Yoshimi Inoko

Development of a sleep apnea event detection method using photoplethysmography

We studied the possibility of detection of sleep apnea or hypopnea events from photoplethysmography (PPG) wave variation patterns during sleep. In three patients with suspected sleep apnea syndrome, polysomnography (PSG) and the PPG wave were measured simultaneously during sleep. The characteristics of the PPG wave variation patterns in apnea or hypopnea events detected by PSG were investigated. It was found that pulse rate increases and pulse wave amplitude decreases during apnea or hypopnea events, and the respiratory component of heart rate variability has a tendency to decrease before the apnea or hypopnea events. Also, compared to hypopnea, the ratio of the pulse rate is higher, the reduction of the pulse amplitude is more significant, and the decrease of the degree of respiratory variation component in the apnea event is greater. We devised the apnea / hypopnea detection algorithm using these characteristics and evaluated its effectiveness.

Influence of oral appliances on craniocervical posture in obstructive sleep apnea–hypopnea syndrome patients

PURPOSE The existence of a relationship between head posture and mandibular function has been discussed by several authors. However, the relationship between head posture and the cervical spine in patients with obstructive sleep apnea-hypopnea syndrome (OSAHS) who are using oral appliances (OAs) remains unknown. The aim of this study was to evaluate the changes in the cervical spine associated with the use of OAs in patients with OSAHS. METHODS Fifteen patients (4 females and 11 males; mean age, 48 years) diagnosed with OSAHS were randomly selected. An OA was fabricated individually for each patient. Two lateral cephalometric radiographs were taken while the patient was sitting awake in an upright position. The first radiograph was taken in the intercuspal position and the second was taken while the subject was wearing the OA. Analyses based on the sella-nasion (SN) line were performed in the lateral cephalogram. Comparison of craniocervical angles in patients with and without the OA was performed using Wilcoxons signed-rank test. RESULTS Cephalometric analysis showed that the craniocervical angles (CVT-C2V and SN-C4) with OA were higher than those without OA (P<0.05). It seems that the OA caused a significant flexion of the cranium on the upper cervical spine. A significant increase in the craniocervical angle occurred in the fourth cervical segment. CONCLUSION The changes in forward flexion of the upper cervical spine found in this study imply that changes in the craniocervical relationship should be evaluated periodically after an OA has been inserted.

Influence of Posture and Respiration on the Morphology of Oropharynx -Analysis by Cephalometric Radiogram-

目的: 閉塞型睡眠時無呼吸症候群の歯科的治療に用いられる口腔内装置 (Oral appliance: OA) の効果に関する報告は, 多く認められる. しかし, 下顎前方位型装置 (Mandibular advancement device: MAD) の装着が口腔咽頭領域の形態に及ぼす影響について, 画像的に十分明らかにされていない. 本研究の目的は, 側方頭部X線規格写真 (セファログラム) 撮影時の体位および呼吸変化が, 口腔咽頭領域の形態に及ぼす影響を健常者について検討することである.方法: 被験者は, 自覚的, 他覚的にいびきを認めない健常者12名 (男性10名, 女性2名, 平均年齢27.3歳, 肥満度21.9kg/m2) とした. 被験条件は, 立位時の吸息と呼息および仰臥位時での吸息と呼息において, セファログラム撮影を行った. 撮影されたX線写真から得られた透写図上にて, 咽頭腔前後径とその面積, ならびに舌骨の位置の計測を行い, 体位と呼吸状態を2要因とする反復測定分散分析を用いて検討した.結果: 吸息時と呼息時の間に有意な差は認められなかった. しかし, 体位を立位から仰臥位に変化させると, 咽頭腔面積および口蓋垂後方の前後径と舌根部後方の前後径, 舌骨から下顎までの距離が有意に減少した.結論: 以上の結果から, 呼吸による影響は認められなかったが, 体位を立位から仰臥位に変化させることで口腔咽頭領域の形態に影響を及ぼすことが示された.