Mr. Chairman and Members of the Committee, I am grateful to have this
opportunity to appear before you to report on the research progress of the National
Institute on Deafness and Other Communication Disorders (NIDCD) that benefits 46
million Americans who are challenged by diseases and disorders affecting hearing,
balance, smell, taste, voice, speech or language.
The progress we are experiencing within the portfolios of the NIDCD is due to
careful planning and accelerating discovery. Our scientists are studying the disorders
of human communication in revolutionary ways. Seven years ago, when I first
appeared before the Committee, I made a commitment that I would encourage the
development and expansion of the use of molecular biology to uncover important
information on how human communication systems work. With extramural expert
advice to increase the extramural portfolio of the NIDCD in molecular biology,
molecular genetics, imaging and integrative neuroscience, with a rigorously updated
NIDCD National Strategic Research Plan, and with the addition of an outstanding
molecular biologist as the Director of Intramural Research, we are seeing the results in
new understandings of the mechanisms involved in human communication.
Until the establishment of NIDCD in 1988, only two genes responsible for
hereditary hearing impairment had been located. In the past several years, with the
support of NIDCD and through NIDCD-supported international consortia designed for
the rapid exchange of information, a multitude of genes for syndromic and
nonsyndromic forms of hearing impairment, including autosomal dominant and
recessive, X-linked and mitochondrial modes of transmission have been located in
specific regions of the human genome. Presently, at least 12 different genes on 10
different chromosomes have been located for various forms of autosomal dominant
nonsyndromic hearing impairment and at least 11 different genes on as many different
chromosomes have been identified for autosomal recessive nonsyndromic hearing
impairment. The NIDCD has created an opportunity to accelerate discovery of the
specific genes involved in hearing impairment using inbred mouse strains, sample
sequencing and a cDNA library enriched for cochlear-specific cDNAs. This
information will ultimately aid in the earliest identification of hearing impairment in
infants. As these discoveries continue to be made, the NIDCD has started a new effort
to identify the underlying mechanisms of hereditary hearing impairment based on
functional analyses of the discovered genes.
During the early years of the NIDCD, investigators demonstrated that there is a
"window of opportunity" for acquiring sign language just as there is for children
acquiring spoken language and that they are parallel. Recent NIDCD-supported
research studied manual and vocal babbling in deaf and hearing children. This
research will further our understanding of normative patterns of motor development in
all children and provide a more detailed understanding of the acquisition of sign
languages in deaf children.
NIDCD has also taken a leadership role in the
improvement of clinical research
efforts in human communication. The Institute has established two clinical trial
cooperative groups with an estimated 15 to 20 clinical facilities in each group. These
facilities have clinical research experience and capability. The clinical trial
cooperative groups represent a five-year commitment for the initiation and conduct of
clinical trials. They will plan, implement, conduct, analyze, and disseminate results of
priority research in the efficacy of treatment of diseases and disorders affecting human
communication. This approach promises effective and efficient use of resources and
expedited delivery of research findings to the public.
The NIDCD is committed to improving technology for individuals with
communication disorders. Hearing aids continue to be the principal form of
remediation for most individuals with hearing loss. Although 28 million Americans
have hearing impairment, only about 20% of them have hearing aids. NIDCD with the
Department of Veterans Affairs (VA) supports an innovative collaboration to promote
hearing aid research and development. The first hearing aid clinical trial began in the
spring of 1996. It will determine which commonly used hearing aid circuits benefit
which subgroups of hearing-impaired individuals and under what circumstances.
Another important collaboration aimed at improving hearing aids, is a joint effort of
the NIDCD, the National Aeronautics and Space Administration (NASA) and the VA.
Beginning with a search of Federal laboratories for new technologies that might be
applicable to improving hearing aids, this collaboration is designed to foster the
formation and support of partnerships among scientists, industry and Federal
laboratories to carry out research needed for the commercialization of technologies that
could benefit those who use or could use hearing aids.
Computer and electronics industries are developing new and improved diagnostic
and rehabilitative tools for individuals with hearing impairment. For example,
scientists participating in the NIDCD Small Business Innovation Research (SBIR)
program are developing a cost-effective and user-friendly listening system designed to
interface with existing airplane sound systems. This will allow individuals with
hearing aids to receive pilot and flight attendant announcements that include safety
instructions, as well as to communicate with neighboring passengers. A collaboration
with a major airline is currently in place. In yet another effort, better tools for infant
hearing screening and diagnostic testing continue to be developed as many hospitals
implement universal infant hearing screening programs.
There is continuing progress in the testing of conjugate pneumococcal vaccines
against otitis media in infants and small children. Last year I reported to the Committee
that we had a new preventive strategy against the nontypeable Haemophilus influenzae
(NTHi). NIDCD intramural scientists have successfully prepared a detoxified
lipooligosaccharide (dLOS)-based conjugate antigen from NTHi. This conjugate
antigen induces a bactericidal humoral immune response in two animal species and
reduces the incidence of otitis media in the only reliable animal model of otitis media,
making it a promising vaccine candidate. Plans are underway to initiate a Stage I
clinical trial of this vaccine in the NIH Clinical Center. I am delighted to announce that
in cooperation with the NICHD, an announcement for commercial development of the
vaccine has just been published. As the NTHi genome has recently been sequenced,
this new knowledge will facilitate understanding of the pathogenesis of NTHi otitis
media and ultimately accelerate the development of other vaccines against NTHi otitis
media. Additionally, the Otitis Media Vaccine Unit in the NIDCD is beginning work on
a candidate vaccine against M. catarrhalis otitis media.
