Precision Audiometry and Ecological Validity: Exploring the Link Between Patient-Reported Outcome Measures and Speech Testing in CI Users

The aim of the study was to measure and compare speech perception in users of electric-acoustic stimulation (EAS) supported by a hearing aid in the unimplanted ear and in bilateral cochlear implant (CI) users under different noise and sound field conditions. Gap listening was assessed by comparing performance in unmodulated and modulated Comité Consultatif International Téléphonique et Télégraphique (CCITT) noise conditions, and binaural interaction was investigated by comparing single source and multisource sound fields. Speech perception in noise was measured using a closed-set sentence test (Oldenburg Sentence Test, OLSA) in a multisource noise field (MSNF) consisting of a four-loudspeaker array with independent noise sources and a single source in frontal position (S0N0). Speech simulating noise (Fastl-noise), CCITT-noise (continuous), and OLSA-noise (pseudo continuous) served as noise sources with different temporal patterns. Speech tests were performed in two groups of subjects who were using either EAS (n = 12) or bilateral CIs (n = 10). All subjects in the EAS group were fitted with a high-power hearing aid in the opposite ear (bimodal EAS). The average group score on monosyllable in quiet was 68.8% (EAS) and 80.5% (bilateral CI). A group of 22 listeners with normal hearing served as controls to compare and evaluate potential gap listening effects in implanted patients. Average speech reception thresholds in the EAS group were significantly lower than those for the bilateral CI group in all test conditions (CCITT 6.1 dB, p = 0.001; Fastl-noise 5.4 dB, p < 0.01; Oldenburg-(OL)-noise 1.6 dB, p < 0.05). Bilateral CI and EAS user groups showed a significant improvement of 4.3 dB (p = 0.004) and 5.4 dB (p = 0.002) between S0N0 and MSNF sound field conditions respectively, which signifies advantages caused by bilateral interaction in both groups. Performance in the control group showed a significant gap listening effect with a difference of 6.5 dB between modulated and unmodulated noise in S0N0, and a difference of 3.0 dB in MSNF. The ability to "glimpse" into short temporal masker gaps was absent in both groups of implanted subjects. Combined EAS in one ear supported by a hearing aid on the contralateral ear provided significantly improved speech perception compared with bilateral cochlear implantation. Although the scores for monosyllable words in quiet were higher in the bilateral CI group, the EAS group performed better in different noise and sound field conditions. Furthermore, the results indicated that binaural interaction between EAS in one ear and residual acoustic hearing in the opposite ear enhances speech perception in complex noise situations. Both bilateral CI and bimodal EAS users did not benefit from short temporal masker gaps, therefore the better performance of the EAS group in modulated noise conditions could be explained by the improved transmission of fundamental frequency cues in the lower-frequency region of acoustic hearing, which might foster the grouping of auditory objects.

Masking release with changing fundamental frequency: Electric acoustic stimulation resembles normal hearing subjects

IntroductionA common concern for individuals with moderate-to-profound hearing loss who have received a cochlear implants (CIs) is difficulty following conversations in noisy environments. A possible reason is the increased use of cognitive resources (attention and working memory) to disambiguate the speech stimuli potentially causing detriments in functional aspects of life. However, this relationship is not well-documented. The overall arching goal of this study was to quantify the relationships between Patient-Reported Outcome Measures (PROMs) and cognitive ability through working memory and speech perception measures.MethodsIn the current study, 31 adult CI users and typical hearing (TH) age-matched controls were recruited. CI users completed PROMs including Speech, Spatial and Quality of hearing survey (SSQ) and versions of a quality of life (QOL) for CI users (CIQOL) and Nijmegen Cochlear Implant Questionnaire (NCIQ). Measures of cognition were assessed using internet-based tools. Outcomes were compared between groups and PROMs and were related to the cognitive tasks.ResultsReduced auditory working memory and speech perception in noise were observed in CI users compared to TH controls. Correlation analyses revealed significant domain-specific PROM relationships with cognitive tasks in CI users, but not in TH controls. The SSQ had more significant relationships compared to the other PROMS.ConclusionThese results suggest that internet-based metrics of cognitive ability are associated with the functional hearing aspects of life in CI users and that SSQ is more sensitive to investigate the cognitive related effects of QOL compared to other commonly used PROMs.

