title: Results from a European clinical investigation of the Nucleus multichannel auditory brainstem implant.
abstract: OBJECTIVE
  This study was designed to investigate the perceptual benefits and potential risks of implanting the Nucleus(R) multichannel auditory brainstem implant.
  
  
  METHODS
  Between September 1992 and October 1997 a total of 27 subjects received a Nucleus 20- or 21-channel Auditory Brainstem Implant (ABI). All subjects involved in the trial had bilateral acoustic tumour as a result of neurofibromatosis type 2 (NF2) resulting in complete dysfunction of the VIIIth nerve. The study used each subject as their own control without a preoperative baseline because residual hearing, if existing, was destroyed at surgery by tumour removal. A battery of speech tests was conducted to evaluate each patient's performance and communication abilities. Tests were conducted, where possible, in the auditory-only, visual-only, and auditory-visual conditions at 3 days postoperatively (baseline), at 3-mo intervals for the first year and every 12 mo thereafter. A subjective performance questionnaire was administered together with an extensive neurological examination at each test interval.
  
  
  RESULTS
  27 subjects involved in this trial were successfully implanted with a Nucleus ABI. One subject died 2 days postoperatively due to a lung embolism unrelated to the device. Twenty-six subjects underwent device activation and all but one patient received auditory sensation at initial stimulation (96.2%). On average 8.6 (+/-4.2) of the available 21 electrodes were used in the patients' MAPs. Performance evaluation measures showed that the majority of users had access to auditory information such as environmental sound awareness together with stress and rhythm cues in speech that assist with lipreading. Although most subjects did not achieve any functional auditory-alone, open-set speech understanding, two subjects from this series (7.4%) did receive sufficient benefit to be able to use the ABI in conversation without lipreading.
  
  
  CONCLUSIONS
  Although the medical risks and surgical complexity associated with ABI device implantation are far greater than those for a cochlear implant, the clinical results from this trial show that the Nucleus multichannel ABI is capable of providing a significant patient benefit over risk ratio for subjects suffering loss of hearing due to bilateral retrocochlear lesions.
authors.affiliation: Cochlear Europe Ltd., 22-24 Worple Road, Wimbledon, London SW19 4DF, UK.
authors.forename: Barry
authors.initials: B
authors.lastname: Nevison
authors.forename: Roland
authors.initials: R
authors.lastname: Laszig
authors.forename: Wolf-Peter
authors.initials: WP
authors.lastname: Sollmann
authors.forename: Thomas
authors.initials: T
authors.lastname: Lenarz
authors.forename: Olivier
authors.initials: O
authors.lastname: Sterkers
authors.forename: Richard
authors.initials: R
authors.lastname: Ramsden
authors.forename: Bernard
authors.initials: B
authors.lastname: Fraysse
authors.forename: Manuel
authors.initials: M
authors.lastname: Manrique
authors.forename: Helge
authors.initials: H
authors.lastname: Rask-Andersen
authors.forename: Emilio
authors.initials: E
authors.lastname: Garcia-Ibanez
authors.forename: Vittorio
authors.initials: V
authors.lastname: Colletti
authors.forename: Ernst
authors.initials: E
authors.lastname: von Wallenberg
mesh_terms: D000161:Acoustic Stimulation / Q000295:instrumentation*; D000293:Adolescent; D000328:Adult; D001933:Brain Stem / Q000601:surgery*; D003056:Cochlear Nerve / Q000503:physiopathology; D003638:Deafness / Q000209:etiology / Q000503:physiopathology / Q000601:surgery*; D004867:Equipment Design; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D016518:Neurofibromatosis 2 / Q000150:complications; D017060:Patient Satisfaction; D019736:Prostheses and Implants; D011795:Surveys and Questionnaires; D016896:Treatment Outcome