Daily Sound Awareness of CI Users

1) Environmental sound awareness (ESA) and speech recognition skills in experienced, adult cochlear implant (CI) users will be highly correlated, and, 2) ESA skills of CI users will be significantly lower than those of age-matched adults with normal hearing. Enhancement of ESA is often discussed with patients with sensorineural hearing loss as a potential benefit of implantation and, in some cases, ESA may be a major motivating factor. Despite its ecological validity and patients' expectations, ESA remains largely a presumed skill. The relationship between ESA and speech recognition is not well-understood. ESA was assessed in 35 postlingually deaf, experienced CI users and a control group of 41 age-matched, normal hearing listeners using the validated, computerized familiar environmental sounds test-identification (FEST-I) and a diverse speech recognition battery. Demographic and audiological factors as well as nonverbal intelligence quotient (IQ)/nonverbal reasoning and spectral resolution were assessed. Six of the 35 experienced CI users (17%) demonstrated FEST-I accuracy within the range of the NH controls. Among CI users all correlations between FEST-I accuracy and speech recognition scores were strong. Chronological age at the time of testing, duration of deafness, spectral resolution, and nonverbal IQ/nonverbal reasoning were strongly correlated with FEST-I accuracy. Partial correlation analysis showed that correlations between FEST-I and speech recognition measures remained significant when controlling for the demographic and audiological factors. Our findings reinforce the hypothesis that ESA and speech perception share common underlying processes rather than reflecting truly separate auditory domains.

Objectives: Improved perception of environmental sounds (PES) is one of the primary benefits of cochlear implantation (CI). However, past research contains mixed findings on PES ability in contemporary CI users, which at times contrast with anecdotal clinical reports. The present review examined extant PES research to provide an evidence basis for clinical counseling, identify knowledge gaps, and suggest directions for future work in this area of CI outcome assessment.Methods: Six electronic databases were searched using medical subject headings (MeSH) and keywords broadly identified to reference CI and environmental sounds. Records published between 2000 and 2021 were screened by two independent reviewers in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) statement to identify studies that met the inclusion criteria. Data were subsequently extracted and evaluated according to synthesis without-meta-analysis (SWiM) guidelines.Results: Nineteen studies met the inclusion criteria. Most examined PES in post-lingually implanted adults, with one study focused on pre/perilingual adults. Environmental sound identification (ESI) in quiet using open- or closed-set response format was most commonly used in PES assessment, included in all selected studies. ESI accuracy in CI children (3 studies) and adults (16 studies), was highly variable but generally mediocre (means range: 31–87%). Only two studies evaluated ESI performance prospectively before and after CI, while most studies were cross-sectional. Overall, CI performance was consistently lower than that of normal-hearing peers. No significant differences in identification accuracy were reported between CI candidates and CI users. Environmental sound identification correlated in CI users with measures of speech perception, music and spectro-temporal processing.Conclusion: The findings of this systematic review indicate considerable limitations in the current knowledge of PES in contemporary CI users, especially in pre/perilingual late-implanted adults and children. Although no overall improvement in PES following implantation was found, large individual variability and existing methodological limitations in PES assessment may potentially obscure potential CI benefits for PES. Further research in this ecologically relevant area of assessment is needed to establish a stronger evidence basis, identify CI users with significant deficits, and improve CI users' safety and satisfaction through targeted PES rehabilitation.

Music-based rehabilitation in cochlear implant users: Insights from brain-plasticity research

