Of course, as we get older, it is normal to experience an element of memory lapse – so when should you worry? “It will be things that are out of character for that person. With dementia, it is progressive and so can affect daily living.

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“The person that forgets to put the turkey in the oven, or burns the turkey, may be forgetting to put the oven on for dinner every day.”

Repeating questions

“As with memory loss, this is quite consistent across all types of dementia and it can happen quite early,” says Makri. “Someone might ask a question over and over again, and it gets to a point where you realise they’re not retaining this information. It’s quite upsetting to witness.”

Wheeler adds: “The first noticeable sign of Alzheimer’s disease is typically failing episodic memory. This is when a person has trouble encoding new memories of events and is caused by damage to regions of the brain called the hippocampus and the entorhinal cortex.

“It’s declining episodic memory that causes the ‘saying the same thing, over and over’ symptom because the person doesn’t recall having said it previously. They never stored the memory in the first place so it doesn’t inform their future thoughts and actions.”

Difficulty carrying out familiar daily tasks

While a complex matter like making a whole Christmas dinner would be enough to confuse a lot of us, there may be a problem if someone has difficulty carrying out one familiar job.

“For example, if the same person always does the stuffing every year and then they forget to bring the ingredients, or they forget the process of how to do it. People will begin to have difficulty remembering the process of something, or planning, or concentrating.”

Difficulty with tech

“Confusion with technology is not, of course, specific to people living with dementia,” says Wheeler. “However, people with dementia can – and do – struggle with technology.

“As their condition deteriorates over time, their brain will increasingly struggle to process information and think clearly, meaning that technologies that were once easy to use and navigate, for example a mobile phone or a laptop, may become increasingly difficult to use.”

Difficulty following a conversation

“People can have difficulty finding the right word, or just following the thread of a conversation.” says Makri. “They might take longer to process the information they’ve heard, or they might just not be communicating very much. Sometimes they will become a bit withdrawn. They retreat slightly because, actually, they can’t follow the thread of the conversation any more.”

Wheeler adds that although people with vascular dementia may not have problems with memory at first, in the context of a conversation they may easily lose the thread, either because they get distracted, they get overwhelmed by too much information, or because their working memory – the ability to keep a thought in your head for a few seconds or more – isn’t working as well as it used to.

Spatial and temporal awareness

This can be a symptom of all types of dementia. “Sometimes people might be confused about the time or the place,” says Makri. “They might not realise whose house they’re in, or not remember where the loo is. They might know it’s Christmas because they’re sitting at a Christmas table with a turkey in front of them, but they might not remember what year it is.”

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Difficulty controlling emotions

The key is whether their behaviour is out of character. “If this is someone who’s always got really angry or anxious about politics, then you might not worry. But if this is someone who doesn’t normally react this way at that point, if they’re suddenly having mood swings and having difficulty controlling their emotions, then this might be an early sign [of some forms of dementia].”

People with vascular dementia, in particular tend, to be more prone to mood problems as well as fatigue, and difficulty concentrating.

Inappropriate behaviour

This is more of a problem with frontotemporal dementia, a less common type of dementia that involves degeneration in the frontal or temporal lobes of the brain.

Early symptoms include changes in personality and behaviour, and/or language difficulties. “You may find a person becomes less inhibited; they might suddenly start saying or doing inappropriate things,” says Makri.

Being suddenly suspicious

Although this isn’t present with Alzheimer’s, vascular or many other types of dementia, Lewy body dementia – a broad term which includes “dementia with Lewy bodies” and Parkinson’s dementia – can cause delusional beliefs or hallucinations.

“Having incorrect beliefs could potentially be an early symptom,” Makri explains. “At that point, it’s generally quite mild, but certainly saying something like ‘the neighbours keep having a go at me’, or having a suspicion that the neighbours are talking about them” could be a sign that something is amiss.

What should you do next?

Firstly, how much should you worry? “Many of the early symptoms can be caused by other things,” says Makri.

“We always say you can’t make a diagnosis at the dinner table. But if someone is presenting with a lot of these symptoms, it is a good idea for them to speak to the GP.”

The GP will generally carry out tests to rule out other causes, including thyroid deficiencies, urinary tract infection (UTIs) and vitamin B12 deficiency, which can all cause confusion.

But how to broach the topic sensitively? Makri suggests, after speaking to other people who were present, to nominate one close family member to bring this up with the person in question. It’s also helpful to keep notes of the symptoms.

Ideally, the person themselves will go to the GP, who may then follow up with a referral to a memory clinic and possibly a brain scan. If the person is in denial – which can itself be a part of dementia – a family member can ring the GP and pass on their concerns, and while the GP won’t be able to comment because of patient confidentiality, they may be able to follow up with the patient.

The Telegraph, London