title: Ipsilateral and contralateral acoustic brainstem response abnormalities in patients with vestibular schwannoma.
abstract: OBJECTIVE
  To analyze auditory brainstem response (ABR) data in patients with vestibular schwannomas (VS) in an effort to identify correlations between abnormal ABR parameters and tumor size.
  
  
  METHODS
  Cross-sectional study with chart review.
  
  
  METHODS
  Tertiary referral hospital.
  
  
  METHODS
  Retrospective chart review and analysis of bilateral ABR records in patients with VS. Interaural latency differences of interpeak I-V (ILD-I-V) and ILD-V longer than 0.2 ms were used as abnormal criteria.
  
  
  RESULTS
  Thirty patients with a mean age of 50 +/- 14 years were included in this study. The most frequent changes in ABR parameters included those of ILD-I-V (100%), wave V latency (96.7%), ILD-V (93.3%), and interpeak I-V latency (90%). Average VS tumor size was 2.48 +/- 1.31 cm. For patients with VS greater than or equal to 2 cm, the prevalences of abnormal ipsilateral interpeak III-V latency, contralateral wave V latency, and interpeak III-V latency showed statically significant differences (P = 0.0035, P = 0.0267, and P = 0.0273, respectively) compared to those in patients with VS less than 2 cm. Tumor size was positively correlated with pure-tone average (P = 0.0106) and with the total number of bilateral abnormal ABR parameters (P = 0.004).
  
  
  CONCLUSIONS
  We identified a correlation between ABR parameters and VS tumor size. An ipsilateral ILD-I-V greater than 0.2 ms was sensitive for detecting VS. Abnormal contralateral wave V and interpeak III-V latency indicated a tumor size potentially larger than 2 cm. Further studies are needed to confirm these findings.
authors.affiliation: Department of Otolaryngology, National Taiwan University Hospital Yun-Lin Branch, Yun-Lin, Taiwan.
authors.forename: Chien
authors.initials: C
authors.lastname: Shih
authors.forename: Fen-Yu
authors.initials: FY
authors.lastname: Tseng
authors.forename: Te-Hei
authors.initials: TH
authors.lastname: Yeh
authors.forename: Chuan-Jen
authors.initials: CJ
authors.lastname: Hsu
authors.forename: Yuh-Shyang
authors.initials: YS
authors.lastname: Chen
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D001301:Audiometry, Pure-Tone; D003430:Cross-Sectional Studies; D016057:Evoked Potentials, Auditory, Brain Stem / Q000502:physiology*; D005260:Female; D006801:Humans; D016014:Linear Models; D008297:Male; D008875:Middle Aged; D009464:Neuroma, Acoustic / Q000503:physiopathology*; D012189:Retrospective Studies; D014724:Vestibular Function Tests