Locked in syndrome (LIS) is a condition that can occur as a result of a stroke involving the brainstem; the stroke damages the ventral brainstem, corresponding to the pyramidal bundles.
The infarct is pontine; the midbrain is preserved. The oculomotor nerve III is intact so the patient can open his/her eyes and vertical eye movements are preserved. The patient is conscious with preserved cognitive function but can not move or communicate to the complete paralysis of all voluntary muscles of the body. The patient is a high quadriplegic, impairment of corticobulbar tracts leads to paralysis of VII and VI. There is usually preservation of eyelid elevation and upward gaze. Respiratory insufficiency requires the use of mechanical ventilation.
The most common cause of brainstem stroke is a thrombosis of the basilar artery. Other causes include but trauma or cardiocircolatory failure.
Non contrast CT may show hypodensity of the ventral portion of the pons.
CT angiography allows to evaluate the cerebral vessels and in particular to look for a defect of enhancement of the basilar artery.
For the radiologist the practical application is in part to assume that, until proven otherwise, all patients in ICU are aware of you, what you say and their surroundings until proven otherwise.
The syndrome is well demonstrated in the movie the Diving Bell and the Butterfly. Directed by Julian Schnabel its a sympathetic and moving look at the syndrome and how it affected the life of one man. Well worth watching especially for physicians as it shows the life of the person with the syndrome in a way we would not normally see.
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- 4- León-Carrión J, van Eeckhout P, Domínguez-Morales Mdel R et-al. The locked-in syndrome: a syndrome looking for a therapy. Brain Inj. 2002;16 (7): 571-82. doi:10.1080/02699050110119781 - Pubmed citation