Tim Jürgens

Preferences for advanced hearing aid (HA) noise management features, such as directionality and noise reduction (DIR + NR), differ significantly among users. Due to the lack of standardized clinical guidelines for fine-tuning these features, audiologists often rely on individual user preferences. However, this approach doesn’t always ensure optimal hearing outcomes. The goal of this study was to examine how users respond to these advanced features in everyday acoustic environments, with two main goals: to assess how sensitive users are to changes in DIR + NR settings compared to subtle gain adjustments, and to identify the factors influencing DIR + NR preferences in various situations. A total of 123 individuals using bilateral HAs participated in the study, conducted at two locations in Germany and Japan. Over six testing periods (half a year), participants were provided with two listening programs that differed either in the strength of their DIR + NR settings or in gain levels for high-frequency and soft sounds. Participants documented their preferences via self-initiated questionnaires, reporting experiences with the different settings in real-life listening scenarios. Most participants preferred modest adaptive DIR + NR settings and participants generally expressed higher preference strength for small gain changes than for variations in DIR + NR. Preferences could not be reliably predicted from audiologic or environmental factors, apart from a minor influence of subjective noisiness. These findings suggest that clinicians can guide the initial fitting of DIR + NR settings to optimize speech-in-noise performance, as adaptive DIR + NR configurations are broadly acceptable. User preferences remain important, particularly during gain fine-tuning, as small adjustments can be noticeable.

The combination of directional microphones and noise reduction (DIR + NR) in hearing aids offers substantial improvement in speech intelligibility and reduction in listening effort in spatial acoustic scenarios. Pupil dilation can be used to infer ocular markers of listening effort. However, pupillometry is also known to crucially depend on luminance. The present study investigates the effects of a state-of-the-art DIR + NR algorithm (implemented in commercial hearing aids) on pupil dilation of hearing aid users both in darkness and ambient light conditions. Speech intelligibility and peak pupil dilations (PPDs) of 29 experienced hearing aid users were measured during a spatial speech-in-noise-task at a signal-to-noise ratio (SNR) matching the individual's speech reception threshold. While speech intelligibility improvements due to DIR + NR were substantial (about 35 percentage points) and independent of luminance, PPDs were only significantly reduced due to DIR + NR in ambient light, but not in darkness. This finding suggests that the reduction in PPD due to DIR + NR (most likely through improvement in SNR) is dependent on luminance and should be interpreted with caution as a marker for listening effort. Relations of reduction in PPD due to DIR + NR in ambient light to subjectively reported long-term fatigue, age, and pure-tone average were not statistically significant, which indicates that all patients benefitted similarly in listening effort from DIR + NR, irrespective of these patient-specific factors. In conclusion, careful control of luminance needs to be taken in hearing aid studies inferring listening effort from pupillometry data.

The combination of directional microphones (DIR) and spectral noise reduction (NR) is a common technique in hearing aid signal processing, for improving speech intelligibility in spatial acoustic scenarios. The benefit from DIR + NR varies considerably across individuals, which impedes prescribing the optimal strength of such processing during hearing aid fitting. The goal of this study was to investigate the correlation of four audiological factors with the benefit of speech reception thresholds (SRTs) from DIR + NR: the closedness of the acoustic coupling in the ear canal, audible contrast thresholds test (ACT™), the audiogram, and age. As part of a larger field study, 123 experienced hearing aid users in two centers in Germany and Japan were fitted bilaterally with the same hearing aids. SRTs were obtained with and without strong DIR + NR in a spatial speech-in-noise scenario before and after the field trials. Closedness of acoustic coupling was found to have the strongest correlation with SRT benefit from DIR + NR (most likely dominated by DIR rather than NR processing), followed by audible contrast thresholds (ACT) and the audiogram, both with the same significantly weaker correlation. Age was not correlated with the benefit from DIR + NR. The results suggest fitting hearing aid users irrespective of age with as-closed-as-possible acoustic coupling to maximize the benefit of DIR + NR. Furthermore, the closedness of acoustic coupling in combination with ACT or the audiogram may serve audiologists in predicting individual speech intelligibility benefits from strong DIR + NR for better guidance to set its strength during hearing aid fitting.

