Feasibility and Impact of a Multicomponent Exercise Intervention in Patients With Alzheimer's Disease: A Pilot Study

A review of the application of exercise intervention on improving cognition in patients with Alzheimer's disease: mechanisms and clinical studies

Alzheimer's disease (AD) is the most common form of dementia, leading to sustained cognitive decline. An increasing number of studies suggest that exercise is an effective strategy to promote the improvement of cognition in AD. Mechanisms of the benefits of exercise intervention on cognitive function may include modulation of vascular factors by affecting cardiovascular risk factors, regulating cardiorespiratory health, and enhancing cerebral blood flow. Exercise also promotes neurogenesis by stimulating neurotrophic factors, affecting neuroplasticity in the brain. Additionally, regular exercise improves the neuropathological characteristics of AD by improving mitochondrial function, and the brain redox status. More and more attention has been paid to the effect of Aβ and tau pathology as well as sleep disorders on cognitive function in persons diagnosed with AD. Besides, there are various forms of exercise intervention in cognitive improvement in patients with AD, including aerobic exercise, resistance exercise, and multi-component exercise. Consequently, the purpose of this review is to summarize the findings of the mechanisms of exercise intervention on cognitive function in patients with AD, and also discuss the application of different exercise interventions in cognitive impairment in AD to provide a theoretical basis and reference for the selection of exercise intervention in cognitive rehabilitation in AD.

Mass Spectrometry Chromatography-Based Metabolomics: The Effect of Long-Term Aerobic Exercise on Learning Ability and the Metabolism of Intestinal Contents in Mice with Alzheimer's Disease

This study aimed to investigate the effect of long-term aerobic exercise on the metabolism of intestinal contents in APP/PS1 mice was studied using a non-targeted metabolomics technique based on high-performance liquid chromatography-mass spectrometry (HPLC-MS) coupling, providing a theoretical basis for exercise to regulate the metabolism of Alzheimer's disease (AD) organisms. Three-month-old male C57BL/6JNju mice, six wild-type (NC, n = 6); 12 APP/PS1 double transgenic species in total, were randomly divided into AD model (AM, n = 6) and AD model exercise (AE, n = 6) groups. The mice in the NC group were fed naturally, the mice in the AM group were statically placed on a running platform, and the mice in the AE group received a 20-week long-term moderate intensity running platform exercise intervention. Following the exercise intervention, the cecum contents of the mice in each group were collected and analyzed using the HPLC-MS technique, with those meeting both variable important in projection (VIP)> 1.5 and p < 0.05 being screened as differential metabolites. A total of 32 different metabolites were detected between the AM and NC groups, with 19 up-regulated in the AM group such as phosphatidic acid (PA) (18:4(6Z,9Z,12Z,15Z)/21:0) and 13 down-regulated in the AM group, such as 4,8-dimethylnonanoyl, compared to the NC group; 98 different metabolites were found between the AM and AE groups, 41 of which were upregulated such as Lyso phosphatidylcholine (LysoPC) and 57 of which were downregulated compared to the AM group such as Phosphatidylinositol (PI). The regulation of linoleic acid metabolism, glycerophospholipid metabolism, bile secretion, phenylalanine metabolism, and other pathways was predominantly regulated by nine metabolites, which were subsequently identified as indicators of exercise intervention to enhance metabolism in AD mice. The metabolomic technique can identify the metabolic problems of intestinal contents in AD mice and initially screen the biomarkers of exercise to improve the metabolic disorders in AD. These findings can help us better understand the impact of aerobic exercise on AD metabolism.

Feasibility of a Modified Otago Exercise Program for Older Adults With Cognitive Vulnerability

Cognitive vulnerability, that is, clinically significant symptoms of dementia, depression, or delirium, puts older adults at high risk for physical inactivity and falls. Programs addressing activity and falls are needed. The purpose was to determine feasibility of an in-home, modified, Otago Exercise Program (OEP) for those with cognitive vulnerability, based on acceptability (retention and adherence), safety (pain intensity and falls), and potential positive effects (change in short physical performance battery (SPPB)). This secondary analysis of a randomized controlled trial included 80 participants who received the OEP; 64 completed it, 48% had depression, 22% had dementia, and 30% had a combination dementia/depression/delirium. Adherence to home exercise was low to moderate; pain was stable over 16 weeks; 31% of participants reported falls unrelated to OEP. SPPB increased from 6.95 to 7.74 (p < .01); age by time and diagnosis by time interactions were not significant. The modified OEP shows promising feasibility for older adults with cognitive vulnerability.

