The Experts below are selected from a list of 285 Experts worldwide ranked by ideXlab platform
Mark S. Hedrick - One of the best experts on this subject based on the ideXlab platform.
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perceptual weighting of Relative Amplitude and formant transition cues in aided cv syllables
Journal of Speech Language and Hearing Research, 2001Co-Authors: Mark S. Hedrick, Mary Sue YoungerAbstract:The current study explored the changes in weighting of Relative Amplitude and formant transition cues that may be caused by a K-amp circuit. Twelve listeners with normal hearing and 3 listeners wit...
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effect of Relative Amplitude and formant transitions on perception of place of articulation by adult listeners with cochlear implants
Journal of Speech Language and Hearing Research, 1997Co-Authors: Mark S. Hedrick, Arlene Earley CarneyAbstract:Previous studies have shown that manipulation of a particular frequency region of the consonantal portion of a syllable Relative to the Amplitude of the same frequency region in an adjacent vowel influences the perception of place of articulation. This manipulation has been called the Relative Amplitude cue. Earlier studies have examined the effect of Relative Amplitude and formant transition manipulations upon labeling place of articulation for fricatives and stop consonants in listeners with normal hearing. The current study sought to determine if (a) the Relative Amplitude cue is used by adult listeners wearing a cochlear implant to label place of articulation, and (b) adult listeners wearing a cochlear implant integrated the Relative Amplitude and formant transition information differently than listeners with normal hearing. Sixteen listeners participated in the study, 12 with normal hearing and 4 postlingually deafened adults wearing the Nucleus 22 electrode Mini Speech Processor implant with the mul...
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Effect of Relative Amplitude manipulation on perception of voiceless fricatives by normal and impaired listeners
Journal of the Acoustical Society of America, 1997Co-Authors: Mark S. HedrickAbstract:In the present study, previous work on the Relative Amplitude and presentation level was extended to include the voiceless fricative /s/–/■/ contrast. Synthetic CV stimuli were used, in which format transitions, frication duration, and Relative Amplitude were manipulated. For the Relative Amplitude manipulation, the Amplitude of friction Relative to vowel onset in the F3 frequency range was varied across a 20‐dB range. Frication duration was varied from 140–50 ms. Stimuli were presented at 90 dB SPL. Eight listeners with normal hearing and three listeners with moderate sensorineural hearing loss participated in the experiment. Results showed that listeners with sensorineural hearing loss gave significantly more /s/ responses for lower Relative Amplitude values. Results from this study and previous studies [Hedrick et al., J. Acoust. Soc. Am. 98, 1292–1303 (1995); M. S. Hedrick and W. Jesteadt, J. Acoust. Soc. Am. 100, 3398–3407 (1996)] suggest that perception of acoustic cues for consonants by listeners w...
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effect of Relative Amplitude presentation level and vowel duration on perception of voiceless stop consonants by normal and hearing impaired listeners
Journal of the Acoustical Society of America, 1995Co-Authors: Mark S. Hedrick, Walt JesteadtAbstract:In the present study, previous work on the influence of Relative Amplitude and presentation level in listeners with normal hearing and those with sensorineural hearing loss is extended to include (1) a comparison of Relative Amplitude manipulation in the presence of neutral formant transitions versus manipulation of both formant transition and Relative Amplitude and (2) the additional variable of vowel duration. Synthetic CV stimuli were used, and the Amplitude of the burst Relative to the vowel in the F4–F5 frequency range was varied across a 20‐dB range. In experiment 1, some stimuli had neutral formant transition values and Relative Amplitude manipulations; other stimuli had both formant transition and Relative Amplitude manipulations. For stimuli in experiment 2, neutral formant transition values were used, Relative Amplitude was manipulated, and vowel duration ranged from 14 to 200 ms. Results from experiment showed no significant difference between subject groups when only Relative Amplitude information was manipulated, but significant differences when both Relative Amplitude and formant transition information was present. Results from experiment 2 indicated that vowel duration influenced the use of Relative Amplitude by listeners with normal hearing, but did not have this effect for listeners with sensorineural hearing loss. [Work supported by NIH.]
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Effect of Relative Amplitude, presentation level, and vowel duration on perception of voiceless stop consonants by normal and hearing-impaired listeners
Journal of the Acoustical Society of America, 1995Co-Authors: Mark S. Hedrick, Walt JesteadtAbstract:In the present study, previous work on the influence of Relative Amplitude and presentation level in listeners with normal hearing and those with sensorineural hearing loss is extended to include (1) a comparison of Relative Amplitude manipulation in the presence of neutral formant transitions versus manipulation of both formant transition and Relative Amplitude and (2) the additional variable of vowel duration. Synthetic CV stimuli were used, and the Amplitude of the burst Relative to the vowel in the F4–F5 frequency range was varied across a 20‐dB range. In experiment 1, some stimuli had neutral formant transition values and Relative Amplitude manipulations; other stimuli had both formant transition and Relative Amplitude manipulations. For stimuli in experiment 2, neutral formant transition values were used, Relative Amplitude was manipulated, and vowel duration ranged from 14 to 200 ms. Results from experiment showed no significant difference between subject groups when only Relative Amplitude informa...
