Multizentrische Analyse des Nutzerverhaltens von Cochlea-Implantat-Trägern

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.

Ecological Momentary Assessment to Obtain Signal Processing Technology Preference in Cochlear Implant Users

Background: To assess the performance of cochlear implant users, speech comprehension benefits are generally measured in controlled sound room environments of the laboratory. For field-based assessment of preference, questionnaires are generally used. Since questionnaires are typically administered at the end of an experimental period, they can be inaccurate due to retrospective recall. An alternative known as ecological momentary assessment (EMA) has begun to be used for clinical research. The objective of this study was to determine the feasibility of using EMA to obtain in-the-moment responses from cochlear implant users describing their technology preference in specific acoustic listening situations. Methods: Over a two-week period, eleven adult cochlear implant users compared two listening programs containing different sound processing technologies during everyday take-home use. Their task was to compare and vote for their preferred program. Results: A total of 205 votes were collected from acoustic environments that were classified into six listening scenes. The analysis yielded different patterns of voting among the subjects. Two subjects had a consistent preference for one sound processing technology across all acoustic scenes, three subjects changed their preference based on the acoustic scene, and six subjects had no conclusive preference for either technology. Conclusion: Results show that EMA is suitable for quantifying real-world self-reported preference, showing inter-subject variability in different listening environments. However, there is uncertainty that patients will not provide sufficient spontaneous feedback. One improvement for future research is a participant forced prompt to improve response rates.

Speech comprehension across multiple CI processor generations: Scene dependent signal processing

OBJECTIVES

In clinical practice, characterization of speech comprehension for cochlear implant (CI) patients is typically administered by a set of suprathreshold measurements in quiet and in noise. This study investigates speech comprehension of the three most recent cochlear implant sound processors; CP810, CP910, and CP1000 (Cochlear Limited). To compare sound processor performance across generations and input dynamic range changes, the state-of-the art signal processing technologies available in each sound processor were enabled. Outcomes will be assessed across a range of stimulation intensities, and finally analyzed with respect to normal hearing listeners.

METHODS

In a prospective study, 20 experienced postlingually deafened CI patients who received a Nucleus CI in the ENT department of the University Hospital of SH in Kiel were recruited. Speech comprehension was measured in quiet at 40, 50, and 65 dBSPL with monosyllabic words as well as by speech reception threshold for two-digit numbers. In noise, speech reception thresholds were measured with the adaptive German matrix test with speech and noise in front.

RESULTS

We found that high levels of open-set speech comprehension are achieved at suprathreshold presentation levels in quiet. However, results at lower test levels have remained mostly unchanged for tested sound processors with default dynamic range. Expanding the lower limit of the acoustic input dynamic range yields better speech comprehension at lower presentation levels. In noise the application of ForwardFocus improves the speech reception. Overall, a continuous improvement for speech perception across three generations of CI sound processors was found.

CONCLUSIONS

Findings motivate further development of signal pre-processing, an additional focus of clinical work on lower stimulation levels, and automation of ForwardFocus.

LEVEL OF EVIDENCE

2.

[Impact of CI use and CI fitting on speech production in very early cochlear-implanted infants]

BACKGROUND

Children's age at implantation is an important factor for their outcome in auditory and language skills with a cochlear implant (CI). CI use and frequency of CI fitting may also influence speech performance. Purpose of this study was to evaluate CI use and CI fitting of very early implanted infants and its potential influence on age-related speech production performance.

METHODS

Data of 34 bilaterally cochlea-implanted infants (age at CI in months: M = 8,8; SD = 1,7) were included. During the third year of life speech production performance was evaluated and related to datalogging-based CI use and number of CI fitting sessions.

RESULTS

About half of the cohort achieved speech production level within the normal range of hearing peers. Daily time of CI use was approximately 8 h. Analysis of listening environment showed that infants were exposed most of the time to quiet environment and least amount of time to speech in noise. Daily time of CI use seems to be a significant predictor of speech production, speech-exposition particularly predicts word production. Number of daily disconnection between CI-processor and implant as well as the monthly number of CI fitting sessions were not correlated with speech production.

CONCLUSION

Very early cochlear implanted infants may achieve age-appropriate speech production performance in the third year of life. Time of daily CI use in the study cohort is comparable to results of other studies. Time of daily CI use and exposure to speech seem to be important factors for early speech production. These findings should be integrated in pre- and postoperative parent counselling.

Evaluation of a synthetic version of the digits-in-noise test and its characteristics in CI recipients

OBJECTIVE

The goal of this study was the evaluation of a synthetic version of the Digits-in-Noise (DiN) in participants with normal hearing. Additionally, the basis characteristics of the DiN in CI recipients were investigated.

DESIGN AND STUDY SAMPLE

Twenty participants with normal hearing and 21 CI recipients with a Nucleus®-System ran two to three adaptive and up to five fixed measurements. Afterwards the discrimination function was measured with fixed signal-to-noise ratios.

RESULTS

All subjects were able to perform the DiN within three minutes per test run. The median speech reception threshold (SRT) for the NH was -8.1 dB_SNR, with a median steepness of 23%/dB_SNR. The median absolute test-retest difference in the NH group was 0.4 dB (range: 0 to 1.5 dB). In the CI group, the SRTs range from -6.6 to +12.4 dB_SNR with a median test-retest difference of 0.4 dB (range: 0 to 6.1 dB).

CONCLUSION

The synthetic DiN is a valuable complement of the audiometric test battery in CI recipients. The excellent applicability is also particularly helpful in poor performing CI recipients. With its small time exposure, it is a time- and cost-saving test, which could also be used at home via app to check the individual hearing success.

ForwardFocus with cochlear implant recipients in spatially separated and fluctuating competing signals - introduction of a reference metric

Objective: To clinically evaluate ForwardFocus in noise with experienced Nucleus^® cochlear implant (CI) recipients.Design: Listening performance with ForwardFocus was compared against the best in class directional microphone program (BEAM^®). Speech comprehension was tested with the Oldenburg sentence test with competing signals (stationary, three, six and 18-talker babble) in both co-located and spatially-separated listening environments. Additionally, normal hearing participants were tested monaurally in the same listening environments as a reference and to promote cross-study comparisons between CI clinical study outcomes.Study sample: Post-lingually deaf adult CI recipients (n = 20) who were experienced users of the Nucleus sound processor (Cochlear Limited).Results: Improved speech comprehension was found with the ForwardFocus program compared to the BEAM program in a co-located frontal listening environment for both stationary and fluctuating competing signals. In spatially-separated environments ForwardFocus provided significant speech reception threshold (SRT) improvements of 5.8 dB for three-talker competing signals, respectively.Conclusions: ForwardFocus was shown to significantly improve speech comprehension in a wide range of listening environments. This technology is likely to provide significant improvements in real-world listening for CI recipients, given the clinically relevant performance outcomes in challenging dynamic noise environments, bringing their performance closer to their normal hearing peers.