Recently, we have demonstrated that as an experimental subject, the rabbit readily develops hydrops following surgical destruction of the endolymphatic duct and sac. The studies proposed here are designed to take advantage of the rabbit model to obtain details of the audiometric changes accompanying surgically induced endolymphatic hydrops in animal ears. These goals will be accomplished using the rabbit conditioned nictitating membrane response that has been well established by behavioral psychologists and modified by us for long-term psychoacoustic testing. Auditory sensitivity functions will be evaluated before and at specified time periods following surgical induction of hydrops. The pattern of audiometric deficit will be related to the precise location and magnitude of hydrops using quantitative morphometry of cochlear scalae of control and hydropic ears obtained from midmodiolar sections of celloidinembedded temporal bones. The ears will also be examined for evidence of ruptures of Reissner's membrane and patterns of hair-cell, spiral-ganglion cell, and nerve-fiber degeneration. Other functional changes to be studied include fluctuations in hearing sensitivity, threshold shifts induced by osmotic agents, and changes in vestibular responsiveness to caloric stimulation. The proposed investigations will provide the baseline data necessary for future studies of basic and clinically relevant aspects of the influence of endolymphatic hydrops on inner-ear function.

Agency
National Institute of Health (NIH)
Institute
National Institute of Neurological Disorders and Stroke (NINDS)
Type
Research Project (R01)
Project #
5R01NS022278-03
Application #
3404518
Study Section
Hearing Research Study Section (HAR)
Project Start
1985-04-01
Project End
1988-03-31
Budget Start
1987-04-01
Budget End
1988-03-31
Support Year
3
Fiscal Year
1987
Total Cost
Indirect Cost
Name
Baylor College of Medicine
Department
Type
Schools of Medicine
DUNS #
074615394
City
Houston
State
TX
Country
United States
Zip Code
77030
Martin, G K; Probst, R; Lonsbury-Martin, B L (1990) Otoacoustic emissions in human ears: normative findings. Ear Hear 11:106-20
Lonsbury-Martin, B L; Harris, F P; Stagner, B B et al. (1990) Distortion product emissions in humans. I. Basic properties in normally hearing subjects. Ann Otol Rhinol Laryngol Suppl 147:3-14
Ohlms, L A; Lonsbury-Martin, B L; Martin, G K (1990) The clinical application of acoustic distortion products. Otolaryngol Head Neck Surg 103:52-9
Lonsbury-Martin, B L; Harris, F P; Stagner, B B et al. (1990) Distortion product emissions in humans. II. Relations to acoustic immittance and stimulus frequency and spontaneous otoacoustic emissions in normally hearing subjects. Ann Otol Rhinol Laryngol Suppl 147:15-29
Martin, G K; Ohlms, L A; Franklin, D J et al. (1990) Distortion product emissions in humans. III. Influence of sensorineural hearing loss. Ann Otol Rhinol Laryngol Suppl 147:30-42
Lonsbury-Martin, B L; Martin, G K (1990) The clinical utility of distortion-product otoacoustic emissions. Ear Hear 11:144-54
Henley 3rd, C M; Owings, M H; Stagner, B B et al. (1990) Postnatal development of 2f1-f2 otoacoustic emissions in pigmented rat. Hear Res 43:141-8
Fermin, C D; Igarashi, M; Martin, G K et al. (1989) Ultrastructural evidence of repair and neuronal survival after labyrinthectomy in the squirrel monkey. Acta Anat (Basel) 135:62-70
Harris, F P; Lonsbury-Martin, B L; Stagner, B B et al. (1989) Acoustic distortion products in humans: systematic changes in amplitudes as a function of f2/f1 ratio. J Acoust Soc Am 85:220-9
Lonsbury-Martin, B L; Martin, G K; Probst, R et al. (1988) Spontaneous otoacoustic emissions in a nonhuman primate. II. Cochlear anatomy. Hear Res 33:69-93

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