Media playback is unsupported on your device Media caption Christopher struggles to remember Veronica's name

Three years ago, the Victoria Derbyshire programme asked three people with dementia to document their lives for a month. What has changed since?

Christopher's story

Christopher Devas was diagnosed with Alzheimer's disease in 2008.

When we first met him and his wife Veronica three years ago, he had difficulty remembering certain words, but was able to speak in full sentences and convey his emotions verbally.

Now, the condition means he cannot remember his wife's name.

"This is one of the things that is particularly sad," says Veronica as she records herself asking her husband what she is called, to no avail. "I don't have a name."

When first asked Christopher simply murmurs the word "oh", as he struggles to think.

"I can't remember," he then replies.

Image copyright Mr and Mrs Devas Image caption Christopher used to build boats, and loved going on sailing holidays

"Everything's changed," explains Veronica, speaking directly to her husband. "It's sad, very sad, but you mustn't dwell on that because otherwise you'd be like that all the time.

"And I mustn't be sad for you, because you're positive."

Veronica says she leads a full life, taking Christopher to meet friends, to choir practice and for long walks along the Dorset coast. He still tells her he feels happy.

But at times she feels isolated - unable to communicate with her husband as she once did.

"It's lonely, yes, it is quite lonely," she says. "But then he doesn't realise that, so it's not as though you're living with somebody who is doing something to make you feel like that."

Christopher - a former magistrate - has now been given a disabled parking badge, which Veronica says makes life a lot less stressful.

But the invisible nature of Alzheimer's can cause problems.

Recently the couple were stopped getting into their car by someone who told them they did not look "ill enough" for the blue badge.

"'You're not disabled', this man said, as we were parked. So I said to him, 'You change spaces with me for 24 hours'."

Christopher's memory and speech may have declined, but Veronica says his "interaction and feeling hasn't gone... even though he may not be able to put it into words".

He claps as he sees himself on television from his first appearance on the Victoria Derbyshire programme.

He smiles affectionately as Veronica tells him: "I love you".

Wendy's story

"I used to love York. I thought it was my forever home," explains Wendy Mitchell, who was diagnosed with early onset Alzheimer's in 2013, aged just 57.

"But it became a very confusing place and I needed more silence - so that's why I moved to the village I'm in now."

Over the last three years, Wendy's dementia has meant she has had to give up work and move home to live near one of her daughters.

Her new house has a picture of a forget-me-not either side of the door, so Wendy can recognise it.

"When I first moved all the houses looked the same, and I got confused as to which one I lived at. I would constantly walk up my neighbour's path," she explains.

Media playback is unsupported on your device Media caption Wendy keeps a picture of a forget-me-not by the door so she can remember her home

Getting used to the inside of the new house also became a challenge.

"The kitchen used to have two doors [exiting from it], and I could never remember where each door led. I'd end up going round and round in circles," she says.

By 2050, 1.3 million people will be living at home with dementia in the UK, according to new research from the Alzheimer's Society.

The figure currently stands at just over half a million.

Wendy enjoys living by herself and is keen to retain her independence, but she has also had to adapt other parts of her life to the condition.

Media playback is unsupported on your device Media caption In her video diary three years ago, Wendy relived the moment of her first significant memory loss

She now speaks more slowly than she used to, taking longer to remember words and what it is she wants to say.

"I stopped answering the phone because when I do people can't see me," she explains.

"They can't see me thinking, which means they then interrupt me and I just get totally confused."

Wendy prefers email or text. She can type words more quickly than she can speak and even had her memoirs published earlier this year.

She questions why so many services - like hospitals - require patients to call in order to discuss treatment or change appointments.

Image copyright Wendy Mitchell Image caption Wendy with her daughter

But Wendy says life with the condition "can still be filled with laughter and adventures and almost a new way of living".

She thinks too often it is the very final stages of dementia that are shown in the media.

In May 2017, she took her first flight in a glider plane, bought for her by her daughter as a birthday present.

"It was the most amazing experience, because I have no fear any more," she says.

"I always think that I faced my biggest fear by facing dementia."

Keith's story

"I still am positive, I am still a driven person I would say," former head teacher Keith Oliver explains looking back over the last three years.

"But I'm less confident now than I was then. I am more fragile. I have a thinner skin."

Keith was diagnosed with Alzheimer's in 2010.

"Some days are foggy," he explains. "The fog comes down and then the fog lifts. It's patchy. And that's what dementia is often like.

"Even today I'm experiencing that. Some of my clarity of thinking is coming and going," he adds, before pausing.

"I've lost my train of thought Jim," he tells me. "You're going to have to ask me your question again."

Image caption Keith says books have become an increasingly important part of his life

Since being diagnosed Keith says he has experienced depression for the first time.

He thinks it exacerbates his dementia, making him feel isolated, lonely and frustrated.

But he is keen to enjoy life and give himself time to think, often going on walks along the Channel coast in Kent.

Watching the boats sway from side to side in the water, he says, reminds him "of how some days it is for me, when walking or standing and trying to keep my balance".

Image copyright Keith Oliver Image caption Keith was a primary school teacher for more than 30 years

As a former teacher, books have always held an important place in his life.

"Here's one I read a couple of years ago, about something very close to my heart - Nottingham Forest," he says, taking it from his overflowing bookcase. "Reading the books bring back those memories of happy days."

He still reads a lot but says it is becoming more difficult, as he remembers "very little".

"There are times now where I go into the bookshop, and sometimes I've brought the book home and realised I've read it before."

Asked if he will remember our conversation, he replies: "I'll remember how this conversation made me feel. But the actual subject matter that we talked about, no I won't."

Watch the BBC's Victoria Derbyshire programme on weekdays between 09:00 and 11:00 on BBC Two and the BBC News Channel.