Velopharyngeal movement patterns in patients alternating between oral and glottal articulation: a clinical and cineradiographical study. 
Eight patients who presented velopharyngeal incompetence and who spontaneously alternated between oral and glottal stop articulation were cineradiographically examined in lateral and frontal projections to compare their oral stops and glottal stop substitutions.  A cineradiographic frame-by-frame analysis of the movements of the velum and the lateral and posterior pharyngeal walls was performed.  During glottal stop substitutions and coarticulation involving glottal stops and oral lingual or bilabial stop gestures, all patients demonstrated either no velopharyngeal movement or impaired movement, mostly affecting the lateral pharyngeal walls.  In contrast, during oral stops, moderate-to-good velopharyngeal movements were produced.  Poor quality or absence of velopharyngeal movement associated with glottal stop substitutions may be misinterpreted as weakness or inability to perform motor activity.  Presurgical cineradiographic or fluoroscopic analysis of a patient's speech with regard to velopharyngeal movements should therefore be based on speech sequences free from glottal stop substitutions.  A careful speech analysis should also precede presurgical cineradiography.