The effects of aerobic exercise and transcranial direct current stimulation on cognitive function in older adults with and without cognitive impairment: A systematic review and meta-analysis

Comparative efficacy of exercise interventions for cognitive health in older adults: A network meta-analysis

BACKGROUND

Previous studies have consistently demonstrated that exercise mitigates cognitive decline in older adults. However, the most effective types of exercise, along with optimal frequency and duration of interventions, remain inadequately defined. To address these gaps, we conducted a network meta-analysis synthesizing direct and indirect evidence from existing literature to identify the most effective exercise interventions for enhancing cognitive function in older adults.

METHODS

We conducted a systematic search across databases including PubMed and Web of Science to identify randomized controlled trials (RCTs) evaluating the impact of various exercise interventions on cognitive function in older adults. We assessed the quality of included studies and performed a traditional meta-analysis with Review Manager 5.3. Subsequently, a network meta-analysis was conducted using Stata 17.0 to evaluate the effects of different exercise modalities on cognitive outcomes, specifically memory, inhibitory control, and task-switching abilities.

RESULTS

A total of 37 studies encompassing 2585 older adults met the inclusion criteria. The network meta-analysis revealed that resistance training exerted the strongest effect on overall cognitive improvement. Aerobic exercise, multimodal exercise, and physical-mental training followed in effectiveness. Specifically, resistance training significantly enhanced inhibitory control compared to high-intensity interval training (HIIT), aerobic exercise, and other modalities. Physical-mental training emerged as the most effective intervention for improving task-switching ability and demonstrated superior efficacy in enhancing working memory compared to aerobic exercise. Conversely, aerobic exercise showed the strongest effect on memory function, outperforming resistance training, multimodal exercise, and physical-mental training.

CONCLUSION

Resistance training is the most effective exercise modality for enhancing overall cognitive function and inhibitory control in older adults. Physical-mental training offers the greatest benefits for improving working memory and task-switching ability, while aerobic exercise is most beneficial for enhancing memory function. Based on these findings, the recommended exercise protocols are: Resistance Training: 12 weeks, 2-3 times per week, 45 min per session. Aerobic Exercise: 21 weeks, twice per week, 60 min per session. These tailored exercise interventions can inform public health strategies and clinical practices aimed at optimizing cognitive health in the aging population.

REGISTRATION

The protocol for this review was registered in PROSPERO (CRD42024597545).

Transcranial direct current stimulation associated with physical exercise can help smokers to quit smoking: a randomized controlled trial

Chronic exposure to nicotine is related to low activity in the prefrontal cortex and insular hyperactivity in smokers. Therefore, addiction has been the target of experimental studies in aerobic exercise (AE) and transcranial direct current stimulation (tDCS). Thus, the objective of this study was to verify the effect of AE and anodal tDCS at F4 and cathodal at T3 on craving, motivation to change smoking behaviour (MCSB) and brain reactivity (BR) in smokers. The sample consisted of 41 chronic smokers distributed into four groups: tDCS (G1), AE (G2), tDCS combined with AE (G3) and sham tDCS combined with AE (G4). All volunteers underwent 5 consecutive sessions of the intended intervention. Before starting the intervention protocol and after the last intervention session, the volunteers answered questionnaires and underwent an electroencephalogram exam, to evaluate the variables investigated. The results demonstrated that AE, when associated with active tDCS, was effective in promoting a reduction in craving (p < 0,05), cigarette consumption (p < 0,05), and BR (p < 0,05) during exposure to smoking cues, in addition to increasing MCSB (p < 0,05). Therefore, only when associated with AE, tDCS was able to modulate positive effects on smoking.

A systematic review and meta-analysis of the impact of transcranial direct current stimulation on cognitive function in older adults with cognitive impairments: the influence of dosage parameters

INTRODUCTION

Numerous studies have demonstrated the effects of transcranial direct current stimulation (tDCS) on cognitive function in the older people. This study further explores the impact of tDCS and its dosage parameters on cognitive enhancement in older people with cognitive impairments.

