Listening to a Dysphonic Speaker in Noise May Impede Children's Spoken Language Processing in a Realistic Classroom Setting.

Purpose The aim of this study was to investigate children's processing of dysphonic speech in a realistic classroom setting, under the influence of added classroom noise. Method Typically developing 6-year-old primary school children performed two listening tasks in their regular classrooms: a phoneme discrimination task to assess speech perception and a sentence-picture matching task to assess listening comprehension. Speech stimuli were played back in either a typical or an impaired voice quality. Children performed the tasks in the presence of induced classroom noise at signal-to-noise ratios between +2 and +9 dB. Results Children's performance in the phoneme discrimination task decreased significantly when the speaker's voice was impaired. The effect of voice quality on sentence-picture matching depended on task demands: Easy sentences were processed more accurately in the impaired-voice condition than in the typical-voice condition. Signal-to-noise ratio effects are discussed in light of methodological constraints. Conclusions Listening to a dysphonic teacher in a noisy classroom may impede children's perception of speech, particularly when phonological discrimination is needed to disambiguate the speech input. Future research regarding the interaction of voice quality and task demands is necessary.

Noise and a Speaker's Impaired Voice Quality Disrupt Spoken Language Processing in School-Aged Children: Evidence From Performance and Response Time Measures.

Purpose Our aim was to investigate isolated and combined effects of speech-shaped noise (SSN) and a speaker's impaired voice quality on spoken language processing in first-grade children. Method In individual examinations, 53 typically developing children aged 5-6 years performed a speech perception task (phoneme discrimination) and a listening comprehension task (sentence-picture matching). Speech stimuli were randomly presented in a 2 × 2 factorial design with the factors noise (no added noise vs. SSN at 0- dB SNR) and voice quality (normal voice vs. impaired voice). Outcome measures were task performance and response time (RT). Results SSN and impaired voice quality significantly lowered children's performance and increased RTs in the speech perception task, particularly when combined. Regarding listening comprehension, a significant interaction between noise and voice quality indicated that children's performance was hindered by SSN when the speaker's voice was impaired but not when it was normal. RTs in this task were unaffected by noise or voice quality. Conclusions Results suggest that speech signal degradations caused by a speaker's impaired voice and background noise generate more processing errors and increased listening effort in young school-aged children. This finding is vital for classroom listening and highlights the importance of ensuring teachers' vocal health and adequate room acoustics.

Assisted and unassisted recession of functional anomalies associated with dysprosody in adults who stutter.

PURPOSE: Speech in persons who stutter (PWS) is associated with disturbed prosody (speech melody and intonation), which may impact communication. The neural correlates of PWS' altered prosody during speaking are not known, neither is how a speech-restructuring therapy affects prosody at both a behavioral and a cerebral level. METHODS: In this fMRI study, we explored group differences in brain activation associated with the production of different kinds of prosody in 13 male adults who stutter (AWS) before, directly after, and at least 1 year after an effective intensive fluency-shaping treatment, in 13 typically fluent-speaking control participants (CP), and in 13 males who had spontaneously recovered from stuttering during adulthood (RAWS), while sentences were read aloud with 'neutral', instructed emotional (happy), and linguistically driven (questioning) prosody. These activations were related to speech production acoustics. RESULTS: During pre-treatment prosody generation, the pars orbitalis of the left inferior frontal gyrus and the left anterior insula were activated less in AWS than in CP. The degree of hypo-activation correlated with acoustic measures of dysprosody. Paralleling the near-normalization of free speech melody following fluency-shaping therapy, AWS normalized the inferior frontal hypo-activation, sooner after treatment for generating emotional than linguistic prosody. Unassisted recovery was associated with an additional recruitment of cerebellar resources. CONCLUSIONS: Fluency shaping therapy may restructure prosody, which approaches that of typically fluent-speaking people. Such a process may benefit from additional training of instructed emotional and linguistic prosody by inducing plasticity in the inferior frontal region which has developed abnormally during childhood in PWS.

Advanced voice function assessment: editorial introduction to this special issue.

