Document Detail


Clinical implications of experiments on alteration of the labyrinthine fluid pressures.
MedLine Citation:
PMID:  6343957     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Hearing is affected by changes in hydrostatic pressure of the perilymph, but very high pressures are required to produce a significant loss. Among the observed findings in cats are a rapidly reversible decrease in the sensitivity of the cochlear microphonic that is greater for low frequencies, harmonic distortion and reduction of dynamic range as measured by the input-output function for the cochlear microphonic, and a change in the summating potential from negative to positive. These changes are attributed to a temporary reduction in the size of the cochlear duct due to a shift of water molecules out of the cochlear duct into the blood until the resulting increase in osmotic pressure balances the increase in hydrostatic pressure. Consequently, the organ of Corti is biased "upward" away from the scala tympani. Increasing the hydrostatic pressure of the endolymph produces a "downward" biasing of the organ of Corti and has an opposite effect upon the summating potential. Presumably this is what happens in Meniere's disease. Because of the presence of the perilymphatic canaliculi, the locus of the hydrostatic pressure effect is assumed to be in the region of the reticular lamina. A theory has been developed to explain why cochlear function is very sensitive to relative differences between the hydrostatic pressures of the perilymph and the endolymph but is resistant to large variations in the absolute magnitudes of those pressures. Some of the clinical implications of this theory are discussed.
Authors:
G W Allen
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Publication Detail:
Type:  Journal Article; Review    
Journal Detail:
Title:  Otolaryngologic clinics of North America     Volume:  16     ISSN:  0030-6665     ISO Abbreviation:  Otolaryngol. Clin. North Am.     Publication Date:  1983 Feb 
Date Detail:
Created Date:  1983-07-15     Completed Date:  1983-07-15     Revised Date:  2007-11-15    
Medline Journal Info:
Nlm Unique ID:  0144042     Medline TA:  Otolaryngol Clin North Am     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  3-19     Citation Subset:  IM; S    
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MeSH Terms
Descriptor/Qualifier:
Animals
Cats
Cerebrospinal Fluid / physiology
Cochlear Aqueduct / physiology
Cochlear Microphonic Potentials
Ear, Inner / physiology*
Endolymphatic Sac / physiology*
Homeostasis
Humans
Hydrostatic Pressure
Labyrinthine Fluids / physiology*
Meniere Disease / physiopathology,  surgery
Organ of Corti / physiology
Perilymph / physiology
Posture

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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