METHODS

Randomized controlled trials (RCTs) published through November 2023 were retrieved from databases including PubMed, Scopus, EMBASE, EBSCO, and the Cochrane Library. Participants were older adults with cognitive impairments, including Alzheimer's disease (AD), mild cognitive impairment (MCI), and dementia. AD was diagnosed based on the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition (DSM-IV), or the National Institute of Neurological and Communicative Disorders and Stroke - Alzheimer' Disease and Related Disorders Association (NINCDS-ADRDA) criteria. Dementia was diagnosed using the DSM-V or NINCDS-ADRDA criteria, while MCI was diagnosed using the DSM-V, the Petersen criteria, or assessments such as Montreal Cognitive Assessment (MoCA) and Clinical Dementia Rating (CDR). Standardized mean difference (SMD) values were analyzed to assess the effects.

RESULTS

A total of 19 RCTs were included. tDCS significantly improved the Mini-Mental State Examination score both immediately post-intervention (SMD = 0.51, p = 0.005) and at follow-up (SMD = 2.29, p = 0.0003). Significant effects were observed when tDCS was used alone (SMD = 0.39, p = 0.04), at current densities ≤ 0.06 mA/cm2 (SMD = 0.25, p = 0.04), session durations exceeding 20 min (SMD = 0.89, p = 0.01), up to 15 sessions (SMD = 0.28, p = 0.009), and when an active electrode was placed over the temporal area (SMD = 0.33, p = 0.02). People with AD showed greater improvements compared to those with MCI or dementia (SMD = 0.91, p = 0.02). However, tDCS did not significantly improve memory or executive function.

CONCLUSION

tDCS demonstrated efficacy in enhancing global cognition in older people with cognitive impairments, providing insight into optimal parameters for clinical application. However, no improvement were observed in memory or executive function.

Repetitive Transcranial Magnetic Stimulation and Tai Chi Chuan for Older Adults With Sleep Disorders and Mild Cognitive Impairment: A Randomized Clinical Trial

Importance

Sleep disorders and mild cognitive impairment (MCI) commonly coexist in older adults, increasing their risk of developing dementia. Long-term tai chi chuan has been proven to improve sleep quality in older adults. However, their adherence to extended training regimens can be challenging. Repetitive transcranial magnetic stimulation (rTMS) is a neuromodulation technique that may enhance the benefits of exercise.

Objective

To investigate whether 1-Hz rTMS of the right dorsolateral prefrontal cortex could enhance the clinical benefits of tai chi chuan in improving sleep quality and cognitive function among older adults with sleep disorders and MCI.

Design, Setting, and Participants

This 2-arm, sham-controlled, assessor-masked randomized clinical trial was conducted at a university hospital in China between October 2022 and February 2024. Adults aged 60 to 75 years with sleep disorders and MCI were eligible. Data analysis was performed from February to May 2024.

Intervention

Participants were randomized in a 1:1 ratio to an experimental group (tai chi chuan and 1-Hz rTMS) or a sham group (tai chi chuan and sham rTMS). Each participant received 30 sessions of personalized rTMS targeting the right dorsolateral prefrontal cortex, and the sham group underwent the same procedure. The 2 groups received 30 sessions of 60 minutes of the 24-form simplified tai chi chuan, 5 times per week for 6 weeks.

Main Outcomes and Measures

The primary outcomes were subjective sleep quality assessed by the Pittsburgh Sleep Quality Index (PSQI), in which scores range from 0 to 21, with lower scores indicating a healthier sleep quality, and global cognitive function assessed by the Montreal Cognitive Assessment (MoCA), in which scores range from 0 to 30, with higher scores indicating less cognitive impairment. The secondary outcomes included measures of objective sleep actigraphy, anxiety and depression scales, and other cognitive subdomains. Assessments were performed at baseline, 6 weeks after the intervention, and at the 12-week follow-up.

Results

A total of 110 participants (mean [SD] age, 67.9 [4.6] years; 68 female [61.8%]) were randomized to the experimental group (n = 55) and the sham group (n = 55) and included in the intention-to-treat analysis. At 6 weeks after the intervention, compared with the sham group, the experimental group showed a lower PSQI score (between-group mean difference, -3.1 [95% CI, -4.2 to -2.1]; P < .001) and a higher MoCA score (between-group mean difference, 1.4 [95% CI, 0.7-2.1]; P < .001). The per-protocol dataset analyses and 12-week follow-up showed similar results. The generalized estimated equation model revealed an interaction effect between the PSQI score (mean difference, -2.1 [95% CI, -3.1 to -0.1]; P < .001) and the MoCA total score (mean difference, 0.9 [95% CI, 0.1-1.6]; P = .01). There were 7 nonserious, unrelated adverse events (experimental group: 2; sham group: 5) with no significant difference between the 2 groups.

