If a patient has a stroke involving the basilar artery, what clinical sign is expected?

A stroke involving the basilar artery can lead to a number of neurological deficits due to its role in supplying blood to critical structures in the brainstem and posterior cerebral circulation. Diplopia, or double vision, is a common clinical sign associated with lesions in this area because of the involvement of cranial nerves that control eye movements, particularly cranial nerves III, IV, and VI.

In the case of a basilar artery stroke, damage to brainstem nuclei can disrupt the coordination of eye muscles, resulting in paralysis of the muscles controlling eye movement. This manifests as diplopia, which can significantly impact a patient's visual perception and balance.

While quadriplegia, apraxia, and global aphasia can occur in different contexts involving strokes, they are not as directly associated with pure basilar artery occlusion as diplopia is. Quadriplegia is typically seen with extensive upper motor neuron lesions affecting the corticospinal tract, which may involve larger areas than just the basilar artery territory. Apraxia is a disorder of motor planning potentially stemming from lesions in the parietal or frontal lobes, while global aphasia is linked to damage in areas responsible for language, typically involving the middle cerebral artery territory rather than the posterior circulation.