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STATEMENT OF DR. JAMES B. SNOW, JR.
It is a privilege to appear before this Committee as the Director of the National Institute on Deafness and Other Communication Disorders (NIDCD). In the past two and a half years since the Institute was created, we have witnessed an increased vigor in the pursuit of answers to questions about the nature of human The NIDCD has supported research and research training on both the normal and disordered functions of hearing, balance, smell, taste, voice, speech and language primarily through investigator-initiated research and by supporting mechanisms of research training designed to encourage scientists to work on the challenging problems confronting this field. The NIDCD continues to monitor its progress through close attention to and scheduled updating of the National Strategic Research Plan and by fostering critically needed basic research to improve our understanding of human communication while supporting research protocols for prevention, therapeutic intervention and development of devices that will improve the quality of life for those who already have communication
One in one thousand infants is born deaf.
Approximately 2 million persons are profoundly deaf. Forty to sixty percent of profound neonatal deafness can be attributed to genetic causes. More than 50 different forms of hereditary deafness are known. The NIDCD has made important progress on two forms of hereditary
deafness, Usher syndrome and Waardenburg syndrome. NIDCD investigators have recently located the Usher type 2 gene on chromosome 1 and have begun to fine map and to clone and characterize the gene. A team of scientists in the NIDCD Intramural Research Program and a network of clinicians are at work studying Waardenburg syndrome. Geneticists, otolaryngologists and audiologists throughout the country have been enlisted to bring together intramural scientists and families with hearing loss due to Waardenburg syndrome who would like to participate in the Initially, the focus will be on the mapping of the gene involved in Waardenburg syndrome. This information can be used subsequently to improve diagnosis and genetic counseling and eventually may lead to gene therapy for syndromes of hereditary deafness.
Basic scientists supported by NIDCD are continuing to make important progress on understanding the regeneration of sensory cells, unlocking the ways to accelerate their repair and return to normal function. This progress has resulted from the study of auditory and balance-related hair cells in birds. The research has stimulated hope that similar mechanisms can be initiated in mammals and, ultimately, humans, leading to the ability to reverse acquired hearing loss. Other
important NIDCD supported basic research has demonstrated that the olfactory neuroepithelium, located in the roof of the nose is known to have the remarkable capability of regenerating olfactory receptor neurons throughout life. The olfactory neuroepithelium produces another type of cell that migrates into the brain during adult life. Using both transplants and explants, scientists are now identifying the characteristics of these cells and defining the limits of their migration. The olfactory neuroepithelium is not only a source of olfactory receptor neurons, which have a powerful chemical trophic effect on the brain, but may also be a direct source of additional migratory cells for the brain.
Noise-induced hearing loss is the most common preventable cause of hearing loss and remains of great concern to the Institute. As a result of a NIDCDsponsored Consensus Development Conference on Noise and Hearing Loss, the Institute is engaged in an ongoing public education campaign. The first year of this effort to increase public awareness will be designed to reach intermediate elementary school children about high-risk activities.
The NIDCD recommends screening infants for hearing impairment; screening children prior to entering school; screening adolescents in the late teenage years when otosclerosis may set in; and, in the sixth decade of life, screening adults for presbycusis.
Early identification of hearing loss in infants is critical to language acquisition and development. NIDCD will sponsor a conference on reliable and costeffective ways of reducing the average age of diagnosis of hearing impairments in infants from the current two and one half years to the first several months of life. In addition, investigators are currently attempting to identify other factors present at age two which place a child at risk for long-term delay in talking. This research may identify which toddlers will benefit most from early,
The most common cause of progressive, conductive hearing loss in the adult with a normal eardrum is otosclerosis. An NIDCD-sponsored physician-scientist has found that a class of drugs, biphosphonates, act effectively to inhibit bone remodeling. If shown to be effective, these drugs could be used to prevent the onset of otosclerosis or to arrest the progression of the disease in persons who already have it.
Research is now in progress to correlate age-related hearing loss with alterations in neurotransmitter levels. Ultimately, this research may make it possible to delay the onset of presbycusis. Presbycusis is estimated to affect half of all persons between 51 and 91 years of age.
The Institute supports ongoing research in otitis media as it is the leading cause of acquired hearing loss in children under the age of ten. We were heartened by the release of a new vaccine for infants to prevent meningitis, a major cause of deafness in children.
Congenital cytomegalovirus (CMV) infection is a well-established cause of disorders of the auditory, visual and central nervous systems. The NIDCD will continue to support research on the CMV in association with disorders such as infant hearing loss, Meniere's disease, perilymphatic fistulae, sudden deafness, and hearing and balance disorders emerging in AIDS patients. CMV is the most. common secondary infection among AIDS patients and is estimated to occur in more than 90 percent of all such patients. Persons who have AIDS are known to develop communication disorders the most prominent of which is loss of hearing. studying whether the hearing loss is a result of the AIDS virus or the CMV. A model for studying congenital CMV inner ear infection has been developed, and therapeutic strategies have evolved for the prevention of the loss of hearing from
Additionally, the NIDCD is concerned with CMV in children.
