Locked-in syndrome.

The prerequisites for the locked-in stste are the presence of two components: one negative-sufficient paralysis of structures that render usual communications (mouth and oral apparatus for speech, and limbs for writing and pointing accurately) and one positive- preservation of consciousness. Lesions of the pontine base cause the syndrome. The most common pontine lesions are infarction related to basilar artery occlusion and pontine hemorrhages. Occasionally midbrain vascular lesions can cause the syndrome.