Non-speech Conditions Research Articles

Neurophysiological correlates of the perceptual magnet effect in speech perception

This study investigated the Perceptual Magnet Effect (PME) in speech perception using behavioral and Event-Related Potentials (ERP) measures. There were two primary research questions: (1) whether category goodness rating influences speech discrimination with reduced sensitivity near the prototype and increased sensitivity in the vicinity of a poor exemplar, (2) whether the PME is domain-specific to speech sounds. Twenty adult native English speakers participated in identification, goodness rating, and discrimination tasks. The stimuli were synthesized vowels for /a/ and their nonspeech analogs by systematically varying the first two formants. ERP oddball conditions included four conditions presented in a counter-balanced order with the prototypical /a/ as the standard stimuli and its variants as deviants, and a non-prototypical /a/ as the standard and its variants as deviants, as well as the nonspeech matches. Results indicated that participants rated vowel category goodness based on the F2/F1 ratio for the /a/ sounds. Mismatch negativity amplitudes in the two speech conditions aligned with PME predictions, but similar patterns were also observed in the nonspeech conditions. The findings collectively demonstrated neurophysiological evidence for the perceptual organization of within-category variations in line with PME, which may transfer to auditory processing of similar acoustic patterns in nonspeech.

Effects of Amateur Musical Experience on Categorical Perception of Lexical Tones by Native Chinese Adults: An ERP Study.

Music impacting on speech processing is vividly evidenced in most reports involving professional musicians, while the question of whether the facilitative effects of music are limited to experts or may extend to amateurs remains to be resolved. Previous research has suggested that analogous to language experience, musicianship also modulates lexical tone perception but the influence of amateur musical experience in adulthood is poorly understood. Furthermore, little is known about how acoustic information and phonological information of lexical tones are processed by amateur musicians. This study aimed to provide neural evidence of cortical plasticity by examining categorical perception of lexical tones in Chinese adults with amateur musical experience relative to the non-musician counterparts. Fifteen adult Chinese amateur musicians and an equal number of non-musicians participated in an event-related potential (ERP) experiment. Their mismatch negativities (MMNs) to lexical tones from Mandarin Tone 2–Tone 4 continuum and non-speech tone analogs were measured. It was hypothesized that amateur musicians would exhibit different MMNs to their non-musician counterparts in processing two aspects of information in lexical tones. Results showed that the MMN mean amplitude evoked by within-category deviants was significantly larger for amateur musicians than non-musicians regardless of speech or non-speech condition. This implies the strengthened processing of acoustic information by adult amateur musicians without the need of focused attention, as the detection of subtle acoustic nuances of pitch was measurably improved. In addition, the MMN peak latency elicited by across-category deviants was significantly shorter than that by within-category deviants for both groups, indicative of the earlier processing of phonological information than acoustic information of lexical tones at the pre-attentive stage. The results mentioned above suggest that cortical plasticity can still be induced in adulthood, hence non-musicians should be defined more strictly than before. Besides, the current study enlarges the population demonstrating the beneficial effects of musical experience on perceptual and cognitive functions, namely, the effects of enhanced speech processing from music are not confined to a small group of experts but extend to a large population of amateurs.

Late negative response revealed language-specific processing of word-level prosodic phonology in the adult brain

Native speakers develop specialized neural architectures in the processing of auditory patterns found in their language. However, little is known about the neural basis of language-specific processing of phonological patterns beyond the syllable level. The current event-related potential (ERP) study investigated cortical processing of native vs. nonnative prosodic phonology in a disyllabic context. The participants were 18 normal native Chinese-speaking adults who had at least six years of English-as-a-second-language course work in school. The speech stimuli included disyllabic nonsense words spoken in Chinese and in English, which were matched in syllabic structure and digitally edited for matching in overall duration and intensity. The control nonspeech stimuli were hummed versions of the speech stimuli, which preserved the acoustic prosodic features but not the phonetic content. The ERP data were obtained with a passive listening paradigm, showing an enhanced late negative response (LNR) for the native vs. nonnative comparison in the speech condition but not in the nonspeech condition. These results provided the initial evidence that the LNR component can reflect language-specific differences in prosodic phonology beyond auditory processing of the critical acoustic cues at the supra-syllabic level.Native speakers develop specialized neural architectures in the processing of auditory patterns found in their language. However, little is known about the neural basis of language-specific processing of phonological patterns beyond the syllable level. The current event-related potential (ERP) study investigated cortical processing of native vs. nonnative prosodic phonology in a disyllabic context. The participants were 18 normal native Chinese-speaking adults who had at least six years of English-as-a-second-language course work in school. The speech stimuli included disyllabic nonsense words spoken in Chinese and in English, which were matched in syllabic structure and digitally edited for matching in overall duration and intensity. The control nonspeech stimuli were hummed versions of the speech stimuli, which preserved the acoustic prosodic features but not the phonetic content. The ERP data were obtained with a passive listening paradigm, showing an enhanced late negative response (LNR) for the nativ...

