[Verification of normative values for the Swiss version of the Freiburg speech intelligibility test]

Comprehensive analysis of two hotspot codons in the TUBB4B gene and associated phenotypes

Our purpose was to elucidate the genotype and ophthalmological and audiological phenotype in TUBB4B-associated inherited retinal dystrophy (IRD) and sensorineural hearing loss (SNHL), and to model the effects of all possible amino acid substitutions at the hotspot codons Arg390 and Arg391. Six patients from five families with heterozygous missense variants in TUBB4B were included in this observational study. Ophthalmological testing included best-corrected visual acuity, fundus examination, optical coherence tomography, fundus autofluorescence imaging, and full-field electroretinography (ERG). Audiological examination included pure-tone and speech audiometry in adult patients and auditory brainstem response testing in a child. Genetic testing was performed by disease gene panel analysis based on genome sequencing. The molecular consequences of the substitutions of residues 390 and 391 on TUBB4B and its interaction with α-tubulin were predicted in silico on its three-dimensional structure obtained by homology modelling. Two independent patients had amino acid exchanges at position 391 (p.(Arg391His) or p.(Arg391Cys)) of the TUBB4B protein. Both had a distinct IRD phenotype with peripheral round yellowish lesions with pigmented spots and mild or moderate SNHL, respectively. Yet the phenotype was milder with a sectorial pattern of bone spicules in one patient, likely due to a genetically confirmed mosaicism for p.(Arg391His). Three patients were heterozygous for an amino acid exchange at position 390 (p.(Arg390Gln) or p.(Arg390Trp)) and presented with another distinct retinal phenotype with well demarcated pericentral retinitis pigmentosa. All showed SNHL ranging from mild to severe. One additional patient showed a variant distinct from codon 390 or 391 (p.(Tyr310His)), and presented with congenital profound hearing loss and reduced responses in ERG. Variants at codon positions 390 and 391 were predicted to decrease the structural stability of TUBB4B and its complex with α-tubulin, as well as the complex affinity. In conclusion, the twofold larger reduction in heterodimer affinity exhibited by Arg391 substitutions suggested an association with the more severe retinal phenotype, compared to the substitution at Arg390.

Speech intelligibility and its relation to auditory temporal processing in Czech and Swiss German subjects with and without tinnitus

PURPOSE

Previous studies have shown that levels for 50% speech intelligibility in quiet and in noise differ for different languages. Here, we aimed to find out whether these differences may relate to different auditory processing of temporal sound features in different languages, and to determine the influence of tinnitus on speech comprehension in different languages.

METHODS

We measured speech intelligibility under various conditions (words in quiet, sentences in babble noise, interrupted sentences) along with tone detection thresholds in quiet [PTA] and in noise [PTAnoise], gap detection thresholds [GDT], and detection thresholds for frequency modulation [FMT], and compared them between Czech and Swiss subjects matched in mean age and PTA.

RESULTS

The Swiss subjects exhibited higher speech reception thresholds in quiet, higher threshold speech-to-noise ratio, and shallower slope of performance-intensity function for the words in quiet. Importantly, the intelligibility of temporally gated speech was similar in the Czech and Swiss subjects. The PTAnoise, GDT, and FMT were similar in the two groups. The Czech subjects exhibited correlations of the speech tests with GDT and FMT, which was not the case in the Swiss group. Qualitatively, the results of comparisons between the Swiss and Czech populations were not influenced by presence of subjective tinnitus.

CONCLUSION

The results support the notion of language-specific differences in speech comprehension which persists also in tinnitus subjects, and indicates different associations with the elementary measures of auditory temporal processing.

Variability in Cochlear Implantation Outcomes in a Large German Cohort With a Genetic Etiology of Hearing Loss

OBJECTIVES

The variability in outcomes of cochlear implantation is largely unexplained, and clinical factors are not sufficient for predicting performance. Genetic factors have been suggested to impact outcomes, but the clinical and genetic heterogeneity of hereditary hearing loss makes it difficult to determine and interpret postoperative performance. It is hypothesized that genetic mutations that affect the neuronal components of the cochlea and auditory pathway, targeted by the cochlear implant (CI), may lead to poor performance. A large cohort of CI recipients was studied to verify this hypothesis.

