title: Performance with the 20 + 2L lateral wall cochlear implant.
abstract: OBJECTIVE
  The purpose of this study was to investigate the operating characteristics of the Nucleus 20 + 2L lateral wall cochlear implant including speech recognition results.
  
  
  METHODS
  This was a prospective randomized study involving five different modes of stimulation.
  
  
  METHODS
  This study was carried out in an academic, tertiary referral center.
  
  
  METHODS
  The patients included in this study were adult cochlear implant candidates ages 44-74 years. Length of deafness ranged from 1 to 58 years with a variety of etiologies.
  
  
  METHODS
  All patients were implanted with a 20 + 2L implant, which includes an intrascalar electrode array and an apically placed extracochlear, titanium encased ball electrode in contact with the endosteum of the apical turn. All patients underwent psychophysical and speech recognition testing in five different modes of electrode configuration.
  
  
  METHODS
  The main outcome measures included thresholds, comfort levels, dynamic ranges, and speech recognition results obtained in five electrode configuration modes.
  
  
  RESULTS
  Thresholds were significantly lower (repeated measures ANOVA) in both monopolar conditions when compared to bipolar mode of stimulation. A binomial statistical analysis indicated that in five of nine patients activated in all five modes of stimulation, the monopolar modes of stimulation resulted in improved speech recognition scores.
  
  
  CONCLUSIONS
  The results of the study demonstrate the feasibility of the use of an apical lateral cochlear wall electrode in conjunction with an intrascalar electrode array. It further demonstrated the superiority of monopolar stimulation in selected patients.
authors.affiliation: Department of Otolaryngology, University of Michigan Medical School, Ann Arbor 48109-0312, USA.
authors.forename: P R
authors.initials: PR
authors.lastname: Kileny
authors.forename: T A
authors.initials: TA
authors.lastname: Zwolan
authors.forename: S A
authors.initials: SA
authors.lastname: Telian
authors.forename: A
authors.initials: A
authors.lastname: Boerst
mesh_terms: D000328:Adult; D000368:Aged; D000704:Analysis of Variance; D019929:Cochlear Implantation / Q000295:instrumentation*; D003638:Deafness / Q000601:surgery*; D004867:Equipment Design; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010700:Phonetics; D011446:Prospective Studies; D011601:Psychophysics; D013067:Speech Perception / Q000502:physiology*; D013069:Speech Reception Threshold Test