Mind the Gap: How Velopharyngeal Gap Size Influences Consonant Accuracy

ObjectiveAssess if velopharyngeal gap size during speech is associated with consonant accuracy and whether hypernasality severity and compensatory misarticulation errors (CMAs) mediate this relationship.DesignCross-sectional.SettingMetropolitan hospital.ParticipantsEighty-one patients undergoing assessment for velopharyngeal insufficiency (VPI).Assessment(s)Each patient completed a preoperative magnetic resonance imaging protocol during sustained /i/ production and a perceptual speech evaluation. Velopharyngeal gap size was measured in millimeters. Hypernasality was rated using the Cleft Audit Protocol for Speech-Augmented-Americleft Modification. Percent consonants correct (PCC) and percent of CMAs used were derived from transcriptions of the American English sentence or phrase sample.Main Outcome Measure(s)A generalized structural equation model was used to examine whether velopharyngeal gap size is associated with PCC indirectly through hypernasality severity and CMA use.ResultsLarger velopharyngeal gap sizes were associated with more severe hypernasality (P < .001), greater hypernasality severity was associated with increased CMA use (P < .001), and greater CMA use was associated with lower PCC (P < .001). Velopharyngeal gap size was not directly associated with PCC (P = .400). However, the full indirect pathway from gap size to PCC through hypernasality severity and CMA use was significant (P = .001); gap size was significantly associated with PCC when accounting for both direct and indirect pathways combined (P = .005).ConclusionsThese findings suggest hypernasality severity is the key mediator between gap size and speech accuracy. Patients with more severe hypernasality may benefit from timely surgical remediation of VPI to increase overall consonant accuracy.