Rapid Triage of Auditory Peripheral and Central Phenotypes Using a Brief but Rich Diagnostic Battery
Abstract
Hearing tests are an important part of assessing a person s health, whether they are Service Members being treated after noise damage, Veterans having difficulties with conversations, or civilians. Hearing problems are associated with communicative, social, and cognitive difficulties. Despite the utility of current hearing tests, they have three connected problems. First, they are too simple and only provide information about significant losses in hearing sensitivity. Second, the testing focus on hearing sensitivity largely ignores any damage or compensation in brain regions that are responsible for making sense of sounds. Third, although current protocols could enable more complex evaluations, those evaluations would take too long to be useful. Our proposal aims to create a rich assessment of hearing, and the brain regions involved in hearing, in as short a time as possible. There can be multiple underlying causes of hearing difficulties in clinical populations, depending on an individual s genetics and history of noise exposure. Animal models, in contrast, offer a way to clearly dissociate and individually control these causes. In this study, we propose to design and refine our rapid hearing assessment battery in animal models where underlying causes can be explicitly confirmed. Damage to the early neural regions of the hearing system will be induced in the animal model by overexposure to repetitive noise resembling gunfire. Damage to the brain will be induced by injections of a chemical called D-galactose, which causes the production of molecules damaging to cells (oxidative stress). We will then obtain neural responses to a test battery designed to emphasize the early and later neural pathways of the brain. We then propose to apply this test battery in a population of patients with hearing difficulties that cannot be currently diagnosed by any known tests. By using this translational approach, we aim to arrive at the optimal test battery, which can provide the most information within the least amount of time. Our measurements of neural activities will be supplemented by measuring the extent to which the hearing organ, the cochlea, is damaged, and whether its connections to the rest of the brain are damaged, which is called cochlear synaptopathy or hidden hearing loss. We expect the successful completion of the experiments in this proposal to result in a rapid test battery that can classify, with confidence, the contributions of the different brain regions to a person s hearing difficulties in the absence of any abnormal results using current clinical tests. By concentrating on tests that are modified from existing, mobile, clinical tests (such as the newborn hearing screening test), we can enable rapid translation to the field with minimal concerns about safety and regulatory clearances. We expect this test battery to help monitor hearing damage in active service personnel, inform deployment decisions, and create a new way to objectively diagnose hearing difficulties in Veterans and the general American public.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Dec 05, 2021
- Source ID
- W81XWH2110602
Entities
People
- Edward Bartlett
Organizations
- Purdue University
- United States Army