Restorative vs assistive BCI

A framing distinction that organizes the whole rehabilitation field. An assistive (substitutive) BCI provides a permanent output channel that bypasses the injury — a decoded cursor, robotic arm, or speech synthesizer the user relies on indefinitely — and success is measured by how well it works while worn. A restorative (rehabilitative) BCI instead aims to change the nervous system so that native function returns, and success is measured by lasting improvement after the device is switched off or removed. The same hardware can serve either goal, but the design pressures differ: restorative use foregrounds the timing and contingency of paired feedback, plasticity dosing, and durable outcomes, whereas assistive use foregrounds decode accuracy, bandwidth, and reliability.

The two are not mutually exclusive and increasingly blend: an assistive neuroprosthesis can induce reorganization as a side effect, and a device may be used restoratively early, then assistively if recovery plateaus. Being explicit about which goal a study tests is essential for honest evaluation, because an assistive win (good control) and a restorative win (recovery that transfers off-device) demand different endpoints and controls.