72,000 children are born with CMV each year. CMV is the single largest cause of acquired, congenital hearing loss and is estimated to cause deafness in 2,000 to 4,000 infants annually in the United States.
In September 1990, the NIDCD held the first of a series of working group meetings designed to look at the needs of the several constituencies served by the Institute. Each working group has an opportunity to inform the Institute of their special research and research training needs. The first working group provided perspectives of the deaf community; the second, scheduled for April 1991, will provide the perspectives of oral, auditory hearing-impaired persons; the third, to be held in October 1991, will address the research and research training needs of women and women's health issues. The fourth meeting, planned for April 1992, will present the needs of minority persons and minority health issues; and, the final meeting in the series, scheduled for September 1992, will assess the impact of visual impairment on deaf and hard of hearing persons.
The Institute's National Strategic Research Plan has identified that there is insufficient incidence and prevalence data on communication disorders. After holding planning meetings with the National Center for Health Statistics (NCHS), the NIDCD is preparing a 10- to 15- year epidemiologic research strategy. This strategy in collaboration with the NCHS will yield incidence and prevalence data in the Institute's seven program areas and will provide reliable and cost-effective
data in a systematic and comprehensive manner. The NIDCD is establishing an Epidemiology Branch in FY 1991 to coordinate these efforts.
The NIDCD is continuing research and development of devices to improve the quality of life for hearing-impaired persons. The Institute has made a major investment in improving technology of auditory prostheses for the deaf. interleaved-pulse speech processor, developed and tested by NIDCD supported investigators, is capable of sampling the speech signal at high rates for use by patients fitted with multichannel cochlear implants. The processor provides impressive gains in understanding speech so important to these individuals. cochlear implant program has developed limited clinical trials of auditory prosthetic devices which have promise for major progress for individuals with congenital and acquired hearing impairment. Furthermore, the application of patterned electrical stimulation appears to help maintain the integrity of the central auditory pathways when the inner ear has been damaged. Another device, the digital hearing aid, is being studied with great intensity.
NIDCD will continue its initiatives in support of minority-related research and minority scientists. In several NIDCD-supported clinical trials on otitis media, specific attention has been devoted to minority populations. For reasons not yet clear, there is a higher incidence of otitis media among minority populations.
Although all clinical trials supported by NIDCD include both males and females, recent findings in diseases that affect women differentially include Meniere's disease, otosclerosis, and voice tremor.
Currently, NIDCD is supporting balance-related research on the micromechanical properties of inner ear sensory cells that may explain how these cells detect forces acting upon them during movement of the head and transform this information into neural signals.
Basic scientists studying the sense of smell have found an indication that some forms of Parkinson's disease and Alzheimer's disease may be caused by environmental agents that enter the brain through the olfactory nerve.
Recent research results indicate that normal language learning occurs only when exposure to the language begins early in life for both signed and spoken languages. In language research on adult aphasia, recent findings suggest that the immediate administration of Type I gangliosides in stroke patients may prevent
NIDCD investigators continue to study the onset and development of stuttering in early childhood. Preliminary results show that girls have a significantly
earlier onset, were more likely to have sudden onset, and show a stronger tendency for amelioration than boys.
NIDCD intramural scientists have demonstrated that botulinum toxin injections are effective in reversing the effects of muscle reinnervation and restoring the voice in the treatment of spasmodic dysphonia.
The first three National Multipurpose Research and Training Centers have been established. The Centers will stimulate important areas of basic and clinical research while providing needed research training opportunities. They will increase the numbers and broaden the capabilities of investigators in the communication sciences. Continuing education programs will disseminate research results to physicians, other health professionals and the public.
As we approach the new century, the age of communication is coming into maturity. Every aspect of human life is dependent upon skilled communication. Communication processes and technologies have become increasingly critical to success in the workplace. Persons with disabilities have been guaranteed the rights they have always deserved. However, when a child is born with a communication disorder or acquires one later in life, that child faces undeniable challenges throughout his or her lifetime. Often the challenges are economic. The earliest possible diagnosis and intervention are critical to improving the quality of life for individuals with communication disorders.
Research in molecular biology and, specifically, molecular genetics holds great promise for the use of gene therapy in hereditary deafness and other disorders of human communication that are clearly hereditary.
NIDCD has an ongoing commitment to research that develops strategies and devices to ensure the best possible outcomes for individuals with communication disorders. To the degree that these individuals are able to improve their productivity and independence, research will have contributed to major savings and, more importantly, to the quality of their lives. It is of the greatest importance that the age of communication is truly accessible to all Americans.
Mr. Chairman, the FY 1992 budget request is $146,321,000.
I will be pleased
to try to answer any questions you have.
BIOGRAPHICAL SKETCH OF DR. JAMES B. SNOW, JR.
Born: March 12, 1932, Oklahoma City, Oklahoma
Married, three children
B.S., University of Oklahoma, Norman, Oklahoma, 1946-49;