title: Quantitative analysis of electrically evoked auditory brainstem responses in implanted children with auditory neuropathy/dyssynchrony.
abstract: OBJECTIVE
  Cochlear implantation is a common treatment approach for children with auditory neuropathy/dyssynchrony (AN/AD) who do not benefit from hearing aids. The auditory brainstem response (ABR) is a measure of neural synchrony along the auditory pathway up through the brainstem. By definition, acoustically evoked ABR is absent in AN/AD, however, ABR can be elicited by electrical stimulation through the cochlear implant (electrically evoked ABR [EABR]). Reports of EABR with AN/AD to date have been primarily descriptive in nature. The objective of this study was to quantify EABR wave V measures in implanted children with and without AN/AD.
  
  
  METHODS
  Retrospective analysis of EABR waveforms from March 2000 through February 2005.
  
  
  METHODS
  Comprehensive Cochlear Implant Program/Tertiary Referral Center.
  
  
  METHODS
  Pediatric cochlear implant users of two etiologic groups: congenital AN/AD (n = 5) and other congenital profound sensorineural hearing loss (n = 27).
  
  
  METHODS
  Diagnostic.
  
  
  METHODS
  Intraoperative EABR wave V threshold, suprathreshold amplitude, and latency measures were compared between groups.
  
  
  RESULTS
  The EABR threshold and suprathreshold amplitude measures across the population were variable regardless of etiology. With some exceptions, a trend was observed for the AN/AD group that included average or below-average thresholds and below-average suprathreshold response amplitudes.
  
  
  CONCLUSIONS
  Cochlear implantation can provide synchronous neural responses to auditory stimulation in AN/AD, as previously known. The quantification of EABR measures in this study indicates that subjects with AN/AD have sufficient neural sensitivity to electrical stimulation, however, they may experience less robust neural responses at suprathreshold levels. Given the heterogeneity of potential causes of AN/AD, however, caution needs to be applied when grouping this population for analyses.
authors.affiliation: Department of Otolaryngology and Communication Sciences, Medical College of Wisconsin, Milwaukee, Wisconsin 53226, U.S.A. crunge@mcw.edu
authors.forename: Christina L
authors.initials: CL
authors.lastname: Runge-Samuelson
authors.forename: Sarah
authors.initials: S
authors.lastname: Drake
authors.forename: P Ashley
authors.initials: PA
authors.lastname: Wackym
mesh_terms: D001309:Auditory Threshold / Q000502:physiology; D002648:Child; D019929:Cochlear Implantation; D003054:Cochlear Implants; D003389:Cranial Nerve Diseases / Q000151:congenital / Q000503:physiopathology* / Q000628:therapy*; D004567:Electrodes, Implanted; D016057:Evoked Potentials, Auditory, Brain Stem / Q000502:physiology*; D006319:Hearing Loss, Sensorineural / Q000503:physiopathology; D006801:Humans; D012189:Retrospective Studies; D000160:Vestibulocochlear Nerve Diseases / Q000151:congenital / Q000503:physiopathology* / Q000628:therapy*