Physical exercise as a preventive or disease-modifying treatment of dementia and brain aging

Towards new perspectives: A scoping review and meta-synthesis to redefine brain health for multiple sclerosis

BACKGROUND AND PURPOSE

Research promoting the health of the brain has increased exponentially over the last decade. The importance of 'brain health' for multiple sclerosis (MS), as one example, is a high priority. However, as research into the concept increases, so does varied use of the term.

METHODS

A scoping review, guided by the methodological framework of the Joanna Briggs Institute, was conducted to collate the evidence relating to brain health for MS. A comprehensive literature search incorporated six search strategies to retrieve both scientific and grey literature sources. All evidence sources were qualitatively charted and synthesized (meta-synthesis) according to their definition of brain health used, outcome measures and brain-healthy lifestyle elements.

RESULTS

Seventy evidence sources (34 peer reviewed, 36 grey literature) were eligible for inclusion. Of these, just over half (n = 40, 57%) provided a definition of brain health. The most common definition alluded to the biomedical model of neurological reserve (n = 22, 55%), a self-remodelling theory described to retain optimal brain function. Twenty-nine outcome measures of brain health were identified, the most frequent being magnetic resonance imaging metrics (n = 25, 83%). Physical activity was the most prevalent brain-healthy lifestyle element (n = 44), followed by avoidance of smoking (n = 26) and diet (n = 24).

CONCLUSIONS

Brain health should be considered a primary target for optimal disease and lifestyle management across the MS disease course. A working definition reflecting a shift from a medical lens towards broader biopsychosocial contexts that may influence brain health for people living with MS is proposed.

Randomized controlled trials of non-pharmacological interventions for healthy seniors: Effects on cognitive decline, brain plasticity and activities of daily living-A 23-year scoping review

Little is known about the simultaneous effects of non-pharmacological interventions (NPI) on healthy older adults' behavior and brain plasticity, as measured by psychometric instruments and magnetic resonance imaging (MRI). The purpose of this scoping review was to compile an extensive list of randomized controlled trials published from January 1, 2000, to August 31, 2023, of NPI for mitigating and countervailing age-related physical and cognitive decline and associated cerebral degeneration in healthy elderly populations with a mean age of 55 and over. After inventorying the NPI that met our criteria, we divided them into six classes: single-domain cognitive, multi-domain cognitive, physical aerobic, physical non-aerobic, combined cognitive and physical aerobic, and combined cognitive and physical non-aerobic. The ultimate purpose of these NPI was to enhance individual autonomy and well-being by bolstering functional capacity that might transfer to activities of daily living. The insights from this study can be a starting point for new research and inform social, public health, and economic policies. The PRISMA extension for scoping reviews (PRISMA-ScR) checklist served as the framework for this scoping review, which includes 70 studies. Results indicate that medium- and long-term interventions combining non-aerobic physical exercise and multi-domain cognitive interventions best stimulate neuroplasticity and protect against age-related decline and that outcomes may transfer to activities of daily living.

The Role of Physical Activity in Adjunctive Nursing Management of Neuro-Degenerative Diseases among Older Adults: A Systematic Review of Interventional Studies

Neurodegenerative diseases such as dementia and Parkinson's disease pose significant challenges to older adults globally. While pharmacological treatments remain primary, increasing evidence supports the role of non-pharmacological strategies like physical activity in managing these conditions. This systematic review critically evaluates the effectiveness of Nursing based physical activity interventions in improving cognitive function, physical functioning, mobility, and overall quality of life among older adults with neurodegenerative diseases. We conducted a comprehensive search across PubMed, EMBASE, Web of Science, CENTRAL, and other relevant databases, focusing on randomized controlled trials and observational studies that examined the impact of structured physical activity. Our findings from nineteen studies involving 1673 participants indicate that interventions ranging from aerobic exercises, resistance training, to mind-body exercises like Tai Chi and yoga have beneficial effects. Specifically, physical activity was consistently found to enhance cognitive performance, increase mobility, and improve balance and daily living activities, contributing to a better quality of life. However, these benefits vary depending on the type, intensity, and duration of the activity performed. Despite promising results, limitations such as small sample sizes, study heterogeneity, and short-term follow-up periods call for more robust, long-term studies to solidify these findings. This review underscores the potential of tailored physical activity programs as adjunctive therapy in the comprehensive management of neurodegenerative diseases among the elderly population.

Interactions between physical exercise, associative memory, and genetic risk for Alzheimer's disease

The ε4 allele of the APOE gene heightens the risk of late onset Alzheimer's disease. ε4 carriers, may exhibit cognitive and neural changes early on. Given the known memory-enhancing effects of physical exercise, particularly through hippocampal plasticity via endocannabinoid signaling, here we aimed to test whether a single session of physical exercise may benefit memory and underlying neurophysiological processes in young ε3 carriers (ε3/ε4 heterozygotes, risk group) compared with a matched control group (homozygotes for ε3). Participants underwent fMRI while learning picture sequences, followed by cycling or rest before a memory test. Blood samples measured endocannabinoid levels. At the behavioral level, the risk group exhibited poorer associative memory performance, regardless of the exercising condition. At the brain level, the risk group showed increased medial temporal lobe activity during memory retrieval irrespective of exercise (suggesting neural compensatory effects even at baseline), whereas, in the control group, such increase was only detectable after physical exercise. Critically, an exercise-related endocannabinoid increase correlated with task-related hippocampal activation in the control group only. In conclusion, healthy young individuals carrying the ε4 allele may present suboptimal associative memory performance (when compared with homozygote ε3 carriers), together with reduced plasticity (and functional over-compensation) within medial temporal structures.

The Impact of Pandemic-Related Restrictions on Dementia Risk Factors in Older Adults

Adults aged 65+ are at highest risk for severe COVID-19 outcomes, and prior to the distribution of vaccines in the U.S., were strongly advised to quarantine at home to reduce risk of infection. This study examines how COVID-19 restrictions impacted various dementia risk factors and social determinants of health among older adults. Data came from the Systematic Multi-Domain Alzheimer's Risk Reduction Trial, a randomized controlled trial of a multi-domain intervention in higher-risk older adults (aged 70-89). A questionnaire was administered to participants (n = 156; 90.7% response rate) between May 2020 and March 2021. The data show a significant decline in social activity, physical activity, and mood among respondents. Compared to living with others, living alone was associated with worsened physical activity, diet, and subjective memory/thinking, adjusted for sex and age. These results suggest that the COVID-19 pandemic exacerbated several risk factors for dementia in older adults, particularly in those living alone.

A systematic review and meta-analysis of the effects of physical exercise on white matter integrity and cognitive function in older adults

In the context of a globally aging population, exploring interventions that counteract age-related cognitive decline and cerebral structural alterations is paramount. Among various strategies, physical exercise (PE) emerges as a prevalent activity routinely incorporated in many individuals' lives. This systematic review and meta-analysis aims to elucidate the impact of PE on white matter (WM) integrity and cognitive function in older adults. Data from 581 participants, 312 in the PE intervention group, and 269 in the control group were extracted from nine randomized controlled trials (RCTs) retrieved from databases including PubMed, Embase, Web of Science, and the Cochrane Library. The results indicated a significant improvement in white matter (WM) integrity in individuals engaged in PE, as evidenced by enhanced fractional anisotropy (FA) scores (SMD = 0.4, 95% confidence interval (CI) [0.05, 0.75], P = 0.024). The GRADE assessment revealed a moderate risk. However, no significant associations were found between PE and other metrics such as radial diffusivity (RD), mean diffusivity (MD), white matter volume (WMV), hippocampal volume (HV), and cognitive functions (executive function [EF], memory, processing speed). In conclusion, our study emphasizes the potential neurostructural and cognitive functional benefits of physical exercise for the brain health of older adults.

Neurovascular coupling impairment as a mechanism for cognitive deficits in COVID-19

Components that comprise our brain parenchymal and cerebrovascular structures provide a homeostatic environment for proper neuronal function to ensure normal cognition. Cerebral insults (e.g. ischaemia, microbleeds and infection) alter cellular structures and physiologic processes within the neurovascular unit and contribute to cognitive dysfunction. COVID-19 has posed significant complications during acute and convalescent stages in multiple organ systems, including the brain. Cognitive impairment is a prevalent complication in COVID-19 patients, irrespective of severity of acute SARS-CoV-2 infection. Moreover, overwhelming evidence from in vitro, preclinical and clinical studies has reported SARS-CoV-2-induced pathologies in components of the neurovascular unit that are associated with cognitive impairment. Neurovascular unit disruption alters the neurovascular coupling response, a critical mechanism that regulates cerebromicrovascular blood flow to meet the energetic demands of locally active neurons. Normal cognitive processing is achieved through the neurovascular coupling response and involves the coordinated action of brain parenchymal cells (i.e. neurons and glia) and cerebrovascular cell types (i.e. endothelia, smooth muscle cells and pericytes). However, current work on COVID-19-induced cognitive impairment has yet to investigate disruption of neurovascular coupling as a causal factor. Hence, in this review, we aim to describe SARS-CoV-2's effects on the neurovascular unit and how they can impact neurovascular coupling and contribute to cognitive decline in acute and convalescent stages of the disease. Additionally, we explore potential therapeutic interventions to mitigate COVID-19-induced cognitive impairment. Given the great impact of cognitive impairment associated with COVID-19 on both individuals and public health, the necessity for a coordinated effort from fundamental scientific research to clinical application becomes imperative. This integrated endeavour is crucial for mitigating the cognitive deficits induced by COVID-19 and its subsequent burden in this especially vulnerable population.

