Dementia: Five priorities

Dementia is described as a "global disaster waiting to happen" and the biggest health and care problem of a generation.

Someone is diagnosed with the disease every four seconds and cases are expected to soar from 44 million now to 135 million by 2050.

The disease already costs the world £370bn ($604bn) each year.

Ministers from the G8 major economies have pledged to tackle this devastating disease.

So what are the priorities?

Diagnose dementia early

Loss of tissue in a demented brain compared with a healthy one

Early diagnosis will be key to tackling dementia.

On the day your doctor tells you that you have dementia you might think that's the early stages of the disease, but it's not.

It takes 10 to 15 years of brain cells dying before memory problems become noticeable and memory tests lead to a diagnosis.

By this stage a fifth of the core memory centres of the brain will be dead.

It's why doctors think drug trials have failed, they're simply trying to treat the disease way too late.

Prof Nick Fox, from the National Hospital for Neurology and Neurosurgery in London, says focusing on earlier treatment is "absolutely critical to research".

Developments have been made. It is now possible to see one of the damaged proteins closely tied to Alzheimer's disease in brain scans, but the challenge is to use these tools to predict the development of dementia.

"There have been huge advances in brain imaging, it's a new era and it is very exciting," said Prof Fox.

Other methods, such as finding chemicals in the blood which might predict the onset of dementia, are being investigated as well.

Dementia is also not one disease, but many. Alzheimer's disease, vascular dementia and dementia with Lewy bodies all have similar symptoms, but may need different treatments. Scientists will need to come up with techniques which can readily distinguish between different forms of dementia.

Stop brain cells dying

There is no drug which can halt or even slow the progression of any form of dementia.

A lot of hope was placed on two potential Alzheimer's drugs - solanezumab and bapineuzumab - but they failed in trials which showed no benefits for cognition.

However, there were hints that solanezumab may work in people with the earliest stages of the disease.

A new trial has started looking at patients with mild dementia.

Dr Eric Karran, director of research at Alzheimer's Research UK, said that if it was shown to work then the drug may be used in a similar way to statins for heart problems.

"I think the pathway now is if solanezumab is shown to work in mild Alzheimer's disease then the pathway would be to give it earlier and earlier and earlier... and you could have confidence you will see an effect."

A cure is obviously the dream, but just slowing the pace of the disease would deliver massive rewards.

Delaying dementia by five years could halve the number of people living with the disease.

Develop drugs to treat the symptoms

Memantine was the last new dementia drug

There are dementia drugs, which help people to live with the condition, but there are not enough.

Medication can boost the chemical signalling between surviving brain cells. But the last new medicine, memantine, was approved by the US in 2003.

Since then there's been nothing.

Dr Ronald Petersen, the director of the Alzheimer's Disease Research Centre at the Mayo Clinic, US, told the BBC: "That's horrific when you think about the billions invested in the disease.

"There are 44 million people with Alzheimer's and we have to treat them as well [as find a cure].

"We need to develop drugs both to treat the symptoms and slow the progression of the disease, as we do after a heart attack."

Find ways to reduce the risk

Want to massively cut the risk of lung cancer? Don't smoke. Want to avoid a heart attack? Then exercise and have a healthy diet.

Don't want dementia? Then the answer is less certain.

Age is the biggest risk factor. In the UK, one in three people over the age of 95 has dementia, but there's not much people can do about that.

Many of the familiar messages - exercise and eat healthily - have been linked to preventing or delaying the onset of dementia.

But the full picture of how family history, lifestyle choices and the environment combine to result in dementia is still unclear.

Prof Peter Passmore, from the British Geriatrics Society and Queen's University Belfast, says the best advice so far is: "To do what's healthy for the heart to reduce blood vessel damage to the brain.

"So avoid obesity, don't smoke, regular exercise, control blood pressure, sugar and cholesterol.

"These are not likely to do harm and may well do good."

Work out the best care

Dementia has huge costs for society, but medical bills account for only a small fraction of the overall bill.

The real cost is in time in care homes and the lost income of families quitting work to care for relatives.

Research will also need to focus on the best ways to care for patients with dementia and to keep them independent for as long as possible.

Studies have already shown that antipsychotic prescriptions can be halved with the correct training for staff.

Dr Doug Brown, from the Alzheimer's Society, said: "If there is any low hanging fruit in dementia it is the care-based research.

"There's a lot we can do about researching the care and support we provide people with now so they can live as well as possible."