Surrounded by dark shadows, an elderly man sits with his eyes closed and head in one hand.

Just one of many poignant photographs of Dr Edmund Ackell taken by his wife and carer, Judith Fox, it is a powerful attempt to capture the anguish of her husband's battle with Alzheimer's disease.

The once-brilliant mind of the 84-year-old former surgeon and World War II fighter pilot is being slowly destroyed by a disease which affects 700,000 people in the UK.

Diagnosed 12 years ago, just three years after he married Fox, his wife decided to chart his decline through photographs in a bid to "humanise an illness that has been in the closet for too many years".

Her deeply personal images have now been published in the book, I Still Do: Loving and Living with Alzheimer's, which Fox calls a "pictorial tribute" to her husband.

They have also been shown in exhibitions in the UK and the USA.

"Photographing my husband has been an intimate and loving process, as well as a way of keeping him close as he was leaving me," stresses, Fox, aged 68.

The photographer, who lives in California, is no stranger to suffering - her first husband died from cancer at the age of 53.

"I've had experience of Alzheimer's and cancer. They're both horrific diseases, but there's something about Alzheimer's that is uniquely awful.

"That loss of grounding and the loss of your sense of self and the awareness of that loss has got to be one of the most awful things possible."

Ackell is now in the advanced stages of Alzheimer's, but still knows his wife, has moments of lucidity, and can express himself.

However, he has visual agnosia, which means his brain can't interpret what he sees, so he's functionally nearly blind.

He also has severe hallucinations, which have been reduced by medication.

"It's much more of a struggle than it was a year ago, when he had a terrific command of language. That's one of the things he's lost most slowly.

"He still has many lucid moments, moments when we can talk about what he's experiencing."

In the past Ackell has spoken about how frightened he is, and how he doesn't want to be "a burden", explaining in the first years after diagnosis, how he wanted to go into a home when appropriate, but that he'd like to die before he reached that stage.

"I just want him not to feel anxious and fearful," says Fox.

"It must feel horrific to not trust anything around you, to not feel you can put your hands, or mind, on anything."

For the first eight years after her husband's diagnosis, Fox cared for him on her own and didn't take a single day off.

"The thing with Alzheimer's is that you have to be there all the time, and if you're a worrier like I am you're constantly vigilant and you worry that they'll leave a light on the stove, trip over a rug, walk into a window, forget that the stair's there, or get lost," she explains.

"That's aside from all the other things that are going on.

"It's physically demanding, and mentally exhausting."

After eight years she finally hired some much-needed help during the day.

And last July, Fox made the agonising decision to put her husband in a home, or 'facility' as they're known in the USA.

His dementia was too advanced for him to be able to discuss the move with her, but he had, of course, made it clear early on that he wanted to go into a home when he "became a burden".

He'd also repeatedly expressed a desire to 'go home', meaning his childhood home, where he'd been well and felt safe.

"I realised that no matter where he was he would want to go home, and for that and other reasons I knew it was better and okay for him to go into a good facility.

"It was very, very difficult to make the decision. I'd thought about it a year before, but couldn't go there.

"My determination was always to keep him at home, and I did everything possible, including redesigning our home so he could live in it forever.

"Even though intellectually I know him going into the facility is the right decision, emotionally it still tugs."

Since then Fox's book has been published, because, as she explains: "I realised I was in a very unique position to advocate for Alzheimer's awareness through my work.

"It's about life experiences everybody can relate to - there's space in every photograph for the viewer to see themselves or someone they know and love.

"I hope the book will be one more way of people better understanding the disease and the effect it has on the patient and the care-giver."

Fox wants the book to convey "both the pain and the positives", insisting that living with dementia is not all bad.

She illustrates this by describing how, when her husband is depressed, she holds his hand and talks him through it until he smiles.

"To me that's a very good moment," she says.

"I've always focused on what we have, and that's helped me a great deal. You have two choices - you either spend time thinking about all the things you no longer have, or you think about what you still have."

As the disease has not yet got as bad as it could, Fox says she feels fortunate, insisting she can "still see the essence of him in many ways".

"There are gifts that come with this," she stresses. "It's a terrible, horrific disease but there are also good moments and it's not all helpless and hopeless doom and gloom.

"As groundless as Ed feels, he still knows that I am his grounding, I am his rock.

"That's very precious to me."

Her complex emotions will be shared by many of the UK's dementia carers, who do a tough job 24/7.

Two thirds of them still look after their loved ones at home, and are often so busy with their caring role that they're not really visible.

"As a result, we don't have a good enough understanding of exactly what they're doing and the extent to which they're devoting their lives to an individual, and in many cases giving up their own lives," says Andrew Ketteringham, director of external affairs for the Alzheimer's Society.

He says carers often struggle on for much longer than they should, risking their own health.

"And the reason for that is the decision you make to put someone in a care home is hugely difficult, particularly if you've never discussed it with them."

He points out that in the early stages of dementia, patients are able to discuss what they want for the future, as Ackell did with Fox.

"If you've had a discussion with your children or partner about what you want to happen, and say you'll be happy for them to put you into care when necessary, then that's of huge benefit to the person who's making the decision later on."