Revolutionary E-Tattoo Monitors Mental Workload, Promising Safer High-Stakes Professions

'E-tattoo' could track mental workload for people in high-stake jobs, study says

Scientists say device could alert workers such as pilots and healthcare staff when they are feeling the strain Whether it is doing sums or working out what to text your new date, some tasks produce a furrowed brow. Now scientists say they have come up with a device to monitor such effort: an electronic tattoo, stuck to the forehead. The researchers say the device could prove valuable among pilots, healthcare workers and other professions where managing mental workload is crucial to preventing catastrophes. "For this kind of high-demand and high-stake scenario, eventually we hope to have this real-time mental workload decoder that can give people some warning and alert so that they can self-adjust, or they can ask AI or a co-worker to offload some of their work," said Dr Nanshu Lu, an author of the research from the University of Texas at Austin, adding the device may not only help workers avoid serious mistakes but also protect their health. Writing in the journal Device, Lu and colleagues describe how using questionnaires to investigate mental workload is problematic, not least as people are poor at objectively judging cognitive effort and they are usually conducted after a task. Meanwhile, existing electroencephalography (EEG) and electrooculography (EOG) devices, that can be used to assess mental workload by measuring brain waves and eye movements respectively, are wired, bulky and prone to erroneous measurements arising from movements. By contrast, the "e-tattoo" is a lightweight, flexible, wireless device. The black, wiggly path of the e-tattoo is composed of a graphite-based conductive material, and is attached to the forehead using conductive adhesive film. Four square EEG electrodes, positioned on the forehead, each detect a different region of brain activity - with a reference electrode behind the ear - while rectangular EOG electrodes, placed vertically and horizontally around the eyes, provide data about eye movements. Each of the stretchable electrodes is coated in an additional conductive material. The e-tattoo, which is bespoke and disposable, is connected to a reusable flexible printed circuit using conductive tape, while a lightweight battery can be clipped to the device. After finding the e-tattoo worked as well as traditional EEG and EOG devices for monitoring brain waves and eye movements the team tested the technology on six participants. Each participant was shown a screen on which 20 letters flashed up, one at a time, at various locations. Participants were asked to click a mouse if either the letter itself, or its location, matched one shown a given number of letters (N) back. Each participant carried out the task multiple times, with the N value varying between 0 and 3 - corresponding to four levels of difficulty. The team found that as the task became harder, the different types of brainwave detected showed shifts in activity that corresponded to a greater mental workload. The team then fed the EEG and EOG data, together with the "N" numbers, into a machine-learning algorithm. After a training period, the researchers found the algorithm did better than chance at predicting the mental workload of a participant based on their EEG and EOG data alone. Lu said the full device -including chip and battery - was expected to cost less than $200 (£148). The team are now developing the approach so signals can be decoded by the device's microprocessor and sent to an app to alert the user if their mental workload is too high. But the remedy is not, necessarily, to switch to a simple task. "Previous studies indicated that the optimal mental performance occurs when the mental workload demand is not too low or too high," said Lu. "When it's too low, it's very boring, and the people will just lose focus."