Conclusions and Relevance

In this randomized clinical trial, the findings suggest that 1-Hz rTMS enhanced the clinical benefits of tai chi chuan in improving sleep quality and cognitive function among older adults with sleep disorders and MCI, which may be related to alterations in neural plasticity. These findings provide novel data on nonpharmacologic strategies for the rehabilitation of sleep disorders and may delay or even prevent MCI.

Trial Registration

Chinese Clinical Trial Registry Identifier: ChiCTR2200063274.

Transcranial Direct Current Stimulation for Cognitive Impairment Rehabilitation: A Bibliometric Analysis

BACKGROUND AND AIMS

As global demographics shift toward an older population, cognitive impairment is becoming increasingly critical. Transcranial Direct Current Stimulation (tDCS), an innovative brain stimulation technique, has the potential to significantly improve cognitive function. Our main aim is to comprehensively analyze the existing literature, identify key aspects of tDCS research in the rehabilitation of cognitive impairment, and predict future trends in this field.

METHODS

We used the Web of Science (WOS) database to search for English articles and reviews relevant to this topic. For visual analysis of the literature, we employed the WOS analysis tool, CiteSpace, along with VOSviewer software to ensure comprehensive analysis.

RESULTS

We included 2940 articles published between 1998 and 2023. Over 25 years, annual publications and citations in this field increased steadily, peaking at 379 articles in 2021. Michael A. Nitsche was a major contributor. Most articles came from developed countries, primarily North America and Europe, and journals generally had modest impact factors. Research in this field primarily aims to treat cognitive impairment resulting from pathological aging or neuropsychiatric disorders, with a particular focus on specific brain regions. Recently, researchers have integrated various treatment modalities with tDCS techniques to actively investigate effective strategies to mitigate cognitive impairments associated with pathological aging.

CONCLUSION

This study presents the first bibliometric analysis of the literature on tDCS in the rehabilitation of cognitive impairment, highlighting key areas of research and emerging trends. These findings provide critical insights for future tDCS interventions targeting cognitive impairment associated with pathological aging.

The mechanisms, hallmarks, and therapies for brain aging and age-related dementia

Age-related cognitive decline and dementia are significant manifestations of brain aging. As the elderly population grows rapidly, the health and socio-economic impacts of cognitive dysfunction have become increasingly significant. Although clinical treatment of dementia has faced considerable challenges over the past few decades, with limited breakthroughs in slowing its progression, there has been substantial progress in understanding the molecular mechanisms and hallmarks of age-related dementia (ARD). This progress brings new hope for the intervention and treatment of this disease. In this review, we categorize the latest findings in ARD biomarkers into four stages based on disease progression: Healthy brain, pre-clinical, mild cognitive impairment, and dementia. We then systematically summarize the most promising therapeutic approaches to prevent or slow ARD at four levels: Genome and epigenome, organelle, cell, and organ and organism. We emphasize the importance of early prevention and detection, along with the implementation of combined treatments as multimodal intervention strategies, to address brain aging and ARD in the future.

Effects of aerobic exercise on executive function of healthy middle-aged and older adults: A systematic review and meta-analysis

BACKGROUND

The deterioration of executive function is a hallmark of cognitive aging. Reports indicate that signs of decline in executive function begin to emerge as early as middle age. Aerobic exercise improves executive function in healthy middle-aged and older adults, but the optimal exercise prescription variables are still unclear.

OBJECTIVE

To investigate the effects of aerobic exercise on executive function of healthy middle-aged and older adults and explore the dose-response relationship and moderators.

METHODS

We conducted comprehensive searches of PubMed, Embase, Cochrane Central Register of Controlled Trials, Web of Science, Scopus, PsycINFO, and SPORTDiscus for English literature, and CNKI, WanFang, and VIP for Chinese literature, covering the period from inception until April 25, 2024. Randomized controlled trials examining the effect of aerobic exercise on executive function in healthy middle-aged and older adults aged 45 or older were included. The Cochrane Collaboration's RoB2 tool was used to assess the methodological quality of the included studies. And subgroup analyses and meta-regressions were conducted to elucidate the impact of aerobic exercise on executive function.

