Akinetic mutism with bithalamic infarction. Neurophysiological correlates.

A 42-year-old man presented with akinetic mutism, caused by bilateral thalamic infarction, resulting in a temporary amnesic syndrome and, finally, selective downgaze palsy. Electroencephalographic recording in the initial phase showed generalized spike- and-wave discharges, similar to those found in animal studies after lesion or stimulation of specific thalamic nuclei. Analysis of magnetic resonance images (MRI) of the head showed that the centre of ischemic necrosis particularly involved the intralaminar thalamic nuclei and a small part of the rostral mesencephalon. The findings support the previously suggested involvement of cortico-thalamo-mesencephalic circuitry in the initiation of motor responses, and the association of the non-specific thalamic nuclei with the appearance of generalized epileptiform phenomena in cases of reduced vigilance.