Auditory and audio–visual processing in patients with cochlear, auditory brainstem, and auditory midbrain implants: An EEG study

There is substantial variability in speech recognition ability across patients with cochlear implants (CIs), auditory brainstem implants (ABIs), and auditory midbrain implants (AMIs). To better understand how this variability is related to central processing differences, the current electroencephalography (EEG) study compared hearing abilities and auditory-cortex activation in patients with electrical stimulation at different sites of the auditory pathway. Three different groups of patients with auditory implants (Hannover Medical School; ABI: n = 6, CI: n = 6; AMI: n = 2) performed a speeded response task and a speech recognition test with auditory, visual, and audio-visual stimuli. Behavioral performance and cortical processing of auditory and audio-visual stimuli were compared between groups. ABI and AMI patients showed prolonged response times on auditory and audio-visual stimuli compared with NH listeners and CI patients. This was confirmed by prolonged N1 latencies and reduced N1 amplitudes in ABI and AMI patients. However, patients with central auditory implants showed a remarkable gain in performance when visual and auditory input was combined, in both speech and non-speech conditions, which was reflected by a strong visual modulation of auditory-cortex activation in these individuals. In sum, the results suggest that the behavioral improvement for audio-visual conditions in central auditory implant patients is based on enhanced audio-visual interactions in the auditory cortex. Their findings may provide important implications for the optimization of electrical stimulation and rehabilitation strategies in patients with central auditory prostheses. Hum Brain Mapp 38:2206-2225, 2017. © 2017 Wiley Periodicals, Inc.

On the early neural perceptual integrality of tones and vowels

Abstract The current study adopted the MMN additivity approach to examine the pre-attentive perceptual integration of vowels and tones. Twenty Cantonese listeners participated in the ERP experiment. Using the passive oddball paradigm, we elicited tone-MMN, vowel-MMN and double-MMN in the speech condition; and fundamental frequency-MMN, formant frequency-MMN and double-MMN in the non-speech condition. In both conditions, the double-MMNs were significantly smaller in amplitude than the sum of single feature MMNs. Morphological comparisons showed no significant difference in the latency and topographic patterns between vowel-MMN and tone-MMN, and marginal significant differences between formant frequency-MMN and fundamental frequency-MMN. Collectively, results reflect the perceptual integration of tones and vowels at the phonological level, and partial integration of fundamental frequency and formant frequency at the auditory level.

Pitch perception and production in congenital amusia: Evidence from Cantonese speakers.

This study investigated pitch perception and production in speech and music in individuals with congenital amusia (a disorder of musical pitch processing) who are native speakers of Cantonese, a tone language with a highly complex tonal system. Sixteen Cantonese-speaking congenital amusics and 16 controls performed a set of lexical tone perception, production, singing, and psychophysical pitch threshold tasks. Their tone production accuracy and singing proficiency were subsequently judged by independent listeners, and subjected to acoustic analyses. Relative to controls, amusics showed impaired discrimination of lexical tones in both speech and non-speech conditions. They also received lower ratings for singing proficiency, producing larger pitch interval deviations and making more pitch interval errors compared to controls. Demonstrating higher pitch direction identification thresholds than controls for both speech syllables and piano tones, amusics nevertheless produced native lexical tones with comparable pitch trajectories and intelligibility as controls. Significant correlations were found between pitch threshold and lexical tone perception, music perception and production, but not between lexical tone perception and production for amusics. These findings provide further evidence that congenital amusia is a domain-general language-independent pitch-processing deficit that is associated with severely impaired music perception and production, mildly impaired speech perception, and largely intact speech production.

