Beginner
Locked-in syndrome
Also known as: LIS, Complete locked-in syndrome, CLIS
A condition in which a person is conscious and aware but almost completely paralyzed, often able to communicate only with eye movements, or not at all.
It can result from brainstem stroke or late-stage ALS. In complete locked-in syndrome even eye movement is lost, and BCIs may be the only possible channel for communication.
Last updated Sep 30, 2026. Educational content, not medical advice.