Search

Aims: The aim of this work was to investigate the effects of commonly used orthodontic appliances on the magnetic resonance (MR) image quality of the craniofacial region, with special interest in the soft palate and velopharyngeal wall using real-time speech imaging sequences and anatomical imaging of the temporomandibular joints (TMJ) and pituitaries., Methods: Common orthodontic appliances were studied on 1.5 T scanner using standard spin and gradient echo sequences (based on the American Society for Testing and Materials standard test method) and sequences previously applied for high-resolution anatomical and dynamic real-time imaging during speech. Images were evaluated for the presence and size of artefacts., Results: Metallic orthodontic appliances had different effects on image quality. The most extensive individual effects were associated with the presence of stainless steel archwire, particularly if combined with stainless steel brackets and stainless steel molar bands. With those appliances, diagnostic quality of magnetic resonance imaging speech and palate images will be most likely severely degraded, or speech imaging and imaging of pituitaries and TMJ will be not possible. All non-metallic, non-metallic with Ni/Cr reinforcement or Ni/Ti alloys appliances were of little concern., Limitations: The results in the study are only valid at 1.5 T and for the sequences and devices used and cannot necessarily be extrapolated to all sequences and devices. Furthermore, both geometry and size of some appliances are subject dependent, and consequently, the effects on the image quality can vary between subjects. Therefore, the results presented in this article should be treated as a guide when assessing the risks of image quality degradation rather than an absolute evaluation of possible artefacts., Conclusions: Appliances manufactured from stainless steel cause extensive artefacts, which may render image non-diagnostic. The presence and type of orthodontic appliances should be always included in the patient's screening, so the risks of artefacts can be assessed prior to imaging. Although the risks to patients with fixed orthodontic appliances at 1.5 T MR scanners are low, their secure attachment should be confirmed prior to the examination., (© The Author 2015. Published by Oxford University Press on behalf of the European Orthodontic Society. All rights reserved. For permissions, please email: journals.permissions@oup.com.)

Purpose: This study predicted the effects of velopharyngeal (VP) anatomical parameters on VP function to provide a greater understanding of speech mechanics and aid in the treatment of speech disorders., Method: We created a computational model of the VP mechanism using dimensions obtained from magnetic resonance imaging measurements of 10 healthy adults. The model components included the levator veli palatini (LVP), the velum, and the posterior pharyngeal wall, and the simulations were based on material parameters from the literature. The outcome metrics were the VP closure force and LVP muscle activation required to achieve VP closure., Results: Our average model compared favorably with experimental data from the literature. Simulations of 1,000 random anatomies reflected the large variability in closure forces observed experimentally. VP distance had the greatest effect on both outcome metrics when considering the observed anatomic variability. Other anatomical parameters were ranked by their predicted influences on the outcome metrics., Conclusions: Our results support the implication that interventions for VP dysfunction that decrease anterior to posterior VP portal distance, increase velar length, and/or increase LVP cross-sectional area may be very effective. Future modeling studies will help to further our understanding of speech mechanics and optimize treatment of speech disorders.

An original three-dimensional (3D) linear articulatory model of the velum and nasopharyngeal wall has been developed from magnetic resonance imaging (MRI) and computed tomography images of a French subject sustaining a set of 46 articulations, covering his articulatory repertoire. The velum and nasopharyngeal wall are represented by generic surface triangular meshes fitted to the 3D contours extracted from MRI for each articulation. Two degrees of freedom were uncovered by principal component analysis: first, VL accounts for 83% of the velum variance, corresponding to an oblique vertical movement seemingly related to the levator veli palatini muscle; second, VS explains another 6% of the velum variance, controlling a mostly horizontal movement possibly related to the sphincter action of the superior pharyngeal constrictor. The nasopharyngeal wall is also controlled by VL for 47% of its variance. Electromagnetic articulographic data recorded on the velum fitted these parameters exactly, and may serve to recover dynamic velum 3D shapes. The main oral and nasopharyngeal area functions controlled by the articulatory model, complemented by the area functions derived from the complex geometry of each nasal passage extracted from coronal MRIs, were fed to an acoustic model and gave promising results about the influence of velum movements on the spectral characteristics of nasals.

