title: [Diagnostic value of middle ear resonant frequency in hydrotympanum].
abstract: OBJECTIVE
  To investigate the diagnostic value of 226 Hz tympanometry and middle ear resonant frequency (RF) in adults with hydrotympanum. Discuss whether the resonant frequency combined with conventional 226 Hz tympanometry could increase the effectiveness for diagnosis of hydrotympanum.
  
  
  METHODS
  Prospective study was applied to compare the normal hearing group and the test group. The otoscopic findings, pure tone audiometry and GSI-33 middle ear analyzer were considered standard. A 90% range of RF values from normal hearing group was considered standard to distinguish normal from abnormal RF values in test group. The subjects who had type B, C or abnormal tympanograms were performed with tympanocentesis. Hydrotympanum were confirmed when the results were positive.
  
  
  RESULTS
  The middle ear resonant frequency in adults range from 900 Hz to 1100 Hz was considered normal. There was found to be a statistically significant decrease in RF values in ears with OME compared to normative data (P<0.01). The positive percentage of tympanocentesis on type "B" tympanograms were 83%, which was significantly higher than that of tympanocentesis on type "C" or abnormal tympanograms (P<0.05). The positive percentage of tympanocentesis was 0 when the resonant frequency was normal. The positive percentage of tympanocentesis which the resonant frequency were less than 500 Hz were significantly higher than the subjects whose resonant frequency were more than 500 Hz.
  
  
  CONCLUSIONS
  Middle ear resonant frequency testing has very important clinic value for diagnosis of hydrotympanum, especially for those patients with type C or abnormal tympanograms.
authors.affiliation: Department of Otolaryngology-Head and Neck Surgery, the Affiliated Hospital of Luzhou Medical College, Luzhou, 646000, China. ld_lz@126.com
authors.forename: Dan
authors.initials: D
authors.lastname: Lai
authors.forename: Shixi
authors.initials: S
authors.lastname: Liu
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D001301:Audiometry, Pure-Tone; D004432:Ear, Middle / Q000502:physiology*; D005260:Female; D006320:Hearing Tests; D006801:Humans; D008297:Male; D008875:Middle Aged; D010034:Otitis Media with Effusion / Q000175:diagnosis* / Q000503:physiopathology*; D011446:Prospective Studies; D055815:Young Adult