Fundamental Frequency Discrimination Research Articles

Effect of reducing electrical stimulation rate on hearing performance of Nucleus® cochlear implant recipients

Objective To evaluate whether a 500 pulses per second per channel (pps/ch) rate would provide non-inferior hearing performance compared to the 900 pps/ch rate in the Advanced Combination Encoder (ACE™) sound coding strategy. Design A repeated measures single-subject design was employed, wherein each subject served as their own control. All except one subject used 900 pps/ch at enrolment. After three weeks of using the alternative rate program, both programs were loaded into the sound processor for two more weeks of take-home use. Subjective performance, preference, words in quiet, sentences in babble, music quality, and fundamental frequency (F0) discrimination were assessed using a balanced design. Study sample Data from 18 subjects were analysed, with complete datasets available for 17 subjects. Results Non-inferior performance on all clinical measures was shown for the lower rate program. Subjects’ preference ratings were comparable for the programs, with 53% reporting no difference overall. When a preference was expressed, the 900 pps/ch condition was preferred more often. Conclusion Reducing the stimulation rate from 900 pps/ch to 500 pps/ch did not compromise the hearing outcomes evaluated in this study. A lower pulse rate in future cochlear implants could reduce power consumption, allowing for smaller batteries and processors.

Web-based psychoacoustics: Hearing screening, infrastructure, and validation

Anonymous web-based experiments are increasingly used in many domains of behavioral research. However, online studies of auditory perception, especially of psychoacoustic phenomena pertaining to low-level sensory processing, are challenging because of limited available control of the acoustics, and the inability to perform audiometry to confirm normal-hearing status of participants. Here, we outline our approach to mitigate these challenges and validate our procedures by comparing web-based measurements to lab-based data on a range of classic psychoacoustic tasks. Individual tasks were created using jsPsych, an open-source JavaScript front-end library. Dynamic sequences of psychoacoustic tasks were implemented using Django, an open-source library for web applications, and combined with consent pages, questionnaires, and debriefing pages. Subjects were recruited via Prolific, a subject recruitment platform for web-based studies. Guided by a meta-analysis of lab-based data, we developed and validated a screening procedure to select participants for (putative) normal-hearing status based on their responses in a suprathreshold task and a survey. Headphone use was standardized by supplementing procedures from prior literature with a binaural hearing task. Individuals meeting all criteria were re-invited to complete a range of classic psychoacoustic tasks. For the re-invited participants, absolute thresholds were in excellent agreement with lab-based data for fundamental frequency discrimination, gap detection, and sensitivity to interaural time delay and level difference. Furthermore, word identification scores, consonant confusion patterns, and co-modulation masking release effect also matched lab-based studies. Our results suggest that web-based psychoacoustics is a viable complement to lab-based research. Source code for our infrastructure is provided.

Intelligibility benefit for familiar voices is not accompanied by better discrimination of fundamental frequency or vocal tract length

Speech is more intelligible when it is spoken by familiar than unfamiliar people. If this benefit arises because key voice characteristics like perceptual correlates of fundamental frequency or vocal tract length (VTL) are more accurately represented for familiar voices, listeners may be able to discriminate smaller manipulations to such characteristics for familiar than unfamiliar voices. We measured participants’ (N = 17) thresholds for discriminating pitch (correlate of fundamental frequency, or glottal pulse rate) and formant spacing (correlate of VTL; ‘VTL-timbre’) for voices that were familiar (participants’ friends) and unfamiliar (other participants’ friends). As expected, familiar voices were more intelligible. However, discrimination thresholds were no smaller for the same familiar voices. The size of the intelligibility benefit for a familiar over an unfamiliar voice did not relate to the difference in discrimination thresholds for the same voices. Also, the familiar-voice intelligibility benefit was just as large following perceptible manipulations to pitch and VTL-timbre. These results are more consistent with cognitive accounts of speech perception than traditional accounts that predict better discrimination.

Computer-based musical interval training program for Cochlear implant users and listeners with no known hearing loss.