Objective: To obtain detailed anatomic information on the levator veli palatini (LVP) muscle from magnetic resonance imaging (MRI). Quantitative measures of the configuration of the LVP muscle at rest and during speech activities were obtained., Design: Prospective study using MRI of adult subjects with normal velopharyngeal mechanisms to determine anatomic and physiologic parameters of the levator muscle. The levator veli palatini muscle was imaged at rest and during speech activities consisting of nasal and non-nasal sounds mixed with vowels, consonants, or both (e.g., /ansa, asna, amfa, afma/)., Participants: Ten normal healthy adults (five men, five women) between 21 and 53 years of age and free of oropharyngeal abnormalities., Main Outcome Measures: Two-dimensional spin echo static images and dynamic fast gradient echo images of the levator muscle in both the sagittal and oblique/coronal planes., Results: On average across female (F) and male (M) subjects: distance between LVP muscle origin points, 52.6 mm (F), 54.6 mm (M); angle of levator muscle origin at rest, 64.5 degrees (F), 60.4 degrees (M); length of the levator muscle at rest, 44.1 mm (F), 46.4 mm (M); width of levator muscle at lateral margin of velum, 5.5 mm (F), 6.6 mm (M). Both the levator muscle angle of origin and length became progressively smaller from rest, nasal consonants, low vowels, high vowels, and fricatives for both female and male subjects. Across all subjects, there was a 19% reduction in length of the LVP muscle from rest position to fricative production., Conclusions: MRI is an effective method of imaging and measuring the LVP muscle and related structures in living subjects. Understanding the normal tissue distribution and quantification of the LVP muscle provides important information for development of a functional biomechanical model of the velopharynx and for improved surgical treatment.

The purpose of this project was to assess the feasibility of imaging the velopharynx of adult volunteers during repetitive speech, using gated magnetic resonance imaging (MRI). Although a number of investigators have used conventional MRI in the study of the human vocal tract, the mismatch between the lengthy time necessary to acquire sufficiently detailed images and the rapidity of movement of the vocal tract during speech has forced investigators to acquire images either while the subject is at rest or during sustained utterances. The technique used here acquired a portion of each image during repetitive utterances, building the full image over multiple utterance cycles. The velopharyngeal portal was imaged on a 1.5-Tesla GE Signa LX 8.2 platform with gated fast spoiled gradient echo protocol. An external 1-Hertz trigger was fed to the cardiac gate. Subjects synchronized utterance of consonant-vowel syllables to a flashing light synchronized with the external trigger. Each acquisition of 30 phases per second at a single-slice location took 22 to 29 seconds. Four consonant-vowel syllables (/pa/, /ma/, /sa/, and /ka/) were evaluated. Subjects vocalized throughout the acquisition, beginning 5 to 6 seconds beforehand to establish a regular rhythm. Imaging of the velopharyngeal portal was performed for sagittal, velopharyngeal axial (aligned perpendicular to the "knee" of the velum), axial, and coronal planes. Volumes were obtained by sequential acquisition of six to 10 slices (each with 30 phases) in the axial or sagittal planes during repetition of the /pa/ syllable. Spatiotemporal volumes of the single-slice data were sectioned to provide time-motion images (analogous to M-mode echocardiograms). Three-dimensional dynamic volume renderings of palate motion were displayed interactively (Vortex; CieMed, Singapore). A method suitable for the collection and visualization of four-dimensional information regarding monosyllabic speech using gated MRI was developed. These techniques were applied to a population of adult volunteer subjects with no history of speech problems and two patients with a history of cleft lip and palate. The techniques allowed good real-time visualization of velopharyngeal anatomy during its entire range of motion and was also able to image pathology-specific anatomic differences in the subjects with cleft lip and cleft palate. These methods may be applicable to a wide spectrum of problems in speech physiology research and for clinical decision-making regarding surgery for speech and outcomes analysis.

Objective: The purpose of this study was to describe the pressure-flow characteristics of a large sample of speakers without cleft palate ranging in age from early childhood to young adulthood., Method: Speakers consisted of 223 children, teens, and adults without cleft palate categorized into five age groups: 6 through 8 years, 9 through 10, 11 through 12, 13 through 16, and 18 through 37 years. Speakers produced the syllables /mi/, /pi/, and /p/¿/, the word "hamper," and the sentence "Peep into the hamper." The pressure-flow method was used to determine oral air pressure, nasal airflow, and estimates of velopharyngeal (VP) orifice size associated with /ml and /p/ production. Descriptive statistics were computed for each age group and speech sample. Analysis of variance (ANOVA) procedures were used to determine the effects of age, sex, and production level (word versus sentence) on the aerodynamic variables., Results: ANOVA procedures indicated significant main effects (p < .01) of age on most of the aerodynamic variables during production of /m/ and /p/. No significant main effects or interactions involving sex were found for any variable. Regardless of age, approximately 95% to 99% of the speakers exhibited airtight VP closure during /p/ at syllable level, depending upon the selected nasal airflow criterion. ANOVA procedures also indicated significant main effects of production level (word versus sentence) on each of the aerodynamic variables during the /mp/ sequence. These effects appeared to be related to speaking rate., Conclusions: The study suggests that speakers without cleft palate exhibit essentially complete VP closure during production of oral pressure consonants in isolated syllables, and developmental aspects of speech aerodynamics be considered during pressure-flow testing.

