The first case, to our knowledge, of bilateral, symmetric and simultaneous infarction in the basal territory of the middle cerebral arteries is reported. The patient presented with a pseudo-rostral brainstem syndrome, including loss of oculo-vestibular reflexes, severe tetraparesia and akinetic mutism-like disturbance of consciousness. The lesions were due to embolism, caused by atrial fibrillation, occluding the ostium of the lenticulostriate arteries. It involved only the putamino-capsulo-caudal regions, concerning the whole anterior and posterior dorsal capsules. The term tetraparetic mutism is proposed to describe this new clinico-pathological syndrome, which is the sum of a capsular tetraparesia, due to the lesion of the geniculate and cortico-spinal fibres at the level of the genu and posterior limbs, and of a capsular akinetic mutism, due to the lesion of the reticular thalamo-cortical tracts at the level of the anterior limbs. These total capsular infarcts moreover involved all the oculomotor cortico-reticular tracts, which could explain the absence of oculo-vestibular reflexes.