Relationships between muscle activity and velar position.

Five normal subjects were used to study the relations between muscle activity and velar position. The speech sample consisted of the sustained sounds /i/, /u/, /s/, nonnasal /a/, and nasalized /a/. Velar position was determined using lateral-view x-rays. Electromyographic activity was measured from hooked-wire electrodes intended to record from the levator veli palatini, palatoglossus, palatopharyngeus, and the superior pharyngeal constrictor muscles. A transnasal approach was used to insert electrodes intended for superior constrictor. It was found that 1) the level of levator activity was not directly related to velar position, 2) for a given velar position the level of levator activity was related to palatoglossus and/or palatopharyngeus activity in most cases, and 3) superior constrictor was active during all speech samples studied, but the level of activity was inconsistent both within and between subjects.