Effects of the Inhibition of Velopharyngeal Closure on the Velar Movement in Normal Subjects

• Published in: Journal of Japanese Cleft Palate Association Vol. 14; no. 1; pp. 44 - 70
• Main Author: HIRAHARA, Narihiro
• Format: Journal Article
• Language: Japanese
• Published: Japanese Cleft Palate Association 01.06.1989
• Subjects: electromyography (EMG); m. levator vela palatini; speech aid; velopharyngeal incompetence nasal tube; スピーチエイド; 口蓋帆挙筋; 筋電図; 経鼻チューブ; 鼻咽腔閉鎖不全
• ISSN: 0386-5185; 2186-5701
• DOI: 10.11224/cleftpalate1976.14.1_44

The effects of artifically induced velopharyngeal (V-P) incompetence on the palatal movement were examined in fifty-six normal subjects. Vinyl tubes of two sizes (6.5 mm and 5.5 mm diameter) were inserted into the V-P port via naris in order. Electromyographical (EMG) activates of m. levator veli palatini during phonation, blowing and swallowing were estimated and analysed. By altering aperture size at the end of the tube, the influences of intraoral air pressure on EMG were discussed. The strength (pressure) of V-P closure was also measured by use of original devices composed of balloon and microtip pressure transducer. Results were as follows: 1. EMG activities during phonation and blowing were markedly lowered by insertion of the tube to the V-P port. The lowering was greater in the larger tube. The values of EMG during plosives with larger tube were identical to those during nasals without tube (control). No change was observed during swallowing. 2. The influences of intraoral air pressure on EMG by altering aperture size were minimal during phonation. Meanwhile, EMG activity during blowing increased in accordance with air pressure. 3. The strength (pressure) of V-P closure showed correlation with EMG activity. The strength proved to become weak according to the width of remnant space caused by the balloon in the V-P port. 4. Mean values of sphincteric power measured at the V-P port with the balloon 6 mm in diameter were 110 g in plosives and fricatives,100-200 g in blowing and 220 g in swallowing. 5. These results imply that in the course of treatment on the operated cleft palate patient who need a speech aid, too large bulb must be strictly avoided because it might inhibit the activity. To activate the tightness of V-P closure, progressive reduction of bulb size may be beneficial.