A review: effects of neurofeedback on patients with mild cognitive impairment (MCI), and Alzheimer's disease (AD)

Neurofeedback training (NFT) is a non-invasive method and has been shown to be effective for attention deficit/hyperactivity disorder (ADHD) and various psychiatric disorders. The aim of this paper is to evaluate the effectiveness of NFT for patients with Mild Cognitive Impairment (MCI) and Alzheimer's disease (AD) or Vascular Diseases (VD), so that we searched research articles from four databases, using the keywords neurofeedback, elderly, MCI, AD, VD, and dementia. As a result, 13 articles were identified regarding the effectiveness of NFT in patients with MCI and AD. Although each study differed in study design, training protocol, electroencephalogram (EEG) electrode placement, and reward and inhibition frequency bands, all were shown to enhance memory, attention, and other cognitive abilities. Additional well-designed, randomized studies with sufficient power are needed to further confirm the effectiveness of NFT.

Trajectories of quality of life and cognition in different multimorbidity patterns: Evidence from SHARE

OBJECTIVES

The study aimed to observe the trajectory of quality of life (QoL) and cognition, and to a analyze the bidirectional association between cognition and QoL for diverse multimorbidity patterns.

METHODS

In total, 16,153 older participants age ≥50 years were included from the Survey of Health, Ageing and Retirement in Europe (SHARE). We used latent class analysis (LCA) to identify multimorbidity patterns in the baseline population. We used linear mixed models (LMM) to examine the trajectory of cognition and QoL in different multimorbidity patterns. A cross-lagged model was employed to analyze the bidirectional association between cognition and QoL in diverse multimorbidity patterns.

RESULTS

Latent class analysis identified four multimorbidity patterns: high and low comorbidity burden (HC and LC), cardiometabolic (CA), and osteoarthrosis (OS). The HC group had the poorest cognitive function and QoL (p for trend < 0.001). Delayed and immediate episodic memory in the OS group declined at a highest rate (p for trend < 0.001). Additionally, a bidirectional association between cognition and QoL was observed. The effect of cognitive function on QoL was relatively stronger than the reverse in the CA and LC groups.

CONCLUSIONS

The rate of decline in cognition and QoL over the time differs in diverse multimorbidity patterns, and patients with four or more chronic diseases should be specially considered. Notably, early monitoring of cognitive function and can help break the vicious cycle between cognitive deterioration and poor QoL in patients with OS or CA diseases.

Frontotemporal disorders: the expansive panoply of syndromes and spectrum of etiologies

Background

Frontotemporal lobe disorders (FTD) are amongst the most common brain neurodegenerative disorders. Their relatively covert, frequently subtle presentations and diverse etiologies, pose major challenges in diagnosis and treatments. Recent studies have yielded insights that the etiology in the majority are due to environmental and sporadic causes, rather than genetic in origin.

Aims

To retrospectively examine the cognitive and behavioral impairments in the veteran population to garner the range of differing syndrome presentations and etiological subcategories with a specific focus on frontotemporal lobe disorders.

Methodology

The design is a retrospective, observational registry, case series with the collection of epidemiological, clinical, cognitive, laboratory and radiological data on people with cognitive and behavioral disorders. Inclusion criteria for entry were veterans evaluated exclusively at Orlando VA Healthcare System, neurology section, receiving a diagnosis of FTD by standard criteria, during the observation period dated from July 2016 to March 2021. Frontotemporal disorders (FTD) were delineated into five clinical 5 subtypes. Demographic, cardiovascular risk factors, cognitive, behavioral neurological, neuroimaging data and presumed etiological categories, were collected for those with a diagnosis of frontotemporal disorder.

Results

Of the 200 patients with FTD, further cognitive, behavioral neurological evaluation with standardized, metric testing was possible in 105 patients. Analysis of the etiological groups revealed significantly different younger age of the traumatic brain injury (TBI) and Gulf War Illness (GWI) veterans who also had higher Montreal Cognitive Assessment (MOCA) scores. The TBI group also had significantly more abnormalities of hypometabolism, noted on the PET brain scans. Behavioral neurological testing was notable for the findings that once a frontotemporal disorder had been diagnosed, the four different etiological groups consistently had abnormal FRSBE scores for the 3 principal frontal presentations of (i) abulia/apathy, (ii) disinhibition, and (iii) executive dysfunction as well as abnormal Frontal Behavioral Inventory (FBI) scores with no significant difference amongst the etiological groups. The most common sub-syndromes associated with frontotemporal syndromes were the Geschwind-Gastaut syndrome (GGS), Klüver-Bucy syndrome (KBS), involuntary emotional expression disorder (IEED), cerebellar cognitive affective syndrome (CCA), traumatic encephalopathy syndrome (TES) and prosopagnosia. Comparisons with the three principal frontal lobe syndrome clusters (abulia, disinhibition, executive dysfunction) revealed a significant association with abnormal disinhibition FRSBE T-scores with the GGS. The regression analysis supported the potential contribution of disinhibition behavior that related to this complex, relatively common behavioral syndrome in this series. The less common subsyndromes in particular, were notable, as they constituted the initial overriding, presenting symptoms and syndromes characterized into 16 separate conditions.

Conclusion

By deconstructing FTD into the multiple sub-syndromes and differing etiologies, this study may provide foundational insights, enabling a more targeted precision medicine approach for future studies, both in treating the sub-syndromes as well as the underlying etiological process.

Land/Water Aerobic Activities: Two Sides of the Same Coin. A Comparative Analysis on the Effects in Cognition of Alzheimer's Disease

 Evidence in the literature indicates that aerobic physical activity may have a protective role in aging pathologies. However, it has not been clarified whether different types of aerobic exercise produce different effects. In particular, these potential differences have not been explored in patients with Alzheimer's disease (AD). The present narrative review has the specific aim of evaluating whether land (walking/running) and water (swimming) aerobic activities exert different effects on cognitive functions and neural correlates in AD patients. In particular, the investigation is carried out by comparing the evidence provided from studies on AD animal models and on patients. On the whole, we ascertained that both human and animal studies documented beneficial effects of land and water aerobic exercise on cognition in AD. Also, the modulation of numerous biological processes is documented in association with structural modifications. Remarkably, we found that aerobic activity appears to improve cognition per se, independently from the specific kind of exercise performed. Aerobic exercise promotes brain functioning through the secretion of molecular factors from skeletal muscles and liver. These molecular factors stimulate neuroplasticity, reduce neuroinflammation, and inhibit neurodegenerative processes leading to amyloid-β accumulation. Additionally, aerobic exercise improves mitochondrial activity, reducing oxidative stress and enhancing ATP production. Aerobic activities protect against AD, but implementing exercise protocols for patients is challenging. We suggest that health policies and specialized institutions should direct increasing attention on aerobic activity as lifestyle modifiable factor for successful aging and age-related conditions.

The Potential of a Stratified Approach to Drug Repurposing in Alzheimer's Disease

Alzheimer's disease (AD) is a complex neurodegenerative condition that is characterized by the build-up of amyloid-beta plaques and neurofibrillary tangles. While multiple theories explaining the aetiology of the disease have been suggested, the underlying cause of the disease is still unknown. Despite this, several modifiable and non-modifiable factors that increase the risk of developing AD have been identified. To date, only eight AD drugs have ever gained regulatory approval, including six symptomatic and two disease-modifying drugs. However, not all are available in all countries and high costs associated with new disease-modifying biologics prevent large proportions of the patient population from accessing them. With the current patient population expected to triple by 2050, it is imperative that new, effective, and affordable drugs become available to patients. Traditional drug development strategies have a 99% failure rate in AD, which is far higher than in other disease areas. Even when a drug does reach the market, additional barriers such as high cost and lack of accessibility prevent patients from benefiting from them. In this review, we discuss how a stratified medicine drug repurposing approach may address some of the limitations and barriers that traditional strategies face in relation to drug development in AD. We believe that novel, stratified drug repurposing studies may expedite the discovery of alternative, effective, and more affordable treatment options for a rapidly expanding patient population in comparison with traditional drug development methods.

