Ageing Population Alzheimers And Parkinsons Disease Biology Essay

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The UK population is ageing. The latest figures show that currently there are 10 million people over 65 in the UK, this is set to grow by around 5 million in the next 20 years and by 2050 there will be nearly 20 million elderly people in the UK (1). With this increasing number of people out of work and of increasing risk of age related diseases this puts an immense strain on the UK's economy with more people needing state pensions and healthcare. Two age related diseases that require a lot of management and treatment are Alzheimer's disease and Parkinson's disease. As the population ages these diseases will become more prevalent and this will affect the healthcare given to the sufferers.

Alzheimer's Introduction

Alzheimer's disease is a degenerative brain disease that affects all sections of the brain leading to dementia and ultimately death. It is the most common form of dementia accounting for 60% to 80% of all cases reported. The first case of Alzheimer's disease was identified in 1906 by German physician Alois Alzheimer in a patient who presented with symptoms such as reduced comprehension and memory, aphasia, paranoia, unpredictable behaviour and disorientation (2). Dr Alzheimer, upon dissecting his patient Auguste D.'s brain, found some striking features notably shrinkage of the whole brain, a build of protein deposits between the neurons known as amyloid plaques and neurofibrillary tangles which are tangles inside of the nerve cells. These features are now known as the hallmarks of Alzheimer's disease although it is still unknown whether these features are the cause of Alzheimer's disease or are features of the disease's progression.

Parkinson's Introduction

Parkinson's disease is a progressive degenerative brain disease that affects certain sections of the brain and is of importance to older people. Parkinson's disease mainly affects people aged 50 and over but in some cases can affect people between 20 and 50. The main symptoms of Parkinson's disease are uncontrollable shaking in a body part also known as a tremor, a slowing of movement or bradykinesia and stiff muscles. However not all sufferers are affected by all these symptoms and some may have others and to varying degrees. Parkinson's was first described by James Parkinson in his 1817 paper entitled "An Essay on the Shaking Palsy" (3) in which Parkinson observed 6 cases all of which showed the classic symptoms of Parkinson's disease as it would become to be known. The risk of developing Parkinson's disease increases dramatically with age with both the incidence and prevalence increasing with age. The prevalence of Parkinson's disease in the overall UK population is around 200 per 100,000 whereas in the over 80's this prevalence is around 1 in 50 showing a sharp increase (4).


Alzheimer's disease is extremely complex and in over 100 years of research into the disease no definite cause is known. There are however several risk factors associated with it such as heavy metal, such as mercury, exposure, a genetic predisposition, age, head injury and also vascular risk factors such as hypertension. It is likely that the disease is caused by many of these rather than one individual cause. Alzheimer's disease is not by definition a genetic disorder, meaning that if a direct family member suffers from it, it will not necessarily be passed on. However, there is an increased risk of the disease sometimes as high as 2 to 3 times more likely as someone without a positive family history (5). It is age that is the largest risk factor for Alzheimer's disease; it affects 1 in 14 people over the age of 65 and 1 in 6 over the age of 80 suggesting an increased risk as one gets older. It is not purely a disease that affects older people however with around 17,000 people under the age of 65 living with Alzheimer's in the UK (6). It has also been shown that a head injury can increase the risk of developing Alzheimer's disease. Studies of boxers who suffered from pugilistica dementia found that the beta-amyloid plaques associated with Alzheimer's were present but not in all cases (7). Other studies have found a positive association with severe head trauma and Alzheimer's with some studies claiming that it can up to quadruple the chance of developing the disease depending on the severity of the trauma (8).

Although still not completely understood, it is known what causes the symptoms of Parkinson's disease. The death of dopamine producing cells in an area of the brain called the substantia nigra, named because of the high concentration of melanin in this area causing it to appear darker. The pars compacta section of the substantia nigra which is affected by Parkinson's disease is responsible for supplying the striatum with dopamine. The reason for this cell death however is unknown. Much like Alzheimer's disease there are several risk factors that may or may not increase ones chance of developing Parkinson's. These risk factors include personality traits, environmental factors and genetics. Personality traits such as those who live a strict lifestyle, occasionally depressive or are shy may be linked to greater risk of developing Parkinson's, however it is unclear whether these traits are an actual risk or that these traits lead to dopamine deficiency being noticed earlier. Herbicides and pesticides are some of the environmental factors that may heighten the risk of Parkinson's and Parkinson's is more common in farming communities. Other organisms linked to the causation of Parkinson's are HIV, Nocardia asteroides, Japanese encephalitis virus, Influenza A virus, Helicobacter pylori, Toxoplasma gondii and Prion protein (9).


