A novel device designed to help stroke patients recover wrist and hand function has been approved by the US Food and Drug Administration (FDA). Called IpsiHand, the system is the first brain-computer interface (BCI) device to ever receive FDA market approval. The IpsiHand device consists of two separate parts – a wireless exoskeleton that is positioned over the wrist, and a small headpiece that records brain activity using non-invasive electroencephalography (EEG) electrodes. The system is based on a discovery made by Eric Leuthardt and colleagues at the Washington University School of Medicine over a decade ago. It is well known that each side of the brain controls movement on the opposite side of the body, so if a stroke damages motor function on the right side of the brain movement on a person's left side will be affected.

Dr Eric C Leuthardt, 45, is a neurosurgeon at Washington University in St Louis. He is also the co-founder of NeuroLutions, a research laboratory developing direct interfaces between mind and computer. Leuthardt is pioneering the use of electrical brain implants to help restore motor function to the paralysed limbs of stroke victims. He is also helping to develop electrode systems that can directly decode the unspoken "inner voice" of the mind, and use it to direct external action; for example, Leuthardt's subjects have been able to control the cursor of a Space Invaders video game just by thinking. He has published two science fiction novels aimed at "preparing society for the changes" that his work predicts.

It's the Monday morning following the opening weekend of the movie Blade Runner 2049, and Eric C. Leuthardt is standing in the center of a floodlit operating room clad in scrubs and a mask, hunched over an unconscious patient. "I thought he was human, but I wasn't sure," Leuthardt says to the surgical resident standing next to him, as he draws a line on the area of the patient's shaved scalp where he intends to make his initial incisions for brain surgery. "Did you think he was a replicant?" "I definitely thought he was a replicant," the resident responds, using the movie's term for the eerily realistic-looking bioengineered androids. "What I think is so interesting is that the future is always flying cars," Leuthardt says, handing the resident his Sharpie and picking up a scalpel. "They captured the dystopian component: they talk about biology, the replicants. But they missed big chunks of the future. Where were the neural prosthetics?"