Thomas J. Brozoski, PhD
Division of Otolaryngology - Head and Neck Surgery
Dr. Brozoski is a Research Professor in the Division of Otolaryngology. He received his doctorate in psychology from the University of Virginia studying sensory physiology and completed a post-doctoral fellowship in pharmacology at the University of Michigan. He was a post-doctoral fellow in the Laboratory of Neuropsychology at the National Institute of Mental Health investigating dopaminergic mechanisms of cognition and memory. He came to SIU in 1997 after retiring as the chairman of the Psychology Department at Grinnell College. At SIU he has investigated the neural mechanisms of tinnitus with the goal of translating basic science knowledge into effective strategies for tinnitus treatment.
I. Basic science research.
Our primary research effort since 1993 has been to understand the mechanisms responsible for the perception of chronic tinnitus. An initial step was development of a sensitive and reliable animal model. Chronic tinnitus is induced using noise exposure or ototoxic cochlear damage. The model, which employs a behavioral assay, has been successfully used for two decades in rats and chinchillas, allowing detailed examination of both central and peripheral aspects of tinnitus pathology. Two keys features of the model are its capacity to distinguish the effects of hearing loss from those of tinnitus, and its undiminished sensitivity extending over many months of testing. Using this model we have begun to define the neuroscience of tinnitus and have screened drugs as potential tinnitus therapeutics.
In our basic science research we have used a variety of convergent methods, including very high-resolution functional imaging (manganese enhanced magnetic resonance imaging, MEMRI), single-unit electrophysiology, surgical ablation, pharmacological treatment (both systemic and local microinjection) and point-resolved proton magnetic resonance spectroscopy (1H-MRS). We have collaborated with other laboratories in the Hearing Research Group at SIU and at the Beckman Institute for Advanced Science and Technology at the University of Illinois – Urban Champaign. Our plans are to continue to investigate the potential role of the cerebellum as a critical non-auditory area involved in maintenance of chronic tinnitus. Recently we reported that a unique glutamatergic interneuron that densely innervates the dorsal cochlear nucleus and the vestibulo-cerebellum, the unipolar brush cell, displays a compensatory upregulation in animals with tinnitus and tinnitus with hyperacusis. Our hope is to understand this novel cellular substrate, and that this understanding will ultimately translate into more effective tinnitus management.
Our basic science research has been supported by the National Institute on Deafness and Other Hearing Disorders, the Office of Naval Research, the American Academy of Otolaryngology Head and Neck Surgery and the American Tinnitus Association.
II. Investigator initiated clinical trials.
Our goal is to translate our basic science knowledge, whenever possible, into clinically relevant investigations. Using random controlled trials, we have investigated the therapeutic efficacy of drugs (gabapentin) and acoustic retraining therapies on chronic tinnitus. For this purpose we developed our own computer-driven tinnitus assessment system (TAP) for quantifying both subjective and objective features of tinnitus. TAP has been shared with other laboratories across the country, who have applied it in their own tinnitus research programs. Our clinical trial work has been funded by the Tinnitus Research Consortium.
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