Auditory Nerve Disease of Both Ears Revealed by Auditory Brainstem Responses, Electrocochleography and Otoacoustic Emissions

We report on two patients who showed absence of auditory brainstem response (ABR) but broad compound action potentials on electrocochleograms and almost normal otoacoustic emissions, together with absence of caloric response and preservation of per rotatory nystagmus for both ears. Patient 1, a 53-year-old woman, had noted auditory and vestibular problems since the age of 15 years, and Patient 2, a 68-year-old woman, had noted problems of the same age of 30 years. They could hear words and understand sentences if spoken slowly, but they could not discriminate monosyllables very well. Their auditory examinations disclosed mild threshold elevation in pure-tone audiometry and markedly poor scores in speech audiometry and good scores in auditory comprehension test. They were diagnosed as having auditory nerve disease of unknown cause.