Unilateral tinnitus resulting from single-sided deafness can be treated with electrical stimulation via a CI. The outcomes of this pilot study demonstrate a new method for treatment of tinnitus in select subjects, perhaps an important new indication for cochlear implantation.

Background: While hearing aids for a contralateral routing of signals (CROS-HA) and bone conduction devices have been the traditional treatment for single-sided deafness (SSD) and asymmetric hearing loss (AHL), in recent years, cochlear implants (CIs) have increasingly become a viable treatment choice, particularly in countries where regulatory approval and reimbursement schemes are in place. Part of the reason for this shift is that the CI is the only device capable of restoring bilateral input to the auditory system and hence of possibly reinstating binaural hearing. Although several studies have independently shown that the CI is a safe and effective treatment for SSD and AHL, clinical outcome measures in those studies and across CI centers vary greatly. Only with a consistent use of defined and agreed-upon outcome measures across centers can high-level evidence be generated to assess the safety and efficacy of CIs and alternative treatments in recipients with SSD and AHL. Methods: This paper presents a comparative study design and minimum outcome measures for the assessment of current treatment options in patients with SSD/AHL. The protocol was developed, discussed, and eventually agreed upon by expert panels that convened at the 2015 APSCI conference in Beijing, China, and at the CI 2016 conference in Toronto, Canada. Results: A longitudinal study design comparing CROS-HA, BCD, and CI treatments is proposed. The recommended outcome measures include (1) speech in noise testing, using the same set of 3 spatial configurations to compare binaural benefits such as summation, squelch, and head shadow across devices; (2) localization testing, using stimuli that rove in both level and spectral content; (3) questionnaires to collect quality of life measures and the frequency of device use; and (4) questionnaires for assessing the impact of tinnitus before and after treatment, if applicable. Conclusion: A protocol for the assessment of treatment options and outcomes in recipients with SSD and AHL is presented. The proposed set of minimum outcome measures aims at harmonizing assessment methods across centers and thus at generating a growing body of high-level evidence for those treatment options.

Combined EAS in one ear supported by a hearing aid on the contralateral ear provided significantly improved speech perception compared with bilateral cochlear implantation. Although the scores for monosyllable words in quiet were higher in the bilateral CI group, the EAS group performed better in different noise and sound field conditions. Furthermore, the results indicated that binaural interaction between EAS in one ear and residual acoustic hearing in the opposite ear enhances speech perception in complex noise situations. Both bilateral CI and bimodal EAS users did not benefit from short temporal masker gaps, therefore the better performance of the EAS group in modulated noise conditions could be explained by the improved transmission of fundamental frequency cues in the lower-frequency region of acoustic hearing, which might foster the grouping of auditory objects.

Long-term HP is feasible in a subset of patients. Patients with sufficient long-term residual hearing had the prerequisite to benefit from additional acoustic stimulation. No correlation of total hearing loss with etiology, electrode design, or surgical approach was evident. Apart from individual effects of structural damage or inflammation, genetic factors are suggested to influence HP. Cases with total hearing loss still demonstrated successful speech perception in long-term monosyllable recognition scores.

Exposing patients to the risk of possible balance disorders associated with cochlear implantation is justified in view of the hearing rehabilitation achieved, even with today's broader indications for cochlear implantation. However, patients should in any case be informed about the possibility and quality of post-operative vertigo symptoms.

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.

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Although CI can cause damage to sacculus and hSCC function, this is probably not the only cause for postoperative vertigo. Advanced age is a significant risk factor for vertigo after CI.