A New Twist on Brain-Computer Interfaces

Brain-computer interfaces (BCIs) represent a groundbreaking field of technology that bridges the gap between the human brain and external devices. These interfaces enable direct communication between the brain and computers, allowing individuals to control machines and interact with technology using only their thoughts. BCIs have the potential to transform various aspects of human life, ranging from healthcare and communication to gaming and assistive technologies.

One of the most promising aspects of BCIs lies in the realm of healthcare. For individuals with severe motor disabilities, such as those with paralysis or locked-in syndrome, BCIs offer the possibility of restoring communication and mobility. These interfaces can allow users to control prosthetic limbs, robotic exoskeletons, or even wheelchairs with their thoughts, thus significantly improving their quality of life.

But the potential extends far beyond those with disabilities. In the gaming and entertainment industry, for example, BCIs open up a new dimension of immersive experiences. Players could interact with virtual environments, control characters, or manipulate objects in games using their minds, enhancing the overall gaming experience to unprecedented levels.

Given the broad applicability of this technology, making it as transparent to the user as possible is an important goal. However, at present, the most common types of devices are either cap- or headband-based, which are not entirely practical for normal, daily use. Alternatively, microneedle-based invasive methods may be leveraged, which can lead to inflammation risks and irreversible damage to soft tissues. To enable widespread adoption of BCI technologies, better options are clearly needed.

The BCI landscape may be about to undergo a significant change as the result of work recently done by a team led by researchers at Tsinghua University. They have developed a soft, conformal in-ear bioelectronic device that can stably record electroencephalogram (EEG) measurements. It is comfortable and adaptable to the unique anatomy of each individual, and critically, it does not interfere with normal hearing.

Called SpiralE, this corkscrew-shaped BCI is gently screwed into the ear canal where it adaptively expands along the auditory meatus under electrothermal actuation. This action ensures that the electrodes will make good contact with the skin surface, while minimizing friction against the wall of the ear canal. The center of the SpiralE is hollowed out to allow sound waves to pass through normally, and the soft material design prevents echoing that would otherwise distort sound.

To evaluate the effectiveness of SpiralE, a series of experiments were conducted. In the first trial, subjects were shown various visual patterns and asked to focus on them for a period of several seconds. Measurements were captured from the device during this time, and the results were compared with the patterns of brain activity that would be expected based on previous research. The observed data confirmed the effectiveness of the in-ear electrodes in all cases. Similar experiments were carried out with audio stimulation, which gave the team further confidence in their system.

The accuracy and discrete nature of the SpiralE technology has the potential to aid the development of user-friendly biomedical engineering and neuroscience applications in the near future. The research team sees many use cases, ranging from turning thoughts into text and controlling devices to virtual reality and memory augmentation.

The open access paper was recently published in Nature Communications.