Training to use voice onset time as a cue to talker identification induces a left-ear/right-hemisphere processing advantage.
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We examined the effect of perceptual training on a well-established hemispheric asymmetry in speech processing. Eighteen listeners were trained to use a within-category difference in voice onset time (VOT) to cue talker identity. Successful learners (n=8) showed faster response times for stimuli presented only to the left ear than for those presented only to the right. The development of a left-ear/right-hemisphere advantage for processing a prototypically phonetic cue supports a model of speech perception in which lateralization is driven by functional demands (talker identification vs. phonetic categorization) rather than by acoustic stimulus properties alone. (+info)
Making non-fluent aphasics speak: sing along!
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A classic observation in neurology is that aphasics can sing words they cannot pronounce otherwise. To further assess this claim, we investigated the production of sung and spoken utterances in eight brain-damaged patients suffering from a variety of speech disorders as a consequence of a left-hemisphere lesion. In Experiment 1, the patients were tested in the repetition and recall of words and notes of familiar material. Lyrics of familiar songs, as well as words of proverbs and prayers, were not better pronounced in singing than in speaking. Notes were better produced than words. In Experiment 2, the aphasic patients repeated and recalled lyrics from novel songs. Again, they did not produce more words in singing than in speaking. In Experiment 3, when allowed to sing or speak along with an auditory model while learning novel songs, aphasics repeated and recalled more words when singing than when speaking. Reduced speed or shadowing cannot account for this advantage of singing along over speaking in unison. The results suggest that singing in synchrony with an auditory model--choral singing--is more effective than choral speech, at least in French, in improving word intelligibility because choral singing may entrain more than one auditory-vocal interface. Thus, choral singing appears to be an effective means of speech therapy. (+info)
How far, how long: on the temporal scope of prosodic boundary effects.
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Acoustic lengthening at prosodic boundaries is well explored, and the articulatory bases for this lengthening are becoming better understood. However, the temporal scope of prosodic boundary effects has not been examined in the articulatory domain. The few acoustic studies examining the distribution of lengthening indicate that boundary effects extend from one to three syllables before the boundary, and that effects diminish as distance from the boundary increases. This diminishment is consistent with the pi-gesture model of prosodic influence [Byrd and Saltzman, J. Phonetics 31, 149-180 (2003)]. The present experiment tests the preboundary and postboundary scope of articulatory lengthening at an intonational phrase boundary. Movement-tracking data are used to evaluate durations of consonant closing and opening movements, acceleration durations, and consonant spatial magnitude. Results indicate that prosodic boundary effects exist locally near the phrase boundary in both directions, diminishing in magnitude more remotely for those subjects who exhibit extended effects. Small postboundary effects that are compensatory in direction are also observed. (+info)
Interarticulator programming: effects of closure duration on lip and tongue coordination in Japanese.
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This paper examines the coordination of lip and tongue movements in sequences of vowel-bilabial consonant-vowel where the duration of the oral closure 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 labial consonant, which was either long or short. Recordings were made of lip and tongue movements using a magnetometer system. Results show a robust difference in closure duration between the long and short consonants. The tongue movement from the first to the second vowel had a longer duration in the long than in the short consonants, and its average speed was slower in the long consonant. The size of the tongue movement path between the vowels did not consistently differ between the long and short consonants. The tongue movement almost always started before the oral closure for the consonant, while the onset of the lip movement towards oral closure mostly started before that of the tongue movement. The offset of the tongue movement occurred after the release of the closure, but there was no clear pattern for the long and short consonants. (+info)
Residual signal auto-correlation to evaluate speech in Parkinson's disease patients.
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OBJECTIVE: To evaluate the maximum residual signal auto-correlation also known as pitch amplitude (PA) values in patients with Parkinson's disease (PD) patients. METHOD: The signals of 21 Parkinson's patients were compared with 15 healthy individuals, divided according age and gender. RESULTS: Statistical difference was seen between groups for PA, 0.39 for controls and 0.25 for PD. Normal value threshold was set as 0.3; (p<0.001). In the Parkinson's group 80.77%, and in the control group only 12.28%, had a PA<0.3 demonstrating an association between these variables. The dispersion diagram for age and PA for PD individuals showed p=0.01 and r=0.54. There was no significant difference in relation to gender and PA between groups. CONCLUSION: The significant differences in pitchs amplitude between PD patients and healthy individuals demonstrate the methods specificity. The results showed the need of prospective controlled studies to improve the use and indications of residual signal auto-correlation to evaluate speech in PD patients. (+info)
Discrimination of starting phase with sinusoidal envelope modulation.
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Modulation-filterbank models discard phase information above very low rates of amplitude modulation (AM). The present work evaluated this restriction by measuring thresholds for discriminating the starting phase of sinusoidal modulators of wideband-noise carriers. Results showed a low-pass characteristic with some listeners unable to perform the task once the modulation rate was greater than 12.5 Hz. For others, however, thresholds were obtained with AM rates of up to one to two octaves higher. Intersubject variability may in part relate to the presence of multiple discrimination cues, with only some based on comparison of the ongoing pattern of envelope fluctuation. (+info)
Phonatory effects of supraglottic structures in excised canine larynges.
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The aim of this study is to determine how phonation is affected by the presence and by alteration in the position of the supraglottic structures. The study used three excised canine larynges. A series of pressure-flow experiments were completed first on the excised larynx with false folds and epiglottis intact, then with the epiglottis removed, and finally with the false folds removed. Aerodynamic and acoustic effects were quantified with the analysis of the pressure, flow, and audio signals. The results of the study indicated that (1) elevation of the epiglottis to upright position from a horizontal position decreased subglottal pressure, increased flow (decreased laryngeal resistance), and slightly decreased fundamental frequency; (2) vibration of the false vocal folds induced some irregularity into the acoustic output of the larynx; (3) the presence of the epiglottis and the false vocal folds enhanced the second partial of the acoustic signal; and (4) the absence of the epiglottis and false folds increased low-frequency noise (between 0 and 300 Hz). Alteration in the position of the supraglottic structures affects laryngeal aerodynamics and acoustics, possibly due to biomechanical linkage with true vocal folds. When the supraglottic structures are present they act as resonators, enhancing the second partial and when they are absent (as in persons with supraglottic laryngectomy), low-frequency noise is increased perhaps due to the loss of boundary conditions or due to the presence of loose tissue. (+info)
Vortical flow field during phonation in an excised canine larynx model.
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OBJECTIVES: To more fully understand the mechanisms of vocal fold vibration and sound production, we studied the velocity flow fields above the folds. Such velocity fields during phonation have not been reported in the literature. METHODS: Using the particle image velocimetry method for 3 excised canine larynges, we obtained the velocity fields in the mid-membranous coronal plane during different phases of phonation. The velocity field was determined synchronously with the vocal fold motion recorded by high-speed videography. RESULTS: The results show that vortices occur immediately above the vocal folds and that the location and shape of the vortices depend on the phase of the phonation cycle. Consistent vortical structures found included starting vortices, Kelvin-Helmholtz vortices, entrainment vortices, and vortices directly above the folds during the divergent glottal stage. CONCLUSIONS: These vortical structures were consistently found during specific phases of the glottal cycle for 3 canine larynges that significantly varied in size. This consistent behavior suggests that the vortices may be important for both vibration and sound production; however, further study is needed to prove this. The clinical significance of these vortices is discussed. (+info)