title: Extratympanic electrocochleography in the diagnosis of auditory neuropathy/auditory dyssynchrony.
abstract: The brainstem auditory evoked potential (BAEP) is being extensively used as a method for the evaluation of cochlear function in individuals with diagnosis of auditory neuropathy/auditory dyssynchrony (AN/AD). In the absence of otoacoustic emissions, many cases of AN/AD have been diagnosed by the presence of CM identified in the BAEP.
  
  
  OBJECTIVE
  to demonstrate the clinical applicability of extratympanic electrocochleography (ET-Ecochg) in the differential diagnosis of AN/AD compared to the BAEP.
  
  
  METHODS
  a 4-year-old child with a diagnosis of AN/AD seen at the Audiological Research Center was submitted to ET-Ecochg with a 2000 Hz tone burst in rarefaction and condensation polarities.
  
  
  RESULTS
  the ET-Ecochg exam was illustrated. Using an appropriate protocol, it was possible to demonstrate CM and to confirm it in the Ecochg, with a recording quality superior to that obtained in the BAEP.
  
  
  CONCLUSIONS
  ET-Ecochg permitted a more detailed analysis of CM compared to the BAEP, thus showing clinical applicability for the investigation of cochlear function in AN/AD.
authors.affiliation: FMRP, USP, SP, Brazil.
authors.forename: Adriana Ribeiro Tavares
authors.initials: AR
authors.lastname: Anastasio
authors.forename: Kátia de Freitas
authors.initials: Kde F
authors.lastname: Alvarenga
authors.forename: Orozimbo Alves
authors.initials: OA
authors.lastname: Costa Filho
mesh_terms: D001308:Auditory Perceptual Disorders / Q000175:diagnosis* / Q000503:physiopathology; D002675:Child, Preschool; D003055:Cochlear Microphonic Potentials / Q000502:physiology*; D003937:Diagnosis, Differential; D004594:Electrophysiology / Q000379:methods*; D016057:Evoked Potentials, Auditory, Brain Stem / Q000502:physiology*; D005260:Female; D034381:Hearing Loss / Q000175:diagnosis*; D006801:Humans; D015203:Reproducibility of Results; D000160:Vestibulocochlear Nerve Diseases / Q000175:diagnosis* / Q000503:physiopathology