Exercise and early-onset Alzheimer's disease: theoretical considerations

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.

Relationship between Associated Neuropsychological Factors and Fall Risk Factors in Community-Dwelling Elderly

This study examined whether neuropsychological factors could affect fall risk factors in the community-dwelling elderly via correlation analysis. A total of 393 older adults (76.69 ± 6.01) participated in this study. Cognitive function, depression, fall efficacy, balance confidence, balance, gait, and muscle strength were evaluated, and the correlation between psychological factors and fall risk factors was analyzed. Additionally, a multiple regression analysis was conducted to determine whether or not there was a significant effect between psychological factors and fall risk factors. Analysis showed that the psychological factors examined were all significantly correlated with the fall risk factors. A correlation analysis between cognitive function and fall risk factors showed that the correlation coefficient of the 6-Meter Walk Test was highest; for depression and fall risk factors, the correlation coefficient of gait speed was highest; for fall efficacy and fall risk factors, the correlation coefficient of the 6-Meter Walk Test was highest; and for confidence in balancing and fall risk factors, the correlation coefficient of the 6-Meter Walk Test was highest. This study suggests that psychological factors affect fall risk factors in the community-dwelling elderly, and a multifaceted approach that includes psychological factors would be helpful in providing interventions for falls.

The Effects of Aerobic Exercise in Patients with Early-Onset Dementia: A Scoping Review

BACKGROUND

Early-onset dementia (EOD) defines all dementia related conditions with an onset before the age of 65 years. EOD places a large and distressing psychological, emotional and financial burden on the individuals themselves and their caregivers. For various reasons, diagnostic and treatment strategies for EOD are very challenging. There is a general agreement that not only the human body but also the mind benefits from physical activity and/or exercise. Especially aerobic exercise has shown to have favorable effects on cognitive functions in healthy older adults, as well as in patients with MCI and dementia. However, there are major differences in age, physical fitness level and clinical presentation between EOD and late-onset dementia. Therefore, one cannot just assume that the same type and intensity of exercise will lead to similar effects in the former population. By conducting this scoping review, the authors aimed to identify the evidence on the effectiveness of aerobic exercise on physical and mental health outcomes in individuals with EOD, display gaps in this context, and formulate related directions for future research.

SUMMARY

There are a number of reasons to assume that aerobic exercise might be extremely valuable within individuals with EOD. However, this scoping review led to the surprising and striking finding that not a single study so far has investigated the effects of physical exercise on cognition, physical performance and feelings of well-being and quality of life in EOD. Although nowadays the disease is increasingly recognized, coping and (non-pharmacological) treatment strategies for EOD are virtually non-existent. Key Messages: Exercise intervention studies in EOD are lacking. With this scoping review the authors hope to inspire researchers in the field for related directions for future research. The potential beneficial effects of aerobic exercise in individuals with EOD should be explored and assessed extensively. Secondarily, decent guidelines for non-pharmacological treatment and coping strategies should be developed, with the aim of supporting people with EOD and their caregivers.

Effects of Physical Activity in Nursing Home Residents with Dementia: A Randomized Controlled Trial

BACKGROUND/AIMS

There is no consensus regarding the optimal nonpharmacological intervention to slow down dementia-related decline. We examined whether physical stimulation interventions were effective in reducing cognitive, physical, mood, and behavioral decline in nursing home residents with dementia.

METHODS

Eighty-seven nursing home residents with dementia were randomly assigned to 3 physical activity interventions: activities of daily living (ADL) training, multicomponent exercise training, or combined multicomponent exercise and ADL training. Outcomes were measured at baseline, and after 3 and 6 months.

RESULTS

A 6-month ADL training benefitted executive functions, physical endurance, and depression among men. Exercise training benefitted only grip strength of participants with mild-to-moderate cognitive impairment. A combined training benefitted functional mobility compared to ADL training, depressive symptoms and agitation compared to exercise training, and physical endurance compared to no physical stimulation.

CONCLUSIONS

ADL training appears to be effective for nursing home residents with moderately severe dementia. It remains unclear whether exercise training is an effective type of stimulation.

