Fax +41 61 306 12 34 E-Mail karger@karger.ch www.karger.com Original Paper Audiol Neurotol 2009;14:163–171 DOI: 10.1159/000171478 Binaural Hearing after Cochlear Implantation in Subjects with Unilateral Sensorineural Deafness and Tinnitus Katrien Vermeire a, b Paul Van de Heyning a a University Department of Otorhinolaryngology, Head and Neck Surgery, University Hospital Antwerp, University of Antwerp, Antwerp, Belgium; b C. Doppler Laboratory for Active Implantable Systems, Institute of Ion Physics and Applied Physics, University of Innsbruck, Innsbruck, Austria Introduction Individuals who develop unilateral sensorineural hearing loss become aware of the importance of binaural hearing in everyday listening environments. They com- monly report difficulty following conversations on their deaf side, the inability to localize sounds, and difficulty understanding speech in background noise [Giolas, 1994]. Historically, the handicaps experienced by unilat- eral listeners have always been underestimated. In a 1978 report on unilateral hearing loss in children, Northern and Downs state the following: ‘Audiologists and otolar- yngologists are not usually concerned over such deafness, other than to identify its etiology and assure the parents that there will be no handicap.’ In Thorpe’s [2008] report on past and current perspectives on unilateral and mild bilateral hearing loss in children, it is shown that up to 35% of children with permanent unilateral hearing loss fail one or more grades at school. The superiority of bin- aural hearing over monaural hearing is well established in the literature [Carhart, 1965; Dirks and Wilson, 1969; MacKeith and Coles, 1971; Bronkhorst and Plomp, 1989]. Binaural hearing not only provides loudness summation but also allows use of the head shadow effect and binaural unmasking for improved speech intelligibility in noise, as well as spatial orientation and sound localization. Many of the problems of unilateral listeners result from the head shadow effect when the head is between the sound source and the good ear, attenuating the signal Key Words Unilateral sensorineural hearing loss  Cochlear implant  Speech recognition Abstract The aim of this clinical study was to assess speech recogni- tion in noise after cochlear implantation in subjects with sin- gle-sided deafness and incapacitating tinnitus. 20 subjects complaining of severe intractable tinnitus unresponsive to treatment received a MED-EL cochlear implant (CI). 11 sub- jects had normal hearing (NH group) on the contralateral side, while 9 used a hearing aid (HA group). The subjects were tested in noise in two listening conditions, i.e. with their acoustic hearing only and with adding the CI to the acoustic hearing (binaural). Subjective improvement in daily life was evaluated using the Speech Spatial and Qualities Hearing Scale (SSQ). The summation effect (3.3 dB for the HA group and 0.6 dB for the NH group) is not significant in both groups. A significant squelch effect of adding the CI was seen for the HA users (3.8 dB), but not for the NH group (1.2 dB). Additionally, a significant effect of adding the CI was found for the spatial configuration where noise is presented in front and speech on the CI side for both the HA group (6.5 dB) and the NH group (1.7 dB). Results of the SSQ show a sig- nificant overall benefit of wearing the CI for both groups. The preliminary results of these 20 subjects suggest that co- chlear implantation can improve hearing in people suffering from single-sided deafness combined with tinnitus. Copyright © 2008 S. Karger AG, Basel Received: November 28, 2007 Accepted after revision: July 30, 2008 Published online: November 13, 2008 Neurotology Audiology Katrien Vermeire, PhD University of Innsbruck, Institute of Applied Physics Technikerstrasse 25 AT–6020 Innsbruck (Austria) Tel. +43 512 507 6409, Fax +43 512 507 2922, E-Mail katrien.vermeire@uibk.ac.at © 2008 S. Karger AG, Basel 1420–3030/09/0143–0163$26.00/0 Accessible online at: www.karger.com/aud