The association between type 1 diabetes and exercise/physical activity and prolongation of the honeymoon phase in patients

In type 1 diabetes (T1D), pancreatic beta cells are destroyed by the immune system, causing chronic hyperglycemia and micro and macrovascular complications. However, some people experience a 'honeymoon' phase (or partial remission) after being diagnosed with type 1 diabetes. During this phase, a substantial amount of insulin is still produced by the pancreas, helping to reduce blood sugar levels and the requirement for external insulin. The clinical significance of this phase lies in the potential for pharmacological and non-pharmacological interventions during this time frame to either slow down or arrest beta-cell destruction. Clearly, we need to continue researching novel therapies like immunomodulatory agents, but we also need to look at potentially effective therapies with acceptable side effects that can serve as a complement to the medicines currently being studied. Physical activity and exercise, regardless of its type, is one of the factors its impact on the control of diabetes is being investigated and promising results have been achieved. Although there are still limited reports in this regard, there is some evidence to suggest that regular physical exercise could prolong the honeymoon period in both adults and children. In this review, having described the immune base of type 1 diabetes, we outline the benefits of exercise on the general health of individuals with T1D. Moreover, we centered on the honeymoon and current evidence suggesting the effects of physical activity and exercise on this phase duration.

Greater accelerometer-measured physical activity is associated with better cognition and cerebrovascular health in older adults

OBJECTIVES

Physical activity (PA) may help maintain brain structure and function in aging. Since the intensity of PA needed to effect cognition and cerebrovascular health remains unknown, we examined associations between PA and cognition, regional white matter hyperintensities (WMH), and regional cerebral blood flow (CBF) in older adults.

METHOD

Forty-three older adults without cognitive impairment underwent magnetic resonance imaging (MRI) and comprehensive neuropsychological assessment. Waist-worn accelerometers objectively measured PA for approximately one week.

RESULTS

Higher time spent in moderate to vigorous PA (MVPA) was uniquely associated with better memory and executive functioning after adjusting for all light PA. Higher MVPA was also uniquely associated with lower frontal WMH volume although the finding was no longer significant after additionally adjusting for age and accelerometer wear time. MVPA was not associated with CBF. Higher time spent in all light PA was uniquely associated with higher CBF but not with cognitive performance or WMH volume.

CONCLUSIONS

Engaging in PA may be beneficial for cerebrovascular health, and MVPA in particular may help preserve memory and executive function in otherwise cognitively healthy older adults. There may be differential effects of engaging in lighter PA and MVPA on MRI markers of cerebrovascular health although this needs to be confirmed in future studies with larger samples. Future randomized controlled trials that increase PA are needed to elucidate cause-effect associations between PA and cerebrovascular health.

The effect of acute exercise on attentional control and theta power in young adults

Exercise has a profound impact on one's health, and it is becoming increasingly accepted that exercise also benefits cognitive functioning. Yet, the neural mechanism for which cognitive enhancement occurs is less understood. Therefore, the purpose of our study was to experimentally test whether an acute exercise activity was able to increase theta power and behavioral performance during an executive functioning attentional control task. Participants were randomly assigned to either a stationary-bike exercise or a resting control condition. Thereafter, they completed the Eriksen flanker task, and most participants completed this while EEG data were recorded. From the flanker task data, we demonstrated an interaction effect from both accuracy and reaction time measurements. Importantly, the exercise group was more accurate than the control group in incongruent trials. From the EEG data, theta power was overall higher in the exercise group, especially during the congruent trials, compared to controls. Our results add to the limited but growing body of research that suggests acute exercise produces a general increase in theta power, which in turn may play a role in enhancing cognitive performance. These results, combined with previous research, could have widespread implications in multiple settings such as in the investigation of a biomarker of physical fitness, neurorehabilitation, and in education.

The effects of physical exercise on structural, functional, and biochemical brain characteristics in individuals with chronic whiplash-associated disorder: A pilot randomized clinical trial

BACKGROUND

Exercise for people with whiplash associated disorder (WAD) induces hypoalgesic effects in some, but hyperalgesic effects in others. We investigated the exercise-induced neurobiological effects of aerobic and strengthening exercise in individuals with chronic WAD.

METHODS

Sixteen participants (8 WAD, 8 pain-free [CON]) were randomised to either aerobic or strengthening exercise. MRI for brain morphometry, functional MRI for brain connectivity, and magnetic resonance spectroscopy for brain biochemistry, were used at baseline and after the 8-week intervention.

RESULTS

There were no differences in brain changes between exercise groups in either the WAD or CON group, therefore aerobic and strengthening data were combined to optimise sample size. After the exercise intervention, the CON group demonstrated increased cortical thickness (left parahippocampus: mean difference = 0.04, 95% CI = 0.07-0.00, p = 0.032; and left lateral orbital frontal cortex: mean difference = 0.03, 95% CI = 0.00-0.06, p = 0.048). The WAD group demonstrated an increase in prefrontal cortex (right medial orbital frontal) volume (mean difference = 95.57, 95% CI = 2.30-192.84, p = 0.046). Functional changes from baseline to follow-up between the default mode network and the insula, cingulate cortex, temporal lobe, and somatosensory and motor cortices, were found in the CON group, but not in the WAD group. There were no changes post-exercise in brain biochemistry.

CONCLUSION

Aerobic and strengthening exercises did not exert differential effects on brain characteristics, however differences in structural and functional changes were found between WAD and CON groups. This suggests that an altered central pain modulatory response may be responsible for differential effects of exercise in individuals with chronic WAD.

Exercise therapy to prevent and treat Alzheimer's disease

Alzheimer's disease (AD) is a progressive neurodegenerative disease in the elderly with dementia, memory loss, and severe cognitive impairment that imposes high medical costs on individuals. The causes of AD include increased deposition of amyloid beta (Aβ) and phosphorylated tau, age, mitochondrial defects, increased neuroinflammation, decreased synaptic connections, and decreased nerve growth factors (NGF). While in animals moderate-intensity exercise restores hippocampal and amygdala memory through increased levels of p-AKT, p-TrkB, and p-PKC and decreased levels of Aβ, tau phosphorylation, and amyloid precursor proteins (APP) in AD. Aerobic exercise (with an intensity of 50-75% of VO2 max) prevents hippocampal volume reduction, spatial memory reduction, and learning reduction through increasing synaptic flexibility. Exercise training induces the binding of brain-derived neurotrophic factor (BDNF) to TrkB and the binding of NGF to TrkA to induce cell survival and neuronal plasticity. After aerobic training and high-intensity interval training, the increase of VEGF, angiopoietin 1 and 2, NO, tPA, and HCAR1 in cerebral vessels causes increased blood flow and angiogenesis in the cerebellum, motor cortex, striatum, and hippocampus. In the hippocampus, exercise training decreases mitochondrial fragmentation, DRP1, and FIS1, improving OPA1, MFN1, MFN2, and mitochondrial morphology. In humans, acute exercise as an anti-inflammatory condition causes an acute increase in IL-6 and an increase in anti-inflammatory factors such as IL-1RA and IL-10. Moderate-intensity exercise also inhibits inflammatory markers such as IFN-γ, IL-1β, IL-6, CRP, TNF-α, sTNFR1, COX-2, and NF-κB. Aerobic exercise significantly increases plasma levels of BDNF, nerve growth factor, synaptic plasticity, motor activity, spatial memory, and exploratory behavior in AD subjects. Irisin is a myokine released from skeletal muscle during exercise and protects the hippocampus by suppressing Aβ accumulation and promoting hippocampal proliferation through STAT3 signaling. Therefore, combined exercise training such as aerobic training, strength training, balance and coordination training, and cognitive and social activities seems to provide important benefits for people with AD.

Antidepressant effects of novel positive allosteric modulators of Trk-receptor mediated signaling - a potential therapeutic concept?

BACKGROUND

Major depressive disorder (MDD) is defined as a complex mental disorder which is characterized by a pervasive low mood and aversion to activity. Several types of neurotransmitter systems e.g. serotonergic, glutamatergic and noradrenergic systems have been suggested to play an important role in the origination of depression, but neurotrophins such as brain derived neurotrophic factor (BDNF) have also been implicated in the disease process.

OBJECTIVES

The purpose of this study was to examine the effects of a newly developed class of molecules, characterized as positive allosteric modulators of neurotrophin/Trk receptor mediated signaling (Trk-PAM), on neurotransmitter release and depression-like behavior in vivo.

METHODS

The effect of and possible interaction of neurotrophin/Trk signaling pathways with serotonergic and glutamatergic systems in the modulation of depression-related responses was studied using newly developed Trk-PAM compounds (ACD855, ACD856 and AC26845), as well as ketamine and fluoxetine in the forced swim test (FST) in rodents. Moreover, in vivo microdialysis in freely moving rats was used to assess changes in neurotransmitter levels in the rat.