Objectives.Cochlear implant (CI) users typically report impaired ability to understand speech in noise. Speech understanding in CI users decreases with noise due to reduced temporal processing ability, and speech perceptual errors involve stop consonants distinguished by voice onset time (VOT). The current study examined the effects of noise on various speech perception tests while at the same time used cortical auditory evoked potentials (CAEPs) to quantify the change of neural processing of speech sounds caused by noise. We hypothesized that the noise effects on VOT processing can be reflected in N1/P2 measures, the neural changes relate to behavioral speech perception performances.Methods.Ten adult CI users and 15 normal-hearing (NH) people participated in this study. CAEPs were recorded from 64 scalp electrodes in both quiet and noise (signal-to-noise ratio +5 dB) and in passive and active (requiring consonant discrimination) listening. Speech stimulus was synthesized consonant-vowels with VOTs of 0 and 50 ms. N1-P2 amplitudes and latencies were analyzed as a function of listening condition. For the active condition, the P3b also was analyzed. Behavioral measures included a variety of speech perception tasks.Results.For good performing CI users, performance in most speech test was lower in the presence of noise masking. N1 and P2 latencies became prolonged with noise masking. The P3b amplitudes were smaller in CI groups compared to NH. The degree of P2 latency change (0 vs. 50 ms VOT) was correlated with consonant perception in noise.Conclusion.The effects of noise masking on temporal processing can be reflected in cortical responses in CI users. N1/P2 latencies were more sensitive to noise masking than amplitude measures. Additionally, P2 responses appear to have a better relationship to speech perception in CI users compared to N1.

This study presents the results obtained in a group of patients with asymmetric hearing loss undergoing cochlear implantation at our institution. Prognostic factors are discussed in relation to different rehabilitative approaches for asymmetric hearing loss remediation. The current literature is also discussed. Nineteen adult patients with post-verbal asymmetric hearing loss were enrolled. The results were assessed by means of a speech perception test, completed in silence and with background noise, and a speech reception threshold test (Oldenburg Sentence Test). The subjectively perceived benefits were assessed using the Speech, Spatial and Qualities of Hearing Scale. Statistically significant improvements were achieved by all patients in terms of speech perception and speech reception threshold, and in subjective benefits. The results confirm the literature findings which suggest that patients with asymmetric hearing loss generally gain substantial benefit from cochlear implantation because of the binaural input, with significant improvement in speech perception abilities in noise, speech reception threshold, and squelch abilities.

Daily Sound Awareness of CI Users

Music and Cochlear Implants

Background/Objectives: Uptake of remote cochlear implant (CI) services is feasible in clinical studies, but implementation into regular clinical practice is limited. Effective implementation requires demonstration of at least equivalent outcomes to in-person care. Use of outcome measures (e.g., specific tools such as speech tests or surveys) that are relevant and sensitive to both modes of service facilitates evidence-based provision of CI services. Following our previous study, which developed a core outcome domain set (CODS) (i.e., a set of CI outcome areas important to measure), this study aimed to (1) review current awareness and use of outcome measures implemented clinically, in-person, or remotely; and (2) provide recommendations for a pragmatic core outcome set (COS) to assess remote technologies for CI users. Methods: Expert Australian/New Zealand clinical CI professionals (n = 20) completed an online survey regarding use of, and familiarity with, pre-identified outcome measures mapping to the previously identified CODS. Respondents rated the outcomes’ usefulness, ease of use, trustworthiness, and recommendation for future use. Stakeholder workshops (clinician, n = 3, CI users n = 4) finalised recommendations. Results: Four of the six most regularly used and familiar measures were speech perception tests: BKB-A sentences, CNC words, CUNY sentences, and AB words. The long- and short-form Speech, Spatial, and Qualities of Hearing Scales (SSQ/SSQ-12) were the top-ranked patient-reported outcome measures (PROMs). These outcome measures were also perceived as the most trustworthy, easy to use, and likely to be used if recommended. Conclusions: A pragmatic COS, relevant to both remote and in-person delivery of CI services, including recommendations for measurement of service, clinician-measured and patient-reported outcomes, and how these might be developed in future, is recommended.

