This study compared spatial speech-in-noise performance in two cochlear implant (CI) patient groups: bimodal listeners, who use a hearing aid contralaterally to support their impaired acoustic hearing, and listeners with contralateral normal hearing, i.e., who were single-sided deaf before implantation. Using a laboratory setting that controls for head movements and that simulates spatial acoustic scenes, speech reception thresholds were measured for frontal speech-in-stationary noise from the front, the left, or the right side. Spatial release from masking (SRM) was then extracted from speech reception thresholds for monaural and binaural listening. SRM was found to be significantly lower in bimodal CI than in CI single-sided deaf listeners. Within each listener group, the SRM extracted from monaural listening did not differ from the SRM extracted from binaural listening. In contrast, a normal-hearing control group showed a significant improvement in SRM when using two ears in comparison to one. Neither CI group showed a binaural summation effect; that is, their performance was not improved by using two devices instead of the best monaural device in each spatial scenario. The results confirm a “listening with the better ear” strategy in the two CI patient groups, where patients benefited from using two ears/devices instead of one by selectively attending to the better one. Which one is the better ear, however, depends on the spatial scenario and on the individual configuration of hearing loss.

The onset of a sound receives a higher weight than later portions in time when its loudness is assessed, an effect commonly referred to as primacy effect. It is investigated if this effect can be predicted on the basis of an exponentially decaying function where the weight assigned to a temporal portion of a sound is the integral of this function over the segment duration. To test this model, temporal loudness weights were measured for sounds with different segment durations and total durations. The model successfully predicted essential aspects of the data.

Within the context of treatment with cochlear implants (CIs), different electrical and electrophysiological diagnostic procedures are applied both intra- and postoperatively. These assess electrical measures from the CI and electrophysiological measures from CI patients, respectively. The electrophysiological diagnostic procedures comprise measurement of electrically evoked compound action potentials of the auditory nerve, the registration of electrically evoked auditory brainstem potentials and the assessment of electrically evoked auditory cortical potentials. These potentials reflect auditory nerve excitation and stimulus processing in different parts of the ascending auditory pathway for intracochlear electrical stimulation via a CI. For current CIs, assessment of electrode position and examination of the implant's coupling to the auditory nerve are important domains of application for electrophysiological diagnostic procedures. Another substantial application area is the examination of stimulus processing in the auditory pathway. However, the main field of application of these procedures is supporting the fitting of CI speech processors in infants and toddlers on the basis of electrophysiological thresholds.