CTRL-Labs’ work is built on a technology known as differential electromyography, or EMG. The band’s inside is lined with electrodes, and while they’re touching my skin, they measure electrical pulses along the neurons in my arm. These superlong cells are transmitting orders from my brain to my muscles, so they’re signaling my intentions before I’ve moved or even when I don’t move at all.
EMG is widely used to measure muscle performance, and it’s a promising option for prosthetic limb control. CTRL-Labs isn’t the first company to imagine an EMG-based interface, either. Canadian startup Thalmic Labs sells an EMG gesture-reading armband called the Myo, which detects muscle movements and can handle anything from controlling a computer to translating sign language. (CTRL-Labs used Myo armbands in early prototyping, before designing its own hardware.)
One issue is interference from what Bouton refers to as motion artifacts. The bands have to process extraneous data from accidental hand movements, external vibrations, and the electrodes shifting around the skin. “All those things can cause extra signal you don’t want,” he says. An electrode headset, he notes, would face similar problems — but they’re serious issues for either system.
Reardon says CTRL-Labs’ band can pick out far more precise neural activity than the Myo, which Thalmic bills as a muscle-reading system rather than a brain-computer interface. And the band is supposed to work consistently anywhere on the wrist or lower arm, as long as it’s fitted snugly. (The prototype felt like wearing a thick, metallic elastic bracelet.) But Bouton, who uses EMG to find and activate muscles of people with paralysis, says users would get the best results from hitting exactly the same spot every time — which the average person might find difficult. “Even just moving a few millimeters can make a difference,” he says
Long, fascinating profile of CTRL-Labs. I saw them presenting in NYC at the O’Reilly AI Conference, when they announced the availability of their wristband within this years.