Our sensory systems provide complementary information about the multimodal objects and events that are the target of perception in everyday life. Professional musicians\' specialization in the auditory domain is reflected in the morphology of their brains, which has distinctive characteristics, particularly in areas related to auditory and audio-motor activity. Here, we combined diffusion tensor imaging (DTI) with a behavioral measure of visually induced gain in pitch discrimination, and we used measures of cortical thickness (CT) correlations to assess how auditory specialization and musical expertise are reflected in the structural architecture of white and grey matter relevant to audiovisual processing. Across all participants (n = 45), we found a correlation (p < 0.001) between reliance on visual cues in pitch discrimination and the fractional anisotropy (FA) in the left inferior fronto-occipital fasciculus (IFOF), a structure connecting visual and auditory brain areas. Group analyses also revealed greater cortical thickness correlation between visual and auditory areas in non-musicians (n = 28) compared to musicians (n = 17), possibly reflecting musicians\' auditory specialization (FDR < 10%). Our results corroborate and expand current knowledge of functional specialization with a specific focus on audition, and highlight the fact that perception is essentially multimodal while uni-sensory processing is a specialized task.

Music perception in cochlear implant (CI) users is far from satisfactory, not only because of the technological limitations of current CI devices but also due to the neurophysiological alterations that generally accompany deafness. Early behavioral studies revealed that similar mechanisms underlie musical and lexical pitch perception in CI-based electric hearing. Although neurophysiological studies of the musical pitch perception of English-speaking CI users are actively ongoing, little such research has been conducted with Mandarin-speaking CI users; as Mandarin is a tonal language, these individuals require pitch information to understand speech. The aim of this work was to study the neurophysiological mechanisms accounting for the musical pitch identification abilities of Mandarin-speaking CI users and normal-hearing (NH) listeners. Behavioral and mismatch negativity (MMN) data were analyzed to examine musical pitch processing performance. Moreover, neurophysiological results from CI users with good and bad pitch discrimination performance (according to the just-noticeable differences (JND) and pitch-direction discrimination (PDD) tasks) were compared to identify cortical responses associated with musical pitch perception differences. The MMN experiment was conducted using a passive oddball paradigm, with musical tone C4 (262 Hz) presented as the standard and tones D4 (294 Hz), E4 (330 Hz), G#4 (415 Hz), and C5 (523 Hz) presented as deviants. CI users demonstrated worse musical pitch discrimination ability than did NH listeners, as reflected by larger JND and PDD thresholds for pitch identification, and significantly increased latencies and reduced amplitudes in MMN responses. Good CI performers had better MMN results than did bad performers. Consistent with findings for English-speaking CI users, the results of this work suggest that MMN is a viable marker of cortical pitch perception in Mandarin-speaking CI users.

Introduction: The cochlear implants vary in electrodes in terms of length, width and proximity to the modiolus. The precurved electrode arrays could be placed closer to the modiolus and the ganglion cells compared to straight electrodes. The two types of electrode arrays provide different electrophysiological characteristics; however, proximity to the modiolus may lead to better hearing performance. Aim: To investigate our preliminary electrophysiological results that suggest that the Slim Modiolar (SM) electrode array has the potential to elicit similar neural responses as the thicker perimodiolar (Contour Advance, CA) electrode from the same generation of implants. Method: Subjects that were implanted either with CA or SM electrodes were enrolled, 54 consecutive subjects in each group. All electrodes were introduced into the cochlea via the round window. The diameter of the largest turn of the electrode arrays within the cochlea was measured through postoperative radiography. The energy consumption parameters were estimated 2 months after implantation. Results: The mean of the largest turns of the arrays within the cochlea was 4.2 ± 0.5 mm in the SM group and 4.9 ± 1.1 mm in the CA group. \'Auto power\' was 44.81 ± 5.05% and 50.85 ± 8.35% with SM and CA, respectively. Estimated energy consumption was lower with SM. The differences were statistically significant. Conclusion: Our measurements for a large cohort in each group suggest that the SM electrode array takes a significantly closer position to the modiolus than the CA. This finding supports our earlier electrophysiological result and indicates better performance abilities. Orv Hetil. 2019; 160(31): 1216-1222.
Absztrakt: Bevezetés: A cochlearis implantátumok elektródái gyártótól és modelltől függően különböznek hosszukban, vastagságukban és implantációt követően a csiga tengelyéhez (modiolushoz) viszonyított elhelyezkedésükben. Az előre görbített elektródasorok közelebb kerülnek a stimulálandó ganglion spirale sejtekhez, mint az egyenes elektródasorok, ami a stimulációban tapasztalt elektrofiziológiai különbségek mellett előnyös lehet a hangélmény minőségének szempontjából. Célkitűzés: Előzetes elektrofiziológiai vizsgálataink eredménye szerint ugyanannak a termékcsaládnak (Cochlear™ Nucleus® Profile) a vastagabb (Contour Advance) és vékonyabb (Slim Modiolar) perimodioláris elektródasorai közül a vékonyabbnak az elektródái hasonló töltésmennyiség átadása mellett is képesek hasonló idegi választ kiváltani, mint a vastagabbnak az elektródái. Vizsgálatunkkal arra kerestük a választ, hogy milyen jelenség áll az elektrofiziológiai eredmények hátterében. Módszer: Betegcsoportonként 54, Contour Advance és Slim Modiolar típusú elektródasorral implantáltakat vontunk be. Az elektródasor bevezetése minden esetben a kerek ablakon keresztül történt, a kerek ablak elülső-alsó csontszélének elfúrását követően vagy a nélkül. A műtét másnapján készült, Stenvers-féle röntgenfelvételeken megmértük az elektródasorok által leírt hurok cochleán belüli legnagyobb átmérőjét. A beültetés után két hónappal megbecsültük a kétféle perimodioláris elektródasorral felszerelt implantátum energiafelhasználási mutatóit. Eredmények: A posztoperatív röntgenfelvételeken a vékonyabb perimodioláris elektródasorral implantált csoportban az elektródasorok által leírt hurok cochleán belüli átlagos átmérője 4,2 ± 0,5 mm, míg a vastagabb perimodioláris elektródasorral implantált csoportban 4,9 ± 1,1 mm értéknek adódott. Az ’Auto power’ a CI532-csoportban 44,81 ± 5,05%, a CI512-csoportban 50,85 ± 8,35% volt, tehát alacsonyabb energiafogyasztást tapasztaltunk a CI532-csoportban. Következtetés: Képi diagnosztikai módszerrel, viszonylag nagy esetszám bevonásával arra következtettünk, hogy a vékonyabb perimodioláris elektródasor még a vastagabbnál is szignifikánsan közelebb kerül a modiolushoz, ami elfogadható magyarázatot ad előzetes elektrofiziológiai mérési eredményeinkre. Orv Hetil. 2019; 160(31): 1216–1222.

