Locked-in syndrome (LIS), also known as pseudocoma, is a condition in which a patient is aware but cannot move or communicate verbally due to complete paralysis of nearly all voluntary muscles in the body except for vertical eye movements and blinking. The individual is conscious and sufficiently intact cognitively to be able to communicate with eye movements. Electroencephalography results are normal in locked-in syndrome.
Total locked-in syndrome, or completely locked-in state (CLIS), is a version of locked-in syndrome wherein the eyes are paralyzed as well. Fred Plum and Jerome B. Posner coined the term for this disorder in 1966.
Signs and symptoms
Locked-in syndrome is usually characterized by quadriplegia (loss of limb function) and the inability to speak in otherwise cognitively intact individuals. Those with locked-in syndrome may be able to communicate with others through coded messages by blinking or moving their eyes, which are often not affected by the paralysis.