A chip in the brain restores his voice: the breakthrough that changes the lives of ALS patients

A new study on brain-computer interfaces (BCI) opens important prospects for people affected by severe motor limitations. A study published in Nature Medicine demonstrates that a man suffering from amyotrophic lateral sclerosis (ALS) has been able to use a BCI system in his home to communicate, work, and interact with the digital world without the constant presence of researchers.

The technology was developed by the University of California, Davis, along with collaborators from Brown University and the Mass General Brigham Neuroscience Institute. The device leverages advanced algorithms capable of interpreting brain activity and transforming it into written text or commands to move a cursor on the screen. The system was created with the aim of recovering some functions lost due to paralysis by translating brain signals associated with attempts to speak and move.

In the past, similar tools had shown promising results, especially in controlled laboratory environments, but long-term daily use still posed a challenge.

The main subject of the study and the results obtained on the brain-computer interface

The main subject of the study is Casey Harrell, a 47-year-old man involved in the BrainGate2 clinical trial. Due to ALS, he experiences severe limb weakness and difficulty with speech. In 2023, a device was implanted in the brain region linked to speech production, equipped with four small arrays containing 256 electrodes that can record neuronal activity.

For almost two years, Harrell has used the system in his home for over 3,800 hours, communicating more than 183,000 phrases and about two million words. The average speed reached was approximately 56 words per minute, with a progressive improvement over time. During the tests, the system demonstrated high reliability: Harrell judged 92% of the produced sentences as correct or nearly correct, while in controlled trials, over 99% accuracy was recorded on words using a very broad vocabulary.

Thanks to the BCI, the patient can write emails, send messages, browse online, and maintain relationships with family and colleagues. Researchers emphasize that this experience represents an important step toward devices that are truly usable in daily life.