Kanji Nohara

Effect of placement of a speech appliance on levator veli palatini muscle activity during speech.

OBJECTIVE We have observed clinically that some speakers wearing a speech appliance for correction of velopharyngeal incompetence can blow with variable intensity without nasal air escape. This clinical finding suggests that tightness of velopharyngeal closure may be regulated in accordance with oral air pressure during blowing. The purposes of this electromyographic study were (1) to examine whether levator vell palatini muscle activity can be changed in relation to oral air pressure during blowing when the speech appliance is removed, (2) to clarify whether or not the change is related to the severity of velopharyngeal incompetence, and (3) to examine whether placement of a speech appliance can alter levator muscle activity into the equivalent of that of normal speakers during blowing. DESIGN Eight patients with repaired cleft palate, who routinely wear a palatal lift prosthesis (PLP) or a hybrid speech appliance of a pharyngeal bulb and palatal lift (bulb-PLP), served as subjects. Subjects were classified into one of two groups according to their speech appliance (PLP group and bulb-PLP group). Electromyography of the levator veli palatini muscle was recorded with a speech appliance in place and then with the speech appliance removed as the subject blew through a tube at three different effort levels. RESULTS In the removed condition, the change in levator activity in relation to oral air pressure was variable across subjects in the bulb-PLP group, whereas levator activity changed in relation to oral air pressure change for all subjects in the PLP group. However, levator activity changed in relation to oral air pressure with either speech appliance in place for all subjects irrespective of their speech appliance types. CONCLUSION The severity of velopharyngeal incompetence might be related in part to change in levator activity in association with oral air pressure. The effect of a speech appliance to correct velopharyngeal incompetence might consist not only of mechanical obturation of the velopharynx but also of alteration of velopharyngeal function to become similar to normal speakers. Moreover, it is likely that the velopharyngeal system could be well regulated so as to exhibit a consistent outcome of velopharyngeal function.

Regenerating Salivary Glands in the Microenvironment of Induced Pluripotent Stem Cells.

This report describes our initial attempt to regenerate salivary glands using induced pluripotent stem (iPS) cells in vivo and in vitro. Glandular tissues that were similar to the adult submandibular glands (SMGs) and sublingual glands could be partially produced by the transplantation of iPS cells into mouse salivary glands. However, the tumorigenicity of iPS cells has not been resolved yet. It is well known that stem cells affect their microenvironment, known as a stem cell niche. We focused on the niche and the interaction between iPS cells and salivary gland cells in our study on salivary gland regeneration. Coculture of embryonic SMG cells and iPS cells have better-developed epithelial structures and fewer undifferentiated specific markers than monoculture of embryonic SMG cells in vitro. These results suggest that iPS cells have a potential ability to accelerate differentiation for salivary gland development and regeneration.

Effects of the bolus volume on hyoid movements in normal individuals

The hyoid bone moves during swallowing due to contraction of suprahyoid muscles, which are critical components of normal swallowing function. It has been reported that the muscle force and shortening velocity decline gradually with age. Reduced hyoid velocities may delay the sealing of the laryngeal vestibule and opening of the cricopharyngeal muscle. We hypothesised that the hyoid velocity could be a factor influencing aspiration. This study evaluated effects of bolus volume changes on the hyoid distance and velocity in normal swallowing. The subjects were 21 healthy young adults. Lateral projection videofluorography was recorded while each subject swallowed 2·5, 5·0, 10 and 20 mL of liquid barium. We evaluated the maximum hyoid distance (Max d), anterior and superior distance (Max ad, Max sd). And, we evaluated the maximum velocity (Max v), anterior and superior velocity (Max av, Max sv). Two-way anova test revealed that Max d, Max ad and Max sd for different bolus volumes are not significantly different. But, two-way anova test showed statistically significant difference in Max v, Max av and Max sv among different bolus volume (P < 0·01). Tukeys test showed that there are significant differences in Max v between 2·5 and 20 mL, 5·0 and 20 mL, 10 and 20 mL, and 2·5 and 10 mL swallowing. And, Tukeys test showed significant differences in Max av and Max sv between 2·5 and 20 mL, 5·0 and 20 mL, and 10 and 20 mL swallowing. It is possible that a larger bolus volume requires greater maximum hyoid velocity. We plan to study hyoid velocity in elderly subjects and in those with dysphagia.

