scholarly journals Effects of vowel context, stimulus length, and age on nasalance scores

2016 ◽  
Vol 8 (3) ◽  
pp. 111-116 ◽  
Author(s):  
Il San Shin ◽  
Seunghee Ha
Keyword(s):  
Vowel Context ◽  
Context Stimulus ◽  
Stimulus Length

Relationships Between Subjective Ratings and Objective Measures of Performance in Speechreading Sentences

1997 ◽  
Vol 40 (4) ◽  
pp. 900-911 ◽  
Author(s):  
Marilyn E. Demorest ◽  
Lynne E. Bernstein
Keyword(s):  
Hearing Impairment ◽  
Performance Evaluations ◽  
Objective Measures ◽  
Large Individual ◽  
Subjective Ratings ◽  
Objective Performance ◽  
Phonetic Distance ◽  
Stimulus Length ◽  
Measures Of Performance ◽  
Confidence Scale

Ninety-six participants with normal hearing and 63 with severe-to-profound hearing impairment viewed 100 CID Sentences (Davis & Silverman, 1970) and 100 B-E Sentences (Bernstein & Eberhardt, 1986b). Objective measures included words correct, phonemes correct, and visual-phonetic distance between the stimulus and response. Subjective ratings were made on a 7-point confidence scale. Magnitude of validity coefficients ranged from .34 to .76 across materials, measures, and groups. Participants with hearing impairment had higher levels of objective performance, higher subjective ratings, and higher validity coefficients, although there were large individual differences. Regression analyses revealed that subjective ratings are predictable from stimulus length, response length, and objective performance. The ability of speechreaders to make valid performance evaluations was interpreted in terms of contemporary word recognition models.

Lip and Jaw Kinematics in Bilabial Stop Consonant Production

1997 ◽  
Vol 40 (4) ◽  
pp. 877-893 ◽  
Author(s):  
Anders Löfqvist ◽  
Vincent L. Gracco
Keyword(s):  
Control Strategy ◽  
High Velocity ◽  
Stop Consonant ◽  
Movement Variability ◽  
Upper Lip ◽  
Lower Lip ◽  
Vowel Context ◽  
Virtual Target ◽  
Contextual Variability ◽  
Consonant Voicing

This paper reports two experiments, each designed to clarify different aspects of bilabial stop consonant production. The first one examined events during the labial closure using kinematic recordings in combination with records of oral air pressure and force of labial contact. The results of this experiment suggested that the lips were moving at a high velocity when the oral closure occurred. They also indicated mechanical interactions between the lips during the closure, including tissue compression and the lower lip moving the upper lip upward. The second experiment studied patterns of upper and lower lip interactions, movement variability within and across speakers, and the effects on lip and jaw kinematics of stop consonant voicing and vowel context. Again, the results showed that the lips were moving at a high velocity at the onset of the oral closure. No consistent influences of stop consonant voicing were observed on lip and jaw kinematics in five subjects, nor on a derived measure of lip aperture. The overall results are compatible with the hypothesis that one target for the lips in bilabial stop production is a region of negative lip aperture. A negative lip aperture implies that to reach their virtual target, the lips would have to move beyond each other. Such a control strategy would ensure that the lips will form an air tight seal irrespective of any contextual variability in the onset positions of their closing movements.

The Impact of Lexical and Articulatory Factors in the Automatic Selection of Test Materials for a Web-Based Assessment of Intelligibility in Dysarthria

2021 ◽  
pp. 1-17
Author(s):  
Katharina Lehner ◽  
Wolfram Ziegler
Keyword(s):  
Clinical Examination ◽  
Clinical Assessment ◽  
Large Scale ◽  
Assessment Tool ◽  
Word Class ◽  
Neighborhood Structure ◽  
Test Materials ◽  
Stimulus Length ◽  
The Impact ◽  
Target Words

Purpose The clinical assessment of intelligibility must be based on a large repository and extensive variation of test materials, to render test stimuli unpredictable and thereby avoid expectancies and familiarity effects in the listeners. At the same time, it is essential that test materials are systematically controlled for factors influencing intelligibility. This study investigated the impact of lexical and articulatory characteristics of quasirandomly selected target words on intelligibility in a large sample of dysarthric speakers under clinical examination conditions. Method Using the clinical assessment tool KommPaS , a total of 2,700 sentence-embedded target words, quasirandomly drawn from a large corpus, were spoken by a group of 100 dysarthric patients and later transcribed by listeners recruited via online crowdsourcing. Transcription accuracy was analyzed for influences of lexical frequency, phonological neighborhood structure, articulatory complexity, lexical familiarity, word class, stimulus length, and embedding position. Classification and regression analyses were performed using random forests and generalized linear mixed models. Results Across all degrees of severity, target words with higher frequency, fewer and less frequent phonological neighbors, higher articulatory complexity, and higher lexical familiarity received significantly higher intelligibility scores. In addition, target words were more challenging sentence-initially than in medial or final position. Stimulus length had mixed effects; word length and word class had no effect. Conclusions In a large-scale clinical examination of intelligibility in speakers with dysarthria, several well-established influences of lexical and articulatory parameters could be replicated, and the roles of new factors were discussed. This study provides clues about how experimental rigor can be combined with clinical requirements in the diagnostics of communication impairment in patients with dysarthria.

Apparent diffusion time of oxygen from blood to tissue in rat cerebral cortex: implication for tissue oxygen dynamics during brain functions

2007 ◽  
Vol 103 (4) ◽  
pp. 1352-1358 ◽  
Author(s):  
Kazuto Masamoto ◽  
Jeff Kershaw ◽  
Masakatsu Ureshi ◽  
Naosada Takizawa ◽  
Hirosuke Kobayashi ◽  
...  
Keyword(s):  
Time Course ◽  
Oxygen Demand ◽  
Excess Demand ◽  
Tissue Oxygen ◽  
Doppler Flowmetry ◽  
Demand And Supply ◽  
Brain Functions ◽  
Apparent Diffusion ◽  
Time Required ◽  
Stimulus Length

To investigate the dynamics of tissue oxygen demand and supply during brain functions, we simultaneously recorded Po2 and local cerebral blood flow (LCBF) with an oxygen microelectrode and laser Doppler flowmetry, respectively, in rat somatosensory cortex. Electrical hindlimb stimuli were applied for 1, 2, and 5 s to vary the duration of evoked cerebral metabolic rate of oxygen (CMRO2). The electrical stimulation induced a robust increase in Po2 (4–9 Torr at peak) after an increase in LCBF (14–26% at peak). A consistent lag of ∼1.2 s (0.6–2.3 s for individual animals) in the Po2 relative to LCBF was found, irrespective of stimulus length. It is argued that the lag in Po2 was predominantly caused by the time required for oxygen to diffuse through tissue. During brain functions, the supply of fresh oxygen further lagged because of the latency of LCBF onset (∼0.4 s). The results indicate that the tissue oxygen supports excess demand until the arrival of fresh oxygen. However, a large drop in Po2 was not observed, indicating that the evoked neural activity demands little extra oxygen or that the time course of excess demand is as slow as the increase in supply. Thus the dynamics of Po2 during brain functions predominantly depend on the time course of LCBF. Possible factors influencing the lag between demand and supply are discussed, including vascular spacing, reactivity of the vessels, and diffusivity of oxygen.

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