Auditory Perceptual Learning in Adults with and without Age-Related Hearing Loss.

Introduction : Speech recognition in adverse listening conditions becomes more difficult as we age, particularly for individuals with age-related hearing loss (ARHL). Whether these difficulties can be eased with training remains debated, because it is not clear whether the outcomes are sufficiently general to be of use outside of the training context. The aim of the current study was to compare training-induced learning and generalization between normal-hearing older adults and those with ARHL.Methods : Fifty-six listeners (60–72 y/o), 35 participants with ARHL, and 21 normal hearing adults participated in the study. The study design was a cross over design with three groups (immediate-training, delayed-training, and no-training group). Trained participants received 13 sessions of home-based auditory training over the course of 4 weeks. Three adverse listening conditions were targeted: (1) Speech-in-noise, (2) time compressed speech, and (3) competing speakers, and the outcomes of training were compared between normal and ARHL groups. Pre- and post-test sessions were completed by all participants. Outcome measures included tests on all of the trained conditions as well as on a series of untrained conditions designed to assess the transfer of learning to other speech and non-speech conditions.Results : Significant improvements on all trained conditions were observed in both ARHL and normal-hearing groups over the course of training. Normal hearing participants learned more than participants with ARHL in the speech-in-noise condition, but showed similar patterns of learning in the other conditions. Greater pre- to post-test changes were observed in trained than in untrained listeners on all trained conditions. In addition, the ability of trained listeners from the ARHL group to discriminate minimally different pseudowords in noise also improved with training.Conclusions : ARHL did not preclude auditory perceptual learning but there was little generalization to untrained conditions. We suggest that most training-related changes occurred at higher level task-specific cognitive processes in both groups. However, these were enhanced by high quality perceptual representations in the normal-hearing group. In contrast, some training-related changes have also occurred at the level of phonemic representations in the ARHL group, consistent with an interaction between bottom-up and top-down processes.

Pitch Processing in Tonal-Language-Speaking Children with Autism: An Event-Related Potential Study.

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.

Multiple levels of linguistic and paralinguistic features contribute to voice recognition.

Voice or speaker recognition is critical in a wide variety of social contexts. In this study, we investigated the contributions of acoustic, phonological, lexical, and semantic information toward voice recognition. Native English speaking participants were trained to recognize five speakers in five conditions: non-speech, Mandarin, German, pseudo-English, and English. We showed that voice recognition significantly improved as more information became available, from purely acoustic features in non-speech to additional phonological information varying in familiarity. Moreover, we found that the recognition performance is transferable between training and testing in phonologically familiar conditions (German, pseudo-English, and English), but not in unfamiliar (Mandarin) or non-speech conditions. These results provide evidence suggesting that bottom-up acoustic analysis and top-down influence from phonological processing collaboratively govern voice recognition.

Evidence for a general auditory processing deficit in developmental dyslexia from a discrimination paradigm using speech versus nonspeech sounds matched in complexity.

It is unknown whether phonological deficits are the primary cause of developmental dyslexia or whether they represent a secondary symptom resulting from impairments in processing basic acoustic parameters of speech. This might be due, in part, to methodological difficulties. Our aim was to overcome two of these difficulties: the comparability of stimulus material and task in speech versus nonspeech conditions. In this study, the authors (a) assessed auditory processing of German vowel center stimuli, spectrally rotated versions of these stimuli, and bands of formants; (b) used the same task for linguistic and nonlinguistic conditions; and (c) varied systematically temporal and spectral parameters inherent in the German vowel system. Forty-two adolescents and adults with and without reading disabilities participated. Group differences were found for all linguistic and nonlinguistic conditions for both temporal and spectral parameters. Auditory deficits were identified in most but not all participants with dyslexia. These deficits were not restricted to speech stimuli-they were also found for nonspeech stimuli with equal and lower complexity compared with the vowel stimuli. Temporal deficits were not observed in isolation. These results support the existence of a general auditory processing impairment in developmental dyslexia.

