Musical Perception and Enjoyment in Post-Lingual Patients With Cochlear Implants

Experience with the cochlear implant enhances the neural tracking of spectrotemporal patterns in the Alberti bass

Cochlear implant (CI) users experience diminished music enjoyment due to the technical limitations of the CI. Nonetheless, behavioral studies have reported that rhythmic features are well-transmitted through the CI. Still, the gradual improvement of rhythm perception after the CI switch-on has not yet been determined using neurophysiological measures. To fill this gap, we here reanalyzed the electroencephalographic responses of participants from two previous mismatch negativity studies. These studies included eight recently implanted CI users measured twice, within the first six weeks after CI switch-on and approximately three months later; thirteen experienced CI users with a median experience of 7 years; and fourteen normally hearing (NH) controls. All participants listened to a repetitive four-tone pattern (known in music as Alberti bass) for 35 min. Applying frequency tagging, we aimed to estimate the neural activity synchronized to the periodicities of the Alberti bass. We hypothesized that longer experience with the CI would be reflected in stronger frequency-tagged neural responses approaching the responses of NH controls. We found an increase in the frequency-tagged amplitudes after only 3 months of CI use. This increase in neural synchronization may reflect an early adaptation to the CI stimulation. Moreover, the frequency-tagged amplitudes of experienced CI users were significantly greater than those of recently implanted CI users, but still smaller than those of NH controls. The frequency-tagged neural responses did not just reflect spectrotemporal changes in the stimuli (i.e., intensity or spectral content fluctuating over time), but also showed non-linear transformations that seemed to enhance relevant periodicities of the Alberti bass. Our findings provide neurophysiological evidence indicating a gradual adaptation to the CI, which is noticeable already after three months, resulting in close to NH brain processing of spectrotemporal features of musical rhythms after extended CI use.

A Concert-Based Study on Melodic Contour Identification among Varied Hearing Profiles-A Preliminary Report

Background: This study investigated how different hearing profiles influenced melodic contour identification (MCI) in a real-world concert setting with a live band including drums, bass, and a lead instrument. We aimed to determine the impact of various auditory assistive technologies on music perception in an ecologically valid environment. Methods: The study involved 43 participants with varying hearing capabilities: normal hearing, bilateral hearing aids, bimodal hearing, single-sided cochlear implants, and bilateral cochlear implants. Participants were exposed to melodies played on a piano or accordion, with and without an electric bass as a masker, accompanied by a basic drum rhythm. Bayesian logistic mixed-effects models were utilized to analyze the data. Results: The introduction of an electric bass as a masker did not significantly affect MCI performance for any hearing group when melodies were played on the piano, contrary to its effect on accordion melodies and previous studies. Greater challenges were observed with accordion melodies, especially when accompanied by an electric bass. Conclusions: MCI performance among hearing aid users was comparable to other hearing-impaired profiles, challenging the hypothesis that they would outperform cochlear implant users. A cohort of short melodies inspired by Western music styles was developed for future contour identification tasks.

The Impact of Vocal Boost Manipulations on Musical Sound Quality for Cochlear Implant Users

OBJECTIVE

To evaluate the impact of vocal boost manipulations on cochlear implant (CI) musical sound quality appraisals.

METHODS

An anonymous, online study was distributed to 33 CI users. Participants listened to auditory tokens and assessed the musical quality of acoustic stimuli with vocal boosting and attenuation using a validated sound quality rating scale. Four versions of real-world musical stimuli were created: a version with +9 dB vocal boost, a version with -9 dB vocal attenuation, a composite stimulus containing a 1,000 Hz low-pass filter and white noise ("anchor"), and an unaltered version ("hidden reference"). Subjects listened to all four versions and provided ratings based on a 100-point scale that reflected the perceived sound quality difference of the music clip relative to the reference excerpt.

RESULTS

Vocal boost increased musical sound quality ratings relative to the reference clip (11.7; 95% CI, 1.62-21.8, p = 0.016) and vocal attenuation decreased musical sound quality ratings relative to the reference clip (28.5; 95% CI, 18.64-38.44, p < 0.001). When comparing the non-musical training group and musical training group, there was a significant difference in musical sound quality rating scores for the vocal boost condition (21.2; 95% CI: 1.76-40.7, p = 0.028).

CONCLUSIONS

CI-mediated musical sound quality appraisals are impacted by vocal boost and attenuation. Musically trained CI users to report greater musical sound quality enhancement with a vocal boost with respect to CI users with no musical training background. Implementation of front-end vocal boost manipulations in music may improve sound quality and music appreciation among CI users.

LEVEL OF EVIDENCE

2 (Individual cohort study) Laryngoscope, 133:938-947, 2023.

