Bilateral paramedian thalamo-midbrain infarction showing electroencephalographic alpha activity

A 57-year-old man became unresponsive and mute with bilateral ophthalmopleg ia and quadriplegia. Magnetic resonance imaging (MRI) showed bilateral infa rctions at the ventral midbrain and the dorsomedial nucleus of the thalamus . Serial studies with MR and vertebral angiography disclosed hypoperfusion and spontaneous reperfusion of the bilateral posterior cerebral arteries at their origin from the basilar artery. Electroencephalographically, a poste riorly distributed alpha rhythm was clearly recorded and it was reactive in response to external stimuli. The findings seen in the present patient sug gest that the ventral midbrain and medial dorsal thalamus are not necessary to produce posterior electroencephalographic alpha activity.