DSpace Angular :: Browsing by Author "Marozeau, Jeremy"

Browsing by Author "Marozeau, Jeremy"

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The acoustic and perceptual cues affecting melody segregation for listeners with a cochlear implant
(Frontiers, 2013-10) Marozeau, Jeremy; Innes-Brown, Hamish; Blamey, Peter
Our ability to listen selectively to single sound sources in complex auditory environments is termed “auditory stream segregation.” This ability is affected by peripheral disorders such as hearing loss, as well as plasticity in central processing such as occurs with musical training. Brain plasticity induced by musical training can enhance the ability to segregate sound, leading to improvements in a variety of auditory abilities. The melody segregation ability of 12 cochlear-implant recipients was tested using a new method to determine the perceptual distance needed to segregate a simple 4-note melody from a background of interleaved random-pitch distractor notes. In experiment 1, participants rated the difficulty of segregating the melody from distracter notes. Four physical properties of the distracter notes were changed. In experiment 2, listeners were asked to rate the dissimilarity between melody patterns whose notes differed on the four physical properties simultaneously. Multidimensional scaling analysis transformed the dissimilarity ratings into perceptual distances. Regression between physical and perceptual cues then derived the minimal perceptual distance needed to segregate the melody. The most efficient streaming cue for CI users was loudness. For the normal hearing listeners without musical backgrounds, a greater difference on the perceptual dimension correlated to the temporal envelope is needed for stream segregation in CI users. No differences in streaming efficiency were found between the perceptual dimensions linked to the F0 and the spectral envelope. Combined with our previous results in normally-hearing musicians and non-musicians, the results show that differences in training as well as differences in peripheral auditory processing (hearing impairment and the use of a hearing device) influences the way that listeners use different acoustic cues for segregating interleaved musical streams.
Auditory Stream Segregation and Selective Attention for Cochlear Implant Listeners: Evidence From Behavioral Measures and Event-Related Potentials
(Frontiers in Neuroscience, 2018-08) Paredes-Gallardo, Andreu; Innes-Brown, Hamish; Madsen, Sara; Dau, Torsten; Marozeau, Jeremy
The role of the spatial separation between the stimulating electrodes (electrode separation) in sequential stream segregation was explored in cochlear implant (CI) listeners using a deviant detection task. Twelve CI listeners were instructed to attend to a series of target sounds in the presence of interleaved distractor sounds. A deviant was randomly introduced in the target stream either at the beginning, middle or end of each trial. The listeners were asked to detect sequences that contained a deviant and to report its location within the trial. The perceptual segregation of the streams should, therefore, improve deviant detection performance. The electrode range for the distractor sounds was varied, resulting in different amounts of overlap between the target and the distractor streams. For the largest electrode separation condition, event-related potentials (ERPs) were recorded under active and passive listening conditions. The listeners were asked to perform the behavioral task for the active listening condition and encouraged to watch a muted movie for the passive listening condition. Deviant detection performance improved by increasing electrode separation between the streams, suggesting that larger electrode differences facilitate the segregation of the streams. Deviant detection performance was best for deviants happening late in the sequence, indicating that a segregated percept builds up over time. The analysis of the ERP waveforms revealed that auditory selective attention modulates the ERP responses in CI listeners. Specifically, the responses to the target stream were, overall, larger in the active relative to the passive listening condition. Conversely, the ERP responses to the distractor stream were not affected by selective attention. However, no significant correlation was observed between the behavioral performance and the amount of attentional modulation. Overall, the findings from the present study suggest that CI listeners can use electrode separation to perceptually group sequential sounds. Moreover, selective attention can be deployed on the basis of the resulting auditory objects, as reflected by the attentional modulation of the ERPs at the group level.
A bilateral cochlear implant user with exceptional musical hearing ability
(Informa Healthcare, 2013-06) Maarefvand, Mohammad; Marozeau, Jeremy; Blamey, Peter
Although the perception of music is generally poor in cochlear implant users, there are a few excellent performers. Objective: The aim of this study was the assessment of different aspects of music perception in one exceptional cochlear implant user. Design: The assessments included pitch direction discrimination, melody and timbre recognition, relative and absolute pitch judgment and consonance rating of musical notes presented through the sound processor(s). Study sample: An adult cochlear implant user with musical background who lost her hearing postlingually, and five normally hearing listeners with musical training participated in the study. Results: The CI user discriminated pitch direction for sounds differing by one semitone and recognized melody with nearly 100% accuracy. Her results in timbre recognition were better than average published data for cochlear implant users. Her consonance rating, and relative and absolute pitch perception were comparable to normal hearing listeners with musical training. Conclusion: The results in this study are an “existence proof” that excellent performance is possible on musical perception tasks including pitch perception using present day cochlear implant technologies. Factors that may explain this user’s exceptional performance are short duration of deafness, pre and post deafness musical training and perfect pitch abilities before the onset of deafness.
