BCI-controlled functional electrical stimulation (BCI-FES)

A rehabilitation loop in which decoded movement intent — commonly motor-imagery sensorimotor-rhythm desynchronization, or higher-resolution cortical signals — triggers functional electrical stimulation of the paretic muscles, so the intended movement is physically produced at the moment it is willed. This couples the top-down volitional command with the resulting proprioceptive and cutaneous afferent volley in a Hebbian, contingent fashion, aiming to reinforce the damaged sensorimotor pathway. It is distinct from open-loop FES, which stimulates on a schedule without regard to the patient's own command.

Honesty: a well-known randomized trial in chronic stroke found that EEG-BCI-triggered FES produced greater and lasting motor improvement than sham (randomly-triggered) FES, with accompanying changes in functional connectivity — evidence that contingency, not just muscle activation, drives the benefit. Effects are meaningful but moderate, are best in patients with residual corticospinal sparing, and the approach remains an emerging adjunct rather than settled care.