Ralph N. Ohde - One of the best experts on this subject based on the ideXlab platform.
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The development of Relative Amplitude changes across acoustic discontinuities in nasal+vowel syllables
Journal of the Acoustical Society of America, 2007Co-Authors: Meredith A Oakey, Ralph N. OhdeAbstract:In adult productions of nasal+vowel syllables, Relative Amplitude changes occur in various frequency regions across acoustic discontinuities and provide important cues as to the place of articulation of nasal consonants. The purpose of this study was to investigate the development of Relative Amplitude changes in children as potential acoustic correlates to place of articulation. Four age groups of eight participants each (3, 5, 7, adult) served as speakers. Participants produced five productions each of CV syllables comprised of [m] and [n] in the context of four vowels ([i ae u ■]). These syllables were segmented into approximately 25 ms segments of the murmur and 25 ms segments of the vowel bordering the period of discontinuity. The Relative Amplitude changes in low‐ and high‐frequency ranges from the murmur to the vowel were determined using summed Amplitude information from fast Fourier transform (FFT) analyses. Previous research showed systematic differences in Relative Amplitude between [m] and [n] ...
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the development of Relative Amplitude changes across acoustic discontinuities in nasal vowel syllables
Journal of the Acoustical Society of America, 2007Co-Authors: Meredith A Oakey, Ralph N. OhdeAbstract:In adult productions of nasal+vowel syllables, Relative Amplitude changes occur in various frequency regions across acoustic discontinuities and provide important cues as to the place of articulation of nasal consonants. The purpose of this study was to investigate the development of Relative Amplitude changes in children as potential acoustic correlates to place of articulation. Four age groups of eight participants each (3, 5, 7, adult) served as speakers. Participants produced five productions each of CV syllables comprised of [m] and [n] in the context of four vowels ([i ae u ■]). These syllables were segmented into approximately 25 ms segments of the murmur and 25 ms segments of the vowel bordering the period of discontinuity. The Relative Amplitude changes in low‐ and high‐frequency ranges from the murmur to the vowel were determined using summed Amplitude information from fast Fourier transform (FFT) analyses. Previous research showed systematic differences in Relative Amplitude between [m] and [n] ...
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Effect of Relative Amplitude of frication on perception of place of articulation.
Journal of the Acoustical Society of America, 1991Co-Authors: Mark S. Hedrick, Ralph N. OhdeAbstract:The Amplitude of frication Relative to vowel onset Amplitude in the F3 and F5 formant frequency regions was manipulated for the synthetic fricative contrasts /s/–/∫/ and /s/–/θ/, respectively. The influence of this Relative Amplitude manipulation on listeners’ perception of place of articulation was tested by (1) varying the duration of frication from 30 to 140 ms, (2) pairing the frication noise with different vowels /i open aye u/, (3) placing formant transitions in conflict with Relative Amplitude, and (4) holding Relative Amplitude constant within a continuum while varying formant transitions and the Amplitudes of spectral regions where Relative Amplitude was not manipulated. To determine if listeners were using absolute spectral cues or Relative Amplitude comparisons between frication and vowel for fricative identification, the frication and vowel were separated by (1) presenting the frication in isolation, and (2) inserting a gap of silence between the frication and vowel. The results showed that re...
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effect of Relative Amplitude of frication on perception of place of articulation
Journal of the Acoustical Society of America, 1991Co-Authors: Mark S. Hedrick, Ralph N. OhdeAbstract:The Amplitude of frication Relative to vowel onset Amplitude in the F3 and F5 formant frequency regions was manipulated for the synthetic fricative contrasts /s/–/sh/ and /s/–/θ/, respectively. The efficacy of this Relative Amplitude manipulation on listeners’ perception of place of articulation was tested as a function of vowel contexts /i u ɑ /, frication durations of 30 to 140 ms, conflicting formant transitions, and variations in gross frication spectral shape and formant transitions appropriate to place of articulation. The results showed that the Relative Amplitude cue was invariantly perceived across vowel context and frication duration, overrode context‐dependent formant transition cues, and exerted primary influence on perception with variations in formant transitions and gross frication spectral shape appropriate to place of articulation. The results support a theory indicating that acoustic correlates of sound features exist, which are invariantly perceived. [Supported by NIH, DC00464.]
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Anchoring: A potential mechanism for processing Relative Amplitude of frication.