DESIGN

This study included a large German cohort of CI recipients (n = 123 implanted ears; n = 76 probands) with a definitive genetic etiology of hearing loss according to the American College of Medical Genetics (ACMG)/Association for Molecular Pathology (AMP) guidelines and documented postoperative audiological outcomes. All patients underwent preoperative clinical and audiological examinations. Postoperative CI outcome measures were based on at least 1 year of postoperative audiological follow-up for patients with postlingual hearing loss onset (>6 years) and 5 years for children with congenital or pre/perilingual hearing loss onset (≤6 years). Genetic analysis was performed based on three different methods that included single-gene screening, custom-designed hearing loss gene panel sequencing, targeting known syndromic and nonsyndromic hearing loss genes, and whole-genome sequencing.

RESULTS

The genetic diagnosis of the 76 probands in the genetic cohort involved 35 genes and 61 different clinically relevant (pathogenic, likely pathogenic) variants. With regard to implanted ears (n = 123), the six most frequently affected genes affecting nearly one-half of implanted ears were GJB2 (21%; n = 26), TMPRSS3 (7%; n = 9), MYO15A (7%; n = 8), SLC26A4 (5%; n = 6), and LOXHD1 and USH2A (each 4%; n = 5). CI recipients with pathogenic variants that influence the sensory nonneural structures performed at or above the median level of speech performance of all ears at 70% [monosyllable word recognition score in quiet at 65 decibels sound pressure level (SPL)]. When gene expression categories were compared to demographic and clinical categories (total number of compared categories: n = 30), mutations in genes expressed in the spiral ganglion emerged as a significant factor more negatively affecting cochlear implantation outcomes than all clinical parameters. An ANOVA of a reduced set of genetic and clinical categories (n = 10) identified five detrimental factors leading to poorer performance with highly significant effects ( p < 0.001), accounting for a total of 11.8% of the observed variance. The single strongest category was neural gene expression accounting for 3.1% of the variance.

CONCLUSIONS

The analysis of the relationship between the molecular genetic diagnoses of a hereditary etiology of hearing loss and cochlear implantation outcomes in a large German cohort of CI recipients revealed significant variabilities. Poor performance was observed with genetic mutations that affected the neural components of the cochlea, supporting the "spiral ganglion hypothesis."

Potentially Inadequate Real-Life Speech Levels by Healthcare Professionals during Communication with Older Inpatients

BACKGROUND

The aim of this study was to investigate real-life speech levels of health professionals during communication with older inpatients in small group settings.

METHODS

This is a prospective observational study assessing group interactions between geriatric inpatients and health professionals in a geriatric rehabilitation unit of a tertiary university hospital (Bern, Switzerland). We measured speech levels of health professionals during three typical group interactions (discharge planning meeting (n = 21), chair exercise group (n = 5), and memory training group (n = 5)) with older inpatients. Speech levels were measured using the CESVA LF010 (CESVA instruments s.l.u., Barcelona, Spain). A threshold of <60 dBA was defined as a potentially inadequate speech level.

RESULTS

Overall, mean talk time of recorded sessions was 23.2 (standard deviation 8.3) minutes. The mean proportion of talk time with potentially inadequate speech levels was 61.6% (sd 32.0%). The mean proportion of talk time with potentially inadequate speech levels was significantly higher in chair exercise groups (95.1% (sd 4.6%)) compared to discharge planning meetings (54.8% (sd 32.5%), p = 0.01) and memory training groups (56.3% (sd 25.4%), p = 0.01).

CONCLUSIONS

Our data show that real-life speech level differs between various types of group settings and suggest potentially inadequate speech levels by healthcare professionals requiring further study.

Influence of Compression Thresholds and Maximum Power Output on Speech Understanding with Bone-Anchored Hearing Systems

Bone-anchored hearing systems (BAHS) transmit sound via osseointegrated implants behind the ear. They are used to treat patients with conductive or mixed hearing loss, but speech understanding may be limited especially in users with substantial additional cochlear hearing losses. In recent years, BAHS with higher maximum power output (MPO) and more advanced digital processing including loudness compression have become available. These features may be useful to increase speech understanding in users with mixed hearing loss. We have tested the effect of 4 combinations of two different MPO levels (highest level available and level reduced by 12 dB) and two different compression thresholds (CT) levels (50 dB and 65 dB sound pressure level) in 12 adult BAHS users on speech understanding in quiet and in noise. We have found that speech understanding in quiet was not influenced significantly by any of the changes in these two fitting parameters. In contrast, in users with average bone-conduction (BC) threshold of 25 dB or more, speech understanding in noise was improved by +0.8 dB to +1.1 dB (p < 0.03) when using the higher MPO level. In this user group, there may be an additional, but very small benefit of +0.1 dB to +0.4 dB when using the lower rather than the higher CT value, but the difference was not statistically significant (p > 0.27). In users with better average BC thresholds than 25 dB, none of the improvement was statistically significant. Higher MPOs and possibly, to a lesser degree, lower CTs seem to be able to improve speech understanding in noise in users with higher BC thresholds, but even their combined effect seems to be limited.