RESULTS

The results from the study show that several different compounds, which all potentiate Trk-receptor mediated signaling, display antidepressant-like activity in the FST. Moreover, the data also indicate that the effects of both fluoxetine and ketamine in the FST, both used in clinical practice, are mediated via BDNF/TrkB signaling, which could have implications for novel therapies in MDD.

CONCLUSIONS

Trk-PAMs could provide an interesting avenue for the development of novel therapeutics in this area.

Does Therapeutic Exercise Support Improvement in Cognitive Function and Instrumental Activities of Daily Living in Patients with Mild Alzheimer's Disease? A Randomized Controlled Trial

This randomized controlled trial aims to investigate the effect of 12 weeks of therapeutic exercise on cognitive function and daily activities in patients with mild Alzheimer's disease (AD). A total of 171 patients with mild AD from the Amarousion Day Care Center of the Alzheimer Society of Athens and the Athens General Hospital "G. Gennimatas" were randomly divided into three groups. Group A (aerobic and resistance exercise, n = 57), group B (resistance exercise, n = 57), and group C (control group, n = 57). Group A followed a weekly program consisting of 5 days with 30 min walking and 3 days with resistance exercises for about 45 min. Group B followed only a resistance exercise program, the same as group A. Group C did not participate in any exercise program. After the intervention, cognitive function was assessed with the Cognitive Examination-Revised (ACE-R), Trail Making Test A-B (TMT A-B), and Digit Span Test Forward and Backward (DST F-B) and daily activities with the instrumental activities of daily living scale (IADLs). A significant intervention effect was observed for all outcome measures (global cognitive function and instrumental activities of daily living). ANCOVA Bonferroni corrected post hoc tests revealed that the aerobic and resistance group improved compared to the control group on all measurement scales. The resistance group also showed an improvement compared to the control group. No significant effects were found between the aerobic and resistance group and the resistance group in any of the outcome measures.

Effects of Voluntary Physical Exercise on the Neurovascular Unit in a Mouse Model of Alzheimer's Disease

Alzheimer's disease (AD) is the most common neurodegenerative disorder worldwide. Histopathologically, AD presents two pathognomonic hallmarks: (1) neurofibrillary tangles, characterized by intracellular deposits of hyperphosphorylated tau protein, and (2) extracellular amyloid deposits (amyloid plaques) in the brain vasculature (cerebral amyloid angiopathy; CAA). It has been proposed that vascular amyloid deposits could trigger neurovascular unit (NVU) dysfunction in AD. The NVU is composed primarily of astrocytic feet, endothelial cells, pericytes, and basement membrane. Although physical exercise is hypothesized to have beneficial effects against AD, it is unknown whether its positive effects extend to ameliorating CAA and improving the physiology of the NVU. We used the triple transgenic animal model for AD (3xTg-AD) at 13 months old and analyzed through behavioral and histological assays, the effect of voluntary physical exercise on cognitive functions, amyloid angiopathy, and the NVU. Our results show that 3xTg-AD mice develop vascular amyloid deposits which correlate with cognitive deficits and NVU alteration. Interestingly, the physical exercise regimen decreases amyloid angiopathy and correlates with an improvement in cognitive function as well as in the underlying integrity of the NVU components. Physical exercise could represent a key therapeutic approach in cerebral amyloid angiopathy and NVU stability in AD patients.

Role of light walking pace on cognition: Findings from the Maine-Syracuse Longitudinal Study

Moderate- to vigorous intensities of physical activity are recommended for health promotion, including brain health. Regular physical activity is considered a modifiable factor to delay -perhaps prevent- onset of dementias such as Alzheimer's disease. Little is known about the benefits of light physical activity. We analyzed data from a 998 community-dwelling, cognitively unimpaired participants from the Maine-Syracuse Longitudinal Study (MSLS) and investigated the role of light physical activity, defined by walking pace, across two time points. Results revealed light levels of walking pace were associated with higher performance at the first timepoint and less decline by time 2 in the domains of verbal abstract reasoning and visual scanning and tracking, which includes both processing speed and executive function skills. When examining change over time (N = 583), increasing walking pace was associated with less decline at time two for the domains of visual scanning and tracking, working memory, visual spatial ability, and working memory, but not verbal abstract reasoning. These findings highlight the relevance of light physical activity and the need to investigate its contribution to cognitive function. From a public health perspective, this may encourage more adults to adopt a light level of exercise and still reap health benefits.

Life Experience Matters: Enrichment and Stress Can Influence the Likelihood of Developing Alzheimer's Disease via Gut Microbiome

Alzheimer's disease (AD) is a chronic neurodegenerative disease, characterized by the presence of β-amyloid (Aβ) plaques and neurofibrillary tangles (NFTs) formed from abnormally phosphorylated tau proteins (ptau). To date, there is no cure for AD. Earlier therapeutic efforts have focused on the clinical stages of AD. Despite paramount efforts and costs, pharmaceutical interventions including antibody therapies targeting Aβ have largely failed. This highlights the need to alternate treatment strategies and a shift of focus to early pre-clinical stages. Approximately 25-40% of AD cases can be attributed to environmental factors including chronic stress. Gut dysbiosis has been associated with stress and the pathogenesis of AD and can increase both Aβ and NFTs in animal models of the disease. Both stress and enrichment have been shown to alter AD progression and gut health. Targeting stress-induced gut dysbiosis through probiotic supplementation could provide a promising intervention to delay disease progression. In this review, we discuss the effects of stress, enrichment, and gut dysbiosis in AD models and the promising evidence from probiotic intervention studies.

The Additive Benefits of Aerobic Exercise and Cognitive Training Postconcussion: Current Clinical Concepts

Concussion induces the rapid onset of a short-lived neurophysiological disturbance that often results in autonomic nervous system dysfunction. This dysfunction affects both cardiovascular functioning and higher cognitive processing, inducing postconcussion clinical symptoms (somatic, cognitive, or emotional or a combination) and functional disturbances (impaired balance, cognition, and visual-vestibular performance). Current concussion rehabilitation paradigms using aerobic exercise may improve concussion symptoms. Additionally, cognitive training-focused rehabilitation interventions may enhance cognitive function postinjury. Though aerobic exercise and cognitive training-based concussion rehabilitation are successful independently, the multifaceted nature of concussion suggests the potential benefit of integrating both to improve concussion outcomes and clinician implementation. To support this clinical recommendation, we critiqued the existing research in which authors investigated aerobic exercise and cognitive training as postconcussion rehabilitation modalities, identified keys gaps in the literature, and proposed a practical clinical recommendation to integrate both modalities during concussion rehabilitation.

The key values and factors identified by older adults to promote physical activity and reduce sedentary behaviour using co-production approaches: a scoping review

BACKGROUND

Inactivity and sedentary behaviour in older adults adversely impacts physical function, reduces social networks, and could contribute to population healthcare costs. To encourage and support the planning and uptake of physical activity by older adults, it is important to understand what physical activity means to older adults. Therefore, the aim of this scoping review was to collate what older adults have self-identified as the key factors for sustaining and increasing their physical activities.

METHODS

Arksey and O'Malley's Scoping Review framework was used to guide the review process. SCOPUS, ASSIA, PsychINFO and MEDLINE databases were searched. Studies were eligible for inclusion if they were peer-reviewed, the target population were older adults (aged 55 and above), co-production related research approaches were explicitly stated in the methods and there was a focus on design of physical activity interventions or products to support or enhance physical activity. Assets and values important for physical activity were first extracted from included studies and were subsequently thematically analysed. Themes are presented to provide an overview of the literature synthesis.

RESULTS

Sixteen papers were included in the analysis. Data from these papers were gathered via designing interventions or services (n = 8), products (n = 2), 'exergames' (n = 2) or mobile applications (n = 4). Outcomes were varied but common themes emerged across papers. Overarching themes identified by older adults were associated with a desire to increase activity when it was accessible, motivational, and safe. In addition, older adults want to enjoy their activities, want independence and representation, want to stay connected with families and friends, be outdoors, familiarity, activities to be tailored and resulting in measurable/observed progress.

CONCLUSIONS

Population demographics, personal attributes, and life experiences all affect preferences for physical activity. However, the key factors identified by older adults for increasing physical activity were common-even in separate co-production contexts. To promote physical activities in older adults, activities must fundamentally feel safe, provide a sense of social connectedness, be enjoyable and be accessible in terms of cost and ability.