This paper evaluates the benefit of the two-microphone adaptive beamformer BEAM in the Nucleus Freedom cochlear implant (CI) system for speech understanding in background noise by CI users. A double-blind evaluation of the two-microphone adaptive beamformer BEAM and a hardware directional microphone was carried out with five adult Nucleus CI users. The test procedure consisted of a pre- and post-test in the lab and a 2-wk trial period at home. In the pre- and post-test, the speech reception threshold (SRT) with sentences and the percentage correct phoneme scores for CVC words were measured in quiet and background noise at different signal-to-noise ratios. Performance was assessed for two different noise configurations (with a single noise source and with three noise sources) and two different noise materials (stationary speech-weighted noise and multitalker babble). During the 2-wk trial period at home, the CI users evaluated the noise reduction performance in different listening conditions by means of the SSQ questionnaire. In addition to the perceptual evaluation, the noise reduction performance of the beamformer was measured physically as a function of the direction of the noise source. Significant improvements of both the SRT in noise (average improvement of 5-16 dB) and the percentage correct phoneme scores (average improvement of 10-41%) were observed with BEAM compared to the standard hardware directional microphone. In addition, the SSQ questionnaire and subjective evaluation in controlled and real-life scenarios suggested a possible preference for the beamformer in noisy environments. The evaluation demonstrates that the adaptive noise reduction algorithm BEAM in the Nucleus Freedom CI-system may significantly increase the speech perception by cochlear implantees in noisy listening conditions. This is the first monolateral (adaptive) noise reduction strategy actually implemented in a mainstream commercial CI.

This study investigated the effect of speech rate for Italian-speaking cochlear implant (CI) users with the aim of gaining insight into everyday listening situations where speaker’s rate may vary considerably together with speech level in fluctuating background noise. The test material was prepared by processing the Italian STARR test with temporal compression of sentence material. Twelve adult CI users were divided into two subgroups based on their STARR performance: good and poor performers. The effect of varying speech rate was remarkable for both subgroups. Good performers showed significant performance deterioration for the faster speech rate, whereas outcomes for poor performers improved significantly for the slower speech rate. Background noise is inevitable during daily life and CI users face a variety of speakers, so must cope with changes in both speech level and rate. Traditional tests with a single talker speaking very clearly while using a moderate to low speech rate may overestimate everyday speech perception for CI users. The use of tests that mimic everyday perception is of great importance and should become a routine part of audiometric measures for hearing impaired people.

Although good speech perception in quiet is achievable with cochlear implants (CIs), speech perception in noise is severely impaired compared to normal hearing (NH). In the case of abimodal CI fitting with ahearing aid (HA) in the opposite ear, the amount of residual acoustic hearing influences speech perception in noise. The aim of this work was to investigate speech perception in noise in agroup of bimodal CI users and compare the results to age-matched HA users and people without subjective hearing loss, as well as with ayoung NH group. Study participants comprised 19bimodal CI users, 39HA users, and 40subjectively NH subjects in the age group 60-90years and 14young NH subjects. Speech reception thresholds (SRTs) in noise were adaptively measured using the Oldenburg Sentence Test for the two spatial test conditions S0N0 (speech and noise from the front) and multisource-noise field (MSNF; speech from the front, four spatially distributed noise sources) in continuous noise of the Oldenburg Sentence Test (Ol-noise) and amplitude-modulated Fastl noise (Fastl-noise). With increasing hearing loss, the median SRT worsened significantly in all conditions. In test condition S0N0, the SRT of the CI group was 5.6 dB worse in Ol-noise than in the young NH group (mean age 26.4years) and 22.5 dB worse in Fastl-noise; in MSNF, the differences were 6.6 dB (Ol-noise) and 17.3 dB (Fastl-noise), respectively. In the young NH group, median SRT in condition S0N0 improved by 11 dB due to gap listening; in the older NH group, SRTs improved by only 3.1 dB. In the HA and bimodal CI groups there was no gap listening effect and SRTs in Fastl-noise were even worse than in Ol-noise. With increasing hearing loss, speech perception in modulated noise is even more impaired than in continuous noise.

