National Center for Voice and Speech

Denver, CO, United States

National Center for Voice and Speech

Denver, CO, United States
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Narayana S.,University of Texas Health Science Center at San Antonio | Fox P.T.,University of Texas Health Science Center at San Antonio | Fox P.T.,South Texas Veterans Administration Medical Center | Zhang W.,University of Texas Health Science Center at San Antonio | And 6 more authors.
Human Brain Mapping | Year: 2010

LSVTV® LOUD (Lee Silverman Voice Treatment) is efficacious in the treatment of speech disorders in idiopathic Parkinson's disease (IPD), particularly hypophonia. Functional imaging in patients with IPD has shown abnormalities in several speech regions and changes in these areas immediately following treatment. This study serves to extend the analysis by correlating changes of regional neural activity with the main behavioral change following treatment, namely, increased vocal intensity. Ten IPD participants with hypophonia were studied before and after LSVT LOUD. Cerebral blood flow during rest and reading conditions were measured by H2 15O- positron emission tomography. Z-score images were generated by contrasting reading with rest conditions for pre- and post-LSVT LOUD sessions. Neuronal activity during reading in the pre- versus post-LSVT LOUD contrast was correlated with corresponding change in vocal intensity to generate correlation images. Behaviorally, vocal intensity for speech tasks increased significantly after LSVT LOUD. The contrast and correlation analyses indicate a treatment-dependent shift to the right hemisphere with modification in the speech motor regions as well as in prefrontal and temporal areas. We interpret the modification of activity in these regions to be a top-down effect of LSVT LOUD. The absence of an effect of LSVT LOUD on the basal ganglion supports this argument. Our findings indicate that the therapeutic effect of LSVT LOUD in IPD hypophonia results from a shift in cortical activity to the right hemisphere. These findings demonstrate that the short-term changes in the speech motor and multimodal integration areas can occur in a top-down manner. © 2009 Wiley-Liss, Inc.

Mahler L.A.,University of Rhode Island | Ramig L.O.,University of Colorado at Boulder | Ramig L.O.,National Center for Voice and Speech
Clinical Linguistics and Phonetics | Year: 2012

This study investigated the impact of a well-defined behavioral dysarthria treatment on acoustic and perceptual measures of speech in four adults with dysarthria secondary to stroke. A single-subject ABA experimental design was used to measure the effects of the Lee Silverman Voice Treatment (LSVT ® LOUD) on the speech of individual participants. Dependent measures included vocal sound pressure level, phonatory stability, vowel space area, and listener ratings of speech, voice and intelligibility. Statistically significant improvements (p < 0.05) in vocal dB SPL and phonatory stability as well as larger vowel space area were present for all participants. Listener ratings suggested improved voice quality and more natural speech post-treatment. Speech intelligibility scores improved for one of four participants. These data suggest that people with dysarthria secondary to stroke can respond positively to intensive speech treatments such as LSVT. Further studies are needed to investigate speech treatments specific to stroke. © 2012 Informa UK, Ltd.

Riede T.,University of Utah | Riede T.,National Center for Voice and Speech | Lingle S.,University of Winnipeg | Hunter E.J.,National Center for Voice and Speech | And 2 more authors.
Journal of Morphology | Year: 2010

The authors test the hypothesis that vocal fold morphology and biomechanical properties covary with species-specific vocal function. They investigate mule deer (Odocoileus hemionus) vocal folds, building on, and extending data on a related cervid, the Rocky Mountain elk (Cervus elaphus nelsoni). The mule deer, in contrast to the elk, is a species with relatively little vocal activity in adult animals. Mule deer and elk vocal folds show the typical three components of the mammalian vocal fold (epithelium, lamina propria and thyroarytenoid muscle). The vocal fold epithelium and the lamina propria were investigated in two sets of tensile tests. First, creep rupture tests demonstrated that ultimate stress in mule deer lamina propria is of the same magnitude as in elk. Second, cyclic loading tests revealed similar elastic moduli for the vocal fold epithelium in mule deer and elk. The elastic modulus of the lamina propria is also similar between the two species in the low-strain region, but differs at strains larger than 0.3. Sex differences in the stress-strain response, which have been reported for elk and human vocal folds, were not found for mule deer vocal folds. The laminae propriae in mule deer and elk vocal folds are comparatively large. In general, a thick and uniformly stiff lam-ina propria does not self-oscillate well, even when high subglottic pressure is applied. If the less stiff vocal fold seen in elk is associated with a differentiated lamina propria it would allow the vocal fold to vibrate at high tension and high subglottic pressure. The results of this study support the hypothesis that viscoelastic properties of vocal folds varies with function and vocal behavior. © 2009 Wiley-Liss, Inc.

