Peripheral neural synchrony in pediatric cochlear implant users

Abstract

We recently developed a noninvasive method to quantify neural synchrony in the electrically stimulated cochlear nerve (i.e., peripheral neural synchrony) using an index named the phase locking value (PLV). The PLV is a measurement of trial-to-trial phase coherence in the summated activity of cochlear nerve fibers. Larger PLVs indicate better/stronger peripheral neural synchrony. This tool allows for investigating this important phenomenon in cochlear implant (CI) users for the first time in the literature. The aim of this study was to characterize peripheral neural synchrony in a large group of pediatric CI users with various etiologies. To date, study participants included 17 children with cochlear nerve deficiency, 28 children with Gap Junction Beta-2 mutation, nine children with normal inner ear anatomy and idiopathic hearing loss, three children with enlarged vestibular aqueducts, three children with Mondini malformation and two children with Usher syndrome. All participants use Cochlear™ Nucleus® devices in their test ears. For each implanted ear tested in each participant, peripheral neural synchrony was assessed at the maximum comfortable level and multiple electrode locations across the electrode array. Our preliminary results demonstrated substantial variations in peripheral neural synchrony among pediatric CI users. These variations appear to depend on hearing loss etiologies.