Christina Fuller

Normal-Hearing Listeners’ and Cochlear Implant Users’ Perception of Pitch Cues in Emotional Speech

In cochlear implants (CIs), acoustic speech cues, especially for pitch, are delivered in a degraded form. This study’s aim is to assess whether due to degraded pitch cues, normal-hearing listeners and CI users employ different perceptual strategies to recognize vocal emotions, and, if so, how these differ. Voice actors were recorded pronouncing a nonce word in four different emotions: anger, sadness, joy, and relief. These recordings’ pitch cues were phonetically analyzed. The recordings were used to test 20 normal-hearing listeners’ and 20 CI users’ emotion recognition. In congruence with previous studies, high-arousal emotions had a higher mean pitch, wider pitch range, and more dominant pitches than low-arousal emotions. Regarding pitch, speakers did not differentiate emotions based on valence but on arousal. Normal-hearing listeners outperformed CI users in emotion recognition, even when presented with CI simulated stimuli. However, only normal-hearing listeners recognized one particular actor’s emotions worse than the other actors’. The groups behaved differently when presented with similar input, showing that they had to employ differing strategies. Considering the respective speaker’s deviating pronunciation, it appears that for normal-hearing listeners, mean pitch is a more salient cue than pitch range, whereas CI users are biased toward pitch range cues.

Gender Categorization Is Abnormal in Cochlear Implant Users

In normal hearing (NH), the perception of the gender of a speaker is strongly affected by two anatomically related vocal characteristics: the fundamental frequency (F0), related to vocal pitch, and the vocal tract length (VTL), related to the height of the speaker. Previous studies on gender categorization in cochlear implant (CI) users found that performance was variable, with few CI users performing at the level of NH listeners. Data collected with recorded speech produced by multiple talkers suggests that CI users might rely more on F0 and less on VTL than NH listeners. However, because VTL cannot be accurately estimated from recordings, it is difficult to know how VTL contributes to gender categorization. In the present study, speech was synthesized to systematically vary F0, VTL, or both. Gender categorization was measured in CI users, as well as in NH participants listening to unprocessed (only synthesized) and vocoded (and synthesized) speech. Perceptual weights for F0 and VTL were derived from the performance data. With unprocessed speech, NH listeners used both cues (normalized perceptual weight: F0 = 3.76, VTL = 5.56). With vocoded speech, NH listeners still made use of both cues but less efficiently (normalized perceptual weight: F0 = 1.68, VTL = 0.63). CI users relied almost exclusively on F0 while VTL perception was profoundly impaired (normalized perceptual weight: F0 = 6.88, VTL = 0.59). As a result, CI users’ gender categorization was abnormal compared to NH listeners. Future CI signal processing should aim to improve the transmission of both F0 cues and VTL cues, as a normal gender categorization may benefit speech understanding in competing talker situations.

The musician effect: does it persist under degraded pitch conditions of cochlear implant simulations?

Cochlear implants (CIs) are auditory prostheses that restore hearing via electrical stimulation of the auditory nerve. Compared to normal acoustic hearing, sounds transmitted through the CI are spectro-temporally degraded, causing difficulties in challenging listening tasks such as speech intelligibility in noise and perception of music. In normal hearing (NH), musicians have been shown to better perform than non-musicians in auditory processing and perception, especially for challenging listening tasks. This “musician effect” was attributed to better processing of pitch cues, as well as better overall auditory cognitive functioning in musicians. Does the musician effect persist when pitch cues are degraded, as it would be in signals transmitted through a CI? To answer this question, NH musicians and non-musicians were tested while listening to unprocessed signals or to signals processed by an acoustic CI simulation. The task increasingly depended on pitch perception: (1) speech intelligibility (words and sentences) in quiet or in noise, (2) vocal emotion identification, and (3) melodic contour identification (MCI). For speech perception, there was no musician effect with the unprocessed stimuli, and a small musician effect only for word identification in one noise condition, in the CI simulation. For emotion identification, there was a small musician effect for both. For MCI, there was a large musician effect for both. Overall, the effect was stronger as the importance of pitch in the listening task increased. This suggests that the musician effect may be more rooted in pitch perception, rather than in a global advantage in cognitive processing (in which musicians would have performed better in all tasks). The results further suggest that musical training before (and possibly after) implantation might offer some advantage in pitch processing that could partially benefit speech perception, and more strongly emotion and music perception.

Music and quality of life in early-deafened late-implanted adult cochlear implant users.

Hypothesis and Background The early-deafened, late-implanted (EDLI) CI users constitute a relatively new and understudied clinical population. To contribute to a better understanding of the implantation outcome, this study evaluated this population for self-reported enjoyment and perception of music. Additionally, correlations of these measures with the self-reported quality of life and everyday hearing ability and a behaviorally measured word recognition test were explored. Materials and Methods EDLI CI users from the Northern Netherlands were sent 4 questionnaires: 1) Dutch Musical Background Questionnaire (enjoyment and perception of music), 2) Nijmegen Cochlear Implant Questionnaire (quality of life), 3) Cochlear Implant Functioning Index (auditory-related functioning), and 4) Speech, Spatial and Qualities of Hearing Scale (hearing ability). Complementary, behavioral word recognition in quiet tests (phoneme score) were completed. Results Twelve (60%) of 20 participants reported music to sound pleasant. In general, the self-perceived quality of music was scored positively. No correlations were observed between enjoyment and perception of music, quality of life, hearing ability, and word recognition. Conclusion The results indicate that, differently than postlingually deafened, EDLI CI users enjoy music and rate the quality of music positively. Potential explanations for the absence of correlations between the music measures and the other outcomes could be that other factors, such as speech perception, contribute more to quality of life of EDLI CI users or that this group simply lacks previous exposure to music with acoustic hearing. Overall, these positive findings may give extra support for implant candidacy of early-deafened individuals, but further studies should be conducted.

Musician effect on perception of spectro-temporally degraded speech, vocal emotion, and music in young adolescents

In adult normal-hearing musicians, perception of music, vocal emotion, and speech in noise has been previously shown to be better than non-musicians, sometimes even with spectro-temporally degraded stimuli. In this study, melodic contour identification, vocal emotion identification, and speech understanding in noise were measured in young adolescent normal-hearing musicians and non-musicians listening to unprocessed or degraded signals. Different from adults, there was no musician effect for vocal emotion identification or speech in noise. Melodic contour identification with degraded signals was significantly better in musicians, suggesting potential benefits from music training for young cochlear-implant users, who experience similar spectro-temporal signal degradations.

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.

Erratum: Musician effect in cochlear implant simulated gender categorization [J. Acoust. Soc. Am. 135, EL159–EL165 (2014)]

(Received 29 March 2014; accepted 7 April 2014)[http://dx.doi.org/10.1121/1.4872299]PACS number(s): 43.71.Bp, 43.75.St, 43.64.Me [ADP]The numbers on page EL163 are incorrect as a result of an author error. The correct version is “Both musicians and non-musicians seemed to utilize both F0 and VTL cues similarly, as confirmed by the cue weighting analysis (musicians: F0 3.74,VTL 6.95; non-musicians: F0 3.72, VTL 5.56)” and “This is shown by the flatter performance lines and by the lower cueweighting (musicians: F0 2.05, VTL 0.35; non-musicians: F0 1.76, VTL 0.64).”