Improvement of speech perception in quiet and in noise without decreasing localization abilities with the bone conduction device Bonebridge

The aim of this study was to examine the functional hearing results regarding speech perception and auditory sound localization in a high-resolution directional hearing setup following implantation with a new bone conduction device (MED-EL Bonebridge, Innsbruck, Austria). In addition, we assessed the patient acceptance of the Bonebridge system using a questionnaire. The study design is retrospective study. The setting is University Hospital Frankfurt. 18 patients implanted with a Bonebridge device from May 2012 to January 2015 were participated in this study. Speech perception in quiet was tested with the Freiburg monosyllable test at a presentation level of 65 dB SPL. Speech perception in noise was tested post-operatively with the Oldenburg sentence test (OLSA) in best-aided condition. We assessed auditory sound localization with a high-resolution directional hearing setup. To evaluate the acceptance by patients using the Bonebridge in daily life, we used a modified questionnaire. The overall average of functional hearing gain (n = 18) was 29.3 dB (+/- 20.7 dB). Speech perception of monosyllabic words in quiet improved by 20.7% on average, compared with the pre-operative aided condition. Mean speech reception thresholds (SRTs) of the Oldenburg sentence test (OLSA) improved significantly from -3.8 dB SNR (range -5.7 to 5.8 dB SNR) to -5.2 dB SNR (range -6.3 to -0.6 dB SNR) after implantation. Regarding localization abilities, no significant difference was found between the unaided and aided conditions following Bonebridge implantation. A survey of patients' acceptance and handling of the Bonebridge implant in daily life revealed high patient satisfaction. All patients accepted and benefited from the implanted system. No infections or adverse surgical effects occurred. Speech perception significantly improved in quiet and in noise. No significant difference in sound localization was observed. Acceptance of the Bonebridge implant, tested with a modified questionnaire, was high.