1
|
Shadi MS, Hegazi MA, Ghandour HH, Othman NM, Khaled DM. Patterns of velopharyngeal closure during speech in individuals with normal habitual resonance: A nasoendoscopic analysis. Auris Nasus Larynx 2022; 49:995-1002. [DOI: 10.1016/j.anl.2022.04.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2021] [Revised: 03/13/2022] [Accepted: 04/04/2022] [Indexed: 10/18/2022]
|
2
|
Autologous Fat Grafting for the Treatment of Mild to Moderate Velopharyngeal Insufficiency. J Craniofac Surg 2019; 30:2441-2444. [DOI: 10.1097/scs.0000000000005337] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
|
3
|
Kobayashi Y, Kanamori D, Fujii N, Kataoka Y, Hirai E, Yoshioka S, Satoh K, Toyama H, Naito K, Matsuo K. Velopharyngeal closure analysis using four-dimensional computed tomography: a pilot study of healthy volunteers and adult patients with cleft palate. BMC Med Imaging 2019; 19:54. [PMID: 31286915 PMCID: PMC6613253 DOI: 10.1186/s12880-019-0350-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2019] [Accepted: 06/12/2019] [Indexed: 01/12/2023] Open
Abstract
Background Nasopharyngoscopy is a common method to evaluate velopharyngeal closure in patients with cleft palate. However, insertion of a fiberoptic nasopharyngoscope causes discomfort in patients. The aim of this study was to estimate the reliability of short-time exposure images obtained using 320-row area detector computed tomography (320-ADCT) as a novel evaluation method for the assessment of velopharyngeal function. Methods We evaluated five healthy adult volunteers and five postoperative adult patients with cleft palate. During a 3.3-s imaging exposure, the participants were asked to perform two tasks: nasal inspiration and subsequent oral expiration through a catheter into a water-filled cup. The movement of the velopharyngeal structures was recorded during each examination, and the presence of velopharyngeal insufficiency (VPI) and velopharyngeal closure (VPC) patterns were estimated. If VPI was detected, the cross-sectional area was also calculated. Cohen’s kappa and weighted kappa coefficients were used to evaluate the concordance of nasopharyngoscopy and 320-ADCT evaluation. Results Speech pathology evaluation did not reveal hypernasality in any study participant. Micro-VPI was detected by nasopharyngoscopy in one healthy volunteer and two patients. 320-ADCT detected micro-VPI in two more patients. The cross-sectional area of the VPI in these subjects ranged from 2.53 to 16.28 mm2. Nasopharyngoscopy and 320-ADCT were concordant in detecting VPI in eight participants (κ = 0.6) and in assessing VPC patterns in nine (κ = 0.82). Moreover, images obtained using 320-ADCT allowed for reduced dead angle and, thus, easy detection of micro-VPI and Passavant’s ridges. Conclusion Although the radiation exposure cannot be ignored, our novel evaluation method using 320-ADCT enables more detailed evaluation of VPC than nasopharyngoscopy. Future studies should investigate the relationship between 320-ADCT findings and speech pathology evaluations. Electronic supplementary material The online version of this article (10.1186/s12880-019-0350-4) contains supplementary material, which is available to authorized users.
Collapse
Affiliation(s)
- Yoshikazu Kobayashi
- Department of Dentistry and Oral-Maxillofacial Surgery, Fujita Health University, School of Medicine, 1-98, Dengakugakubo, Kutsukake, Toyoake, Aichi, 470-1192, Japan.
