A Good Hair Day and a Great Brain Scan

Controlling computers and other devices with the mind is the dream of technophiles everywhere. In order to do that, we first have to be able to determine what someone is thinking. Today’s best methods are coarse, capturing only general areas of activity in the brain — but that is good enough for many applications. Even still, few interfaces of this sort exist, and none have been widely adopted. This is because the sensing systems are cumbersome and, to put it mildly, not very stylish.

Of the noninvasive options available, bulky helmets and caps with electrodes and wires running every which way are the norm. Since no one wants to look like Doc Brown wearing his mind-reading helmet, these are not seen outside of laboratory settings. This is a shame, not only because of the intuitive control of electronic devices that these systems could offer, but also because they can be used to diagnose a number of neurological conditions.

Penn State researchers have taken a step toward a future in which brain activity can be captured without cumbersome or unfashionable headgear. They have developed tiny electrodes that can be attached directly to the scalp. Thin wires extend from these electrodes in a way that resembles hair, which causes them to blend in and become virtually invisible. By connecting these wires to an electroencephalography (EEG) machine, electrical signals from the brain can be captured.

Traditional EEG systems use rigid metal electrodes affixed to the scalp with conductive gels, along with a jungle of wires connecting to machines that display brain wave patterns. These systems, while effective, are uncomfortable and unsuitable for long-term wear.

The new design replaces the traditional setup with a flexible, lightweight device made from a 3D-printed hydrogel material. Each electrode is attached via a bioadhesive ink that sticks directly to the scalp, eliminating the need for gels or other skin preparations. This allows the electrodes to maintain close contact with the skin even through hair, vastly improving signal quality without causing irritation.

The device has been shown to perform on par with gold-standard EEG electrodes, providing stable, high-quality recordings for more than 24 continuous hours. Unlike conventional systems, it does not need frequent reapplication, and it does not shift or degrade in quality as the user moves. The strong adhesion and stretchable design keep the electrodes in place during everyday activities — even while putting on a hat or combing one’s hair.

Although the current system still requires a wired connection to EEG recording equipment, the team is working toward a fully wireless version. Such a system could allow users to go about their daily routines while their brain activity is monitored in real time, opening doors for everything from neurological diagnostics to brain-computer interfaces. EEG technology may finally be close to moving out of the lab and into everyday life.