HintergrundHörgeschädigte Menschen mit asymmetrischem Hörverlust und einseitiger Indikation für ein Cochleaimplantat (CI) profitieren in aller Regel deutlich von einer bimodalen Hörversorgung. Der Einfluss dieser Versorgungsart auf das Sprachverstehen (SV) im zeitlichen Verlauf ist bislang nicht hinreichend untersucht. Die vorliegende Studie untersucht den Einfluss einer bimodalen Versorgung auf das SV postlingual ertaubter, bimodal versorgter CI-Träger:innen nach einer Tragedauer von mindestens 36 Monaten und analysiert dabei mögliche Einflussfaktoren.MethodeEs wurden 54 bimodal versorgte lautsprachkompetente CI-Träger:innen mit einer CI-Erfahrung von mindestens 36 Monaten in diese retrospektive Längsschnittstudie eingeschlossen. Audiometrische Daten von diesen CI-Träger:innen wurden im zeitlichen Verlauf verglichen.ErgebnisseDie Veränderung der Ergebnisse im Freiburger Einsilbertest (FBE) im Verlauf der 36 Monate war für die Ertaubungsgruppe < 10 Jahre sowohl für den Pegel 65 dB „sound pressure level“ (SPL) als auch für 80 dB SPL signifikant und für die Ertaubungsgruppe ≥ 10 Jahre für 65 dB SPL signifikant (p < 5 %). Beim Oldenburger Satztest (OlSa) ergab sich für die Konfigurationen S0, S0N0 und S0NCI eine hochsignifikante Veränderung (p < 0,1 %). und für S0NHG (HG: Hörgerät) eine sehr signifikante Veränderung (p < 1 %). Das Alter bei Versorgung als möglicher Einflussfaktor konnte durch den FBE nicht bestätigt werden. Die Ertaubungsdauer stellte dagegen einen negativen Einflussfaktor für das SV mit dem CI dar, wobei eine längere Ertaubungsdauer mit schlechteren Ergebnissen beim FBE assoziiert ist. Der Grad der Schwerhörigkeit des mit HG versorgten Ohrs beeinflusste das SV nicht. Im Median betrug der bimodale Nutzen (Differenz aus dem SV mit bimodaler Versorgung gegenüber einseitiger HG-Versorgung beim FBE für 65 dB SPL) über die gesamte Untersuchungszeit 10 %. Für im Median 79 % der Versuchspersonen war der bimodale Nutzen über den gesamten Zeitverlauf von 36 Monaten nachweisbar.SchlussfolgerungIm zeitlichen Verlauf verbessert sich das SV mit dem CI der bimodalen Versuchspersonen signifikant. Die untersuchten Einflussfaktoren (Alter, Ertaubungsdauer und Grad der Schwerhörigkeit des Gegenohrs) unterstützen die leitliniengerechte Indikationsstellung einer bimodalen Versorgung in Deutschland – unabhängig von Alter, Ertaubungsdauer und Hörfähigkeit des Gegenohrs – eine Cochleaimplantation durchzuführen.

