title: Hearing preservation in patients with unilateral vestibular schwannoma who undergo stereotactic radiosurgery: Reinterpretation of the auditory brainstem response.
abstract: BACKGROUND
  The objective of this study was to identify the prognostic factors for hearing preservation that would allow the more accurate stratification of patients who undergo stereotactic radiosurgery (SRS) for unilateral, sporadic vestibular schwannoma (VS).
  
  
  METHODS
  In total, 119 patients with VS who had serviceable hearing underwent SRS as primary treatment. The mean (±standard deviation) patient age was 48 ± 11 years, and the mean (±standard deviation) follow-up duration was 55.2 ± 35.7 months. The median marginal radiotherapy dose was 12.0 grays (Gy), and the mean (±standard deviation) tumor volume was 1.95 ± 2.24 cm(3) . The mean (±standard deviation) pure tone average (PTA) score was 26 ± 12 decibels (dB) (range, 4-50 dB), and the mean (±standard deviation) maximum speech discrimination score was 91 ± 12% (range, 52-100%). The mean (±standard deviation) baseline values for the interlatency (IL) of waves I and III (IL I-III) and the IL of waves I through V (IL I-V) on auditory brainstem response were 2.58 ± 0.60 milliseconds (mS) (range, 1.92-4.30 mS) and 4.80 ± 0.61 mS (range, 3.80-6.40 mS), respectively.
  
  
  RESULTS
  In multivariate analysis, the PTA score and IL I-V were significant and independent prognostic factors (hazard ratio, 1.072; 95% confidence interval, 1.046-1.098; P < .001; and hazard ratio, 1.534; 95% confidence interval, 1.008-2.336; P = .046, respectively). By using the PTA score and IL I-V, the patients were classified into 4 groups. The ratios of patients with serviceable hearing after SRS were 89.6%, 64.0%, 25.8%, and 6.7%, respectively, in Groups A through D (P < .001).
  
  
  CONCLUSIONS
  The current results indicated that the classification system based on using the PTA score and the IL I-V of the auditory brainstem response may be useful and specific for predicting the rate of hearing preservation in each individual.
authors.affiliation: Department of Neurosurgery, Seoul National University Bundang Hospital, Gyeonggi-do, Korea.
authors.forename: Jung Ho
authors.initials: JH
authors.lastname: Han
authors.forename: Dong Gyu
authors.initials: DG
authors.lastname: Kim
authors.forename: Hyun-Tai
authors.initials: HT
authors.lastname: Chung
authors.forename: Sun Ha
authors.initials: SH
authors.lastname: Paek
authors.forename: Chul-Kee
authors.initials: CK
authors.lastname: Park
authors.forename: Chae-Yong
authors.initials: CY
authors.lastname: Kim
authors.forename: Young-Hoon
authors.initials: YH
authors.lastname: Kim
authors.forename: Jin Wook
authors.initials: JW
authors.lastname: Kim
authors.forename: Yong Hwy
authors.initials: YH
authors.lastname: Kim
authors.forename: Sang Woo
authors.initials: SW
authors.lastname: Song
authors.forename: In Kyung
authors.initials: IK
authors.lastname: Kim
authors.forename: Hee-Won
authors.initials: HW
authors.lastname: Jung
mesh_terms: D000328:Adult; D016057:Evoked Potentials, Auditory, Brain Stem; D005260:Female; D034381:Hearing Loss / Q000209:etiology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009464:Neuroma, Acoustic / Q000601:surgery*; D011379:Prognosis; D016634:Radiosurgery / Q000009:adverse effects*