What is Parkinson's disease?

Parkinson's disease is a condition in which parts of the brain become progressively damaged over many years, according to the NHS website.

What are the symptoms?

The NHS says there are three major symptoms, including tremors or shaking, slowness of movement and muscle stiffness.

Other symptoms include problems with balance, loss of smell, nerve pain, excessive sweating and dizziness.

Some people can also experience lack of sleep, excessive production of saliva and problems swallowing, causing malnutrition and dehydration.

What are the early signs?

Symptoms can start gradually, sometimes beginning with a barely noticeable tremor in just one part of the body.

In the early stages, people may show little or no expression, and their arms may not swing when they walk.

Speech can also become soft or slurred, with the condition worsening over time.

What are the causes?

Some scientists believe a combination of genetic and environmental factors are the cause of Parkinson's disease.

It occurs after a person experiences loss of nerve cells in a part of their brain.

However, it is not known why the loss of nerve cells associated with the condition takes place but research is ongoing to identify potential causes.

Scientists say genetics factor can increase a person's risk of developing the disease, and can therefore run in families.

Other factors attributed to causing the condition include environmental problems such as pollution, though such links are inconclusive, the NHS says.

How is it diagnosed?

No tests can conclusively show if a person has the disease, but doctors can make a diagnosis based on symptoms, medical history and a physical examination.

A specialist will ask the person to write or draw, walk or speak to check for any common signs of the condition.

They may even check for difficulty making facial expressions and slowness of limb movement.

How many people are affected?

Around 145,000 people live with Parkinson's disease in the UK, according to the charity Parkinson's UK.

What happens if someone is diagnosed?

According to the charity, it is a legal requirement to contact the DVLA, as a diagnosed person will need to have a medical or driving assessment.

The organisation also advises people to contact any insurance providers and find out about financial support available.

People are also encouraged to partake in more exercise.

Can it be treated?

Although there is no cure, a number of treatments are available to help reduce the symptoms.

The main remedies include medication, exercise, therapy and surgery, which can help people in different ways.

What medication is available and what are the side effects?

Medication can be helpful in improving the main symptoms of Parkinson's disease, such as shaking and movement problems.

There are three main types which are commonly used, levodopa, dopamine agonist or a MAO-B inhibitor. Each can affect people in different ways.

The drugs do have some side effects, including impulsive and compulsive behaviour, hallucinations, sleep issues and blood pressure changes.

What therapy is available?

There are several therapies available to those with Parkinson's through the NHS.

Among them are physiotherapy to reduce muscle stiffness, occupational therapy to help with completing day-to-day tasks and speech and language coaching.

Does this change the way you live?

Most people's life expectancy will not change a great deal, though more advanced symptoms can lead to increased disability and poor health.

It can also cause some cognitive issues and changes to mood and mental health.

Those with Parkinson's are encouraged to exercise more often, with scientists saying 2.5 hours of exercise a week is enough to slow the progression of symptoms.