Sensory substitution

Delivering information belonging to one sensory modality through a different, intact modality, so the nervous system learns to read it. Classic examples include rendering a camera image as an electrotactile pattern on the tongue or back, or conveying prosthetic grip force through a vibrotactile array on residual skin. Because it stimulates existing sensory surfaces, no cortical implant is required.

Sensory substitution relies on cross-modal plasticity: with training, the substituted signal can become intuitive rather than requiring conscious decoding. Its advantages are non-invasiveness and safety; its costs are limited information bandwidth, a learning burden, and a feeling that is referred to the wrong place (the tongue, the back) rather than to the acting hand. It is often the pragmatic feedback route when ICMS is unavailable.