[Audiological target parameters in clinical studies with implantable hearing systems]

A multitude of new implantable hearing systems and applications creates new options for pathologies which have been difficult to treat in the past. For many of these hearing systems preclinical technical methods to characterize devices and applications are limited. Therefore, clearly structured clinical investigations and trials are necessary to render results of devices and applications comparable for meta-analysis. Beside optimizing results in current applications, this is also essential for comparisons with established treatment options and differential indication criteria. Even during planning and design of studies, the timing of reference measurements and the choice of-on-off vs. pre-post comparisons in audiological testing decides the focus of the study. This applies equally to the choice for a monaural vs. a binaural test design, which decides whether the study will have the device or the overall result of the treatment in focus. Additional measures such as effective gain, coupling efficiency, and maximal possible intelligibility (WRS_max) can be performed with standard methods and equipment and enable better insight into functional principles of devices and applications. However, testing methods have inherent limitations that have to be taken into account for correct and meaningful interpretations. The use of standardized audiological instruments is essential and permits comparison of devices and treatment results. This is equally important for the creation of evidence-based differential indication criteria between different types of devices as well as for choosing the optimal treatment.

Using a cochlear implant processor as contralateral routing of signals device in unilateral cochlear implant recipients

Purpose

In unilateral cochlear implant (CI) recipients, a contralateral routing of signals (CROS) device enables to receive auditory information from the unaided side. This study investigates the feasibility as well as subjective and objective benefits of using a CI processor as a CROS device in unilateral CI recipients.

Methods

This is a single-center, prospective cohort study. First, we tested the directionality of the CROS processor in an acoustic chamber. Second, we examined the difference of speech perception in quiet and in noise in ten unilateral CI recipients with and without the CROS processor. Third, subjective ratings with the CROS processor were evaluated according to the Client Oriented Scale of Improvement Questionnaire.

Results

There was a time delay between the two devices of 3 ms. Connection of the CROS processor led to a summation effect of 3 dB as well as a more constant amplification along all azimuths. Speech perception in quiet showed an increased word recognition score at 50 dB (mean improvement 7%). In noise, the head shadow effect could be mitigated with significant gain in speech perception (mean improvement 8.4 dB). This advantage was reversed in unfavorable listening situations, where the CROS device considerably amplified the noise (mean:  – 4.8 dB). Subjectively, patients who did not normally wear a hearing aid on the non-CI side were satisfied with the CROS device.

Conclusions

The connection and synchronization of a CI processor as a CROS device is technically feasible and the signal processing strategies of the device can be exploited. In contra-laterally unaided patients, a subjective benefit can be achieved when wearing the CROS processor.

Correlation between Speech Perception Outcomes after Cochlear Implantation and Postoperative Acoustic and Electric Hearing Thresholds

The reliable prediction of cochlear implant (CI) speech perception outcomes is highly relevant and can facilitate the monitoring of postoperative hearing performance. To date, multiple audiometric, demographic, and surgical variables have shown some degree of correlation with CI speech perception outcomes. In the present study, postsurgical acoustic and electric hearing thresholds that are routinely assessed in clinical practice were compared to CI speech perception outcomes in order to reveal possible markers of postoperative cochlear health. A total of 237 CI recipients were included in this retrospective monocentric study. An analysis of the correlation of postoperative pure-tone averages (PTAs) and electric CI fitting thresholds (T-/C-levels) with speech perception scores for monosyllabic words in quiet was performed. Additionally, a correlation analysis was performed for postoperative acoustic thresholds in intracochlear electrocochleography (EcochG) and speech recognition scores in a smaller group (n = 14). The results show that neither postoperative acoustic hearing thresholds nor electric thresholds correlate with postoperative speech perception outcomes, and they do not serve as independent predictors of speech perception outcomes. By contrast, the postoperative intracochlear total EcochG response was significantly correlated with speech perception. Since the EcochG recordings were only performed in a small population, a large study is required to clarify the usefulness of this promising predictive parameter.

