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Dementia

Globally, dementia affects 36 million people and about 10% of people develop the disease at some point in their lives (Who International, 2012).

What is dementia?

Dementia is a brain disease associated with an ongoing, long-term decline of the brain and its abilities. Typical symptoms include:

  • memory loss
  • decline in thinking speed
  • decline in mental agility
  • language problems
  • decline in understanding
  • decline in judgement

This decline in memory and understanding greatly affects a person’s daily functioning (Burns & Iliffe, 2009). Often, people with dementia become uninterested in activities that used to bring them pleasure, and may have emotional outbursts along with changes in personality. They engage less in social situations and often begin to lose their ability to empathise. People with dementia may seem to be agitated, restless and engage in repetitive questioning, all of which are distressing for both the individual and carer.

The Alzheimer’s Society estimates that there are approximately 800,000 people in the UK with dementia, two-thirds of whom are women. It is also estimated that one in three people over 65 will develop dementia at some point, affecting around 1 million people in the UK by 2021 as consequence of an ageing population.

The primary cause of dementia is brain damage as a result of disease or stroke. The area of brain damage influences the type of symptoms an individual will experience. Similarly, dementia is a progressive disease, meaning symptoms get worse over time, although the degree of this varies across individuals.

As dementia progresses, individuals may exhibit a decline in physical function including decreased appetite and decreased oral intake leading to malnutrition and muscle wasting. Incontinence of urine or stool (or both), impaired mobility and gait, and change in sleep patterns. This is because dementia is often a progressive whole-brain disease and affects many different functions of the brain; beyond just memory and calculation.

Risk factors

Increasing age is the biggest risk factor for dementia (Larson et al., 2013). About 3% of people between the ages of 65–74 have dementia, 19% between 75 and 84 and nearly half of those over 85 years of age.

Several other factors contribute to the risk of developing Alzheimer’s disease, including genetic factors, family history, head trauma, midlife hypertension, obesity, diabetes, and hypercholesterolemia (Bendlin et al., 2010). People with Down’s syndrome are also at a particular risk of developing Alzheimer’s disease as they age.

Types of dementia
Dementia is a generic term for a range of different brain diseases. The most common types are outlined below (Burns & Iliffe 2009):

Alzheimer’s Disease – This is the most prevalent type of dementia, making up 50-70% of cases. Damage occurs to brain cells by abnormal proteins surrounding them, leading to a loss of chemical connections between brain cells as they malfunction and sometimes die. The hippocampus is the part of the brain most affected by Alzheimer’s disease. Early symptoms include memory problems, difficulty making decisions, getting lost, forgetting to take medication, word-finding problems and inability to carry out normal day-to-day activities such as cooking. The term Alzheimer’s Disease is sometimes used interchangeably with Alzheimers dementia, but Alzheimers Disease refers to a form of dementia that affects primarily memory, decision making and language.

Vascular dementia – Accounts for approximately 25% of cases of dementia. This type of dementia is caused when brain cells become damaged as a result of the oxygen supply to the brain being reduced. This may occur due to a narrowing or blockage of the blood vessels. Either a large stroke or a series of smaller strokes can lead to blood vessel damage in the brain. Symptoms can be similar to those exhibited in Alzheimer’s dementia and again may depend on where in the brain the strokes have occurred. Depending on the region of the brain affected, patients may develop trouble with planning, carrying out tasks, ‘working memory’ and behaviour modulation, or even motor, gait and urinary disturbances.

Mixed dementia – Some people are diagnosed with more than one type of dementia, and display a mixture of symptoms. For example, it is common for someone to have Alzheimer’s disease and vascular dementia together.

Dementia with Lewy bodies – This occurs in approximately 15% of cases, which involves tiny abnormal structures (Lewy bodies) developing inside brain cells. This disruption eventually leads to cell death. Common symptoms include problems with alertness, difficulties with judging distances and hallucinations. This type of dementia is closely related to Parkinson’s disease, and sometimes can result in disordered movement.

Frontotemporal dementia – Over time, the side parts of the brain are damaged when clumps of abnormal proteins form inside nerve cells, causing them to die. Early symptoms include personality and behaviour changes, with some individuals experiencing speech and memory problems.

As dementia is a progressive disease, an individual will need more care and support over time. However, it is still not understood exactly why some individuals maintain enough cognitive ability to remain independent whilst others need 24/7 care.