A musical interval is the difference in pitch between two sounds. The way that musical intervals are used in melodies relative to the tonal center of a key can strongly affect the emotion conveyed by the melody. The present study examines musical interval identification in people with no known hearing loss and in cochlear implant users. Pitch resolution varies widely among cochlear implant users with average resolution an order of magnitude worse than in normal hearing. The present study considers the effect of training on musical interval identification and tests for correlations between low-level psychophysics and higher-level musical abilities. The overarching hypothesis is that cochlear implant users are limited in their ability to identify musical intervals both by low-level access to frequency cues for pitch as well as higher-level mapping of the novel encoding of pitch that implants provide. Participants completed a 2-week, online interval identification training. The benchmark tests considered before and after interval identification training were pure tone detection thresholds, pure tone frequency discrimination, fundamental frequency discrimination, tonal and rhythm comparisons, and interval identification. The results indicate strong correlations between measures of pitch resolution with interval identification; however, only a small effect of training on interval identification was observed for the cochlear implant users. Discussion focuses on improving access to pitch cues for cochlear implant users and on improving auditory training for musical intervals.

Research on the Whole Teaching of Vocal Music Course in University Music Performance Major Based on Multimedia Technology

MT (multimedia technology) music teaching has changed the rigid, unitary, and boring teaching form of traditional music teaching, which has made a comprehensive breakthrough and impact on traditional university music education and has shown a brand-new teaching form to contemporary college students, greatly increasing their strong interest in learning music. In this paper, an objective evaluation method of vocal music quality based on the comparison of sound parameter characteristics is proposed by using the technology of sound signal parameter analysis and extraction. Through confidence measure, reliable data are selected for online adaptive updating of Gaussian mixture model, and the recognition results are smoothed to further remove the instantaneous mutation error. The main melody of singing is discriminated by fundamental frequency discrimination model. Experiments show that the overall accuracy rate of the main melody of vocal music extracted by this algorithm is 86.24%.

Speech in noise perception improved by training fine auditory discrimination: far and applicable transfer of perceptual learning

A longstanding focus of perceptual learning research is learning specificity, the difficulty for learning to transfer to tasks and situations beyond the training setting. Previous studies have focused on promoting transfer across stimuli, such as from one sound frequency to another. Here we examined whether learning could transfer across tasks, particularly from fine discrimination of sound features to speech perception in noise, one of the most frequently encountered perceptual challenges in real life. Separate groups of normal-hearing listeners were trained on auditory interaural level difference (ILD) discrimination, interaural time difference (ITD) discrimination, and fundamental frequency (F0) discrimination with non-speech stimuli delivered through headphones. While ITD training led to no improvement, both ILD and F0 training produced learning as well as transfer to speech-in-noise perception when noise differed from speech in the trained feature. These training benefits did not require similarity of task or stimuli between training and application settings, construing far and wide transfer. Thus, notwithstanding task specificity among basic perceptual skills such as discrimination of different sound features, auditory learning appears readily transferable between these skills and their “upstream” tasks utilizing them, providing an effective approach to improving performance in challenging situations or challenged populations.

Cognitive load distorts the perception of core acoustic dimensions of speech

Dual-tasking negatively impacts on speech perception by raising cognitive load. Previous research has shown that cognitive load increases reliance on lexical knowledge and decreases reliance on phonetic detail. Less is known about the effect of cognitive load on the perception of acoustic dimensions below the phonetic level. This study tested the effect of cognitive load on the ability to discriminate differences in duration, intensity, and fundamental frequency of a synthesized vowel. A psychophysical adaptive procedure was used to obtain just noticeable differences (JNDs) on each dimension under load and no load. Load was imposed via N-back tasks at two levels of difficulty (1-back, 2-back) and under two types of load (images, written nonwords). Compared to a control condition with no cognitive load, all N-back conditions increased JNDs across the three dimensions. JNDs were also higher under 2-back than 1-back load. Nonword load was marginally more detrimental than image load for intensity and fundamental frequency discrimination. Overall, the decreased auditory acuity demonstrates that the effect of cognitive load on the listening experience can be traced to distortions in the perception of core auditory dimensions.Dual-tasking negatively impacts on speech perception by raising cognitive load. Previous research has shown that cognitive load increases reliance on lexical knowledge and decreases reliance on phonetic detail. Less is known about the effect of cognitive load on the perception of acoustic dimensions below the phonetic level. This study tested the effect of cognitive load on the ability to discriminate differences in duration, intensity, and fundamental frequency of a synthesized vowel. A psychophysical adaptive procedure was used to obtain just noticeable differences (JNDs) on each dimension under load and no load. Load was imposed via N-back tasks at two levels of difficulty (1-back, 2-back) and under two types of load (images, written nonwords). Compared to a control condition with no cognitive load, all N-back conditions increased JNDs across the three dimensions. JNDs were also higher under 2-back than 1-back load. Nonword load was marginally more detrimental than image load for intensity and fundamen...

