Explainer: What is Alzheimer’s disease?

25th December 2017 By Sharon Darwish

Alzheimer’s disease is a progressive neurological disorder that slowly destroys memory, cognitive ability and eventually the ability to carry out simple tasks.

The disease is named after Dr Alois Alzheimer, who first described the condition in 1906 after detecting unusual differences in the brain tissue of a patient who had died of a rare mental illness. The patient’s symptoms including memory loss, language difficulties and unpredictable behaviour.

On post-mortem examination, Dr Alzheimer examined his patient’s brain and found abnormal clumps (known as amyloid plaques) and tangled bundles of fibres (known as neurofibrillary, or tau, tangles). These plaques and tangles are now synonymous with Alzheimer’s disease.

alzheimer's disease vs healthy brain

Another feature of Alzheimer’s disease is the damage of connections between nerve cells in the brain. This disrupts the transmission of vital messages between different parts of the brain, as well as signals from the brain to muscles and organs around the body.

The damage appears to start in the hippocampus, the brain structure primarily responsible for memory formation. As more neurons die, more structures are affected and more symptoms develop, increasing in severity. By the final stage of the condition, damage is widespread, and brain tissue has shrunk significantly.

In line with the progressive brain damage of Alzheimer’s disease, symptoms of the condition are typically mild to start with, but worsen over time and interfere with a person’s everyday activities.

Although Alzheimer’s symptoms vary, some are more common than others. For the majority of Alzheimer’s patients, the initial symptoms are memory lapses. Patients may experience difficulties recalling short-term memory and learning new information,  although episodic memory – memories for significant historic life events –  typically stay intact during the early stages of the disease.

As the condition progresses, memory loss worsens. An Alzheimer’s patient may:

People affected by the disease typically develop problems with other aspects of thinking, reasoning, perception or communication too, including:

Those in early stage Alzheimer’s also often experience anxiousness, irritability or feel depressed. Many withdraw from their daily activities and lose interest in their hobbies. With disease progression, some become increasingly worried, angry, or violent, while problems with memory loss, communication, reasoning and orientation become more severe.  When this happens, patients need increasing amounts of daily support from those who care for them.

Some people start experience delusions or hallucinations and can develop behaviours that seem out of character. These include agitation, calling out, repeating the same question, disturbed sleep patterns or reacting aggressively. This is often distressing and challenging for both the patient and their carer.

In the later stages of Alzheimer’s disease, some become much less aware of their surroundings. They may have difficulties eating or walking without help and become increasingly frail. Sadly, in time, many need help with all their daily activities.

How quickly does Alzheimer’s progress and how long do people live?

The rate of Alzheimer’s progression and patients’ life expectancy can vary a great deal. People affected by Alzheimer’s disease may live for eight to ten years on average after the initial symptoms surface. However, this can vary greatly, depending on the age of onset.

Who does Alzheimer’s affect?

Alzheimer’s disease is most common in people over the age of 65, although a small percentage of people under this age also develop it (early-onset Alzheimer’s). Over the age of 65, a the risk of developing Alzheimer’s disease doubles approximately every five years.

Is Alzheimer’s disease preventable?

While age is the biggest risk factor for most cases of Alzheimer’s, there are a number of lifestyle and general health factors that could increase or decrease a person’s chances of developing the disease. One in three cases of Alzheimer’s is preventable and linked to changeable lifestyle factors, according to a team of researchers from  Cambridge University.

The team analysed population data to work out the main seven risk factors for Alzheimer’s disease, which they found to be:

  1. Diabetes
  2. Mid-life hypertension
  3. Mid-life obesity
  4. Physical inactivity
  5. Depression
  6. Smoking
  7. Low educational attainment

The researchers calculated that by merely reducing each of these factors by 10%, almost nine million cases of Alzheimer’s disease could be prevented by 2050.

The research also highlighted the power that physical activity can have to positively transform our lives. Out of the seven factors, the largest proportion of cases of Alzheimer’s in the US and Europe was attributed to physical inactivity. Exercise could prevent many people from developing dementia, by decreasing obesity levels as well as hypertension and diabetes, .

Staying mentally active

is alzheimer's preventable?Keeping yourself mentally, physically and socially active can help you stay healthy as you age and reduce chances of cognitive decline and developing Alzheimer’s disease.

People can reduce their risk of Alzheimer’s disease by leading an active lifestyle. Activities such as:

Alzheimer’s support

Alzheimer’s disease can intensely affect a person’s life as well as their family and carers. If you are affected by Alzheimer’s disease, you may have many questions and concerns. Practical and emotional support can make a tangible difference here.

Many organisations offer information, support and care services to those impacted by Alzheimer’s disease. This can include home, day and respite care. Some helpful organisations in the UK include:

Next: Learn how lifestyle medicine is reversing long term diseases.

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