Ketones: potential to achieve brain energy rescue and sustain cognitive health during ageing

Alzheimer’s disease (AD) is the most common major neurocognitive disorder of ageing. Although largely ignored until about a decade ago, accumulating evidence suggests that deteriorating brain energy metabolism plays a key role in the development and/or progression of AD-associated cognitive decline. Brain glucose hypometabolism is a well-established biomarker in AD but was mostly assumed to be a consequence of neuronal dysfunction and death. However, its presence in cognitively asymptomatic populations at higher risk of AD strongly suggests that it is actually a pre-symptomatic component in the development of AD. The question then arises as to whether progressive AD-related cognitive decline could be prevented or slowed down by correcting or bypassing this progressive ‘brain energy gap’. In this review, we provide an overview of research on brain glucose and ketone metabolism in AD and its prodromal condition – mild cognitive impairment (MCI) – to provide a clearer basis for proposing keto-therapeutics as a strategy for brain energy rescue in AD. We also discuss studies using ketogenic interventions and their impact on plasma ketone levels, brain energetics and cognitive performance in MCI and AD. Given that exercise has several overlapping metabolic effects with ketones, we propose that in combination these two approaches might be synergistic for brain health during ageing. As cause-and-effect relationships between the different hallmarks of AD are emerging, further research efforts should focus on optimising the efficacy, acceptability and accessibility of keto-therapeutics in AD and populations at risk of AD.

Different Exercise Time on 5-HT and Anxiety-like Behavior in the Rat With Vascular Dementia

BACKGROUND

Previous studies have demonstrated that pre-exercise suppresses anxiety-like behavior, but the effects of different exercise times on vascular dementia induced anxiety-like behavior have not been well investigated.

OBJECTIVE

The present study aims to investigate the underlying neurochemical mechanism of different pre-vascular-dementia exercise times on 5-HT and anxiety-like behavior in rats with vascular dementia.

METHODS

32 Sprague-Dawley (SD) rats were randomly divided into 4 groups: sham group (S group, n = 8), vascular dementia group (VD group, n = 8), 1-week physical exercise and vascular dementia group (1WVD group, n = 8), and 4 weeks physical exercise and vascular dementia group (4WVD group, n = 8). 1 week and 4 weeks of voluntary wheel running were used as pre-exercise training. The vascular dementia model was established by bilateral common carotid arteries occlusion (BCCAo) for 1 week. But bilateral common carotid arteries were not ligated in the sham group. The level of hippocampal 5-HT was detected with in vivo microdialysis coupled with high-performance liquid chromatography (MD-HPLC). Elevated plus maze (EPM), open field (OF), and light/dark box test were used to test anxiety-like behavior.

RESULTS

Compared with the C group, the hippocampal 5-HT was significantly decreased in the VD group after 1 week of ligated operation. The hippocampal 5-HT levels in 1WVD and 4WVD groups were substantially higher than the level in the VD group. The hippocampal 5-HT level has no significant difference among C, 1WVD, and 4WVD. Behavioral data suggested that the rats in the VD group developed obvious anxiety-like behavior after 1 week of ligation surgery. Still, the rats in 1WVD and 4WVD groups did not show significant anxiety-like behavior.

CONCLUSION

Both 1 week and 4 weeks of voluntary running wheel exercise can inhibit the anxiety-like behavior in rats with vascular dementia by upregulating 5-HT levels in the hippocampus in the VD model.

Effectiveness of Multicomponent Exercise Interventions in Older Adults With Dementia: A Meta-Analysis

BACKGROUND AND OBJECTIVES

Multicomponent training (MT) combines aerobic, strength, postural, and balance exercises and may be a promising intervention strategy for dementia. This meta-analysis study aims to systematize evidence concerning the effectiveness of MT in physical fitness, cognition, and functionality on activities of daily living (ADL) in older adults with dementia and to identify moderation patterns regarding training variables.

RESEARCH DESIGN AND METHODS

4 databases were systematically searched to locate potential trials through March 2019. A total of 2,312 records were identified and a final set of 17 manuscripts reviewed; of these, 6 satisfied all eligibility criteria.

RESULTS

Samples sizes ranged from 27 to 170 participants; MT programs lasted between 4 weeks and 12 months, took place from a daily basis to twice a week, and sessions ranged from 30 to 60 min. The TESTEX scale was used to analyze the methodological quality, and the funnel plots to assess the risk of bias. This meta-analysis revealed that MT interventions benefit older adults with dementia regarding ADL performance (effect size = 0.313 [0.16-0.46]; p < .01), but the evidence was not sufficiently robust to determine the effectiveness of MT on cognitive function and physical fitness, particularly, on agility.