Cognitive load elevates discrimination thresholds of duration, intensity, and f0 for a synthesized vowel.

Dual-tasking negatively impacts on speech perception by raising cognitive load (CL). Previous research has shown that CL increases reliance on lexical knowledge and decreases reliance on phonetic detail. Less is known about the effect of CL on the perception of acoustic dimensions below the phonetic level. This study tested the effect of CL on the ability to discriminate differences in duration, intensity, and fundamental frequency of a synthesized vowel. A psychophysical adaptive procedure was used to obtain just noticeable differences (JNDs) on each dimension under load and no load. Load was imposed by N-back tasks at two levels of difficulty (one-back, two-back) and under two types of load (images, nonwords). Compared to a control condition with no CL, all N-back conditions increased JNDs across the three dimensions. JNDs were also higher under two-back than one-back load. Nonword load was marginally more detrimental than image load for intensity and fundamental frequency discrimination. Overall, the decreased auditory acuity demonstrates that the effect of CL on the listening experience can be traced to distortions in the perception of core auditory dimensions.

Speech perception is similar for musicians and non-musicians across a\xa0wide range of conditions

It remains unclear whether musical training is associated with improved speech understanding in a noisy environment, with different studies reaching differing conclusions. Even in those studies that have reported an advantage for highly trained musicians, it is not known whether the benefits measured in laboratory tests extend to more ecologically valid situations. This study aimed to establish whether musicians are better than non-musicians at understanding speech in a background of competing speakers or speech-shaped noise under more realistic conditions, involving sounds presented in space via a spherical array of 64 loudspeakers, rather than over headphones, with and without simulated room reverberation. The study also included experiments testing fundamental frequency discrimination limens (F0DLs), interaural time differences limens (ITDLs), and attentive tracking. Sixty-four participants (32 non-musicians and 32 musicians) were tested, with the two groups matched in age, sex, and IQ as assessed with Raven’s Advanced Progressive matrices. There was a significant benefit of musicianship for F0DLs, ITDLs, and attentive tracking. However, speech scores were not significantly different between the two groups. The results suggest no musician advantage for understanding speech in background noise or talkers under a variety of conditions.

Bridging the brain structure—brain function gap in prosodic speech processing in older adults

Age-related decline in speech perception may result in difficulties partaking in spoken conversation and potentially lead to social isolation and cognitive decline in older adults. It is therefore important to better understand how age-related differences in neurostructural factors such as cortical thickness (CT) and cortical surface area (CSA) are related to neurophysiological sensitivity to speech cues in younger and older adults. Age-related differences in CT and CSA of bilateral auditory-related areas were extracted using FreeSurfer in younger and older adults with normal peripheral hearing. Behavioral and neurophysiological sensitivity to prosodic speech cues (word stress and fundamental frequency of oscillation) was evaluated using discrimination tasks and a passive oddball paradigm, while EEG was recorded, to quantify mismatch negativity responses. Results revealed (a) higher neural sensitivity (i.e., larger mismatch negativity responses) to word stress in older adults compared to younger adults, suggesting a higher importance of prosodic speech cues in the speech processing of older adults, and (b) lower CT in auditory-related regions in older compared to younger individuals, suggesting neuronal loss associated with aging. Within the older age group, less neuronal loss (i.e., higher CT) in a right auditory-related area (i.e., the supratemporal sulcus) was related to better performance in fundamental frequency discrimination, while higher CSA in left auditory-related areas was associated with higher neural sensitivity toward prosodic speech cues as evident in the mismatch negativity patterns. Overall, our results offer evidence for neurostructural changes in aging that are associated with differences in the extent to which left and right auditory-related areas are involved in speech processing in older adults. We argue that exploring age-related differences in brain structure and function associated with decline in speech perception in older adults may help develop much needed rehabilitation strategies for older adults with central age-related hearing loss.