Change in palatoglossus muscle activity in relation to swallowing volume during the transition from the oral phase to the pharyngeal phase.

The purpose of this study was to examine whether the palatoglossus (PG) muscle is involved in the regulation of function during the transition from the oral to the pharyngeal phase. Seven normal adults participated in the study. Smoothed electromyography (EMG) signals of the PG muscle and levator veli palatini (LVP) muscle were collected. Each subject swallowed water at five different volumes: 12.5%, 25%, 50%, 100%, and 150% (or 200%) of his/her optimum swallowing volume. PG muscle waveform showed two patterns of activity: one of a single peak and the other of two peaks. There was no significant difference (p < 0.01) in the timing of emergence between the single peak and the second peak of the two-peak pattern. There were two patterns of PG muscle activity in response to a change in swallowing volume, i.e., one was a pattern in which the activity was correlated to the change in swallowing volume, the other was a pattern in which the activity was not changed but almost at the maximum activity level, irrespective of swallowing volume. We conclude that the PG muscle could be involved in the regulation of swallowing from the oral to the pharyngeal phase. The activity could be influenced by swallowing volume.

Evaluation of fatigability of the levator veli palatini muscle during continuous blowing using power spectra analysis.

Objective The purpose of this study was to compare the fatigability of the levator veli palatini (LVP) muscle during blowing in speakers who exhibit velopharyngeal incompetence with that from normal speakers by means of power spectra analysis. Design All subjects were instructed to blow into a tube for more than 10 seconds at maximum possible effort. The LVP muscle activity (electromyography) was sampled at 2 kHz for 10 seconds from the time when the oral air pressure during blowing was stabilized. These samples were subjected to Fast Fourier Transfer analysis with analytic windows of 0.5-second width. The electromyography mean power frequency slope with respect to time for each subject was estimated. Participants Three speakers with repaired cleft palate and three normal speakers were selected as subjects. Results The slopes of the regression lines for all three subjects with repaired cleft palate were negatively signed with statistical significance (t test, p < .01). The slopes for all of the normal speakers were negatively signed, but these were not statistically significant. Conclusion These results suggest that the LVP muscle of speakers with repaired cleft palate who exhibit varying degrees of velopharyngeal dysfunction may deteriorate more easily in comparison with the LVP muscle of normal speakers.

Change in Levator Veli Palatini Muscle Activity for Patients With Cleft Palate in Association With Placement of a Speech-Aid Prosthesis

OBJECTIVE The purpose of this study was to examine whether a speech-aid prosthesis normalizes the activity of the levator veli palatini muscle for patients with cleft palate who exhibit velopharyngeal incompetence. DESIGN Each subject was instructed to produce repetitions of /mu/, /u/, /pu/, /su/, and /tsu/ and to blow with maximum possible effort. Electromyographic (EMG) activity of the levator veli palatini muscle was recorded with and without a hybrid speech-aid prosthesis in place. PARTICIPANTS The participants were five patients with repaired cleft palate who were routinely wearing a hybrid speech-aid prosthesis. RESULTS With the prosthesis in place, the mean value of levator activity changed positively in relation to oral air-pressure change during blowing. Differences in levator activity in relation to speech samples were similar to those in normal speakers. With the prosthesis in place, levator activity for speech tasks was less than 50% of the maximum levator activity for all subjects. The findings were similar to those reported previously for normal speakers. CONCLUSION Placement of the prosthesis changed EMG activity levels of the levator veli palatini muscle to levels that are similar to normal speakers. It is possible that, with the increase in the differential levator activity between speech and a maximum force task, the velopharyngeal mechanism has a greater reserve capacity to maintain velopharyngeal closure compared with the no-prosthesis condition.

Erratum to: Videoendoscopic diagnosis for predicting the response to oral appliance therapy in severe obstructive sleep apnea

Purpose In treatment for obstructive sleep apnea (OSA), oral appliance (OA) therapy is indicated in patients with mild–moderate OSA. However, since patients with severe OSA in whom OA therapy was effective have also been reported, it may not be possible to determine indications for OA therapy based on the severity alone. The purpose of this study was to determine indications for OA therapy using endoscopy during wakefulness in patients with severe OSA.