DISCUSSION AND IMPLICATIONS

MT may be an important nonpharmacological strategy to enhance ADL functionality on older adults with dementia. Findings suggest that long-term interventions are more prevalent than high-frequency and longer duration exercise sessions. Further evidence is needed for acknowledging its benefits in specific cognitive abilities and physical fitness. This meta-analysis is registered in PROSPERO (no. CRD42020141545).

Contribution of a multicomponent intervention on functional capacity and independence on activities of daily living in individuals with neurocognitive disorder

BACKGROUND

To examine the effects of a 6-month multicomponent (MT) exercise intervention in the functional capacity and ability to independently perform activities of daily living (ADL) of individuals diagnosed with neurocognitive disorder (NCD).

METHODS

A quasi-experimental controlled trial with a parallel design study was conducted in multicentered community-based settings. Forty-three individuals (N Female: 30) were allocated to an exercise group (EG; N: 23; mean 75.09, SD = 5.54 years) or a control group (CG; N:20; mean 81.90, SD = 1.33 years). The EG engaged in a 6-month MT program (60-min sessions, twice a week). Exercise sessions were divided into a warm-up, specific training (e.g., coordination and balance, lower and upper body strength, and aerobics), and cool down. Lower body function, mobility, and gait speed were evaluated through Short Physical Performance Battery (SPPB), Timed-Up and Go test (TUG) and 6-Meter Walk test, respectively. The Barthel Index (BI) was administered to assess individuals' ADL independence. Evaluations were performed before and after the 6-month intervention.

RESULTS

Linear Mixed Models revealed a statistically significant interaction (time X group) effect factor on SPPB (B = 2.33, 95% CI: 1.39-3.28, p < 0.001), TUG (B = - 11.15, 95% CI: - 17.23 - - 5.06, p = 0.001), and 6-Meter Walk test (B = 0.17, 95% CI: 0.08-0.25, p < 0.001). No differences between groups or assessment moments were found in the ability of individuals to independently perform ADL.

CONCLUSIONS

The 6-month MT exercise intervention improves the functional capacity of older adults living with NCD.

TRIAL REGISTRATION

ClinicalTrials.gov - identifier number NCT04095962 ; retrospectively registered on 19 September 2019.

The Beneficial Role of Exercise on Treating Alzheimer's Disease by Inhibiting β-Amyloid Peptide

Alzheimer's disease (AD) is associated with a very large burden on global healthcare systems. Thus, it is imperative to find effective treatments of the disease. One feature of AD is the accumulation of neurotoxic β-amyloid peptide (Aβ). Aβ induces multiple pathological processes that are deleterious to nerve cells. Despite the development of medications that target the reduction of Aβ to treat AD, none has proven to be effective to date. Non-pharmacological interventions, such as physical exercise, are also being studied. The benefits of exercise on AD are widely recognized. Experimental and clinical studies have been performed to verify the role that exercise plays in reducing Aβ deposition to alleviate AD. This paper reviewed the various mechanisms involved in the exercise-induced reduction of Aβ, including the regulation of amyloid precursor protein cleaved proteases, the glymphatic system, brain-blood transport proteins, degrading enzymes and autophagy, which is beneficial to promote exercise therapy as a means of prevention and treatment of AD and indicates that exercise may provide new therapeutic targets for the treatment of AD.

"Body & Brain": effects of a multicomponent exercise intervention on physical and cognitive function of adults with dementia - study protocol for a quasi-experimental controlled trial

BACKGROUND

Dementia is a leading cause of death and disability that was declared as one of the greatest health and social care challenges of the twenty-first century. Regular physical activity and exercise have been proposed as a non-pharmacological strategy in disease prevention and management. Multicomponent Training (MT) combines aerobic, strength, balance and postural exercises and might be an effective training to improve both functional capacity and cognitive function in individuals with dementia (IwD). Nevertheless, data on the effects of MT in IwD are still limited and the extent to which IwD can retain improvements after an exercise intervention still needs to be elucidated. The aim of "Body & Brain" study is to investigate the effects of a 6-month MT intervention and 3-month detraining on the physical and cognitive function of IwD. Additionally, we aim to explore the impact of this intervention on psychosocial factors and physiologic markers related to dementia.

