Casey Harrell using a brain-implant interface, with his wife and daughter nearby. (UCD)
A man with severe paralysis, who can no longer move almost any part of his body, can now 'speak' on his own terms, using an experimental brain implant.His family can finally hear his voice again, as a digital version reads his thoughts aloud.Casey Harrell has an advanced form of amyotrophic lateral sclerosis (ALS), which makes his natural speech very difficult for others to understand.But he has a lot to say when given the opportunity.For nearly two years, the 47-year-old's brain has been hooked up to a continuously running brain-to-text decoder using an experimental neuroprosthetic. This cutting-edge interface has allowed Harrell to express more than 183,000 sentences and close to 2 million words.An illustration of the brain-computer interface, which decodes neural activity (b) into words on a screen that users can rate or correct (c) before the text is verbalized. The system has eye-gaze tracking to enable the participant to select on-screen buttons. (Card et al., Nature Medicine, 2026)The futuristic technology requires a surgical implant in a specific part of the brain. The electrode arrays placed therein can detect neurological activity when someone attempts to speak, even if that person does not move their mouth. This data is then automatically detected by an external speech decoder and displayed on a computer screen in real time.Harrell navigates the screen with his eye gaze. His focus is represented as a white circular 'cursor', and he can 'click' using the mere thought.It takes a bit of time to connect the device in the morning, with some help from a carer, but mounted on a mobile cart, the decoder can follow Harrell throughout his day.Using it, he can independently send emails and messages, browse the internet, and maintain full-time employment, despite his condition.Perhaps most importantly, he can communicate with loved ones. The digital voice that verbalizes his thoughts was made to sound similar to Harrell's pre-ALS voice."It is very sweet to have the ability to look at my wife's eyes when she hears my voice," Harrell has shared through the system, "and conjures up a sweet memory and to explain to my daughter who does not really remember anything about when I was still talking to them and remind them of what I used to sound like."The outcome has been life-changing, and we know that because Harrell has told us so.In the video below, Harrell explains via text that the technology is enabling him "to do so very much and stay tethered to my life as a human being."