Musical Emotion Categorization with Vocoders of Varying Temporal and Spectral Content

While previous research investigating music emotion perception of cochlear implant (CI) users observed that temporal cues informing tempo largely convey emotional arousal (relaxing/stimulating), it remains unclear how other properties of the temporal content may contribute to the transmission of arousal features. Moreover, while detailed spectral information related to pitch and harmony in music - often not well perceived by CI users- reportedly conveys emotional valence (positive, negative), it remains unclear how the quality of spectral content contributes to valence perception. Therefore, the current study used vocoders to vary temporal and spectral content of music and tested music emotion categorization (joy, fear, serenity, sadness) in 23 normal-hearing participants. Vocoders were varied with two carriers (sinewave or noise; primarily modulating temporal information), and two filter orders (low or high; primarily modulating spectral information). Results indicated that emotion categorization was above-chance in vocoded excerpts but poorer than in a non-vocoded control condition. Among vocoded conditions, better temporal content (sinewave carriers) improved emotion categorization with a large effect while better spectral content (high filter order) improved it with a small effect. Arousal features were comparably transmitted in non-vocoded and vocoded conditions, indicating that lower temporal content successfully conveyed emotional arousal. Valence feature transmission steeply declined in vocoded conditions, revealing that valence perception was difficult for both lower and higher spectral content. The reliance on arousal information for emotion categorization of vocoded music suggests that efforts to refine temporal cues in the CI user signal may immediately benefit their music emotion perception.

Musical Perception Assessment of People With Hearing Impairment: A Systematic Review and Meta-Analysis

Purpose People with hearing impairment (HI) face numerous challenges that can be minimized with the use of hearing aids and cochlear implants. Despite technological advances in these assistive hearing devices, musical perception remains difficult for these people. Tests and protocols developed to assess the musical perception of this audience were the target of this systematic review, whose objective was to investigate how assessments of musical perception in people with HI are carried out. Method Searches for primary articles were carried out in the PubMed/MEDLINE, Scopus, Web of Science, Latin American and Caribbean Health Sciences Literature, and ASHAWire databases. Search results were managed using EndNote X9 software, and analysis was performed according to the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) Statement. Results The 16 cross-sectional included studies analyzed music perception data from people with HI compared to a control group of participants with normal hearing. Among these, four studies were selected to be included in a meta-analysis, performed with timbre and melody. Variability was observed in the tests and between the levels of auditory perception skills analyzed in relation to the components of music. With respect to the tests, sound stimuli generated by synthesizers were the most used stimuli; with the exception of timbre evaluation, the most frequent test environment was a booth with sound attenuation, and the average intensity for presenting sound stimuli was 70 dB SPL. The most evaluated sound component was pitch, followed by rhythm and timbre, with a pattern of responses based on adaptive and psychoacoustic methods. Conclusions The heterogeneity of the musical parameters and the auditory abilities evaluated by the tests is a fact that can compromise evidence found in this area of study. It is worth considering the quality of samples that were recorded with real musical instruments and digitized afterward, in comparison with synthesized samples that do not seem to accurately represent real instruments. The need to minimize semantic parallelism that involves the auditory skills and elements of music involved in the assessment of musical perception is highlighted.

Early Deafened, Late Implanted Cochlear Implant Users Appreciate Music More Than and Identify Music as Well as Postlingual Users

Introduction: Typical cochlear implant (CI) users, namely postlingually deafened and implanted, report to not enjoy listening to music, and find it difficult to perceive music. Another group of CI users, the early-deafened (during language acquisition) and late-implanted (after a long period of auditory deprivation; EDLI), report a higher music appreciation, but is this related to a better music perception?

Materials and Methods: Sixteen EDLI and fifteen postlingually deafened (control group) CI users participated in the study. The inclusion criteria for EDLI were: severe or profound hearing loss onset before the age of 6 years, implantation after the age of 16 years, and CI experience more than 1 year. Subjectively, music perception and appreciation was evaluated using the Dutch Musical Background Questionnaire. Behaviorally, music perception was measured with melodic contour identification (MCI), using two instruments (piano and organ), each tested with and without a masking contour. Semitone distance between successive tones of the target varied from 1 to 3 semitones.

Results: Subjectively, the EDLI group reported to appreciate music more than postlingually deafened CI users. Behaviorally, while clinical phoneme recognition test score on average was lower in the EDLI group, melodic contour identification did not significantly differ between the two groups. There was, however, an effect of instrument and masker for both groups; the piano was the best-recognized instrument, and for both instruments, the masker with non-overlapping pitch was best recognized.

Discussion: EDLI group reported higher appreciation of music than postlingual control group, even though behaviorally measured music perception did not differ significantly between the two groups. Both surprising findings since EDLI CI users would be expected to have lower outcomes based on the early deafness onset, long duration of auditory deprivation, and on average lower clinical speech scores. Perhaps, the music perception difficulty comes from similar electric hearing limitations in both groups. The higher subjective appreciation in EDLI might be due to the lack of a musical memory, with no ability to compare music heard via the CI to acoustic music perception. Overall, our findings support a benefit from implantation for a positive music experience in EDLI CI users.

