It is estimated that one-in-three people over 65 will die with dementia.
Researchers say there is a lack of evidence on how to provide the best care for patients with advanced dementia who are terminally ill.
This week a group of leading health charities wrote to the prime minister urging him to make this a priority as part of his "dementia challenge".
I have been to see a new approach to looking after people with severe dementia that's on trial in several care homes in south London.
The programme is called Namaste, in this case meaning "to honour the spirit within".
It has been developed for care home residents with severe dementia who can no longer speak up for themselves. They may be immobile, and prone to infections. They often have difficulty swallowing, and may suffer from pain.
At many homes they may be confined to their rooms or placed for hours in front of the TV. At Park Avenue care home in Bromley in Kent staff introduced the Namaste programme last summer.
Sooth the senses
This approach - developed in the United States - soothes the senses, using sound, touch, smell and taste. These are all familiar techniques, but here they are brought together every day in a dedicated communal space.
The residents with advanced dementia are gathered in a Namaste room, where they are greeted and groomed, massaged and stroked. Staff offer sweet treats to help keep their mouths moist, or discuss favourite old photos, against a gentle soundtrack of birdsong from a CD.
Glenis Aylott, whose father Joe Oatley died here a few weeks ago, says his final days were peaceful and dignified.
"It was just the general ambience of the room and the quietness. It just made me feel calm, and he did seem very calm."
Jasrin Azeem, a nurse and team leader at the home, says since Namaste started last year, care has become more purposeful.
"We have one hundred per cent satisfaction doing Namaste. We have time to sit with the residents and talk to them and understand them. "
Central to this approach is a recognition that residents with severe dementia are terminally ill, and so the priority is to provide peace and comfort through palliative care.
Dr Liz Sampson from the Marie Curie Palliative Research Unit says in many care homes and hospitals this can be a difficult step.
"I think people who work in medical and social care are finding it very difficult to recognise that point at which you change the goals of care. And often that step comes too late, and unfortunately people may then die in an acute hospital or an A and E department on a trolley."
Dr Sampson puts this down to a lack of understanding about advanced dementia.
"We were very disappointed that there was no mention of end-of-life care or advanced dementia and the care needs of people with advanced dementia in the prime minister's recent challenge on dementia. I think that was an opportunity that was missed."
This week several leading charities, including Sue Ryder, Dementia UK, and The National Council for Palliative Care (NCPC), wrote to the prime minister. They praised his commitment to improving dementia care, but warned that end-of-life care must not be overlooked by the teams set up to implement his plans.
"The Champion groups that you have established must ensure that your challenge leaves no part of dementia care untouched, and end-of-life care must be seen as an integral part of that mission."
In response the Department of Health in England said: "We can assure the NCPC that improving end-of-life care for people with dementia is very much a priority for government and it is an important objective in the National Dementia Strategy. That is why the NCPC will be an important member of one of the prime ministers' three Champion groups on dementia."
Researchers hope a trial of the Namaste programme at six care homes in south London will provide valuable insights into advanced dementia care, and its potential for much wider use. The study is being led by Jo Hockley, a consultant nurse from St Christopher's Hospice.
"Although anecdotal at the moment we are seeing staff engage better as a team, working together as a team. And if they feel feel more valued and working better then they'll give better care to the residents and the families. So I think the potential is enormous."