Active listening in everyday settings is challenging and requires substantial mental effort, particularly in noisy settings. In some cases, effortful listening can lead to significant listening-related fatigue and negatively affect quality of life. However, our understanding of factors that affect the severity of fatigue is limited. Hearing aids and cochlear implants (CIs) can improve speech understanding and thus, potentially, reduce listening effort and fatigue. Some research supports this idea for adult hearing aid users with mild-to-moderate hearing loss, but similar work in CI users is very limited. This study examined (1) longitudinal changes in listening-related fatigue in new and established CI users, and (2) relationships between demographic and audiologic factors and preimplantation and postimplantation listening-related fatigue. Participants included an experimental group of 48 adult CI candidates receiving either a unilateral implant (n = 46) or simultaneous, bilateral implants (n = 2) and a control group of 96 experienced (>12 months experience) adult CI users (50 unilateral, 46 bilateral). Listening-related fatigue was evaluated using the 40-item version of the Vanderbilt Fatigue Scale for Adults. Experimental group ratings were obtained before implantation and again at 0.5-, 1-, 2-, 3-, 6-, and 12-month(s) postactivation. Control group participants completed the scale twice-upon study entry and approximately 3 months later. Additional measures, including a social isolation and disconnectedness questionnaire, hearing handicap inventory, and the Effort Assessment Scale, were also administered at multiple time points. The role of these measures and select demographic and audiologic factors on preimplant and postimplant fatigue ratings were examined. Adult CI candidates reported significantly more fatigue, greater self-perceived hearing handicap, greater listening effort, and more social isolation than experienced adult CI users. However, significant reductions in fatigue and effort were observed within 2 weeks postimplantation. By 3 months, there were no significant differences in fatigue, effort, hearing handicap, or social isolation between new CI recipients and experienced CI users. Secondary analyses revealed that age at onset of hearing loss (before or after 2 years of age) and subjective hearing handicap contributed significantly to the variance of preimplantation fatigue ratings (those with higher handicap reported higher fatigue). In contrast, variance in postimplantation fatigue ratings was not affected by age of hearing loss onset but was affected by gender (females reported more fatigue than males) and subjective ratings of effort, handicap, and isolation (those reporting more effort, handicap, and isolation reported more fatigue). Listening-related fatigue is a significant problem for many CI candidates, as well as for many experienced unilateral and bilateral CI users. Receipt of a CI significantly reduced listening-related fatigue (as well as listening effort, hearing handicap, and social isolation) as soon as 2 weeks post-CI activation. However, the magnitude of fatigue-related issues for both CI candidates and experienced CI users varies widely. Audiologic factors, such as hearing loss severity and aided speech recognition, were not predictive of individual differences in listening-related fatigue. In contrast, strong associations were observed between perceived hearing handicap and listening-related fatigue in all groups suggesting fatigue-related issues may be a component of perceived hearing handicap.

Restoration of auditory function among hearing impaired individuals using Cochlear Implant (CI) technology has contributed significantly towards an improved quality of life. CI users experience greater challenges in recognizing speech effectively in noisy, reverberant, or time-varying diverse environments. Most CI research efforts focus on enhancing speech perception and environmental sound awareness has received little or no attention. This study focuses on a comparative analysis of normal hearing (NH) vs. CI environmental sound recognition using classifiers trained on learned sound representations using a CNN-based sound event model. Sounds experienced by CI listeners are recreated by auralizing electrical stimuli. CCi-MOBILE is used to generate electrical stimuli and Braecker Vocoder is used for auralization. Natural and auralized sound representations are then applied in order to develop NH and CI sound recognition models. Comparative assessment of environmental sound recognition is carried out by analyzing f1-scores and other performance characteristics. Benefits stemming from this research can help CI researchers improve sound recognition performance, develop novel sound processing algorithms, exclusively for environmental sounds, and identify optimal CI electrical stimulation characteristics to enhance sound perception. Among CI users, improvement in environmental sound awareness contributes to improved quality of life.

To compare the identification of safety-relevant environmental sounds between experienced cochlear implant (CI) users and CI candidates. Cross-sectional. A sample of 19 adult, postlingually deaf CI candidates (CI-Cs), 47 experienced CI users (CI-Es), and a control group of 37 age-matched normal-hearing adults were assessed using the Familiar Environmental Sounds Test-Identification (FEST-I). A subset of 11 sounds relevant for safety were selected for analysis in the current study. Analysis of safety-relevant sound identification accuracy revealed no significant difference in safety-relevant environmental sound identification skills between CI-E and CI-C participants, with average scores of 68.1% and 67.9%, respectively. Both performed substantially lower than age-matched normal hearing adults (95.1%). A significant moderate negative correlation (-0.4) was found between safety-relevant sound accuracy and chronological age only in one group, the CI-E group (r = -0.4, P < .005). These findings fail to demonstrate superior performance in safety-relevant environmental sound identification among CI-Es compared with CI-Cs. Although preliminary, these findings suggest that identification of safety-relevant sounds is a significant area of weakness for both CI-Es and CI-Cs, both of whom may benefit from rehabilitation. 4 Laryngoscope, 130:1547-1551, 2020.