Neural Dynamics of Audiovisual Integration for Speech and Non-Speech Stimuli: A Psychophysical Study

This study investigated the extent to which audiovisual speech integration is special by comparing behavioral and neural measures using both speech and non-speech stimuli. An audiovisual recognition experiment presenting listen- ers with auditory, visual, and audiovisual stimuli was implemented. The auditory component consisted of sine wave speech, and the visual component consisted of point light displays, which include point-light dots that highlight a talker's points of articulation. In the first phase, listeners engaged in a discrimination task where they were unaware of the linguis- tic nature of the auditory and visual stimuli. In the second phase, they were informed that the auditory and visual stimuli were spoken utterances of /be/ (bay) and /de/ (day), and they engaged in the same task. The neural dynamics of audiovisual integration was investigated by utilizing EEG, including mean Global Field Power and current density recon- struction (CDR). As predicted, support for divergent regions of multisensory integration between the speech and non- speech stimuli was obtained, namely greater posterior parietal activation in the non-speech condition. Conversely, reac- tion-time measures indicated qualitatively similar multisensory integration across experimental conditions.

Rhythmic Grouping Biases Constrain Infant Statistical Learning

Linguistic stress and sequential statistical cues to word boundaries interact during speech segmentation in infancy. However, little is known about how the different acoustic components of stress constrain statistical learning. The current studies were designed to investigate whether intensity and duration each function independently as cues to initial prominence (trochaic-based hypothesis) or whether, as predicted by the Iambic-Trochaic Law (ITL), intensity and duration have characteristic and separable effects on rhythmic grouping (ITL-based hypothesis) in a statistical learning task. Infants were familiarized with an artificial language (Experiments 1 & 3) or a tone stream (Experiment 2) in which there was an alternation in either intensity or duration. In addition to potential acoustic cues, the familiarization sequences also contained statistical cues to word boundaries. In speech (Experiment 1) and non-speech (Experiment 2) conditions, 9-month-old infants demonstrated discrimination patterns consistent with an ITL-based hypothesis: intensity signaled initial prominence and duration signaled final prominence. The results of Experiment 3, in which 6.5-month-old infants were familiarized with the speech streams from Experiment 1, suggest that there is a developmental change in infants' willingness to treat increased duration as a cue to word offsets in fluent speech. Infants' perceptual systems interact with linguistic experience to constrain how infants learn from their auditory environment.

Adapted Assessment of Phonological Sensitivity Skills

Children with little or no functional speech are at risk for literacy acquisition. Assessment of early literacy skills is particularly challenging among this population due to the need for children to provide a spoken response to tasks. This study explored the effects of adapted response modes on measures of phonological sensitivity. Assessment tasks were administered in three response conditions to 12 typically developing kindergarten students with 4 participants in each response condition. Identical tasks were administered in the speech response condition, speech response condition combined with picture response arrays, and nonspeech response condition whereby participants pointed to answers on picture response arrays. Results revealed no statistically significant differences in scores across the three response conditions for 11 of 12 tasks, suggesting that nonspeech assessment of phonological sensitivity should continue to be explored as a feasible option for use among individuals with little or no functional speech.

Optical Brain Imaging Reveals General Auditory and Language-Specific Processing in Early Infant Development

This study uses near-infrared spectroscopy in young infants in order to elucidate the nature of functional cerebral processing for speech. Previous imaging studies of infants' speech perception revealed left-lateralized responses to native language. However, it is unclear if these activations were due to language per se rather than to some low-level acoustic correlate of spoken language. Here we compare native (L1) and non-native (L2) languages with 3 different nonspeech conditions including emotional voices, monkey calls, and phase scrambled sounds that provide more stringent controls. Hemodynamic responses to these stimuli were measured in the temporal areas of Japanese 4 month-olds. The results show clear left-lateralized responses to speech, prominently to L1, as opposed to various activation patterns in the nonspeech conditions. Furthermore, implementing a new analysis method designed for infants, we discovered a slower hemodynamic time course in awake infants. Our results are largely explained by signal-driven auditory processing. However, stronger activations to L1 than to L2 indicate a language-specific neural factor that modulates these responses. This study is the first to discover a significantly higher sensitivity to L1 in 4 month-olds and reveals a neural precursor of the functional specialization for the higher cognitive network.

