Yasuhiro Sasao

The effect of oral appliances that advanced the mandible forward and limited mouth opening in patients with obstructive sleep apnea: A systematic review and meta‐analysis of randomised controlled trials

Oral appliances (OAs) have demonstrated efficacy in treating obstructive sleep apnea (OSA), but many different OA devices are available. The Japanese Academy of Dental Sleep Medicine supported the use of OAs that advanced the mandible forward and limited mouth opening and suggested an evaluation of their effects in comparison with untreated or CPAP. A systematic search was undertaken in 16 April 2012. The outcome measures of interest were as follows: Apnea Hypopnea Index (AHI), lowest SpO2 , arousal index, Epworth Sleepiness Scale (ESS), the SF-36 Health Survey. We performed this meta-analysis using the Grading of Recommendations, Assessment, Development and Evaluation (GRADE) system. Five studies remained eligible after applying the exclusion criteria. Comparing OA and control appliance, OA significantly reduced the weighted mean difference (WMD) in both AHI and the arousal index (favouring OA, AHI: -7.05 events h(-1) ; 95% CI, -12.07 to -2.03; P = 0.006, arousal index: -6.95 events h(-1) ; 95% CI, -11.75 to -2.15; P = 0.005). OAs were significantly less effective at reducing the WMD in AHI and improving lowest SpO2 and SF-36 than CPAP, (favouring OA, AHI: 6.11 events h(-1) ; 95% CI, 3.24 to 8.98; P = 0.0001, lowest SpO2 : -2.52%; 95% CI, -4.81 to -0.23; P = 0.03, SF-36: -1.80; 95% CI, -3.17 to -042; P = 0.01). Apnea Hypopnea Index and arousal index were significantly improved by OA relative to the untreated disease. Apnea Hypopnea Index, lowest SpO2 and SF-36 were significantly better with CPAP than with OA. The results of this study suggested that OAs improve OSA compared with untreated. CPAP appears to be more effective in improving OSA than OAs.

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

Power Spectra Analysis of Levator Veli Palatini Muscle Electromyogram During Velopharyngeal Closure for Swallowing, Speech, and Blowing

The velopharynx closes during swallowing and pneumatic activities. Pneumatic closure, which is acquired, prevents expiratory air from passing into the nasal cavity, whereas during swallowing, velopharyngeal closure is achieved innately, preventing regurgitation into the nasal cavity. These findings suggest that velopharyngeal closure during swallowing is a different mechanism from that during pneumatic activity. The purpose of this study was to clarify activity differences of the levator veli palatini muscle during swallowing, speech, and blowing using power spectra analysis. Five normal adults served as subjects. Each subject was instructed to speak, blow, and swallow. Electromyograms of the levator muscle were recorded and the spectrum analyzed for each task to calculate the mean power frequency (MPF) of EMG signals. There was no significant difference in MPF between speech and blowing for all subjects. MPF was significantly greater during swallowing than during pneumatic activities for all subjects. The MPF value can reflect the composition of active motor units during muscle contraction. It was therefore indicated that the motor units of the levator muscle participating in contraction were different during swallowing and respiratory activities.

The efficacy of a lingual augmentation prosthesis for swallowing after a glossectomy: A clinical report

The excision of malignant tongue tumors often produces tongue defects that can cause dysphagia. A palatal augmentation prosthesis is frequently used to treat such dysphagia. This report describes a patient who received a palatal augmentation prosthesis after a glossectomy for malignant cancer of the tongue; however, no improvement was noted in swallowing function. A lingual augmentation prosthesis was then applied to the mandible, which resulted in improved swallowing function.

Effect of a Speech Aid Prosthesis on Reducing Muscle Fatigue

It has been reported that the levator veli palatini muscles of speakers with velopharyngeal incompetence tend to demonstrate muscle fatigue during speech. This study examined whether a speech aid prosthesis might reduce levator muscle fatigue in such speakers. Eight individuals with post-surgical cleft palates, and who wore a speech aid prosthesis, were studied. Each person was asked to pronounce the syllable [pu] more than 50 times. Mean power frequency (MPF) of one syllable was obtained from electromyographic data from the levator muscle. The MPF regression line was calculated during the course of syllable repetition. The absolute values of the slopes of the regression lines with the prosthesis were significantly smaller than those without the prosthesis. It was shown that the prosthesis reduced the decrease in MPF during speech. These results suggested that speech aid prostheses reduce levator muscle fatigue during speech in persons with velopharyngeal incompetence.

Videoendoscopic evaluation of food bolus preparation: A comparison between normal adult dentates and older adult dentates

Food bolus preparation plays an important role in swallowing food. The ability to carry out oral functions varies with age, and the same might be true of the ability to prepare food boluses. Previously developed methods for assessing food bolus preparation were not able to evaluate swallowed boluses; that is, the boluses were spat out before they were swallowed. The aim of the present study was to evaluate food bolus preparation in older adults using videoendoscopy, and to compare the food bolus preparation abilities of older adults and younger healthy adults.