Approximately 30% of cochlear implant (CI) users report that restoring their ability to enjoy music is a primary goal. However, music perception in CI users has mostly been investigated in controlled laboratory settings using simplified stimuli, such as pure tones or monophonic melodies. There is an increasing interest in developing objective measures of CI outcomes in everyday listening situations, particularly in music listening, which involves complex stimuli rich in timbre, pitch, rhythm, and overlapping sounds. One promising approach is to measure cortical auditory evoked responses (ERs) in CI users. We investigated whether ERs to sound onsets in a naturalistic four-minute music piece could be measured in adult CI users (N: 25; ages 18-80; CI experience: 0.3-14 years). We assumed that the accumulation of CI experience might be reflected in the morphology of the ERs. The results confirmed that P2 responses to sound onsets embedded in a whole piece of music can be detected in experienced CI users. Compared to a control group with normal hearing, the CI users showed P2 responses with lower amplitudes and longer latencies. Exploratory linear regression models suggested that the logarithmic duration of CI experience significantly predicted both perceived quality of musical sounds and P2 amplitude, explaining 38% and 28% of the variance, respectively. The findings suggest that music perception outcomes may continue to improve for up to 2-4 years post-implantation. Altogether, the results are consistent with the use of ERs to track CI adaptation to music listening.

The purpose of this study was to determine (a) if acceptable noise levels (ANLs) are different in cochlear implant (CI) users than in listeners with normal hearing, (b) if ANLs are related to sentence reception thresholds in noise in CI users, and (c) if ANLs and subjective outcome measures are related in CI users. ANLs and the Hearing in Noise Test (HINT; M. Nilsson, S. Soli, & J. Sullivan, 1994) were examined in 9 adult CI users and 15 adult listeners with normal hearing. In addition, the Abbreviated Profile of Hearing Aid Benefit (APHAB; R. M. Cox & G. C. Alexander, 1995) and a satisfaction questionnaire were administered to CI users only. Results indicated that (a) ANLs were not significantly different for CI users and listeners with normal hearing, (b) ANLs were not correlated with HINT values for either group, (c) ANL was not significantly correlated with APHAB scores, and (d) ANL was significantly correlated with overall CI benefit on the satisfaction questionnaire. CI users with large ANLs reported more benefit from implants than those with small ANLs. The results of this preliminary study of ANL in CI users suggest that ANL can be used as a tool for evaluating processing in noise in individual CI users.

Does cochlear implantation restore music appreciation?

The use of context by individuals with hearing loss has been extensively studied in speech, but not in environmental sound perception. The effect of context on environmental sound perception was investigated in 26 older normal hearing (ONH) and 46 adult postlingual cochlear implant (CI) listeners. Participants first identified 24 individual environmental sounds in isolation and then were presented with the same sounds arranged in 3–5 sound sequences. Half of the sequences were either contextually coherent (i.e., likely to be heard together) and half were incoherent. Results revealed greater accuracy of ONH than CI listeners in identification of isolated environmental sounds. However, no group differences were observed in the identification of sounds sequences. In both groups contextually coherent sequences were identified more accurately than incoherent ones, while accuracy decreased with sequence length. Sequence length interacted with context, with context effect increasing for longer sequences. These findings demonstrate that environmental sound identification remains challenging for CI listeners. Nevertheless, both CI and ONH listeners utilize context to aid in environmental sound identification in perceptually challenging tasks associated with a greater working memory load. Future research may further assess the relationship between environmental sound perception and other ecologically significant aspects of electric hearing.

