A man who lost the ability to speak can now hold real-time conversations and even sing through a brain-controlled synthetic voice. The brain-computer interface reads the man's neural activity via electrodes implanted in his brain and then instantaneously generates speech sounds that reflect his intended pitch, intonation and emphasis. Restoring the brain's mitochondria could slow ageing and end dementia "This is kind of the first of its kind for instantaneous voice synthesis – within 25 milliseconds," says Sergey Stavisky at the University of California, Davis. The technology needs to be improved to make the speech easier to understand, says Maitreyee Wairagkar, also at UC Davis. But the man, who lost the ability to talk due to amyotrophic lateral sclerosis, still says it makes him "happy" and that it feels like his real voice, according to Wairagkar.

Maitreyee Wairagkar is a postdoctoral fellow at University of California, Davis, developing assistive neurotechnology using artificial intelligence to restore lost function in people with neurological disorders. She builds brain-computer interfaces to enable people with severe motor and speech impairments to communicate directly via their brain signals by breaking barriers between humans and technology. Previously, she was at Imperial College London and UK Dementia Research Institute where she developed conversational AI and social robots for dementia support.