title: Natural history of hearing deterioration in intracanalicular vestibular schwannoma.
abstract: BACKGROUND
  Intracanalicular vestibular schwannomas have a range of treatment options that can preserve hearing: microsurgery, stereotactic radiotherapy, and conservative observation.
  
  
  OBJECTIVE
  To evaluate the natural course of hearing deterioration during a period of conservative observation.
  
  
  METHODS
  A retrospective case review was performed on 47 patients with a unilateral intracanalicular vestibular schwannoma. Evaluation of growth was monitored by repeat MRI scanning. Repeated pure-tone and speech audiometry results were evaluated for subgroups of patients showing growth or no growth and by subsite location of tumor in the internal auditory canal.
  
  
  RESULTS
  Patients had a mean follow-up of 3.6 years. Over the entire population, the pure-tone average thresholds at 0.5, 1, 2, and 3 kHz and the word recognition scores both significantly deteriorated from 38 to 51 dB HL, and from 66% to 55%, respectively. Overall, 74% of subjects with good hearing, according to the 50/50 rule, maintained hearing above this rule. There were no significant differences in hearing loss by subsite in the internal auditory canal (porus, fundus, central) or by growth status (stable, growing, shrinking). Only 6 patients showed a large hearing change. This happened early during follow-up, with relatively stable hearing after this.
  
  
  CONCLUSIONS
  Hearing will deteriorate in some intracanalicular vestibular schwannomas, regardless of tumor growth. Hearing deterioration, if on a large scale, most likely occurs early in follow-up. The present results using conservative management in these tumors appear similar to those reported for stereotactic radiotherapy or microsurgery.
authors.affiliation: Division of Otolaryngology--Head & Neck Surgery, Department of Surgery, Dalhousie University, Halifax, Nova Scotia, Canada. r.pennings@kno.umcn.nl
authors.forename: Ronald J E
authors.initials: RJ
authors.lastname: Pennings
authors.forename: David P
authors.initials: DP
authors.lastname: Morris
authors.forename: Linda
authors.initials: L
authors.lastname: Clarke
authors.forename: Stefan
authors.initials: S
authors.lastname: Allen
authors.forename: Simon
authors.initials: S
authors.lastname: Walling
authors.forename: Manohar L
authors.initials: ML
authors.lastname: Bance
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D034381:Hearing Loss / Q000209:etiology*; D006320:Hearing Tests; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009464:Neuroma, Acoustic / Q000150:complications* / Q000473:pathology*; D012189:Retrospective Studies