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Purpose: The current study investigates how individual differences in cochlear implant (CI) users’ sensitivity to word–nonword differences, reflecting lexical uncertainty, relate to their reliance on sentential context for lexical access in processing continuous speech.Method: Fifteen CI users and 14 normal-hearing (NH) controls participated in an auditory lexical decision task (Experiment 1) and a visual-world paradigm task (Experiment 2). Experiment 1 tested participants’ reliance on lexical statistics, and Experiment 2 studied how sentential context affects the time course and patterns of lexical competition leading to lexical access.Results: In Experiment 1, CI users had lower accuracy scores and longer reaction times than NH listeners, particularly for nonwords. In Experiment 2, CI users’ lexical competition patterns were, on average, similar to those of NH listeners, but the patterns of individual CI users varied greatly. Individual CI users’ word–nonword sensitivity (Experiment 1) explained differences in the reliance on sentential context to resolve lexical competition, whereas clinical speech perception scores explained competition with phonologically related words.Conclusions: The general analysis of CI users’ lexical competition patterns showed merely quantitative differences with NH listeners in the time course of lexical competition, but our additional analysis revealed more qualitative differences in CI users’ strategies to process speech. Individuals’ word–nonword sensitivity explained different parts of individual variability than clinical speech perception scores. These results stress, particularly for heterogeneous clinical populations such as CI users, the importance of investigating individual differences in addition to group averages, as they can be informative for clinical rehabilitation.Supplemental Material S1. An overview of the word and nonword characteristics of the stimuli that were used for the auditory lexical decision task (Experiment 1).Supplemental Material S2. Table with the coefficients of the best fitting model of participants’ accuracy scores for the auditory lexical decision task (Experiment 1).Supplemental Material S3. Table with the coefficients of the best fitting model of participants’ reaction times for the auditory lexical decision task (Experiment 1).Supplemental Material S4. Table with the coefficients of the best fitting model for fixations towards the phonological competitor (Experiment 2).Supplemental Material S5. Table with the coefficients of the best fitting model for fixations towards the semantic competitor (Experiment 2).Supplemental Material S6. Table with the coefficients of the best fitting model for fixations towards the phonological competitor by the subgroup of CI users (Experiment 2).Supplemental Material S7. Table with the coefficients of the best fitting model for fixations towards the semantic competitor by the subgroup of CI users (Experiment 2).Nagels, L., Bastiaanse, R., Baskent, D., & Wagner, A. (2019). Individual differences in lexical access among cochlear implant users. Journal of Speech, Language, and Hearing Research. Advance online publication. https://doi.org/10.1044/2019_JSLHR-19-00192

Identification of emotional prosody in speech declines with age in normally hearing (NH) adults. Cochlear implant (CI) users have deficits in the perception of prosody, but the effects of age on vocal emotion recognition by adult postlingually deaf CI users are not known. The objective of the present study was to examine age-related changes in CI users' and NH listeners' emotion recognition. Participants included 18 CI users (29.6 to 74.5 years) and 43 NH adults (25.8 to 74.8 years). Participants listened to emotion-neutral sentences spoken by a male and female talker in five emotions (happy, sad, scared, angry, neutral). NH adults heard them in four conditions: unprocessed (full spectrum) speech, 16-channel, 8-channel, and 4-channel noise-band vocoded speech. The adult CI users only listened to unprocessed (full spectrum) speech. Sensitivity (d') to emotions and Reaction Times were obtained using a single-interval, five-alternative, forced-choice paradigm. For NH participants, results indicated age-related declines in Accuracy and d', and age-related increases in Reaction Time in all conditions. Results indicated an overall deficit, as well as age-related declines in overall d' for CI users, but Reaction Times were elevated compared with NH listeners and did not show age-related changes. Analysis of Accuracy scores (hit rates) were generally consistent with d' data. Both CI users and NH listeners showed age-related deficits in emotion identification. The CI users' overall deficit in emotion perception, and their slower response times, suggest impaired social communication which may in turn impact overall well-being, particularly so for older CI users, as lower vocal emotion recognition scores have been associated with poorer subjective quality of life in CI patients.