Change and novelty detection in speech and non-speech sound streams

The aim of the present study was to determine differences in cortical processing of consonant–vowel syllables and acoustically matched non-speech sounds, as well as novel human and nonhuman sounds. Event-related potentials (ERPs) were recorded to vowel, vowel duration, consonant, syllable intensity, and frequency changes as well as corresponding changes in their non-speech counterparts with the multi-feature mismatch negativity (MMN) paradigm. Enhanced responses to linguistically relevant deviants were expected. Indeed, the vowel and frequency deviants elicited significantly larger MMNs in the speech than non-speech condition. Minimum-norm source localization algorithm was applied to determine hemispheric asymmetry in the responses. Language relevant deviants (vowel, duration and – to a lesser degree – frequency) showed higher activation in the left than right hemisphere to stimuli in the speech condition. Novel sounds elicited novelty P3 waves, the amplitude of which for nonhuman sounds was larger in the speech than non-speech condition. The current MMN results imply enhanced processing of linguistically relevant information at the pre-attentive stage and in this way support the domain-specific model of speech perception.

An external neck brace to support the peristomal fixation of an automatic stoma valve (ASV): 3D stereophotogrammetrical assessment

Conclusion: The external neck brace (ENB) is a new concept in the improvement of peristomal fixation of an automatic stoma valve (ASV), which was evaluated with a new imaging method. The addition of the ENB to the Flexiderm (FLD) and Xtrabase (XB) adhesives significantly reduced absolute mean differences between the speech and the non-speech conditions. Objectives: After total laryngectomy, peristomal fixation problems of adhesives and stoma valves are still the main reasons for the relatively small number of patients that actually use an ASV on a daily basis. Several concepts could not prevent these fixation problems. To overcome or at least diminish these attachment problems, an ENB has been developed to support peristomal adhesives. The mechanism behind this brace is that it absorbs the high stomal pressures created during tracheoesophageal speech. In this pilot study the mechanism outlined above was objectified using 3D stereophotogrammetrical measurements. Methods: This was a prospective clinical pilot study in a university hospital setting, involving nine laryngectomized patients. Ten 3D images were taken of all patients using stereophotogrammetry; five pictures during a moment of speech and five during a non-speech condition. Two different peristomal adhesives were used during these two conditions: the Provox® Flexiderm™ (FLD) adhesive and the Provox® Xtrabase® (XB) adhesive, both with and without the addition of the ENB. Besides these four combinations, a final fifth set-up using all the components (FLD + XB-ring + ENB) was added. Absolute mean differences were compared between two photographs of the area of interest, which is covered by the adhesive for all five different set-ups mentioned above. This was done during speech and non-speech conditions. Results: Absolute mean differences at the region of the base plate between speech and non-speech conditions were most obvious while using just the FLD adhesive (4.70 mm). The use of the ENB significantly reduced the absolute mean difference to 0.58 mm (p < 0.02). The suggested set-up with a basis of the FLD adhesive combined with the solid ring extracted from the XB adhesive and the ENB showed the smallest absolute mean difference of 0.38 mm between speech and non-speech conditions (p < 0.025).

Mu wave suppression during the perception of meaningless syllables: EEG evidence of motor recruitment

Motor involvement in speech perception has been recently studied using a variety of techniques. In the current study, EEG measurements from Cz, C3 and C4 electrodes were used to examine the relative power of the mu rhythm (i.e., 8-13 Hz) in response to various audio-visual speech and non-speech stimuli, as suppression of these rhythms is considered an index of 'mirror neuron' (i.e., motor) activity. Fourteen adult native English speaking females watched and listened to nine audio-video stimuli clips assembled from three different auditory stimuli (speech, noise, and pure tone) combined with three different video stimuli (speech, noise, and kaleidoscope-made from scrambling an image from the visual speech). Relative to the noise-noise (baseline condition), all visual speech conditions resulted in significant levels of suppression, a finding that is consistent with previous reports of mirror activity to visual speech and mu suppression to 'biological' stimuli. None of the non-speech conditions or conditions in which speech was presented via audition only resulted in any significant suppression of the mu rhythm in this population. Thus, visual speech perception appears to be more closely associated with motor activity than acoustic speech perception. It is postulated that in this study, the processing demands incurred by the task were insufficient for inducing significant mu suppression via acoustic speech only. The findings are discussed in theoretical contexts of speech perception and the mirror system. We suggest that this technique may offer a cost-efficient, non-invasive technique for measuring motor activity during speech perception.

