LEVATOR-VELI-PALATINI MUSCLE-ACTIVITY IN RELATION TO INTRANASAL AIR-PRESSURE VARIATION

Continuous positive airway pressure (CPAP) therapy can be used to redu ce hypernasality by elevating the air pressure in the nasal cavities d uring speech. The purpose of this study was to determine whether incre ased intranasal air pressure loads the major muscle of velopharyngeal closure, the levator veli palatini. Nine subjects, four with cleft pal ate and five without cleft palate, were studied. Electromyographic act ivity was measured from the levator veli palatini muscle with several levels of air pressure delivered to the nasal cavities using a commerc ially available CPAP instrument. It was found that levator veli palati ni activity was significantly greater for the positive air pressure co nditions than for the atmospheric pressure conditions for both subject groups. This indicates that the levator veli palatini muscle acts aga inst the resistive load produced by the increased intranasal air press ure. The results support the use of CPAP therapy as a method of resist ance exercise for strengthening velopharyngeal closure muscles.