Preventing Dementia and Cognitive Decline
Introduction[edit | edit source]
The amount of people suffering from mild cognitive impairment (MCI) or any type of dementia has been constantly on the rise. Around 50 million people suffer from dementia worldwide, with 10 million new cases every year. Although age is the strongest known risk factor for dementia, it is not a normal and inevitable consequence of aging.
The term dementia includes several diseases that are mostly progressive and affect the memory, other cognitive abilities and behaviour. The disease interferes significantly with one's ability to maintain activities of daily living.
- MCI is generally defined as significant memory loss without the loss of other cognitive functions. People with MCI have more memory problems than would be expected from someone at a similar age. People with MCI are able to function independently and do not show other signs of dementia, such as impaired reasoning or judgment.
- Dementia describes a collection of symptoms that are caused by disorders affecting the brain. It is not one specific disease. Dementia affects thinking, behaviour and the ability to perform everyday tasks. Brain function is affected enough to interfere with the person’s normal social or working life.
While there's currently no treatment that can prevent or cure dementia, researchers have identified some factors that may help protect you from cognitive decline.
Protection factors from Cognitive Decline[edit | edit source]
Exercise - has many health benefits. It helps prevent heart disease and type 2 diabetes; lowers the risk for high blood pressure, colon cancer, and breast cancer; and helps relieve insomnia, anxiety, and depression. In addition, it may help ward off cognitive decline and dementia.
- Some studies have shown that engaging in a program of regular exercise improved cognitive function in people who already had memory problems.
- Exercise may be particularly advantageous for people who carry the APOE4 gene variant, which makes people more susceptible to Alzheimer's.
- Sedentary behaviours increase psychological stress and are a greater vascular and metabolic burden.
A Mediterranean-style diet - Emphasizes fruits, vegetables, whole grains, beans, nuts and seeds, and olive oil, and includes moderate amounts of fish, poultry, and dairy products, while limiting red meat. This diet has long been recognized as promoting better cardiovascular health ,lowering the risk of certain cancers, and may protect against cognitive decline.
- Studies point to the protective effect of eg omega-3 polyunsaturated fatty acids and vitamins B6, B12 and folate, antioxidants (vitamin A, C and E) and vitamin D.
- Some older studies suggest that people who consume an average of one alcoholic beverage per day may have a lower risk of dementia. However, experts do not recommend drinking alcohol to prevent cognitive decline. If you enjoy an occasional alcoholic beverage, you should limit your consumption to no more one drink per day.
- In the JAMA study, heavy drinkers—defined as more than four drinks per day or 14 per week for men and more than three drinks per day or seven per week for women—had a 22% higher Alzheimer's risk than the nondrinkers.
- Alcoholic dementia and Wernicke-Korsakoff syndrome are well-known possible consequences of excessive and long-term alcohol consumption.
- There is link between milder forms of MCI and dementia and alcohol abuse, which seems to cause neurotoxicity and neuroinflammation but also affects the brain directly by promoting nutritional deficiency.
Sleep - Getting consistent, good-quality sleep improves overall health and may prevent cognitive decline. We need a certain amount of regular sleep for a variety of essential functions, many of them in the brain. People who regularly sleep less than the recommended seven to eight hours a night score lower on tests of mental function, possibly because learning and memories are consolidated during sleep.
Social contacts - Social interaction can have profound effects on your health and longevity. Strong social connections may be as important as physical activity and a healthy diet. Social activities require you to engage several important mental processes, including attention and memory, which can bolster cognition. Frequent engagement helps strengthen neural networks, slowing normal age-related declines. It may also help strengthen cognitive reserve, which can delay the onset of dementia.
Reduce cardiovascular risk factors - Recent research shows the presence of heart disease and heart failure has been associated with a 27% and 60% increased risk for dementia. The etiologic role of atherosclerosis in Alzheimer's disease is still controversial, but several studies have found correlations between carotid atherosclerosis and Alzheimer's disease. A systematic review by Chang et al, linked asymptomatic carotid stenosis to cognitive dysfunction, suggesting that subclinical changes are involved in cognitive decline when atherosclerosis is present.
Smoking - Tobacco is the major risk factor for cancer, cardiovascular disease and dementia. With the global prevalence of smokers being around 30%, about 14% of all cases of Alzheimer's disease are attributable to smoking. The evidence to the harmful effects on smoking on cognition are strong and show a dose-response effect.
[edit | edit source]
Research has shown a relationship between the development of cognitive impairment and lifestyle-related risk factors that are shared with other noncommunicable diseases. These risk factors include:
- Physical inactivity
- Unbalanced diet
- Tobacco use
- Harmful use of alcohol
- Diabetes Mellitus
- Mid-life hypertension
- Cardiovascular pathology
Other risk modifiable risk factors that are specific to dementia are:
- Mid-life depression
- Low educational attainment
- Social isolation
- Cognitive inactivity
In addition, non-modifiable genetic risk factors exist that increase the risk of developing dementia. It is worth noting that although a family history of dementia is common, the lifetime risk of dementia for relatives of most people with dementia is around 20%, compared with about 10% in the general population.
