David P Kuehn

University of Illinois, Urbana-Champaign, Urbana, Illinois, United States

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Publications (64)75.12 Total impact

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    ABSTRACT: Objective: The purpose of this study is to examine effects of sex, race, and craniometry among three distinct racial groups of adults with normal velopharyngeal anatomy and to determine whether craniofacial structures could be used to predict velopharyngeal structures. Methods: A total of 88 adults across three racial groups including white, black, and Asian (Japanese) participated. Magnetic resonance images were obtained using a high-resolution, three-dimensional anatomical scan. Measurements were obtained on the levator veli palatini muscle, velum, and craniofacial structures. Results: Head circumference was used as a covariate to control the effect of overall cranial size on the analyses. Palate height, linear cranial base, and face height and width vary based on sex, with men demonstrating larger values compared with women. Linear base values, cranial base angle, and face width vary significantly based on race, with Japanese subjects showing the smallest anterior to posterior measures and larger face-width values. Levator muscle measures, excluding angle measures, vary significantly (P < .0001) based on sex. There was no statistically significant difference (P > .05) among racial groups in the levator muscle measures. Velar length and thickness varied significantly based on race and sex. Conclusions: This is the first study to examine the interaction of race and sex on levator muscle morphology. In spite of the differences in velar dimensions, no significant differences were found in muscle size, specifically the levator veli palatini, which is contained within the velum.
    No preview · Article · Jan 2016 · The Cleft Palate-Craniofacial Journal

  • No preview · Conference Paper · Jan 2015
  • Youkyung Bae · David P Kuehn · Bradley P Sutton
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    ABSTRACT: Objectives: To examine muscle tissue distribution along the length of the velum in living individuals using magnetic resonance imaging (MRI). Design: Using the three-dimensional MRI data acquired from 10 normal white adults, two area measures including the muscular area and the total velar area were obtained from 10 oblique slices running perpendicular to velar length. A polynomial regression analysis was performed where the proportion of the muscular to the total velar area was regressed on the slice numbers running along the length of the velum. Results: The proportion of the muscular to total velar area increased from the anterior section of the velum, reaching a maximum (33.24%) in the midsection, and decreasing in the posterior section of the velum. A third-order (cubic) polynomial function that best illustrated the proportional data (R(2) = .47) was derived. Conclusions: The present study demonstrated that MRI is a viable tool to examine the muscle tissue distribution of the velum in living individuals. Although the overall pattern in the muscle tissue distribution of the healthy velum was similar to that reported in previous literature based on cadaver specimens, the participants in the present study appeared to have greater muscular proportion of the velum. The muscular proportion measure derived from the healthy living individuals can be used as an additional parameter accounting for sufficient intravelar muscle mass for future studies.
    No preview · Article · Sep 2014 · The Cleft Palate-Craniofacial Journal
  • Article: Erratum.
    Youkyung Bae · Jamie L Perry · David P Kuehn

    No preview · Article · Sep 2014
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    ABSTRACT: PurposeTo enable dynamic speech imaging with high spatiotemporal resolution and full-vocal-tract spatial coverage, leveraging recent advances in sparse sampling.Methods An imaging method is developed to enable high-speed dynamic speech imaging exploiting low-rank and sparsity of the dynamic images of articulatory motion during speech. The proposed method includes: (a) a novel data acquisition strategy that collects spiral navigators with high temporal frame rate and (b) an image reconstruction method that derives temporal subspaces from navigators and reconstructs high-resolution images from sparsely sampled data with joint low-rank and sparsity constraints.ResultsThe proposed method has been systematically evaluated and validated through several dynamic speech experiments. A nominal imaging speed of 102 frames per second (fps) was achieved for a single-slice imaging protocol with a spatial resolution of 2.2 × 2.2 × 6.5 mm3. An eight-slice imaging protocol covering the entire vocal tract achieved a nominal imaging speed of 12.8 fps with the identical spatial resolution. The effectiveness of the proposed method and its practical utility was also demonstrated in a phonetic investigation.Conclusion High spatiotemporal resolution with full-vocal-tract spatial coverage can be achieved for dynamic speech imaging experiments with low-rank and sparsity constraints. Magn Reson Med 73:1820-1832, 2015. © 2014 Wiley Periodicals, Inc.
