[Check of hearing aid fitting]

[Extended preoperative speech audiometric diagnostics for cochlear implant treatment]

BACKGROUND

For severe hearing loss and even profound deafness, cochlear implants (CIs) have become the treatment of choice. For establishment of the CI indication, the preoperative Freiburger monosyllabic word recognition (EV) at 65 dB SPL in free field with a hearing aid (EVHG65) and the maximal understanding (mEV) without a hearing aid with headphones results are important. The goal of this retrospective study was to analyse the correlation of word recognition with a hearing aid at 80 dB SPL (EVHG80) and mEV. This represents an extension to measuring EVHG65 compared to mEV and to pure-tone audiometry (4FPTA).

METHODS

In this study, word recognition with and without a hearing aid was retrospectively analysed for 661 ears. Inclusion criterium was CI implantation at a later date.

RESULTS

During preoperative CI diagnostics, an mEV of 0% was found in 334 ears. The EVHG65 for 485 ears and the EVHG80 for 335 ears were also 0%. The EV with hearing aid was found to worsen with increasing 4FPTA at both sound pressure levels, although this effect was smaller at 80 dB SPL than at 65 dB SPL. Including only ears with mEV > 0 % (N = 260 ears), a stronger correlation between EVHG80 and mEV with a difference of (-4.0 ± 16.4%) in comparison to EVHG65 and mEV with a difference of (-18.3 ± 16.7%) is seen. This shows a significant difference between mEV and EVHG80 compared to mEV and EVHG65.

CONCLUSION

At a sound pressure level of 65 dB SPL, EV with hearing aid often does not show the accordance with mEV specified by hearing aid and CI guidelines. The EVHG80 correlates better with mEV than EVHG65. For clinical diagnosis it is rational to measure speech discrimination with hearing aid at levels higher than 65 dB SPL.

Validation of a predictive model for speech discrimination after cochlear impIant provision

BACKGROUND

If sufficient speech discrimination is no longer achieved with conventional hearing systems, an audiological indication for a cochlear implant (CI) is given. However, there are no established target criteria for CI aftercare with regard to the level of speech comprehension to be achieved. The aim of this study is to validate an existing predictive model for speech comprehension after CI provision. This is applied to different patient groups.

MATERIALS AND METHODS

The prospective study included 124 postlingually deaf adults. The model is based on preoperative maximum monosyllabic recognition score, aided monosyllabic recognition score at 65 dBSPL, and age the time of implantation. The model was investigated with regard to prediction accuracy for monosyllabic recognition with CI after 6 months.

RESULTS

Mean speech discrimination improved from 10% with hearing aid to 65% with CI after 6 months, with a statistically significant improvement in 93% of cases. Deterioration of aided unilateral speech discrimination was not observed. The mean prediction error was 11.5 percentage points in the cases with preoperative scores better than zero and 23.2 percentage points in all other cases.

CONCLUSION

Cochlear implantation should also be considered in patients with moderately severe to severe hearing loss and insufficient speech discrimination with hearing aids. The model based on preoperatively measured data for predicting speech discrimination with CI can be used in preoperative consultation and in the context of postoperative quality assurance.

[Validation of a predictive model for speech discrimination after cochlear implant provision]

BACKGROUND

If sufficient speech discrimination is no longer achieved with conventional hearing systems, an audiological indication for a cochlear implant (CI) is given. However, there are no established target criteria for CI aftercare with regard to the level of speech comprehension to be achieved. The aim of this study is to validate an existing predictive model for speech comprehension after CI provision. This is applied to different patient groups.

MATERIALS AND METHODS

The prospective study included 124 postlingually deaf adults. The model is based on preoperative maximum monosyllabic recognition score, aided monosyllabic recognition score at 65 dB_SPL, and age the time of implantation. The model was investigated with regard to prediction accuracy for monosyllabic recognition with CI after 6 months.

RESULTS

Mean speech discrimination improved from 10% with hearing aid to 65% with CI after 6 months, with a statistically significant improvement in 93% of cases. Deterioration of aided unilateral speech discrimination was not observed. The mean prediction error was 11.5 percentage points in the cases with preoperative scores better than zero and 23.2 percentage points in all other cases.

CONCLUSION

Cochlear implantation should also be considered in patients with moderately severe to severe hearing loss and insufficient speech discrimination with hearing aids. The model based on preoperatively measured data for predicting speech discrimination with CI can be used in preoperative consultation and in the context of postoperative quality assurance.

Wirksamkeit der Hörgeräteversorgung bei hochgradigem Hörverlust

Hintergrund

In der Praxis liegt das unilaterale Einsilberverstehen mit Hörgerät bei 65 dB SPL (EV₆₅(HG)) häufig unter dem maximalen Einsilberverstehen aus dem Sprachaudiogramm (mEV), insbesondere bei Hörgeräteträgern mit hochgradigem Hörverlust. Diese Arbeit zielte darauf ab, den Wirkungsgrad Q der Hörgeräteversorgung, den Quotienten aus EV₆₅(HG) und mEV, bei Hörgeräteträgern mit hochgradigem bis an Taubheit grenzendem Hörverlust zu untersuchen.

Material und Methoden

Es wurden Daten aus In-situ-Messungen, dem Reinton- und Sprachaudiogramm und dem Sprachverstehen mit und ohne Hörgerät von 93 Ohren von 64 Patienten ausgewertet. Die Patienten stellten sich im Jahr 2019 für eine Hörgerätekontrolle in unserem Hörzentrum vor. Es wurden die Abweichung der in-situ gemessenen frequenzabhängigen Ausgangspegelwerte von den Zielvorgaben der präskriptiven Anpassformeln NAL-NL2 und DSL v5.0 analysiert. Für die Parameter EV₆₅(HG) und Q wurden jeweils die Spearman-Korrelationskoeffizienten für den Sprachverständlichkeitsindex (SII) berechnet.

