Benefits from upgrade to the CP810™ sound processor for Nucleus® 24 cochlear implant recipients

Predicting Matrix Test Effectiveness for Evaluating Auditory Performance in Noise Using Pure-Tone Audiometry and Speech Recognition in Quiet in Cochlear Implant Recipients

INTRODUCTION

Auditory performance in noise of cochlear implant recipients can be assessed with the adaptive Matrix test (MT); however, when the speech-to-noise ratio (SNR) exceeds 15 dB, the background noise has any negative impact on the speech recognition. Here, we aim to evaluate the predictive power of aided pure-tone audiometry and speech recognition in quiet and establish cut-off values for both tests that indicate whether auditory performance in noise can be assessed using the Matrix sentence test in a diffuse noise environment.

METHODS

Here, we assessed the power of pure-tone audiometry and speech recognition in quiet to predict the response to the MT. Ninety-eight cochlear implant recipients were assessed using different sound processors from Advanced Bionics (n = 56) and CochlearTM (n = 42). Auditory tests were performed at least 1 year after cochlear implantation or upgrading the sound processor to ensure the best benefit of the implant. Auditory assessment of the implanted ear in free-field conditions included: pure-tone average (PTA), speech discrimination score (SDS) in quiet at 65 dB, and speech recognition threshold (SRT) in noise that is the SNR at which the patient can correctly recognize 50% of the words using the MT in a diffuse sound field.

RESULTS

The SRT in noise was determined in 60 patients (61%) and undetermined in 38 (39%) using the MT. When cut-off values for PTA <36 dB and SDS >41% were used separately, they were able to predict a positive response to the MT in 83% of recipients; using both cut-off values together, the predictive value reached 92%.

DISCUSSION

As the pure-tone audiometry is standardized universally and the speech recognition in quiet could vary depending on the language used; we propose that the MT should be performed in recipients with PTA <36 dB, and in recipients with PTA >36 dB, a list of Matrix sentences at a fixed SNR should be presented to determine the percentage of words understood. This approach should enable clinicians to obtain information about auditory performance in noise whenever possible.

Value of patient-reported outcome measures for evaluating the benefit of speech processor upgrading in patients with cochlear implants

BACKGROUND

Patients with a cochlear implant (CI) should be evaluated for a new speech processor every 6 years. The aim of this analysis was to assess the subjective and audiological benefit of upgrades.

METHODS

Speech understanding and subjective benefit were analyzed in 99 patients with the old and the new speech processor after 4 weeks of wearing. Speech understanding was assessed using the Freiburg monosyllabic test in quiet (FBE) at 65 dB and 80 dB, and the Oldenburg Sentence Test (OLSA) at 65 dB noise with adaptive speech sound level. The Abbreviated Profile of Hearing Aid Benefit (APHAB) was used to assess subjective hearing impairment, and the Audio Processor Satisfaction Questionnaire (APSQ) was used to assess subjective satisfaction.

RESULTS

The speech processor upgrade resulted in a significant improvement of speech understanding in quiet at 65 dB (mean difference 8.9 ± 25.9 percentage points, p < 0.001) and 80 dB (mean difference 8.1 ± 29.7 percentage points, p < 0.001) and in noise (mean difference 3.2 ± 10.7 dB signal-to-noise ratio [S/N], p = 0.006). Using the APHAB, a significant improvement (mean difference 0.07 ± 0.16, p < 0.001) in hearing impairment was demonstrated in all listening situations. The APSQ showed significantly higher patient satisfaction with the new speech processor (mean difference 0.42 ± 1.26, p = 0.006). A comparative assessment of the benefit based on subjective and speech audiometric results identified a proportion of patients (35-42%) who subjectively benefited from the upgrade but had no measurable benefit based on speech audiometry.

CONCLUSION

There was a significant improvement in audiologically measurable and subjectively reflected speech understanding and patient satisfaction after the upgrade. In patients with only a small improvement in audiologically measurable speech understanding, the subjective benefit should also be assessed with validated measurement instruments in order to justify an upgrade to the payers in the health sector.

[Value of patient-reported outcome measures for evaluating the benefit of speech processor upgrading in patients with cochlear implants. German version]

BACKGROUND

Patients with a cochlear implant (CI) should be evaluated for a new speech processor every 6 years. The aim of this analysis was to assess the subjective and audiological benefit of upgrades.

