Neuromyelitis optica spectrum disorder with deafness and an extensive brainstem lesion.

A 49-year-old woman developed vomiting, hiccups, double vision, and bilateral ptosis, after which tinnitus and deafness appeared. Head magnetic resonance imaging (MRI) showed a brainstem lesion focused on the midbrain and pons. Anti-aquaporin 4 (AQP4) antibody was positive, and there was no evidence of optic neuritis or myelitis, leading to the diagnosis of neuromyelitis optica spectrum disorder (NMOSD). The auditory brainstem response (ABR) showed no derivation of wave V on left stimulation and extended latency between waves III and V on right stimulation, so impairment between the midbrain and pons was suspected. It was useful to evaluate head MRI and the ABR for identification of the location of auditory pathway dysfunction.