RESULTS

Forty-two eligible randomized controlled trials, involving a total of 2881 participants, met the inclusion criteria for the systematic review and meta-analysis. The pooled results showed that aerobic exercise had positive effects on improving cognitive flexibility (Hedge's g = 0.343, p < 0.001), working memory (Hedge's g = 0.392, p < 0.001), and inhibitory control (Hedge's g = 0.229, p < 0.001) in healthy middle-aged and older adults. However, it did not demonstrate an improvement in planning (Hedge's g = 0.094, p = 0.440). The dose-response relationships between different exercise parameters and subdomains of executive functions revealed that the largest effects on cognitive flexibility were observed after 13-24 weeks of progression-intensity mind-body exercise, 46-60 min per session, and 5-7 days per week. Regarding working memory, the largest effects were observed after 13-24 weeks of progression-intensity general aerobic exercise, 20-45 min per session, and 5-7 days per week. For inhibitory control, the greatest effects were noted after 13-24 weeks of low-intensity general aerobic exercise, 20-45 min per session, and 3-4 days per week.

CONCLUSION

Aerobic exercise can significantly improve cognitive flexibility, working memory, and inhibitory control in healthy middle-aged and older adults. The effect of aerobic exercise on different aspects of executive function is influenced by specific exercise parameters, suggesting that personalized aerobic exercise programs may be more effective for enhancing executive function of healthy middle-aged and older adults.

Lifestyle, Environment, and Dietary Measures Impacting Cognitive Impairment: The Evidence Base for Cognitive Subtypes

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Cognition includes all phases of valid functions and processes, e.g., sensitivity, judgment, assessment, and decision-making. Thinking is also a cognitive procedure since it involves considering potential opportunities. There are various types of cognition. Hot cognition involves mental procedures where emotion plays a role, while cold cognition includes mental processes that do not include feelings or emotions. Cognitive memories of various types include sensor memory, sensing touch, smell, and sight; short-term memory allows one to recall, e.g., what one had for lunch a few days ago; working memory includes remembering telephone numbers or directions to a destination; and long-term memory comprises of major milestones in life and recalling one’s childhood events. These are further classified as episodic, e.g., the first day in primary school, and semantic memories, such as recalling the capital city of a country and filling out crossword puzzles. Declarative memories include remembering significant past events, such as global information. Cognition is affected by factors, such as nutrition, aging, addiction, environment, mental health, physical activity, smoking, and keeping the brain active. Consumption of plant- based foods plays a prominent role in the prevention of cognitive memory. Playing games and instruments, reading books, and being socially active make life more satisfying, thus assisting in the preservation of mental function and slowing mental decline.

Harnessing Brainwave Entrainment: A Non-invasive Strategy To Alleviate Neurological Disorder Symptoms

From 1990-2019, the burden of neurological disorders varied considerably across countries and regions. Psychiatric disorders, often emerging in early to mid-adulthood, are linked to late-life neurodegenerative diseases like Alzheimer's disease and Parkinson's disease. Individuals with conditions such as Major Depressive Disorder, Anxiety Disorder, Schizophrenia, and Bipolar Disorder face up to four times higher risk of developing neurodegenerative disorders. Contrarily, 65 % of those with neurodegenerative conditions experience severe psychiatric symptoms during their illness. Further, the limitation of medical resources continues to make this burden a significant global and local challenge. Therefore, brainwave entrainment provides therapeutic avenues for improving the symptoms of diseases. Brainwaves are rhythmic oscillations produced either spontaneously or in response to stimuli. Key brainwave patterns include gamma, beta, alpha, theta, and delta waves, yet the underlying physiological mechanisms and the brain's ability to shift between these dynamic states remain areas for further exploration. In neurological disorders, brainwaves are often disrupted, a phenomenon termed "oscillopathy". However, distinguishing these impaired oscillations from the natural variability in brainwave activity across different regions and functional states poses significant challenges. Brainwave-mediated therapeutics represents a promising research field aimed at correcting dysfunctional oscillations. Herein, we discuss a range of non-invasive techniques such as non-invasive brain stimulation (NIBS), neurologic music therapy (NMT), gamma stimulation, and somatosensory interventions using light, sound, and visual stimuli. These approaches, with their minimal side effects and cost-effectiveness, offer potential therapeutic benefits. When integrated, they may not only help in delaying disease progression but also contribute to the development of innovative medical devices for neurological care.