METHODS

Speech understanding and subjective benefit were analyzed in 99 patients with the old and the new speech processor after 4 weeks of wearing. Speech understanding was assessed using the Freiburg monosyllabic test in quiet (FBE) at 65 dB and 80 dB, and the Oldenburg Sentence Test (OLSA) at 65 dB noise with adaptive speech sound level. The Abbreviated Profile of Hearing Aid Benefit (APHAB) was used to assess subjective hearing impairment, and the Audio Processor Satisfaction Questionnaire (APSQ) was used to assess subjective satisfaction.

RESULTS

The speech processor upgrade resulted in a significant improvement of speech understanding in quiet at 65 dB (mean difference 8.9 ± 25.9 percentage points, p < 0.001) and 80 dB (mean difference 8.1 ± 29.7 percentage points, p < 0.001) and in noise (mean difference 3.2 ± 10.7 dB signal-to-noise ratio [S/N], p = 0.006). Using the APHAB, a significant improvement (mean difference 0.07 ± 0.16, p < 0.001) in hearing impairment was demonstrated in all listening situations. The APSQ showed significantly higher patient satisfaction with the new speech processor (mean difference 0.42 ± 1.26, p = 0.006). A comparative assessment of the benefit based on subjective and speech audiometric results identified a proportion of patients (35-42%) who subjectively benefited from the upgrade but had no measurable benefit based on speech audiometry.

CONCLUSION

There was a significant improvement in audiologically measurable and subjectively reflected speech understanding and patient satisfaction after the upgrade. In patients with only a small improvement in audiologically measurable speech understanding, the subjective benefit should also be assessed with validated measurement instruments in order to justify an upgrade to the payers in the health sector.

Prospective Comparison Between Manual and Computer-Assisted (FOX) Cochlear Implant Fitting in Newly Implanted Patients

OBJECTIVE

A prospective, longitudinal, randomized controlled trial with an original crossover design for 1 year was conducted to compare manual fitting to artificial intelligence-based fitting in newly implanted patients.

DESIGN

Twenty-four patients who received their first cochlear implant (CI) were randomly assigned to the manual or Fitting to Outcome eXpert (FOX) arm; they followed the corresponding fitting procedures for 1 year. After 1 year, each patient was switched to another arm. The number of fittings, auditory outcomes (pure-tone thresholds, loudness scaling curves, spectral discrimination scores, bisyllabic word recognition in quiet and noise, and speech tracking), fitting session questionnaire, and CI parameters (T level, C level, Threshold Sound Pressure Level (T-SPL), Comfortable Sound Pressure Level (C-SPL), and loudness growth value) were compared between the two groups. Differences between the two groups were analyzed using the Mann-Whitney test, and Holm corrections were applied for multiple statistical tests. At the end of the crossover session, patients were offered the choice to continue with their old or new map.

RESULTS

As early as 3 mo postactivation, the FOX group showed less variability and significantly better speech intelligibility in quiet conditions at 40 and 55 dB SPL and noise ( p < 0.05) with median phoneme scores of 50%, 70%, and 50% at 55, 70, and 85 dB SPL compared with 45%, 50%, and 40%, respectively. This group showed better results at 12 mo postactivation ( p < 0.05). In the manual group, 100% of the patients decided to keep the new FOX map, and 82% performed better with the FOX map. In the FOX group, 63% of the patients decided to keep the manual map, although the measurable outcome had not improved. In this group, participants reported to prefer the manual map because it felt more comfortable, even if the FOX map gave better measured outcome.

CONCLUSION

Although the study size remains relatively small, the AI-FOX approach was equivalent to or even outperformed the manual approach in hearing performance, comfort, and resources. Furthermore, FOX is a tool capable of continuous improvement by comparing its predictions with observed results and is continuously learning from clinicians' practice, which is why this technology promises major advances in the future.

The COVID-19 pandemic and upgrades of CI speech processors for children: part II-hearing outcomes

PURPOSE

To gauge the benefits to children of upgrading speech processors during the COVID-19 pandemic.

METHODS

The study involved 297 children, aged from 7.3 to 18.0 years, whose processors were upgraded to either Nucleus 7 or Kanso 2, or to Sonnet 2 or Rondo 3. To document the benefits of the upgrades, a speech-in-noise discrimination test and Patient Reported Outcome Measures (PROMs) were used.

RESULTS

There was a significant benefit from the newer processors in terms of speech discrimination in noise. Patient Reported Outcome Measures (PROMs) indicated less hearing disability, a higher level of functioning in everyday life situations, and more satisfaction with the new speech processor in social situations.

