A new study by the University of California, San Francisco (UCSF), and Beth Israel Deaconess Medical Center points to a potential key for understanding how the brain ages: sleep patterns.
Researchers examined brain-wave activity during sleep to identify individuals at higher risk of developing dementia, potentially years before symptoms appear.
Published in JAMA Network Open, the study used an AI model to estimate a person’s “brain age” from electroencephalogram (EEG) recordings collected during clinical sleep trials. When a person’s brain age exceeds their chronological age, the risk of dementia increases. Overall, the study found that for every 10-year gap between brain age and actual age, dementia risk rose by nearly 40%. Conversely, participants with a younger brain age had a lower risk of developing the disease.
The study analyzed data from more than 7,000 adults aged 40 to 94 who were enrolled in five longitudinal studies. At the outset, none of the participants had dementia. However, during follow-up periods ranging from 3.5 to 17 years, approximately 1,000 individuals developed the condition.
Using 13 microstructural features of sleep EEG patterns, the team uncovered insights that conventional sleep measures—such as total sleep time or sleep-stage percentages—often miss.
“Broad sleep metrics don’t fully capture the complex multidimensional nature of sleep physiology,” said Yue Leng, MBBS, PhD, associate professor of psychiatry at UCSF School of Medicine and senior author of the study.
Brain-Wave Sleep Patterns
The team identified several notable patterns in sleep-related brain activity. Deep sleep is characterized by delta waves, while brief bursts of rapid brain activity known as sleep spindles are associated with memory processing. Both features proved important in estimating “brain age.” Interestingly, sudden large spikes in brain activity—referred to as kurtosis—were associated with a lower risk of dementia.
Even after accounting for lifestyle factors such as education, smoking, body weight, exercise, existing health conditions, and genetics, an older-appearing brain remained a strong predictor of future dementia risk.
Catching It Early
Early detection remains one of the most effective strategies for preventing disease progression. Because EEG recordings are noninvasive, researchers say that estimating brain age from sleep signals could eventually be performed outside clinical settings using wearable devices.
“Brain age is calculated from sleep brain waves,” Leng explained. “We know that brain activity during sleep provides a measurable window into how well the brain is aging
Improving your sleep can also improve your brain health, and previous research has shown that treating sleep disorders can help sleep-related brain-wave patterns.
“Better body management, such as lowering BMI and increasing exercise to reduce the likelihood of sleep apnea, may have an impact,” said Haoqi Sun, PhD, assistant professor of neurology at Beth Israel Deaconess and first author of the study.
“But there’s no magic pill to improve brain health,” Sun added.
Chrissy Newton is a PR professional and the founder of VOCAB Communications. She currently appears on The Discovery Channel and Max and hosts the Rebelliously Curious podcast, which can be found on YouTube and on all audio podcast streaming platforms. Follow her on X: @ChrissyNewton, Instagram: @BeingChrissyNewton, and chrissynewton.com. To contact Chrissy with a story, please email chrissy @ thedebrief.org.