes of 56 and 84 participants respectively for a fully-powered trial.

CONCLUSION

A 12-week CT program was acceptable and feasible in HG, AD, and MCI. CT may be associated with alterations in vascular physiology which require further investigation in an appropriately powered randomized controlled trial.

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.

Object-Location Memory Training in Older Adults Leads to Greater Deactivation of the Dorsal Default Mode Network

Substantial evidence indicates that cognitive training can be efficacious for older adults, but findings regarding training-related brain plasticity have been mixed and vary depending on the imaging modality. Recent years have seen a growth in recognition of the importance of large-scale brain networks on cognition. In particular, task-induced deactivation within the default mode network (DMN) is thought to facilitate externally directed cognition, while aging-related decrements in this neural process are related to reduced cognitive performance. It is not yet clear whether task-induced deactivation within the DMN can be enhanced by cognitive training in the elderly. We previously reported durable cognitive improvements in a sample of healthy older adults (age range = 60-75) who completed 6 weeks of process-based object-location memory training (N = 36) compared to an active control training group (N = 31). The primary aim of the current study is to evaluate whether these cognitive gains are accompanied by training-related changes in task-related DMN deactivation. Given the evidence for heterogeneity of the DMN, we examine task-related activation/deactivation within two separate DMN branches, a ventral branch related to episodic memory and a dorsal branch more closely resembling the canonical DMN. Participants underwent functional magnetic resonance imaging (fMRI) while performing an untrained object-location memory task at four time points before, during, and after the training period. Task-induced (de)activation values were extracted for the ventral and dorsal DMN branches at each time point. Relative to visual fixation baseline: (i) the dorsal DMN was deactivated during the scanner task, while the ventral DMN was activated; (ii) the object-location memory training group exhibited an increase in dorsal DMN deactivation relative to the active control group over the course of training and follow-up; (iii) changes in dorsal DMN deactivation did not correlate with task improvement. These results indicate a training-related enhancement of task-induced deactivation of the dorsal DMN, although the specificity of this improvement to the cognitive task performed in the scanner is not clear.

Cognition in Healthy Aging

The study of cognitive change across a life span, both in pathological and healthy samples, has been heavily influenced by developments in cognitive psychology as a theoretical paradigm, neuropsychology and other bio-medical fields; this alongside the increase in new longitudinal and cohort designs, complemented in the last decades by the evaluation of experimental interventions. Here, a review of aging databases was conducted, looking for the most relevant studies carried out on cognitive functioning in healthy older adults. The aim was to review not only longitudinal, cross-sectional or cohort studies, but also by intervention program evaluations. The most important studies, searching for long-term patterns of stability and change of cognitive measures across a life span and in old age, have shown a great range of inter-individual variability in cognitive functioning changes attributed to age. Furthermore, intellectual functioning in healthy individuals seems to decline rather late in life, if ever, as shown in longitudinal studies where age-related decline of cognitive functioning occurs later in life than indicated by cross-sectional studies. The longitudinal evidence and experimental trials have shown the benefits of aerobic physical exercise and an intellectually engaged lifestyle, suggesting that bio-psycho-socioenvironmental factors concurrently with age predict or determine both positive or negative change or stability in cognition in later life.

Neural correlates of working memory training: Evidence for plasticity in older adults

Brain activity typically increases with increasing working memory (WM) load, regardless of age, before reaching an apparent ceiling. However, older adults exhibit greater brain activity and reach ceiling at lower loads than younger adults, possibly reflecting compensation at lower loads and dysfunction at higher loads. We hypothesized that WM training would bolster neural efficiency, such that the activation peak would shift towards higher memory loads after training. Pre-training, older adults showed greater recruitment of the WM network than younger adults across all loads, with decline at the highest load. Ten days of adaptive training on a verbal WM task improved performance and led to greater brain responsiveness at higher loads for both groups. For older adults the activation peak shifted rightward towards higher loads. Finally, training increased task-related functional connectivity in older adults, both within the WM network and between this task-positive network and the task-negative/default-mode network. These results provide new evidence for functional plasticity with training in older adults and identify a potential signature of improvement at the neural level.

The Effects of Cognitive Training on Brain Network Activity and Connectivity in Aging and Neurodegenerative Diseases: a Systematic Review

Cognitive training (CT) is an increasingly popular, non-pharmacological intervention for improving cognitive functioning in neurodegenerative diseases and healthy aging. Although meta-analyses support the efficacy of CT in improving cognitive functioning, the neural mechanisms underlying the effects of CT are still unclear. We performed a systematic review of literature in the PubMed, Embase and PsycINFO databases on controlled CT trials (N > 20) in aging and neurodegenerative diseases with pre- and post-training functional MRI outcomes up to November 23rd 2018 (PROSPERO registration number CRD42019103662). Twenty articles were eligible for our systematic review. We distinguished between multi-domain and single-domain CT. CT induced both increases and decreases in task-related functional activation, possibly indicative of an inverted U-shaped curve association between regional brain activity and task performance. Functional connectivity within ‘cognitive’ brain networks was consistently reported to increase after CT while a minority of studies additionally reported increased segregation of frontoparietal and default mode brain networks. Although we acknowledge the large heterogeneity in type of CT, imaging methodology, in-scanner task paradigm and analysis methods between studies, we propose a working model of the effects of CT on brain activity and connectivity in the context of current knowledge on compensatory mechanisms that are associated with aging and neurodegenerative diseases.

Associations Between Drinking and Cortical Thickness in Younger Adult Drinkers: Findings From the Human Connectome Project

BACKGROUND

Previous neuroimaging studies examining relations between alcohol misuse and cortical thickness have revealed that increased drinking quantity and alcohol-related problems are associated with thinner cortex. Although conflicting regional effects are often observed, associations are generally localized to frontal regions (e.g., dorsolateral prefrontal cortex [DLPFC], inferior frontal gyrus [IFG], and anterior cingulate cortex). Inconsistent findings may be attributed to methodological differences, modest sample sizes, and limited consideration of sex differences.

METHODS

This study examined neuroanatomical correlates of drinking quantity and heavy episodic drinking in a large sample of younger adults (N = 706; Mage  = 28.8; 51% female) using magnetic resonance imaging data from the Human Connectome Project. Exploratory analyses examined neuroanatomical correlates of executive function (flanker task) and working memory (list sorting).

RESULTS

Hierarchical linear regression models (controlling for age, sex, education, income, smoking, drug use, twin status, and intracranial volume) revealed significant inverse associations between drinks in past week and frequency of heavy drinking and cortical thickness in a majority of regions examined. The largest effect sizes were found for frontal regions (DLPFC, IFG, and the precentral gyrus). Follow-up regression models revealed that the left DLPFC was uniquely associated with both drinking variables. Sex differences were also observed, with significant effects largely specific to men.

CONCLUSIONS

This study adds to the understanding of brain correlates of alcohol use in a large, gender-balanced sample of younger adults. Although the cross-sectional methodology precludes causal inferences, these findings provide a foundation for rigorous hypothesis testing in future longitudinal investigations.