title: Distortion-product otoacoustic emission tests evaluate cochlear function and differentiate cochlear and vestibular schwannoma.
abstract: OBJECTIVE
  (1) To investigate cochlear function in patients with acoustic neuroma by distortion-product otoacoustic emission tests and (2) to evaluate the utility of this method for identifying the nerve origin of acoustic neuroma.
  
  
  METHODS
  Diagnostic test assessment.
  
  
  METHODS
  Community hospital.
  
  
  METHODS
  The study included 196 patients with unilateral acoustic neuroma who were surgically treated in our hospital between April 2008 and March 2011. In all patients, pure-tone audiometry and distortion-product otoacoustic emission tests were conducted before surgery, and tumor size was measured on magnetic resonance imaging.
  
  
  RESULTS
  Superior vestibular schwannoma (n = 112), inferior vestibular schwannoma (n = 80), and cochlear schwannoma (n = 4) were observed. Positive results of distortion-product otoacoustic emission tests were observed in 11 patients with superior vestibular schwannoma, 14 with inferior vestibular schwannoma, and 3 with cochlear schwannoma. They were predictive of cochlear schwannoma, with 75.0% sensitivity (95% confidence interval [CI], 30.6-95.4) and 87.0% specificity (95% CI, 86.1-87.4). Retrocochlear hearing loss was detected in 5 patients with inferior vestibular schwannoma and 1 with cochlear schwannoma. It was also predictive of cochlear schwannoma. This criterion showed 25.0% sensitivity (95% CI, 4.7-66.1) and 97.4% specificity (95% CI, 97.0-98.3).
  
  
  CONCLUSIONS
  Percentages of patients with positive results on distortion-product otoacoustic emission tests and those with retrocochlear hearing loss differed by nerve origin. Distortion-product otoacoustic emission tests can be of some assistance in differentiating cochlear and vestibular schwannoma.
authors.affiliation: Department of Otolaryngology, Tokyo Metropolitan Police Hospital, Nakano-ku, Tokyo, Japan. kagoya-tky@umin.ac.jp
authors.forename: Ryoji
authors.initials: R
authors.lastname: Kagoya
authors.forename: Masanobu
authors.initials: M
authors.lastname: Shinogami
authors.forename: Michihiro
authors.initials: M
authors.lastname: Kohno
authors.forename: Tatsuya
authors.initials: T
authors.lastname: Yamasoba
mesh_terms: D000328:Adult; D000704:Analysis of Variance; D001309:Auditory Threshold / Q000502:physiology; D002151:Calorimetry; D016009:Chi-Square Distribution; D003051:Cochlea / Q000503:physiopathology* / Q000601:surgery; D005260:Female; D006319:Hearing Loss, Sensorineural / Q000503:physiopathology*; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009464:Neuroma, Acoustic / Q000503:physiopathology* / Q000601:surgery; D017084:Otoacoustic Emissions, Spontaneous / Q000502:physiology*; D011237:Predictive Value of Tests; D012181:Retrocochlear Diseases / Q000503:physiopathology; D012680:Sensitivity and Specificity; D058585:Vestibular Evoked Myogenic Potentials / Q000502:physiology