The correct answer
The correct answer is A. This patient presents with a phenomenon known as "locked-in" syndrome. Unlike a persistent vegetative state, which is characterized by a loss of awareness and cognitive function, patients with locked-in syndrome are completely awake and cognitively intact with no abnormality of consciousness. However, they are unable to move the extremities and most of the face, and are often limited to communication by vertical eye movements or blinks. The disease results most commonly from large lesions in the brain stem, particularly at the base of the Pons, such as those produced by a thrombotic stroke to the basilar artery.
Occlusion of an internal carotid artery (choice B) is unlikely to present in the manner described because collateral circulation from the other internal carotid artery should compensate for the unilaterally reduced perfusion.
Middle cerebral artery strokes (choice C) usually present with lateralizing symptoms, such as a gaze deviation or hemiparesis. Since the parietal cortex is primarily perfused by this artery, symptoms involving parietal lobe dysfunction such as agnosias, apraxias, hemi-neglect, and language and calculation problems are more likely to occur.
The posterior cerebral artery (choice D) supplies the occipital lobe as well as the medial portions of the parietal and temporal cortex. Symptoms will usually be lateralizing, and visual changes are almost certainly present.
Occlusion of the superior cerebellar artery (choice E) would more likely present with ataxia and dysarthria than with the severe symptoms described in this patient.
A lesion of the ventral pons can result in "locked-in" syndrome, in which the patient develops quadriplegia and inability to speak but is aware, is awake, and can communicate by vertical eye movements or blinks. Branches of the basilar artery supply the ventral pons