Forgetfulness isn’t the first warning sign. Scientists have identified six non-obvious symptoms that can appear 15–20 years before cognitive decline begins. And the good news? Nearly half of all cases can be prevented.
When we hear the word “dementia,” images of memory loss and confused elderly people immediately come to mind. But the reality is more complex. Modern science tells us that Alzheimer’s disease doesn’t start with forgotten keys or names. Its first “whispers” are changes in mood, gait, smell, and sleep — and they emerge long before doctors even suspect anything is wrong.
According to The Washington Post, as reported by ForumDaily, biological changes in the brain begin 15 to 20 years before obvious cognitive problems appear. And if we learn to recognize them, we gain precious time to slow down or even prevent the disease from developing.
“A person can have many of these precursors and yet show no cognitive symptoms at all,” explains Timothy Chang, assistant professor of neurology at the University of California, Los Angeles.
Research shows that about 45% of dementia cases can be prevented through lifestyle changes. This isn’t hypnosis or miracle pills. It’s physical activity, healthy eating, brain training, social connections, and quality sleep.
Here are six early markers worth paying attention to.
1. Depression and Anxiety After Age 55
Don’t dismiss sudden sadness or anxiety at age 55–60 as a midlife crisis or simple fatigue. This could be a signal of neural changes.
A study of more than 1.4 million Danes found that people with depression had a 2.4 times higher risk of dementia. Moreover, depressive and anxiety disorders don’t just precede the disease — they can also accelerate its progression.
“Changes in the brain’s neural networks during the early stages of dementia also affect mental state,” Chang explains.
2. Mood Swings: From Apathy to Outbursts of Anger
If you or your loved ones have noticed that someone has become irritable, short-tempered, or conversely, indifferent to everything — this isn’t “character deterioration.” It’s a possible neuropsychiatric symptom.
In a 2017 study, neuropsychiatric symptoms were observed in 31% of healthy older adults, 47% of those at higher dementia risk, and 54% of those with existing cognitive impairment.
“If you constantly lash out at those around you and your relationships become a series of conflicts, see a geriatric psychiatrist,” advises Adam Turnbull from Stanford.
3. Sleep: When Rest Doesn’t Restore
Sleep is when the brain does its “deep cleaning,” flushing out toxins including beta-amyloid. If this process is disrupted, the risk of harmful protein buildup increases.
What should raise concern:
- insomnia or frequent nighttime awakenings;
- excessive daytime sleepiness;
- restless legs syndrome;
- sleep apnea.
A 2025 meta-analysis covering 39 studies confirmed the link between these sleep disturbances and increased dementia risk. Interestingly, each additional hour of nighttime sleep was associated with lower beta-amyloid levels in the brain.
4. Your Nose Stops “Hearing” Smells
Loss of smell is one of the earliest and most underestimated warning signs. About 85% of people in the early stages of Alzheimer’s experience problems distinguishing scents.
Why does this happen? The olfactory system has a direct connection to the hippocampus and amygdala — areas responsible for memory and emotion. Smell signals reach the brain faster than visual or auditory ones.
The good news: your sense of smell can be trained. And there’s evidence that such training improves cognitive function even in those whose sense of smell is still intact.
5. Your Gait Slows Down
We’re used to thinking that slowing down is just part of growing old. But a 2024 study of more than 1,300 people over 65 found that gait deterioration (speed, ability to turn around) begins 10 years before cognitive decline.
This isn’t just muscle weakness. It’s a signal that the brain — which controls coordination — has already started to change.
6. Your Handshake Gets Weaker
Grip strength is one of the most accurate markers of biological age. A study of nearly 200,000 adults found that every 5-kilogram decrease in grip strength increases dementia risk by 20% in men and 12% in women.
Weaker grip correlates with poorer performance on memory and problem-solving tests. This symptom can appear about a decade before cognitive impairment sets in.
What to Do If You Notice These Signs?
First don’t panic. Many of these symptoms can be caused by a dozen other factors, from stress to vitamin deficiencies.
Second don’t ignore them. If you or your loved ones notice at least two or three symptoms from this list, and they’re accompanied by concerns about memory, see a doctor.
Today, medicine has tools for early diagnosis:
- PET scans;
- cerebrospinal fluid analysis;
- new blood tests for biomarkers.
“It’s helpful to get checked out and have a doctor assess whether there’s really cause for concern or not,” emphasizes Timothy Chang.
Early diagnosis gives more time for intervention and increases the chances of maintaining quality of life.
How to Reduce Your Risk: 5 Simple Steps
The POINTER study conducted in the U.S. showed that a comprehensive approach works best. Here’s what you can do starting today:
- Move your body. Physical activity improves blood flow to the brain.
- Eat well. The Mediterranean diet is considered one of the best for brain health.
- Train your brain. Solve puzzles, learn new things, stay social.
- Sleep 7–8 hours. Quality sleep is the brain’s main “cleaner.”
- Limit alcohol and protect your hearing. These factors also influence dementia risk.
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Dementia is not a death sentence. And we have time and tools to prepare, to notice, and to act. Paying attention to yourself and your loved ones is the first and most important step.
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