Document Detail


Electrocochleography during experimental cochlear ischemia of the guinea pig.
MedLine Citation:
PMID:  8725526     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
It has been postulated that impairment of cochlear blood flow (CoBF) is one of the most important causes of hearing loss occurring during acoustic neuroma (AN) surgery. However, it remains unclear how the degree of cochlear ischemia influences the evoked responses in electrocochleography. (ECochG) which has been used for monitoring cochlear functions. In the present study, we investigated alterations in ECochG during cochlear ischemia of varying degree in the guinea pig. In order to induce cochlear ischemia, the anterior inferior cerebellar artery (AICA) was mechanically compressed via the transclival approach. The compression of AICA resulted in the reduction of CoBF in 55 out of 70 guinea pigs. A constant reduction of CoBF was maintained during the compression of AICA in 44 (63%) guinea pigs. CoBF abruptly decreased upon compressing AICA, and promptly recovered after releasing the compression. N1 and N2 in ECochG were also altered by compression. During 3-min ischemia, N1 and N2 disappeared in 36% and 41% of the cases, respectively. The residual CoBF in cases whose N1 and N2 disappeared was significantly lower than that in other cases whose N1 and N2 were sustained during 3-min ischemia. In addition, there was a tendency that the lower the residual CoBF was, the shorter the survival time of N1 and N2. In cases whose N1 and N2 did not disappear, the prolongation of N1 and N2 latencies after 3-min ischemia was positively correlated to the residual CoBF. On the basis of these results, we discuss the mechanisms underlying the changes in CoBF and ECochG during cochlear ischemia, and conclude that the degree of cochlear ischemia during AN surgery can be estimated with ECochG.
Authors:
K Ogawa; J Kanzaki; S Ogawa; N Tsuchihashi; Y Inoue; M Sato; S Ikeda
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Publication Detail:
Type:  Journal Article    
Journal Detail:
Title:  Acta oto-laryngologica     Volume:  116     ISSN:  0001-6489     ISO Abbreviation:  Acta Otolaryngol.     Publication Date:  1996 Mar 
Date Detail:
Created Date:  1996-11-07     Completed Date:  1996-11-07     Revised Date:  2003-11-14    
Medline Journal Info:
Nlm Unique ID:  0370354     Medline TA:  Acta Otolaryngol     Country:  NORWAY    
Other Details:
Languages:  eng     Pagination:  253-6     Citation Subset:  IM    
Affiliation:
Department of Otolaryngology, School of Medicine, Keio University.
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MeSH Terms
Descriptor/Qualifier:
Animals
Audiometry, Evoked Response*
Cochlea / blood supply,  physiopathology*
Guinea Pigs
Ischemia / physiopathology*
Vestibulocochlear Nerve / physiopathology

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