Brain Health Indicators Following Acute Neuro-Exergaming: Biomarker and Cognition in Mild Cognitive Impairment (MCI) after Pedal-n-Play (iPACES)

Facing an unrelenting rise in dementia cases worldwide, researchers are exploring non-pharmacological ways to ameliorate cognitive decline in later life. Twenty older adults completed assessments before and after a single bout of interactive physical and cognitive exercise, by playing a neuro-exergame that required pedaling and steering to control progress in a tablet-based video game tailored to impact executive function (the interactive Physical and Cognitive Exercise System; iPACES v2). This study explored the cognitive and biomarker outcomes for participants with mild cognitive impairment (MCI) and normative older adults after 20 min of pedal-to-play exercise. Neuropsychological and salivary assessments were performed pre- and post-exercise to assess the impact. Repeated-measures ANOVAs revealed significant interaction effects, with MCI participants experiencing greater changes in executive function and alpha-amylase levels than normative older adults; within-group changes were also significant. This study provides further data regarding cognitive effects and potential mechanisms of action for exercise as an intervention for MCI.

Differential remodeling of subcutaneous white and interscapular brown adipose tissue by long-term exercise training in aged obese female mice

Obesity exacerbates aging-induced adipose tissue dysfunction. This study aimed to investigate the effects of long-term exercise on inguinal white adipose tissue (iWAT) and interscapular brown adipose tissue (iBAT) of aged obese mice. Two-month-old female mice received a high-fat diet for 4 months. Then, six-month-old diet-induced obese animals were allocated to sedentarism (DIO) or to a long-term treadmill training (DIOEX) up to 18 months of age. In exercised mice, iWAT depot revealed more adaptability, with an increase in the expression of fatty acid oxidation genes (Cpt1a, Acox1), and an amelioration of the inflammatory status, with a favorable modulation of pro/antiinflammatory genes and lower macrophage infiltration. Additionally, iWAT of trained animals showed an increment in the expression of mitochondrial biogenesis (Pgc1a, Tfam, Nrf1), thermogenesis (Ucp1), and beige adipocytes genes (Cd137, Tbx1). In contrast, iBAT of aged obese mice was less responsive to exercise. Indeed, although an increase in functional brown adipocytes genes and proteins (Pgc1a, Prdm16 and UCP1) was observed, few changes were found on inflammation-related and fatty acid metabolism genes. The remodeling of iWAT and iBAT depots occurred along with an improvement in the HOMA index for insulin resistance and in glucose tolerance. In conclusion, long-term exercise effectively prevented the loss of iWAT and iBAT thermogenic properties during aging and obesity. In iWAT, the long-term exercise program also reduced the inflammatory status and stimulated a fat-oxidative gene profile. These exercise-induced adipose tissue adaptations could contribute to the beneficial effects on glucose homeostasis in aged obese mice.

Sex Differences in Alzheimer's Disease

Reviewing the research presented in this article, it is evident that from an epidemiological perspective, it is important to evaluate the extent to which findings of sex and gender differences in Alzheimer's dementia (AD) are due to differences in longevity, survival bias, and comorbidities. Medical, genetic, psychosocial, and behavioral factors, in addition to hormonal factors, can differentially affect the risk and progression of AD in women versus men. Further, evaluation of sex differences in AD progression and the trajectory of change in cognitive function, neuroimaging, cerebrospinal fluid (CSF), and blood-based biomarkers of AD is needed. Finally, identifying sex differences in AD biomarkers and change across the lifespan is critical for the planning of prevention trials to reduce the risk of developing AD.

Hippocampal blood flow rapidly and preferentially increases after a bout of moderate-intensity exercise in older adults with poor cerebrovascular health

Over the course of aging, there is an early degradation of cerebrovascular health, which may be attenuated with aerobic exercise training. Yet, the acute cerebrovascular response to a single bout of exercise remains elusive, particularly within key brain regions most affected by age-related disease processes. We investigated the acute global and region-specific cerebral blood flow (CBF) response to 15 minutes of moderate-intensity aerobic exercise in older adults (≥65 years; n = 60) using arterial spin labeling magnetic resonance imaging. Within 0-6 min post-exercise, CBF decreased across all regions, an effect that was attenuated in the hippocampus. The exercise-induced CBF drop was followed by a rebound effect over the 24-minute postexercise assessment period, an effect that was most robust in the hippocampus. Individuals with low baseline perfusion demonstrated the greatest hippocampal-specific CBF effect post-exercise, showing no immediate drop and a rapid increase in CBF that exceeded baseline levels within 6-12 minutes postexercise. Gains in domain-specific cognitive performance postexercise were not associated with changes in regional CBF, suggesting dissociable effects of exercise on acute neural and vascular plasticity. Together, the present findings support a precision-medicine framework for the use of exercise to target brain health that carefully considers age-related changes in the cerebrovascular system.

The Association Between Objectively-Measured Physical Activity and Cognitive Functioning in Middle-Aged and Older People Living with HIV

Middle-aged and older people living with HIV (PWH) are at higher risk for cognitive impairment and engage in lower levels of physical activity (PA) than seronegative counterparts. Research examining the association between objectively-measured PA and cognitive function in this population is scarce. This cross-sectional study examined the association between accelerometry-measured PA and cognitive functioning among 75 PWH (mean age 55.63). Light PA was the PA variable with the most consistent associations with cognition, with more minutes per week of light PA (performed in bouts of ≥ 10 min) being associated with better executive function, working memory/attention, and speed of processing performance, adjusted for age and current CD4 count. Findings suggest that although middle-aged and older PWH engage in more light than moderate-to-vigorous PA, light PA may be beneficial to cognition. Longitudinal studies are needed to understand PA dose-response associations with cognitive trajectories, cognitive domain specificity of PA effects, and underlying neural mechanisms of PA.

Associations between physical activity and cognitive dysfunction in older companion dogs: results from the Dog Aging Project

Canine cognitive dysfunction (CCD) is a form of dementia that shares many similarities with Alzheimer's disease. Given that physical activity is believed to reduce risk of Alzheimer's disease in humans, we explored the association between physical activity and cognitive health in a cohort of companion dogs, aged 6-18 years. We hypothesized that higher levels of physical activity would be associated with lower (i.e., better) scores on a cognitive dysfunction rating instrument and lower prevalence of dementia, and that this association would be robust when controlling for age, comorbidities, and other potential confounders. Our sample included 11,574 companion dogs enrolled through the Dog Aging Project, of whom 287 had scores over the clinical threshold for CCD. In this observational, cross-sectional study, we used owner-reported questionnaire data to quantify dog cognitive health (via a validated scale), physical activity levels, health conditions, training history, and dietary supplements. We fit regression models with measures of cognitive health as the outcome, and physical activity-with several important covariates-as predictors. We found a significant negative relationship between physical activity and current severity of cognitive dysfunction symptoms (estimate =  - 0.10, 95% CI: - 0.11 to - 0.08, p < 0.001), extent of symptom worsening over a 6-month interval (estimate =  - 0.07, 95% CI: - 0.09 to - 0.05, p < 0.001), and whether a dog reached a clinical level of CCD (odds ratio = 0.53, 95% CI: 0.45 to 0.63, p < 0.001). Physical activity was robustly associated with better cognitive outcomes in dogs. Our findings illustrate the value of companion dogs as a model for investigating relationships between physical activity and cognitive aging, including aspects of dementia that may have translational potential for Alzheimer's disease. While the current study represents an important first step in identifying a relationship between physical activity and cognitive function, it cannot determine causality. Future studies are needed to rule out reverse causation by following the same dogs prospectively over time, and to evaluate causality by administering physical activity interventions.

Effect of Adding Motorized Cycle Ergometer Over Exercise Training on Balance in Older Adults with Dementia: A Randomized Controlled Trial

BACKGROUND

Falls secondary to balance disturbances have been considered as a burden on health systems in people with dementia aged above 65. Exercise has been increasingly recommended to address such problem and the main challenges being the commitment and supervision of training. The study's aim was to investigate the effect of adding motorized cycle ergometer (MCE) on high intensity functional exercise (HIFE) training on balance and cognition in older adults with dementia.

METHODS

Sixty participants over the age of 65 were randomly allocated into 3 groups, Mo, Ex, and MoEx undergoing, respectively, 50 minutes MCE, HIFE, or combination of both. Sessions were done 3 times per week for 12 weeks. Outcome measures taken before and after study period were Berg Balance Scale (BBS), timed up and go test (TUG), and Mini Mental State Exam (MMSE).

RESULTS

All groups showed significant improvement in BBS scores but not on TUG or MMSE scores. Between group analysis showed no privilege of any used training methods over the other for all measures taken.

CONCLUSIONS

Training with HIFE, MCE, or combination of both is effective in improving balance but not cognition. However, MCE can be an alternative to supervised exercise training in addressing balance.

