Earbuds may soon do much more than play music or take phone calls.
According to a new international study, the same devices millions of people wear every day could one day help monitor brain health and mental workload simply by tracking subtle changes in hearing.
Researchers discovered that commercially available earbuds have the potential to detect brain activity by measuring tiny responses inside the ear.
These responses reflect how hard the brain is working, a concept known as cognitive load.
Cognitive load influences how well we learn, perform tasks, and cope with stress, and it may also provide early clues about cognitive decline.
The project was led by scientists from the University of Melbourne, University College London, Nokia Bell Labs at Cambridge University, and the University of Washington.
Their findings were presented at the 2025 ACM International Joint Conference on Pervasive and Ubiquitous Computing.
To test the idea, the team used acoustic sensors built into earphones to measure faint sounds produced by the inner ear, called otoacoustic emissions.
These sounds are linked to activity in the brain and nervous system. By analyzing them, the researchers could estimate how mentally strained a person was during different tasks.
Nineteen adults aged 20 to 55 took part in the experiment. The researchers created listening tasks designed to produce different levels of mental effort. Participants wore a prototype ear device equipped with a small speaker and a sensitive microphone.
At the same time, they also wore EEG headsets, which measure electrical brain activity, to confirm the accuracy of the ear-based readings.
Using artificial intelligence, the team developed a model that could classify the participants’ mental effort into four levels, from low to high cognitive load. They found that as mental workload increased, the ear became more sensitive to sound in specific ways. These patterns differed depending on factors such as age and gender, suggesting that the technology could eventually be personalized for individuals.
Scientists believe this approach could have many real-world uses. In education, it might help identify when students are overwhelmed or ready to absorb more information. In high-risk fields like aviation, health care, or the military, it could warn when workers are mentally overloaded and at risk of mistakes. It may also improve how computers and devices respond to users by adjusting to their mental state.
Researchers say ear-worn devices are quietly evolving into powerful health tools. Some earbuds already track movement and heart rate, and brain monitoring could be the next step. In the future, your earbuds might alert you when you are too stressed, mentally fatigued, or struggling to concentrate.
The team plans to test the technology on larger and more diverse groups of people and explore ways to improve accuracy.
While more research is needed, the findings suggest a future where everyday gadgets could help monitor brain health in real time, offering early warnings and helping people manage their mental well-being more effectively.