The effects of repetitive transcranial magnetic and transcranial direct current stimulation on memory functions in older adults with mild cognitive impairment: a systematic review and meta-analysis

Mild cognitive impairment (MCI) is a condition that impairs activities of daily living, and often transforms to dementia. Repetitive transcranial magnetic stimulation (rTMS) and transcranial direct current stimulation (tDCS) show promise in improving cognitive functions in MCI patients. In this meta-analysis, we aimed to compare the effects of rTMS and tDCS on memory functions in MCI patients. We explored eight databases from their inception to March 16, 2024. We obtained 11 studies with 406 patients with MCI. We used the standardized mean difference (SMD) with a 95% confidence interval (CI) to synthesize the effect size. rTMS and tDCS significantly improved memory functions in MCI patients (SMD = 0.61; 95% CI: 0.41-0.82; p < 0.00001; I2 = 22%). In subgroup analysis of number of stimulation sessions, both rTMS and tDCS over 10 sessions (SMD = 0.84; 95% CI: 0.50-1.17, p < 0.00001, I2 = 0%) significantly improved the memory function in MCI patients. The subgroup analyses on different stimulation types (SMD = 0.78; 95% CI: 0.51-1.06; p < 0.00001; I2 = 0%) and treatment persistent effects (SMD = 0.93; 95% CI: 0.51-1.35, p < 0.0001, I2 = 0%) showed that rTMS was more effective than tDCS. rTMS with a stimulation frequency of 10 Hz (SMD = 0.86; 95% CI: 0.51-1.21; p < 0.00001; I2 = 0%) and over 10 sessions (SMD = 0.98; 95% CI: 0.58-1.38; p < 0.00001; I2 = 0%) at multiple sites (SMD = 0.97; 95% CI: 0.44-1.49; p = 0.0003; I2 = 0%) showed a great improvement in the memory performance of patients with MCI. rTMS was more likely to appear temporary side effects (risk ratio (RR) = 3.18, 95% CI: 1.29-7.83, p = 0.01). This meta-analysis suggests that rTMS and tDCS are safe and efficient tools to improve memory functions in patients with MCI, while rTMS had a larger effect than tDCS. rTMS with a stimulation frequency of 10 Hz targeted on multiple sites over 10 sessions showed the greatest effect. We could not conclude parameters of tDCS because of insufficient data.

Systematic Review Registration

https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42024558991.

Does Transcranial Direct Current Stimulation Affect Potential P300-Related Events in Vascular Dementia? Considerations from a Pilot Study

Vascular dementia, the second most common type of dementia, currently lacks a definitive cure. In the pursuit of therapies aimed at slowing its progression and alleviating symptoms, transcranial direct current stimulation (tDCS) emerges as a promising approach, characterized by its non-invasive nature and the ability to promote brain plasticity. In this study, the primary objective was to investigate the effects of a two-week cycle of tDCS on the dorsolateral prefrontal cortex (DLPFC) and neurophysiological functioning in thirty patients diagnosed with vascular dementia. Each participant was assigned to one of two groups: the experimental group, which received anodal tDCS to stimulate DPCFL, and the control group, which received sham tDCS. Neurophysiological functions were assessed before and after tDCS using P300 event-related potentials (ERPs), while neuropsychological function was evaluated through a Mini-Mental State Examination (MMSE). The results showed a reduction in P300 latency, indicating a faster cognitive process; an increase in P300 amplitude, suggesting a stronger neural response to cognitive stimuli; and a significant improvement in MMSE scores compared to the control group, indicating an overall enhancement in cognitive functions. These findings suggest that tDCS could represent a promising therapeutic option for improving both neurophysiological and cognitive aspects in patients with vascular dementia.

Resistance training's impact on blood biomarkers and cognitive function in older adults with low and high risk of mild cognitive impairment: a randomized controlled trial

BACKGROUND

The aging brain exhibits a neuroinflammatory state, driven partly by peripheral pro-inflammatory stimuli, that accelerates cognitive deterioration. A growing body of evidence clearly indicates that physical exercise partly alleviates neuroinflammation and positively affects the aging process and cognition. In this randomized controlled trial, we aimed to observe the effect of 12 weeks of resistance training (RT) on peripheral biomarker levels, cognitive function changes and their interrelationship, and explore differences in those exercise-induced changes in older adults with high risk of mild cognitive impairment (MCI) compared to older adults with low risk of MCI.