Barriers and motivators to promotion of physical activity participation for older adults with mild cognitive impairment or dementia: An umbrella review

BACKGROUND

Due to the growing aging population worldwide, cognitive disorders including mild cognitive impairment and dementia is considered a major public health priority. Currently, physical activity is a promising non-drug therapy, however, people with mild cognitive impairment or dementia are more likely to be physically inactive.

OBJECTIVE

To identify the barriers and motivators affecting participation in physical activity in older people with mild cognitive impairment or dementia.

DESIGN

An umbrella review.

METHODS

The Joanna Briggs Institute (JBI) methodology for umbrella reviews was adopted in this study. We searched the PubMed, Embase, Web of science, CINAHL, Cochrane, Scopus and Proquest to identify relevant articles published in English from inception to October 2022. Two researchers independently screened and selected articles against preselected inclusion criteria. Eligible studies were appraised for methodological quality using the combined Meta Quality Appraisal Tool and Assessment of Multiple Systematic Reviews Tool. The Grading of Recommendations Assessment Development and Evaluation- Confidence in the Evidence from Reviews of Qualitative Research tool was employed to determine the confidence level in the evidence of the extracted factors. Theoretical Domain Framework (TDF) was used to map barriers and motivators to physical activity participation. Behavior change techniques (BCTs) was utilized to develop theoretically-informed implementation strategies.

RESULTS

Fourteen relevant reviews (covered over 219 primary studies) were included in this review. A total of 31 factors were identified from the selected reviews. Three factors with the strongest supporting evidence for their influence on participation were: resources/material resources, social support, and perceived competence. According to the behavior change techniques, six implementation strategies (providing supervision, developing tailored interventions, providing safe and promoting environment, helping to increase participants' motivation and adherence, integrating all kinds of social support, and providing suitable staffing) were developed.

CONCLUSIONS

The evidence presented in this umbrella review suggests that a multilevel stakeholder approach and a system-wide viewpoint should be adopted. Through the Theoretical Domain Framework, we not only identified construct factors for future interventions, but also revealed understudied fields in this research areas. This umbrella review generates data that is expected to inform the development of implementation strategies based on the intervention-mapping approach, which will promote participation in physical activity.

REGISTRATION

This study was registered with the PROSPERO (CRD42022371535).

The Effects of Aerobic and Resistance Exercises on the Cognitive and Physical Function of Persons with Mild Dementia: A Randomized Controlled Trial Protocol

Dementia causes deterioration in cognitive and physical functions. The scope of this study is to investigate the effect of different exercise programs on cognitive functions and functionality of persons suffering from mild Alzheimer's disease (AD) by generating information on the exercise types and their parameters. A randomized controlled trial (RCT) will be performed involving aerobic and resistance exercise interventions, taking place both at the sample collection center and at home. Participants will be randomly divided into two different intervention groups and a control group. All groups will be assessed twice; once at baseline and once after 12 weeks. The primary outcome shall comprise the effect of exercise programs on cognitive functions using cognitive testing, such as Addenbrooke's Cognitive Examination-Revisited (ACE-R), Mini Mental State Examination (MMSE), Trail Making Test A-Β (TMT A-B), and Digit Span Test (DST): Digit Span Forward (DSF) and Digit Span Backward (DSB). The effect on functionality will be assessed using the Senior Fitness Test (SFT), Berg Balance Scale (BBS), and Instrumental Activities of Daily Living Scale (IADL) questionnaire. Secondary outcomes include the effect of exercise on depression using the Geriatric Depression Scale-15 (GDS-15), on physical activity using the International Physical Activity Questionnaire (IPAQ), as well as the participants' compliance with the intervention. This study will investigate the possible effect of intervention of different exercise types and the comparison between them. Exercise forms a low-cost and reduced-risk intervention.

Musical and psychomotor interventions for cognitive, sensorimotor, and cerebral decline in patients with Mild Cognitive Impairment (COPE): a study protocol for a multicentric randomized controlled study

BACKGROUND

Regular cognitive training can boost or maintain cognitive and brain functions known to decline with age. Most studies administered such cognitive training on a computer and in a lab setting. However, everyday life activities, like musical practice or physical exercise that are complex and variable, might be more successful at inducing transfer effects to different cognitive domains and maintaining motivation. "Body-mind exercises", like Tai Chi or psychomotor exercise, may also positively affect cognitive functioning in the elderly. We will compare the influence of active music practice and psychomotor training over 6 months in Mild Cognitive Impairment patients from university hospital memory clinics on cognitive and sensorimotor performance and brain plasticity. The acronym of the study is COPE (Countervail cOgnitive imPairmEnt), illustrating the aim of the study: learning to better "cope" with cognitive decline.

METHODS

We aim to conduct a randomized controlled multicenter intervention study on 32 Mild Cognitive Impairment (MCI) patients (60-80 years), divided over 2 experimental groups: 1) Music practice; 2) Psychomotor treatment. Controls will consist of a passive test-retest group of 16 age, gender and education level matched healthy volunteers. The training regimens take place twice a week for 45 min over 6 months in small groups, provided by professionals, and patients should exercise daily at home. Data collection takes place at baseline (before the interventions), 3, and 6 months after training onset, on cognitive and sensorimotor capacities, subjective well-being, daily living activities, and via functional and structural neuroimaging. Considering the current constraints of the COVID-19 pandemic, recruitment and data collection takes place in 3 waves.

DISCUSSION

We will investigate whether musical practice contrasted to psychomotor exercise in small groups can improve cognitive, sensorimotor and brain functioning in MCI patients, and therefore provoke specific benefits for their daily life functioning and well-being.

TRIAL REGISTRATION

The full protocol was approved by the Commission cantonale d'éthique de la recherche sur l'être humain de Genève (CCER, no. 2020-00510) on 04.05.2020, and an amendment by the CCER and the Commission cantonale d'éthique de la recherche sur l'être humain de Vaud (CER-VD) on 03.08.2021. The protocol was registered at clinicaltrials.gov (20.09.2020, no. NCT04546451).

Cognitive interventions for memory and psychological well-being in aging and dementias

The human lifespan has expanded drastically in the last few centuries, due to improvements in sanitation, medicine, and nutrition, but with this increase in longevity comes higher rates of cognitive pathology such as mild cognitive impairment (MCI) and dementia; the latter is estimated to reach more than 75 million people by 2030. Pathology risk is related to measures of executive function, lifestyle factors (e.g., education, occupation, and leisure activities), and cognitive reserve. One way of building cognitive reserve may be to structure the environment to encourage lifelong engagement and learning, and since a pharmacological "cure" for dementia remains elusive, non-pharmacological approaches such as physical activity, social engagement, and cognitive stimulation are becoming increasingly essential to preserving and protecting brain health. Here, we describe our recent research into Reminiscence Therapy (RT) to promote cognitive and psychological function in old age and early dementia. We review the Recall Initiative, which involved brain imaging and behavioral indices of memory pre- and post-RT. We also report results from a pilot study-AIM WARM-in which RT was combined with physical activity, specifically walking, for early-stage dementia. Finally, we outline our future directions for tailored reminiscence interventions in combination with other activities (e.g., yoga and meditation) for different groups, namely early Alzheimer's disease, Semantic Dementia, and older individuals in the prison system.

Beta-band MEG signal power changes in older adults after physical exercise program with and without additional cognitive training

Physical exercise has been considered to be an efficient mean of preserving cognitive function and it influences both the structural and functional characteristics of the brain. It has especially been shown to increase brain plasticity, the capacity to re-structure brain properties in response to interaction, such as cognitive practice. Studies have also examined the potential additive effect of cognitive training on the documented benefit of physical exercise, commonly, however, not at the neural level. We monitored, using magnetoencephalography (MEG), the brain processes associated with executive functions in older individuals who participated in a 12-month randomized controlled trial including two research arms: physical and cognitive training vs physical training alone. Measurements were conducted at 0 months, 6 months, and 12 months. The addition of cognitive training was associated with better performance in the Stroop test that reflects executive control. The extra benefit of cognitive training was also manifested as decreased modulation of beta frequency band (15-25 Hz) especially to difficult distractors. As beta band activity is associated with attentional control, this indicates fewer resources needed to inhibit irrelevant sensory inputs. These results imply an enhancing role of cognitive elements integrated with physical training in improving or maintaining executive functions in older individuals.

