The son of a dementia victim has described the crippling effects of the disease, on the same day David Cameron announced a doubling in UK funding for research into the illness.
Pauline Murray-White's son has filmed his mother's battle with the illness since she was diagnosed in 2007, capturing the moment she struggled to recognise a photograph of her late partner.
James Murray-White said his mother's personality has gradually disintegrated: "Dementia just strips someone of their character, their personality, who they and what they knew."
Mr Murray-White said the relationships of sufferers "eventually shatter."
The World Health Organisation predict that numbers of dementia sufferers will almost double worldwide every two decades.
David Cameron told the G8 summit into dementia that the goal of finding a treatment to cure or halt dementia by 2025 is "within our grasp".
The Prime Minister said the world should be "just as resolute" in tackling dementia as it had been in the past in seeking treatments and cures for diseases like malaria, cancer and HIV/Aids.
Mr Cameron said he wanted the Government investment in dementia research to double from £66 million in 2015 to £122 million in 2025.
Health Secretary Jeremy Hunt said the G8 had agreed to work together to find a cure or disease-modifying therapy "to stop dementia in its tracks".
A dementia envoy is also being set up to look into attracting other sources of funding for dementia research, including from private companies.
In the NHS, the aim is to ensure that diagnosis rates rise from below half to more than two-thirds.
Charities welcomed the boost to funding, claiming it was a sign the UK was demonstrating global leadership on the issue.
Jeremy Hughes, chief executive of the Alzheimer's Society, said: "Today the UK has demonstrated global leadership on tackling dementia.
"We have committed to a global plan, better support for people with dementia through research and the Prime Minister has agreed to narrow the funding gap between dementia and cancer research - something we have long campaigned for.
"Dementia has come out of the shadows and is centre stage - but we must ensure G8 has a lasting legacy."