| | - Daisuke Kanamori
- Department of Dentistry, Nanakuri Memorial Hospital, Fujita Health University, 424-1, Oodoricho, Tsu, Mie, 514-1295, Japan
| | - Naoko Fujii
- Department of Radiology, Bantane Hospital, Fujita Health University, 3-6-10, Otobashi, Nakagawa-ku, Nagoya, Aichi, 454-8509, Japan
| | - Yumi Kataoka
- Department of Radiology, Fujita Health University Hospital, 1-98, Dengakugakubo, Kutsukake, Toyoake, Aichi, 470-1192, Japan
| | - Emiko Hirai
- Department of Otolaryngology, Fujita Health University, School of Medicine, 1-98, Dengakugakubo, Kutsukake, Toyoake, Aichi, 470-1192, Japan
| | - Satoshi Yoshioka
- Department of Otolaryngology, Fujita Health University, School of Medicine, 1-98, Dengakugakubo, Kutsukake, Toyoake, Aichi, 470-1192, Japan
| | - Koji Satoh
- Department of Dentistry and Oral-Maxillofacial Surgery, Fujita Health University, School of Medicine, 1-98, Dengakugakubo, Kutsukake, Toyoake, Aichi, 470-1192, Japan
| | - Hiroshi Toyama
- Department of Radiology, Fujita Health University, School of Medicine, 1-98, Dengakugakubo, Kutsukake, Toyoake, Aichi, 470-1192, Japan
| | - Kensei Naito
- Department of Otolaryngology, Fujita Health University, School of Medicine, 1-98, Dengakugakubo, Kutsukake, Toyoake, Aichi, 470-1192, Japan
| | - Koichiro Matsuo
- Department of Dentistry and Oral-Maxillofacial Surgery, Fujita Health University, School of Medicine, 1-98, Dengakugakubo, Kutsukake, Toyoake, Aichi, 470-1192, Japan
| |
Collapse
|
4
|
Sakamoto Y, Soga S, Jinzaki M, Yamada Y, Ogata H, Kishi K. Evaluation of velopharyngeal closure by 4D imaging using 320-detector-row computed tomography. J Plast Reconstr Aesthet Surg 2014; 68:479-84. [PMID: 25649217 DOI: 10.1016/j.bjps.2014.12.020] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2014] [Revised: 10/14/2014] [Accepted: 12/08/2014] [Indexed: 11/30/2022]
Abstract
OBJECTIVE Current imaging techniques for velopharyngeal closure (VPC) evaluation are two-dimensional, static, or distressing, thus necessitating multiple procedures to understand this three-dimensional and dynamic area. We validated the use of a novel four-dimensional (4D) computed tomography (CT) technique for the morphological and kinematic evaluation of VPC in cleft palate patients based on dynamic volume scanning with 320-detector-row CT. METHODS Five patients aged 4-10 years (40% males) with persistent velopharyngeal insufficiency post palatoplasty underwent conventional tests (cephalometry and video-nasal endoscopy) and 4D-CT. For each patient, complete multiplanar reconstruction, 4D airway CT, and 4D-CT endoscopy data for all scanning phases were compared with cephalometric and video-nasal endoscopy data. The movements of the velum and posterior pharyngeal walls were graded by each modality. RESULTS 4D airway CT revealed higher anatomical detail than cephalometry, additionally providing dynamic images. 4D-CT endoscopy and video-nasal endoscopy were in agreement for all patients regarding the patterns of VPC, with complete visualization of VPC in five versus one patient, respectively. 4D airway CT and cephalometry showed a discrepancy in one case, wherein grading by cephalometry was overestimated. 4D-CT was also useful in determining the width and length of a proposed pharyngeal flap. The examination time (mean ± standard deviation (SD), seconds), including patient preparation time, was 224 ± 73, 492 ± 145, and 718 ± 123 for cephalometric radiographs, CT, and video-nasal endoscopy, respectively. The mean estimated radiation dose during 4D-CT was 4.44 ± 1.64 mSv. CONCLUSIONS 4D-CT provides detailed morphological and kinematic analysis of VPC and may offer advantages over conventional procedures.
Collapse
Affiliation(s)
- Yoshiaki Sakamoto
- Department of Plastic and Reconstructive Surgery, Keio University School of Medicine, 35 Shinanomachi, Shinjuku-ward, Tokyo 160-8582, Japan
| | - Shigeyoshi Soga
- Department of Radiology, National Defense Medical College, 3-2 Namiki, Tokorozawa, Saitama 359-8513, Japan
| | - Masahiro Jinzaki
- Department of Diagnostic Radiology, Keio University School of Medicine, 35 Shinanomachi, Shinjuku-ward, Tokyo 160-8582, Japan.