Dichotic Listening Can Improve Perceived Clarity of Music in Cochlear Implant Users
(SAGE, 2015-09) Vannson, Nicolas; Innes-Brown, Hamish; Marozeau, Jeremy
Musical enjoyment for cochlear implant (CI) recipients is often reported to be unsatisfactory. Our goal was to determine whether the musical experience of postlingually deafened adult CI recipients could be enriched by presenting the bass and treble clef parts of short polyphonic piano pieces separately to each ear (dichotic). Dichotic presentation should artificially enhance the lateralization cues of each part and help the listeners to better segregate them and thus provide greater clarity. We also hypothesized that perception of the intended emotion of the pieces and their overall enjoyment would be enhanced in the dichotic mode compared with the monophonic (both parts in the same ear) and the diotic mode (both parts in both ears). Twenty-eight piano pieces specifically composed to induce sad or happy emotions were selected. The tempo of the pieces, which ranged from lento to presto covaried with the intended emotion (from sad to happy). Thirty participants (11 normal-hearing listeners, 11 bimodal CI and hearing-aid users, and 8 bilaterally implanted CI users) participated in this study. Participants were asked to rate the perceived clarity, the intended emotion, and their preference of each piece in different listening modes. Results indicated that dichotic presentation produced small significant improvements in subjective ratings based on perceived clarity and preference. We also found that preference and clarity ratings were significantly higher for pieces with fast tempi compared with slow tempi. However, no significant differences between diotic and dichotic presentation were found for the participants' preference ratings, or their judgments of intended emotion.
The effect of timbre and loudness on melody segregation
(the Regents of the University of California., 2013-02) Marozeau, Jeremy; Innes-Brown, Hamish; Blamey, Peter
THE AIM OF THIS STUDY WAS TO EXAMINE THE effects of three acoustic parameters on the difficulty of segregating a simple 4-note melody from a background of interleaved distractor notes. Melody segregation difficulty ratings were recorded while three acoustic para- meters of the distractor notes were varied separately: intensity, temporal envelope, and spectral envelope. Statistical analyses revealed a significant effect of music training on difficulty rating judgments. For participants with music training, loudness was the most efficient perceptual cue, and no difference was found between the dimensions of timbre influenced by temporal and spectral envelope. For the group of listeners with less music training, both loudness and spectral envelope were the most efficient cues. We speculate that the dif- ference between musicians and nonmusicians may be due to differences in processing the stimuli: musicians may process harmonic sound sequences using brain networks specialized for music, whereas nonmusicians may use speech networks.
The effect of visual cues on difficulty ratings for segregation of musical streams in listeners with impaired hearing
(PLOS, 2011-12-15) Innes-Brown, Hamish; Marozeau, Jeremy; Blamey, Peter
Background: Enjoyment of music is an important part of life that may be degraded for people with hearing impairments, especially those using cochlear implants. The ability to follow separate lines of melody is an important factor in music appreciation. This ability relies on effective auditory streaming, which is much reduced in people with hearing impairment, contributing to difficulties in music appreciation. The aim of this study was to assess whether visual cues could reduce the subjective difficulty of segregating a melody from interleaved background notes in normally hearing listeners, those using hearing aids, and those using cochlear implants. Methodology/Principal Findings: Normally hearing listeners (N = 20), hearing aid users (N = 10), and cochlear implant users (N = 11) were asked to rate the difficulty of segregating a repeating four-note melody from random interleaved distracter notes. The pitch of the background notes was gradually increased or decreased throughout blocks, providing a range of difficulty from easy (with a large pitch separation between melody and distracter) to impossible (with the melody and distracter completely overlapping). Visual cues were provided on half the blocks, and difficulty ratings for blocks with and without visual cues were compared between groups. Visual cues reduced the subjective difficulty of extracting the melody from the distracter notes for normally hearing listeners and cochlear implant users, but not hearing aid users. Conclusion/Significance: Simple visual cues may improve the ability of cochlear implant users to segregate lines of music, thus potentially increasing their enjoyment of music. More research is needed to determine what type of acoustic cues to encode visually in order to optimise the benefits they may provide.
