A 45 year-old woman with mitral valve disease developed bilateral thalamic infarcts presenting as vigilance disorders, with mutism and downwards gaze paralysis during several days, followed by involuntary rhythmic movements over 13 days. These movements affected the four limbs with a rhythm variable with time as alternate or synchronized agonist-antagonist periods. Subsequent examinations demonstrated global, lasting amnesia and a subclinical disorder of vertical ocular movements. Repeat CT scan confirmed the presence of bilateral anterior thalamic infarcts affecting polar and/or paramedian territories. Emphasis is placed on the similarity of the abnormal movements in this case with L-dopa induced involuntary movements.