Objective: The objective of this study was to outline the possible implications and potentially valuable techniques for managing cases in which the neural integrity of the peripheral auditory system is in question.
Study design: This study was a retrospective case review.
Subject and method: A 3-year-old child with a profound blilateral sensorineural hearing loss was assessed for suitability of cochlear implantation. Audiologic tests confirmed that the child met the audiologic criteria for cochlear implantation. Computed tomographic scanning and magnetic resonance imaging were undertaken.
Results: Computed tomographic scanning showed bilateral narrow internal auditory canals. Magnetic resonance imaging showed the absence of the acousticofacial bundle on the left side and possible atrophy of the bundle on the right. After detailed discussion, the parents elected to proceed with implantation on the right ear using the Nucleus mini-22 cochlear implant. Tuning of the device resulted in myogenic facial activity with no electrically stimulated auditory sensation. Postoperative electrophysiologic testing confirmed the presence of a compound muscle action potential only.
Conclusions: Seven months after implantation, the child was explanted uneventfully. The electrical auditory nerve action potential and the electrically evoked auditory brainstem response, using intracochlear stimulation, are potentially valuable measurements to assess neural integrity before the decision to proceed with implantation is made.