Ergebnisse

Bei mehr als 67 % der Hörgeräteeinstellungen stimmten die Ausgangspegelwerte mit den Zielkurven für NAL-NL2 oder DSL v5.0 im Bereich von ±5 dB für Frequenzen von 0,5 bis 4 kHz für 65 dB SPL überein. Trotzdem wurde das mEV mit Hörgerät bei 65 dB SPL nicht erreicht (mittlere Abweichungen: 34,4 %). EV₆₅(HG) und Q waren jedoch am besten, wenn Zielwerte für DSL v5.0 bei 65 dB SPL erreicht wurden, was mit einem höheren SII einhergeht.

Schlussfolgerung

Für Hörgeräteträger mit hochgradigem bis an Taubheit grenzendem Hörverlust führen die Anpassformeln NAL-NL2 und DSL v5.0 nicht zu einer solchen Verstärkung, dass bei Alltagssprache von 65 dB SPL das mEV erreicht wird. Es bleibt zu untersuchen, ob alternative Präskriptionen mit besserer Hörbarkeit für Eingangspegel von 50 und 65 dB SPL den Wirkungsgrad der Hörgeräteversorgung verbessern könnten.

[Evaluation of hearing aid rehabilitation using the Freiburg Monosyllabic Test]

The benefit of hearing aids is not always directly subjectively perceivable. Therefore, objective and quantifiable speech audiometric measurements are required. Beside acoustic gain measurements and structured interviews, speech audiometry in quiet and in noise is one of the three pillars of hearing aid evaluation.The Freiburg monosyllabic test has been used for decades for hearing aid prescription and evaluation in German speaking countries. Relative and absolute targets can be individually defined for the rehabilitation of speech perception by hearing aids as assessed by the Freiburg monosyllabic test in quiet and at conversational levels.The general applicability of speech audiometric measurements in noise is limited. Alternative ("modern") methods and the definitions of noise situations relevant to everyday life have been discussed for years. However, the introduction of these methods into everyday use has proven difficult. On one hand, there is comparatively little practical experience; on the other, it has not yet been demonstrated what additional benefits these more complicated measurements might have for standard hearing aid evaluations and hearing aid users.

[The age effect in evaluation of hearing aid benefits by speech audiometry]

BACKGROUND AND AIM

Hearing loss is one of the most common disabilities in the elderly. The aim of this study was to investigate the relationship between pure-tone hearing loss and maximum monosyllabic perception and speech perception with hearing aids. The focus of the investigation was elderly patients.

MATERIALS AND METHODS

In this prospective study, 188 patients with sensorineural hearing loss were included. The pure-tone audiogram (4FPTA), the Freiburg speech intelligibility test with headphones and the word recognition score with hearing aids at 65 dB SPL were measured and evaluated.

RESULTS

An increasing age was associated with higher discrepancy between the maximum speech perception and speech understanding with hearing aids. The mean difference between maximum monosyllabic perception and speech perception with hearing aids is about 20% in the elderly population.

CONCLUSION

The intended goal of hearing aid prescription, the match between maximum monosyllabic perception and word recognition score with hearing aids within 5 to 10%, is not achieved in the elderly population.

[Indication for and verification of hearing aid benefit using modern methods of speech audiometry in German]

The current guidelines for hearing aid supply in Germany employ the often criticised Freiburg monosyllabic speech test (FBE) in quiet. This test can be replaced with the monosyllabic rhyme test by von Wallenberg and Kollmeier (WaKo) in quiet and by the measurement of a speech reception threshold in an interfering noise at a moderate level (45 dB SPL) using either the Göttingen or the Oldenburg sentence test (criterion: 2 dB improvement in SNR, "signal-to-noise ratio"). This procedure was investigated in a group of 38 participants with a sensorineural hearing impairment (mild, moderate or severe hearing loss) and 11 volunteers with normal hearing. On average, comparable indications were achieved. Participants with a mild hearing loss and a selective problem with listening in interfering noise were assessed more fairly.

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

BACKGROUND AND OBJECTIVE

In the Swiss version of the Freiburg speech intelligibility test five test words from the original German recording which are rarely used in Switzerland have been exchanged. Furthermore, differences in the transfer functions between headphone and loudspeaker presentation are not taken into account during calibration. New settings for the levels of the individual test words in the recommended recording and small changes in calibration procedures led us to make a verification of the currently used normative values.

PATIENTS AND METHODS

Speech intelligibility was measured in 20 subjects with normal hearing using monosyllabic words and numbers via headphones and loudspeakers.

RESULTS

On average, 50% speech intelligibility was reached at levels which were 7.5 dB lower under free-field conditions than for headphone presentation. The average difference between numbers and monosyllabic words was found to be 9.6 dB, which is considerably lower than the 14 dB of the current normative curves.

CONCLUSIONS

There is a good agreement between our measurements and the normative values for tests using monosyllabic words and headphones, but not for numbers or free-field measurements.

[New aspects of hearing aid fitting in noise-induced hearing loss]

In the past hearing aid fitting frequently turned out to be a problem in patients with noise-induced hearing loss. Selective amplification in the high frequency range and at the same time natural sound and appropriate wearing comfort (open fitting) could not be achieved in numerous cases. Today these problems can be tackled by modern hearing aid technology providing us with efficient feedback suppression algorithms making open fittings possible for many more patients. This development is particularly beneficial for patients with noise-induced hearing loss. Unfortunately, open fitting is in opposition to wearing hearing aids at noisy workplaces. Tight fittings, however, can be used at work if a special listening program for noisy conditions is available. This dilemma is discussed and possible solutions are pointed out.