The Effects of a Multicomponent Dyadic Intervention With Physical Exercise on the Cognitive Functioning of People With Dementia: A Randomized Controlled Trial

The objective was to evaluate the effects of a multicomponent dyadic intervention on the cognitive functioning of people with dementia living at home in a randomized controlled trial. People with dementia and their family caregivers (n = 111) were randomly assigned to 8 home-based sessions including physical exercise and support or a minimal intervention consisting of monthly written information bulletins and monthly phone calls. Memory, executive functioning (EF), and attention were assessed at baseline, and after 3 (postmeasurement) and 6 months (follow-up). Data were analyzed by using generalized estimating equations (GEE). A small, significant effect was found on attention. No effects were found on memory and EF. Finding only a small significant effect might be explained by the ineffectiveness of the intervention, but also by moderate treatment adherence or a lack of room for improvement because half of the people with dementia were already receiving care in a day care facility.

The effect of physical activity on cognitive function in patients with dementia: A meta-analysis of randomized control trials

Non-pharmacological therapies, such as physical activity interventions, are an appealing alternative or add-on to current pharmacological treatment of cognitive symptoms in patients with dementia. In this meta-analysis, we investigated the effect of physical activity interventions on cognitive function in dementia patients, by synthesizing data from 802 patients included in 18 randomized control trials that applied a physical activity intervention with cognitive function as an outcome measure. Post-intervention standardized mean difference (SMD) scores were computed for each study, and combined into pooled effect sizes using random effects meta-analysis. The primary analysis yielded a positive overall effect of physical activity interventions on cognitive function (SMD[95% confidence interval]=0.42[0.23;0.62], p<.01). Secondary analyses revealed that physical activity interventions were equally beneficial in patients with Alzheimer's disease (AD, SMD=0.38[0.09;0.66], p<.01) and in patients with AD or a non-AD dementia diagnosis (SMD=0.47[0.14;0.80], p<.01). Combined (i.e. aerobic and non-aerobic) exercise interventions (SMD=0.59[0.32;0.86], p<.01) and aerobic-only exercise interventions (SMD=0.41[0.05;0.76], p<.05) had a positive effect on cognition, while this association was absent for non-aerobic exercise interventions (SMD=-0.10[-0.38;0.19], p=.51). Finally, we found that interventions offered at both high frequency (SMD=0.33[0.03;0.63], p<.05) and at low frequency (SMD=0.64[0.39;0.89], p<.01) had a positive effect on cognitive function. This meta-analysis suggests that physical activity interventions positively influence cognitive function in patients with dementia. This beneficial effect was independent of the clinical diagnosis and the frequency of the intervention, and was driven by interventions that included aerobic exercise.

Physical activity program for patients with dementia and their relative caregivers: randomized clinical trial in Primary Health Care (AFISDEMyF study)

BACKGROUND

The aging of the population has led to the increase of chronic diseases, especially dementia and cardiovascular diseases, and it has become necessary for their relatives to dedicate more time in caregiving.The objective in the first phase of this study is to evaluate the effectiveness of a Primary Health Care procedure to increase the physical activity of people with dementia and their relative caregivers. Also the effect on the cognitive state and cardiovascular risk will be assessed.

METHODS/DESIGN

DESIGN

Clinical, multicentric and randomized trial. A simple random sampling to select 134 patients diagnosed with dementia will be carried out. After contacting their relatives, his/her participation in the trial will be requested. A basal assessment will be made and the participants will be asigned to control or intervention group (1:1).

VARIABLES

The main measure will be the assessment of physical activity (podometer and 7-PAR) in patients and caregivers. In patients with dementia: ADAS-cog, functional degree and cardiovascular risk. In caregivers: cardiovascular risk, general health and quality of life.

INTERVENTION

For 3 months, participants will receive instructions to do physical activity with an adapted program. This program will be designed and applied by Primary Health Care professionals in patients with dementia and their caregivers. The control group will receive regular care.