METHODS

Fifty-two participants (aged 60-85 years old, 28 female) were randomly allocated to a 12 week lower limb RT program consisting of two training sessions per week or waiting list control group. The Montreal Cognitive Assessment (MoCA) was used to stratify participants screened as high (< 26/30) or low risk (≥ 26/30) of MCI. We assessed serum Interleukin 6 (IL-6), Insulin-like Growth Factor-1 (IGF-1), and Kynurenine (KYN) levels. Cognitive measurement consisted of and four subtests of Automated Neuropsychological Assessment Metrics (ANAM), the two-choice reaction time, go/no-go, mathematical processing, and memory search test.

RESULTS

Twelve weeks of RT improved Go/No-go test results in older adults with high MCI risk. RT did not significantly affect blood biomarkers. However, IGF-1 level increases were associated with improvements in response time on the mathematical processing test in the exercise group, and IL-6 level increases were associated with improvements in response time on the memory search test in the total group of participants. Finally, KYN levels significantly differed between older adults with low and high MCI risk but no significant associations with performance were found.

CONCLUSION

Our study results suggest a different effect of RT on inhibitory control between older adults with low compared to high MCI risk. IGF-1 may play a role in the mechanism behind the cognitive benefit of RT and KYN may be a surrogate biomarker for neurodegeneration and cognitive decline.

Noninvasive brain stimulations modulated brain modular interactions to ameliorate working memory in community-dwelling older adults

Non-invasive brain stimulations have drawn attention in remediating memory decline in older adults. However, it remains unclear regarding the cognitive and neural mechanisms underpinning the neurostimulation effects on memory rehabilitation. We evaluated the intervention effects of 2-weeks of neurostimulations (high-definition transcranial direct current stimulation, HD-tDCS, and electroacupuncture, EA versus controls, CN) on brain activities and functional connectivity during a working memory task in normally cognitive older adults (age 60+, n = 60). Results showed that HD-tDCS and EA significantly improved the cognitive performance, potentiated the brain activities of overlapping neural substrates (i.e. hippocampus, dlPFC, and lingual gyrus) associated with explicit and implicit memory, and modulated the nodal topological properties and brain modular interactions manifesting as increased intramodular connection of the limbic-system dominated network, decreased intramodular connection of default-mode-like network, as well as stronger intermodular connection between frontal-dominated network and limbic-system-dominated network. Predictive model further identified the neuro-behavioral association between modular connections and working memory. This preliminary study provides evidence that noninvasive neurostimulations can improve older adults' working memory through potentiating the brain activity of working memory-related areas and mediating the modular interactions of related brain networks. These findings have important implication for remediating older adults' working memory and cognitive declines.

Modulatory effects of aerobic training on the degree centrality of brain functional activity in subthreshold depression

BACKGROUND

Aerobic training has been shown to effectively prevent the progression of depressive symptoms from subthreshold depression (StD) to major depressive disorder (MDD), and understanding how aerobic training promotes changes in neuroplasticity is essential to comprehending its antidepressant effects. Few studies, however, have quantified the alterations in spontaneous brain activity before and after aerobic training for StD.

METHODS

Participants included 44 individuals with StD and 34 healthy controls (HCs). Both groups underwent moderate aerobic training for eight weeks, and resting state functional magnetic resonance imaging (rs-fMRI) data were collected before and after training. The degree centrality (DC) changes between the two groups and the DC changes in each group before and after training were quantified.

RESULTS

The rs-fMRI results showed that compared with the HCs, the DC values of the StD group in the orbital region of the left inferior frontal gyrus significantly depreciated at baseline. After aerobic training, the results of the follow-up examination revealed no significant difference in the DC values between the two groups. In addition, compared with baseline, the StD group exhibited an significant decrease in the DC values of the left dorsolateral superior frontal gyrus; while the HCs group exhibited an significant decrease in the DC values of the left thalamus. No statistically significant connection was seen between changes in DC values and psychological scale scores in the StD group.

CONCLUSIONS

Our findings suggest that regular aerobic training can enhance brain plasticity in StD. In addition, we demonstrated that DC is a relevant and accessible method for evaluating the functional plasticity of the brain induced by aerobic training in StD.

