Vestibular compensation in a patient with a cerebellar infarction.

We report the case of a 67-year-old man who suffered a traumatic unilateral peripheral vestibular injury subsequent to an unrelated prior cerebellar infarction that occurred at least 2 years earlier. The patient's clinical course was marked by poor compensation for his peripheral vestibular loss. Four months after his vestibular injury, his symptoms of dizziness had not resolved. He had a spontaneous vestibular nystagmus, and laboratory testing indicated an asymmetric semicircular canal-ocular reflex. The otolith-ocular reflex, tested using off-vertical axis rotation, also was asymmetric but had a preserved modulation component. Visual-vestibular interaction and semicircular canal-otolith interaction were normal. An MRI indicated preservation of the flocculo-nodular lobe but infarction of the pyramis and uvula. Taken together, the findings in this case suggest that despite structural and functional preservation of the flocculo-nodular lobe, an anatomic region often labeled the "vestibulo-cerebellum", a lesion of the cerebellum that can impair CNS compensation for a unilateral peripheral lesion in humans.