Journal of the Acoustical Society of America, 1991Co-Authors: Mark S. Hedrick, Ralph N. OhdeAbstract:The results from earlier research suggested that listeners use vowel Amplitude as a reference or anchor from which to determine the Amplitude level of a consonant for identification of place of articulation [Ohde and Stevens, J. Acoust. Soc. Am. 74, 706–714 (1983)]. The anchoring hypothesis was tested for a /s ɑ /–/sh ɑ / synthetic fricative contrast by inserting temporal gaps of silence between the fricative and vowel for several fricative durations. The findings revealed that temporal gaps affected perception of place of articulation, supporting the anchoring hypothesis. An interaction of frication duration with temporal gap duration suggested two stages of perceptual integration, with selection of the integration stage dependent on fricative duration. The results indicate that the Relative Amplitude property is a component of spectral prominence, which is comprised of a frication spectral peak and a fricative/vowel peak comparison [Stevens, J. Phon. 17, 3–45 (1989)]. [Supported by NIH, DC00464.]
Nikolaos Bonaros - One of the best experts on this subject based on the ideXlab platform.
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Relative Amplitude index a new tool for hemodynamic evaluation of periprosthetic regurgitation after transcatheter valve implantation
The Journal of Thoracic and Cardiovascular Surgery, 2014Co-Authors: A Heinz, Michael Decillia, Gudrun Feuchtner, Silvana Mueller, Thomas Bartel, Guy Friedrich, Michael Grimm, Ludwig C Mueller, Nikolaos BonarosAbstract:Objective The impact of paravalvular aortic regurgitation (PAR) on hemodynamic performance after transcatheter aortic valve implantation (TAVI) remains disputable. Common parameters such as the diastolic blood pressure or the blood pressure Amplitude do not provide reproducible results. The aim of our study was to evaluate the impact of PAR on hemodynamics and outcome using the Relative Amplitude index (RAI). Methods PAR was prospectively evaluated by echocardiography before discharge in 110 patients. The RAI was calculated according to the formula: RAI = [(Post-TAVI BP Amplitude)/(Post-TAVI SBP) − (Pre-TAVI BP Amplitude)/(Pre-TAVI SBP)] × 100%, where BP is blood pressure and SBP is systolic blood pressure. Correlations of increased RAI with perioperative outcome were investigated and factors influencing mortality were isolated. Results The incidence of moderate and severe PAR after TAVI was 9% and 1%, respectively. Diastolic pressure or post-TAVI Amplitude did not correlate to perioperative outcome. RAI increased from 2 when PAR was P = .006). A cut-off value of RAI ≥14 was associated with increased perioperative mortality (29 vs 5%; P = .013) and acute renal injury requiring dialysis (71 vs 18%; P = .001). RAI ≥14 was also associated with higher follow-up mortality at 1 year (57 vs 16%; P = .007). RAI ≥14 (odds ratio [OR], 3.390; 95% confidence interval [CI], 1.6-7.194; P = .00146), PAR ≥2+ (OR, 4.717; 95% CI, 1.828-12.195; P = .00135), and perioperative renal replacement therapy (OR, 12.820; 95% CI, 5.181-31.250; P = .00031) were found to be independent predictors of mortality at 1 year. Conclusions The RAI is a useful tool to predict perioperative and 1-year outcome in patients with PAR after TAVI.
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Relative Amplitude index a new tool for prediction of the impact of periprosthetic regurgitation on outcome after transcatheter aortic valve implantation
Thoracic and Cardiovascular Surgeon, 2013Co-Authors: Nikolaos Bonaros, A Heinz, Gudrun Feuchtner, Silvana Mueller, Thomas Bartel, Guy Friedrich, Michael Grimm, Fabian Plank, Thomas Schachner, Ludwig C MuellerAbstract:Objective: The impact of paravalvular leaks (PL) on hemodynamic performance after transcatheter valve implantation (TAVI) remains disputable. Using common hemodynamic parameters such as the diastolic blood pressure or the blood pressure Amplitude after the procedure has not provided reproducible results. The aim of our study was to systematically evaluate changes of hemodynamic parameters by using the Relative Amplitude index (RAI) and to assess its impact on outcome. Methods: PL were prospectively evaluated by echocardiography during TAVI and before discharge in 77 patients after TAVI. The RAI was retrospectively calculated according to the formula: RAI =((Post TAVI blood pressure Amplitude)/(Post TAVI systolic blood pressure)- (Pre TAVI blood pressure Amplitude)/(Pre TAVI systolic blood pressure)) x 100%. Univariate and multivariate analysis for risk factors for perioperative mortality was performed and an ROC analysis for RAI cut-off value was calculated. Results: The incidence of no PL mild, moderate and severe PL after TAVI was 20%, 62%, 15% and 3%, respectively. Evaluation by diastolic pressure or post TAVI Amplitude did not correlate to perioperative outcome. RAI increased from 0.7 ± 7% in the abscence of PL to 5.1 ± 8% in moderate to severe regurgitation (p = 0.027). A cutoff value of RAI = 13% was associated with increased perioperative mortality. Patients with a RAI> 13 had increased perioperative mortality (27 vs. 4%, p = 0.005), cardiac (9 vs. 0%, p < 0.001), and lung complications (27 vs. 4%, p < 0.001) and acute renal injury (20 vs. 8%, p = 0.002). Increased periprocedural RAI was associated with higher cardiac (33 vs. 15%, p = 0.011), renal (50 vs. 8%, p = 0.024) and lung comlications (7 vs. 0%, p = 0.005) at 1 year. RAI< 13 was an independent predictor of perioperative mortality (RR = 3.4, (CI = 1.8 – 5.0), p = 0.017). Conclusion: The RAI is useful non-invasive, easy-to-measure tool to predict the effect of paravalvular regurgitation on perioperative and 1-year outcome in patients with PL after TAVI.