| | - Yoshitake Yamada
- Department of Diagnostic Radiology, Keio University School of Medicine, 35 Shinanomachi, Shinjuku-ward, Tokyo 160-8582, Japan
| | - Hisao Ogata
- Department of Plastic and Reconstructive Surgery, Keio University School of Medicine, 35 Shinanomachi, Shinjuku-ward, Tokyo 160-8582, Japan
| | - Kazuo Kishi
- Department of Plastic and Reconstructive Surgery, Keio University School of Medicine, 35 Shinanomachi, Shinjuku-ward, Tokyo 160-8582, Japan
| |
Collapse
|
5
|
Bettens K, Wuyts FL, Van Lierde KM. Instrumental assessment of velopharyngeal function and resonance: a review. JOURNAL OF COMMUNICATION DISORDERS 2014; 52:170-183. [PMID: 24909583 DOI: 10.1016/j.jcomdis.2014.05.004] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/07/2014] [Revised: 04/14/2014] [Accepted: 05/16/2014] [Indexed: 06/03/2023]
Abstract
UNLABELLED The purpose of this literature review is to describe and discuss instrumental assessment techniques of the velopharyngeal function in order to diagnose velopharyngeal disorders and resonance characteristics. Both direct and indirect assessment techniques are addressed, in which successively nasopharyngoscopy, videofluoroscopy, magnetic resonance imaging (MRI), cephalometric radiographic analysis, computed tomography (CT), ultrasound, acoustic and aerodynamic measurements are considered. Despite the multiple instrumental assessments available to detect and define velopharyngeal dysfunction, the ideal technique is not yet accessible. Therefore, a combination of different quantitative parameters can possibly form a solution for a more reliable determination of resonance disorders. These multi-dimensional approaches will be described and discussed. The combination of quantitative measurement techniques and perceptual evaluation of nasality will probably remain necessary to provide sufficient information to make appropriate decisions concerning the diagnosis and treatment of resonance disorders. LEARNING OUTCOMES The reader will be able to describe and discuss currently available instrumental techniques to assess the velopharyngeal mechanism and its functioning in order to diagnose velopharyngeal disorders. Additionally, he will be able to explain the possible advantages of the combination of several types of complementary measurement techniques.
Collapse
Affiliation(s)
- Kim Bettens
- Department of Speech, Language and Hearing Sciences, Ghent University, Ghent, Belgium.
| | - Floris L Wuyts
- Department of Speech, Language and Hearing Sciences, Ghent University, Ghent, Belgium; Biomedical Physics, University of Antwerp, Antwerp, Belgium
| | | |
Collapse
|
6
|
Katoh C, Saitoh M, Tsuneyuki M, Tanimoto H, Hashikawa K, Tahara S, Otsuki N, Nibu KI. Blowing ratio as an evaluation tool for velopharyngeal function after oral and oropharyngeal cancer resection. Head Neck 2010; 32:1012-8. [PMID: 19953620 DOI: 10.1002/hed.21283] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Our objective was to evaluate the value of the blowing test to measure the speech and swallowing function after resection of oral or oropharyngeal cancer. METHODS Speech and swallowing functions of the patients after surgical resection of oral or oropharyngeal cancer were assessed by a speech intelligibility test, blowing time, questionnaires, and oropharyngeal pressures. Blowing time (pressure) ratio was determined by dividing blowing time (pressure) with open nose by blowing time (pressure) with closed nose. RESULTS Blowing time ratio had significant correlation with blowing pressure ratio (p = .014), score of speech intelligibility test (p = .0014), questionnaire for aspiration (p = .029), nasopharyngeal backflow (CC = 0.676, p = .032), amount of food to swallow (p = .037), and oropharyngeal pressure during swallowing (p = .024). CONCLUSION The present results demonstrated the value of blowing time ratio as a simple objective tool for speech and swallowing ability related to velopharyngeal function after resection of oral and oropharyngeal cancers.
Collapse
Affiliation(s)
- Chieri Katoh
- Department of Otolaryngology-Head and Neck Surgery, Kobe University Graduate School of Medicine, Kobe, Japan
| | | | | | | | | | | | | | | |
Collapse
|
7
|
Evaluation of dynamic magnetic resonance imaging in assessing velopharyngeal insufficiency during phonation. J Craniofac Surg 2008; 19:566-72. [PMID: 18520366 DOI: 10.1097/scs.0b013e31816ae746] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
Abstract
BACKGROUND Velopharyngeal insufficiency (VPI) expresses the structural and neuromuscular disorder of soft palate and pharyngeal walls inhibiting the normal functions of velopharyngeal (VP) sphincter mechanism. In this study, efficacy of dynamic magnetic resonance imaging in the diagnosis of VPI is investigated. MATERIALS AND METHODS A total of 32 cases, 16 controls and 16 cleft palates, were included in this study. T1 fast spin echo-weighted imaging during rest, dynamic investigations with True-fast imaging with steady-state precession sequence during /sss/ and /mmm/ phonations were performed. RESULTS During /sss/ phonation, complete closure was observed in the control group, whereas mean VP opening was 4.11 cm2 preoperatively and 0.21 cm2 postoperatively in the cleft palate group. In the postoperative period, only 3 patients did not have complete closure. In the second operations, performed 6 months later, only muscle repair was done. All 3 had complete closure. CONCLUSIONS In cleft palate cases with delayed diagnosis, appropriate application of muscle repair will be sufficient for anatomic repair of VPI without any extra procedures. In addition, dynamic magnetic resonance imaging is an objective, noninvasive, reliable, and effective modality that may be used in the diagnosis and treatment of VPI without any extra investigations.