Titze I.R.,National Center for Voice and Speech | Titze I.R.,University of Iowa | Titze I.R.,University of Utah
Journal of the Acoustical Society of America | Year: 2014

The origin of vocal registers has generally been attributed to differential activation of cricothyroid and thyroarytenoid muscles in the larynx. Register shifts, however, have also been shown to be affected by glottal pressures exerted on vocal fold surfaces, which can change with loudness, pitch, and vowel. Here it is shown computationally and with empirical data that intraglottal pressures can change abruptly when glottal adductory geometry is changed relatively smoothly from convergent to divergent. An intermediate shape between large convergence and large divergence, namely, a nearly rectangular glottal shape with almost parallel vocal fold surfaces, is associated with mixed registration. It can be less stable than either of the highly angular shapes unless transglottal pressure is reduced and upper stiffness of vocal fold tissues is balanced with lower stiffness. This intermediate state of adduction is desirable because it leads to a low phonation threshold pressure with moderate vocal fold collision. Achieving mixed registration consistently across wide ranges of F0, lung pressure, and vocal tract shapes appears to be a balancing act of coordinating laryngeal muscle activation with vocal tract pressures. Surprisingly, a large transglottal pressure is not facilitative in this process, exacerbating the bi-stable condition and the associated register contrast. © 2014 Acoustical Society of America.

Titze I.R.,National Center for Voice and Speech | Titze I.R.,University of Iowa
Journal of the Acoustical Society of America | Year: 2015

It is well known that a half-sinusoid has no odd harmonics other than the fundamental. If glottal flow in phonation were to approximate this exact waveshape, which is generally unlikely, some misperception of pitch and loss of vowel intelligibility would occur. The sensitivity of the glottal waveshape to this special shape is explored by systematically varying two parameters, open quotient and skewing quotient. Mild asymmetry (open quotient below 0.45 or above 0.55 and/or skewing quotient greater than 2.0) equalizes the odd-even harmonic series. Singers and speakers avoid the exact symmetry by skewing the flow pulse with source-filter interaction. © 2015 Acoustical Society of America.

Tsanas A.,University of Oxford | Little M.A.,Massachusetts Institute of Technology | Fox C.,University of Colorado at Boulder | Fox C.,National Center for Voice and Speech | And 2 more authors.
IEEE Transactions on Neural Systems and Rehabilitation Engineering | Year: 2014

Vocal performance degradation is a common symptom for the vast majority of Parkinson's disease (PD) subjects, who typically follow personalized one-to-one periodic rehabilitation meetings with speech experts over a long-term period. Recently, a novel computer program called Lee Silverman voice treatment (LSVT) Companion was developed to allow PD subjects to independently progress through a rehabilitative treatment session. This study is part of the assessment of the LSVT Companion, aiming to investigate the potential of using sustained vowel phonations towards objectively and automatically replicating the speech experts' assessments of PD subjects' voices as 'acceptable' (a clinician would allow persisting during in-person rehabilitation treatment) or 'unacceptable' (a clinician would not allow persisting during in-person rehabilitation treatment). We characterize each of the 156 sustained vowel /a/ phonations with 309 dysphonia measures, select a parsimonious subset using a robust feature selection algorithm, and automatically distinguish the two cohorts (acceptable versus unacceptable) with about 90% overall accuracy. Moreover, we illustrate the potential of the proposed methodology as a probabilistic decision support tool to speech experts to assess a phonation as 'acceptable' or 'unacceptable.' We envisage the findings of this study being a first step towards improving the effectiveness of an automated rehabilitative speech assessment tool. © 2001-2011 IEEE.

Tsanas A.,University of Oxford | Zanartu M.,Federico Santa María Technical University | Little M.A.,Massachusetts Institute of Technology | Fox C.,National Center for Voice and Speech | And 2 more authors.
Journal of the Acoustical Society of America | Year: 2014

There has been consistent interest among speech signal processing researchers in the accurate estimation of the fundamental frequency (F0) of speech signals. This study examines ten F0 estimation algorithms (some well-established and some proposed more recently) to determine which of these algorithms is, on average, better able to estimate F0 in the sustained vowel /a/. Moreover, a robust method for adaptively weighting the estimates of individual F0 estimation algorithms based on quality and performance measures is proposed, using an adaptive Kalman filter (KF) framework. The accuracy of the algorithms is validated using (a) a database of 117 synthetic realistic phonations obtained using a sophisticated physiological model of speech production and (b) a database of 65 recordings of human phonations where the glottal cycles are calculated from electroglottograph signals. On average, the sawtooth waveform inspired pitch estimator and the nearly defect-free algorithms provided the best individual F0 estimates, and the proposed KF approach resulted in a ∼16% improvement in accuracy over the best single F0 estimation algorithm. These findings may be useful in speech signal processing applications where sustained vowels are used to assess vocal quality, when very accurate F0 estimation is required. © 2014 Acoustical Society of America.

