A temporary electronic “tattoo” that monitors brainwaves and sounds an alarm when your mind is working too hard — or not hard enough — has been developed by researchers.
The device, which is worn on the forehead and face, is designed to detect when the brain is under strain. It monitors patterns of electrical activity in the brain using a technique known as electroencephalography (EEG), as well as the movements of the eyes, offering what the researchers describe as an objective and minimally invasive way to assess mental effort.
They believe that it could be particularly useful in professions such as air traffic control or medicine, where lapses in concentration can have serious consequences.
Paper-thin sensors conform comfortably to the skin and move with it
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Dr Nanshu Lu, of the University of Texas at Austin, the study’s lead author, said: “Technology is developing faster than human evolution. Our brain capacity cannot keep up and can easily get overloaded.
“There is an optimal mental workload for optimal performance, which differs from person to person.”
At present, the gold standard for measuring mental workload is the Nasa Task Load Index — a questionnaire that workers, including astronauts, fill in after completing a task. While useful, it only offers an insight once a job has been completed. By contrast, the e-tattoo aims to deliver continuous, real-time data.
Luis Sentis, of the University of Texas, a co-author of the research, said: “We’ve long monitored workers’ physical health, tracking injuries and muscle strain. Now we have the ability to monitor mental strain, which hasn’t been tracked. This could fundamentally change how organisations ensure the overall wellbeing of their workforce.”
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The device consists of a small battery pack worn behind the ear and paper-thin sensors designed with wavy loops and coils to conform comfortably to the skin and to move with it. The sensors pick up on electrical activity from the brain — a job normally done via EEG by having a participant wear a cap embedded with electrode sensors.
In tests, participants completed a memory task that gradually increased in difficulty. As cognitive demand rose, their brainwaves exhibited a distinct pattern: higher theta and delta wave activity, which is associated with increased mental effort, and decreased alpha and beta waves, which are often linked to mental fatigue.
The team trained a computer model to predict mental workload based on these signals, successfully distinguishing between levels of cognitive strain. Whereas conventional EEG systems can cost more than $15,000, the e-tattoo’s battery and chips are about $200, and the disposable sensor patches approximately $20 each.
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Sentis said: “Being low cost makes the device accessible. One of my wishes is to turn the e-tattoo into a product we can wear at home.”
