title: Improved outcomes in auditory brainstem implantation with the use of near-field electrical compound action potentials.
abstract: OBJECTIVE
  To compare the outcomes (auditory threshold and open-set speech perception at 48-month follow-up) of a new near-field monitoring procedure, electrical compound action potential, on positioning the auditory brainstem implant electrode array on the surface of the cochlear nuclei versus the traditional far-field electrical auditory brainstem response.
  
  
  METHODS
  Retrospective study.
  
  
  METHODS
  Tertiary referral center.
  
  
  METHODS
  Among the 202 patients with auditory brainstem implants fitted and monitored with electrical auditory brainstem response during implant fitting, 9 also underwent electrical compound action potential recording. These subjects were matched retrospectively with a control group of 9 patients in whom only the electrical auditory brainstem response was recorded. Electrical compound action potentials were obtained using a cotton-wick recording electrode located near the surface of the cochlear nuclei and on several cranial nerves.
  
  
  RESULTS
  Significantly lower potential thresholds were observed with the recording electrode located on the cochlear nuclei surface compared with the electrical auditory brainstem response (104.4 ± 32.5 vs 158.9 ± 24.2, P = .0030). Electrical brainstem response and compound action potentials identified effects on the neighboring cranial nerves on 3.2 ± 2.4 and 7.8 ± 3.2 electrodes, respectively (P = .0034). Open-set speech perception outcomes at 48-month follow-up had improved significantly in the near- versus far-field recording groups (78.9% versus 56.7%; P = .0051).
  
  
  CONCLUSIONS
  Electrical compound action potentials during auditory brainstem implantation significantly improved the definition of the potential threshold and the number of auditory and extra-auditory waves generated. It led to the best coupling between the electrode array and cochlear nuclei, significantly improving the overall open-set speech perception.
authors.affiliation: ENT Department, University of Verona, Verona, Italy.
authors.forename: Marco
authors.initials: M
authors.lastname: Mandalà
authors.affiliation: ENT Department, University of Verona, Verona, Italy.
authors.forename: Liliana
authors.initials: L
authors.lastname: Colletti
authors.affiliation: Department of Maxillo-Facial Surgery, University of Milan, Milan, Italy.
authors.forename: Giacomo
authors.initials: G
authors.lastname: Colletti
authors.affiliation: ENT Department, University of Verona, Verona, Italy vittoriocolletti@yahoo.com.
authors.forename: Vittorio
authors.initials: V
authors.lastname: Colletti
mesh_terms: D000161:Acoustic Stimulation; D000200:Action Potentials; D000328:Adult; D000368:Aged; D038263:Auditory Brain Stem Implantation / Q000379:methods*; D038262:Auditory Brain Stem Implants; D001309:Auditory Threshold / Q000502:physiology; D016022:Case-Control Studies; D004558:Electric Stimulation; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D016343:Monitoring, Intraoperative / Q000379:methods*; D058996:Quality Improvement; D012189:Retrospective Studies; D018570:Risk Assessment; D013067:Speech Perception / Q000502:physiology; D018709:Statistics, Nonparametric; D062606:Tertiary Care Centers; D013997:Time Factors; D016896:Treatment Outcome; D055815:Young Adult
keywords: auditory brainstem implant; electrical auditory brainstem response; electrical compound action potentials; intraoperative monitoring