PMID- 1584587
OWN - NLM
STAT- MEDLINE
DCOM- 19920618
LR  - 20180217
IS  - 0301-1569 (Print)
IS  - 0301-1569 (Linking)
VI  - 54
IP  - 1
DP  - 1992
TI  - Pathogenesis of widened AP-SP complex in cases of cerebellopontine angle tumors.
PG  - 15-20
AB  - Pathogenesis of widened AP-SP complexes often noted in electrocochleograms 
      (ECochGs) in cases of cerebellopontine angle tumors remains unclear. As acoustic 
      neuromas usually originate from the vestibular nerve, some changes in this nerve 
      might be involved in producing the broadened waveform. Effects of lidocaine on 
      the AP-SP complex were investigated in guinea pigs by injecting this compound 
      into the root exit zone of the vestibular nerve, where the cochlear efferent 
      fibers run together. The AP-SP complex in response to clicks and tone bursts was 
      recorded at the bony wall of the scala vestibuli in the basal turn of the 
      cochlea. Inactivation of the efferent cochlear fibers resulted in a marked 
      widening of the waveform, independent of the interstimulus intervals (ISIs). This 
      broad wave was composed of a DC shift which was quite similar to the envelope 
      curve of the acoustic stimuli. Although the effect of activity of the efferent 
      cochlear fibers on negative summating potential (SP) has not been reported in 
      detail, the authors concluded that the broad waveform observed in ECochGs in 
      cases with cerebellopontine angle tumors was caused by enhanced negative SP due 
      to inactivation of efferent cochlear fibers.
FAU - Takeda, T
AU  - Takeda T
AD  - Department of Otolaryngology, Kochi Medical School, Japan.
FAU - Kitahara, M
AU  - Kitahara M
FAU - Sawada, I
AU  - Sawada I
LA  - eng
PT  - Journal Article
PL  - Switzerland
TA  - ORL J Otorhinolaryngol Relat Spec
JT  - ORL; journal for oto-rhino-laryngology and its related specialties
JID - 0334721
SB  - IM
MH  - Animals
MH  - *Audiometry, Evoked Response
MH  - Cerebellar Neoplasms/*physiopathology
MH  - *Cerebellopontine Angle
MH  - *Evoked Potentials, Auditory
MH  - Guinea Pigs
EDAT- 1992/01/01 00:00
MHDA- 1992/01/01 00:01
CRDT- 1992/01/01 00:00
PHST- 1992/01/01 00:00 [pubmed]
PHST- 1992/01/01 00:01 [medline]
PHST- 1992/01/01 00:00 [entrez]
AID - 10.1159/000278935 [doi]
PST - ppublish
SO  - ORL J Otorhinolaryngol Relat Spec. 1992;54(1):15-20. doi: 10.1159/000278935.