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Approximately 30 million Americans suffer from varying degrees of hearing loss. Hearing loss affects individuals of all ages and is one of the most common conditions affecting older adults. Individuals with profound hearing loss are considered deaf. In the majority of cases hearing loss is due to abnormal development or injury to sensory cells harbored in the hearing organ within the inner ear called cochlea. Highly complex in function, cochlea is nevertheless highly ordered in morphology. Rows of sensory ‘hair' cells are studded in an orderly fashion within the spiral ‘staircase' of the cochlear duct. The hallmark of the sensory cell is a tuft of hair-like projections on the apical surface of the cell, hence the name ‘hair cell'. These hair cells are exquisite sensors with great adaptability that enable the subject to respond to a whisper, enjoy a concert or hear a child talk in a crowd. Genetic predisposition, age, noise, ototoxic drug or a combination of these factors can affect hair cells resulting in hearing loss. The hearing loss is permanent in many cases because affected hair cells degenerate and are not replaced. Other priority areas in the hearing research field where in-depth analysis at the basic level could lead to better understanding of the cause & course of disease are otitis media and Meniere's disease. Otitis media is an infection or inflammation of the middle ear. It is estimated that medical costs and lost wages because of otitis media amount to $5 billion a year in the U.S. Although otitis media is primarily a disease of infants and young children, it can also affect adults. Ménière's disease is a significant problem that affects adult population. Ménière's disease is a disorder of the inner ear that affects hearing and balance. It causes sudden attacks of vertigo (a spinning sensation), tinnitus (a loud ringing in the ears), and a loss of hearing. Otitis media is a $5 billion problem in the U.S. and it predominantly affects children.
Impetus for the HRP at Case comes from our encouraging success in recent years. Reports from our lab provided first genetic evidence that mutation in a protocadherin gene (Pcdh15) causes deafness in mouse (January 2001). A few months later, in collaboration with Dr. Smith's lab in the University of Iowa , we showed that mutation in the human Pcdh15 gene is the cause of deafness in patients diagnosed with Usher syndrome type 1F. The initial work that led to the identification of Usher 1F gene was made possible by using mouse models and the tools of basic science research.
The ultimate aim of HRP at Case School of Medicine is to make fundamental contributions to the effort aimed at defeating deafness and protecting against hearing loss. To this end, it will be necessary to understand the genetic program underlying development, protection and possible regeneration of hair cells. We are interested in identifying genes associated with development, protection and regeneration of hair cells in the laboratory mouse. The laboratory mouse has proved to be an excellent model for hearing research. Basic science research will not only help us understand how hearing happens but it will also be necessary to unravel pathogenic changes causing hearing loss and to identify plausible therapeutic targets to prevent/preserve hearing function.
Research in the HRP focuses on high priority areas in the field. Various animal models are utilized to understand both normal and impaired auditory system. Investigators from various departments in the School of Medicine and School of Engineering are involved in research projects associated with the HRP and we has established collaborations with experts in the field, both nationally and internationally.
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