Stable benefits of bilateral over unilateral cochlear implantation after two years: A randomized controlled trial.
OBJECTIVE
To investigate hearing capabilities and self-reported benefits of simultaneous bilateral cochlear implantation (BiCI) compared with unilateral cochlear implantation (UCI) after a 2-year follow-up and to evaluate the learning effect of cochlear implantees over time.


METHODS
Multicenter randomized controlled trial.


METHODS
Thirty-eight postlingually deafened adults were included in this study and randomly allocated to either UCI or simultaneous BiCI. Our primary outcome was speech intelligibility in noise, with speech and noise coming from straight ahead (Utrecht-Sentence Test with Adaptive Randomized Roving levels). Secondary outcomes were speech intelligibility in noise with spatially separated sources, speech intelligibility in silence (Dutch phoneme test), localization capabilities and self-reported benefits assessed with different quality of hearing and quality of life (QoL) questionnaires. This article describes the results after 2 years of follow-up.


RESULTS
We found comparable results for the UCI and simultaneous BiCI group, when speech and noise were both presented from straight ahead. Patients in the BiCI group performed significantly better than patients in the UCI group, when speech and noise came from different directions (P = .01). Furthermore, their localization capabilities were significantly better. These results were consistent with patients' self-reported hearing capabilities, but not with the questionnaires regarding QoL. We found no significant differences on any of the subjective and objective reported outcomes between the 1-year and 2-year follow-up.


CONCLUSIONS
This study demonstrates important benefits of simultaneous BiCI compared with UCI that remain stable over time. Bilaterally implanted patients benefit significantly in difficult everyday listening situations such as when speech and noise come from different directions. Furthermore, bilaterally implanted patients are able to localize sounds, which is impossible for unilaterally implanted patients.


METHODS
1b Laryngoscope, 127:1161-1168, 2017.
Department of Otorhinolaryngology-Head and Neck Surgery, University Medical Center Utrecht, Utrecht, the Netherlands.|Brain Center Rudolf Magnus, University Medical Center Utrecht, Utrecht, the Netherlands.
Alice
http://orcid.org/0000-0001-7869-1313
A
van Zon
Department of Otorhinolaryngology-Head and Neck Surgery, University Medical Center Utrecht, Utrecht, the Netherlands.|Brain Center Rudolf Magnus, University Medical Center Utrecht, Utrecht, the Netherlands.
Yvette E
YE
Smulders
Department of Otorhinolaryngology-Head and Neck Surgery, University Medical Center Utrecht, Utrecht, the Netherlands.|Brain Center Rudolf Magnus, University Medical Center Utrecht, Utrecht, the Netherlands.
Inge
I
Stegeman
Department of Otorhinolaryngology-Head and Neck Surgery, University Medical Center Utrecht, Utrecht, the Netherlands.|Brain Center Rudolf Magnus, University Medical Center Utrecht, Utrecht, the Netherlands.
Geerte G J
GG
Ramakers
Department of Otorhinolaryngology-Head and Neck Surgery, University Medical Center Utrecht, Utrecht, the Netherlands.|Brain Center Rudolf Magnus, University Medical Center Utrecht, Utrecht, the Netherlands.
Veronique J C
VJ
Kraaijenga
Department of Otorhinolaryngology-Head and Neck Surgery, University Medical Center Utrecht, Utrecht, the Netherlands.|Brain Center Rudolf Magnus, University Medical Center Utrecht, Utrecht, the Netherlands.
Simone P C
SP
Koenraads
Department of Otorhinolaryngology-Head and Neck Surgery, University Medical Center Utrecht, Utrecht, the Netherlands.|Brain Center Rudolf Magnus, University Medical Center Utrecht, Utrecht, the Netherlands.
Gijsbert A Van
GA
Zanten
Department of Otorhinolaryngology-Head and Neck Surgery, University Medical Center Utrecht, Utrecht, the Netherlands.
Albert B
AB
Rinia
Department of Otorhinolaryngology-Head and Neck Surgery, Maastricht University Medical Center, Maastricht, the Netherlands.
Robert J
RJ
Stokroos
Department of Otorhinolaryngology, University Medical Center Groningen, Groningen, the Netherlands.|Graduate School of Medical Sciences, Research School of Behavioural and Cognitive Neurosciences, University Medical Center Groningen, Groningen, the Netherlands.
Rolien H
RH
Free
Department of Otorhinolaryngology-Head and Neck Surgery, Leiden University Medical Center, Leiden, the Netherlands.|Leiden Institute for Brain and Cognition, Leiden University Medical Center, Leiden, the Netherlands.
Johan H M
JH
Frijns
Department of Otorhinolaryngology-Head and Neck Surgery, Radboud University Medical Center, Nijmegen, the Netherlands.|Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, Nijmegen, the Netherlands.
Wendy J
WJ
Huinck
Department of Otorhinolaryngology-Head and Neck Surgery, Radboud University Medical Center, Nijmegen, the Netherlands.|Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, Nijmegen, the Netherlands.
Emmanuel A M
EA
Mylanus
Department of Otorhinolaryngology-Head and Neck Surgery, University Medical Center Utrecht, Utrecht, the Netherlands.|Brain Center Rudolf Magnus, University Medical Center Utrecht, Utrecht, the Netherlands.
Rinze A
RA
Tange
Department of Otorhinolaryngology-Head and Neck Surgery, University Medical Center Utrecht, Utrecht, the Netherlands.|Brain Center Rudolf Magnus, University Medical Center Utrecht, Utrecht, the Netherlands.
Adriana L
AL
Smit
Department of Otorhinolaryngology-Head and Neck Surgery, University Medical Center Utrecht, Utrecht, the Netherlands.|Brain Center Rudolf Magnus, University Medical Center Utrecht, Utrecht, the Netherlands.
Hans G X M
HG
Thomeer
Department of Otorhinolaryngology-Head and Neck Surgery, University Medical Center Utrecht, Utrecht, the Netherlands.|Brain Center Rudolf Magnus, University Medical Center Utrecht, Utrecht, the Netherlands.
Vedat
V
Topsakal
Department of Otorhinolaryngology-Head and Neck Surgery, University Medical Center Utrecht, Utrecht, the Netherlands.|Brain Center Rudolf Magnus, University Medical Center Utrecht, Utrecht, the Netherlands.
Wilko
W
Grolman
D000328:Adult; D000368:Aged; D019929:Cochlear Implantation / Q000379:methods*; D003054:Cochlear Implants; D005260:Female; D006312:Hearing Loss, Bilateral / Q000601:surgery; D006319:Hearing Loss, Sensorineural / Q000601:surgery*; D006801:Humans; D008297:Male; D008875:Middle Aged; D011788:Quality of Life; D013065:Speech Intelligibility; D011795:Surveys and Questionnaires; D016896:Treatment Outcome
Cochlear implants; cochlear implantation; deafness; hearing aids; hearing loss; sound localization