Some acoustic evidence for vocal abuse in adult speakers with repaired cleft palate.

Acoustic evidence for vocal abuse in adult speakers with cleft palate and hypernasality has not been reported. This study was undertaken to determine if there was acoustic evidence of inappropriate vocal fold adduction during stop consonant production in this population. The results indicated that spectrograms of speakers without cleft palate and severe hypernasality exhibited acoustic characteristics different from spectrograms of speakers without cleft palate and speakers with cleft palate and mild hypernasality. Specifically, voiceless stop productions of severe hypernasal speakers resembled voiced stop productions. Their vocal folds were inappropriately adducted to provide a constriction inferior to the inadequately functioning velopharyngeal port to minimize the nasal air leak. The acoustic evidence supports the hypothesis that a cause of vocal abuse in the cleft palate population is due to compensatory laryngeal valving activities secondary to severe hypernasality.