sensory feedback

Sensory feedback is giving the user a felt sense of what a BCI-controlled device is doing — how hard it is gripping, where it is, what it is touching. Without it, controlling a robotic hand is like trying to pick up an egg with a numb, gloved hand while looking away: possible, but slow and clumsy.

Our own movements rely on a constant stream of touch and position signals coming back from the body; that quiet feedback is what makes reaching and grasping feel effortless. A BCI that only sends commands out, with nothing coming back, leaves the user controlling blind and leaning entirely on their eyes.

So engineers add a return channel. They might stimulate the sensory cortex or a nerve to create a sense of touch, or use vibration on the skin as a stand-in. The closer that artificial feeling comes to the real thing, the more natural and precise the control becomes.