    Full-text · Article · Jun 2014 · Magnetic Resonance in Medicine
  • Youkyung Bae · Jamie L Perry · David P Kuehn
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    ABSTRACT: To quantitatively examine the effects of body position on the positioning of the epiglottis, tongue, and velum at rest and during speech. Videofluoroscopic data were obtained from twelve healthy adults in the supine and upright positions at rest and during speech activities while the participants were producing 12 vowel-consonant-vowel (VNV) sequences. The effects of body position, target sounds, and adjacent sounds on structural positioning and vowel formant structure were investigated. Velar retro-positioning in the supine position was the most consistent pattern observed at rest. During speech, all structures, with varying degrees of adjustment, appeared to work against the gravitational pull, resulting in no significant narrowing in the oro- and naso-pharyngeal region while in the supine position. Minimal differences in the formant data between the body positions were also observed. Overall structural positioning was significantly dependent upon the target and adjacent sounds regardless of body position. The present study demonstrated that structural positioning in response to gravity varied across individuals based on the type of activities. With varying degrees of positional adjustment across different structures, fairly consistent articulatory positioning in the anterior-posterior dimension was maintained in different body positions during speech.
    No preview · Article · Oct 2013 · Journal of Speech Language and Hearing Research
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    ABSTRACT: Objective: Magnetic resonance imaging studies of the levator veli palatini muscle have used small numbers of subjects and have not consistently controlled for sex, race, or age. The purpose of this study was to conduct a structural assessment using a large homogeneous sample to examine the sex differences in the levator muscle morphology. Methods: Thirty white adult subjects (15 men and 15 women) were imaged using a 3 Tesla MRI system. A high-resolution SPACE (sampling perfection with application-optimized contrasts using different flip-angle evolution) sequence was used to acquire images of the velopharyngeal anatomy. Levator muscle measurements were obtained. Results: Men displayed significantly greater levator extravelar segment length (P = .003), levator intravelar segment muscle length (P < .001), greater distance between levator insertion points (P < .001), and greater angles of origin (P = .008) compared with women. There was no statistically significant variation between men and women in the distance between points of origin at the base of the skull. Conclusions: This study provides normative data to improve understanding of levator dysmorphology such as that in cleft palate muscle anatomy. Results of the study demonstrate significant differences between white men and women across several levator muscle measures. Variations in the relative size of the cranium or height of the individual were not proportionate to the variations observed in the levator muscle.
    No preview · Article · Jun 2013 · The Cleft Palate-Craniofacial Journal
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    ABSTRACT: Objective: Direct visualization of the velopharynx and, in particular, the levator muscle is particularly important in the assessment of velopharyngeal function and normal speech production. The purpose of this study is to demonstrate the development of a static and dynamic magnetic resonance imaging protocol for evaluation of velopharyngeal structures and function. Methods: A high-resolution, T2-weighted turbo-spin-echo three-dimensional anatomical scan (sampling perfection with application optimized contrasts using different flip angle evolution) was used to acquire a large field of view covering the velopharyngeal anatomy. Dynamic speech assessment was obtained using a fast-gradient echo, fast low-angle shot, multi-shot spiral technique to acquire 15.8 frames per second (FPS) of the sagittal and oblique coronal image planes. Results: Using a three-dimensional data set, as opposed to two-dimensional data, the full contour of the levator muscle can be appreciated. Dynamic images were obtained at 15.8 FPS in the sagittal and oblique coronal planes, enabling visualization of the movements of the velum, posterior pharyngeal wall, lateral pharyngeal walls, and levator muscle during speech. Conclusions: A three-dimensional magnetic resonance imaging sequence, such as that used in the present study, may provide better analyses and more precise measurements. A dynamic fast low-angle shot sequence allows for visualization of the levator muscle and the velum during speech at a high image rate. This protocol could have a significant impact in improving the process of visualizing pathology and promoting clinical treatment plans for individuals born with cleft lip and palate.
    No preview · Article · Apr 2013 · The Cleft Palate-Craniofacial Journal
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    David P Kuehn · Jerald B Moon
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    ABSTRACT: Abstract Musculus Uvulae.
    Preview · Article · Mar 2012 · The Cleft Palate-Craniofacial Journal
  • Panying Rong · David Kuehn
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    ABSTRACT: With the goal of using articulatory adjustments to reduce hypernasality, this study utilized an articulatory synthesis model (Childers, 2000) to simulate the adjustment of articulatory configurations with an open velopharynx to achieve the same acoustic goal as normal speech simulated with a closed velopharynx. To examine the effect of articulatory adjustment on perceived nasality, this study used an articulatory synthesis model (Childers, 2000) to synthesize 18 oral /i/ vowels, 18 nasal /i/ vowels, and 18 nasal /i/ vowels with computer-generated articulatory adjustments; these vowels were then presented to 7 listeners for perceptual ratings of nasality following the direct magnitude estimation method. Comparisons of nasality ratings of nasal vowels showed a significant reduction of perceived nasality after articulatory adjustment. Moreover, the acoustic features associated with nasal resonances were attenuated and the oral formant structures changed by nasalization were restored after articulatory adjustment, which confirmed findings in Rong and Kuehn (2010). Appropriate articulatory adjustments are able to reduce the nasality of synthetic nasal /i/ vowels by compensating for the acoustic deviations caused by excessive velopharyngeal opening. Such compensatory interarticulator coordination may have an application in using articulatory adjustments to reduce hypernasality in clinical speech therapies.