‘Like Pots and Pans Falling Down the Stairs’. Experience of Music Composed for Listeners with Cochlear Implants in a Live Concert Setting
(Routledge, 2014-06-12) Schubert, Emery; Marozeau, Jeremy; Stevens, Catherine; Innes-Brown, Hamish
This study investigated whether music specially written for people with cochlear implants (CIs) could be used to better pinpoint how the music listening experience for a CI was different to a normal hearing listener (NH). After the specially arranged live concert, focus groups were formed from audience volunteers (two groups each of CIs, NHs and people with a range of hearing assistant devices). The theme of musical features (MF) was reported most frequently for both NHs and CIs. Valence analysis identified no significant difference in positive comments aboutMFby CIs thanNHsfor the specially commissioned works. Spatialization, although reported infrequently, was considered important by some CI, NH and bimodal listeners (who use a cochlear implant and a hearing aid). Rhythm was enjoyed by both NH and CI groups, and percussion instruments liked more than other musical instruments, but more so by CIs. Bilateral and bimodal CIs expressed interest in optimizing the hearing assistance settings, but on several occasions, the optimization ended with turning the contralateral hearing aid off. The study identifies the possible critical role of familiarity in music enjoyment.
Music for the cochlear implant: Audience response to six commissioned compositions.
(Thieme Medical Publishers, 2012-11) Au, Agnes; Marozeau, Jeremy; Innes-Brown, Hamish; Schubert, Emery; Stevens, Catherine
Although cochlear implant (CI) users enjoy good speech understanding, music perception is still difficult or unpleasant for many. This study aimed to assess cognitive, engagement, and auditory responses to new music composed specifically for CI users. From 407 concertgoers who completed a questionnaire, responses from groups of normally hearing listeners (n = 44) and CI users (n = 44), matched in age and musical ability, were compared to determine whether specially commissioned works would elicit similar responses from both groups. No significant group differences were found on measures of interest, enjoyment, and musicality, whereas ratings of understanding and instrument localization and recognition were significantly lower for CI users. Overall, ratings of the music were typically higher for percussion pieces. The concert successfully elicited similar responses from both groups in terms of interest, enjoyment, and musicality, although technical aspects, such as understanding, localization, and instrument identification, continue to be problematic for CI users.
Perceptual Interactions Between Electrodes Using Focused and Monopolar Cochlear Stimulation
(Springer US, 2015-03-06) Marozeau, Jeremy; McDermott, Hugh; Swanson, Brett; McKay, Colette
In today’s cochlear implant (CI) systems, the monopolar (MP) electrode configuration is the most commonly used stimulation mode, requiring only a single current source. However, with an implant that will allow simultaneous activation of multiple independent current sources, it is possible to implement an all-polar (AP) stimulation mode designed to create a focused electrical field. The goal of this experiment was to study the potential benefits of this all-polar mode for reducing uncontrolled electrode interactions compared with the monopolar mode. The five participants who took part in the study were implanted with a research device that was connected via a percutaneous connector to a benchtop stimulator providing 22 independent current sources. The perceptual effects of the AP mode were tested in three experiments. In Experiment 1, the current level difference between loudness-matched sequential and simultaneous stimuli composed of 2 spatially separated pulse trains was measured as function of the electrode separation. Results indicated a strong current-summation interaction for simultaneous stimuli in the MP mode for separations up to at least 4.8 mm. No significant interaction was found in the AP mode beyond a separation of 2.4 mm. In Experiment 2, a forward-masking paradigm was used with fixed equally loud probes in AP and MP modes, and AP maskers presented on different electrode positions. Results indicated a similar spatial masking pattern between modes. In Experiment 3, subjects were asked to discriminate between across-electrode temporal delays. It was hypothesized that discrimination would decrease with electrode separation faster in AP compared to MP modes. However, results showed no difference between the two modes. Overall, the results indicated that the AP mode produced less current spread than MP mode but did not lead to a significant advantage in terms of spread of neuronal excitation at equally loud levels.
