Imagine the scene: It's Christmas Eve and everything is poised for your guests to arrive. But how do you manage if one of your guests, or somebody you share your home with, is living with a more advanced form of dementia?

[Read more: 11 things you should really know about dementia]

Dementia alters people's perceptions, as Maizie Mears-Owen, Care UK's head of dementia services, explains: "During their training sessions, our teams wear glasses that restrict their vision and have their hearing impaired while people ask them questions - this gives them an idea of how living with dementia affects people."

She says this training provides new perspectives on how we can all help our loved ones enjoy a busy family Christmas.

"Begin to prepare them in advance by talking about who will be there, and who those people are to them - niece, grandson, friend. Photographs are very useful for this as it will help them to recognise faces."

Photographs can also be useful because people with dementia may be living in a different decade. It is common for people to believe they are at a younger point in their lives. If this is the case, use older photos to explain who people are - and don't get upset if your relative gets names wrong.

Muddling might happen

"If your mother calls you 'mum', do not get embarrassed and do not correct her - she is just at the point in her mind where you are her mother's age, or she sees something in you that reminds her of her mum," says Mears-Owen.

"Embrace it. Be 'Mum'. Help her with her food and with opening her presents - she will find it reassuring and calming. Contradicting her will make her feel agitated and confused."

Young children seem to take it all in their stride. However, teenagers can find it upsetting. "Not being recognised or seeing out-of-character behaviour can sometimes be confusing, embarrassing and hurtful," adds Mears-Owen.

She suggests talking the issue over together as a family before Christmas, and also recommends Matthew Snyman's book The Dementia Diaries, which follows four young people dealing with their grandparents' dementias.

[Read more: What it really feels like to suffer from dementia]

Prepare with care

Christmas Eve is the time to start tapping into family traditions. Mears-Owen says: "If you prepare your vegetables on Christmas Eve night, encourage your loved one to take part. They will feel useful and it can start conversations about Christmases past. Reminiscence is vital to increasing wellbeing and something we do across our 114 care homes. Get them talking about their childhood Christmases as well as yours."

Dementia can take a toll on verbal communication skills. "Music is a great way to connect with someone, as well as being fun," says Mears-Owen. "Even if they cannot sing, they can enjoy tapping out a rhythm and joining in, so why not try a carol service or sing along with a CD?"

Make room for calm

Christmas mornings can be frenetic, especially if there are young children in the house. Set aside a quiet and comfortable place for your relative. "The hurly-burly of present opening, noisy toys and over-excited youngsters can prove too much for someone whose senses have changed," Mears-Owen explains.

"To avoid confusion and anxiety, offer your relative a cup of tea away from the chaos and, if they want it, sit with them and chat."

The festive feast

The centrepiece of Christmas is the family lunch. Ann Saunders, a Care UK operational director with a personal interest in nutrition in older people, says: "Dementia can take away depth perception and narrow the field of vision, so keep things fairly clear.

Hand out crackers when you are going to pull them, limit the amount of crockery and cutlery on the table and use a tablecloth that contrasts with the plates. White-on-white blends in and the person will not know where the plate ends and the cloth begins.

"I find a blue or bright yellow plate works best: the meal stands out as there is very little food in those colours. Do not use plates with patterns as these can cause optical illusions and confusion.

"Try not crowding the plate," she adds. "Appetites are small and lots of food adds to confusion. Keep the meat in one section of the plate, the carbs in another and the vegetables separate. It is attractive and clear.

"Taste buds age and older people often develop a sweet, sour or savoury tooth to compensate. Try adding lemon or lime for that extra zing, use plenty of fresh herbs and try adding a teaspoon of honey to the water you cook the carrots in. The most important thing is that everyone indulges in their favourite foodie treats throughout the day."

Finally, just because someone is living with dementia doesn't mean they can't join in the fun and indulgence with the rest of the family.