Benefits of a contralateral routing of signal device for unilateral Naída CI cochlear implant recipients

  • Isabelle MosnierEmail author
  • Ghizlene Lahlou
  • Jonathan Flament
  • Nathalie Mathias
  • Evelyne Ferrary
  • Olivier Sterkers
  • Daniele Bernardeschi
  • Yann Nguyen



Many bilaterally deaf adults are only able to receive one cochlear implant (CI), resulting in suboptimal listening performance, especially in challenging listening environments. Adding a contralateral routing of signal (CROS) device to a unilateral CI is one possibility to alleviate these challenges. This study examined the benefit of such a CROS device.


Thirteen adult subjects with at least 6 months of CI use, and no or limited benefit of a hearing instrument in the contralateral ear were included in the study. The perceived benefit of a CROS device in everyday listening environments was evaluated up to 1 year after initial fitting using several questionnaires. Speech intelligibility performance was determined using the French matrix sentence test in quiet and in two speech-in-noise setups and was followed for 3 months after CROS fitting.


Subjects indicated high satisfaction with the practical usability of the CROS device and long-term device retention was high. Perceived benefits in everyday listening environments were reported. Formal speech intelligibility tests revealed statistically significant median improvements of 6.93 dB SPL (Wilcoxon Z = 2.380, p = 0.017) in quiet and up to 8.00 dB SNR (Wilcoxon Z = 2.366, p = 0.018) in noise. These benefits were accessible immediately without a need for prolonged acclimatization.


Subjective satisfaction and device retention as well as speech intelligibility benefits in quiet and in noise prove the CROS device to be a valuable addition to a unilateral CI in cases of bilateral deafness where bilateral implantation is not an option.


Cochlear implantation CROS Binaurality Speech intelligibility Subjective benefit 


Compliance with ethical standards

Conflict of interest

The authors declare that they have no conflict of interest.

Ethical approval

All study procedures were approved by the ethical committee, ‘Comité de Protection des Personnes Sud-Est V’ and the French competent authority, ANSM (Agence Nationale de Sécurité du Médicament et des produits de santé) and were conducted in accordance with the ethical standards defined by the Declaration of Helsinki. The study was registered as N° NCT03078920 at

Informed consent

Informed consent was obtained from all individual participants included in the study.

Supplementary material

405_2019_5467_MOESM1_ESM.pdf (616 kb)
Supplementary file1 (PDF 615 kb)
405_2019_5467_MOESM2_ESM.pdf (631 kb)
Supplementary file2 (PDF 630 kb)


