Dementia symptoms don’t always include memory loss, particularly in the early stages, at least with some of the rarer types.
Nick Fox, professor of clinical neurology at Queen Square Institute of Neurology, University College, London, and director of the Dementia Research Centre, says there are multiple symptoms of different types of dementia that are not always related to memory, depending on which part of the brain is affected.
“People think of dementia as typically something that affects people when they are really quite old, and that it’s a problem with memory and forgetting,” he says. “Often the image is of it being a relatively benign forgetfulness that is relentlessly progressive.
“That is the typical picture of late-onset Alzheimer’s disease, but we know there are many different forms of dementia, just as there many different types of cancer. Dementia is just an umbrella term – it is very non-specific and doesn’t mean much more than brain failure.
“Symptoms aren’t always memory-related though, and they are not always in people in their 70s and 80s but can occur in people in their 50s and 60s and with some of the inherited types of dementia as early as their 20s, 30s and 40s.”
Some symptoms, such as speech problems, clumsiness and eyesight problems, Prof Frost says, can be a normal part of ageing to some extent, and can have other causes. But a key distinguishing factor for dementia is that the symptoms are progressive, and not normal for you or for someone your age.
To be a genuine cause for concern, it would normally require six months of progressive symptoms for which there is no other explanation (such as an underlying medical condition or the menopause, for instance).
“There would always be no let up from your symptoms – you wouldn’t have a day off from them,” says old-age psychiatrist Dr Chris Fox, a dementia researcher at the University of Exeter. “They would be relentlessly progressive.”
Here are seven early or unusual signs of dementia (and how to distinguish them from normal ageing):
You may notice that you’re having problems judging distances, reading and reaching for objects.
“This is something we often see in clinic,” says Prof Fox. “People will come to us and they may have five or six pairs of glasses, before it’s realised that it’s not a problem in the eyes but in the back of the brain where visual processing takes place.
“This is due to posterior cortical atrophy (PCA), where tissue around the cortex or outer layer of the brain shrinks. It is rare and relatively more common when people are younger, in their 50s and 60s. It’s a variant that affects visual processing before memory. The cause is most often Alzheimer’s.”
“We’re not talking about forgetting names – everyone does that to some extent – but a progressive deterioration in your ability to speak, and often to understand,” says Prof Fox.
“This is known as primary progressive aphasia (PPA) – Terry Jones of Monty Python and, more recently, Bruce Willis have been affected by this. Although speech problems can also be the result of stroke, in PPA the symptoms are progressive.”
Causes include Alzheimer’s disease (AD), but also a rarer type of dementia called frontotemporal dementia (FTD), which affects the frontal and temporal lobes of the brain, leading to problems with speech, language and behaviour. They present in different ways, but the commonality is that people have problems with speaking or understanding that is slowly, relentlessly, progressive.
“It’s not just about not being able to recall someone’s name when you’re tired, or stumbling over finding the occasional word,” says Prof Fox. “It gets worse as the months go by.”
There are different types of PPA. One is a non-fluent variant where people speak in an abnormal and effortful way without fluency, often with pauses between their words. There is also a fluent variant where speech sounds fluent but content is diminished, with words missing and difficulties with naming things that the person used to know.
Hallucinations (seeing things), particularly people or animals that are silent and non-threatening, can be a sign of a condition called Lewy body dementia (LBD), which is caused by abnormal protein deposits in the brain cells.
LBD affects several areas of the brain that control information processing, perception, thought and language, as well as memory. In addition, there are often problems with movement that are seen in Parkinson’s disease.
Symptoms usually start from the age of 65 or older, but sometimes in younger people. There are treatments that have been shown to help symptoms of LBD and AD, but there is currently no cure.
“These hallucinations can be bizarre, but it’s also worth mentioning that you can sometimes get hallucinations if you have an illness such as a urinary tract infection that causes confusion – often referred to as delirium,” says Prof Fox.
“This usually happens relatively quickly and is treatable, whereas LBD would be slowly progressive. It is important to exclude an infection if someone becomes rapidly confused. Sometimes, people are mistakenly believed to have dementia, but actually have delirium due to an infection.”
Bruce Willis’s wife Emma Heming Willis was recently reported to have said that the actor appeared to lose interest in his family in the run-up to his dementia diagnosis.
“Apathy can be a symptom of several types of dementia, including Alzheimer’s, LBD and FTD – it’s when you lose interest in things that have previously been pleasurable and interesting,” explains Dr Ashvini Keshavan, senior clinical research fellow at University College London’s Dementia Research Centre.
“It can sometimes be difficult to distinguish between apathy and depression, and difficult to disentangle the two.
“They might not verbalise feelings of sadness – they might just say, ‘Oh, I don’t fancy doing X, Y or Z’. They may not look sad or depressed, but they may be withdrawing and not seeming to mind and be perfectly happy about it.”
In deciding whether dementia could be the cause, Dr Keshavan says that it’s important to consider what the change is like compared to a person’s existing personality and how their behaviour compares with people of a similar age.
Dr Fox says that these patients may be treated with antidepressants and the medication doesn’t make any difference. “The memory symptoms come later,” he explains. “Apathy and this type of depression are a potential warning sign in middle age and beyond of dementia coming down the line, which is well recognised.
“It could be due to vascular dementia, which is caused by damage to blood vessels supplying the brain with oxygen, or it could be Alzheimer’s.”
“If you’ve always been good at arithmetic and sums but find gradually that you can’t work out figures any more, this can also be a sign of dementia,” says Dr Keshavan.
“The part of the brain that deals with calculations is called the parietal lobe, at the top and back of the brain. So people who have a pathology there, such as posterior cortical atrophy (see above), may notice a problem. They might not have any memory problems.
“If you had the same symptoms overnight, though, it could be a sign of stroke,” he says. “The speed of onset is key.”
PCA can also affect other learned abilities like handwriting, telling left from right or fingers apart.
A University of Birmingham study published in 2022 found that people who had bad dreams in middle age were more likely to have dementia diagnosed in later life. The study followed two groups: middle-aged people between 35 to 64 were followed for nine years, and older people aged 79 and over for five years.
The middle-aged group who had weekly nightmares were four times more likely to experience cognitive decline, and the older group were twice as likely to be diagnosed with dementia.
“This is a really interesting area that we’re still looking into with research,” says Emma Taylor at the charity Alzheimer’s Research UK. “In diseases like Alzheimer’s, we know that changes in the brain can begin 10 to 15 years before symptoms start impacting daily life. Long-term changes in your sleep patterns, including nightmares, may be one of them.
“We don’t know yet, though, whether they are a risk factor for developing dementia or a very early symptom.”
“This is often an early symptom of Alzheimer’s that people can miss, which can happen before any memory problems start,” says Taylor.
“The smell centres in our brain are located very close to the memory centre (the hippocampus), which tends to be where Alzheimer’s disease starts.”
A study by the National Institute on Aging in the US found that a decline in sense of smell was connected to a faster build-up of Alzheimer’s proteins in the brain such as amyloid beta and tau, visible on brain scans.
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