Human temporal bone studies have contributed significantly to our understanding of the pathophysiology of hearing and balance disorders. However, despite previous efforts to elucidate the underlying mechanisms of involved in the pathogenesis of temporal bone disorders, there is a tremendous need to create and study temporal bone specimens from patients with well-defined clincial auditory and vestibular disorders who have undergone quantitative auditory and vestibular function testing, and examination by experienced neurotologists. We propose that the advancement of temporal bone science to elucidate the molecular and cellular pathophysiology behind audiovestibular diseases requires a systematic, prospective clinicopathological correlative approach, coupled with rapid fixation and tissue-processing protocols aimed at antigenic and morphological preservation, and the application of the most modern accurate and reliable methodology for quantification and identification of pathological changes in protein and mRNA gene expression. To accomplish this, we propose in aim 1 to expand the National Temporal Bone Hearing and Balance Resource Registry by recruiting donors and obtaining detailed clinical histories and testing on all those pledging temporal bones, in aim 2 to further develop novel human temporal bone processing techniques to maximize morphologic and antigenic and nucleic acie preservation, in aim 3 to apply the modern techniques of immunohistochemistry, unbiased stereology, in situ hybridization and extraction of RNA on microdissected human temporal bone specimens. Additionally, traditional histopathological correlations will be made. DNA will be analyzed for susceptibility genes and correlations between DMA and RNA expression. In aim 4, we plan to train clinician-scientists and postdoctoral students in temporal bone science and neurotology. In aim 5, we plan to systematically categorize and digitalize images to allow data sharing, and plan to cooperate fully with the Temporal Bone Research Consortium and to collaborate with other temporal bone research laboratories. We will collaborate with Dr. Kumar Alagramam in the development of RNA extraction using laser capture microdissection, and with Dr. Allen Ryan in the application of in situ hybridization on formalin-fixed paraffin-embedded sections.