title: Comparison of the use of tympanic and extratympanic electrodes for electrocochleography.
abstract: OBJECTIVE
  To determine the differences between tympanic and extratympanic electrodes regarding recording technique, comfort and ease of execution of the exam, and quality of auditory potential tracings.
  
  
  METHODS
  Prospective cross-section investigation.
  
  
  METHODS
  Determination of the summation potential/action potential (SP/AP) ratio by electrocochleography (EchoG) using tympanic and extratympanic electrodes and separate analysis of SP and AP regarding the amplitude recorded.
  
  
  RESULTS
  Twenty-three subjects (15 men and 8 women; mean age: 33.17 years) with normal tonal threshold audiometry were evaluated. EchoG analysis revealed no significant difference between the two tympanic electrodes. Eleven of the 23 subjects reported discomfort with the insertion of the tympanic electrode even with the use of topical xylocaine, whereas no complaints of discomfort were reported with the use of the extratympanic electrode.
  
  
  CONCLUSIONS
  Both electrodes were effective for EchoG evaluation, but the extratympanic one was easier to insert and did not cause discomfort. However, the tympanic electrode produced tracings of greater amplitude and of better reproducibility.
authors.affiliation: Department of Ophthalmology, University Hospital, Faculty of Medicine of Ribeirão Preto, USP, Ribeirão Preto, SP, Brazil.
authors.forename: Ariane Solci
authors.initials: AS
authors.lastname: Bonucci
authors.forename: Miguel Angelo
authors.initials: MA
authors.lastname: Hyppolito
mesh_terms: D000328:Adult; D001300:Audiometry, Evoked Response / Q000295:instrumentation*; D001309:Auditory Threshold / Q000502:physiology; D003430:Cross-Sectional Studies; D004867:Equipment Design; D005072:Evoked Potentials, Auditory / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D008839:Microelectrodes / Q000592:standards / Q000706:statistics & numerical data*; D008875:Middle Aged; D011446:Prospective Studies; D012016:Reference Values; D014432:Tympanic Membrane; D055815:Young Adult