    No preview · Article · Mar 2012 · Journal of Speech Language and Hearing Research
  • P. Rong · R. Shosted · D. Kuehn
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    ABSTRACT: In this study, a speaker-adaptive articulatory model was constructed by fitting point-wise articulatory positions measured by electromagnetic articulography (EMA) to the vocal tract framework in [5] to customize a standard vocal tract model with speaker-dependent articulatory features. With the speakeradaptive articulatory model, the area functions of oral and nasal vowel pairs (/a/, /i/, /u/) were simulated. The differences of area functions between oral and nasal vowels were decomposed into orthogonal modes [10] to account for the primary oropharyngeal articulatory changes related to nasalization. The relationship between the principal articulatory modes and the lowest two formant frequencies (F1, F2) was examined to uncover the effect of oropharyngeal articulation on the acoustics of nasal vowels.
    No preview · Article · Jan 2012
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    ABSTRACT: To report the feasibility of using a 3-dimensional (3D) magnetic resonance imaging (MRI) protocol for examining velopharyngeal structures. Using collected 3D MRI data, the authors investigated the effect of sex on the midsagittal velopharyngeal structures and the levator veli palatini (levator) muscle configurations. Ten Caucasian healthy adults (5 women and 5 men) participated. A whole-head 3D MRI scan was obtained while participants were at rest in the supine position. Basic anatomic parameters of the velopharynx including midsagittal velopharyngeal structures and levator muscle configurations were compared between sexes. Detailed information on the 3D MRI protocol and data analysis method was introduced in the study. On the basis of the data, only the length of the levator muscle showed a statistically significant sex difference: Male participants had significantly longer levator muscles than those of female participants. The present study successfully demonstrated the use of 3D MRI in quantifying major velopharyngeal structures and provided additional data on the anatomic variations that exist in healthy adult individuals.
    No preview · Article · Nov 2011 · Journal of Speech Language and Hearing Research
  • Jamie L Perry · David P Kuehn · Bradley P Sutton
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    ABSTRACT: Abstract Background: No studies have reported the circumference and diameter of the levator veli palatini muscle at several points along its length and from both views (frontal and lateral). The purpose of this study was to provide quantitative data regarding the levator muscle morphology along the length of the muscle using magnetic resonance imaging and advanced 3D computer technology. Methods: Ten Caucasian male subjects participated in the study. Subjects were scanned using a Siemens 3 T Trio. Levator muscle measures were obtained using a 2D image plane. A three-dimensional model was used to measure the circumference and muscle diameter (in two directions) at six points along the length of the levator muscle. Results: Levator muscle length ranged from 41.67mm to 52.85mm across all subjects. Mean extravelar muscle length was 30.55mm (SD = 2.8mm) and 30.01mm (SD = 2.9mm) for right and left muscles. The mean circumference at the origin was 18.90mm (SD = 2.6mm). At the second point, the muscle circumference mean increased slightly (Mean = 22.40mm; SD = 4.9mm). The means for the remainder of the measures (points 3, 4, 5, and 6) were consistent showing little to no change. Conclusion: Circumference and diameter values were similar to those reported in previous literature. The muscle did not fan out at the point where the muscle bundle entered the velum, as it has been previously described. Instead, the muscle fans out near the midline insertion becoming sparser (smaller superior-to-inferior diameter). Key words: Magnetic resonance imaging, levator veli palatini muscle, muscle morphology.
    No preview · Article · Oct 2011 · The Cleft Palate-Craniofacial Journal
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    ABSTRACT: Surgical correction for submucous cleft palate is generally indicated in the presence of velopharyngeal inadequacy. Clinical assessment of velopharyngeal inadequacy requires that the child is able to produce a connected speech sample, which can yield a delay in treatment decisions that extends through a critical period of speech and language development. A perceptual speech assessment and intraoral examination are traditionally the most important methods of establishing a diagnosis of submucous cleft palate. The purpose of this case report is to demonstrate the use of magnetic resonance imaging as a diagnostic tool to provide early identification and an indication of surgical treatment for an individual born with a submucous cleft palate. The magnetic resonance images indicated a discontinuous levator veli palatini muscle sling arrangement with attachment of the muscle bundles onto the hard palate. Surgery was performed at 16 months and postsurgical speech evaluations demonstrated normal resonance and age-appropriate speech.