Fundamental frequency (F0) discrimination of one complex tone in the presence of another: The role of excitation pattern and temporal fine structure cues

The perceptual segregation of simultaneous harmonic complex tones depends partly on differences in the fundamental frequency (F0) between those tones. Human listeners have some ability to group together harmonics of a given F0 and segregate them from harmonics of a different F0. This paper reviews studies of the ability to detect changes in F0 of one complex tone in the presence of another complex tone with the same or a different mean F0. The studies include conditions where the harmonics in the complex tones would have been resolved, partially resolved, or completely unresolved. Modeling using excitation patterns and “summary autocorrelation” and “stabilized auditory image” models suggests that while excitation-pattern cues are useful for complex tones with resolved harmonics, the use of temporal fine structure (phase locking) information is required to account for the small F0DLs obtained when harmonics are barely, if at all, resolved.

Effects of Musical Training and Hearing Loss on Fundamental Frequency Discrimination and Temporal Fine Structure Processing: Psychophysics and Modeling

Several studies have shown that musical training leads to improved fundamental frequency (F0) discrimination for young listeners with normal hearing (NH). It is unclear whether a comparable effect of musical training occurs for listeners whose sensory encoding of F0 is degraded. To address this question, the effect of musical training was investigated for three groups of listeners (young NH, older NH, and older listeners with hearing impairment, HI). In a first experiment, F0 discrimination was investigated using complex tones that differed in harmonic content and phase configuration (sine, positive, or negative Schroeder). Musical training was associated with significantly better F0 discrimination of complex tones containing low-numbered harmonics for all groups of listeners. Part of this effect was caused by the fact that musicians were more robust than non-musicians to harmonic roving. Despite the benefit relative to their non-musicians counterparts, the older musicians, with or without HI, performed worse than the young musicians. In a second experiment, binaural sensitivity to temporal fine structure (TFS) cues was assessed for the same listeners by estimating the highest frequency at which an interaural phase difference was perceived. Performance was better for musicians for all groups of listeners and the use of TFS cues was degraded for the two older groups of listeners. These findings suggest that musical training is associated with an enhancement of both TFS cues encoding and F0 discrimination in young and older listeners with or without HI, although the musicians’ benefit decreased with increasing hearing loss. Additionally, models of the auditory periphery and midbrain were used to examine the effect of HI on F0 encoding. The model predictions reflected the worsening in F0 discrimination with increasing HI and accounted for up to 80 % of the variance in the data.

Fundamental-frequency discrimination based on temporal-envelope cues: Effects of bandwidth and interference.

Both music and speech perception rely on hearing out one pitch in the presence of others. Pitch discrimination of narrowband sounds based only on temporal-envelope cues is rendered nearly impossible by introducing interferers in both normal-hearing listeners and cochlear-implant (CI) users. This study tested whether performance improves in normal-hearing listeners if the target is presented over a broad spectral region. The results indicate that performance is still strongly affected by spectrally remote interferers, despite increases in bandwidth, suggesting that envelope-based pitch is unlikely to allow CI users to perceive pitch when multiple harmonic sounds are presented at once.

