Brain-computer interfaces are “connecting” to reality

An was paralyzed by a stroke, and she used a brain-computer interface to convert brain signals into the language and movements of a virtual character. Image source: Nature website

In a lab in San Francisco, California, a 47-year-old Canadian woman named Ann sits in front of a large screen. On the screen is an avatar that looks a lot like her. When Ann wants to speak, this "digital avatar" speaks for her, using her own voice. In 2005, a devastating stroke left Ann almost completely paralyzed, and she has been speechless for 18 years. Now, with the help of a brain-computer interface (BCI), Ann can finally "speak".

In 2022, Edward Zhang, a neurosurgeon at the University of California, Los Angeles, placed 253 electrodes on the surface of An's brain in areas related to speech. When An tried to speak, the brain-computer interface intercepted brain signals and converted them into words and speech. The system can convert speech to text at a speed of 78 words per minute, which is not as fast as the average speed of 150 words per minute for regular speech, but it is a great improvement over previous BCI technology.

The study, published earlier this year in the journal Nature, is one of several that have sparked interest in implantable BCIs in 2023. Meanwhile, other companies in the field are also making strides. For example, Neuralink, a neurotechnology company founded by entrepreneur Elon Musk, is recruiting paralyzed patients to participate in the first trials of its implantable BCIs.

Two brain-reading technologies

All brain-reading technologies, whether implantable or non-implantable, are based on the same basic principle: They record neural activity associated with functions such as speech or attention, "translate" the meaning of that activity, and use it to control external devices or simply provide it to the user as information.

Implantable BCIs can record more information-rich brain signals than non-implanted ones. Most non-implanted BCIs place electrodes on the scalp and use the "electroencephalogram" (EEG) method to detect tiny electric fields passing through the skull. These electric fields reflect the average discharge of millions of neurons distributed over a large number of brain areas.

Implantable technology in development

Many companies are developing and commercializing implantable BCIs.

Black Rock Neurotech, ParadRomics, and Neuralink have developed electrode systems that can penetrate the cerebral cortex and record information from individual neurons. The interfaces of these companies are grids composed of hundreds of rigid, straight electrodes, and multiple arrays can be implanted in a single person.

So far, Neuralink's implants consist of multiple long, flexible polymer threads. These electrodes contain many recording sites and are implanted deeper into the cortex than rigid electrode arrays.

Instead, Synchron and Precision Neurosciences are working with electrodes placed on the surface of the brain. Synchron's BCI device contains only 16 electrodes, bucking the trend toward greater bandwidth, and its implantation does not require neurosurgery, but the low bandwidth means the device cannot decode a person's thoughts.

Non-implantable devices focus on consumers

Developers of non-implantable consumer headsets face a different set of obstacles. The Nature website points out that EEG is limited in that it cannot decode the user's thoughts, but is better at indicating a person's overall mental state.

Several companies have developed EEG sensing products such as headbands and headphones. These products can push users into a deeper state of meditation or help people enter a more focused and efficient state. In 2022, Liverpool Football Club announced that the products of German neurotechnology company Neuro11 can help players stay calm and focused under stressful situations.

Some products aim to manipulate brain waves directly, hoping to change the user's mental state. The British startup Neudio uses an algorithm to record the user's EEG and generate synthetic music in real time, aiming to guide brain activity to relax or focus. Other companies are also using similar methods to improve sleep quality.

Meanwhile, Metaverse and Apple have launched head-mounted devices that include eye-tracking technology, and in July, Apple was awarded a patent for integrating EEG sensors into AirPods headphones.

Ethical and legal issues cannot be ignored

As the development of brain-reading neurotechnology accelerates, ethicists and regulators are increasingly questioning the unique risks these devices pose.

Rafael Yost, a neuroscientist at Columbia University in the United States, said that the brain is the organ that produces human thoughts and is a part of the body. It should be a shelter for human identity.

The Nature website points out that implantable medical technology may raise ethical issues. For example, considering that artificial intelligence software helps to translate the user's brain activity into decisions, there are questions about the user's rights and responsibilities. Regarding non-implanted devices, there are still questions about the quality of EEG signals recorded by consumer devices. These technologies may not only mean new ways to enhance personal computing experience, but also raise the question of whether a person's brain data, or even mental privacy, will be commercialized.

Chile is currently the only country in the world to have legislation protecting neuro-rights, and governments in Brazil, Mexico, Spain and Australia are discussing how to enact neuro-technology-related legislation.