Combined effects of transcranial direct current stimulation and aerobic exercise on inhibitory control function in healthy young adults: An event-related potential study

Transcranial direct current stimulation (tDCS) and aerobic exercise (AE) have been demonstrated to enhance inhibitory control function in healthy individuals separately. However, the potential benefits of combining these two interventions have yet to be fully explored. In this study, we aimed to use multiple event-related potential (ERP) components (P200, N200, and N450) to investigate the combined effects of tDCS and AE on the improvement of inhibitory control ability in healthy young adults. We evaluated the influence of this combined intervention on cognitive tasks involving inhibitory control function and basic information processing by performing the Stroop Word Color task. Our results showed that compared to the application of tDCS or AE alone, the combined intervention of tDCS and AE had a greater effect on improving inhibitory control function in healthy young adults. The amplitude of P200, N200, and N450 ERP components also changed more significantly during the Stroop Word Color task. We concluded that the mechanism of tDCS combined with AE in improving inhibitory control ability may involve synergistic effects on brain structures at different levels, such as regulating interactions at the reticular activating system level and activating corresponding brain regions at the medial frontal lobe and frontal lobe levels.

The effects of transcranial direct current stimulation on cognitive function for mild cognitive impairment: a systematic review and meta-analysis of randomized controlled trials

BACKGROUND

Transcranial direct current stimulation (tDCS) emerged as a potential modality for enhancing cognitive functions in patients with cognitive decline, including mild cognitive impairment (MCI). Our systematic review and meta-analysis aim to synthesize the available randomized controlled trials (RCTs) on the effects of tDCS on cognitive functions in patients with MCI.

METHODS

Our review protocol was registered on PROSPERO with ID: CRD42022360587. We conducted a systematic database search until September 2022. Standardized mean difference (SMD) and pooled effect size (ES) for robust variance estimation (RVE) method were used as effect estimates for our meta-analysis.

RESULTS

We included 11 RCTs with a total of 429 participants. The meta-analysis showed that, compared to sham groups, tDCS did not improve global functioning (measured by MOCA) (SMD = 0.02, CI =  - 0.30 to 0.35; p = 0.88), memory domain (ES = 0.681, CI =  - 2.15 to 3.51, p = 0.576), sustained attention (measured by TMT-A) (SMD =  - 0.21, CI =  - 0.52 to 0.10, p = 0.19), and executive function (measured by TMT-B) (SMD =  - 0.53, CI =  - 1.56 to 0.50, p = 0.20).

CONCLUSION

Our meta-analysis found no significant effect of tDCS on cognitive functions in MCI patients, including effects on global functioning, memory, sustained attention, and executive function. Therefore, an important change to be tested in future studies is to look for a better combination with tDCS for patients with MCI.

The relationships between plasma advanced glycation end products level and cognitive function in middle-aged and elderly Chinese subjects

OBJECTIVES

To determine the relationships between circulating representative advanced glycation end products (AGEs) and cognitive performance in middle-aged and elderly Chinese adults.

METHOD

A cross-sectional study with 1834 participants were included. Cognitive performance was assessed using the Mini-Mental State Examination (MMSE). Plasma free AGEs including Nε-carboxymethyl-L-lysine (CML), Nε-(1-carboxyethyl) lysine (CEL), S-carboxymethyl-L-cysteine (CMC) and Nδ-(5-hydro-5-methyl-4-imidazolon-2-yl)-ornithine (MG-H1) were measured by ultra-high performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). Multivariate adjusted linear and logistic regression analysis were used to explore the associations between plasma AGEs and cognitive function.

RESULTS

The prevalence of mild cognitive impairment (MCI) was 17.94%. Plasma CMC and MG-H1 level were negatively associated with MMSE score (β = -0.42, p < 0.001 for all) in the multivariate linear regression analysis. In the multivariate logistic regression analysis, compared to the lowest tertile, participants within the highest tertile of CMC and MG-H1 had increased risk of MCI [ORs (95% CI): 1.62 (1.21-2.17), P trend <0.001, and ORs (95% CI): 1.30 (0.97-1.76), P trend = 0.069, respectively]. In addition, the weighted quantile sum (WQS) index was negatively associated with MMSE (β = -0.48, P < 0.001) and increased risk of MCI [ORs (95% CI): 1.35 (1.20-1.52), P < 0.001].

CONCLUSION

Combined exposure of plasma free AGEs including CML, CEL, CMC and MG-H1 were associated with increased risk of cognitive impairment. Plasma CMC and MG-H1 might the main contributors for cognitive impairment, while further longitudinal studies are required to verify the associations.