Cochlear implant (CI) biomechanical constraints result in impoverished spectral cues and poor frequency resolution, making it difficult for users to perceive pitch and timbre. There is emerging evidence that music training may improve CI-mediated music perception; however, much of the existing studies involve time-intensive and less readily accessible in-person music training paradigms, without rigorous experimental control paradigms. Online resources for auditory rehabilitation remain an untapped potential resource for CI users. Furthermore, establishing immediate value from an acute music training program may encourage CI users to adhere to post-implantation rehabilitation exercises. In this study, we evaluated the impact of an acute online music training program on pitch discrimination and timbre identification. Via a randomized controlled crossover study design, 20 CI users and 21 normal hearing (NH) adults were assigned to one of two arms. Arm-A underwent 1 month of online self-paced music training (intervention) followed by 1 month of audiobook listening (control). Arm-B underwent 1 month of audiobook listening followed by 1 month of music training. Pitch and timbre sensitivity scores were taken across three visits: (1) baseline, (2) after 1 month of intervention, and (3) after 1 month of control. We found that performance improved in pitch discrimination among CI users and NH listeners, with both online music training and audiobook listening. Music training, however, provided slightly greater benefit for instrument identification than audiobook listening. For both tasks, this improvement appears to be related to both fast stimulus learning as well as procedural learning. In conclusion, auditory training (with either acute participation in an online music training program or audiobook listening) may improve performance on untrained tasks of pitch discrimination and timbre identification. These findings demonstrate a potential role for music training in perceptual auditory appraisal of complex stimuli. Furthermore, this study highlights the importance and the need for more tightly controlled training studies in order to accurately evaluate the impact of rehabilitation training protocols on auditory processing.

Models of phonological development assume that speech perception precedes speech production and that children acquire suprasegmental features earlier than segmental features. Studies of Chinese-speaking children challenge these assumptions. For example, Chinese-speaking children can produce tones before two-and-a-half years but are not able to discriminate the same tones until after 6 years of age. This study compared the perception and production of monosyllabic Cantonese tones directly in 3 -year-old children. Twenty children and their mothers identified Cantonese tones in a picture identification test and produced monosyllabic tones in a picture labeling task. To control for lexical biases on tone ratings, the mother- and child-productions were low-pass filtered to eliminate lexical information and were presented to five judges for tone classification. Detailed acoustic analysis was performed. Contrary to the view that children master lexical tones earlier than segmental phonemes, results showed that 3-year-old children could not perceive or produce any Cantonese tone with adult-like proficiency and incorrect tone productions were acoustically different from criterion. In contrast to previous findings that Cantonese-speaking children mastered tone production before tone perception, we observed more accuracy during speech perception than production. Findings from Cantonese-speaking children challenge some of the established tenets in theories of phonological development that have been tested mostly with native English speakers.