Influence of Semicircular Canal Dehiscence on Cochlear Implant Outcome

INTRODUCTION

Semicircular canal dehiscence (SCD) is defined as a defect of the bone overlying the semicircular canal. It has a relatively high prevalence of 3% in the general population, which makes it likely that a certain number of patients receiving a cochlear implant (CI) would have it. However, little is known about the influence of SCD on the CI outcome. Therefore, the aim of this study was to determine the influence of SCD on CI outcome with regard to short- and long-term word perception and hearing preservation.

METHODS

This study was a retrospective analysis of postoperative word perception ability in the electric-only condition after 6, 12, and ≥18 months and of hearing preservation 4 weeks after surgery in CI recipients with and without SCD. All patients received a preoperative 1.5- or 3-tesla magnetic resonance imaging.

RESULTS

Fifty-five patients were included. Forty-eight patients (87%) had no SCD, and 7 patients (13%) had SCD. Mean postoperative word perception scores were 66% in the non-SCD group versus 50% in the SCD group (p = 0.17) after 6 months, 74 versus 64% (p = 0.28) after 12 months, and 77 versus 73% (p = 0.62) after 18 or more months. The mean postoperative hearing loss in patients with functional residual hearing before surgery (n = 34) was 22 dB in the non-SCD group versus 31 dB in the SCD group (p = 0.15).

CONCLUSIONS

CI outcome is comparable between recipients without and with SCD. Specifically, hearing preservation rate and word perception ability in the electric-only condition seem not affected by SCD. The rate of progress of word perception ability in the first 12 months after cochlear implantation is not influenced by SCD.

Influence of maximum power output on speech understanding with bone anchored hearing systems

Background: Maximum power output (MPO) levels of bone anchored hearing systems (BAHS) vary between different devices, but are significantly lower than those of conventional hearing aids, potentially limiting speech understanding.Aims/objectives: To investigate, how MPO influences speech understanding in quiet and in noise in BAHS users.Materials and methods: 12 adult BAHS users with a bilateral conductive hearing loss and additional sensorineural hearing components between 4 and 45 dB (500-4000 Hz) participated in the study. Speech understanding was measured at 65 dB in quiet and in noise with 4 different MPO level settings, covering the approximate range of MPOs found in currently available BAHS devices.Results: Speech understanding in quiet and in noise decreased with increasing sensorineural hearing loss. MPOs levels did not influence speech understanding in quiet significantly. In contrast, speech understanding in noise was better with higher MPOs (average improvement in signal-to-noise ratio +3.2 dB, p < .001), but only if the sensorineural hearing loss component was above approximately 35 dB.Conclusions and significance: At normal conversational levels, higher MPOs have little or no influence on speech understanding in quiet with BAHS. However, they can improve speech understanding in noise for users with additional sensorineural hearing loss.

[The adaptive Freiburg monosyllabic test in noise : Development of a procedure and comparison of the results with the Oldenburg sentence test]

BACKGROUND

Whereas sentence tests are commonly performed using an adaptive procedure, this method has not yet been transferred to the Freiburg monosyllabic speech test, the most important word test. When using different procedures, a comparison of results between sentence and word tests is not possible. Therefore, an adaptive procedure which has proven itself in sentence tests was transferred to the Freiburg monosyllabic test in noise. The results of the new procedure were compared to the standard of sentence tests, i.e., the Oldenburg sentence test.

METHODS

The adaptive Freiburg monosyllabic speech test and the Oldenburg sentence test were applied in 40 otologically normal subjects in a randomized order. Results were analyzed with respect to time requirements, possible gender differences, the influence of test order, and correlation of test results.

RESULTS

The time required for the adaptive Freiburg monosyllabic speech test was significantly higher than for the Oldenburg sentence test. No significant impact of gender or test order could be shown. The mean signal-to-noise ratio for 50% speech discrimination of the Oldenburg sentence test was significantly smaller than for the adaptive Freiburg monosyllabic speech test. No correlation could be shown between the results of the two tests CONCLUSION: The Freiburg monosyllabic test can not only be used for quantifying discrimination loss in percentage terms, but also to measure the 50% speech recognition threshold with an adaptive algorithm. However, the procedure of the adaptive Freiburg monosyllabic test is more time consuming than that of the Oldenburg sentence test. Concerning a possible missing correlation between the results for 50% speech discrimination, further studies with hearing-impaired persons are needed.