The interaction between instrumental activities of daily living and dual sensory function on cognition among the elderly in China: A cross-sectional survey

To explore the interaction of instrumental activities of daily living (IADLs) and dual sensory function on cognition in the elderly. A cross-sectional survey was conducted in six general hospitals in China, from October 2022 to December 2022. Data collection included general information, IADLs scale, self-reported sensory function questionnaire, and mini-mental state examination (MMSE). Binary logistic regression was used to examine the association between factors and cognition. The interactive effect was evaluated by synergy index (S), relative excess risk due to interaction (RERI), and attributable proportion due to interaction (AP). The odds ratio (OR) of IADLs decline in cognition is 4.412 (95% confidence interval [CI]: 3.633-5.358, p < 0.001); the OR of dual sensory difficulty on cognition is 2.502 (95% CI: 1.272-4.921, p = 0.008). The OR of interaction between IADLs decline and dual sensory difficulty on cognition is 13.737 (95% CI: 9.726-19.400, p < 0.001). RERI (95% CI) = 7.823 (3.230-12.417), AP (95% CI) = 0.570 (0.392-0.747), S (95% CI) = 2.593 (1.616-4.160). IADLs decline and dual sensory difficulty are associated with cognitive decline. IADLs decline and dual sensory difficulty have interaction with cognitive decline; the interaction is greater than the sum effect of those two on cognitive decline independently. Sensory and IADLs assessment can be used as early screening items for cognition among the elderly. In addition, protecting sensory function and maintaining IADLs in the elderly can help protect their cognition.

Effects of physical activity interventions on executive function in older adults with dementia: A meta-analysis of randomized controlled trials

BACKGROUND

To date quantitative meta-analysis with large samples to investigate the effects and potential moderators of physical activity (PA) on executive function (EF) in older adults with dementia is insufficient. Therefore, we conducted this meta-analysis.

DESIGN

Meta-analysis of randomized controlled trials (RCTs).

PARTICIPANTS

Old people with Alzheimer's disease (AD) or related dementia of varying types and severity as the primary diagnosis.

METHODS

PubMed, Web of Science, the Cochrane Library and Embase databases were searched for relevant studies published from 01 January, 2010 to 01 March, 2022. The results of executive function were reported in all RCTs. Random-effects meta-analysis was used to calculate the size of effects. Subgroup analyses of three moderators (including the specific sub-domains of EF, exercise prescription variables, and sample characteristics) were performed.

RESULTS

Eighteen RCTs were included with a combined sample size of 1366. Overall, PA interventions improved overall EF (standardized mean difference [SMD]=0.23, 95% confidence interval [CI] 0.05 to 0.41, p<0.05). The EF sub-domain "planning" was significant moderator (SMD=0.31, 95%CI 0.11 to 1.51, p<0.01), but inhibitory control, working memory and cognitive flexibility were not significant. Regarding exercise prescription variables, type of resistance training; moderate intensity; total duration ≤24 weeks and short (once or twice a week) frequency improved overall EF performance. Session length may be a moderator. Regarding sample characteristics, old-old, AD and both dementia and AD had significant benefits.

CONCLUSIONS AND IMPLICATIONS

EF in older adults with AD or related dementia benefited from physical activity, and the benefit was affected by the type, intensity, total duration, frequency of exercise. Physical activity can be an alternative intervention in aging patients with dementia, to improve EF performance or prevent or EF decline.

Gender differences in the modifying effect of living arrangements on the association of sleep quality with cognitive function among community-dwelling older adults: a cross-sectional study

Background

Sleep quality is considered to be associated with cognitive function for older adults, but little is known about whether living with others can buffer mild cognitive impairment in older adults with poor sleep quality. The objective of this study was to examine the role of living arrangements in sleep quality and cognitive function among older adults aged 65 and over.

Methods

2,859 older adults over 65 years old were selected by using multi-stage stratified sampling method. Cognitive function and sleep quality were measured using Mini-Mental State Examination (MMSE) and Pittsburgh Sleep Quality Index (PSQI). Binary logistic regression was performed to examine the relationship between sleep quality and mild cognitive impairment, and the interaction effects of sleep quality and living arrangements on mild cognitive impairment stratified by gender.

Results

Poor sleep quality was associated with mild cognitive impairment among men and women regardless of living arrangements. The significantly protective role of living with others in reducing the incidence of mild cognitive impairment was found in men with poor sleep quality, but not in women.

Conclusion

Targeted support for older adults with poor sleep quality may be effective in preventing mild cognitive impairment, and gender differences should be taken into account when promoting cohabitations.