Cochlear implant (CI) users face difficulties in accurately perceiving basic musical elements such as pitch, melody, and timbre. Music significantly affects the quality of life (QoL) of CI users. Individually and culturally influenced music perception exceeds psychophysical measures in capturing the subjective music enjoyment of CI users. Understanding the music perception, enjoyment, and habits of CI users is crucial for approaches to improve music-related QoL (MuRQoL). Therefore, this study aims to investigate music perception skills, experiences, and participation in music activities in a large group of adult CI users, and to understand the importance of these factors and their impact on QoL of CI users. This study included 214 CI recipients with diverse auditory experiences who were aged between 18 and 65 years and were unilateral, bimodal, or bilateral users for at least 1 year and 193 normal hearing (NH) controls. All participants completed the information forms and the MuRQoL questionnaire. To assess the impact of music on QoL and identify personalized rehabilitation needs, the scores for each question in both parts of the questionnaire were intersected on a matrix. Data were presented in detail for the CI group and compared between CI and NH groups. A statistically significant difference was found between the matched CI and NH groups in favor of the NH group in terms of music perception and music engagement. Participants who received music education at any point in their lives had significantly higher MuRQoL questionnaire scores. There was no significant relationship found between the duration of auditory rehabilitation, pre-CI hearing aid usage, music listening modality, and MuRQoL questionnaire scores. Unilateral CI users had significantly lower scores in music perception and music engagement subsections compared with bimodal and bilateral CI users. Also, it was found that music had a strong negative impact on QoL in 67/214 of the CI users. Although CI users scored significantly lower than NH individuals on the first part of the questionnaire, which asked about musical skills, enjoyment, and participation in musical activities, findings suggest that CI users value music and music enjoyment just as much. The study reveals the influence of factors such as education level, age, music education, type of hearing loss and auditory rehabilitation on music perception, music enjoyment, and participation in music activities through self-report. The results indicate that for many CI users, music has a strong negative impact on QoL, highlighting the need for personalized music interventions, the inclusion of self-report questionnaires, and music perception tests in clinical evaluations.

It has been theorized that neural recovery is related to temporal coding of speech sounds. The recovery function of cortically generated auditory evoked potentials has not been investigated in cochlear implant (CI) users. This study characterized the recovery function of the late auditory evoked potential (LAEP) using a masker-probe paradigm in postlingually deafened adult CI users and young normal-hearing (NH) listeners. A case-control study of the late auditory evoked potentials using electrophysiological technique was performed. The LAEP was evoked by 1 kHz tone bursts presented in pairs, with the first stimuli as the maskers and the second stimuli as the probes. The masker-probe intervals (MPIs) were varied at 0.7, 1, 2, 4, and 8 sec, with an interpair interval of 12 sec. Nine CI users and nine NH listeners participated in this study. The normalized amplitude from the probe response relative to the masker response was plotted as a function of the MPI to form a recovery function. The latency shift for the probe response relative to the masker response was calculated. The recovery function was approximately linear in log scale of the MPI in NH listeners, while it showed somewhat different recovery patterns with a large intersubject variability in CI users. Specifically, although the probe response was approximately 60 percent of the masker response for the MPI of 0.7 sec in both groups, the recovery function of CI users displayed a nonlinear pattern, with a steeper slope than that of NH listeners. The probe response completely recovered at the MPI of 4 sec in NH listeners and at the MPI of 2 sec in CI users. N1 and P2 latencies from probe responses were shorter than those from masker responses in NH listeners, while no latency difference was found between probe responses and masker responses in CI users. Our interpretation of these findings is that the faster recovery of the LAEP in CI users is related to abnormal adaptation mechanisms and a less prominent role of the components with longer latencies in the LAEP of CI users. Other mechanisms such as the compromised inhibitory regulation in the auditory system and the aging effect in CI users might also play a role. More research needs to be done to determine whether the slope of the LAEP recovery function is correlated with speech-perception performance.