Mastering the Brain-Computer Interface

At Johns Hopkins University, engineers are learning to translate between the neural signals of the brain and the machine language of a prosthetic arm

4 min read

The first human clinical trials of a brain implant intended to control a prosthetic arm are slated for 2009 at the Johns Hopkins University Biomedical Instrumentation and Neuroengineering Laboratory, in Baltimore. In one brightly lit room, a young volunteer named Rob Rasmussen sits with his head strapped into a tight-fitting cap, inside which 64 electrodes monitor his brain waves. The electrodes detect the electrical activity caused by neurons firing inside the motor areas of his brain and send the raw impulses to a nearby instrument to be digitized. The digitized signals are translated into real-time traces that scrawl across two wide-screen monitors. One of the monitors shows the 64 simultaneous channels of brain-wave recordings. The other, larger monitor is devoted to two entirely different traces--those of the mu bands. These are the keys to controlling a prosthetic arm with the mind.

Mu bands are an abstract feature of the brain waves picked up by the electrodes: they provide a broad reflection of what's happening in the motor areas of the brain. In this case, they characterize what Rasmussen is thinking about doing with his hands. The mu bands maintain a regular rhythm that desynchronizes in the left side of the brain when you wiggle a finger or arch your foot on the right side of your body (and vice versa). That rhythm also responds the same way--and this is key--to merely thinking about doing those things. So to disturb the waves of his mu bands, Rasmussen thinks about moving his hands. To let the waves return to their natural rhythm, he stops thinking about moving his hands. His actual hands are resting lightly on the arms of his chair. They don't even twitch.

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A New Treatment for Arthritis: Vagus-Nerve Stimulation

Studies will soon show whether electroceuticals outperform pharmaceuticals

5 min read
A tablet computer, a smartphone, a grey belt with white stripes, a grey disc, and a small silver rectangle with a wire curled beside it.

Galvani’s system includes a nerve stimulator that attaches to the splenic nerve.

Galvani Bioelectronics

Monique Robroek once had such crippling arthritis that, even with the best available medications, she struggled to walk across a room. But thanks to an electronic implant fitted under her skin, she managed to wean herself off all her drugs and live pain-free for nearly a decade—until recently, when a viral illness made her rheumatoid arthritis (RA) flare up again.

This article is part of our special report Top Tech 2023.

Robroek’s long remission is “very impressive” and rare among patients with RA, says her doctor Frieda Koopman, a rheumatologist at Amsterdam UMC, in the Netherlands. Robroek’s experience highlights the immense potential of so-called bioelectronic medicine, also known as electroceuticals, an emerging field of treatment for diseases that have traditionally been managed with pharmaceuticals alone.

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