A librarian for most of her life, she raised three children and was the linchpin of her close-knit family. Their Wangaratta home was full of the smells of her exceptional cooking, and the blooming roses in the garden a testament to her green fingers.

But Wendy, now 63, can no longer read, or write. Stringing words together is a challenge.

Diagnosed with a rare form of early-onset dementia (posterior cortical atrophy) five years ago, she recently moved to an aged-care facility in Yarra Junction, east of Melbourne, when her daily needs became too much for her husband Terry.

As the Australian population ages and we live for longer, the number of people with dementia is predicted to soar. Last year, 237 new cases were diagnosed each day.

And the national cost will more than double in almost 40 years, from more than $14 billion this year to $37 billion by 2056, according to new research on the economic cost of dementia from Alzheimer's Australia.

But the individual costs - financial, social and familial -  are also great, particularly for the families of those whose dementia is diagnosed earlier in life.

When Wendy moved into the home last November, Terry paid a $200,000 bond. He will pay $60,000 per year in out-of-pocket expenses. He also pays for extra carers to spend time with Wendy because she needs different stimulation to her fellow residents, whose average age is over 80.

Terry couldn't sell their home (now in Healesville): he still needs to live in it. They were too young for the pension. So he became his wife's full-time carer and lives on his self-managed super fund. They both had good incomes while they were working.

Terry would like more money spent on research: "A person diagnosed with dementia has no chance. We need the funding to give them a fighting chance, like with cancer".

For people with dementia living in the community, the average total direct costs for the first year after diagnosis is about $45,400. If they are living in a residential aged-care facility this increases to $56,000. These costs include hospitalisations, paid care and doctor visits and vary by age, gender, and disease severity.

Dementia is the second-highest leading cause of death, behind heart disease, in Australia but there is no national strategy to address it, says Alzheimer Australia spokesman Professor Graeme Samuel.

"Dementia is one of the major chronic diseases of this century. The time for action is now. If we don't do something, the cost is going to continue to grow to unsustainable levels," he said.

The Barnett family in the Yarra Junction aged-care facility where Wendy now lives. Photo: Luis Enrique Ascui

Wendy's daughter, Victoria Soffer brings her toddler son Leo to visit his grandmother at the nursing home. He digs about in the garden outside Wendy's unit while she watches. One of his first words was "nana".

Hydrotherapy and music still bring Wendy great pleasure

Her mum's facility is wonderful, says Victoria, but most staff don't have a specialist knowledge of early-onset dementia. And there will be more and more people living in aged care in the same position.

"It quite heartbreaking to think your mum spends her days in a facility where she's the youngest person by a significant margin," Ms Soffer said.

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