Although most cochlear implant (CI) users achieve improvements in speech perception, there is still a wide variability in speech perception outcomes. There is a growing body of literature that supports the relationship between individual differences in temporal processing and speech perception performance in CI users. Previous psychophysical studies have emphasized the importance of temporal acuity for overall speech perception performance. Measurement of gap detection thresholds (GDTs) is the most common measure currently used to assess temporal resolution. However, most GDT studies completed with CI participants used direct electrical stimulation not acoustic stimulation and they used psychoacoustic research paradigms that are not easy to administer clinically. Therefore, it is necessary to determine if the variance in GDTs assessed with clinical measures of temporal processing such as the Randomized Gap Detection Test (RGDT) can be used to explain the variability in speech perception performance. The primary goal of this study was to investigate the relationship between temporal processing and speech perception performance in CI users. A correlational study investigating the relationship between behavioral GDTs (assessed with the RGDT or the Expanded Randomized Gap Detection Test) and commonly used speech perception measures (assessed with the Speech Recognition Test [SRT], Central Institute for the Deaf W-22 Word Recognition Test [W-22], Consonant-Nucleus-Consonant Test [CNC], Arizona Biomedical Sentence Recognition Test [AzBio], Bamford-Kowal-Bench Speech-in-Noise Test [BKB-SIN]). Twelve postlingually deafened adult CI users (24-83 yr) and ten normal-hearing (NH; 22-30 yr) adults participated in the study. The data were collected in a sound-attenuated test booth. After measuring pure-tone thresholds, GDTs and speech perception performance were measured. The difference in performance between-participant groups on the aforementioned tests, as well as the correlation between GDTs and speech perception performance was examined. The correlations between participants' biologic factors, performance on the RGDT and speech perception measures were also explored. Although some CI participants performed as well as the NH listeners, the majority of the CI participants displayed temporal processing impairments (GDTs > 20 msec) and poorer speech perception performance than NH participants. A statistically significant difference was found between the NH and CI test groups in GDTs and some speech tests (SRT, W-22, and BKB-SIN). For the CI group, there were significant correlations between GDTs and some measures of speech perception (CNC Phoneme, AzBio, BKB-SIN); however, no significant correlations were found between biographic factors and GDTs or speech perception performance. Results support the theory that the variability in temporal acuity in CI users contributes to the variability in speech performance. Results also indicate that it is reasonable to use the clinically available RGDT to identify CI users with temporal processing impairments for further appropriate rehabilitation.

Evaluation of noise reduction technologies in a contemporary cochlear implant system

Temporal fluctuations of water flux have been investigated as a mechanism that strongly enhances transverse dispersion in heterogeneous media. Unfortunately, most results have been obtained by linear stochastic theories on permeability fields of limited variability. Worse, results are inconsistent regarding the impact of fluctuations on longitudinal dispersion, which motivates our work to find the effect of temporal velocity fluctuations on macrodispersion. We perform numerical Monte Carlo simulations for highly variable permeability fields of up to 800 correlation lengths. We find that fluctuations longitudinal to the main flow direction hardly modify macrodispersion because they do not alter the flow lines. Fluctuations transverse to the main flow direction not only increase transverse dispersion, which is well known, but also reduce the longitudinal macrodispersion in a significant and consistent way, which contradicts previous findings. The reduction of the longitudinal dispersion is comparable to the increase of transverse dispersion. Most surprisingly, for high heterogeneity, temporal fluctuations cause total (longitudinal plus transverse) macrodispersion to drop with respect to the steady state one. Enhancement of the transverse macrodispersion comes from both the increase of the transverse velocity variability and Lagrangian correlation. Reduction of the longitudinal macrodispersion results from the reduction of the Lagrangian correlation of the longitudinal velocity. That is, temporal fluctuations reduce longitudinal spreading both by breaking the fastest velocity paths on the plume front and by letting solute bypass the low‐permeability zones that tend to block or trap the solute in steady state flow conditions.