Locked-in syndrome

Locked-in syndrome
CerebellumArteries.svg
Locked-in syndrome can be caused by a stroke at the level of the basilar artery denying blood to the pons, among other causes.
Synonyms	Cerebromedullospinal disconnection, ventral pontine syndrome
Specialty	Neurology, Psychiatry

Locked-in syndrome (LIS), also known colloquially as pseudocoma, is a neurological condition characterized by complete paralysis of nearly all voluntary muscles except for those controlling vertical eye movements and blinking. Despite this physical immobility, individuals with LIS remain conscious and cognitively intact, capable of communication via controlled eye movements. Electroencephalography (EEG) results typically appear normal in LIS patients. An even more severe form, termed total locked-in syndrome or completely locked-in state (CLIS), includes paralysis of the eye muscles. The term was first proposed by Fred Plum and Jerome Posner in 1966.

Signs and Symptoms

In locked-in syndrome, individuals are fully conscious and aware but unable to move or speak due to near-complete paralysis of voluntary muscles. The most commonly preserved voluntary control is over eye movement and blinking, allowing individuals to communicate.

Causes

Locked-in syndrome typically results from damage to specific portions of the lower brain and brainstem, without affecting the upper brain. Most commonly, it is caused by a stroke or lesions affecting the pons, a part of the brainstem that contains nerve fibers responsible for motor control.

Diagnosis

Diagnosis of locked-in syndrome involves clinical evaluation, neuroimaging, and electrophysiological studies. It is important to distinguish LIS from other conditions with similar presentations such as coma, vegetative state, or pseudocoma.

Treatment

There is currently no cure for locked-in syndrome. Treatment primarily focuses on supportive care, rehabilitative therapies, and methods to improve communication. Advanced technologies, such as eye-tracking devices and specialized computer software, can significantly enhance the ability of LIS individuals to interact with their environment.

Prognosis

The prognosis for individuals with locked-in syndrome can vary significantly. While it is generally considered a stable condition, with proper medical care, individuals can potentially live for several decades. Quality of life can be greatly improved with access to adaptive equipment and supportive care.

Research

Research into locked-in syndrome is ongoing, with efforts focused on deepening our understanding of the condition and exploring potential therapeutic interventions. Studies encompass a wide range of fields, from basic neuroscience to advanced assistive technology.

• 
•