Cognitive decline rarely announces itself loudly. Unlike a sore back or aching joints, changes in brain health often arrive quietly, gradually altering everyday abilities until one day you realise you are not as mentally sharp as you once were. According to Professor Ben Parris, a leading expert in cognition and cognitive neuroscience, recognising these early changes is critical to preserving long-term brain health.
Parris, who teaches at Bournemouth University’s School of Psychology and co-founded its Interdisciplinary Neuroscience Research Centre, says that many people underestimate how subtly the brain ages.
“A decline in cognitive health can creep up on you,” he explains. “You may suddenly notice it’s harder to hold conversations, remember numbers, or complete routine tasks that once required no effort at all.”
These changes are often linked to the gradual shrinkage of the frontal lobe, the region of the brain located just behind the forehead. The frontal lobe governs executive functions such as planning, focus, organisation, and decision-making. While some degree of deterioration is a normal part of ageing, the speed and severity vary widely from person to person.
“This is not the same as dementia,” Parris emphasises. “But diseases like dementia accelerate the same processes that naturally occur with age.”
Importantly, Parris says he has observed many individuals in their 60s, 70s, and beyond whose frontal lobes remain highly functional. The key difference lies in awareness and early intervention.
“The earlier you notice changes, the more you can do to slow them down,” he says.
1. Struggling to Multitask
One of the earliest warning signs of cognitive decline is difficulty switching between tasks. This might show up while cooking a meal and attempting to hold a conversation at the same time.
“You might find yourself unable to respond to someone because your mind is still focused on the next step in a recipe,” Parris explains. “Tasks begin to blur together, and the sharpness you once had feels dulled.”
This reflects a decline in cognitive flexibility—the brain’s ability to shift attention between tasks. Because multitasking is one of the most demanding mental activities, it is often the first ability to weaken.
“In extreme cases, people continue an action even after it no longer makes sense,” Parris notes. “I’ve seen individuals stirring a pot without the spoon still in their hand.”
2. Skipping Words While Speaking
Occasionally jumbling words is normal, especially when tired. However, regularly skipping words in sentences may signal deeper issues.
“If you mean to say, ‘I’m just going to pop to the shops,’ but instead say, ‘I’m just shops,’ that’s something to pay attention to,” Parris says.
This can indicate a breakdown in response inhibition, a frontal-lobe function that helps suppress irrelevant information until the right moment. When this mechanism weakens, language becomes fragmented and less precise.
“This kind of language breakdown can be an early marker of dementia,” he warns.
3. Mixing Up Related Words
Another sign of declining cognition is frequently substituting words with related—but incorrect—alternatives.
“When you want to say ‘fork,’ related words like ‘knife’ or ‘spoon’ may intrude,” Parris explains. “As the condition worsens, substitutions become more distant, such as saying ‘plate’ or even ‘train’ instead.”
The frequency and severity of these substitutions can offer clues about how much cognitive decline has occurred, as they suggest misfiring in neural pathways responsible for language and inhibition.
4. Forgetting Essentials Like Your Wallet
Everyday planning relies on working memory—the ability to hold and manipulate information. Forgetting to bring a wallet to the supermarket can be an early sign that this system is faltering.
“Your brain usually runs through a checklist automatically: where you’re going, how you’ll get there, and how you’ll pay,” Parris says. “If one of those elements drops out, it signals a working memory failure.”
Occasional lapses are normal, he notes. “I’ve driven to the supermarket and walked home, forgetting I took the car because I was deep in thought.”
However, increasing frequency of such errors may warrant medical attention.
5. Wandering the Shop Aisles Repeatedly
Difficulty remembering what you need to buy or repeatedly walking down the same aisles is another warning sign. This reflects problems with short-term memory and spatial awareness.
“In studies, people with cognitive decline follow illogical paths through shops,” Parris explains. “They repeatedly visit the same areas because they forget where they’ve already been.”
Such behaviour may feel harmless at first but can indicate deeper neurological changes.
When to See a Doctor
Parris recommends seeing a GP if these symptoms worsen or interfere with daily life. He also stresses listening to loved ones.
“Sometimes people are unaware of their own decline, a condition known as anosognosia,” he says. “If someone close to you is concerned, that alone is reason to seek advice.”
Early assessment can rule out causes such as stroke or tumours and may involve memory tests and brain imaging.
How to Protect Your Cognitive Health
“There are no miracle cures,” Parris says. “Brain health follows the same rules as physical health.”
A balanced diet rich in leafy greens, fish, nuts, and berries supports cognitive function, while both cardio and strength training help maintain brain volume. He also advises limiting alcohol and avoiding smoking.
“Alcohol has been linked to brain shrinkage and poorer memory performance,” he says. “If you drink, do so socially and sparingly.”