To describe application scenarios of a mobile device that provides a practical means for showcasing potential hearing aid benefits. A prototype of a hearing aid demonstrator based on circumaural headphones and a mobile signal processing platform was developed, providing core functions of a hearing aid, including several gain presets, in a hygienic, robust, and easy-to-use form factor. Speech intelligibility outcomes with the demonstrator and broadband level adaptations as potential fitting references were compared to outcomes with the own hearing aids of hearing-impaired participants. Furthermore, subjective assessments of the effect of the demonstrator were obtained at a public outreach event. 20 experienced hearing aid users participated in the speech intelligibility outcome measurements. 54 citizens participated in the public outreach event. Speech intelligibility measurements made with the demonstrator constituted a better predictor for typically achieved aided speech intelligibility outcomes than broadband level adaptations. Participants at the public outreach event reported that trying out the demonstrator changed their expectations of hearing aid benefits and improved their understanding of how hearing aids work. The developed demonstrator promises to be a useful tool for showcasing and probing benefits of hearing aids in clinical, public, and educational settings.

Open-source hearing aid (HA) research tools provide avenues for testing new audiological concepts. This study compared a wearable research HA (RHA) - the "Portable Hearing Laboratory" - to a high-end commercial HA (CHA) in terms of aided outcome. Using this RHA, it also evaluated a fitting approach based on non-individualised gain presets. Using a randomised repeated-measures design, participants completed speech recognition and speech quality assessments under unaided and several aided (RHA and CHA with omnidirectional and directional microphone settings) conditions. Furthermore, two approaches for prescribing amplification were evaluated with the RHA: (1) a preset approach based on non-verified clinical gain targets calculated for three standard audiograms, and (2) a best-practice approach based on individually prescribed and verified clinical gain targets. Fifteen adults aged 50-78 years with symmetrical, mild-to-moderate sensorineural hearing losses. The RHA and CHA gave similar audibility, speech recognition in quiet and in noise, and speech quality ratings in quiet and in noise. Relative to the best-practice approach, the preset approach resulted in less audibility but similar speech recognition in quiet and in noise. The RHA appears suited for testing new audiological concepts such as preset-based approaches to HA fitting.

Background: In cochlear implant (CI) treatment, there is a large variability in outcome. The aim of our study was to identify the independent audiometric measures that are most directly relevant for describing this variability in outcome characteristics of CI recipients. An extended audiometric test battery was used with selected adult patients in order to characterize the full range of CI outcomes. Methods: CI users were recruited for this study on the basis of their postoperative results and divided into three groups: low (1st quartile), moderate (medium decentile), and high hearing performance (4th quartile). Speech recognition was measured in quiet by using (i) monosyllabic words (40–80 dB SPL), (ii) speech reception threshold (SRT) for numbers, and (iii) the German matrix test in noise. In order to reconstruct demanding everyday listening situations in the clinic, the temporal characteristics of the background noise and the spatial arrangements of the signal sources were varied for tests in noise. In addition, a survey was conducted using the Speech, Spatial, and Qualities (SSQ) questionnaire and the Listening Effort (LE) questionnaire. Results: Fifteen subjects per group were examined (total N = 45), who did not differ significantly in terms of age, time after CI surgery, or CI use behavior. The groups differed mainly in the results of speech audiometry. For speech recognition, significant differences were found between the three groups for the monosyllabic tests in quiet and for the sentences in stationary (S0°N0°) and fluctuating (S0°NCI) noise. Word comprehension and sentence comprehension in quiet were both strongly correlated with the SRT in noise. This observation was also confirmed by a factor analysis. No significant differences were found between the three groups for the SSQ questionnaire and the LE questionnaire results. The results of the factor analysis indicate that speech recognition in noise provides information highly comparable to information from speech intelligibility in quiet. Conclusions: The factor analysis highlighted three components describing the postoperative outcome of CI patients. These were (i) the audiometrically measured supra-threshold speech recognition and (ii) near-threshold audibility, as well as (iii) the subjective assessment of the relationship to real life as determined by the questionnaires. These parameters appear well suited to setting up a framework for a test battery to assess CI outcomes.

Background: The Migraine Disability Assessment (MIDAS) is widely used. However, there are limited data on how much a reduction in the MIDAS score indicates a change that matters to the patient. Methods: Data from the DMKG (i.e. German Migraine and Headache Society) Headache Registry were used to determine the minimal important difference (MID) of the MIDAS, using the Patient Global Impression of Change (PGIC) as anchor and applying average change and receiver operating characteristic curve methods. Results: In total, 1218 adult migraine patients (85.6% female, 40.2 ± 12.8 years, baseline MIDAS 44.2 ± 47.4, follow-up MIDAS 36.5 ± 45.3) were included. For patients with baseline MIDAS >20 (MIDAS grade IV, n = 757), different methods using PGIC “somewhat improved” as anchor yielded percent change MIDs of the MIDAS between −29.4% and −33.2%. For baseline MIDAS between 6 and 20 (grades II and III, n = 334), using PGIC “much improved” as anchor, difference change MIDs were between −3.5 and −4.5 points. Conclusions: Based on the above results, we estimated the MID of the MIDAS at −30% for patients with a baseline MIDAS >20, and at −4 points for those with a baseline MIDAS of 6–20, for a tertiary headache care population. Trial Registration: The DMKG Headache Registry is registered with the German Clinical Trials Register (DRKS 00021081).

