Advances in brain-computer interface (BCI) technology are opening new frontiers in medicine and consumer electronics, enabling people with paralysis and other neurological conditions to regain communication and control. Yet these developments also raise profound ethical and privacy concerns, especially as artificial intelligence (AI) increasingly enhances the ability of BCIs to decode thoughts and intentions. Experts warn that without careful regulation, these technologies could infringe on mental privacy and personal autonomy in unprecedented ways.
One poignant example of BCI’s potential and challenges is the story of Nancy Smith, who was left paralyzed from the neck down after a car accident in 2008. Once an avid pianist, years later Smith was able to play music again using an implant that recorded and interpreted her brain activity. By imagining playing an on-screen keyboard, her brain signals were translated into keystrokes, producing simple tunes like “Twinkle, Twinkle, Little Star.” Remarkably, Smith felt as if the piano was playing itself—the system anticipated her intentions hundreds of milliseconds before she consciously tried to play, illustrating how BCIs can tap into preconscious brain activity. Smith’s implant was part of a clinical trial led by neuroscientist Richard Andersen at Caltech, who believes that implants targeting brain regions involved in reasoning and planning, beyond the motor cortex, can significantly improve prosthetic device performance.
Smith’s case is one of about 90 people worldwide who have received BCIs to control assistive technologies such as robotic arms, synthetic voice generators, or computers, often individuals paralysed by spinal cord injury, stroke, or neuromuscular diseases like ALS. Most current BCIs decode signals from the motor cortex linked to imagined movement, translating them into commands for external devices. However, Andersen’s work with dual implants accessing the posterior parietal cortex—a region involved in attention and planning—demonstrates that there is a rich variety of brain signals that can be decoded, potentially offering more nuanced control.
This ability to access a person’s innermost thoughts, including preconscious intentions, amplifies concerns about privacy and autonomy. As AI becomes more sophisticated at decoding neural data, the risk arises that BCIs could not only read thoughts but also influence or manipulate them. Beyond implanted devices, consumer neurotechnology products that use non-invasive methods like electroencephalography (EEG) are becoming more common. These devices are often embedded in stylish headbands or headphones and measure electrical activity across large populations of neurons from outside the skull. Although less precise than implanted BCIs, consumer EEG devices can provide information about general brain states such as focus, alertness, anxiety, or fatigue, and are marketed to enhance meditation, productivity, or athletic performance.
AI has played a key role in improving the quality of EEG data, which historically has been noisy and difficult to interpret in real-world settings. Companies like Neurable in Boston have developed algorithms that make EEG data more reliable for everyday use. Experts anticipate that future AI advances will enable these devices to decode subtle mental processes, such as rapid brain responses to stimuli that reveal attention or decision-making patterns. Thousands of users already employ consumer neurotech headsets, and major tech firms like Apple are exploring EEG sensors for integration into popular products such as wireless earphones.
However, while clinical BCIs are subject to strict medical regulation and privacy standards, consumer neurotechnology operates in a largely unregulated "wild west" of data governance. Studies have shown that many consumer BCI companies lack secure data-sharing protocols and state-of-the-art privacy protections. A 2024 analysis by the Neurorights Foundation found that nearly all such companies maintain full control over user data, including rights to sell it. This raises alarms among ethicists who fear that neural data could be combined with other digital information to infer sensitive details about individuals’ mental health, political beliefs, or other private characteristics, potentially enabling discrimination or manipulation.
Some governments have started to respond. Chile and several US states have enacted laws granting nerve activity recordings special protections. Yet experts like Marcello Ienca and Nita Farahany argue these laws are insufficient because they focus on raw neural data rather than the inferences that can be drawn from it. They warn that adding neural data to the existing data economy, which already compromises privacy and cognitive liberty, is akin to “giving steroids” to an already invasive system.
International bodies such as UNESCO and the OECD have issued guidelines on these emerging issues, and US senators have proposed legislation to task the Federal Trade Commission with reviewing