LockedIn

Locked-in syndrome, sometimes written as locked-in, or referred to as a locked-in state, is a neurological condition in which a person is fully conscious and aware but cannot move or communicate verbally due to paralysis of nearly all voluntary muscles. Most individuals retain eye movements and blinking, which can be the primary means of interaction. The condition is classically caused by damage to the ventral pons in the brainstem, disrupting motor pathways while leaving sensory pathways and consciousness intact.

Common causes include acute brainstem stroke (often basilar artery infarction or hemorrhage), traumatic brain injury, brainstem tumors, severe infections, demyelinating diseases, or metabolic disorders that injure the brainstem. The onset is typically sudden in stroke cases and can follow degenerative or progressive processes in other circumstances. The syndrome is distinguished from coma and vegetative states by preserved arousal and awareness, evidenced by intact cognitive function and perception.

Symptoms and signs center on paralysis of nearly all voluntary muscles, including those for speech and facial movement, with preserved vertical or limited horizontal eye movements and blinking. Patients may experience difficulty with breathing and autonomic regulation, while sensory perception, pain, and consciousness can remain intact. Communication usually relies on eye movements, blinking, or specialized technology such as eye-tracking devices or brain-computer interfaces.

Diagnosis involves clinical examination and imaging studies, such as MRI or CT scans, to identify brainstem injury. Electroencephalography and neurophysiological testing may support assessment of preserved consciousness. Treatment focuses on addressing the underlying cause, stabilizing the patient, and providing supportive care. Long-term management emphasizes communication support, rehabilitation, nutritional and respiratory care, and psychosocial support. The prognosis varies; most cases with complete pontine injury have limited recovery, though rare partial improvements can occur.

The term locked-in was popularized in the 1960s to describe patients who are fully conscious yet immobilized, a contrast to coma or vegetative states. The concatenated form “lockedin” is less common and not standard usage in medical literature.