Fox C.M.,National Center for Voice and Speech | Boliek C.A.,University of Alberta
Journal of Speech, Language, and Hearing Research | Year: 2012

Purpose: The purpose of this study was to examine the effects of an intensive voice treatment (Lee Silverman Voice Treatment, commonly known as LSVT LOUD) for children with spastic cerebral palsy (CP) and dysarthria. Method: A nonconcurrent multiple baseline single-subject design with replication across 5 children with spastic CP was used. Auditory-perceptual analysis of speech, acoustic measures of vocal functioning, and perceptual ratings by parents of participants were obtained at baseline, posttreatment, and 6-week follow-up recording sessions. Results: Listeners consistently preferred the speech samples taken immediately posttreatment over those taken during the baseline phase for most perceptual characteristics rated in this study. Changes in acoustic measures of vocal functioning were not consistent across participants and occurred more frequently for maximum performance tasks as opposed to speech. Although parents of the treated participants reported an improved perception of vocal loudness immediately following treatment, maintenance of changes at 6-week follow-up varied across the participants. No changes were observed in the 5th participant, who did not receive treatment. Conclusions: These findings provide some preliminary observations that the children with spastic CP in this study not only tolerated intensive voice treatment but also showed improvement on select aspects of vocal functioning. These outcomes warrant further research through Phase 2 treatment studies. © American Speech-Language-Hearing Association.

Sapir S.,Haifa University | Ramig L.O.,University of Colorado at Boulder | Spielman J.L.,University of Colorado at Boulder | Fox C.,National Center for Voice and Speech
Journal of Speech, Language, and Hearing Research | Year: 2010

Purpose: The vowel space area (VSA) has been used as an acoustic metric of dysarthric speech, but with varying degrees of success. In this study, the authors aimed to test an alternative metric to the VSA-the formant centralization ratio (FCR), which is hypothesized to more effectively differentiate dysarthric from healthy speech and register treatment effects. Method: Speech recordings of 38 individuals with idiopathic Parkinson's disease and dysarthria (19 of whom received 1 month of intensive speech therapy [Lee Silverman Voice Treatment; LSVT LOUD]) and 14 healthy control participants were acoustically analyzed. Vowels were extracted from short phrases. The same vowelformant elementswere used to construct the FCR, expressed as (F2u+F2A +F1i+F1u)/(F2i + F1A), the VSA, expressed as ABS([F1i × (F2A - F2u) + F1A × (F2u - F2i) + F1u × (F2i - F2A)]/2), a logarithmically scaled version of the VSA (LnVSA), and the F2i/F2u ratio. Results: Unlike the VSA and the LnVSA, the FCR and F2i/F2u ratio robustly differentiated dysarthric from healthy speech and were not gender sensitive. All metrics effectively registered treatment effects and were strongly correlated with each other. Conclusion: Albeit preliminary, the present findings indicate that the FCR is a sensitive, valid, and reliable acoustic metric for distinguishing dysarthric from unimpaired speech and for monitoring treatment effects, probably because of reduced sensitivity to interspeaker variability and enhanced sensitivity to vowel centralization. © American Speech-Language-Hearing Association.

Tsanas A.,University of Oxford | Tsanas A.,Oxford Centre for Industrial and Applied Mathematics | Little M.A.,University of Oxford | Little M.A.,Oxford Centre for Industrial and Applied Mathematics | And 3 more authors.
Journal of the Royal Society Interface | Year: 2011

The standard reference clinical score quantifying average Parkinson's disease (PD) symptom severity is the Unified Parkinson's Disease Rating Scale (UPDRS). At present, UPDRS is determined by the subjective clinical evaluation of the patient's ability to adequately cope with a range of tasks. In this study, we extend recent findings that UPDRS can be objectively assessed to clinically useful accuracy using simple, self-administered speech tests, without requiring the patient's physical presence in the clinic. We apply a wide range of known speech signal processing algorithms to a large database (approx. 6000 recordings from 42 PD patients, recruited to a six-month, multi-centre trial) and propose a number of novel, nonlinear signal processing algorithms which reveal pathological characteristics in PD more accurately than existing approaches. Robust feature selection algorithms select the optimal subset of these algorithms, which is fed into non-parametric regression and classification algorithms, mapping the signal processing algorithm outputs to UPDRS. We demonstrate rapid, accurate replication of the UPDRS assessment with clinically useful accuracy (about 2 UPDRS points difference from the clinicians' estimates, p < 0.001). This study supports the viability of frequent, remote, cost-effective, objective, accurate UPDRS telemonitoring based on self-administered speech tests. This technology could facilitate large-scale clinical trials into novel PD treatments. © 2010 The Royal Society.

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