AN INVESTIGATION OF VELOPHARYNGEAL CLOSURE WITH LINEAR REGRESSION

Cleft lip and palate is a common birth defect in the United States. Children diagnosed with this abnormality face difficulties during feeding, hearing and speech. Surgical methods exist to repair the cleft lip and palate but often require subsequent surgeries as children are unable to gain full speech capabilities as they tend to develop hypernasal speech due to velopharyngeal inadequacy. Investigating velopharyngeal closure can help speech pathologists, surgeons and related professionals understand the effect of velopharyngeal anatomy on velopharyngeal function. In order to accomplish this, several studies have used two dimensional and three dimensional modeling to visualize the velum. Very few attempts have been made to track the velum and plot its movement against time. Image segmentation has been used widely for various purposes. However, its proficiency in tracking the velum is questionable at the moment. Two image segmentation methods, EdgeTrak and the Hidden Markov Model, are reviewed in this report. EdgeTrak, a software developed at the Video/Image Modeling and Synthesis Laboratory, has been proven to track the surface of a human tongue during speech production. An attempt was made to similarly track the velum during speech production using EdgeTrak but the results were disappointing. Also, synchronized audio mapping using the Hidden Markov Model was only partially successful. This report describes the challenges image segmentation faces with regards to tracking the velum.M.S

Vowel height and velum position in German: Insights from a real-time magnetic resonance imaging study

Velum position was analysed as a function of vowel height in German tense and lax vowels preceding a nasal or oral consonant. Findings from previous research suggest an interdependence between vowel height and the degree of velum lowering, with a higher velum during high vowels and a more lowered velum during low vowels. In the current study, data were presented from 33 native speakers of Standard German who were measured via non-invasive high quality real-time magnetic resonance imaging. The focus was on exploring the spatiotemporal extent of velum lowering in tense and lax /a, i, o, ø/, which was done by analysing velum movement trajectories over the course of VN and VC sequences in CVNV and CVCV sequences by means of functional principal component analysis. Analyses focused on the impact of the vowel category and vowel tenseness. Data indicated that not only the position of the velum was affected by these factors but also the timing of velum closure. Moreover, it is argued that the effect of vowel height was to be better interpreted in terms of the physiological constriction location of vowels, i.e., the specific tongue position rather than phonetic vowel height

Autologus fat grafting for mild to moderate velopharyngeal insufficiency: Our experience

The standard surgical treatment of velopharyngeal insufficiency (VPI) includes revision palatoplasty, posterior pharyngeal flap and sphincter pharyngoplasty. These procedures are not without complication and can also be challenging to the occasional cleft surgeon. The greatest complication is iatrogenic obstructive sleep apnoea particularly in high risk patients. With the introduction of posterior pharyngeal wall augmentation, a lesser and simpler surgical procedure, various materials have been used for this purpose with limited success and significant complication rates. Augmentation of the velo-pharynx with autologous fat has been practiced for decades. Autologous fat has multiple advantages compared to other biological and synthetic materials used for augmentation of the velopharynx. Autologous fat is readily available, has low donor site morbidity, does not migrate, injects easily and is non-allergenic. The outcome of fat grafting for VPI is good and stable long term, albeit unpredictable due to the resorption of fat. The procedure may therefore need to be repeated in order to achieve the desired results. The aim of this study is to evaluate and document the outcome of autologous fat grating for the treatment of mild to moderate VPI in children at the Red Cross War Memorial Children's Hospital (RCWMCH). A retrospective folder review was conducted on 9 consecutive patients who underwent velopharygeal fat grating for the treatment of mild to moderate VPI at the RCWMCH from 2010 to 2014. All the patients had had primary palatoplasty performed previously and subsequently developed VPI. Patients were assessed pre- and postoperatively by two cleft surgeons, and an experienced speech and language therapist with the aid of laterl view videofluoroscopy (VF). Pre-operative and post-operative perceptual speech assessments were performed by a dedicated speech and language therapist. Two senior cleft surgeons performed pre-and post-operative videofluoroscopy interpretations. Eleven fat grafting procedures were performed on 9 patients and an average of 5.64 ml (range 1 ml to 7 ml) of autologous fat was transferred to the velopharynx. The average age at the time of operation was 6.5 years (range 3 years to 14 years) with a follow-up period of 18 months (range 7 months to 34 months). Most of the patients (7 out of 9) showed improved speech following fat grafting. There were no complications related to the fat grafting procedure. This small study suggests that fat grafting is an effective, minimally invasive surgical alternative for the treatment of mild to moderate VPI and to our knowledge, is the first reported study from Africa

Data-Driven Critical Tract Variable Determination for European Portuguese

Technologies, such as real-time magnetic resonance (RT-MRI), can provide valuable information to evolve our understanding of the static and dynamic aspects of speech by contributing to the determination of which articulators are essential (critical) in producing specific sounds and how (gestures). While a visual analysis and comparison of imaging data or vocal tract profiles can already provide relevant findings, the sheer amount of available data demands and can strongly profit from unsupervised data-driven approaches. Recent work, in this regard, has asserted the possibility of determining critical articulators from RT-MRI data by considering a representation of vocal tract configurations based on landmarks placed on the tongue, lips, and velum, yielding meaningful results for European Portuguese (EP). Advancing this previous work to obtain a characterization of EP sounds grounded on Articulatory Phonology, important to explore critical gestures and advance, for example, articulatory speech synthesis, entails the consideration of a novel set of tract variables. To this end, this article explores critical variable determination considering a vocal tract representation aligned with Articulatory Phonology and the Task Dynamics framework. The overall results, obtained considering data for three EP speakers, show the applicability of this approach and are consistent with existing descriptions of EP sounds

Modeling of oropharyngeal articulatory adaptation to compensate for the acoustic effects of nasalization

Hypernasality is one of the most detrimental speech disturbances that lead to declines of speech intelligibility. Velopharyngeal inadequacy, which is associated with anatomic defects such as cleft palate or neuromuscular disorders that affect velopharygneal function, is the primary cause of hypernasality. A simulation study by Rong and Kuehn [J. Speech Lang. Hear. Res. 55(5), 1438–1448 (2012)] demonstrated that properly adjusted oropharyngeal articulation can reduce nasality for vowels synthesized with an articulatory model [Mermelstein, J. Acoust. Soc. Am. 53(4), 1070–1082 (1973)]. In this study, a speaker-adaptive articulatory model was developed to simulate speaker-customized oropharyngeal articulatory adaptation to compensate for the acoustic effects of nasalization on /a/, /i/, and /u/. The results demonstrated that (1) the oropharyngeal articulatory adaptation effectively counteracted the effects of nasalization on the second lowest formant frequency (F2) and partially compensated for the effects of nasalization on vowel space (e.g., shifting and constriction of vowel space) and (2) the articulatory adaptation strategies generated by the speaker-adaptive model might be more efficacious for counteracting the acoustic effects of nasalization compared to the adaptation strategies generated by the standard articulatory model in Rong and Kuehn. The findings of this study indicated the potential of using oropharyngeal articulatory adaptation as a means to correct maladaptive articulatory behaviors and to reduce nasalit