Impedance Control and Its Relation to Precision in Orofacial Movement

Speech production involves some of the most precise and finely timed patterns of human movement. Here, in the context of jaw movement in speech, we show that spatial precision in speech production is systematically associated with the regulation of impedance and in particular, with jaw stiffness--a measure of resistance to displacement. We estimated stiffness and also variability during movement using a robotic device to apply brief force pulses to the jaw. Estimates of stiffness were obtained using the perturbed position and force trajectory and an estimate of what the trajectory would be in the absence of load. We estimated this "reference trajectory" using a new technique based on Fourier analysis. A moving-average (MA) procedure was used to estimate stiffness by modeling restoring force as the moving average of previous jaw displacements. The stiffness matrix was obtained from the steady state of the MA model. We applied this technique to data from 31 subjects whose jaw movements were perturbed during speech utterances and kinematically matched nonspeech movements. We observed systematic differences in stiffness over the course of jaw-lowering and jaw-raising movements that were correlated with measures of kinematic variability. Jaw stiffness was high and variability was low early and late in the movement when the jaw was elevated. Stiffness was low and variability was high in the middle of movement when the jaw was lowered. Similar patterns were observed for speech and nonspeech conditions. The systematic relationship between stiffness and variability points to the idea that stiffness regulation is integral to the control of orofacial movement variability.

Early cortical processing of linguistic pitch patterns as revealed by the mismatch negativity

Previous brain imaging studies have shown the left hemispheric dominance for processing of lexical tone in native speakers. However, the low temporal resolution related to neuroimaging techniques might not explicitly detect the brain activities that occur at a relatively small or a determined time frame. We used the mismatch negativity (MMN) and a source estimation technique (low-resolution electromagnetic tomography [LORETA]) to probe the brain activities underlying the early pre-attentive processing of Mandarin lexical tone and intonation. A passive oddball paradigm was applied to present tone and intonation contrast in a speech and nonspeech context. The results showed that no difference of the MMN amplitudes existed between speech and nonspeech conditions, although a larger MMN was found for tone than intonation condition. Source localization of the MMNs for all of the conditions showed the right hemispheric dominance, regardless of their linguistic functions (tone vs. intonation) or speech context (speech vs. nonspeech). Interestingly, the MMN generator for normal tone and hummed tone originated from the same cortical area (right parietal lobe, BA 19). These findings suggest that the pre-attentive cortical processing can be modulated not only by speech stimuli, but also by their nonspeech hums. Our data are compatible with the acoustic hypothesis of speech processing.

Contribution of the anterior insula to temporal auditory processing deficits in developmental dyslexia

Developmental dyslexia has been assumed to arise from general auditory deficits, compromising rapid temporal integration both of linguistic and nonlinguistic acoustic stimuli. Because the effort of auditory temporal processing of speech and nonspeech test materials may depend on presentation rate, fMRI measurements were performed in dyslexics and controls during passive listening to series of syllable and click sounds, using a parametric approach. Controls showed a decrease of hemodynamic brain activation within the right and an increase within the left anterior insula as a function of the presentation rate both of click as well as syllable trains. By contrast, dyslexics exhibited this profile of hemodynamic responses under the nonspeech condition only. As concerns syllables, activation in dyslexics did not depend on presentation rate. Moreover, a subtraction analysis of hemodynamic main effects across conditions and groups revealed decreased activation both of the left and right anterior insula in dyslexics compared to controls during application both of click and syllables. These results indicate, in line with preceding studies, that the insula of both hemispheres is involved in auditory temporal processing of nonlinguistic auditory stimuli and demonstrate, furthermore, that these operations of intrasylvian cortex also extend to the linguistic domain. In addition, our data suggest that the anterior insula represents an important neural correlate of deficient temporal processing of speech and nonspeech sounds in dyslexia.