21/11/2016 9:05 AM AEDT | Updated 21/11/2016 1:12 PM AEDT

Parkinson's Disease Is A Complicated Illness, And Becoming More And More Common In Australia

It can start with sleep problems and constipation.

Steven Siewert / Fairfax Media
Liz Jackson has Parkinson's disease, and is being supported by partner Martin Butler.

Everyone's journey with Parkinson's Disease is different. Some lose their sense of smell. Some experience slight hand tremors over 20 years while others will degenerate rapidly over two or three years.

There are still big knowledge gaps about this mysterious degenerative disease but Parkinson's Australia chief executive Steve Sant told The Huffington Post Australia was leading world-class research.

Here are the basics of this complicated illness.

Why am I hearing about it?

Australian journalist Liz Jackson is sharing the story of her diagnosis, and it's resonating with Australians, especially those who have a connection to the 70,000 people currently living with Parkinson's.

High-profile campaigners also include actor Michel J Fox, comedian Billy Connolly and the legacy of boxer Muhammad Ali.

Liz Jackson is in her 70s, is that young to be diagnosed?

The average age of diagnosis is 65.

As the Baby Boomers age, will rates of Parkinson's Disease likely increase?

Sant said the answer was yes and Australia needed to prepare.

"What we know is over next 20 years Parkinson's will grow about 4 percent per annum compared to the population growth of 1 percent as people like me are moving into the plus-65 age group," Sant said.

"It's part of the Baby Boomer bulge."

The Victorian Government's Better Health estimated four people per 1000 in Australia have Parkinson's Disease, with the incidence increasing to one in 100 over the age of 60.

What is it exactly?

People with Parkinson's Disease produce less of a brain chemical called dopamine. As well as controlling the brain's reward centres, dopamine is a chemical messenger, allowing signals to be passed from cell to cell.

Without it people can find it hard to control movements and systems may stop working, like sense of smell, bowel movements and mood.

Why is it hard to diagnose?

Sant said there was currently no lab test that could diagnose Parkinson's and instead relied on a clinical picture presented to a doctor.

"There are quite a few conditions that fall into the Parkinson's family like dementia with lewy bodies for example. It means it can take some years to diagnose and some symptoms are very subtle in the early days.

Parkinson's doesn't always start with a hand tremor.

"Someone might have a loss of smell or some constipation -- these early signs of Parkinson's, are fairly non specific. Not everyone presents with a tremor, that classic Parkinson's type thing. I was talking to a guy yesterday who said he got a lot of depression, that was his early symptom."

What causes Parkinson's?

In short, it's not known. It could be genetic in some cases and could be caused by head trauma, toxins or chemicals.

What about research?

A search for a cure continues while research into genetic markers and slowing the progression of the disease make important ground.

Sant said Australians were doing brilliant research particularly at The Florey Institute of Neuroscience and Mental Health, Garvan Institute of Medical Research and at Griffith University in Brisbane.

"We have world-class Parkinson's researchers here and we publish papers at a great rate," he said.

"It can be expensive work, and it needs support from government and the private sector."

What about treatment?

Options available include medication, surgery, and a multidisciplinary response involving physiotherapy, exercise and so on.

"The thing about treatment is that every person with Parkinson's is different. If you got two diabetics in a room together, same age, same gender, chances are they'd have some similarities. But if you have two people with Parkinson's I can guarantee they'll be chalk and cheese.

"That means all care and treatment is individual."

Watch Four Corners' story on A Sense Of Self on ABC TV on Monday, November 21 at 8:30pm.