[A case of infarction in brainstem and cerebellum as a initial symptom with bilateral hearing loss]

A 56-year old male presented with a sudden onset of bilateral hearing difficulty. He complained of dizziness and gait disturbance at the onset and subsequently developed bilateral hearing loss and tinnitus. Brain MRI revealed multiple infarcts in bilateral middle cerebellar peduncles, bilateral cerebellar hemispheres and the right cerebral peduncle. Three dimentional computed tomography angiography (3D-CTA) showed severe stenosis of bilateral vertebral arteries. Infarcts were located in the border zone between anterior inferior cerebellar artery (AICA) and superior cerebellar artery (SCA), suggesting hemodynamic infarctions. Auditory brain stem responses (ABR) were recorded three times. The initial ABR demonstrated all waves except for wave I on day 14. Wave I on the left was normal, while wave I peak latency on the right was prolonged. On day 61, all waves were recorded, although peak latencies of waves III to V and interpeak intervals of the wave I to III on the right side were prolonged. Involvements of the cochlear nerve and pontine auditory pathway were suggested from the ABR abnormalities in this case.