Using a cochlear implant processor as contralateral routing of signals device in unilateral cochlear implant recipients

Gawliczek, Tom; Guignard, Jérémie; Schmid, Christoph; Wimmer, Wilhelm; Caversaccio, Marco; Kompis, Martin; Weder, Stefan (2022). Using a cochlear implant processor as contralateral routing of signals device in unilateral cochlear implant recipients. European archives of oto-rhino-laryngology, 279(2), pp. 645-652. Springer 10.1007/s00405-021-06684-x

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Purpose: In unilateral cochlear implant (CI) recipients, a contralateral routing of signals (CROS) device enables to receive auditory information from the unaided side. This study investigates the feasibility as well as subjective and objective benefits of using a CI processor as a CROS device in unilateral CI recipients.

Methods: This is a single-center, prospective cohort study. First, we tested the directionality of the CROS processor in an acoustic chamber. Second, we examined the difference of speech perception in quiet and in noise in ten unilateral CI recipients with and without the CROS processor. Third, subjective ratings with the CROS processor were evaluated according to the Client Oriented Scale of Improvement Questionnaire.

Results: There was a time delay between the two devices of 3 ms. Connection of the CROS processor led to a summation effect of 3 dB as well as a more constant amplification along all azimuths. Speech perception in quiet showed an increased word recognition score at 50 dB (mean improvement 7%). In noise, the head shadow effect could be mitigated with significant gain in speech perception (mean improvement 8.4 dB). This advantage was reversed in unfavorable listening situations, where the CROS device considerably amplified the noise (mean: - 4.8 dB). Subjectively, patients who did not normally wear a hearing aid on the non-CI side were satisfied with the CROS device.

Conclusions: The connection and synchronization of a CI processor as a CROS device is technically feasible and the signal processing strategies of the device can be exploited. In contra-laterally unaided patients, a subjective benefit can be achieved when wearing the CROS processor.

Item Type:

Journal Article (Original Article)


04 Faculty of Medicine > Department of Head Organs and Neurology (DKNS) > Clinic of Ear, Nose and Throat Disorders (ENT)
10 Strategic Research Centers > ARTORG Center for Biomedical Engineering Research > ARTORG Center - Hearing Research Laboratory

Graduate School:

Graduate School for Cellular and Biomedical Sciences (GCB)

UniBE Contributor:

Gawliczek, Tom, Guignard, Jérémie, Schmid, Christoph (B), Wimmer, Wilhelm, Caversaccio, Marco, Kompis, Martin, Weder, Stefan Andreas


600 Technology > 610 Medicine & health








Wilhelm Wimmer

Date Deposited:

25 Feb 2021 11:42

Last Modified:

29 Mar 2023 23:37

Publisher DOI:


PubMed ID:





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