Economics[edit | edit source]
The financial impact of dementia is significant, both for patients and their families and on a global scale. Families face cost of health and social care and reduction or loss of income. In 2015, the costs for direct medical, social care costs and costs of informal care for dementia were estimated at US$818 billion (1.1% of the GDP). The expected rise in costs for people with dementia worldwide is US$2 trillion by 2030. This total could undermine global social and economic development and overwhelm health and social services.
Prevention[edit | edit source]
The World Health Organization wrote the global action plan on the public response to dementia, in which there lies a big role for the prevention of dementia. Their vision is as follows:
"The vision of the global action plan on the public health response to dementia is a world in which dementia is prevented and people with dementia and their carers live well and receive the care and support they need to fulfil their potential with dignity, respect, autonomy and equality." - WHO, Global Action Plan on the Public Health Response to Dementia 2017-2025 (2017)
As mentioned before, there is a relationship between dementia, MCI and noncommunicable disease and lifestyle-related risk factors. By reducing the level of exposure of both individuals and populations to the modifiable risk factors (beginning in childhood), the capacity to make healthier choices can be strengthened.
The most important measures are:
- Increasing physical activity
- Preventing and reducing obesity
- Promotion of balanced and healthy diets
- Cessation of tobacco use and the harmful use of alcohol
- Social engagement
- Promotion of cognitively stimulating activities and learning
- Prevention and management of diabetes, hypertension and depression
Role for physiotherapy in preventing dementia or MCI[edit | edit source]
When it comes to preventing not only dementia but also other non-communicable lifestyle-related diseases, there is an opportunity and expanding role for physiotherapists to influence the risk factors. Health promotion should be lifespan focussed and can be done through education, advice and exercise.
The physiotherapist could use the intervention mapping (IM) protocol to develop a programme and use Motivational Interviewing to empower the individual's motivation and self-commitment to behavioural change.
A randomised controlled study suggests that action observation (motor-related information available through the visual function) with gait training provides more significant benefits for gait and cognitive performances in the elderly with mild cognitive impairment.
Systematic review studying the biomarkers related to cognition and exercises and cognitive-related effects triggered by exercises in patients with dementia and MCI revealed that:
- exercise intervention could significantly reduce levels of LDL (metabolic marker) and IL-6 (inflammatory biomarker),
- regular aerobic exercise could also decrease the levels of TNF-α (inflammatory biomarker)
- Moderating effects of genotypes showed APOE ε4 non-carriers exhibiting significant improvements in peripheral BDNF (neurotrophic) levels.
However, no significant effect of exercise on Aβ and tau (main neuropathological hallmarks), BDNF, and oxidative stress biomarkers were observed, and more RCTs are required to test the effects of exercise and provide strong evidence for future non-pharmaceutical therapy in patients with cognitive dysfunction.
Focus on the benefits of a healthy lifestyle, and make it a goal for your patient to meet the recommended levels of physical activity:
- Adults aged 18–64 should do at least 150 minutes of moderate-intensity aerobic physical activity throughout the week or do at least 75 minutes of vigorous-intensity aerobic physical activity throughout the week or an equivalent combination of moderate- and vigorous-intensity activity.
- Aerobic activity should be performed in bouts of at least 10 minutes duration.
- For additional health benefits, adults should increase their moderate-intensity aerobic physical activity to 300 minutes per week, or engage in 150 minutes of vigorous-intensity aerobic physical activity per week, or an equivalent combination of moderate- and vigorous-intensity activity.
- Muscle-strengthening activities should be done involving major muscle groups on 2 or more days a week.
Non-Invasive brain Stimulation for Preventing dementia or MCI[edit | edit source]
Non-invasive brain stimulation (NIBS) such as transcranial direct current stimulation,tDCS and transcranial alternating current stimulation, tDCS, has been proven to beneficial in improving cognition. Recently evidence suggests that anodal type of transcranial direct current stimulation to dorsolateral prefrontal cortex and left inferior frontal cortex improves cognition in patient with MCI. Therefore, NIBS may be considered among group of patient with MCI.
Conclusion[edit | edit source]
The vast majority of research tend to support that physical activity is a promising intervention for the prevention and non-pharmacological treatment of dementia. Results vary according to the particular characteristics as type, intensity, frequency and duration.
- Preventing stroke, treating heart diseases, and reducing vascular risk factor burden would therefore represent a powerful strategy to reduce the burden of dementia worldwide.
- All preventive strategies taken in dementia prevention need to be implemented in a life-course approach, such as control of hypertension, obesity and other modifiable risk factors. The results are stronger when these factors are managed in midlife, compared to later life.
- International guidelines on physical activity are evidence-based to reduce the negative consequences of a unhealthy lifestyle and following these guidelines is recommended.
An important take-home message, based on various studies, is that it is never too late to start prevention. Preventive interventions that improve the risk profile even of older individuals can delay the onset of MCI and dementia.
Resources[edit | edit source]
- Global action plan on the public health response to dementia 2017-2025, WHO
- Alzheimer's Disease
- Lewy Body Disease
- Non-Communicable Diseases
References[edit | edit source]
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