Locked-in syndrome

Nicole Reams MD (Dr. Reams of the University of Michigan has no relevant financial relationships to disclose.)
Matthew Lorincz MD PhD, editor. (Dr. Lorincz of the University of Michigan receives salary support from Wilson Therapeutics AB for performing UWDRS examinations in a clinical trial.)
Originally released May 19, 2004; last updated January 23, 2015; expires January 23, 2018

This article includes discussion of locked-in syndrome, cerebromedullospinal disconnection, de-efferented state, pseudocoma, disorders of consciousness, classic locked-in syndrome, and complete and incomplete locked-in syndrome. The foregoing terms may include synonyms, similar disorders, variations in usage, and abbreviations.


In the purest sense, locked-in syndrome occurs when a patient becomes "de-efferented" due to a lesion occurring in the brainstem, classically in the ventral pons. Cortical function remains unimpaired, but it leads to quadriplegia and paralysis of lower cranial nerves with retained consciousness. In this article, the author discusses the presentation, etiology, prognosis, diagnostic evaluation, and management of locked-in syndrome. Updates focus on the progress in brain-computer interfaces for communication and functionality of these patients.

Key points


• Locked-in syndrome is a de-efferented state characterized by quadriplegia and paralysis of the lower cranial nerves.


• Patients retain consciousness and can classically communicate by vertical eye movements and eye blinking.


• The most common etiology is atherothrombotic occlusion of the basilar artery resulting in ischemia of the ventral pons.


• Advances in technology, such as brain-computer interfaces, are allowing for improved communication for locked-in syndrome patients.

Historical note and terminology

The first published case of locked-in syndrome in 1947 described a conscious patient with an infarction in the territory of the vertebral-basilar artery system who manifested tetraplegia and no verbal communication, consistent with locked-in syndrome (van Eeckhout 1997). Plum and Posner first introduced the term in 1983, and they described the syndrome as “a state in which selective supranuclear motor de-efferentation produces paralysis of all 4 limbs and the last cranial nerves without interfering with consciousness” (Plum and Posner 1982).

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