CONCLUSION

There is a measurable improvement in performance when the devices are upgraded to the new technology.

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.

The effects of behind-the-ear and off-the-ear sound processors on speech understanding performance in cochlear implant users

OBJECTIVE

The first aim of this study was to compare speech understanding performance in adult cochlear implant users using behind-the-ear and off-the-ear sound processors in quiet and noise. Second, the impact of sound processor microphone location on speech understanding performance was compared.

METHODS

Participants were tested with both types of sound processors in the free field with warble tones, and speech discrimination scores in quiet were obtained. Turkish Matrix Test was used to measure speech understanding in noise with five different loudspeaker settings. Twenty-seven participants of cochlear implants between 16 and 67 years-of-age using behind-the-ear or off-the-ear sound processors were included in the study. The results obtained with two types of sound processors were compared.

RESULTS

Aided free field thresholds were significantly better for the behind-the-ear vs. off-the-ear sound processor. The mean difference was 3.3 dB HL. There was no significant difference in speech discrimination scores in quite between the two processors (p > 0.05). Statistically significant differences were not seen for speech intelligibility in five spatial settings in the Turkish Matrix Test (p > 0.05).

CONCLUSION

Although both types of sound processors had different microphone locations, the outcomes were found to be consistent with previous results in adult users off-the-ear sound processors, demonstrating equivalent speech understanding in quiet and noise.

Benefits in noise from sound processor upgrade in thirty-three cochlear implant users for more than 20 years

PURPOSE

Some oldest patients rehabilitated with a cochlear implant more than 20 years ago could still be upgraded with new generations of speech processor (SP). The aim of this study was to show the benefit of a recent generation of SP in this population.

METHODS

A monocentric prospective study was designed to evaluate the performance of 33 ancient CI22M users implanted between 1989 and 1997 and upgraded with the late compatible sound processor CP900. Performance was evaluated in quiet and noise with Framatix, an automated adaptative test.

RESULTS

Performance using Framatix significantly improved with the CP900, with a decrease of the median speech perception threshold of 6 dB in quiet (p < 0.05) and 5,3 dB in noise (p < 0.0005). No subjective benefit using the APHAB questionnaire was observed.

CONCLUSION

Upgrading of cochlear implant recipients who were implanted more than 20 years ago with recent compatible and new technological SP provide benefit in speech recognition in noise.

Speech understanding and listening effort in cochlear implant users - microphone beamformers lead to significant improvements in noisy environments

Objectives: To evaluate the effect of microphone directionality, i.e. beamforming, on speech understanding in noise with the SONNET audio processor.Methods: Speech reception thresholds (SRTs) were tested in three different microphone settings (omnidirectional, adaptive, and fixed beamformer (natural)) and assessed via the Oldenburg Sentence Test and the Just Understanding Speech Test. Subjects rated the listening effort needed to understand speech in different signal-to-noise ratios (-10, -5, 0, 5, 10, 15 dB SNR) via a Visual Analogue Scale. For all test methods, speech was presented at 0° azimuth while fixed and uncorrelated masking noise was presented simultaneously from five loudspeakers positioned at ±70°, ±135°, and 180° azimuth.Results: Compared to the omnidirectional mode, significant improvements (p<0.001) were shown in mean SRTs for both the natural (3.3 dB SNR) and adaptive (5.2 dB SNR) settings. Using the natural or the adaptive setting required significantly less listening effort than using the omnidirectional setting for the SNR conditions -5 dB SNR (p=0.002) and 0 dB SNR (p<0.001).Discussion: The beamformer settings significantly improved speech understanding in noise over the omnidirectional setting. Due our multi-speaker test setup, we conclude that beamforming should yield significantly better and less stressful speech understanding in demanding real-life listening situations.

The Oticon Medical Neuro Zti cochlear implant and the Neuro 2 sound processor: multicentric evaluation of outcomes in adults and children

Objective: This study evaluated the outcomes of the Oticon Medical Neuro Zti cochlear implant and the Neuro 2 sound processor.Design: Neuro One users were upgraded to Neuro 2. Monosyllabic word identification was evaluated in adults with Neuro One after ≥5 months, with Neuro 2 at upgrade, and with Neuro 2 after 3 months. Self-reported listening ability, satisfaction, and usability were measured in adults and children.Study sample: Participants were 44 adults and 26 children.Results: Speech identification scores in quiet and noise were 58% and 45% with Neuro One and 67% and 55% with Neuro 2 after 3 months, respectively. Hearing impairment duration and number of active electrodes significantly predicted speech identification in noise with Neuro 2. Significantly higher questionnaire ratings were obtained for Neuro 2 than Neuro One regarding listening ability in complex listening situations, comfort and music, as well as nine aspects of satisfaction and usability.Conclusion: This study demonstrates the clinical superiority of the Neuro 2 sound processor over Neuro One in terms of speech identification in quiet and in noise and reported patient benefit and satisfaction. Given the study design, sources of improvement may include factors unrelated to the sound processor itself.

