A 65-year-old patient presents with 'top of the basilar' syndrome. Which cluster of deficits is most characteristic?

• A Altered consciousness, visual disturbances (cortical blindness, oculomotor palsy), behavioral changes, and memory impairment ✓
• B Contralateral hemiplegia with ipsilateral third nerve palsy (Weber's syndrome)
• C Locked-in syndrome with preserved vertical eye movements
• D Ipsilateral limb ataxia with contralateral body hemianesthesia

Explanation

Top of the basilar syndrome results from occlusion of the rostral basilar artery affecting the midbrain, thalamus, and occipital and medial temporal lobes. It produces a constellation of: altered consciousness (thalamic infarction), oculomotor palsies (CN III fascicles, vertical gaze center in rostral midbrain), cortical blindness or visual hallucinations (PCA territory occipital infarct), memory impairment (medial temporal/hippocampal infarct), and behavioral changes. Weber's syndrome (option B) is a unilateral midbrain lesion. Locked-in syndrome (option C) is a bilateral pontine basis infarct.

Reference: BD Chaurasia's Human Anatomy, 8th ed.

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Written and medically reviewed by the StethoPrep medical team.