A cutting-edge brain-computer interface (BCI) system has enabled a patient with Amyotrophic Lateral Sclerosis (ALS) to communicate with his family in real time using a synthesized voice. ALS is a progressive neurological disorder that affects nerve cells in the brain and spinal cord, leading to the loss of muscle control and, eventually, the ability to speak.

Developed at the University of California, Davis, the new BCI system was designed to support faster and more natural communication for individuals with severe paralysis. Unlike previous speech neuroprostheses that often introduce delays of several seconds, this new system enables near-instantaneous voice synthesis, making conversation feel much more natural and interactive.

The technology works by decoding brain signals through tiny microelectrode arrays surgically implanted into the region of the brain responsible for speech production. These 256 electrodes capture the activity of hundreds of neurons and transmit the signals to external computers that interpret and generate a synthesized voice.

During clinical trials, a 45-year-old participant took part in the BrainGate2 study conducted at UC Davis Health. To train the system, he was shown various sentences and instructed to attempt to speak them aloud. The sentences included different intonations, such as statements and questions, to help the system learn how speech patterns vary with meaning. As he attempted to speak, his brain activity was recorded and matched with intended vocalizations using advanced AI algorithms.

The result was a BCI that translated his brain signals into speech with a delay of only one-fortieth of a second—essentially as fast as hearing one’s own voice. This allowed for spontaneous, dynamic conversation, including the ability to adjust vocal pitch and even sing basic melodies.

The synthesized voice was intelligible enough that listeners correctly identified around 60% of the spoken words. The AI models driving this system are able to map neural signals to specific sounds in real time, preserving the rhythm and emotional tone of speech.

This new BCI system represents a major leap forward in assistive technology for individuals with neurological conditions. It offers not only a technical advancement but also a powerful emotional and social tool, restoring a critical element of human connection: the ability to speak.

By Impact Lab