Perceptual Spaces Induced by Cochlear Implant All-Polar Stimulation Mode
(Sage Journals, 2016-06) McKay, Colette; Marozeau, Jeremy
It has been argued that a main limitation of the cochlear implant is the spread of current induced by each electrode, which activates an inappropriately large range of sensory neurons. To reduce this spread, an alternative stimulation mode, the all-polar mode, was tested with five participants. It was designed to activate all the electrodes simultaneously with appropriate current levels and polarities to recruit narrower regions of auditory nerves at specific intracochlear electrode positions (denoted all-polar electrodes). In this study, the all-polar mode was compared with the current commercial stimulation mode: the monopolar mode. The participants were asked to judge the sound dissimilarity between pairs of two-electrode pulse-train stimuli that differed in the electrode positions and were presented in either monopolar or all-polar mode with pulses on the two electrodes presented either sequentially or simultaneously. The dissimilarity ratings were analyzed using a multidimensional scaling technique and three-dimensional stimulus perceptual spaces were produced. For all the conditions (mode and simultaneity), the first perceptual dimension was highly correlated with the position of the most apical activated electrode of the electrical stimulation and the second dimension with the position of the most basal electrode. In both sequential and simultaneous conditions, the monopolar and all-polar stimuli were significantly separated by a third dimension, which may indicate that all-polar stimuli have a perceptual quality that differs from monopolar stimuli. Overall, the results suggest that both modes might successfully represent spectral information in a sound processing strategy
Pitch matching in bimodal cochlear implant patients: Effects of frequency, spectral envelope, and level
(Acoustical Society of America, 2017-11) Maarefvand, Mohammad; Blamey, Peter; Marozeau, Jeremy
This study systematically investigated the effects of frequency, level, and spectral envelope on pitch matching in twelve bimodal cochlear implant (CI) users. The participants were asked to vary the frequency and level of a pure or complex tone (adjustable sounds) presented in the nonimplanted ear to match the pitch and loudness of different reference stimuli presented to the implanted ear. Three reference sounds were used: single electrode pulse trains, pure tones, and piano notes. The data showed a significant effect of the frequency and complexity of the reference sounds. No significant effect of the level of the reference sounds was found. The magnitude of effect of frequency was compressed in the implanted ear: on average a difference of seven semitones in the non-implanted ear induced the same pitch change as a difference of 19 to 24 semitones for a stimulus presented to the implanted ear. The spectral envelope of the adjustable sound presented to the non-implanted ear also had a significant effect. The matched frequencies were higher by an average of six semitones for the pure tone compared to a complex tone. Overall, the CI listeners might have matched the stimuli based on timbre characteristics such as brightness.
The sound sensation of apical electric stimulation in cochlear implant recipients with contralateral residual hearing
(PLoS One, 2012-06-19) Lazard, Diane; Marozeau, Jeremy; McDermott, Hugh
Background: Studies using vocoders as acoustic simulators of cochlear implants have generally focused on simulation of speech understanding, gender recognition, or music appreciation. The aim of the present experiment was to study the auditory sensation perceived by cochlear implant (CI) recipients with steady electrical stimulation on the most-apical electrode. Methodology/Principal Findings: Five unilateral CI users with contralateral residual hearing were asked to vary the parameters of an acoustic signal played to the non-implanted ear, in order to match its sensation to that of the electric stimulus. They also provided a rating of similarity between each acoustic sound they selected and the electric stimulus. On average across subjects, the sound rated as most similar was a complex signal with a concentration of energy around 523 Hz. This sound was inharmonic in 3 out of 5 subjects with a moderate, progressive increase in the spacing between the frequency components. Conclusions/Significance: For these subjects, the sound sensation created by steady electric stimulation on the most-apical electrode was neither a white noise nor a pure tone, but a complex signal with a progressive increase in the spacing between the frequency components in 3 out of 5 subjects. Knowing whether the inharmonic nature of the sound was related to the fact that the non-implanted ear was impaired has to be explored in single-sided deafened patients with a contralateral CI. These results may be used in the future to better understand peripheral and central auditory processing in relation to cochlear implants.
Towards Objective Measures of Functional Hearing Abilities
(Springer International Publishing, 2016-04) Innes-Brown, Hamish; Tsongas, Renee; Marozeau, Jeremy; McKay, Colette
Aims People with impaired hearing often have difficulties in hearing sounds in a noisy background. This problem is partially a result of the auditory systems reduced capacity to process temporal information in the sound signal. In this study we examined the relationships between perceptual sensitivity to temporal fine structure (TFS) cues, brainstem encoding of complex harmonic and amplitude modulated sounds, and the ability to understand speech in noise. Understanding these links will allow the development of an objective measure that could be used to detect changes in functional hearing before the onset of permanent threshold shifts. Methods We measured TFS sensitivity and speech in noise performance (QuickSIN) behaviourally in 34 normally hearing adults with ages ranging from 18 to 63 years. We recorded brainstem responses to complex harmonic sounds and a 4000 Hz carrier signal modulated at 110 Hz. We performed cross correlations between the stimulus waveforms and scalp-recorded brainstem responses to generate a simple measure of stimulus encoding accuracy, and correlated these measures with age, TFS sensitivity and speech-in-noise performance. Results Speech-in-noise performance was positively correlated with TFS sensitivity, and negatively correlated with age. TFS sensitivity was also positively correlated with stimulus encoding accuracy for the complex harmonic stimulus, while increasing age was associated with lower stimulus encoding accuracy for the modulated tone stimulus. Conclusions The results show that even in a group of people with normal hearing, increasing age was associated with reduced speech understanding, reduced TFS sensitivity, and reduced stimulus encoding accuracy (for the modulated tone stimulus). People with good TFS sensitivity also generally had less faithful brainstem encoding of a complex harmonic tone.

Browsing by Author "Marozeau, Jeremy"

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