Locked-in syndrome

Locked-in syndrome, also known as pseudocoma, is a rare neurological condition in which a person is fully conscious and cognitively intact but cannot move or speak due to near-total paralysis of the voluntary muscles throughout the body, sparing only vertical eye movement and blinking. It results from damage to the brainstem that produces quadriplegia and bulbar palsy while leaving the brain's higher functions untouched; affected people retain normal sleep-wake cycles and attention, confirmed by normal electroencephalography readings, and can often communicate through eye movement alone. The condition and its name were described by the neurologists Fred Plum and Jerome B. Posner, who coined the term in 1966.