[Speech processor upgrade increases speech comprehension in patients with cochlear implants]

BACKGROUND

Hearing rehabilitation of patients with severe hearing loss by cochlear implant (CI) enhances their opportunities for communication immensely with regard to their normal-hearing social environment. The degree of participation depends decisively on speech discrimination. This study examines whether speech discrimination can be improved by equipping patients with next-generation speech processors (SP).

METHODS

The changes in speech discrimination of 420 CI patients upon receiving a newer SP from 2003-2012 were retrospectively analyzed. Audiometry comprised the Freiburg number and monosyllable tests and the Oldenburg sentence test in quiet and noise, with a presentation volume of 70 dB.

RESULTS

In all audiometric tests, the newer SP showed a significant improvement compared to the preceding SP. This improvement was attainable for the majority of patients and was independent of age.

CONCLUSION

Upgrade of the SP results in improved speech discrimination. This holds true for several test settings. We therefore recommend earlier upgrades and that the costs for new SP be met.

Controlled comparative clinical trial of hearing benefit outcomes for users of the Cochlear™ Nucleus® 7 Sound Processor with mobile connectivity

OBJECTIVES

To assess subjective benefits and objective speech recognition performance following a take-home trial with the new Cochlear™ Nucleus^® 7 Sound Processor (SP), in experienced users of compatible cochlear implants from Cochlear Limited.

METHODS

A total of 37 adult participants were fitted with the Nucleus 7 SP and used the device for up to one year. Baseline speech recognition was assessed at the initial fitting session, using each participant's own SP, and Client Oriented Scale of Improvement (COSI) goals were identified. Speech recognition was measured after 3 months of device use and outcomes of the COSI and a non-validated Processor Comparison Questionnaire (PCQ) were collected. After 11 months, a subset of subjects were tested on speech recognition delivered via direct wireless streaming from an Apple^® smartphone to the SP and compatible hearing aid on the opposite side (if worn).

RESULTS

The COSI and PCQ instruments both indicated significant improvement in perceived subjective benefits in comparison to the participants' previous SPs. Direct streaming via an Apple mobile phone showed improvements when compared with the acoustic alone condition. Standard speech recognition in quiet and noise was equivalent to that obtained using a previous generation SP which uses the same basic processing as the Nucleus 7 Sound Processor.

CONCLUSIONS

The incremental refinements provided by the Nucleus 7 Sound Processor provide real-world benefits in key areas such as upgraded wireless connectivity. The COSI proved to be an effective tool for individualized assessment of specific benefits that may not be addressed by more standardized instruments.

Fixed and adaptive beamforming improves speech perception in noise in cochlear implant recipients equipped with the MED-EL SONNET audio processor

Objective

To determine the impact of the fixed and adaptive beamforming technology of the new MED-EL SONNET cochlear implant audio processor on speech perception in noise.

Methods

The study cohort comprises 18 postlingually deafened adult cochlear implant recipients with at least six months of experience. Speech reception thresholds were measured with the Oldenburg Sentence Test in continuous, speech-shaped noise. Target sentences were presented in front of the listener, with noise sources placed at -135° and 135°, respectively. Outcome measures were the differences in speech reception threshold using omnidirectional, fixed and adaptive beamformer microphone settings.

Results

The use of directional microphones significantly improved speech reception thresholds: fixed beamformer vs. omnidirectional: 4.3 dB (95%-CI [3.1; 5.5]), p<0.0001; adaptive beamformer vs. omnidirectional: 6.1 dB (95%-CI [4.9; 7.3]), p<0.0001; and adaptive beamformer vs. fixed beamformer: 1.8 dB (95%-CI [0.7; 3.0]), p = 0.001.

Conclusion

This study confirms the previously reported improvements in speech perception in noise of the fixed beamformer microphone setting and is the first to report significant improvements in speech perception in noise when applying the adaptive beamformer microphone settings of the SONNET audio processor. Cochlear implant users may be able to benefit from improved hearing performance especially in difficult listening situations.

