Human brain activation during phonation and exhalation: common volitional control for two upper airway functions.
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Phonation is defined as a laryngeal motor behavior used for speech production, which involves a highly specialized coordination of laryngeal and respiratory neuromuscular control. During speech, brief periods of vocal fold vibration for vowels are interspersed by voiced and unvoiced consonants, glottal stops and glottal fricatives (/h/). It remains unknown whether laryngeal/respiratory coordination of phonation for speech relies on separate neural systems from respiratory control or whether a common system controls both behaviors. To identify the central control system for human phonation, we used event-related fMRI to contrast brain activity during phonation with activity during prolonged exhalation in healthy adults. Both whole-brain analyses and region of interest comparisons were conducted. Production of syllables containing glottal stops and vowels was accompanied by activity in left sensorimotor, bilateral temporoparietal and medial motor areas. Prolonged exhalation similarly involved activity in left sensorimotor and temporoparietal areas but not medial motor areas. Significant differences between phonation and exhalation were found primarily in the bilateral auditory cortices with whole-brain analysis. The ROI analysis similarly indicated task differences in the auditory cortex with differences also detected in the inferolateral motor cortex and dentate nucleus of the cerebellum. A second experiment confirmed that activity in the auditory cortex only occurred during phonation for speech and did not depend upon sound production. Overall, a similar central neural system was identified for both speech phonation and voluntary exhalation that primarily differed in auditory monitoring. (+info)
Profiles of vocal development in young cochlear implant recipients.
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PURPOSE: The main purpose of this investigation was to examine the effects of cochlear implant experience on prelinguistic vocal development in young deaf children. Procedure A prospective longitudinal research design was used to document the sequence and time course of vocal development in 7 children who were implanted between 10 and 36 months of age. Speech samples were collected twice before implant activation and on a monthly basis thereafter for up to 2 years. Children's vocalizations were classified according to the levels of the Stark Assessment of Early Vocal Development--Revised (SAEVD-R; S. Nathani, D. J Ertmer, & R. E. Stark, 2006). RESULTS: The main findings were (a) 6 of 7 children made advancements in vocal development after implantation; (b) children implanted between 12 and 36 months progressed through SAEVD-R levels in the predicted sequence, whereas a child implanted at a younger age showed a different sequence; (c) milestones in vocal development were often achieved with fewer months of hearing experience than observed in typically developing infants and appeared to be influenced by age at implantation; and (d) in general, children implanted at younger ages completed vocal development at younger chronological ages than those implanted later in life. Specific indicators of benefit from implant use were also identified. CONCLUSION: The time course of vocal development in young cochlear implant recipients can provide clinically useful information for assessing the benefits of implant experience. Studies of postimplantation vocal development have the potential to inform theories of spoken language development. (+info)
Vibratory regime classification of infant phonation.
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Infant phonation is highly variable in many respects, including the basic vibratory patterns by which the vocal tissues create acoustic signals. Previous studies have identified the regular occurrence of nonmodal phonation types in normal infant phonation. The glottis is like many oscillating systems that, because of nonlinear relationships among the elements, may vibrate in ways representing the deterministic patterns classified theoretically within the mathematical framework of nonlinear dynamics. The infant's preverbal vocal explorations present such a variety of phonations that it may be possible to find effectively all the classes of vibration predicted by nonlinear dynamic theory. The current report defines acoustic criteria for an important subset of such vibratory regimes, and demonstrates that analysts can be trained to reliably use these criteria for a classification that includes all instances of infant phonation in the recorded corpora. The method is thus internally comprehensive in the sense that all phonations are classified, but it is not exhaustive in the sense that all vocal qualities are thereby represented. Using the methods thus developed, this study also demonstrates that the distributions of these phonation types vary significantly across sessions of recording in the first year of life, suggesting developmental changes. The method of regime classification is thus capable of tracking changes that may be indicative of maturation of the mechanism, the learning of categories of phonatory control, and the possibly varying use of vocalizations across social contexts. (+info)
Discovery of a low frequency sound source in Mysticeti (baleen whales): anatomical establishment of a vocal fold homolog.
