title: Extratympanic electrocochleography: diagnostic and predictive value.
abstract: OBJECTIVE
  To define the clinical value of extratympanic electrocochleography (ECoG) in the diagnosis of Meniere's disease.
  
  
  METHODS
  Retrospective case review.
  
  
  METHODS
  An otology/neurotology referral center.
  
  
  METHODS
  A group of 252 patients with symptoms consistent with Meniere's disease and 20 normal-hearing control subjects.
  
  
  METHODS
  All patients underwent audiologic testing and extratympanic ECoG at the time of initial evaluation and, when possible, following treatment.
  
  
  METHODS
  Audiologic thresholds and summating and action potential ratios (SP:AP).
  
  
  RESULTS
  Patients were classified into definite, probable, possible, and bilateral Meniere's disease groups according to American Academy of Otolaryngology-Head and Neck Surgery (AAO-HNS) guidelines. The definite Meniere's group demonstrated an elevated SP:AP ratio in 74% of cases, the possible Meniere's group in 64%, and the bilateral group demonstrated elevated ratios in both ears in 66%. Contralateral ears produced elevated ratios in 42% for unilateral cases, whereas 40% of these ears reported at least one contralateral symptom. All 40 control ears were normal (SP:AP > or = 0.50). Results statistically correlated (p = 0.004) with the Meniere's staging system set forth in the 1995 AAO-HNS guidelines. No correlation was found between ECoG results and disease duration. Although 72% of the 86 follow-up patients reported complete or substantial vertigo control, changes from initial ECoG results did not specifically correlate to vertigo, tinnitus, or aural fullness improvement.
  
  
  CONCLUSIONS
  Extratympanic ECoG can be useful in the diagnosis of Meniere's disease, lending promise to possible cases where objective audiologic data are lacking. Each testing center should study its own results to establish meaningful parameters and confidence levels.
authors.affiliation: Pappas Ear Clinic, Birmingham, Alabama 35233, USA.
authors.forename: D G
authors.initials: DG
authors.lastname: Pappas
authors.forename: D G
authors.initials: DG
authors.lastname: Pappas
authors.forename: L
authors.initials: L
authors.lastname: Carmichael
authors.forename: D P
authors.initials: DP
authors.lastname: Hyatt
authors.forename: L M
authors.initials: LM
authors.lastname: Toohey
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001300:Audiometry, Evoked Response / Q000379:methods*; D005260:Female; D006801:Humans; D008297:Male; D008575:Meniere Disease / Q000175:diagnosis*; D008875:Middle Aged; D011237:Predictive Value of Tests; D012189:Retrospective Studies; D012720:Severity of Illness Index; D014432:Tympanic Membrane / Q000502:physiology*