To assess patient-reported outcomes (PROs) in individuals with significant residual low-frequency hearing and severe-to-profound high-frequency sensorineural hearing loss (SNHL) who received the hybrid cochlear implant (CI).
Prospective, multicenter, nonrandomized, single-arm repeated measures, single-subject design.
Tertiary centers, ambulatory care.
Fifty adults with severe-to-profound high-frequency SNHL and residual low-frequency hearing with aided word recognition scores between 10 and 60% in the ear to be implanted, and in the contralateral ear greater than or equal to implant ear less than or equal to 80%.
Therapeutic; hybrid CI.
Speech, spatial and qualities of hearing scale (SSQ), device use questionnaire (DUQ), University of Washington Clinical Assessment of Music Perception (UW-CAMP) assessed preoperatively and after 6 and 12 (SSQ and DUQ only) months of hybrid CI use.
Significant improvements in mean SSQ ratings were demonstrated at 6 and 12 months postactivation overall and for domains related to speech hearing, spatial hearing, and sound quality. Significant improvement was also found for overall satisfaction on the DUQ and across a number of specific listening situations in addition to aspects related to social engagement. UW-CAMP pitch discrimination and melody and timbre recognition abilities were not compromised postoperatively, allowing hybrid subjects to maintain superior music perception abilities than typically observed with standard CIs.
Patients who received the hybrid CI demonstrated significant PRO benefits on the SSQ and the DUQ after 6 and 12 months of CI use. In addition, given the opportunity to maintain useful low-frequency acoustic hearing, patients retained music listening abilities, as assessed by the UW-CAMP.

One way to understand the relationship between speech perception and production is to examine cases where the two dissociate. This study investigates the hypothesis that perceptual acuity reflected in event-related potentials (ERPs) to rise time of sound amplitude envelope and pitch contour [reflected in the mismatch negativity (MMN)] may associate with individual differences in production among speakers with otherwise comparable perceptual abilities. To test this hypothesis, advantage was taken of an on-going sound change-tone merging in Cantonese, and compared the ERPs between two groups of typically developed native speakers who could discriminate the high rising and low rising tones with equivalent accuracy but differed in the distinctiveness of their production of these tones. Using a passive oddball paradigm, early positive-going EEG components to rise time and MMN to pitch contour were elicited during perception of the two tones. Significant group differences were found in neural responses to rise time rather than pitch contour. More importantly, individual differences in efficiency of tone discrimination in response latency and magnitude of neural responses to rise time were correlated with acoustic measures of F0 offset and rise time differences in productions of the two rising tones.

Temporary threshold shift (TTS) and the discrimination of spectrum patterns after fatiguing noise exposure (170 dB re 1 μPa, 10 min duration) was investigated in a beluga whale, Delphinapterus leucas, using the evoked potential technique. Thresholds were measured using rhythmic (1000/s) pip trains of varying levels and recording the rhythmic evoked responses. Discrimination of spectrum patterns was investigated using rippled-spectrum test stimuli of various levels and ripple densities, recording the rhythmic evoked responses to ripple phase reversals. Before noise exposure, the greatest responses to rippled-spectrum probes were evoked by stimuli with a low ripple density with a decrease in the response magnitude occurring with an increasing ripple density. After noise exposure, both a TTS and a reduction of the responses to rippled-spectrum probes appeared and recovered in parallel. The reduction of the responses to rippled-spectrum probes was maximal for high-magnitude responses at low ripple densities and was negligible for low-magnitude responses at high ripple densities. It is hypothesized that the impacts of fatiguing sounds are not limited by increased thresholds and decreased sensitivity results in reduced ability to discriminate fine spectral content with the greatest impact on the discrimination of spectrum content that may carry the most obvious information about stimulus properties.

The present study investigated pitch processing in Mandarin-speaking children with autism using event-related potential measures. Two experiments were designed to test how acoustic, phonetic and semantic properties of the stimuli contributed to the neural responses for pitch change detection and involuntary attentional orienting. In comparison with age-matched (6-12 years) typically developing controls (16 participants in Experiment 1, 18 in Experiment 2), children with autism (18 participants in Experiment 1, 16 in Experiment 2) showed enhanced neural discriminatory sensitivity in the nonspeech conditions but not for speech stimuli. The results indicate domain specificity of enhanced pitch processing in autism, which may interfere with lexical tone acquisition and language development for children who speak a tonal language.

Membrane potentials and brain plasticity are basic modes of cerebral information processing. Both can be externally (non-invasively) modulated by weak transcranial direct current stimulation (tDCS). Polarity-dependent tDCS-induced reversible circumscribed increases and decreases in cortical excitability and functional changes have been observed following stimulation of motor and visual cortices but relatively little research has been conducted with respect to the auditory cortex. The aim of this pilot study was to examine the effects of tDCS on auditory sensory discrimination in healthy participants (N = 12) assessed with the mismatch negativity (MMN) brain event-related potential (ERP). In a randomized, double-blind, sham-controlled design, participants received anodal tDCS over the primary auditory cortex (2 mA for 20 min) in one session and \'sham\' stimulation (i.e., no stimulation except initial ramp-up for 30 s) in the other session. MMN elicited by changes in auditory pitch was found to be enhanced after receiving anodal tDCS compared to \'sham\' stimulation, with the effects being evidenced in individuals with relatively reduced (vs. increased) baseline amplitudes and with relatively small (vs. large) pitch deviants. Additional studies are needed to further explore relationships between tDCS-related parameters, auditory stimulus features and individual differences prior to assessing the utility of this tool for treating auditory processing deficits in psychiatric and/or neurological disorders.