  1. 1.
    De Seta D, Nguyen Y, Vanier A et al (2016) Five-year hearing outcomes in bilateral simultaneously cochlear-implanted adult patients. Audiol Neurootol 21:261–267. CrossRefGoogle Scholar
  2. 2.
    Laske RD, Veraguth D, Dillier N et al (2009) Subjective and objective results after bilateral cochlear implantation in adults. Otol Neurotol Off Publ Am Otol Soc Am Neurotol Soc Eur Acad Otol Neurotol 30:313–318. CrossRefGoogle Scholar
  3. 3.
    Mosnier I, Sterkers O, Bebear J-P et al (2009) Speech performance and sound localization in a complex noisy environment in bilaterally implanted adult patients. Audiol Neurootol 14:106–114. CrossRefGoogle Scholar
  4. 4.
    Smulders YE, van Zon A, Stegeman I et al (2016) Comparison of bilateral and unilateral cochlear implantation in adults: a randomized clinical trial. JAMA Otolaryngol Head Neck Surg 142:249–256. CrossRefGoogle Scholar
  5. 5.
    van Schoonhoven J, Sparreboom M, van Zanten BGA et al (2013) The effectiveness of bilateral cochlear implants for severe-to-profound deafness in adults: a systematic review. Otol Neurotol 34:190–198CrossRefGoogle Scholar
  6. 6.
    Chen JM, Amoodi H, Mittmann N (2014) Cost-utility analysis of bilateral cochlear implantation in adults: a health economic assessment from the perspective of a publicly funded program. Laryngoscope 124:1452–1458. CrossRefGoogle Scholar
  7. 7.
    Crathorne L, Bond M, Cooper C et al (2012) A systematic review of the effectiveness and cost-effectiveness of bilateral multichannel cochlear implants in adults with severe-to-profound hearing loss. Clin Otolaryngol 37:342–354. CrossRefGoogle Scholar
  8. 8.
    Ryu N-G, Moon IJ, Byun H et al (2015) Clinical effectiveness of wireless CROS (contralateral routing of offside signals) hearing aids. Eur Arch Otorhinolaryngol 272:2213–2219. CrossRefGoogle Scholar
  9. 9.
    Arora R, Amoodi H, Stewart S et al (2013) The addition of a contralateral routing of signals microphone to a unilateral cochlear implant system. A prospective study in speech outcomes. Laryngoscope 123:746–751. CrossRefGoogle Scholar
  10. 10.
    Grewal AS, Kuthubutheen J, Smilsky K et al (2015) The role of a new contralateral routing of signal microphone in established unilateral cochlear implant recipients. Laryngoscope 125:197–202. CrossRefGoogle Scholar
  11. 11.
    Guevara N, Grech C, Gahide I, Gallego S (2015) Assessment of the contralateral routing of signal system in unilateral cochlear implantation. Clin Otolaryngol 40:535–544. CrossRefGoogle Scholar
  12. 12.
    Taal CH, van Barneveld DCPBM, Soede W et al (2016) Benefit of contralateral routing of signals for unilateral cochlear implant users. J Acoust Soc Am 140:393. CrossRefGoogle Scholar
  13. 13.
    van Loon MC, Goverts ST, Merkus P et al (2014) The addition of a contralateral microphone for unilateral cochlear implant users: not an alternative for bilateral cochlear implantation. Otol Neurotol Off Publ Am Otol Soc Am Neurotol Soc Eur Acad Otol Neurotol 35:e233–e239. CrossRefGoogle Scholar
  14. 14.
    Weder S, Kompis M, Caversaccio M, Stieger C (2015) Benefit of a contralateral routing of signal device for unilateral cochlear implant users. Audiol Neurootol 20:73–80. CrossRefGoogle Scholar
  15. 15.
    Wimmer W, Kompis M, Stieger C et al (2017) Directional microphone contralateral routing of signals in cochlear implant users: a within-subjects comparison. Ear Hear 38:368–373. CrossRefGoogle Scholar
  16. 16.
    Dwyer RT, Kessler D, Butera IM, Gifford RH (2018) Contralateral routing of signal yields significant speech in noise benefit for unilateral cochlear implant recipients. J Am Acad Audiol. Google Scholar
  17. 17.
    Ernst A, Baumgärtel RM, Diez A, Battmer R-D (2019) Evaluation of a wireless contralateral routing of signal (CROS) device with the Advanced Bionics Naída CI Q90 sound processor. Cochlear Implants Int. Google Scholar
  18. 18.
    Snapp HA, Hoffer ME, Spahr A, Rajguru SM (2018) Application of wireless contralateral routing of signal in unilateral cochlear implant users with bilateral profound hearing loss. J Am Acad Audiol. Google Scholar
  19. 19.
    Cox RM, Alexander GC (1995) The abbreviated profile of hearing aid benefit. Ear Hear 16:176–186CrossRefGoogle Scholar
  20. 20.
    Noble W, Jensen NS, Naylor G et al (2013) A short form of the speech, spatial and qualities of hearing scale suitable for clinical use: the SSQ12. Int J Audiol 52:409–412. CrossRefGoogle Scholar
  21. 21.
    Gatehouse S, Noble W (2004) The speech, spatial and qualities of hearing scale (SSQ). Int J Audiol 43:85–99CrossRefGoogle Scholar
  22. 22.
    Schafer EC, Baldus N, D’Souza M et al (2013) Behavioral and subjective performance with digital CROS/BiCROS hearing instruments. J Acad Rehabil Audiol 46:62–93Google Scholar
  23. 23.
    Jansen S, Luts H, Wagener KC et al (2012) Comparison of three types of French speech-in-noise tests: a multi-center study. Int J Audiol 51:164–173. CrossRefGoogle Scholar
  24. 24.
    Wagener K, Kühnel V, Kollmeier B (1999) Entwicklung und Evaluation eines Satztests für die deutsche Sprache I: Design des Oldenburger Satztests. Zeitschrift Für Audiologie/Audiological Acoustics 38:4–15Google Scholar
  25. 25.
    Schlueter A, Lemke U, Kollmeier B, Holube I (2016) Normal and time-compressed speech: how does learning affect speech recognition thresholds in noise? Trends Hear. Google Scholar

Copyright information

© Springer-Verlag GmbH Germany, part of Springer Nature 2019

Authors and Affiliations

  1. 1.Sorbonne Université, Inserm, Unité de Réhabilitation chirurgicale mini-invasive robotisée de l’auditionParisFrance
  2. 2.AP-HP, GHU Pitié-Salpêtrière, Service ORL, Otologie, Implants auditifs et chirurgie de la base du crâneParisFrance
  3. 3.Sorbonne Université, Institut Pasteur, Inserm, Unité de génétique et de physiologie de l’AuditionParisFrance
  4. 4.Laboratoire AudikaParisFrance
  5. 5.Advanced BionicsBronFrance
  6. 6.Unité Otologie, Implants auditifs et Chirurgie de la base du crâne, GH Pitié-Salpêtrière-Bâtiment CastaigneParis Cedex 13France

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