Locked-in syndrome: A neurological disorder characterized by complete paralysis of voluntary muscles in all parts of the body except for those that control eye movement. The locked-in syndrome is usually a complication of a cerebrovascular accident (a stroke) in the base of the pons in the brainstem. The patient is alert and fully conscious but cannot move. Only vertical movements of the eyes and blinking are possible.
Locked-in syndrome can also be due to traumatic brain injury, demyelinating diseases (disorders in which the insulating material around brain cells is lost), and medication overdose.
There is no cure for locked-in syndrome, nor is there a standard course of treatment. Functional neuromuscular stimulation may help activate some paralyzed muscles. Several devices to help communication are available. Other treatment is symptomatic and supportive. The prognosis for those with locked-in syndrome is poor. The majority of patients do not regain function.