Collapse
|
8
|
Schnitt DE, Agir H, David DJ. From Birth to Maturity: A Group of Patients Who Have Completed Their Protocol Management. Part I. Unilateral Cleft Lip and Palate. Plast Reconstr Surg 2004; 113:805-17. [PMID: 15108870 DOI: 10.1097/01.prs.0000105332.57124.89] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
The optimal management of the cleft lip and palate patient from birth to completion of treatment presents a formidable challenge to the plastic surgeon and the associated health care system. The multidisciplinary team approach for the management of these patients is widely accepted. However, a paucity of literature exists discussing specific protocol management, interventions, and the long-term outcomes of patients who have completed a strict treatment protocol with a consistent multidisciplinary team. The aim of this study was to present the details of the specific management protocol at the Australian Craniofacial Unit for cleft lip and palate patients and to present a group of patients who have completed this specific protocol and discuss the details of their long-term care. During a 28-year period from 1974 to 2002, the records of 337 patients treated for unilateral cleft lip and palate were evaluated. Of these 337 patients, 22 have completed the same specific protocol management. The same surgeon (David, the senior author) has been responsible for performing all operative interventions and for overseeing the care of each of the 22 patients, ensuring that the treatment protocol has been executed appropriately and without deviation. The interventions and outcomes were analyzed on the basis of speech, hearing, nasal airway, occlusion, psychosocial adjustment, and appearance. Because of the large volume of data and potential differences in outcomes, the authors' intention is to present this as part I of a four-part series beginning with unilateral cleft lip and palate. The results of isolated cleft palate, isolated cleft lip, and bilateral cleft lip and palate will be presented as parts II, III, and IV, respectively. Speech results were assessed as normal speech, mild abnormality, or severe abnormality by objective measures, and intervention for velopharyngeal insufficiency was noted. Seventeen patients were rated as having normal speech. Four patients were rated as having mild speech abnormality, one patient was rated as having severe speech abnormality, and seven patients required surgery for velopharyngeal insufficiency. Hearing results were measured objectively, and good hearing results were obtained in 18 cases. Five patients required tympanoplasty. All patients required alveolar bone grafting. The high Le Fort I osteotomy was performed in six cases. Bimaxillary surgery was performed in one case. Of all the patients assessed from birth to maturity, 13 required between three and five surgical interventions, and nine required six operations or more. Further details and photographs of preoperative and postoperative examples are provided.
Collapse
Affiliation(s)
- Drew E Schnitt
- Australian Craniofacial Unit, Women and Children's Hospital, Adelaide, Australia.
| | | | | |
Collapse
|
9
|
Poppelreuter S, Engelke W, Bruns T. Quantitative analysis of the velopharyngeal sphincter function during speech. Cleft Palate Craniofac J 2000; 37:157-65. [PMID: 10749056 DOI: 10.1597/1545-1569_2000_037_0157_qaotvs_2.3.co_2] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
OBJECTIVE This study reports a new concept for quantitative analysis of velopharyngeal function using electromagnetic articulography and simultaneous transoral video endoscopy. PARTICIPANTS The velopharyngeal closure mechanism was studied in 16 healthy German subjects during production of the vowel-consonant-vowel sequences /afa/ and /apa/. DESIGN Velar movements in the sagittal and vertical direction were measured by electromagnetic articulography (EMA) while video endoscopy was used for recording in the sagittal and transverse directions. MAIN OUTCOME MEASURE A transverse sagittal quotient (TSQ) was defined after the measurement of sagittal and transverse diameters of the velopharyngeal port (VPP) in the video-endoscopic pictures on the basis of a frame-by-frame analysis. RESULTS The sphincter morphology was objectively determined with the TSQ base value. A terminal sphincter deformation (TSD) for closure phases of articulatory movement was revealed by a qualitative shape analysis of the TSQ curves. CONCLUSIONS The assessment of the TSQ of velopharyngeal port diameters and the TSD in the terminal closure period lead to a new dynamic interpretation of velopharyngeal closure patterns.
