Parkinson’s disease is a condition in which parts of the brain become progressively damaged over many years.
Around one in 500 people are affected by Parkinson’s disease, according to the NHS, meaning there are an estimated 127,000 people in the UK with the condition.
There is no cure for the disease, which makes it increasingly difficult for sufferers to carry out everyday activities without assistance.
However, symptoms can be improved with the right treatment, meaning most people with the disease now have a normal or near-normal life expectancy.
The symptoms usually develop gradually and are mild at first.
The three main symptoms affect physical movement. These include:
Tremors
Tremors refer to the involuntary shaking of particular parts of the body. They usually begin in the hand or arm, and are more likely to occur when the limb is relaxed and resting.
Slowness of movement
Otherwise known as bradykinesia, this refers to physical movements that are much slower than normal.
This can make everyday tasks difficult and can result in a distinctive slow, shuffling walk with very small steps.
Muscle stiffness
Stiffness and tension in the muscles can make it difficult to move around and make facial expressions, and can result in painful muscle cramps.
“The order in which these develop and their severity is different for each individual,” said the NHS.
“It’s unlikely that a person with Parkinson’s disease would experience all or most of these.”
“These main symptoms are sometimes referred to by doctors as parkinsonism as there can be causes other than Parkinson’s disease.”
Parkinson’s disease can also cause of range of other physical and mental symptoms.
These can include problems with balance, loss of sense of smell, nerve pain, urinary incontinence, and constipation.
Other symptoms include erectile dysfunction in men, sexual dysfunction in women, dizziness, blurred vision or fainting, excessive sweating and swallowing difficulties.
Excessive production of saliva, insomnia, depression or anxiety, memory problems and dementia are also potential symptoms.