A Case Suspected of Bilateral Progressive Retrocochlear Deafness

Abstract

A 17-year-old girl complained of bilateral progressive deafness since age of ten. She could hear sound but could not understand speech. Pure tone audiometry showed that her hearing was fluctuating within a range of 40dB in both sides, and pure tone average was 68-86dB in the right ear, and 56-65dB in the left ear. In speech audiometry, maximum articulation score was 0% in both sides Békésy audiometry indicated type IV pattern, which seemed to be pathognomonic to a retrocochlear lesion. Reflex decay in acoustic-stapedial reflex test was positive. Audiotory brainstem response and action potential in electrocochleogram were not evoked even at the maximum stimulation level of 70dB HL. On basis of these findings, her hearing loss was suspected as of brain stem lesion due to unknown pathology.