A Combination of Caffeine Supplementation and Enriched Environment in an Alzheimer's Disease Mouse Model

A variety of factors has been associated with healthy brain aging, and epidemiological studies suggest that physical activity and nutritional supplements such as caffeine may reduce the risk of developing dementia and, in particular, Alzheimer's disease (AD) in later life. Caffeine is known to act as a cognitive enhancer but has been also shown to positively affect exercise performance in endurance activities. We have previously observed that chronic oral caffeine supplementation and a treatment paradigm encompassing physical and cognitive stimulation by enriched environment (EE) housing can improve learning and memory performance and ameliorate hippocampal neuron loss in the Tg4-42 mouse model of AD. Here, we investigated whether these effects were synergistic. To that end, previous findings on individual treatments were complemented with unpublished, additional data and analyzed in depth by ANOVA followed by Bonferroni multiple comparison post tests. We further evaluated whether plasma neurofilament light chain levels reflect neuropathological and behavioral changes observed in the experimental groups. While a treatment combining physical activity and caffeine supplementation significantly improved learning and memory function compared to standard-housed vehicle-treated Tg4-42 in tasks such as the Morris water maze, no major additive effect outperforming the effects of the single interventions was observed.

A Tutorial for Speech-Language Pathologists: Physical Activity and Social Engagement to Prevent or Slow Cognitive Decline in Older Adults

PURPOSE

This tutorial provides an overview of two behavioral approaches, physical activity and social engagement, to prevent or slow cognitive decline in older adults and to increase awareness in the field of speech-language pathology of the important role that speech-language pathologists (SLPs) play in an interprofessional team working with this population.

METHOD

A review of exercise science, neuroscience, and social science literature was used to synthesize evidence and to outline the impact of physical activity and social engagement on cognition. The following topics were explored: How do exercise and social engagement support cognition? What are modifiable risk factors of dementia? What is the impact of inactivity and isolation on cognition? What is the potential role of the SLP on an interprofessional team focusing on preventive measures for cognitive decline? What is the impact of physical exercise and social engagement on nursing home residents?

RESULTS

Research increasingly points to the critical importance of physical activity and social engagement to prevent cognitive decline in normal aging and to slow cognitive decline associated with mild cognitive impairment and dementia. Research suggests that physical activity maintains or improves memory, attention, executive function, visuospatial function, speed of processing, and general cognitive function. Social engagement has been found to maintain and improve general cognitive function.

CONCLUSIONS

Behavioral interventions are an effective strategy to prevent or slow cognitive decline in the older adult population. SLPs have a role to play on an interprofessional team that works to prevent cognitive decline. By considering factors that play a role in the prevention of cognitive decline, such as physical activity and social engagement, the quality of life and overall health of older adults can be improved. Areas of improvement include memory, attention, executive function, visuospatial function, speed of processing, and general cognitive function.

Fasting for 20 h does not affect exercise-induced increases in circulating BDNF in humans

Intermittent fasting and exercise provide neuroprotection from age-related cognitive decline. A link between these two seemingly distinct stressors is their capability to steer the brain away from exclusively glucose metabolism. This cerebral substrate switch has been implicated in upregulating brain-derived neurotrophic factor (BDNF), a protein involved in neuroplasticity, learning and memory, and may underlie some of these neuroprotective effects. We examined the isolated and interactive effects of (1) 20-h fasting, (2) 90-min light exercise, and (3) high-intensity exercise on peripheral venous BDNF in 12 human volunteers. A follow-up study isolated the influence of cerebrovascular shear stress on circulating BDNF. Fasting for 20 h decreased glucose and increased ketones (P ≤ 0.0157) but had no effect on BDNF (P ≥ 0.4637). Light cycling at 25% of peak oxygen uptake ( V ̇ O 2 peak ${\dot V_{{{\rm{O}}_{\rm{2}}}{\rm{peak}}}}$ ) increased serum BDNF by 6 ± 8% (independent of being fed or fasted) and was mediated by a 7 ± 6% increase in platelets (P < 0.0001). Plasma BDNF was increased from 336 pg l^-1 [46,626] to 390 pg l^-1 [127,653] by 90-min of light cycling (P = 0.0128). Six 40-s intervals at 100% of V ̇ O 2 peak ${\dot V_{{{\rm{O}}_{\rm{2}}}{\rm{peak}}}}$ increased plasma and serum BDNF, as well as the BDNF-per-platelet ratio 4- to 5-fold more than light exercise did (P ≤ 0.0044). Plasma BDNF was correlated with circulating lactate during the high-intensity intervals (r = 0.47, P = 0.0057), but not during light exercise (P = 0.7407). Changes in cerebral shear stress - whether occurring naturally during exercise or induced experimentally with inspired CO₂ - did not correspond with changes in BDNF (P ≥ 0.2730). BDNF responses to low-intensity exercise are mediated by increased circulating platelets, and increasing either exercise duration or particularly intensity is required to liberate free BDNF. KEY POINTS: Intermittent fasting and exercise both have potent neuroprotective effects and an acute upregulation of brain-derived neurotrophic factor (BDNF) appears to be a common mechanistic link. Switching the brain's fuel source from glucose to either ketone bodies or lactate, i.e. a cerebral substrate switch, has been shown to promote BDNF production in the rodent brain. Fasting for 20 h caused a 9-fold increase in ketone body delivery to the brain but had no effect on any metric of BDNF in peripheral circulation at rest. Prolonged (90 min) light cycling exercise increased plasma- and serum-derived BDNF irrespective of being fed or fasted and seemed to be independent of changes in cerebral shear stress. Six minutes of high-intensity cycling intervals increased every metric of circulating BDNF by 4 to 5 times more than prolonged low-intensity cycling; the increase in plasma-derived BDNF was correlated with a 6-fold increase in circulating lactate irrespective of feeding or fasting. Compared to 1 day of fasting with or without prolonged light exercise, high-intensity exercise is a much more efficient means to increase BDNF in circulation.

Effects of exercise therapy on patients with poststroke cognitive impairment: A systematic review and meta-analysis

Objective

To evaluate the effects of exercise therapy on patients with poststroke cognitive impairment and compare the differences in the effect of this method when compared with conventional measures, providing evidence for a more standardized and effective clinical application of exercise therapy.

Methods

A search was conducted using 7 electronic databases, including PubMed, CINAHL, Web of Science, CENTRAL, CNKI, Wanfang, SinoMed, and clinical trials registry platforms for randomized controlled trials concerning exercise therapy on patients with poststroke cognitive impairment. Two researchers independently screened the literature, evaluated the quality, and extracted information. Meta-analysis was carried out using Review Manager 5.4 software.

Results

There were 11 studies with 1,382 patients. Meta-analysis showed that exercise therapy could improve cognitive function [SMD = 0.67, 95% CI (0.31, 1.04), P = 0.0003], motor function [SMD = 1.81, 95% CI (0.41, 3.20), P = 0.01], and the activities of daily living [MD = 8.11, 95% CI (3.07, 13.16), P = 0.002] in patients with poststroke cognitive impairment.

Conclusion

Exercise therapy can not only improve cognitive function in patients with poststroke cognitive impairment but also improve motor function and the activities of daily living. Medical staff should prioritize the management of patients with poststroke cognitive impairment and carry out exercise therapy actively to improve the cognitive function of patients with stroke.

Systematic review registration

https://www.crd.york.ac.uk/prospero/, identifier: CRD42023397553.

Relative importance of potential risk factors for dementia in patients with hypertension

Patients with hypertension are at higher risk for dementia than the general population. We sought to understand the relative importance of various risk factors in the development of dementia among patients with hypertension. This population-based cohort study used data from the Korean National Insurance Service database. Using the Cox proportional hazard model, R2 values for each potential risk factor were calculated to test the relative importance of risk factors for the development of dementia. Eligible individuals were adults 40 to 79 years of age with hypertension and without a history of stroke and dementia between 2007 and 2009. A total of 650,476 individuals (mean age, 60 ± 11 years) with hypertension were included in the analyses. During a mean follow-up of 9.5 years (±2.8 years), 57,112 cases of dementia were observed. The three strongest predictors of dementia were age, comorbidity burden (assessed using the Charlson Comorbidity Index), and female sex (R2 values, 0.0504, 0.0023, and 0.0022, respectively). The next strongest risk factors were physical inactivity, smoking, alcohol consumption, and obesity (R2 values, 0.00070, 0.00024, 0.00021, and 0.00020, respectively). Across all age groups, physical inactivity was an important risk factor for dementia occurrence. In summary, controlling and preventing comorbidities are of utmost importance to prevent dementia in patients with hypertension. More efforts should be taken to encourage physical activity among patients with hypertension across all age groups. Furthermore, smoking cessation, avoiding and limiting alcohol consumption, and maintaining an appropriate body weight are urged to prevent dementia.

Brain insulin resistance and cognitive function: influence of exercise

Exercise has systemic health benefits in people, in part, through improving whole body insulin sensitivity. The brain is an insulin-sensitive organ that is often underdiscussed relative to skeletal muscle, liver, and adipose tissue. Although brain insulin action may have only subtle impacts on peripheral regulation of systemic glucose homeostasis, it is important for weight regulation as well as mental health. In fact, brain insulin signaling is also involved in processes that support healthy cognition. Furthermore, brain insulin resistance has been associated with age-related declines in memory and executive function as well as Alzheimer's disease pathology. Herein, we provide an overview of brain insulin sensitivity in relation to cognitive function from animal and human studies, with particular emphasis placed on the impact exercise may have on brain insulin sensitivity. Mechanisms discussed include mitochondrial function, brain growth factors, and neurogenesis, which collectively help combat obesity-related metabolic disease and Alzheimer's dementia.