Treatment

Whilst no cure for dementia has been developed, considerable research is focused on finding effective treatment to slow the progression of the disease. The ultimate aim is to find a cure. There are known factors that reduce the risk of developing dementia, and further research and eduction on these is important from a public health perspective. Current management options are outlined below.

Counselling and therapy: individuals with dementia, especially in the early stages, may benefit from attending counselling or therapy to enable them to understand the disease and its prognosis. Some individuals with dementia may experience depression, which can be addressed in therapy, for example CBT (Cognitive Behavioural Therapy).

Exercise: some research has found that moderate exercise for individuals with dementia helps with maintaining day to day activities (Forbes, 2013).

Drugs: pharmaceutical treatments may help relieve some of the symptoms of Alzheimer’s or mixed dementia, or they may be taken in an attempt to slow down the decline. Such drugs may temporarily relieve memory problems and improve alertness, level of interest and daily living. When the symptoms of Alzheimer’s disease become more moderate, people may be given memantine (e.g. Ebixa) to help with cognitive abilities and daily living, and ease distressing or challenging behaviours (Birks 2006).  Cholinesterase inhibitors (e.g. donepezil) are often used and may be beneficial in mild to moderate disease, but again often treatment effects vary from individual to individual, and are not without side effects.

In vascular dementia, the underlying conditions of high blood pressure, high cholesterol, diabetes or heart problems are treated in an attempt to slow disease progression.

Prevention

Research indicates that lifestyle changes can help minimise the risk of developing dementia as we age. High blood pressure, lack of physical exercise and smoking increase the risk of developing Alzheimer’s disease and vascular dementia. The physical mechanism here may be in part due to these factors leading to progressive microvascular ischaemic damage to brain tissue. Therefore, it is particularly important that conditions such as diabetes, cardiovascular disease, and high cholesterol are well managed and monitored. Being socially active also seems to lower the risk of developing dementia, for example engaging in cognitively challenging tasks such as puzzles, or visiting friends and family on a regular basis.

A comprehensive review of studies that examined the relationship between food intake and the risk of developing Alzheimer’s disease concluded that high levels of consumption of fats from fish, vegetable oils, non-starchy vegetables, low glycaemic index fruits and a diet low in foods with added sugars might be preventive (Solfrizzi et al., (2011). No one particular food item was highlighted.

In support, more recent research suggests that the adoption of the Mediterranean-type diet is associated with decreased cognitive decline (Panza et al., 2014). Again, this would consist of a balanced diet of fish, fruits and vegetables, low in saturated fats, processed items and refined sugar. It is interesting to note that researchers comment that adoption of such a diet would also reduce the risk of other serious conditions such as stroke, heart disease and cancer.

Watch this space, still more to come on Dementia prevention

 

References

Barnard et al., (2014). Dietary and lifestyle guidelines for the prevention of Alzheimer’s disease. Neurobiology of Aging, 35, Supplement 2, S74–S78.

Bendlin, BB et al. (2010). Midlife predictors of Alzheimer’s disease. Maturitas, 65, pp. 131–137

Birks, J. (2006). Cholinesterase inhibitors for Alzheimer’s disease. The Cochrane database of systematic reviews (1): CD005593.

Burns, A & Iliffe, S. (2009). Dementia. BMJ (Clinical research ed.)338: b75. doi:10.1136/bmj.b75.

Forbes, D. et al. (2013). Exercise programs for people with dementia. The Cochrane database of systematic reviews 12: CD006489.

Iadecola, C. (2013). The pathobiology of vascular dementia. Neuron 80 (4): 844–66.

Larson, EB, Yaffe, K, & Langa, KM (2013). New insights into the dementia epidemic. The New England Journal of Medicine 369 (24): 2275–7.doi:10.1056/nejmp1311405.

Panza, F. et al. (2014). Prevention of Late-life Cognitive Disorders: Diet-Related Factors, Dietary Patterns, and Frailty Models. Current Nutrition Reports, 3(2), pp 110-129.

Solfrizzi et al., (2011) Diet and Alzheimer’s disease risk factors or prevention: the current evidence. Expert Review of Neurotherapeutics, 11, 5.

WHO International (2012). Dementia Fact sheet N°362.  April 2012.

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