A method to display dynamic aspects of vocal tract configuration during speech production by means of fast magnetic resonance imaging is presented. Data acquisition during repetitive movement relies on a stroboscopy-like procedure. The time resolution achieved is 120 images s-1 in a selected plane. As compared with other techniques of kinematic measurements of speech motor processes, this procedure allows for visualization of the temporal and spatial coordination of all relevant articulators, e.g. the entire tongue, the velum and the lower vocal tract. As an example, the method was applied to repetitions of stop consonant-vowel-nasal syllables.

The aims of this study are to determine visualization of normal phonation structures with the use of MR fast sequences and anatomical reference indices which can be used in evaluating upper resonator pathologies. A total of 12 normal subjects were studied, a 1 T system, a volumetric receiving head and neck coil and FLASH sequences for one sagittal and two coronal scans. Each subject was instructed to take a deep breath and then to produce the vowel sounds for the entire duration of the scan. The movement of the following anatomical structures were considered: lips, tongue, soft palate, pharynx and epiglottis. For each subject sagittal scans were used to measure the minimal palate tongue distance (p-t), the minimal anterio-posterior diameter of the mesopharynx (mp), and the epiglottis excursion angle (ep) with respect to the plane determined by the false vocal cords. Our results were compared with a diagrammed representation of tongue movements (vocal trapezium). This study underlines the validity of MR imaging techniques in the study of the phono-articulatory tract, because MR provided good detail of the phono-articulatory structures enabling an overall functional evaluation. MR would appear useful in evaluating defects in the velum and palate, in staging of oropharyngeal neoplasms and in surgical reconstructions of the tongue.

Objective: As a step toward better understanding of normal and abnormal velar control, a finite element model of the soft palate was developed., Design: A static two-dimensional midsagittal model of the velum was given physical dimensions to match that of a 10-year-old boy. Biomechanical properties of the tissues were inferred based on previous histologic studies. Velar movements were induced by the influence of three extrinisic velar muscles: the levator veli palatini, the palatoglossus, and the palatopharyngeus, which were simulated as external forces acting on the velar model., Results and Conclusions: Velopharyngeal opened and closed positions were simulated as well as a variety of intermediate steps between the two configurations. Velopharyngeal closure was also simulated in a manner appropriate for both high and low vowels. Future extensions of the model will incorporate the muscles as an intrinsic component of the model and will include a full time-dependent implementation, including inertial effects. Future studies will compare model predictions with experimental data from the laboratory, including both kinematic data and velopharyngeal closure forces.

Illustrative cases are presented showing a variety of interrelationships between the adenoids and the activity of the velopharyngeal valve in speech. The cases presented were selected from a group of 1000 patients referred because of suspected velopharyngeal diseases. When appropriate, complete velopharyngeal assessment was made including otolaryngological speech and hearing examination, polysomnography, nasendoscopy, multiview videofluoroscopy and cephalometry. New observations are described which further elucidate the mechanism by which the adenoids may change the mechanism of velopharyngeal valving and consequently speech patterns. In conclusion, procedures involving the adenoids and tonsils and surgical correction of velopharyngeal valve abnormalities to improve respiratory function must be performed in a manner which ensures preservation of normal speech activity. Similarly, surgical correction of velopharyngeal valve abnormalities to improve speech activity must preserve its respiratory function. The velopharyngeal valve and the adeno-tonsils must be considered together whenever diagnosis and a therapeutic intervention of either of them is considered. A clinical method for patient evaluation, patient management and the development of a rational therapeutic approach is presented.

Acoustic rhinometry as a means to detect changes in velar position was examined in this study. Videofluoroscopic recordings were made of two normal speakers maintaining velopharyngeal open and velopharyngeal closed (silent /f/) targets. Simultaneous acoustic rhinometric recordings were made during the production of each stimulus. Determinations of changes in velar positioning during the closed samples were made from fluoroscopic recordings and compared to nasal cavity-nasopharynx changes detected by rhinometry. The excellent agreement between the measures from the two procedures (less than 1 cm) indicates that acoustic rhinometry is capable of detecting changes in velar positioning during "silent" speech. Implications for assessment and future research are discussed.

