Cochlear Implants: Evolving Perspectives

2. Genetic Research, Bioethical Issues, and Cochlear Implants: An Overview of the Issues Affecting the Deaf Community

20 2 GEnEtIC REsEaRCh, BIoEthICaL IssUEs, anD CoChLEaR ImPLants: an ovERvIEW of thE IssUEs affECtInG thE DEaf CommUnIty Jane Dillehay Not everything that is faced can be changed, but nothing can be changed until it is faced. —James Baldwin The Deaf community has always had flexibility and foresight in adapting to innovative developments in technology. The products of researchers and engineers from hearing aids to telecommunication devices to the Internet and vlogs have been rapidly incorporated into Deaf culture and used to strengthen the Deaf community. As the National Association of the Deaf (NAD) position paper on cochlear implants (2000) states, The NAD recognizes all technological advancements with the potential to foster, enhance, and improve the quality of life of all deaf and hard of hearing persons. During the past three decades, technological developments . . . have had an important role in leveling the playing field. The role of the cochlear implant is evolving and will certainly change in the future. It remains to be seen whether the current and rapidly accelerating advances in genetics research and the steadily increasing frequency of cochlear implantations will improve or jeopardize the future of the Deaf community. ConsequenCes of the human genome ProjeCt A genome is the total sum of DNA, or genetic material, in each cell of an organism . The goal of the Human Genome Project was to understand human genetics by sequencing human DNA to create a map of the approximately 25,000 genes that make up a person. The complete sequencing of the human genome was first achieved in 2003, and the genome information for an ever-increasing number of humans and other species was made available to all researchers through Internet genetIC researCh, BIoethICaL Issues, and CoChLear ImPLants 21 databases. Current research efforts focus on when and how genes are activated to produce the cell machinery necessary for life (U.S. Department of Energy Office of Science, Human Genome Program, 2009). While mapping the genomes of different species continues to be an important endeavor, the next step in understanding how an organism functions is at the level of the proteome, which is the complete set of proteins produced by each cell or organism. Studying the proteome is a far more complex process because the genome is reasonably constant over time but the proteome changes from cell to cell and from conception to maturity to death, depending on gene activities. Therefore deciphering the proteome, including the structure and function of each cell protein and the complex interaction of thousands of proteins within and among cells and tissues, will be the next important step for developing an understanding of normal human physiology and therapeutic strategies for various conditions. In addition to the tremendous increase in genome databases, increasing sophistication in research tools—rapid-sequencing low-cost genomic technology, software analytic algorithms, selective breeding of mouse genetic models—to cite a few examples, have come together to create a synergistic explosion of knowledge with breakthroughs identifying genes for given conditions almost daily. Although some genomic applications for the treatment of genetic conditions have progressed to the stage of human clinical trials, this is not yet the case for genes and proteins that modulate hearing. genetICs of hearIng Loss Estimates of the prevalence of hearing loss in the American population vary widely depending on the survey methodology used. One recent study estimates the prevalence for speech-frequency hearing loss in one or both ears at 29 million Americans and for high-frequency hearing loss at 55 million based on survey data from the National Health and Nutrition Examination Survey 1999–2004 (Agrawal, Platz, & Niparko, 2008). This relatively high incidence of hearing loss in comparison to other disabilities is a motivating factor for providing federal funding for research to understand how hearing works and ultimately to discover therapeutic approaches for people who desire a change in their hearing status. It should be noted that this survey does not distinguish among causes of hearing loss, whether genetic, environmental, or some combination of the two, or age of onset of hearing loss. Nance (2003) notes that hearing loss is an extremely complex condition with multiple known causes, both genetic and environmental, due to the orchestration of the many physical and biochemical interactions required to accomplish the task of hearing, from the mechanical structures of the ear to the conversion of sound to nerve impulses conducted via the auditory nerve to the brain’s auditory complex 22...