ICT COST Action 2103 was an EU-funded collaborative network of speech processing engineers, laryngologists, and phoniatricians that started on 19 December 2006 and ended on 18 June 2011. The main objectives were to improve the clinical assessment of voice using new technologies; to encourage clinicians and technologists to work closely together to understand the needs and limitations of each other's fields and, in parallel, to acquire new data with a view to elaborating better voice production models. The papers in this special issue represent some of the outcomes of that partnership. This editorial introduces the background and context for COST Action 2103 and each of the papers. In conclusion we discuss the impact of the Action and what aspects of it may have a lasting effect on practice.

Word stress processing in specific language impairment: auditory or representational deficits?

Word stress processing has repeatedly been reported to be affected in specific language impairment (SLI) with potential consequences for various aspects of language development. However, it still remains unresolved whether word stress impairments in SLI are due to deficits in basic auditory processing or to a degraded phonological representation or both. We addressed this question examining an unselected sample of 10 children with SLI and 11 typically developing (TD) children, aged about 8 years, with respect to their basic auditory processing (duration and skewness discrimination) and phonological representation of prosodic (word stress) and segmental (consonant) contrasts. Our results show lower performance of the SLI group compared to the TD group in all tasks. Crucially, two subgroups of children with SLI emerged from our analyses: While one group was impaired in basic auditory perception, particularly affecting duration discrimination, the other showed no significant auditory processing deficits but a representational impairment.

The anisotropic nature of the human vocal fold: an ex vivo study.

The purpose of this study was to measure the relationship between the shear elastic properties of vocal fold with respect to the direction of applied stress. There is extensive published material that quantifies the shear viscoelastic properties of the vocal fold, but as much of these data were obtained using rotating parallel plate rheometers, which are unable to resolve out difference of the shear elastic behaviour with respect to direction, there is very little data that indicates anisotropic behaviour. To overcome this gap in knowledge, the team devised an apparatus that is capable of applying a shear stress in a known direction. A series of measurements were taken at the mid-membranous position, in the transverse and longitudinal directions. Point-specific measurements were performed using fourteen human cadaver excised larynges, which were hemi-sectioned to expose the vocal fold. An extremely low sinusoidal shear force of 1 g was applied tangentially to the membrane surface in both the longitudinal and transverse direction, and the resultant shear strain was measured. With the probe applied to the intact vocal fold, the average ratio of the elasticity in the transverse with respect to the longitudinal direction was 0.55. Further investigation using histological staining of collagens in the lamina propria indicates that there is a visible difference in the general alignment of collagen fibres when comparing the coronal and the sagittal sections. Our conclusion is that there is a quantifiable difference between the shear elastic response of the lamina propria in the longitudinal and transverse directions, and that this could be explained by the difference in alignment of collagen fibres within the lamina propria.

Biomechanical modeling of register transitions and the role of vocal tract resonators.

Biomechanical modeling and bifurcation theory are applied to study phonation onset and register transition. A four-mass body-cover model with a smooth geometry is introduced to reproduce characteristic features of chest and falsetto registers. Sub- and supraglottal resonances are modeled using a wave-reflection model. Simulations for increasing and decreasing subglottal pressure reveal that the phonation onset exhibits amplitude jumps and hysteresis referring to a subcritical Hopf bifurcation. The onset pressure is reduced due to vocal tract resonances. Hysteresis is observed also for the voice breaks at the chest-falsetto transition. Varying the length of the subglottal resonator has only minor effects on this register transition. Contrarily, supraglottal resonances have a strong effect on the pitch, at which the chest-falsetto transition is found. Experiment of glissando singing shows that the supraglottis has indeed an influence on the register transition.

Feasibility of cardiac gating free of interference with electro-magnetic fields at 1.5 Tesla, 3.0 Tesla and 7.0 Tesla using an MR-stethoscope.

