ARRA Investments in Tinnitus
Public Health Burden
Tinnitus is a major health concern that affects approximately 25 million Americans. Individuals with tinnitus experience a ringing, roaring, or buzzing sound in the ears or head. The condition can range in severity from a mild condition which requires no intervention to a severe debilitating disease with significant emotional, social, and economic impact. It has been reported that many U.S. military personnel returning from active duty experience noise-induced hearing loss and tinnitus.
Tinnitus is a symptom associated with many forms of hearing loss; however a significant obstacle for advancement in this field is a lack of knowledge about the specific neural dysfunction(s) responsible for tinnitus. Understanding the basic biology underlying tinnitus will aid in more accurate diagnosis of affected individuals. The ARRA Challenge Grant program has allowed significant expansion of research in this important area.
One Challenge Grant project will directly record patterns of activity in the brain of animals with or without noise-induced tinnitus. The goal of this work is to identify abnormal brain activity correlated with tinnitus following acoustic trauma.
Another Challenge Grant project will utilize advanced functional MRI technology to identify differences in brain activity and volume in individuals with hearing loss that do or do not experience tinnitus. The researchers aim to identify new brain regions to target for intervention.
A final tinnitus Challenge Grant project will explore the coupling of activity between brain centers, such as those processing sound and emotions, in individuals with and without tinnitus. This work may fundamentally change how the field conceptualizes the brain mechanisms underlying tinnitus.
Many researchers hypothesize that tinnitus may result from inappropriate activity of certain brain regions after loss of input from the sensory hair cells of the inner ear, similar to phantom limb sensations. While basic researchers seek to understand the molecular and structural brain changes, other researchers are examining how drugs either contribute to or alleviate the tinnitus percept.
One project will identify how a class of ototoxic drugs, aminoglycosides, enter the cochlea, and their subsequent trafficking to sensitive sensory hair cells. This research will enable the development of new strategies to prevent hair cell damage and loss due to aminoglycosides. ARRA funding allowed the hiring of a new research assistant and retention of a post-doctoral fellow, thereby accelerating the project’s completion.
Electrophysiological recordings from animals experiencing tinnitus will provide a better understanding of neuronal mechanisms which underpin tinnitus development in central auditory structures. ARRA investments are supporting the purchase of new electrophysiologic equipment, allowing brain activity recordings in a behavioral setting and providing a model for testing anti-tinnitus drugs.
Another project examines neurophysiological and brain imaging correlates to determine if tinnitus is suppressed by a potassium channel modulator. ARRA investments are supporting the purchase of data acquisition hardware and a behavioral testing environment, allowing researchers to accelerate completion of the project.
Brain Stimulation Therapies
Another tinnitus treatment strategy being explored is the use of brain stimulation. These therapies may be invasive or non-invasive and directed either to peripheral or central nervous system structures.
One ongoing research project studies the brain function of people with tinnitus and the impact of magnetic stimulation to the brain. The results of this research will help explain why some people experience tinnitus and if magnetic stimulation is helpful. An ARRA supplement hired a new senior research technician to perform advanced magnetic imaging and analysis that will accelerate understanding of tinnitus and the use of magnetic stimulation as an effective treatment.
Recently, cochlear implants have been demonstrated to alleviate tinnitus in some individuals. An ongoing research project is exploring the interaction between acoustic (normal) and electric (implant) hearing. An ARRA supplement supported the creation of a new job for a recently unemployed, highly-skilled professional. The industrial experience and expertise added will accelerate the pace of translating basic research into clinical practice.
Finally, a research project is exploring tinnitus and tinnitus suppression through direct electrical stimulation of the brain by an implanted electrode array. The additional equipment supported by ARRA investments will allow more precise implantation of the electrode array and improve the data acquisition and processing from the implant.
-- Understanding the Neural Mechanisms Responsible for Tinnitus -- Young, Eric Daniel (MD)
-- Brain Changes in Tinnitus -- Rauschecker, Josef P (DC)
-- Networking of Brain Activity in People with Tinnitus -- Melcher, Jennifer Renee (MA)
-- Hair Cell Response to Ototoxic Drugs -- Steyger, Peter S (OR)
-- The Glycine Receptor in a Rat Tinnitus Model: A Possible Therapeutic Target -- Caspary, Donald Michel (IL)
-- Animal Models of Tinnitus, Brain Imaging & Therapy -- Salvi, Richard J (NY)
-- Collaborative Tinnitus Research at Washington University -- Piccirillo, Jay F (MO)
-- Interactions Between Acoustic and Electrical Stimulation -- Zeng, Fan-Gang (CA)
-- Cortical Electrical Suppression of Noise-Induced Tinnitus -- Zhang, Jinsheng (MI)
Page Last Updated on June 30, 2018
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