METHODS

This study is a quasi-experimental controlled trial using a parallel-group design. The study sample consists of community-dwelling individuals aged ≥60 years who are clinically diagnosed with dementia or major neurocognitive disorder. Participants will be either allocated into the intervention group or the control group. The intervention group will participate in MT biweekly exercise sessions, whereas the control group will receive monthly sessions regarding physical activity and health-related topics for 6 months. The main outcomes will be physical function as measured by the Short Physical Performance Battery (SPPB) and cognitive function evaluated using the Alzheimer Disease Assessment Scale - Cognitive (ADAS-Cog) at baseline, after 6-months and 3-months after the end of intervention. Secondary outcomes will be body composition, physical fitness, daily functionality, quality of life, neuropsychiatric symptoms and caregiver's burden. Cardiovascular, inflammatory and neurotrophic blood-based biomarkers, and arterial stiffness will also be evaluated in subsamples.

DISCUSSION

If our hypothesis is correct, this project will provide evidence regarding the efficacy of MT training in improving physical and cognitive function and give insights about its impact on novel molecular biomarkers related to dementia. This project may also contribute to provide guidelines on exercise prescription for IwD.

TRIAL REGISTRATION

ClinicalTrials.gov - identifier number NCT04095962 ; retrospectively registered on 19 September 2019.

The Neuroprotective Effects of Exercise on Cognitive Decline: A Preventive Approach to Alzheimer Disease

Alzheimer's disease (AD) is a progressive disorder that causes brain cells to slowly degenerate and die. This leads to a continuous decline in thinking, behavioral and social skills that disrupts a person's ability to function independently. AD is the most common cause of dementia globally. Neuroinflammation caused by intracellular neurofibrillary tangles and extracellular amyloid deposits leads to atrophy of brain cells especially the hippocampus, which is associated with memory formation. This atrophy leads to dementia and cognitive decline. Among the many preventive factors being studied, exercise is thought to play a vital role in not only preventing the pre-clinical stage of AD but also slowing the clinical progression of AD. It is also deployed as a treatment option for late-stage AD along with pharmacological treatment options. Various studies and clinical trials in both human and animal models are of the opinion that exercise slows the onset and progression of cognitive decline in AD patients. Some studies suggest that this effect is due to a decrease in neurofibrillary tangles and amyloid deposits in brain parenchyma. Others suggest that exercise causes an increase in angiogenesis, neurogenesis, and synaptogenesis mainly due to an increase in blood flow, brain-derived neurotrophic factor (BDNF), insulin-like growth factor 1 (IGF-1), hormones, and second messengers. 

Home-Based Physical Activity Programs for People With Dementia: Systematic Review and Meta-Analysis

Background and Objectives

Physical activity has the potential to improve health outcomes in people with dementia, namely when living at home. However, the knowledge about home-based physical activity for this population is scarce. Thus, we aim to identify and synthesize the effects of home-based physical activity for people with dementia.

Research Design and Methods

A systematic review was conducted. Quality of studies was assessed using the Delphi List. Effect sizes (ES) were calculated with MetaXL 2.0. A meta-analysis was conducted for the Mini-Mental Status Examination (MMSE), Neuropsychiatric Inventory (NPI), Cornell Scale for Depression in Dementia, Alzheimer’s Disease Cooperative Study Group Activities of Daily Living Scale (ADCS-ADL), Functional Reach test, Timed Up and Go (TUG) test, Short Physical Performance Battery, Dementia Quality of Life, NPI Caregivers subscale and Zarit Burden Interview (ZBI).

Results

Sixteen randomized controlled trials were included. Most were of high quality and published after 2015. A large heterogeneity of interventions was found. Meta-analysis showed significant results in MMSE (ES = 0.71, 95% CI 0.43, 0.99), NPI (ES = −0.37, 95% CI −0.57, −0.17), ADCS-ADL (ES = 0.80, 95% CI 0.53, 1.07), Functional Reach test (ES = 2.24, 95% CI 1.80, 2.68), TUG test (ES = −2.40, 95% CI −2.84, −1.96), NPI Caregivers subscale (ES = −0.63, 95% CI −0.94, −0.32), and ZBI (ES = −0.45, 95% CI −0.77, −0.13). Few minor adverse events and high adherence to intervention were found.

Discussion and Implications

Home-based physical activity seems safe and effective in delaying cognitive function decline and improving changes in behavioral and psychological symptoms of dementia, activities of daily living, health-related physical fitness, and carer’s burden in people with dementia living at home.