OBJECTIVES: To circumvent the challenges of conventional electrocardiographic (ECG)-gating by examining the efficacy of an MR stethoscope, which offers (i) no risk of high voltage induction or patient burns, (ii) immunity to electromagnetic interference, (iii) suitability for all magnetic field strengths, and (iv) patient comfort together with ease of use for the pursuit of reliable and safe (ultra)high field cardiac gated magnetic resonance imaging (MRI). MATERIALS AND METHODS: The acoustic gating device consists of 3 main components: an acoustic sensor, a signal processing unit, and a coupler unit to the MRI system. Signal conditioning and conversion are conducted outside the 0.5 mT line using dedicated electronic circuits. The final waveform is delivered to the internal physiological signal controller circuitry of a clinical MR scanner. Cardiovascular MRI was performed of normal volunteers (n = 17) on 1.5 T, 3.0 T and 7.0 T whole body MR systems. Black blood imaging, 2D CINE imaging, 3D phase contrast MR angiography, and myocardial T2* mapping were carried out. RESULTS: The MR-stethoscope provided cardiograms at 1.5 T, 3.0 T and 7.0 T free of interference from electromagnetic fields and magneto-hydrodynamic effects. In comparison, ECG waveforms were susceptible to T-wave elevation and other distortions, which were more pronounced at higher fields. Acoustically gated black blood imaging at 1.5 T and 3.0 T provided image quality comparable with or even superior to that obtained from the ECG-gated approach. In the case of correct R-wave recognition, ECG-gated 2D CINE SSFP imaging was found to be immune to cardiac motion effects -even at 3.0 T. However, ECG-gated 2D SSFP CINE imaging was prone to cardiac motion artifacts if R-wave mis-registration occurred because of T-wave elevation. Acoustically gated 3D PCMRA at 1.5 T, 3.0 T and 7.0 T resulted in images free of blood pulsation artifacts because the acoustic gating approach provided cardiac signal traces free of interference with electromagnetic fields or magneto-hydrodynamic effects even at 7.0 Tesla. Severe ECG-trace distortions and T-wave elevations occurred at 3.0 T and 7.0 T. Acoustically cardiac gated T2* mapping at 3.0 T yielded a T2* value of 22.3 +/- 4.8 ms for the inferoseptal myocardium. CONCLUSIONS: The proposed MR-stethoscope presents a promising alternative to currently available techniques for cardiac gating of (ultra)high field MRI. Its intrinsic insensitivity to interference from electromagnetic fields renders it suitable for clinical imaging because of its excellent trigger reliability, even at 7.0 Tesla.

Pathogenesis of vocal fold nodules: new insights from a modelling approach.

OBJECTIVE: To give new insights into the pathogenesis of vocal fold nodules: (a) why the female/male ratio is so extreme, (b) how an hourglass-shaped vibration pattern - eliciting a localized microtrauma - originates, and (c) what the roles of muscular tension imbalance and of behavioral aspects are. MATERIALS AND METHODS: Simulations with a 3-dimensional computer model of the vibrating vocal folds. RESULTS AND CONCLUSION: (1) A slightly incomplete dorsal vocal fold adduction is a first condition for inducing an hourglass vibration pattern. (2) A limited collision zone is only possible with a small degree of curving of the rest position of the vocal fold edges in their ventral portion. This is an anatomical characteristic of the adult female larynx. Muscular fatigue and resulting hypotonia seem to enhance this curving. (3) If both these conditions are fulfilled, a sufficient vibration amplitude is required to achieve a localized impact. (4) This third condition can be obtained by an increased subglottal pressure and/or by a decrease in active stress of the tension forces between the neighboring vocalis masses. These last aspects incorporate muscular tension imbalance (dyskinesia) and behavioral aspects in the modelling process. Decrease in active stress is a possible effect of fatigue, and increase in subglottal pressure a result of effort compensation.

A method for measurement of the vocal tract impedance at the mouth.

In this contribution a method is presented for the measurement of vocal tract resonances. The technique uses a non-invasive acoustic excitation of the vocal tract and a fast and robust detection. The method is an alternative to the linear predictive coding (LPC) analysis for patients with voice and speech disorders. Sweep signals are emitted and recorded simultaneously from the small end of a tube placed in front of the mouth opening. The use of a pressure sensor and a velocity sensor provides a direct measurement of the vocal tract impedance at the mouth (VTMI). For selected sustained German vowels, and some consonants, a comparison of results from LPC analysis and VTMI measurements is given. The results indicate a good agreement in the frequency range from 500 to 5,000 Hz. The feasibility of the VTMI method for diagnostic and therapeutic applications is subject to current research.