Hypoplastic Cochlear Nerve
ES, a 9-month-old, was referred by her pediatrician because of parental concerns regarding her hearing. Pre-, peri-, and post-natal history was unremarkable. ES passed her newborn otoacoustic emissions hearing screening bilaterally. Two behavioral hearing tests by another audiologist revealed inconsistent responses to sound utilizing visual reinforcement audiometry (VRA), normal tympanic membrane motility, and present distortion-product otoacoustic emissions (DPOAEs).
ES was re-evaluated at 13 months of age using bone conduction to condition to VRA (▶ Fig. 1). Test results revealed no response at the limits of the audiometer in the sound field, and responses with bone conduction at vibrotactile levels. Robust DPOAEs were present bilaterally (▶ Fig. 2). An auditory brainstem response (ABR) under sedation was recommended.