Musical Sound Quality as a Function of the Number of Channels in Modern Cochlear Implant Recipients

Objectives

This study examined musical sound quality (SQ) in adult cochlear implant (CI) recipients. The study goals were to determine: the number of channels needed for high levels of musical SQ overall and by musical genre; the impact of device and patient factors on musical SQ ratings; and the relationship between musical SQ, speech recognition, and speech SQ to relate these findings to measures frequently used in clinical protocols.

Methods

Twenty-one post-lingually deafened adult CI recipients participated in this study. Electrode placement, including scalar location, average electrode-to-modiolus distance (M¯), and angular insertion depth were determined by CT imaging using validated CI position analysis algorithms (e.g., Noble et al., 2013; Zhao et al., 2018, 2019). CI programs were created using 4–22 electrodes with equal spatial distribution of active electrodes across the array. Speech recognition, speech SQ, music perception via a frequency discrimination task, and musical SQ were acutely assessed for all electrode conditions. Musical SQ was assessed using pre-selected musical excerpts from a variety of musical genres.

Results

CI recipients demonstrated continuous improvement in qualitative judgments of musical SQ with up to 10 active electrodes. Participants with straight electrodes placed in scala tympani (ST) and pre-curved electrodes with higher M¯ variance reported higher levels of musical SQ; however, this relationship is believed to be driven by levels of musical experience as well as the potential for preoperative bias in device selection. Participants reported significant increases in musical SQ beyond four channels for all musical genres examined in the current study except for Hip Hop/Rap. After musical experience outliers were removed, there was no relationship between musical experience or frequency discrimination ability and musical SQ ratings. There was a weak, but significant correlation between qualitative ratings for speech stimuli presented in quiet and in noise and musical SQ.

Conclusion

Modern CI recipients may need more channels for musical SQ than even required for asymptotic speech recognition or speech SQ. These findings may be used to provide clinical guidance for personalized expectations management of music appreciation depending on individual device and patient factors.

Comparison of Two Music Training Approaches on Music and Speech Perception in Cochlear Implant Users

In normal-hearing (NH) adults, long-term music training may benefit music and speech perception, even when listening to spectro-temporally degraded signals as experienced by cochlear implant (CI) users. In this study, we compared two different music training approaches in CI users and their effects on speech and music perception, as it remains unclear which approach to music training might be best. The approaches differed in terms of music exercises and social interaction. For the pitch/timbre group, melodic contour identification (MCI) training was performed using computer software. For the music therapy group, training involved face-to-face group exercises (rhythm perception, musical speech perception, music perception, singing, vocal emotion identification, and music improvisation). For the control group, training involved group nonmusic activities (e.g., writing, cooking, and woodworking). Training consisted of weekly 2-hr sessions over a 6-week period. Speech intelligibility in quiet and noise, vocal emotion identification, MCI, and quality of life (QoL) were measured before and after training. The different training approaches appeared to offer different benefits for music and speech perception. Training effects were observed within-domain (better MCI performance for the pitch/timbre group), with little cross-domain transfer of music training (emotion identification significantly improved for the music therapy group). While training had no significant effect on QoL, the music therapy group reported better perceptual skills across training sessions. These results suggest that more extensive and intensive training approaches that combine pitch training with the social aspects of music therapy may further benefit CI users.

Tradução e Adaptação Transcultural para o Português Brasileiro do Questionário Hearing Implant Sound Quality Index - (HISQUI19)

RESUMO Objetivo Traduzir e adaptar transculturalmente o instrumento HISQUI19 (Hearing Implant Sound Quality Index), e caracterizar a população e o desempenho auditivo em usuários de Implante Coclear (IC) pela aplicação da versão síntese. Método Realizou-se a avaliação das equivalências conceitual, de item, semântica e operacional. A versão síntese foi aplicada como um pré-teste que contou com 33 sujeitos no resultado final, caracterizando a amostra e o desempenho do questionário. Os resultados foram analisados estatisticamente. Resultado A tradução final (TF) foi retrotraduzida e comparada à versão original, mostrando diferença mínima entre itens, e as modificações da TF para a versão síntese caracterizaram-se pela aplicação de vocabulário simplificado utilizado no cotidiano. No pré-teste, o escore médio entre os entrevistados foi de 90,2 e confirmou-se alto grau de confiabilidade interna (0,83). Conclusão A tradução e a adaptação do questionário HISQUI19 mostraram adequação para as equivalências semântica, cultural, conceitual e de item. Na caracterização da amostra, a qualidade de som foi classificada como boa com melhor desempenho nas categorias de localização e distinção de sons/vozes.