Estimating the benefit of a second bone anchored hearing implant in unilaterally implanted users with a testband

Conclusion Using a second bone anchored hearing implant (BAHI) mounted on a testband in unilaterally implanted BAHI users to test its potential advantage pre-operatively under-estimates the advantage of two BAHIs placed on two implants. Objectives To investigate how well speech understanding with a second BAHI mounted on a testband approaches the benefit of bilaterally implanted BAHIs. Method Prospective study with 16 BAHI users. Eight were implanted unilaterally (group A) and eight were implanted bilaterally (group B). Aided speech understanding was measured. Speech was presented from the front and noise came either from the left, right, or from the front in two conditions for group A (with one BAHI, and with two BAHIs, where the second device was mounted on a testband) and in three conditions for group B (same two conditions as group A, and in addition with both BAHIs mounted on implants). Results Speech understanding in noise improved with the additional device for noise from the side of the first BAHI (+0.7 to +2.1 dB) and decreased for noise from the other side (-1.8 dB to -3.9 dB). Improvements were highest (+2.1 dB, p = 0.016) and disadvantages were smallest (-1.8 dB, p = 0.047) with both BAHIs mounted on implants. Testbands yielded smaller advantages and higher disadvantages of the additional BAHI (average difference = -0.9 dB).

[Testing the comparability of free-field and HDA200 headphone measurements for the Freiburg speech test]

BACKGROUND

In clinical practice, the standardized Freiburg speech test is presented via headphones as well as via loudspeakers. To achieve comparable results with both presentation modes, the headphone measurements are equated to the free-field situation. The free-field correction is determined by subjective loudness balance measurements and realized by a free-field equalizer network and a broadband frequency correction value during headphone calibration. Using the Freiburg speech test, this study tested the comparability of free-field and HDA200 headphone measurements.

PATIENTS AND METHODS

In 15 normal hearing subjects, the Freiburg speech intelligibility test was performed using both loudspeakers and HDA200 headphones.

RESULTS

The 50% speech reception threshold measured using HDA200 headphones was on average 5.1 dB lower than for loudspeakers and lay below the standardized reference values.

CONCLUSION

The desired comparability to free-field measurements could not be shown for the HDA200 headphones. The improved intelligibility via HDA200 is probably caused by the fact that the calibration correction factor of 4 dB is too high. This should be checked by the PTB.

A multilingual audiometer simulator software for training purposes

CONCLUSION

A set of algorithms, which allows a computer to determine the answers of simulated patients during pure tone and speech audiometry, is presented. Based on these algorithms, a computer program for training in audiometry was written and found to be useful for teaching purposes.

OBJECTIVES

To develop a flexible audiometer simulator software as a teaching and training tool for pure tone and speech audiometry, both with and without masking.

METHODS

First a set of algorithms, which allows a computer to determine the answers of a simulated, hearing-impaired patient, was developed. Then, the software was implemented. Extensive use was made of simple, editable text files to define all texts in the user interface and all patient definitions.

RESULTS

The software 'audiometer simulator' is available for free download. It can be used to train pure tone audiometry (both with and without masking), speech audiometry, measurement of the uncomfortable level, and simple simulation tests. Due to the use of text files, the user can alter or add patient definitions and all texts and labels shown on the screen. So far, English, French, German, and Portuguese user interfaces are available and the user can choose between German or French speech audiometry.

Speech understanding in quiet and in noise with the bone-anchored hearing aids Baha Compact and Baha Divino

CONCLUSIONS

Speech understanding is better with the Baha Divino than with the Baha Compact in competing noise from the rear. No difference was found for speech understanding in quiet. Subjectively, overall sound quality and speech understanding were rated better for the Baha Divino.

OBJECTIVES

To compare speech understanding in quiet and in noise and subjective ratings for two different bone-anchored hearing aids: the recently developed Baha Divino and the Baha Compact.

PATIENTS AND METHODS

Seven adults with bilateral conductive or mixed hearing losses who were users of a bone-anchored hearing aid were tested with the Baha Compact in quiet and in noise. Tests were repeated after 3 months of use with the Baha Divino.

RESULTS

There was no significant difference between the two types of Baha for speech understanding in quiet when tested with German numbers and monosyllabic words at presentation levels between 50 and 80 dB. For speech understanding in noise, an advantage of 2.3 dB for the Baha Divino vs the Baha Compact was found, if noise was emitted from a loudspeaker to the rear of the listener and the directional microphone noise reduction system was activated. Subjectively, the Baha Divino was rated statistically significantly better in terms of overall sound quality.