Relationships of Physical Activity, Depression, and Sleep with Cognitive Function in Community-Dwelling Older Adults

This cross-sectional, observational study aimed to integrate the analyses of relationships of physical activity, depression, and sleep with cognitive function in community-dwelling older adults using a single model. To this end, physical activity, sleep, depression, and cognitive function in 864 community-dwelling older adults from the Suwon Geriatric Mental Health Center were assessed using the International Physical Activity Questionnaire, Montgomery-Asberg Depression Rating Scale, Pittsburgh Sleep Quality Index, and Mini-Mental State Examination for Dementia Screening, respectively. Their sociodemographic characteristics were also recorded. After adjusting for confounders, multiple linear regression analysis was performed to investigate the effects of physical activity, sleep, and depression on cognitive function. Models 4, 5, 7, and 14 of PROCESS were applied to verify the mediating and moderating effects of all variables. Physical activity had a direct effect on cognitive function (effect = 0.97, p < 0.01) and indirect effect (effect = 0.36; confidence interval: 0.18, 0.57) through depression. Moreover, mediated moderation effects of sleep were confirmed in the pathways where physical activity affects cognitive function through depression (F-coeff = 13.37, p < 0.001). Furthermore, these relationships differed with age. Thus, the associations among physical activity, depression, and sleep are important in interventions for the cognitive function of community-dwelling older adults. Such interventions should focus on different factors depending on age.

Influence of a 12-Month Structured Exercise Program on the Micronutrient-Cognitive Fitness-Physical Association Profiles in Mild Cognitive Impairment

Background

Preventive lifestyle strategies have shown promise to slow down or prevent age-related cognitive decline. However, evidence on the reciprocal longitudinal relationships between nutrition biomarkers and cognitive and physical performance is lacking. Studying nutritional, cognitive, and physical profiles over time may help to overcome this knowledge gap.

Objective

To investigate the relationship of plasma levels of the robust nutritional- and antioxidant defense-related biomarkers carotenoids and tocopherols with both indicators of cognitive and physical performance in persons with mild cognitive impairment (MCI) participating in a structured exercise program.

Methods

Data from 40 participants with MCI of the NeuroExercise study were analyzed. Participants had undergone a blood withdrawal for the analysis of plasma concentrations of six carotenoids, two tocopherols and retinol prior to and after one-year of structured exercise. All participants had undergone a broad spectrum of cognitive and physical performance tests.

Results

Significant associations between lipophilic micronutrients and cognitive/physical measures were observed that were previously found to play a role in cognitive and physical frailty. In particular, lutein, zeaxanthin, and lycopene are confirmed as robust, reliable, and stable indicators of nutritional defense. Importantly, these micronutrients were associated with cognitive measures prior to the physical training program and to a more prominent extent with indicators of motoric function after the physical exercise program.

Conclusion

Specific profiles of lipophilic micronutrients are associated to cognitive performance measures and, especially after a structured exercise program, to indicators of physical performance.

Gait monitoring for older adults during guided walking: An integrated assistive robot and wearable sensor approach

An active lifestyle can mitigate physical decline and cognitive impairment in older adults. Regular walking exercises for older individuals result in enhanced balance and reduced risk of falling. In this article, we present a study on gait monitoring for older adults during walking using an integrated system encompassing an assistive robot and wearable sensors. The system fuses data from the robot onboard Red Green Blue plus Depth (RGB-D) sensor with inertial and pressure sensors embedded in shoe insoles, and estimates spatiotemporal gait parameters and dynamic margin of stability in real-time. Data collected with 24 participants at a community center reveal associations between gait parameters, physical performance (evaluated with the Short Physical Performance Battery), and cognitive ability (measured with the Montreal Cognitive Assessment). The results validate the feasibility of using such a portable system in out-of-the-lab conditions and will be helpful for designing future technology-enhanced exercise interventions to improve balance, mobility, and strength and potentially reduce falls in older adults.

Alzheimer's disease large-scale gene expression portrait identifies exercise as the top theoretical treatment

Alzheimer's disease (AD) is a complex neurodegenerative disorder that affects multiple brain regions and is difficult to treat. In this study we used 22 AD large-scale gene expression datasets to identify a consistent underlying portrait of AD gene expression across multiple brain regions. Then we used the portrait as a platform for identifying treatments that could reverse AD dysregulated expression patterns. Enrichment of dysregulated AD genes included multiple processes, ranging from cell adhesion to CNS development. The three most dysregulated genes in the AD portrait were the inositol trisphosphate kinase, ITPKB (upregulated), the astrocyte specific intermediate filament protein, GFAP (upregulated), and the rho GTPase, RHOQ (upregulated). 41 of the top AD dysregulated genes were also identified in a recent human AD GWAS study, including PNOC, C4B, and BCL11A. 42 transcription factors were identified that were both dysregulated in AD and that in turn affect expression of other AD dysregulated genes. Male and female AD portraits were highly congruent. Out of over 250 treatments, three datasets for exercise or activity were identified as the top three theoretical treatments for AD via reversal of large-scale gene expression patterns. Exercise reversed expression patterns of hundreds of AD genes across multiple categories, including cytoskeleton, blood vessel development, mitochondrion, and interferon-stimulated related genes. Exercise also ranked as the best treatment across a majority of individual region-specific AD datasets and meta-analysis AD datasets. Fluoxetine also scored well and a theoretical combination of fluoxetine and exercise reversed 549 AD genes. Other positive treatments included curcumin. Comparisons of the AD portrait to a recent depression portrait revealed a high congruence of downregulated genes in both. Together, the AD portrait provides a new platform for understanding AD and identifying potential treatments for AD.

The emerging neuroprotective roles of exerkines in Alzheimer’s disease

Despite the extensive knowledge of the beneficial effects of physical exercise, a sedentary lifestyle is still a predominant harm in our society. Sedentarism is one of the major modifiable risk factors for metabolic diseases such as diabetes mellitus, obesity and neurological disorders, including Alzheimer’s disease (AD)–characterized by synaptic failure, amyloid protein deposition and memory loss. Physical exercise promotes neuroprotective effects through molecules released in circulation and mediates the physiological crosstalk between the periphery and the brain. This literature review summarizes the current understanding of the roles of exerkines, molecules released during physical exercise, as systemic and central factors that mediate the beneficial effects of physical exercise on cognition. We highlight the neuroprotective role of irisin—a myokine released from the proteolytic cleavage of fibronectin type III domain-containing protein 5 (FNDC5) transmembrane protein. Lastly, we review evidence pointing to physical exercise as a potential preventative and interventional strategy against cognitive decline in AD.

The Association Between Osteoarthritis with Risk of Dementia and Cognitive Impairment: A Meta-Analysis and Systematic Review

Background: The relationship between osteoarthritis (OA) and risk of dementia and cognitive impairment (CIM) has long been debated; however, uncertainties still persist. Objective: The aim of our present meta-analysis and systematic review was to roundly illuminate the association between OA and the risk of dementia and CIM. Methods: We identified relevant studies by searching PubMed, Embase, and Web of Science up to October 2021. The relative risk (RR) or odds ratio (OR) with 95% confidence interval (CI) were aggregated using random-effects methods. Credibility of each meta-analysis was assessed. Meta-regression and subgroup analyses were conducted. Publication bias was explored using funnel plot. Results: Of 21,925 identified literatures, 8 were eligible for inclusion in the systematic review and 19 observational studies involving 724,351 individuals were included in the meta-analysis. The risk of developing dementia and CIM among OA patients was demonstrated in 11 prospective studies (RR = 1.42, 95% CI = 1.07–1.86, I2 = 98.9%, p <  0.001), 2 retrospective cohort studies (RR = 1.35, 95% CI = 1.19–1.52, I2 = 61.0%, p = 0.109), 3 retrospective case-control studies (OR = 1.21, 95% CI = 0.96–1.53, I2 = 95.2%, p <  0.001), and 4 cross-sectional studies (OR = 1.51, 95% CI = 1.09–2.09, I2 = 75.8%, p = 0.006). Meta-regression analyses did not find any valid moderators. Heterogeneity in subgroup analyses for population age, OA location, year of publication, outcome type, adjusted for BMI, depression, and comorbidity decreased to zero. No significant evidence of publication bias was found. Conclusion: OA associated with an increased risk of dementia and CIM. Effective interventions in OA patients may decrease new incidence of dementia or CIM.