Objective: To present illustrative cases showing various tonsillar influences on speech and to present a clinical method for patient evaluation establishing concepts of management and a rational therapeutic approach., Design: The cases were selected from a group of approximately 1000 patients referred to the clinic because of suspected palatal diseases. Complete velopharyngeal assessment was made, including otolaryngologic, speech, and hearing examinations, polysomnography, nasendoscopy, multiview videofluoroscopy, and cephalometry., Results: New observations further elucidate the intimate relation between the tonsils and the velopharyngeal valve. The potential influence of the tonsils on the velopharyngeal valve mechanism, in hindering or assisting speech, is described., Conclusions: In selected cases, the decision to perform tonsillectomy depends on its potential effect on speech. The combination of nasendoscopic and multiview videofluoroscopic studies of the mechanical properties of the tonsils during speech is required for patients who present with velopharyngeal insufficiency in whom tonsillar hypertrophy is found. These studies are also required in patients with palatal anomalies who are candidates for tonsillectomy.

Pressure-flow data are often used to provide information about the adequacy of velopharyngeal valving for speech. However, there is limited information available concerning simultaneous pressure-flow measurements for oral and nasal sound segments produced by normal speakers. This study provides normative pressure, flow, and velopharyngeal orifice area measurements for selected oral and nasal sound segments produced by 10 male and 10 female adult speakers. An aerodynamic categorization scheme of velopharyngeal function, including one typical category and three atypical categories (open, closed, and mixed) is proposed.

A two-part study was conducted to determine the accuracy of the pressure-flow method in estimating induced velopharyngeal orifice areas when the flow coefficient k was empirically determined. In Study 1, short tubes, 4.5 cm in length and with internal diameters of 3.2, 4.8, and 6.4 mm, were placed in a model of the vocal tract, and the associated flow coefficients were calculated. In Study 2, the 4.8-mm internal diameter tube was inserted into the nasopharynx of a normal adult subject to induce oronasal coupling during production of the syllable/pa/. Results for the human subject revealed that the error between the known and estimated orifice areas was approximately 7%. This finding indicates that the pressure-flow technique is accurate when the flow coefficient of the orifice is known. It is suggested that future research attempt to estimate flow coefficients associated with the geometry of the human velopharyngeal orifice in order to improve the accuracy of the pressure-flow technique.

Simultaneous cineradiographic and electromyographic analyses were made of the speech of three male and three female normal speaking adults. Each subject produced a series of symmetrical non-nasal CVC syllables embedded in a carrier phrase in a normal manner and also at increased rate and effort levels. A model of velar control was formulated and tested in relationship to changes in velar height resulting from forces provided by tongue positioning and contraction of levator veli palatini, palatoglossus, and palatopharyngeus muscles. Two patterns of levator activity were observed in the six subjects. Palatopharyngeus activity appeared to be important in producing adjustments in exact velar position when the velum was in a elevated state. Palatoglossus activity appeared to be related to elevation of the posterior portion of the tongue. The time differences between changes in muscle activity and velar positioning were determined. The results provide additional normative data regarding velar activity and serve to illustrate the need to view the velum as a complex mechanical system.

This study examined the accuracy of pressure-flow estimates of velopharyngeal (V-P) orifice size as applied to an analog model and two human subjects. Accuracy was assessed under differing conditions of degree of nasal resistance and type of instrumental interface. Known V-P orifice openings were introduced in the model through use of cover plates and in the humans through use of modified nasopharyngeal obturators. Nasal resistances were altered with perforated nasal plugs. Instrumental interfaces differed principally in the method used to detect nasal cavity pressure. Measures were applied to the hydrokinetic equation to estimate V-P area values. Data from the analog model and the human subjects were comparable in many respects. In low nasal resistance, area estimates were reasonably accurate regardless of the interface utilized. In high nasal resistance error typically increased, although not equally across interface types. Potential sources of error are identified and discussed.

The purpose of this experiment was to compare methods of measuring velar position during speech movements from lateral-view cineradiographic films. Specifically, correlations were calculated between measurements from a radiopaque marker sutured to the oral surface of the velum and three velar measurements that do not involve a radiopaque marker. As the correlations with the marker measurements were relatively high, it is concluded that experimenters may be free to choose any of the measurement procedures. The attachment of radiopaque markers to the velum does not appear necessary for obtaining a reliable and valid estimate of velar movements during speech.

