A new study has found that calculating "brain age" by analyzing brainwaves during sleep can predict dementia risk. The research also confirmed that the older one's brain age is relative to actual age, the higher the risk of dementia.
A joint research team from the University of California, San Francisco (UCSF) and Beth Israel Deaconess Medical Center recently analyzed sleep brainwave data from approximately 7,000 adults aged 40 to 94 using machine learning, according to the medical community on Wednesday.
None of the participants had been diagnosed with dementia at the start of the study. Over a follow-up period of 3.5 to 17 years, approximately 1,000 were newly diagnosed with dementia. The team applied a machine learning model integrating 13 subtle brainwave patterns, confirming that it could more precisely reflect brain health conditions that are difficult to capture with conventional indicators such as sleep duration and sleep efficiency.
The key finding was the correlation between brain age and dementia risk. For every 10 years that brain age exceeded actual age, dementia risk increased by approximately 40%. Conversely, those whose brain age was lower than their actual age showed lower dementia risk. This association remained statistically significant even after adjusting for education level, smoking, body mass index (BMI), physical activity and genetic factors.
The brainwave patterns that influenced brain age included delta waves occurring during deep sleep and sleep spindles involved in memory formation. The study also found that higher levels of "kurtosis" — sudden sharp signal spikes in brainwaves — were associated with lower dementia risk.
The research team suggested that since sleep brainwaves can be measured non-invasively, wearable devices could potentially be used for early prediction. They also noted that improving sleep quality could affect brain aging. Previous research has shown that treating sleep disorders such as sleep apnea can alter brainwave patterns.
"Lifestyle improvements such as reducing sleep apnea risk through weight management and exercise can help," the researchers said. "There is no magic pill that can improve brain health all at once."
The study was published in JAMA Network Open.
