Dementia affects millions of families around the world and becomes more common as people grow older.
Doctors have effective ways to diagnose dementia after memory problems begin, but predicting who will develop the disease years earlier remains much more difficult.
Researchers are therefore looking for simple tests that can reveal hidden changes inside the brain before symptoms appear.
A new study led by researchers from the University of California, San Francisco and Beth Israel Deaconess Medical Center suggests that the answer may come from something people do every night: sleep.
The team used artificial intelligence to study brain wave recordings collected while people slept, and the results were published in JAMA Network Open.
Every sleeping brain produces electrical signals that change throughout the night. These signals can be recorded using EEG, a safe and painless test that places small sensors on the scalp.
Instead of examining only common sleep measurements, the researchers looked at tiny patterns that are usually too complex for humans to analyze by themselves.
The AI program combined thirteen different brain wave features to estimate how old each person’s brain appeared. This estimated brain age was then compared with the person’s actual age. A larger gap between the two measurements suggested that the brain was aging faster than expected.
To test the system, the scientists analyzed data from roughly seven thousand adults who did not have dementia when the studies began. Participants were between forty and ninety-four years old and were followed for many years. Around one thousand people eventually developed dementia, allowing the researchers to compare early brain wave patterns with later health outcomes.
The findings showed a clear trend. Every ten-year increase in estimated brain age compared with real age increased the chance of developing dementia by nearly forty percent. In contrast, people whose brains appeared younger than expected were less likely to develop the condition.
The study also highlighted why sleep is so important for brain health. Certain brain waves, including deep-sleep delta waves and sleep spindles, are closely linked with learning and memory.
The researchers also found that a brain wave feature called kurtosis was connected with a lower dementia risk, providing another clue about healthy brain function.
One encouraging result was that the AI prediction remained accurate even after accounting for many other factors, including smoking, exercise, education, body mass index, medical conditions, and genetic risk. This means the sleep-based brain age score appears to provide additional information rather than simply reflecting these well-known risk factors.
The scientists believe this technology could eventually become part of wearable sleep monitors that people use at home. Such devices might help doctors identify high-risk individuals years before noticeable memory loss begins. Earlier identification could encourage healthier lifestyles, better treatment of sleep disorders, and closer medical follow-up.
If you care about dementia, please read studies that eating apples and tea could keep dementia at bay, and Olive oil: a daily dose for better brain health.
For more health information, please see recent studies what you eat together may affect your dementia risk, and time-restricted eating: a simple way to fight aging and cancer.