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The mechanism of mysticete (baleen whale) vocalization has remained a mystery. Vocal folds (true vocal "cords"), the structures responsible for sound production in terrestrial mammals, were thought to be absent in whales. This study tests the hypothesis that the mysticete larynx possesses structures homologous to vocal folds and that they are capable of sound generation. Laryngeal anatomy was examined in 37 specimens representing 6 mysticete species. Results indicate the presence of a U-shaped fold (U-fold) in the lumen of the larynx. The U-fold is supported by arytenoid cartilages, controlled by skeletal muscles innervated by the recurrent laryngeal nerve, is adjacent to a diverticulum (laryngeal sac) covered with mucosa innervated by the superior laryngeal nerve, and contains a ligament-conditions that also define the vocal folds of terrestrial mammals and, therefore, supports homology. Unlike the vocal folds of terrestrial mammals, which are perpendicular to airflow, the mysticete U-fold is oriented parallel to airflow. U-fold adduction/abduction and elevation/depression may control airflow, and vibration of its edges may generate sounds. The walls of the laryngeal sac can expand and contract, may serve as a resonant space, and may also propagate vibrations generated by movements of the supporting arytenoid cartilages. The extensive musculature surrounding the laryngeal sac may enable rapid and forceful expulsion of air from the lumen of the sac into other respiratory spaces, or maintain a constant sac volume despite the effects of ambient pressure (e.g., changes during diving or ascent). The size and complexity of the mysticete larynx indicates an organ with multiple functions, including protection during breathing/swallowing, regulation of airflow and pressures in the respiratory spaces, and sound generation. The presence of a vocal fold homolog offers a new insight into both the mechanism of sound generation by mysticetes and the divergent evolution of odontocete and mysticete cetaceans. (+info)
Effect of cues to increase sound pressure level on respiratory kinematic patterns during connected speech.
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PURPOSE: This study examined the response of the respiratory system to 3 cues used to elicit increased vocal loudness to determine whether the effects of cueing, shown previously in sentence tasks, were present in connected speech tasks and to describe differences among tasks. METHOD: Fifteen young men and 15 young women produced a 2-paragraph reading passage in response to 4 different loudness cues: comfortable loudness level, targeting 10 dB above comfortable, at what they perceived as twice their comfortable loudness, and with multitalker noise present in the background. A short monologue was produced at comfortable loudness level and with noise in the background. RESULTS: Differences in respiratory strategies were demonstrated for the different cueing conditions, similar to patterns observed in sentence productions. The kinematic patterns were similar for reading and monologue; however, utterances were longer and speaking rate was slower in the monologue task. CONCLUSION: The findings extend the results from sentences to connected speech and provide support for the hypothesis that "intention" or goals play a role in the control of respiratory function during speech. Respiratory kinematics were similar across tasks, when the same cue was used, except for differences related to breath group length and speech rate. (+info)
Time dependence of vocal tract modes during production of vowels and vowel sequences.
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Vocal tract shaping patterns based on articulatory fleshpoint data from four speakers in the University of Wisconsin x-ray microbeam (XRMB) database [J. Westbury, UW-Madison, (1994)] were determined with a principal component analysis (PCA). Midsagittal cross-distance functions representative of approximately the front 6 cm of the oral cavity for each of 11 vowels and vowel-vowel (VV) sequences were obtained from the pellet positions and the hard palate profile for the four speakers. A PCA was independently performed on each speaker's set of cross-distance functions representing static vowels only, and again with time-dependent cross-distance functions representing vowels and VV sequences. In all cases, results indicated that the first two orthogonal components (referred to as modes) accounted for more than 97% of the variance in each speaker's set of cross-distance functions. In addition, the shape of each mode was shown to be similar across the speakers suggesting that the modes represent common patterns of vocal tract deformation. Plots of the resulting time-dependent coefficient records showed that the four speakers activated each mode similarly during production of the vowel sequences. Finally, a procedure was described for using the time-dependent mode coefficients obtained from the XRMB data as input for an area function model of the vocal tract. (+info)
Reverse phonation--physiologic and clinical aspects of this speech voice therapy modality.
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Reverse phonation is the voice production during inspiration, accomplished spontaneously in situations such as when a person sighs. AIM: to do a literature review, describing discoveries related to the use of the reverse phonation in the clinical practice, the anatomy and physiology of its production and its effects in vocal treatments; and moreover, indications and problems of the technique for speech disorders treatment and voice enhancement. RESULTS: there were reports of significant changes in vocal treatment during with the use of reverse phonation: ventricular distention, ventricular folds separation, increase in the fundamental frequency, mucous wave inverse movement; and it also facilitates the dynamic study of the larynx when associated with endoscopy, making it possible to have a better definition of lesion localization in vocal folds superficial lamina propria layers. CONCLUSION: There are few studies describing larynx behavior during reverse phonation and, for this technique to be used in a more precise and objective way, more studies are necessary in order to prove its effectiveness in practical matters. (+info)
Tongue movement kinematics in long and short Japanese consonants.
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This paper examines tongue movements in stop and fricative consonants where the duration of the oral closure/constriction for the consonant is varied for linguistic purposes. Native speakers of Japanese served as subjects. The linguistic material consisted of Japanese word pairs that only differed in the duration of the lingual consonant, which was either long or short. Recordings were made of tongue movements using a magnetometer system. Results show a robust difference in closure duration between the long and short consonants. Overall, the path of the tongue movement during the consonant was longer for the long than for the short consonant. All speakers decreased the speed of the tongue movement during the long consonant. These adjustments in tongue movements were most likely made to maintain the contact between the tongue and the palate for the closure and constriction. (+info)