Mechanisms underlying speech masking release in hybrid cochlear implant users

Hybrid cochlear implant (CI) users utilize low-frequency acoustic and high-frequency electric stimulation in the implanted ear, outperform traditional CI users in speech perception in noise (Gantz et al., 2017), and show “masking release,” an improvement in speech recognition in fluctuating noise relative to steady noise (Turner et al., 2004). Improved performance in noise has been attributed (but not proven) to the spectral resolution and temporal fine structure (TFS) provided by acoustic hearing. Spondee recognition in two-talker and ten-talker babble was assessed in Hybrid CI users, and masking release was calculated as the percent difference in performance in two-talker (easy condition) and ten-talker (hard condition) babble. Spectral ripple density discrimination thresholds and fundamental frequency discrimination limens was also assessed, as these psychophysical measures reflect underlying spectral resolution and TFS and correlate with speech perception in noise in traditional CI users (Won et al., 2007; Goldsworthy et al., 2013; Goldsworthy, 2015; Jeon et al., 2015). Preliminary data suggest masking release is possible in Hybrid CI users, and that psychophysical measures and masking release may be correlated, suggesting a role of spectral resolution and TFS in masking release. The extent of residual hearing also appears to correlate with psychophysical and masking release performance.

Sustained Cortical and Subcortical Measures of Auditory and Visual Plasticity following Short-Term Perceptual Learning.

Short-term training can lead to improvements in behavioral discrimination of auditory and visual stimuli, as well as enhanced EEG responses to those stimuli. In the auditory domain, fluency with tonal languages and musical training has been associated with long-term cortical and subcortical plasticity, but less is known about the effects of shorter-term training. This study combined electroencephalography (EEG) and behavioral measures to investigate short-term learning and neural plasticity in both auditory and visual domains. Forty adult participants were divided into four groups. Three groups trained on one of three tasks, involving discrimination of auditory fundamental frequency (F0), auditory amplitude modulation rate (AM), or visual orientation (VIS). The fourth (control) group received no training. Pre- and post-training tests, as well as retention tests 30 days after training, involved behavioral discrimination thresholds, steady-state visually evoked potentials (SSVEP) to the flicker frequencies of visual stimuli, and auditory envelope-following responses simultaneously evoked and measured in response to rapid stimulus F0 (EFR), thought to reflect subcortical generators, and slow amplitude modulation (ASSR), thought to reflect cortical generators. Enhancement of the ASSR was observed in both auditory-trained groups, not specific to the AM-trained group, whereas enhancement of the SSVEP was found only in the visually-trained group. No evidence was found for changes in the EFR. The results suggest that some aspects of neural plasticity can develop rapidly and may generalize across tasks but not across modalities. Behaviorally, the pattern of learning was complex, with significant cross-task and cross-modal learning effects.

Aging effect on categorical perception of Mandarin level-rising and level-falling tones

The primary purpose of the study was to investigate the aging effect on categorical perception of Mandarin Chinese tone 1 (level F0 pitch contour) and tone 2 (rising F0 pitch contour), as well as tone 1 and tone 4 (falling F0 pitch contour). Using level/rising and level/falling fundamental frequency continuum, both tone identification and discrimination was measured for older and younger native Mandarin listeners. Moreover, the stimuli duration was manipulated at 100, 200, and 400 ms with a purpose to examine whether longer duration made tone perception easier for the older listeners. Results reported reduced catgoricality in terms of shallower identification slope and smaller discrimination peakedness for the older listeners compared with their younger counterparts. Meanwhile, longer duration was observed with enhanced categorical perception of lexical tones for the older listeners. These results were interpreted as the decline of aging-related temporal/spectral processing and inhibitory control in the central auditory system.

Correlations Between Pitch and Phoneme Perception in Cochlear Implant Users and Their Normal Hearing Peers.