Collapse
Affiliation(s)
- S Poppelreuter
- Department of Restorative Dentistry, Dental School, University of Goettingen, Germany
| | | | | |
Collapse
|
10
|
Poppelreuter S, Engelke W, Bruns T. Quantitative Analysis of the Velopharyngeal Sphincter Function During Speech. Cleft Palate Craniofac J 2000. [DOI: 10.1597/1545-1569(2000)037<0157:qaotvs>2.3.co;2] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
|
11
|
Finkelstein Y, Shapiro-Feinberg M, Talmi YP, Nachmani A, DeRowe A, Ophir D. Axial configuration of the velopharyngeal valve and its valving mechanism. Cleft Palate Craniofac J 1995; 32:299-305. [PMID: 7548102 DOI: 10.1597/1545-1569_1995_032_0299_acotvv_2.3.co_2] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
The variability of the normal velopharyngeal (VP) closure mechanism was studied by investigating VP anatomy in relation to its closure mechanism in 60 patients. The axial configuration of the VP isthmus, as observed in axial CT scans at rest, was found to be correlated with VP function in terms of its closure patterns in speech as observed by nasendoscopy. A flat VP isthmus was found to be closed mainly in the anteroposterior direction, forming the coronal closure pattern. A deep VP isthmus is closed by movement of the velum and medial movement of the lateral pharyngeal walls, forming the circular closure pattern. A flat VP isthmus occurs when the hamuli are posteriorly located and the muscular slings, therefore, open more posteriorly. We conclude that posterior insertion of the velar muscles on to the skull base results in a flatter, larger VP axial configuration, whereas an anterior insertion results in a VP axial configuration that is deeper and less flat. A flat VP isthmus contracts mainly in an anteroposterior direction, exhibiting a coronal closure pattern, while a deep or round VP isthmus contracts centripetally, exhibiting a circular closure pattern. Variability of the VP valving mechanism is of anatomic and not of functional origin.
Collapse
Affiliation(s)
- Y Finkelstein
- Department of Radiology, Meir Hospital, Kfar Saba, Israel
| | | | | | | | | | | |
Collapse
|
12
|
Boyne PJ, Christiansen EL, Thompson JR. ADVANCED IMAGING OF OSSEOUS MAXILLARY CLEFTS. Radiol Clin North Am 1993. [DOI: 10.1016/s0033-8389(22)02203-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
|
13
|
Henningsson G, Isberg A. Comparison between multiview videofluoroscopy and nasendoscopy of velopharyngeal movements. Cleft Palate Craniofac J 1991; 28:413-7; discussion 417-8. [PMID: 1742312 DOI: 10.1597/1545-1569_1991_028_0413_cbmvan_2.3.co_2] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
The videofluoroscopic and nasopharyngoscopic observations of velopharyngeal movements during speech were compared in 80 subjects with hypernasal speech. An endviewing flexible fiberoptic endoscope was used for nasopharyngoscopic examination. This failed to demonstrate movements of the lateral pharyngeal walls that were videofluoroscopically documented in one third of the patients. In the cases of disagreement, the angle of view was impaired because of the presence of adenoid tissue. The misinterpretation at nasopharyngoscopy was explained by an unfavorable observation position of the flexible scope and failure to pass it further into the pharynx. Conclusions are satisfactory that videofluoroscopy is an indispensable procedure for assessing velopharyngeal function.
Collapse
Affiliation(s)
- G Henningsson
- Department of Logopedics and Phoniatrics, Karolinska Institutet, Stockholm, Sweden
| | | |
Collapse
|
14
|
Yanagisawa E, Kmucha ST, Estill J. Role of the soft palate in laryngeal functions and selected voice qualities. Simultaneous velolaryngeal videoendoscopy. Ann Otol Rhinol Laryngol 1990; 99:18-28. [PMID: 2294830 DOI: 10.1177/000348949009900104] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The role of the soft palate in normal laryngeal functions and in the production of selected voice qualities was studied by a simultaneous velolaryngeal videoendoscopy technique. For this technique, the Olympus ENF-P flexible nasopharyngolaryngoscope was passed via one nostril to study the function of the larynx, while the Hopkins 70 degrees rhinoscopic telescope was passed via the other nostril to study the function of the soft palate and velopharyngeal closure. A Kay Elemetrics DSP Sona-Graph, model 5500, was used to analyze a complex vocal figure of five consecutive voice qualities, three of which were nasal, and two, oral. Simultaneous velolaryngeal videoendoscopy proved to be of great value for the understanding of the interaction of velar and laryngeal functions and for clarifying the mechanisms of nasal and twang qualities.
Collapse
Affiliation(s)
- E Yanagisawa
- Department of Surgery, Yale University School of Medicine, New Haven, Connecticut
| | | | | |
Collapse
|