Alzheimer's disease has many stages in its ultimately fatal course. In its earliest stages the disease shows no symptoms, no person including a qualified physician would recognise the individual with having the disease. As time progresses, forgetfulness will increase and the individual will perhaps misplace simple items such as keys but may put this down to purely getting older, this is known as early disease. As the disease progresses into mild disease the memory lapses will become more pronounced, this will include forgetting birthdays and appointments, having to read things over and over again, forgetting when the individual last ate and paying bills. Other signs of mild disease are losing the ability to learn new things easily, struggling to hold a conversation and using the wrong words in a sentence. The disease then progresses into moderate disease; this is where familiar items and people soon become unfamiliar to the individual. Family members may not be recognised and tasks that have multiple steps become increasingly difficult, conversations with the individual will become harder and they may mix up their words and also simple maths will become very difficult. As well as these symptoms behavioural changes become apparent such as becoming suspicious of family members, becoming agitated and sometimes losing impulse control. The final stage of Alzheimer's disease is severe disease, this where the individual begins to lose motor function and will probably lose the ability to walk, talking becomes harder and also weight loss occurs as the individual forgets to eat and sometimes forgets to swallow. Other signs of severe disease may include incontinence, ulcers and pressure sores from being bed ridden which may lead to systemic infection and possible pneumonia and bladder infections until finally the disease runs its course leading to death.

Similarly to Alzheimer's, the early signs of Parkinson's may simply be ignored and shrugged off. However there are several signs of Parkinson's that can be spotted and these may include bradykinesia, a resting tremor, a stooped or hunched posture, constipation, a masked face whereby the individual will have a serious or angry looking expression and possibly an impaired sense of smell. Other possible symptoms may include sleeping trouble, handwriting becomes small and speech becomes soft and quiet. The parkinsonian tremor is the most obvious and well known effect of the disease. It is a result of involuntary muscle contraction causing the limbs to shake; it affects 70% of Parkinson disease sufferers. As well as these motor symptoms there are an extensive range of non-motor symptoms caused by Parkinson's disease. These may include depression, anxiety, dementia, hallucinations, impulse control disorders, fatigue and also Parkinsonian pain. There are similarities in some of the symptoms of both Alzheimer's and Parkinson's, most notably dementia and many of the mental symptoms. There are 3 main classifications of the stages of Parkinson's disease. Stage one or mild Parkinson's may interrupt the individuals daily lives but of no more than an annoyance so a tremor may be annoying rather than debilitating and medication should be able to control the symptoms relatively well. Moderate Parkinson's becomes more of a hindrance and more effort is required in controlling the disease, bradykinesia becomes more pronounced and paradoxical akinesia also known as freezing episodes become apparent. Drugs and regular exercise can help with this stage of the disease. The final stage of the disease is severe Parkinson's disease, here the individual has great difficulty walking and will probably become wheelchair bound, there will be difficulty talking and cognitive impairment becomes more pronounced (4).

Pharmacological Treatment

The treatments for Alzheimer's remain somewhat experimental with not one treatment being seen as the most effective or the standard treatment for the disease. Cholinesterase inhibitors are the first choice when using a pharmacological treatment. The cholinesterase inhibitors increase the amount of acetylcholine in the brain thus allowing the nerve cells to respond more efficiently with each other. Other pharmacological treatments include memantine which works by reducing the amount of glutamate present in the brain and in theory slows down the damage caused by Alzheimer's (5).

The main treatment for Parkinson's disease is levodopa which is a drug that replaces the lost dopamine caused by the disease; other treatments for Parkinson's include dopamine agonists which activate the dopamine receptors in the brain and also MAO-B inhibitors which reduce the breakdown of dopamine. All of these drugs target the brain to try and keep as much dopamine as possible to try to slow the onset of the disease (4).

Alzheimer's and Parkinson's Diseases Effects on an Ageing Population

As the population ages these diseases will become more and more prominent and in turn become more and more expensive to treat. As more people live well past 80 years old the risk for both of these disease increases very quickly which means a lot of the population will suffer from them. Both of these conditions in their later stages require very intensive care as both Alzheimer's and Parkinson's sufferers struggle to walk, feed and visit the toilet on their own. As the sufferers enter these later stages family members who could once care for them struggle and will have to send them for care somewhere else be it a hospital or care home. However as more people develop these diseases these care homes and hospitals will not be able to cope with the amount of people nor be able to afford to care for all of the patients. This will inevitably lead to either a reduced quality of care due to the number of people, a rise in the cost of care to limit who can afford to put the sufferer into care which will lead to family members dedicating much of their time to caring for the individuals. Perhaps in this dystopian future, euthanasia as seen in parts of central Europe will become legal and more common place in the UK as the country cannot afford to care for all of the sufferers. This will more than likely be the situation the country is faced with and euthanasia will provide an easy solution to a growing problem of an ageing population. Once a person is diagnosed with a fatal illness such as Alzheimer's which advances very quickly over a few years there may only be one solution in a future where there is simply not enough time, space or resources to accommodate those who do not contribute to society.