The population of unilateral cochlear implant (CI) users with aidable residual hearing in the contralateral ear is continuously growing. Aiding the contralateral ear with a hearing aid has been shown to provide substantial benefit regarding speech intelligibility in quiet and in noise, sound quality, localization ability and listening effort. In this study, a dedicated hearing aid with the accompanying fitting prescription, tailored to the needs of bimodal listeners was evaluated in nine bimodal CI users. Speech intelligibility scores in noise revealed on-par performance of the dedicated bimodal fitting compared to the clinical standard prescription. 78% of the bimodal CI users preferred the dedicated bimodal fitting over the clinical standard. The minimal subject-specific finetuning effort required during the dedicated bimodal fitting process emphasizes the clinical efficiency.

This study evaluated the effectiveness and usage of a smartphone application for adjusting the hearing impression of cochlear implants or hearing aids in everyday contexts. Building on previous laboratory research that demonstrated subjective auditory perception improvements through personalized settings, this research aimed to confirm these findings in real-life scenarios. Additionally, it analyzes user behavior and adaptation practices. Over a period of six months, 15 participants, including both bimodal and bilateral cochlear implant recipients, employed a self-adjustment app in their everyday lives. This application enabled them to modify the auditory experience through two distinct user interfaces and store their configurations as accessible programs. The collected data indicated that all participants were able to operate the app, and 13 of 15 participants successfully used the app throughout the whole study. In contrast to our previous findings, the acoustic environment did not affect frequency settings but did influence the choice of user interface. Bimodal users more frequently adjusted the settings for each ear independently compared to bilateral users. Most participants stated that they would also use the app outside of this study.

Smartphones are increasingly being used to enable patients to play an active role in managing their own health through applications, also called apps. The latest generation of sound processors for cochlear implants offer Bluetooth connectivity that makes it possible to connect smartphones or tablets and thus enable patients to modify their hearing sensation or measure system parameters. However, to achieve a high adoption rate and secure operation of these applications, it is necessary to design intuitive user interfaces (UI) for end users. The main goal of the current study was to evaluate the usability of two different UIs. A second goal was to compare the hearing outcomes based on the patient’s adjustments. The two different UIs were explored in a group of adult and older adult bimodal cochlear-implant users, with adjustments possible for both the cochlear implant and the contralateral hearing aid. One of the UIs comprised a classical equalizer and volume-dial approach, while the second UI followed a 2D-Surface concept, to manipulate the corresponding sound parameters. The participants changed their fitting parameters using both UIs in seven different sound scenes. The self-adjusted settings for the different scenarios were stored and recalled at a later stage for direct comparison. To enable an assessment of reliability and reproducibility, the self-adaptation was also repeated for two of the seven sound scenes. Within minutes, the participants became accustomed to the concept of both UIs and generated their own parameter settings. Both UIs resulted in settings that could be considered similar in terms of spontaneous acceptance and sound quality. Furthermore, both UIs showed high reliability in the test–retest procedure. The time required for adjustment was significantly shorter with the 2D-Surface UI. A closer look at the bimodal aspect shows that participants were able to compensate for differences in loudness and frequencies between the cochlear implant and the hearing aid. The blind comparison test showed that self-adjustment led to a higher acceptance of the sound perception in more than 80% of the cases.

Spectrotemporal modulation tests probe spectral and temporal resolution in cochlear implant (CI) users. This study investigated how carrier type and bandpass modulations influenced modulation detection performance. Nineteen CI users performed a reaction-time task involving the detection of spectral (0.25–2 cycles/octave) and/or temporal (4–16 Hz) modulations embedded in a broadband carrier. Carriers were either (1) a complex tone composed of 87 random-phase sinusoids spaced linearly at 100 Hz and weighted by a pink spectrum or (2) pink noise. Surprisingly, stimuli with dense spectral modulations were more readily detected when paired with the complex tone carrier. In contrast, the pink noise carrier yielded the expected low-pass spectral modulation transfer function profile. Electrodogram simulations based on CI sound processing strategies suggest that using a complex tone carrier with more closely spaced, logarithmically arranged tones may reduce unintended cues, such as spectral aliasing. Additionally, 2-octave limited bandwidth stimuli with a fixed temporal modulation rate (4 Hz) and spectral densities ranging from 0–2 cycles/octave were tested within broadband pink noise, centered at frequencies from 500 to 4000 Hz. Detection sensitivity was lowest at 500 Hz—a result supported by electrodograms—suggesting potential device processing limitations for spectrotemporal modulations at apical electrode sites.

Objective: The subjective experiences were assessed of cochlear implant (CI) users either wearing or not wearing a hearing aid (HA) at the contralateral ear. Design: Unilateral CI-recipients were asked to fill out a set of daily-life questionnaires on bimodal HA use, hearing disability, hearing handicap and general quality of life. Study sample: Twenty-six CI-recipients who regularly use a contralateral HA (bimodal group) and twenty-two CI-recipients who do not use a HA in the contralateral ear (unilateral group). Results: Comparisons between both groups (bimodal versus unilateral) showed no difference in self-rated disability, hearing handicap or general quality of life. However within the group of bimodal listeners, participants did report a significant benefit of bimodal hearing ability in various daily life listening situations. Conclusions: Bimodal benefit in daily life can consistently be experienced and reported within the group of bimodal users.

This study investigated a previously evaluated self-adjustment procedure with respect to its applicability for asymmetrical hearing loss (AHL). Self-adjusted settings were evaluated for speech recognition in noise and sound preference. Participants were given the possibility to adjust the left and right hearing aid separately using a two-dimensional user interface. Two different adjustment sequences were tested. Realistic everyday sound scenes in a laboratory environment were presented. The difference between the ears regarding their speech recognition in noise was tested with two spatial conditions, unaided as well as with the prescriptive formula and the self-adjusted setting. Nineteen experienced hearing aid users (median age 76 years) with different degrees of AHL were invited to participate in this study. Participants adjusted a higher gain slope across frequency in the worse ear than in the better one. The two adjustment sequences resulted in significantly different adjustment durations and gain settings. The difference between the ears regarding speech recognition in noise did not change with the self-adjustment. Overall, group-mean effect sizes were small compared to the parameter space. The adjustment procedure can be used also by hearing aid users with AHL to find a possibly preferred gain setting.