This study examined correlations between pitch and phoneme perception for nine cochlear implant users and nine normal hearing listeners. Pure tone frequency discrimination thresholds were measured for frequencies of 500, 1000, and 2000 Hz. Complex tone fundamental frequency (F0) discrimination thresholds were measured for F0s of 110, 220, and 440 Hz. The effects of amplitude and frequency roving were measured under the rationale that individuals who are robust to such perturbations would perform better on phoneme perception measures. Phoneme identification was measured using consonant and vowel materials in quiet, in stationary speech-shaped noise (SSN), in spectrally notched SSN, and in temporally gated SSN. Cochlear implant pure tone frequency discrimination thresholds ranged between 1.5 and 9.9 %, while cochlear implant complex tone F0 discrimination thresholds ranged between 2.6 and 28.5 %. On average, cochlear implant users had 5.3 dB of masking release for consonants and 8.4 dB of masking release for vowels when measured in temporally gated SSN compared to stationary SSN. Correlations with phoneme identification measures were generally higher for complex tone discrimination measures than for pure tone discrimination measures. Correlations with phoneme identification measures were also generally higher for pitch perception measures that included amplitude and frequency roving. The strongest correlations were observed for measures of complex tone F0 discrimination with phoneme identification in temporally gated SSN. The results of this study suggest that musical training or signal processing strategies that improve F0 discrimination should improve consonant identification in fluctuating noise.

Fundamental-frequency discrimination using noise-band-vocoded harmonic complexes in older listeners with normal hearing.

Voice-pitch cues provide detailed information about a talker that help a listener to understand speech in complex environments. Temporal-envelope based voice-pitch coding is important for listeners with hearing impairment, especially listeners with cochlear implants, as spectral resolution is not sufficient to provide a spectrally based voice-pitch cue. The effect of aging on the ability to glean voice-pitch information using temporal envelope cues is not completely understood. The current study measured fundamental frequency (f0) discrimination limens in normal-hearing younger and older adults while listening to noise-band vocoded harmonic complexes with varying numbers of spectral channels. Age-related disparities in performance were apparent across all conditions, independent of spectral degradation and/or fundamental frequency. The findings have important implications for older listeners with normal hearing and hearing loss, who may be inherently limited in their ability to perceive f0 cues due to senescent decline in auditory function.

Deficits in the pitch sensitivity of cochlear-implanted children speaking English or Mandarin.

Sensitivity to complex pitch is notoriously poor in adults with cochlear implants (CIs), but it is unclear whether this is true for children with CIs. Many are implanted today at a very young age, and factors related to brain plasticity (age at implantation, duration of CI experience, and speaking a tonal language) might have strong influences on pitch sensitivity. School-aged children participated, speaking English or Mandarin, having normal hearing (NH) or wearing a CI, using their clinically assigned settings with envelope-based coding strategies. Percent correct was measured in three-interval three-alternative forced choice tasks, for the discrimination of fundamental frequency (F0) of broadband harmonic complexes, and for the discrimination of sinusoidal amplitude modulation rate (AMR) of broadband noise, with reference frequencies at 100 and 200 Hz to focus on voice pitch processing. Data were fitted using a maximum-likelihood technique. CI children displayed higher thresholds and shallower slopes than NH children in F0 discrimination, regardless of linguistic background. Thresholds and slopes were more similar between NH and CI children in AMR discrimination. Once the effect of chronological age was extracted from the variance, the aforementioned factors related to brain plasticity did not contribute significantly to the CI children's sensitivity to pitch. Unless different strategies attempt to encode fine structure information, potential benefits of plasticity may be missed.

Symmetric interactions and interference between pitch and timbre

Variations in the spectral shape of harmonic tone complexes are perceived as timbre changes and can lead to poorer fundamental frequency (F0) or pitch discrimination. Less is known about the effects of F0 variations on spectral shape discrimination. The aims of the study were to determine whether the interactions between pitch and timbre are symmetric, and to test whether musical training affects listeners' ability to ignore variations in irrelevant perceptual dimensions. Difference limens (DLs) for F0 were measured with and without random, concurrent, variations in spectral centroid, and vice versa. Additionally, sensitivity was measured as the target parameter and the interfering parameter varied by the same amount, in terms of individual DLs. Results showed significant and similar interference between pitch (F0) and timbre (spectral centroid) dimensions, with upward spectral motion often confused for upward F0 motion, and vice versa. Musicians had better F0DLs than non-musicians on average, but similar spectral centroid DLs. Both groups showed similar interference effects, in terms of decreased sensitivity, in both dimensions. Results reveal symmetry in the interference effects between pitch and timbre, once differences in sensitivity between dimensions and subjects are controlled. Musical training does not reliably help to overcome these effects.