Brain-computer interface trials are taking off

This week, I covered the story of Casey Harrell—a man with ALS who is “the first power user” of a brain implant, according to the researchers who worked with him. Harrell is paralyzed and unable to speak coherently without the device. He has now spent almost three years using a brain-computer interface (BCI) that enables him to “speak,” surf the web, and perform his job as a climate activist, largely independently. Since Harrell was implanted with the device, in July 2023, a team at the University of California, Davis, has worked with him to adjust and improve its offerings. They’ve refined its accuracy, for example. And they’ve introduced settings including a privacy mode and a “profanity filter” that lets Harrell talk to his daughter without risking accidental swearing. Harrell told me that, for him, the device is “nothing short of revolutionary!” It has enabled him to maintain an income, reconnect with friends and family, and read to his daughter. The team that developed his BCI is one of several working on ways to use technology to allow people with paralysis to communicate, engage with the online world, and regain some independence. And Harrell is one of a growing number of people volunteering their brains to, as he puts it, “pay it forward and do the scientific research … [and] get some personal benefit.” Over the past couple of years, the number of BCI trial volunteers has soared. This year, China became the first country to approve a BCI for medical use. Advances in technology are allowing engineers to provide more features than ever. BCI research is properly taking off. I should first point out that BCIs come in different forms. Harrell’s device includes a set of electrodes embedded in his brain that pick up the electrical activity associated with speech. Those electrodes are connected to two docking ports on top of his head that can be plugged into a computer. That computer is loaded with software trained to decode his brain signals into phonemes (units of