Arlene Earley Carney - One of the best experts on this subject based on the ideXlab platform.
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effect of Relative Amplitude and formant transitions on perception of place of articulation by adult listeners with cochlear implants
Journal of Speech Language and Hearing Research, 1997Co-Authors: Mark S. Hedrick, Arlene Earley CarneyAbstract:Previous studies have shown that manipulation of a particular frequency region of the consonantal portion of a syllable Relative to the Amplitude of the same frequency region in an adjacent vowel influences the perception of place of articulation. This manipulation has been called the Relative Amplitude cue. Earlier studies have examined the effect of Relative Amplitude and formant transition manipulations upon labeling place of articulation for fricatives and stop consonants in listeners with normal hearing. The current study sought to determine if (a) the Relative Amplitude cue is used by adult listeners wearing a cochlear implant to label place of articulation, and (b) adult listeners wearing a cochlear implant integrated the Relative Amplitude and formant transition information differently than listeners with normal hearing. Sixteen listeners participated in the study, 12 with normal hearing and 4 postlingually deafened adults wearing the Nucleus 22 electrode Mini Speech Processor implant with the mul...
Shu Zhao - One of the best experts on this subject based on the ideXlab platform.
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Relative Amplitude preserved p p and p sv wave seismic sections
Journal of Geophysics and Engineering, 2004Co-Authors: Shu Zhao, Yanghua WangAbstract:In seismic wave propagation, the Amplitude decay along travel time comprises two components: the spherical divergence and the earth absorption effect in an inhomogeneous medium. In reservoir geophysics, both the P?P and P?SV wave seismic sections are required to be Relative-Amplitude preserved so that they can be used for comparative interpretation and analysis. Therefore, each of the following two processing steps, divergence correction and inverse Q filtering, applied to both seismic sections should be Relative-Amplitude preserved. In this paper, the spherical divergence corrections on the P?P and P?SV wave sections are expressed in unified formulae in which the formula for the P?SV wave section differs from that for the P?P wave section by a factor (1 + ?)?1, where ? is the ratio of P- to S-wave velocities, applicable to both the scale and power coefficients simultaneously. Divergence-corrected seismic sections are then used to estimate the earth Q models, which in turn are used to design inverse Q filters. Only when divergence correction and inverse Q filtering, both of which are Amplitude-related processing, applied to the P?P and P?SV wave sections are adequately accurate, the Amplitude information contained in these seismic sections can be reliably used for lithological analysis in reservoir geophysics.
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Relative Amplitude preserved P–P and P–SV wave seismic sections
Journal of Geophysics and Engineering, 2004Co-Authors: Shu Zhao, Yanghua WangAbstract:In seismic wave propagation, the Amplitude decay along travel time comprises two components: the spherical divergence and the earth absorption effect in an inhomogeneous medium. In reservoir geophysics, both the P?P and P?SV wave seismic sections are required to be Relative-Amplitude preserved so that they can be used for comparative interpretation and analysis. Therefore, each of the following two processing steps, divergence correction and inverse Q filtering, applied to both seismic sections should be Relative-Amplitude preserved. In this paper, the spherical divergence corrections on the P?P and P?SV wave sections are expressed in unified formulae in which the formula for the P?SV wave section differs from that for the P?P wave section by a factor (1 + ?)?1, where ? is the ratio of P- to S-wave velocities, applicable to both the scale and power coefficients simultaneously. Divergence-corrected seismic sections are then used to estimate the earth Q models, which in turn are used to design inverse Q filters. Only when divergence correction and inverse Q filtering, both of which are Amplitude-related processing, applied to the P?P and P?SV wave sections are adequately accurate, the Amplitude information contained in these seismic sections can be reliably used for lithological analysis in reservoir geophysics.