Burning out? An e-tattoo can track mental strain

Ever thought so long and hard on a problem that your forehead grew hot, your brain became frazzled and your eyes grew bleary? A new temporary tattoo can help measure that sort of mental strain, researchers report. The wireless forehead electronic tattoo decodes brainwaves to measure mental strain and potential burnout without bulky headgear, researchers reported today in the journal Device. This e-tattoo could help improve safety among folks in jobs that require constant focus, like air traffic controllers or truckers, researchers said. "We've long monitored workers' physical health, tracking injuries and muscle strain," researcher Luis Sentis, a professor of engineering at the University of Texas at Austin, said in a news release. "Now we have the ability to monitor mental strain, which hasn't been tracked," he continued. "This could fundamentally change how organizations ensure the overall well-being of their workforce." There's a cognitive "Goldilocks zone" for humans, where they perform best when they're neither overwhelmed nor bored, researchers said in background notes. "There is an optimal mental workload for optimal performance, which differs from person to person," senior researcher Nanshu Lu, a professor of engineering at the University of Texas at Austin, said in a news release. The wireless e-tattoo consists of a lightweight battery back and paper-thin sticker-like sensors, researcher said. The sensors feature wavy loops and coils, which allows them to stretch and conform to a person's forehead for a clearer signal. The tattoo analyzes electrical activity from the brain much in the way that electroencephalography (EEG) caps do -- only better, researchers said. "What's surprising is those caps, while having more sensors for different regions of the brain, never get a perfect signal because everyone's head shape is different," Lu said. "We measure participants' facial features to manufacture personalized e-tattoos to ensure that the sensors are always in the right location and receiving signals." Researchers tested the e-tattoo on six people who completed a memory challenge that increased in difficulty. The tattoo captured increased theta and delta brainwave activity, which indicates cognitive demand, as well as decreasing alpha and beta brainwave activity indicating mental fatigue. Combined, these brainwave readings can show when the brain is struggling, researchers said. Researchers also trained an artificial intelligence (AI) program to predict a person's mental strain based on signals from the e-tattoo. The AI was able to distinguish between different levels of mental workload and predict when a person's brain was apt to pop. The e-tattoo is designed to be low-cost -- its chips and battery pack cost about $200, while disposable sensors are about $20 each. That's a steal compared to the $15,000 price tag for conventional EEG equipment, researchers said. "Being low cost makes the device accessible," Sentis said. "One of my wishes is to turn the e-tattoo into a product we can wear at home." Currently, the e-tattoo only works on hairless skin, but researchers are working to combine it with ink-based sensors that can work on a hairy scalp. This will allow for full head coverage and more comprehensive brain monitoring, researchers said.

Burning Out? An E-Tattoo Can Track Mental Strain

By Dennis Thompson HealthDay ReporterTHURSDAY, May 29, 2025 (HealthDay News) -- Ever thought so long and hard on a problem that your forehead grew hot, your brain became frazzled and your eyes grew bleary? A new temporary tattoo can help measure that sort of mental strain, researchers report. The wireless forehead electronic tattoo decodes brainwaves to measure mental strain and potential burnout without bulky headgear, researchers reported today in the journal Device. This e-tattoo could help improve safety among folks in jobs that require constant focus, like air traffic controllers or truckers, researchers said. "We've long monitored workers' physical health, tracking injuries and muscle strain," researcher Luis Sentis, a professor of engineering at the University of Texas at Austin, said in a news release. "Now we have the ability to monitor mental strain, which hasn't been tracked," he continued. "This could fundamentally change how organizations ensure the overall well-being of their workforce." There's a cognitive "Goldilocks zone" for humans, where they perform best when they're neither overwhelmed nor bored, researchers said in background notes. "There is an optimal mental workload for optimal performance, which differs from person to person," senior researcher Nanshu Lu, a professor of engineering at the University of Texas at Austin, said in a news release. The wireless e-tattoo consists of a lightweight battery back and paper-thin sticker-like sensors, researcher said. The sensors feature wavy loops and coils, which allows them to stretch and conform to a person's forehead for a clearer signal. The tattoo analyzes electrical activity from the brain much in the way that electroencephalography (EEG) caps do -- only better, researchers said. "What's surprising is those caps, while having more sensors for different regions of the brain, never get a perfect signal because everyone's head shape is different," Lu said. "We measure participants' facial features to manufacture personalized e-tattoos to ensure that the sensors are always in the right location and receiving signals." Researchers tested the e-tattoo on six people who completed a memory challenge that increased in difficulty. The tattoo captured increased theta and delta brainwave activity, which indicates cognitive demand, as well as decreasing alpha and beta brainwave activity indicating mental fatigue. Combined, these brainwave readings can show when the brain is struggling, researchers said. Researchers also trained an artificial intelligence (AI) program to predict a person's mental strain based on signals from the e-tattoo. The AI was able to distinguish between different levels of mental workload and predict when a person's brain was apt to pop. The e-tattoo is designed to be low-cost -- its chips and battery pack cost about $200, while disposable sensors are about $20 each. That's a steal compared to the $15,000 price tag for conventional EEG equipment, researchers said. "Being low cost makes the device accessible," Sentis said. "One of my wishes is to turn the e-tattoo into a product we can wear at home." Currently, the e-tattoo only works on hairless skin, but researchers are working to combine it with ink-based sensors that can work on a hairy scalp. This will allow for full head coverage and more comprehensive brain monitoring, researchers said.