Measurements of Cochlear Synaptopathy Using Electrocochleography
Abstract
Cochlear synaptopathy is a condition where hair cell function remains viable even though synaptic connection with the auditory nerve has been severed. As a means to test for the presence of this condition, it has long been recognized that electrocochleography (ECochG) provides an unparalleled and highly informative window into cochlear function. Experiments in animals using ototoxins and neurotoxins have allowed us to identify unique signatures of responses from hair cells and the auditory nerve, respectively. These have allowed us to identify unique metrics that are associated with synaptopathy. The goal of this project is to develop an innovative approach to use ECochG to serve as the centerpiece of a battery of differential tests focused on cochlear synaptopathy and its perceptual sequelae. This objective aligns itself precisely with the FY18 HRRP FARA Focus Area that calls for the development of methods to assess auditory dysfunction related to synaptopathy and hidden hearing loss. The plan is to develop ECochG measures that provide a detailed picture of the functional properties of an individual's hair cells and neural elements, and to relate this cochlear profile to auditory performance. The study includes both animal and human studies. The animal studies are ongoing and the human studies to date are based on analyses of existing data with approval for new studies pending. Animal results with neurotoxins and human studies in subjects with various degrees of hearing loss are showing effects of synaptopathy on ECochG potentials and models developed to analyze the results are producing reliable metrics of its presence. Development of an animal model of synaptopathy with noise exposure is under active development in terms of response magnitudes, measures of indices of synaptopathy, measures of distortion products, and anatomical counts of immunolabeled synapses.
Document Details
- Document Type
- Technical Report
- Publication Date
- Sep 01, 2020
- Accession Number
- AD1117095
Entities
People
- Douglas C Fitzpatrick
Organizations
- University of North Carolina at Chapel Hill