ANALYSIS

An intention-to-treat analysis will be carried out by comparing the observed differences between basal, 6 and 12 months measures. Change in the mean of daily steps assessed with the podometer and 7-PAR will be the main result.

DISCUSSION

If the main hypothesis is confirmed, it could be useful to improve the cognitive state of patients with dementia, as well as the cardiovascular risk of all of them. The results can be good to improve technical features of the devices that register the physical activity in the patients with dementia, and it could facilitate its commercialization.

TRIAL REGISTRATION

Clinical Trials.gov Identifier: NCT02044887.

The occurrence of cerebrovascular atherosclerosis in Alzheimer's disease patients

Background:

Both Alzheimer’s disease (AD) and cerebrovascular atherosclerosis (CA) contributed to dementia in an aged population. Whether they share the same mechanism is unknown.

Aim:

Our goal was to explore the occurrence rates of CA in AD patients.

Method:

Here we examined the degree of CA in different groups of AD patients with contrast angiography. Ninety-three AD patients were recruited to the present study. Contrast computed tomography scanning and contrast angiography were performed for CA analyses.

Result:

We found that the cerebrovascular plaques were common in AD patients, which was partly correlated with the severity of AD (as determined by cognitive decline).

Conclusion:

We concluded that vascular dementia may partly correlate with AD pathology.

Epidemiology of dementias and Alzheimer's disease

BACKGROUND AND AIMS

Global population aging has been one of the defining processes of the twentieth century, with profound economic, political and social consequences. It is driving the current epidemic of dementia, both in terms of its extent and global distribution. The aim of the study was to summarize recent findings relevant to the epidemiological knowledge of dementia and Alzheimer's disease (AD).

METHODS

A narrative mini-review of the literature relevant to the epidemiology of dementia and AD is presented, summarizing important findings and analyzing their implications.

RESULTS

It was estimated that in 2010 there were 36.5 million people living with dementia, with 7.7 million new cases yearly and a new case of dementia every 4 sec. The number of persons living with dementia will nearly double every 20 years. Most of these persons will be living in low- and middle-income countries (LMIC).

CONCLUSIONS

There are a substantial number of people with dementia worldwide and these numbers will continue to increase mainly in LMIC, producing a wide range of impacts. It is important to make dementia a national public health and social care priority worldwide. Recent reviews and meta-analyses have failed to clearly identify a singular causal or preventive pathway for AD that seems to be a multicausal, heterogeneous and age-related condition.

Study protocol: EXERcise and cognition in sedentary adults with early-ONset dementia (EXERCISE-ON)

Background

Although the development of early-onset dementia is a radical and invalidating experience for both patient and family there are hardly any non-pharmacological studies that focus on this group of patients. One type of a non-pharmacological intervention that appears to have a beneficial effect on cognition in older persons without dementia and older persons at risk for dementia is exercise. In view of their younger age early-onset dementia patients may be well able to participate in an exercise program. The main aim of the EXERCISE-ON study is to assess whether exercise slows down the progressive course of the symptoms of dementia.

Methods/Design

One hundred and fifty patients with early-onset dementia are recruited. After completion of the baseline measurements, participants living within a 50 kilometre radius to one of the rehabilitation centres are randomly assigned to either an aerobic exercise program in a rehabilitation centre or a flexibility and relaxation program in a rehabilitation centre. Both programs are applied three times a week during 3 months. Participants living outside the 50 kilometre radius are included in a feasibility study where participants join in a daily physical activity program set at home making use of pedometers. Measurements take place at baseline (entry of the study), after three months (end of the exercise program) and after six months (follow-up). Primary outcomes are cognitive functioning; psychomotor speed and executive functioning; (instrumental) activities of daily living, and quality of life. Secondary outcomes include physical, neuropsychological, and rest-activity rhythm measures.

Discussion

The EXERCISE-ON study is the first study to offer exercise programs to patients with early-onset dementia. We expect this study to supply evidence regarding the effects of exercise on the symptoms of early-onset dementia, influencing quality of life.

Trial registration

The present study is registered within The Netherlands National Trial Register (ref: NTR2124)