Preclinical detection of initial vestibulocochlear abnormalities in a patient with multiple sclerosis.

A 49-year-old woman presented with a third-degree continuous spontaneous nystagmus to the left which was followed by a sudden, almost complete deafness of her left ear. These symptoms were established as the sole initial presenting manifestations of multiple sclerosis (MS). Magnetic resonance imaging demonstrated a lesion within the left eight nerve root-entry zone and multiple small central lesions beneath the lateral ventricles. Pure-tone audiometry returned to normalcy after 2 weeks and speech discrimination was 100% after 10 weeks. Auditory brainstem responses (ABRs) showed abnormal parameters during a 10-month follow-up period after the acute hearing loss. Furthermore, desynchronization in ABR testing could be demonstrated 2 days before onset of hearing loss, which was interpreted as a prodromal ABR sign of the incipient MS attack.