Parkinson's disease is a chronic, progressive and incurable disease of the central nervous system, making it one of the most common neurological conditions, second only to dementia. It affects walking, talking, writing and swallowing, and is characterised by involuntary movements, such as shaking, rigidity and difficulty walking. It can also include non-motor symptoms such as pain, sensory changes, gastrointestinal system changes, depression and problems with memory, thought and sleep. The condition is linked to an imbalance between two brain chemicals, or neurotransmitters: dopamine and acetylcholine. The destruction of cells in a tiny region of the brain called the substantia nigra leads to a lack of dopamine, which is important in the control of movement.
Parkinson’s disease is the second most common neurodegenerative disease after dementia, affecting more than ten million people worldwide. While Parkinson’s primarily affects adults over the age of 55, 20% of those diagnosed with the condition are under 50 and 10% of cases occur in those under 40.
An Australian study in 2011 estimated that about one in 350 Australians had Parkinson's disease. By 2018, it was closer to one in 300, or approximately 80,000 people; among those over 70 years of age, 1 in 1,000 are afflicted. The estimated costs of Parkinson’s disease to the Australian economy add up to almost A$1.1 billion, a number that has almost doubled since 2005. The prevalence of the disease is estimated to double by 2030.
In the UK in 1994 it was estimated that the disease cost more than £3 billion a year for the 112,000 sufferers (namely £30,000 per year each).