THE DISCONNECTED EAR - PHENOMENOLOGICAL EFFECTS OF A LARGE ACOUSTIC TUMOR

Objective: To document the existence of a peripheral auditory disconne ction syndrome in a 23-yr-old male with a large tumor of the right cer ebellopontine angle using contemporary behavioral, electroacoustic, an d electrophysiologic auditory tests. Design: Single subject with repea ted measures. Results: In spite of a profound hearing loss in an ear w ith a large cerebellopontine angle tumor determined by behavioral audi ometry, distortion product otoacoustic emissions, surface recorded bra in stem auditory evoked potentials, and transtympanic electrocochleogr aphy (click evoked compound action potentials and tone evoked cochlear microphonics) demonstrated that the cochlea was intact and functional over a broad bandwidth and intensity range. Conclusions: A peripheral auditory disconnection syndrome is demonstrated in a 23-yr-old male w ith a large tumor of the cerebellopontine angle. In this instance, the tumor effectively deafferentated the peripheral from central auditory nervous system, resulting in profound hearing loss of presumed neural origin. It is suggested that other pathologic conditions/mechanisms c ould produce similar findings.