    No preview · Article · Jul 2011 · The Cleft Palate-Craniofacial Journal
  • Jamie L Perry · Youkyung Bae · David P Kuehn
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    ABSTRACT: The purpose of this study was to assess displacement of oropharyngeal structures, particularly the hyoid bone and velum, and variations in timing of the pharyngeal stage of swallowing in the upright versus the supine position. Twelve Caucasian adult subjects between 19 and 27 years of age participated. Subjects were recorded swallowing 7 cc of liquid barium in the upright and supine positions. The hyoid bone had a significantly greater amount of anterior displacement while in the supine position compared to that of the upright position (p < 0.01). While in the upright position, the velum comes to a fully elevated position at nearly the same time as the initiation of the pharyngeal swallow (within an average of 27 ms of each other), whereas in the supine position the velum continues to elevate on average 115 ms after the initiation of the pharyngeal swallow. Results indicated a significant difference (p < 0.05) in the amount of velar movement from rest to the fully elevated position between the upright and supine positions for female subjects. The results from the study demonstrate variations in hyoid displacement, velar movement, and bolus movement through the pharynx with respect to the two body positions and the subjects' gender.
    No preview · Article · Apr 2011 · Dysphagia
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    ABSTRACT: The current study was designed to obtain qualitative and quantitative information of the velopharyngeal mechanism and craniometric dimensions in infants born with a normal mechanism and in infants with an unrepaired cleft palate. Clinical magnetic resonance imaging data were obtained from the medical charts of 4 infants (2 with cleft lip and palate and 2 without) between the ages of 8 and 9 months. Craniometric measures and levator veli palatini muscle morphology were analyzed using visualization modeling software. Both raw measures and measures normalized by head circumference were examined. Patients 1 and 2 demonstrated normal velopharyngeal anatomy and a similar distance between levator muscle origins (38.9-40.7 mm), sagittal angles of origin (56-57 degrees), and levator muscle bundle lengths (28.4-30.7 mm). Patients with an unrepaired cleft palate displayed smaller oblique coronal angles of origins (58-62 degrees) compared with patients without cleft palate (62-67 degrees). Patients without cleft palate showed a steeper muscle (56-57 degrees) compared with patients without cleft palate (66-67 degrees). The basion-sella-nasion angle, hard palate length, and hard palate width measurements are related systematically to head circumference in this patient group. Results from the current study are in agreement with previous studies demonstrating variations across patients with cleft palate particularly in the muscle bundle lengths, distance between muscle origins, velar thickness, and velar length. Longitudinal studies are needed to determine how levator muscle and craniometric dimensions vary between those with and without cleft palate. A larger sample size is necessary to provide statistical analysis.
    No preview · Article · Mar 2011 · The Journal of craniofacial surgery
  • Seunghee Ha · David P Kuehn
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    ABSTRACT: Objective: The purposes of the study were to compare the temporal characteristics of nasalization between speakers with cleft palate with or without cleft lip and normal adult speakers and to investigate the relationship between acoustic temporal measures and perceived nasality. Methods: Fifteen speakers with cleft palate with or without cleft lip and 15 speakers without cleft palate aged 13 to 45 years participated in this study. Two listeners judged the degree of nasality in speakers with cleft palate with or without cleft lip. Two distinct acoustic energies derived from the mouth and nose were recorded simultaneously while speakers were producing the speech tasks /pimip/, /pamap/, and /pumup/. Absolute and proportional measures related to nasalization duration were obtained. Results: Speakers with cleft palate with or without cleft lip exhibited more extensive acoustic nasalization in the time domain than did speakers without cleft palate with or without cleft lip. Speakers without cleft palate with or without cleft lip showed larger nasalization-duration ratios in the high vowel contexts than in the low vowel context. Speakers with cleft palate with or without cleft lip did not exhibit distinct differences in nasalization-duration ratios among the vowel contexts. The acoustic measurements reflecting temporal patterns of oral-nasal acoustic impedance were related to the perception of hypernasality. Conclusions: These results suggest that the speakers with cleft palate with or without cleft lip showed longer duration of acoustic nasalization than speakers without cleft palate with or without cleft lip. Temporal characteristics of acoustic nasalization grew longer as the degree of perceived hypernasality increased. The positive correlation between temporal measures of acoustic nasalization and degree of perceived nasality suggests that temporal measures of nasalization would provide supplementary diagnostic information in relation to the degree of hypernasality.
