Printing temporary tattoos on people’s heads could make it easier to analyze their brain waves.
Electroencephalography (EEG) is a method of measuring electrical activity in the brain through electrodes placed on the scalp. It can be used to test patients for neurological conditions such as epilepsy, tumors, and damage from stroke or head trauma.
Because human skulls vary in size and shape, technicians must spend considerable time measuring and marking the scalp to obtain accurate values. The gel helps the electrodes detect brain signals, but when it dries it stops working. The cables that connect to the electrodes can also cause discomfort and interfere with delicate electrical signals.
Nanshu Lu and his team at the University of Texas at Austin hope to get around this problem by printing temporary tattoos on test subjects’ scalps. Tattoo ink is made of two polymers called poly(3,4-ethylenedioxythiophene) (PEDOT) and polystyrene sulfonic acid (PSS). It has excellent conductivity and durability, and does not irritate the skin.
A computer program creates a personalized tattoo design based on a 3D scan of your scalp, and a printer controlled by a robotic arm applies ink directly to your scalp. The ink comes in two different formulations, one for the electrodes that receive brain signals and one for the connection that goes to the back of the neck. From there, physical wires transmit the signal to small devices that record the data.
“Our technology embodies the first hair-compatible temporary electronic tattoo that enables high-quality brain monitoring,” says Lu.
This tattoo has been found to be effective for people with bald heads or buzz-cut hairstyles. “This method has not yet been extensively tested on long, thick, curly hair, but it could be improved in the future by changing the nozzle design or incorporating robotic fingers into the hair parting. “It could be possible,” she says. The researchers say it is also possible to make the process completely wireless by embedding a data transmitter into the tattoo.
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(Tag translation) Neuroscience