Results of a small number of studies (Warren and DuBois, 1964; Lubker, 1969; Smith and Weinberg, 1980; Horii and Lang, 1981) have led to expression of divergent views concerning the accuracy of modeled velopharyngeal orifice area estimates obtained on the basis of hydrokinetic principles. In this work, the hydrokinetic equation (Warren and DuBois, 1964) was subjected to experimentation: (1) in which flow rates through a vocal tract model were not varied and (2) in which flow rates were varied to simulate pressure/flow events found during voiceless, stop consonant production. With consideration given to instrumental and procedural factors, results indicated that accurate estimates of modeled velopharyngeal orifice areas can be obtained during steady flow conditions and during alternating flow conditions when measurements are made at airflow peaks. Results were interpreted to provide strong support for clinical and research use of the hydrokinetic equation to predict velopharyngeal orifice areas during stop consonant production.

Very little is known about the developmental aspects of Passavant's ridge. Several studies have looked at the prevalence of Passavant's ridge in the cleft palate patient where palatopharyngeal insufficiency has been present from birth. No one has reported on the prevalence of Passavant's ridge in adults with acquired soft palatal defects that result in palatopharyngeal insufficiency. This information would add to our knowledge of the developmental aspects of formation of Passavant's ridge. In this study, 29 soft-palatectomy patients were examined with an oral panendoscope for presence of Passavant's ridge. Eighty-three percent of the patients had Passavant's ridge during speech; 17 percent did not. In the 83 percent that had the ridge, the intensity of movement varied and was equally distributed among minimal, moderate, and extreme movement.

A view of speech motor control is presented that is different from conventional coarticulation models. Rather than assuming that phonetic units specify targets for peripheral events, this view is based on holistic behavioral goals. The importance of discovering strategies that organize interactions among physiologic processes of the speech motor system is stressed. The concepts of motor flexibility and plasticity are developed. These motor control issues are used as the basis for discussing the relations among speech motor processes, critical minimum velopharyngeal port size, and speech adequacy in speakers with cleft palate. Different meanings of velopharyngeal incompetency are considered, and a potential misuse of the concept is explained. Finally, the developmental character of motor plasticity is discussed, and the implications of critical periods in speech motor learning are raised for children with cleft palate.

This investigation was undertaken to determine the effects of orthognathic surgery on speech. Forty adult females were studied preoperatively and either 6 or 12 months postoperatively. Three experienced speech and language pathologists performed narrow phonetic transcriptions of tape-recorded words and sentences produced by each of the forty patients. These judges also recorded their ratings of each patient's overall hypernasality, hyponasality, and articulation proficiency. In addition, objective assessments of velopharyngeal port area, nasal-oral acoustic coupling, and nasal resistance were obtained. The results suggest that nasal-oral acoustic coupling and nasal resistance are the only parameters significantly affected by orthognathic surgery.

Cephalometric x-rays were used to evaluate velar stretch in 20 normal adolescents during the production of /s/. Radiopaque markers were used so that the behaviors of both the anterior and posterior portions and the total velum cound be evaluated. Velar stretch was found in each of the subjects with the average stretch (15.19%) greater than the amount reported for 10-year-old subjects but less than the average stretch for adults. The correlation between amount of velar stretch and need ratio was not significant. The different stages of involution of adenoid tissue, which is characteristic of this age group, resulted in varying configurations of the naso-pharynx were postulated as one possible explanation for this unexpected finding. Normative data and clinical implications are presented.

A follow-up study was done on adult cleft patients with a total unilateral cleft with regard to the influence of the time of closure of the palate on speech. It was established that postponement of surgery of the palate from 3 to 6 years did not influence the ultimate result in respect of speech. One of the interesting findings was that in those patients who were operated on at the age of 3 there were more compensations than in those patients who were operated on at the age of 6. Pharyngoplasty did produce a satisfactory obturation between nasopharynx and the oral cavity in both age groups, but the ultimate quality of speech was clearly inferior to those patients who were not subjected to pharyngoplasty.

This study examined velar stretch in 20 young, normal adults during the production of /alpha/,/epsilon/, and /u/, and during blowing. Velar length was measured from cephalometric x-rays in two ways: (1) along the nasal surface of the velum and (2) along the velar midline. Results show no significant differences in velar stretch between males and females. Using nasal surface measures, there was significantly greater stretch for /u/ and for blowing than for /alpha/ and /epsilon/. For midline measures, the only differences which reached statistical significance were between blowing and /alpha/ or /epsilon/, which were not different from each other. Correlations between need ratio and percentage of stretch were significant as were correlations between percentage of velar stretch (nasal surface measure) and velar height. Comparisons of the two methods of measuring velar length are presented followed by a discussion concerning the significance of the findings.