    No preview · Article · Mar 2011 · The Cleft Palate-Craniofacial Journal
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    ABSTRACT: Objective : To examine the relationships between acoustic and physiologic aspects of the velopharyngeal mechanism during acoustically nasalized segments of speech in normal individuals by combining fast magnetic resonance imaging (MRI) with simultaneous speech recordings and subsequent acoustic analyses. Design : Ten normal Caucasian adult individuals participated in the study. Midsagittal dynamic magnetic resonance imaging (MRI) and simultaneous speech recordings were performed while participants were producing repetitions of two rate-controlled nonsense syllables including /zanaza/ and /zunuzu/. Acoustic features of nasalization represented as the peak amplitude and the bandwidth of the first resonant frequency (F1) were derived from speech at the rate of 30 sets per second. Physiologic information was based on velar and tongue positional changes measured from the dynamic MRI data, which were acquired at a rate of 21.4 images per second and resampled with a corresponding rate of 30 images per second. Each acoustic feature of nasalization was regressed on gender, vowel context, and velar and tongue positional variables. Results : Acoustic features of nasalization represented by F1 peak amplitude and bandwidth changes were significantly influenced by the vowel context surrounding the nasal consonant, velar elevated position, and tongue height at the tip. Conclusions : Fast MRI combined with acoustic analysis was successfully applied to the investigation of acoustic-physiologic relationships of the velopharyngeal mechanism with the type of speech samples employed in the present study. Future applications are feasible to examine how anatomic and physiologic deviations of the velopharyngeal mechanism would be acoustically manifested in individuals with velopharyngeal incompetence.
    No preview · Article · Dec 2010 · The Cleft Palate-Craniofacial Journal
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    ABSTRACT: To evaluate the impact of magnetic field inhomogeneity correction on achievable imaging speeds for magnetic resonance imaging (MRI) of articulating oropharyngeal structures during speech and to determine if sufficient acquisition speed is available for visualizing speech structures with real-time MRI. We designed a spiral fast low angle shot (FLASH) sequence that combines several acquisition techniques with an advanced image reconstruction approach that includes magnetic field inhomogeneity correction. A simulation study was performed to examine the interaction between imaging speed, image quality, number of spiral shots, and field inhomogeneity correction. Six volunteer subjects were scanned to demonstrate adequate visualization of articulating structures during simple speech samples. The simulation study confirmed that magnetic field inhomogeneity correction improves the available tradeoff between image quality and speed. Our optimized sequence co-acquires magnetic field maps for image correction and achieves a dynamic imaging rate of 21.4 frames per second, significantly faster than previous studies. Improved visualization of anatomical structures, such as the soft palate, was also seen from the field-corrected reconstructions in data acquired on volunteer subjects producing simple speech samples. Adequate temporal resolution of articulating oropharyngeal structures during speech can be obtained by combining outer volume suppression, multishot spiral imaging, and magnetic field corrected image reconstruction. Correcting for the large, dynamic magnetic field variation in the oropharyngeal cavity improves image quality and allows for higher temporal resolution.
    No preview · Article · Nov 2010 · Journal of Magnetic Resonance Imaging
  • Panying Rong · David P Kuehn
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    ABSTRACT: To study the acoustic characteristics of nasalized vowels, the effects of velopharyngeal opening and oral articulation are considered. Based on vocal tract area functions for one American English speaker, spectral evolutions for the nasalization of three English vowels /a/, /i/, and /u/ were studied by simulating transfer functions for vowels with only velar movement, and for different nasal consonant-vowel utterances, which include both velar and oral movements. Simulations indicate extra nasal spectral poles and zeros and oral formant shifts as a result of the velopharyngeal opening and oral movements, respectively. In this sense, if oral articulation is coordinated with velar movement in such a way that nasal acoustic features are prominently attenuated, corresponding compensatory articulation can be developed to reduce hypernasality. This may be realized by (1) adjusting the articulatory placement for isolated nasalized vowels or by (2) changing the relative timing of coarticulatory movements for dynamic speech. The results demonstrate the effect of oral articulation on the acoustics of nasalized vowels. This effect allows oral articulation to compensate for velopharyngeal dysfunction, which may involve a constellation of speech production disorders resulting from anomalous velopharyngeal closure and which is usually accompanied by hypernasality and nasal emission of air.
    No preview · Article · Apr 2010 · The Journal of the Acoustical Society of America