title: Speech performance and sound localization in a complex noisy environment in bilaterally implanted adult patients.
abstract: OBJECTIVE
  To evaluate speech performance, in quiet and noise, and localization ability in adult patients who had undergone bilateral and simultaneous implantation.
  
  
  METHODS
  Prospective multi-center study.
  
  
  METHODS
  Twenty-seven adult patients with profound or total hearing loss were bilaterally implanted in a single-stage procedure, and simultaneously activated (Med-El, Combi 40/40+). Subjects were assessed before implantation and at 3, 6 and 12 months after switch-on. Speech perception tests in monaural and binaural conditions were performed in quiet and in noise using disyllabic words, with speech coming from the front and a cocktail party background noise coming from 5 loudspeakers. Sound localization measurements were also performed in background noise coming from 5 loudspeakers positioned from -90 degrees to +90 degrees azimuth in the horizontal plane, and using a speech stimulus.
  
  
  RESULTS
  There was a bilateral advantage at 12 months in quiet (77 +/- 5.0% in bilateral condition, 67 +/- 5.3% for the better ear, p < 0.005) and in noise (signal-to-noise ratio +15 dB: 63 +/- 5.9% in bilateral condition, 55 +/- 6.9% for the better ear, p < 0.05). Considering unilateral speech scores recorded in quiet at 12 months, subjects were categorized as 'good performers' (speech comprehension score > or =60% for the better ear, n = 19) and 'poor performers' (n = 8). Subjects were also categorized as 'asymmetrical' (difference between their 2 unilateral speech scores > or =20%, n = 11) or 'symmetrical' (n = 16). The largest advantage (bilateral compared to the better ear) was obtained in poor performers: +19% compared to +7% in good performers (p < 0.05). In the group of good performers, there was a bilateral advantage only in cases of symmetrical results between the 2 ears (n = 10). In the group of poor performers, the bilateral advantage was shown in both patients with symmetrical (n = 6) and asymmetrical results (n = 2). In bilateral conditions, the sound localization ability in noise was improved compared to monaural conditions in patients with symmetrical and asymmetrical performance between the 2 ears. No preoperative factor (age, duration of deafness, use of hearing aids, etiology, etc.) could predict the asymmetrical performance, nor which ear would be the best.
  
  
  CONCLUSIONS
  This study demonstrates a bilateral advantage (at 12 months after the implantation) in speech intelligibility and sound localization in a complex noisy environment. In quiet, this bilateral advantage is shown in cases of poor performance of both ears, and in cases of good performance with symmetrical results between the 2 ears. No preoperative factor can predict the best candidates for a simultaneous bilateral implantation.
authors.affiliation: AP-HP, Hôpital Beaujon, Service d'ORL, Clichy, France. isabelle.mosnier@lmr.aphp.fr
authors.forename: Isabelle
authors.initials: I
authors.lastname: Mosnier
authors.forename: Olivier
authors.initials: O
authors.lastname: Sterkers
authors.forename: Jean-Pierre
authors.initials: JP
authors.lastname: Bebear
authors.forename: Benoit
authors.initials: B
authors.lastname: Godey
authors.forename: Alain
authors.initials: A
authors.lastname: Robier
authors.forename: Olivier
authors.initials: O
authors.lastname: Deguine
authors.forename: Bernard
authors.initials: B
authors.lastname: Fraysse
authors.forename: Philippe
authors.initials: P
authors.lastname: Bordure
authors.forename: Michel
authors.initials: M
authors.lastname: Mondain
authors.forename: Didier
authors.initials: D
authors.lastname: Bouccara
authors.forename: Alexis
authors.initials: A
authors.lastname: Bozorg-Grayeli
authors.forename: Stéphanie
authors.initials: S
authors.lastname: Borel
authors.forename: Emmanuèle
authors.initials: E
authors.lastname: Ambert-Dahan
authors.forename: Evelyne
authors.initials: E
authors.lastname: Ferrary
mesh_terms: D000328:Adult; D000368:Aged; D003054:Cochlear Implants; D006312:Hearing Loss, Bilateral / Q000628:therapy*; D006801:Humans; D008875:Middle Aged; D009622:Noise; D011379:Prognosis; D013017:Sound Localization; D013067:Speech Perception; D016896:Treatment Outcome; D055815:Young Adult