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QUESTIONS SUBMITTTED BY SENATOR MARK O. HATFIELD
SLEEP DISORDERS AND NARCOLEPSY
Question. Dr. Goldstein, would you summarize for the Subcommittee research being supported by the NINDS research on sleep disorders such as narcolepsy?
Answer. NINDS-supported sleep research includes investigation of how the brain controls the normal sleep-wake cycle and what occurs in disorders of this cycle, such as narcolepsy. A clinical research center supported by NINDS is conducting collaborative basic science and clinical research exploring molecular genetic, immunologic, and neurophysiologic hypotheses for the pathogenesis of sleep disorders. Other clinical investigators are developing improved drug therapy for narcolepsy, studying the mechanisms for "rebound insomnia" following discontinuation of sleep-promoting medications, and evaluating techniques to improve the sleep patterns of shift workers with rotating day and night schedules.
Linkage markers for the autosomal recessive gene responsible for canine narcolepsy have been identified and researchers are working to isolate and sequence the gene. When this is accomplished, the abnormal gene product can be identified and strategies developed to counter the activity of the abnormal gene product. This research with dogs should have important implications for human narcolepsy.
Question. Dr. Goldstein, it is my understanding that years ago many believed that because narcolepsy and epilepsy patients displayed similar symptoms, that a link existed between the two disorders. What is the present understanding today?
Answer. Years ago a number of neurological disorders, such as tics, muscle jerks, and narcolepsy were misclassified as epilepsy. It is fairly common for two disorders to have similar symptoms but entirely different causes, prognoses, and treatments. Narcolepsy and epilepsy are similar in that they are both episodic, or "paroxysmal" disorders of the brain, and in the case of most epilepsy and all narcolepsy, there is little anatomical change in the brain that can explain the disorder. Electrophysiologically and behaviorally there is overlap between epilepsy and sleep disorders, in that seizures can affect sleep, and sleep has a strong impact on the occurrence of seizures. However, testing with modern electrophysiological techniques has shown that the characteristic brain electrical features of narcolepsy and epilepsy are quite distinct.
Question. Is it still prudent for research on narcolepsy to be conducted through the epilepsy branch or should a separate branch on sleep be established?
Answer. The Institute provides research support for a large number of neurological disorders. Each scientific division or branch of the NINDS is assigned responsibility for a variety of disorders not necessarily reflected in the name of that unit. Epilepsy Branch presently has responsibility for the support of essentially all clinical and basic electrophysiological research related to a variety of paroxysmal or episodic disorders such as epilepsy, myoclonus, narcolepsy, and circadian rhythms. Because of similarities in the technical expertise needed to diagnose and manage these disorders, it is more efficient for the research support to be within the same unit. Creation of separate branches for sleep and other neurological disorders would fragment the research effort, and require extensive duplication of scarce scientific resources.
NATIONAL INSTITUTE ON DEAFNESS AND OTHER COMMUNICATION DISORDERS
STATEMENT OF DR. JAMES B. SNOW, JR., DIRECTOR
Senator HARKIN. Dr. Snow, your budget request of $146.3 million is 8.4 percent above 1991.
We are now close to your first anniversary as the first Director of the National Institute on Deafness and Other Communication Disorders. The committee is delighted to have you back here with us today, and please proceed with your statement.
Dr. SNOW. Thank you very much, Senator. It is a privilege to be here before the committee to discuss the programs of the National Institute on Deafness and Other Communication Disorders.
In the past 22 years since the creation of the Institute, we have seen an increased vigor in part of the scientific community. There has been an outpouring of very high quality applications to our Institute. We received 254 applications in 1989, 350 in 1990, and 472 this year, and we conservatively estimate that there will be 546 in 1992. And this represents an increase of over 100 percent since 1989.
As we discussed last year, 1 in 1,000 infants are born deaf, and 50 percent of those have a cause that is attributable to a genetic defect. Just yesterday, I learned from the Waardenburg syndrome consortium that we organized and support that they have now located the gene within one centiMorgan on chromosome 2, and this is an important breakthrough in hereditary deafness.
REGENERATION OF SENSORY CELLS
We are also making progress in understanding the regeneration of sensory cells, unlocking ways to accelerate their repair and return to normal function. This progress has resulted from the study of avian auditory and balance related hair cells. The research has stimulated the hope that similar mechanisms can be initiated in mammals and ultimately in humans leading to the ability to reverse acquired hearing loss.
The olfactory neuroepithelium is known to have a remarkable capability of regenerating olfactory receptor neurons throughout life. The olfactory neuroepithelium also produces another cell that migrates into the brain during adult life, and we are supporting scientists studying the characteristics of these cells and defining the limits of their migration.
The early identification of hearing loss in infants is critical to language acquisition and development. The NIDCD is searching for reliable and cost-effective ways to reduce the average age of diag
nosis of hearing impairment in infants from the current 22 years to the first several months of life.
The NIDCD has made major investments in the development and improvement of multichannel cochlear implants, including a new interleaved-pulse speech processor capable of sampling speech at high rates. This processor provides impressive gains in understanding speech so important to these individuals. Scientists studying the sense of smell have found an indication that some forms of Parkinson's disease and Alzheimer's disease are caused by environmental agents that enter the brain through the olfactory nerve.
The NIDCD will continue to support minority-related research and minority scientists. In several NIDCD-supported clinical trials on otitis media, specific attention has been devoted to minority populations.
Although all clinical trials, supported by the NIDCD include both males and females, recent findings indicate that there are diseases affecting women differentially including Meniere's disease, otosclerosis, and voice tremor.
This budget request places emphasis on basic research to improve our understanding of human communication while supporting clinical trials for prevention, therapeutic intervention, and the development of devices that will improve the quality of the lives of those who already are experiencing the challenges of communication disorders.
Mr. Chairman, the fiscal year 1992 budget request is for $146,321,000.
I will be pleased to try to answer any questions you have. [The statement follows:]