This study investigated sound localization abilities in patients with bilateral conductive and/or mixed hearing loss (BCHL) when listening with either one or two middle ear implants (MEIs). Sound localization was measured by asking patients to point as quickly and accurately as possible with a head-mounted LED in the perceived sound direction. Loudspeakers, positioned around the listener within a range of +73°/−73° in the horizontal plane, were not visible to the patients. Broadband (500 Hz–20 kHz) noise bursts (150 ms), roved over a 20-dB range in 10 dB steps was presented. MEIs stimulate the ipsilateral cochlea only and therefore the localization response was not affected by crosstalk. Sound localization was better with bilateral MEIs compared with the unilateral left and unilateral right conditions. Good sound localization performance was found in the bilaterally aided hearing condition in four patients. In two patients, localization abilities equaled normal hearing performance. Interestingly, in the unaided condition, when both devices were turned off, subjects could still localize the stimuli presented at the highest sound level. Comparison with data of patients implanted bilaterally with bone-conduction devices, demonstrated that localization abilities with MEIs were superior. The measurements demonstrate that patients with BCHL, using remnant binaural cues in the unaided condition, are able to process binaural cues when listening with bilateral MEIs. We conclude that implantation with two MEIs, each stimulating only the ipsilateral cochlea, without crosstalk to the contralateral cochlea, can result in good sound localization abilities, and that this topic needs further investigation.

Sound localization is an important ability in everyday life. This study investigates the influence of vision and presentation mode on auditory spatial bisection performance. Subjects were asked to identify the smaller perceived distance between three consecutive stimuli that were either presented via loudspeakers (free field) or via headphones after convolution with generic head-related impulse responses (binaural reproduction). Thirteen azimuthal sound incidence angles on a circular arc segment of ±24° at a radius of 3 m were included in three regions of space (front, rear, and laterally left). Twenty normally sighted (measured both sighted and blindfolded) and eight blind persons participated. Results showed no significant differences with respect to visual condition, but strong effects of sound direction and presentation mode. Psychometric functions were steepest in frontal space and indicated median spatial bisection thresholds of 11°–14°. Thresholds increased significantly in rear (11°–17°) and laterally left (20°–28°) space in free field. Individual pinna and torso cues, as available only in free field presentation, improved the performance of all participants compared to binaural reproduction. Especially in rear space, auditory spatial bisection thresholds were three to four times higher (i.e., poorer) using binaural reproduction than in free field. The results underline the importance of individual auditory spatial cues for spatial bisection, irrespective of access to vision, which indicates that vision may not be strictly necessary to calibrate allocentric spatial hearing.

Introduction: The amount of listening effort needed to understand speech in every-day life is an important outcome measure of the effectiveness of a hearing device. The main goal of this study was to assess subjective listening effort in patients implanted with an active middle ear implant Vibrant Soundbridge (VSB) with and without using their speech processor in complex acoustic scenarios. Methods: Ten VSB users were measured using the adaptive categorical listening effort scaling (ACALES) method in four different acoustic scenarios, realized using a multichannel loudspeaker array. The four acoustic scenarios included both spatially simple and complex speech and noise arrangements that realistically simulated challenging every-day listening situations. Signal-to-noise ratios (SNRs) were adaptively varied during the measurement. Twelve normal-hearing (NH) listeners performed the same experiment as a control group. Results: Listening effort was significantly reduced in all tested acoustic scenarios when participants used their VSB. When using the VSB, SNRs corresponding to mild-to-moderate listening effort were found not to be statistically different from SNRs found in the NH control group. SNRs corresponding to extreme listening effort of VSB users approached NH values, indicating partial restoration of listening effort. Discussion and Conclusions: Usage of the middle ear implant VSB was found to restore subjective listening effort to normal at high SNRs completely, and at lower SNRs partially. The remaining gap at low SNRs may be due to lower effectiveness of signal processing at high noise levels or due to the microphone location effect.