Chronic otitis media (OM) in children causes hearing loss, is responsible for major
health care costs, and is a risk factor for delaying the acquisition of language. In the
general population, many risk factors for OM have been identified, but their
applicability in populations such as Native American children, with a higher incidence
of otitis media, is not known. Studying OM risk factors in a population with a high
incidence of this disease could elucidate the role of certain risk factors in both majority
and minority populations. A NIDCD-funded investigator is currently working with
mothers on the White Earth Reservation to examine risk factors for OM in Native
American children. The protocol includes hearing screening and tympanometry for the
Native American children. Results to date suggest a high rate of chronic OM in this
group (approaching 50%), with half of the affected children exhibiting an associated
hearing loss.
NIDCD scientists are comparing mechanisms underlying apoptosis or cell death
with mechanisms of plasticity to promote regeneration of sensory capabilities lost to
disease. Cochlear hair cells that are lost are not naturally replaced, resulting in
permanent hearing loss. Current research efforts have focused on the role of growth
factors and other mitogens in promoting hair cell regeneration. This approach provides
a new avenue for investigating mechanisms of hair cell regeneration and repair in
mammalian systems and promises to accelerate the discovery of therapeutic agents for
the prevention and treatment of sensorineural hearing loss and vestibular (balance)
abnormalities.
Disorders of balance and vestibular function constitute a major health problem.
Individuals who suffer from recurrent debilitating vertigo, dizziness, or imbalance are
often unable to hold jobs and unable sometimes to get up in the morning and perform
simple acts of daily living such as showering, eating, or driving. It is estimated that 12.5
million Americans over the age of 65 have dizziness or balance problems that
significantly interfere with their lives, and many of these individuals have difficulty
caring for themselves independently. To assess the functional skills of individuals with
chronic balance problems of vestibular origin, a NIDCD-supported investigator has
developed and validated a scale of independence in activities of daily living. The scale
developed in this study provides clinicians who manage individuals with balance
disorders with a useful tool to evaluate the outcomes of newly developed treatment.
The chemical senses (smell and taste) permit interaction with the environment in
highly complex ways. Smell and taste greatly influence nutrition. Eating disorders
comprise a rapidly growing group of medical problems. Many individuals are afflicted
with eating disorders such as anorexia that can result in malnutrition, wasting, or even
death. Scientists have found some surprising results regarding the effect of gustatory (or
taste) thalamic lesions on behavior that challenge earlier concepts of how taste
information is processed by the gustatory thalamus and what its role is in guiding eating
behavior. These results suggest that the gustatory thalamus is not simply a relay station
for transmitting primitive, consummatory aspects of gustatory information from the
brainstem to higher cortical centers, but that it plays a more pivotal role in the learning
and execution of more complex tasks. Work in progress includes the investigation of the
role of the gustatory thalamus in the information-processing of conditioned food
aversions and food-seeking behavior.
For the working adult who becomes suddenly deafened by illness or injury, there had
in earlier times been no way to maintain his or her former life, but with the development
and improvement of cochlear implants, the neural prostheses that work by providing
direct electrical stimulation to the auditory nerve, many of these individuals can
maintain their jobs, talk on the phone and interact more easily with families and friends.
NIDCD is especially proud of three efforts designed to support minority scientists
underrepresented in the area of human communication research. All are in collaboration
with the Office of Research in Minority Health (ORMH) and include the
NIDCD/ORMH Minority Dissertation Research Grants in Human Communication and
the NIDCD/ORMH Mentored Research Scientist Development Award for Minority
School Faculty. The NIDCD/ORMH Partnership Program is a pilot collaboration
between NIDCD and four academic institutions with large minority enrollments. The
program, in its third year, develops curriculum materials and workshops and provides
research training for students and faculty and research administration experience for
faculty and administrators. Building on an idea of a human infrastructure, several
hundred individuals have participated in the program at the universities or the NIDCD.
The scientists supported by the NIDCD are applying the newest tools and strategies to
long misunderstood and often misdiagnosed diseases and disorders of human
communication. The NIDCD is seizing opportunities to accelerate discovery that will
lead to: elucidation of the biology of brain disorders such as aphasia; finding new
approaches to pathogenesis in diseases including laryngeal carcinoma and spasmodic
dysphonia; new treatment strategies against autoimmune inner ear disease; applying
genetic medicine to hearing impairment and velo-cardio-facial syndrome, while
developing new therapy for disorders of balance and the symptom of tinnitus that are
critically important in improving the quality of life for those challenged with
communication disorders.
Mr. Chairman, the FY 1998 budget request for NIDCD is $192,447,000. I will be
pleased to answer any questions you might have.
