Cryptocurrency is the hottest financial product in the world.  

The hype is everywhere, with forms of the digital currency endorsed and advertised by celebrities daring you to invest in this brave new world.  

Not everyone is convinced by the glossy ads and bold claims.

Four Corners investigates what lies behind the slick marketing and big promises to examine if it's a fad, a fraud or the future.

Dr Norman Swan reports on "Holding on to Hope", looking at lifestyle choices whch may help delay the onset of dementia.

"It's the number one fear that older people have. More than any other disease … more than anything else." (Dementia clinician)

Half a million Australians live with dementia and for the past two decades scientists have been working on a new drug treatment they hope will combat the most common form, Alzheimer's disease.

"If we can give people another five years of quality life, that's going to make a massive difference to people around the world. It's going to make a massive difference to healthcare systems around the world as well." (Neurologist)

ABC's health expert Dr Norman Swan investigates the science behind the treatment in the race to solve dementia.