Endoscopy evaluation to predict oral appliance outcomes in obstructive sleep apnoea

The objective of this study was to determine the utility of nasoendoscopy of the upper airway as a predictor of the efficacy of oral appliance treatment in obstructive sleep apnoea (OSA). A total of 61 consecutive patients with moderate-to-severe polysomnographically diagnosed OSA were recruited for this study. Using nasoendoscopy, we prospectively assessed the velopharynx and oro/hypopharynx in each patient while awake and in the supine position. We measured cross-sectional area (CSA), and anteroposterior and lateral diameters of the airway before and after mandibular advancement, and expressed the changes in dimensions as expansion ratios (after/before). We then compared the measurements of responders and nonresponders with oral appliance treatment. The expansion ratio (median (interquartile range)) for the CSA was greater in responders compared with nonresponders in the velopharynx (2.9 (2.3–5.0) versus 1.7 (1.5–1.9), p<0.001) and in the oro/hypopharynx (3.4 (2.5–5.6) versus 2.4 (1.8–3.7), p<0.05). Baseline apnoea–hypopnoea index and the CSA expansion ratio of the velopharynx were independent predictors of oral appliance treatment outcome based on a multivariate logistic regression analysis. The estimated area under the receiver operator characteristic curve was 0.87 and the cut-off value of the expansion ratio was 2.00. These results indicate that nasoendoscopy may have significant clinical utility in predicting the success of oral appliance treatment. A pronounced increase of the velopharynx with mandibular protrusion is a good predictor of oral appliance success http://ow.ly/V9lBU

Regulation of the Epithelial Adhesion Molecule CEACAM1 Is Important for Palate Formation

Cleft palate results from a mixture of genetic and environmental factors and occurs when the bilateral palatal shelves fail to fuse. The objective of this study was to search for new genes involved in mouse palate formation. Gene expression of murine embryonic palatal tissue was analyzed at various developmental stages before, during, and after palate fusion using GeneChip® microarrays. Ceacam1 was one of the highly up-regulated genes during palate formation, and this was confirmed by quantitative real-time PCR. Immunohistochemical staining showed that CEACAM1 was present in prefusion palatal epithelium and was degraded during fusion. To investigate the developmental role of CEACAM1, function-blocking antibody was added to embryonic mouse palate in organ culture. Palatal fusion was inhibited by this function-blocking antibody. To investigate the subsequent developmental role of CEACAM1, we characterized Ceacam1-deficient (Ceacam1 −/−) mice. Epithelial cells persisted abnormally at the midline of the embryonic palate even on day E16.0, and palatal fusion was delayed in Ceacam1 −/− mice. TGFβ3 expression, apoptosis, and cell proliferation in palatal epithelium were not affected in the palate of Ceacam1−/−mice. However, CEACAM1 expression was retained in the remaining MEE of TGFβ-deficient mice. These results suggest that CEACAM1 has roles in the initiation of palatal fusion via epithelial cell adhesion.

Prediction of Deterioration of Velopharyngeal Function Associated With Maxillary Advancement Using Electromyography of Levator Veli Palatini Muscle

Objective The purpose of the present study was to examine the possibility that postoperative velopharyngeal function following maxillary advancement could be predicted using preoperative electromyography of the levator veli palatini. Design Levator muscle electromyography was recorded preoperatively during speech and blowing. Levator activity was expressed as a percentage relative to the maximum value observed throughout the experiment. Postoperative velopharyngeal function was evaluated by means of perceptual judgment and nasoendoscopy. Participants The subjects were four patients with repaired cleft palates who underwent maxillary advancement, two by osteotomy and two by distraction osteogenesis. None of the subjects presented with preoperative hypernasality, and nasoendoscopy demonstrated complete velopharyngeal closure in all subjects prior to maxillary advancement. Results Preoperative levator activity for speech of two subjects was similar to that for normal speakers (<60% of total range), and postoperative nasality and nasoendoscopic findings revealed no detectible changes. For the other two subjects, levator activity for speech exceeded 60% of the total range, similar to that of speakers with velopharyngeal incompetence. These subjects showed increased hypernasality and deteriorated velopharyngeal closure following maxillary advancement. Conclusion The deterioration of velopharyngeal function associated with maxillary advancement was demonstrated for subjects whose levator activity was at higher levels during speech in comparison with maximal activity observed during blowing, regardless of the amount of maxillary advancement. Preoperative levator muscle electromyography could be a predictor in identifying patients at higher risk of postsurgical deterioration of velopharyngeal function.