title: Is the nerve origin of the vestibular schwannoma correlated with vestibular evoked myogenic potential, caloric test, and auditory brainstem response?
abstract: CONCLUSIONS
  The results of the caloric test, vestibular evoked myogenic potential (VEMP), and auditory brainstem response (ABR) in patients with vestibular schwannoma (VS) did not show clear correlation with the nerve origin of the tumor but with tumor size. When we focused on patients with VS within the internal acoustic canal (IAC), neither the nerve origin of the tumor nor the tumor size showed clear correlation with the results of these tests.
  
  
  OBJECTIVE
  This study examined the correlation of the nerve origin of VS, superior or inferior vestibular nerve, with the results of function tests.
  
  
  METHODS
  Subjects comprised 109 consecutive patients diagnosed as having unilateral VS. Each test was performed before surgery. Tumor size was measured with preoperative MRI.
  
  
  RESULTS
  The nerve origin of the tumor was identified in 63 of the 109 patients. The percentage of patients showing abnormal responses in each test was not different between 37 patients with superior VS and 26 patients with inferior VS. Also, no difference was observed for patients with VS within the IAC. Mean tumor size in patients showing abnormal responses was larger than that in patients showing normal responses on each test. However, this tendency was not observed for patients with VS within the IAC.
authors.affiliation: Department of Otolaryngology, Graduate School of Medicine, University of Tokyo, Tokyo. IZT01356@nifty.ne.jp
authors.forename: Munetaka
authors.initials: M
authors.lastname: Ushio
authors.forename: Shinichi
authors.initials: S
authors.lastname: Iwasaki
authors.forename: Yasuhiro
authors.initials: Y
authors.lastname: Chihara
authors.forename: Nobutaka
authors.initials: N
authors.lastname: Kawahara
authors.forename: Akio
authors.initials: A
authors.lastname: Morita
authors.forename: Nobuhito
authors.initials: N
authors.lastname: Saito
authors.forename: Toshihisa
authors.initials: T
authors.lastname: Murofushi
mesh_terms: D000328:Adult; D000368:Aged; D002150:Caloric Tests; D016057:Evoked Potentials, Auditory, Brain Stem; D006801:Humans; D008875:Middle Aged; D009464:Neuroma, Acoustic / Q000209:etiology* / Q000473:pathology / Q000503:physiopathology; D058585:Vestibular Evoked Myogenic Potentials; D014725:Vestibular Nerve / Q000473:pathology / Q000503:physiopathology; D055815:Young Adult