Objective: To evaluate speech performance, in quiet and noise, and localization ability in adult patients who had undergone bilateral and simultaneous implantation. Study Design: 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° to +90° 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 ≥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 ≥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. Conclusion: 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.

1.
Buss E, Pillsbury HC, Buchman CA, Pillsbury CH, Clark MS, Haynes DS, Labadie RF, Amberg S, Roland PS, Kruger P, Novak MA, Wirth JA, Black JM, Peters R, Lake J, Wackym PA, Firszt JB, Wilson BS, Lawson DT, Schatzer R, D’Haese PS, Barco AL: Multicenter US bilateral MED-EL cochlear implantation study: speech perception over the first year of use. Ear Hear 2008;29:20–32.
2.
Gantz BJ, Tyler RS, Rubinstein JT, Wolaver A, Lowder M, Abbas P, Brown C, Hughes M, Preece JP: Binaural cochlear implants placed during the same operation. Otol Neurotol 2002;23:169–180.
3.
Grantham W, Ashmead DH, Ricketts TA, Labadie RF, Haynes DS: Horizontal-plane localization in noise and speech signals by postlingually deafened adults fitted with bilateral cochlear implants. Ear Hear 2007;28:524–541.
4.
Laszig R, Aschendorff A, Stecker M, Müller-Deile J, Maune S, et al: Benefits of bilateral electrical stimulation with the nucleus cochlear implants in adults: 6-month postoperative results. Otol Neurotol 2004;25:958–968.
5.
Litovsky RY, Parkinson A, Arcaroli J, Peters R, Lake J, Johnstone P, Yu G: Bilateral cochlear implants in adults and children. Arch Otolaryngol Head Neck Surg 2004;130:648–655.
6.
Litovsky RY, Parkinson A, Arcaroli J, Sammeth C: Simultaneous bilateral cochlear implantation in adults: a multicenter clinical study. Ear Hear 2006;27:714–731.
7.
Müller J, Schön F, Helms J: Speech understanding in quiet and noise in bilateral users of the MED-EL Combi 40/40+ cochlear implant system. Ear Hear 2002;23:198–206.
8.
Murphy J, O’Donoghue G: Bilateral cochlear implantation: an evidence-based medicine evaluation. Laryngoscope 2007;117:1412–1418.
9.
Neuman AC, Haravon A, Sislian N, Waltzman SB: Sound-direction identification with bilateral cochlear implants. Ear Hear 2007;28:73–82.
10.
Nopp P, Schleich P, D’Haese P: Sound localization in bilateral users of MED-EL COMBI 40/40+ cochlear implants. Ear Hear 2004;25:205–214.
11.
Ramsden R, Greenham P, O’Driscoll M, Mawman D, Proops D, Craddock L, Fielden C, Graham J, Meerton L, Verschuur C, Toner J, McAnallen C, Osborne J, Doran M, Gray R, Pickerill M: Evaluation of bilaterally implanted adult subjects with the nucleus 24 cochlear implant system. Otol Neurotol 2005;26:988–998.
12.
Ricketts TA, Grantham DW, Ashmead DH, Haynes DS, Labadie RF: Speech recognition for unilateral and bilateral cochlear implant modes in the presence of uncorrelated noise sources. Ear Hear 2006;27:763–773.
13.
Schleich P, Nopp P, D’Haese P: Head shadow, squelch and summation effects in bilateral users of the MED-EL Combi 40/40+ cochlear implant. Ear Hear 2004;25:197–204.
14.
Schoen F, Mueller J, Helms J, Nopp P: Sound localization and sensitivity to interaural cues in bilateral users of the Med-El Combi 40/40+ cochlear implant system. Otol Neurotol 2005;26:429–437.
15.
Schön F, Müller J, Helms J: Speech reception threshold obtained in a symmetrical four-loudspeaker arrangement from bilateral users of MED-EL cochlear implants. Otol Neurotol 2002;23:710–714.
16.
Summerfield AQ, Barton GR, Toner J, McAnallen C, Proops P, Harries C, Cooper H, Court I, Gray R, Osborne J, Doran M, Ramdsen R, Mawman D, O’Driscoll M, Graham J, Aleksy W, Meerton L, Verschure C, Ashcroft P, Pringle M: Self-reported benefits from successive bilateral cochlear implantation in post-lingually deafened adults: randomised controlled trial. Int J Audiol 2006;45:S99–S107.
17.
Tyler RS, Gantz BJ, Rubinstein JT, Wilson BS, Parkinson AJ, Wolaver A, Preece JP, Witt S, Lowder MW: Three-month results with bilateral cochlear implants. Ear Hear 2002;23:80S–89S.
18.
Verschuur CA, Lutman ME, Ramsden R, Greenham P, O’Driscoll M: Auditory localization abilities in bilateral cochlear implant recipients. Otol Neurotol 2005;26:965–971.
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