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 their body except for vertical eye movements and blinking.

[12] Locked-in syndrome may mimic loss of consciousness in patients, or, in the case that respiratory control is lost, may even resemble death.

People are also unable to actuate standard motor responses such as withdrawal from pain; as a result, testing often requires making requests of the patient such as blinking or vertical eye movement.

Additionally, an EEG can allow the observation of sleep-wake patterns indicating that the patient is not unconscious but simply unable to move.

[14] Assistive computer interface technologies such as Dasher, combined with eye tracking, may be used to help people with LIS communicate with their environment.

However, some people with the condition continue to live for extended periods of time,[15][16] while in exceptional cases, like that of Kerry Pink,[17] Gareth Shepherd,[18][failed verification – see discussion] Jacob Haendel,[19] Kate Allatt,[20] and Jessica Wegbrans,[21] a near-full recovery may be achieved with intensive physical therapy.

Injuries to the pons are the most common cause of locked-in syndrome,Harrison’s principles of internal medicine 21st edition vol 2 page 3332.