A clinical assessment of cochlear implant recipient performance: implications for individualized map settings in specific environments

Individual speech intelligibility was measured in quiet and noise for cochlear Implant recipients upgrading from the Freedom to the CP900 series sound processor. The postlingually deafened participants (n = 23) used either Nucleus CI24RE or CI512 cochlear implant, and currently wore a Freedom sound processor. A significant group mean improvement in speech intelligibility was found in quiet (Freiburg monosyllabic words at 50 dB_SPL) and in noise (adaptive Oldenburger sentences in noise) for the two CP900 series SmartSound programs compared to the Freedom program. Further analysis was carried out on individual’s speech intelligibility outcomes in quiet and in noise. Results showed a significant improvement or decrement for some recipients when upgrading to the new programs. To further increase speech intelligibility outcomes when upgrading, an enhanced upgrade procedure is proposed that includes additional testing with different signal-processing schemes. Implications of this research are that future automated scene analysis and switching technologies could provide additional performance improvements by introducing individualized scene-dependent settings.

Speech Intelligibility in Various Noise Conditions with the Nucleus® 5 CP810 Sound Processor

The Nucleus^® 5 System Sound Processor (CP810, Cochlear™, Macquarie University, NSW, Australia) contains two omnidirectional microphones. They can be configured as a fixed directional microphone combination (called Zoom) or as an adaptive beamformer (called Beam), which adjusts the directivity continuously to maximally reduce the interfering noise. Initial evaluation studies with the CP810 had compared performance and usability of the new processor in comparison with the Freedom™ Sound Processor (Cochlear™) for speech in quiet and noise for a subset of the processing options. This study compares the two processing options suggested to be used in noisy environments, Zoom and Beam, for various sound field conditions using a standardized speech in noise matrix test (Oldenburg sentences test). Nine German-speaking subjects who previously had been using the Freedom speech processor and subsequently were upgraded to the CP810 device participated in this series of additional evaluation tests. The speech reception threshold (SRT for 50% speech intelligibility in noise) was determined using sentences presented via loudspeaker at 65 dB SPL in front of the listener and noise presented either via the same loudspeaker (S₀N₀) or at 90 degrees at either the ear with the sound processor (S₀N_CI+) or the opposite unaided ear (S₀N_CI-). The fourth noise condition consisted of three uncorrelated noise sources placed at 90, 180 and 270 degrees. The noise level was adjusted through an adaptive procedure to yield a signal to noise ratio where 50% of the words in the sentences were correctly understood.

In spatially separated speech and noise conditions both Zoom and Beam could improve the SRT significantly. For single noise sources, either ipsilateral or contralateral to the cochlear implant sound processor, average improvements with Beam of 12.9 and 7.9 dB in SRT were found. The average SRT of –8 dB for Beam in the diffuse noise condition (uncorrelated noise from both sides and back) is truly remarkable and comparable to the performance of normal hearing listeners in the same test environment. The static directivity (Zoom) option in the diffuse noise condition still provides a significant benefit of 5.9 dB in comparison with the standard omnidirectional microphone setting. These results indicate that CI recipients may improve their speech recognition in noisy environments significantly using these directional microphone-processing options.

Changes in children's speech discrimination and spatial release from masking between 2 and 4 years after sequential cochlear implantation

OBJECTIVE

To document changes in speech reception thresholds (SRTs) and spatial release from masking (SRM) for sequentially implanted children at 2 and 4 years after they received their second cochlear implant (CI2).

METHODS

Participants were 17 children who consistently used two sequentially implanted and optimally programmed CIs. SRTs were measured monaurally in quiet and binaurally in noise using the adaptive McCormick toy discrimination test. Speech signals were presented from 0° azimuth and noise from 0°, +90° or  -90° azimuth. SRM was calculated from SRTs in noise. Measurements were made at 2 and 4 year post-CI2.

RESULTS

There were significant improvements over time in SRTs in quiet, SRTs in noise and SRM. SRTs in quiet improved more for CI2 than for the first implant (CI1). SRTs in noise and SRM improved more when noise was presented closest to CI1 than when closest to CI2. Performance became more symmetrical over time.

DISCUSSION

Despite prolonged periods of unilateral auditory deprivation sequentially implanted children exhibited continued improvement in SRT and SRM. These results are valuable in setting expectations for and counselling families of children considering sequential CIs.