Examination of the standard deviation of mean nasalance scores in subjects with cleft palate: Implications for clinical use

Objectives: To evaluate the standard deviation of the nasalance scores in patients having normal and abnormal nasal resonance and to determine its potential value for clinical use, Additionally, the mean nasalance scores were examined across varying degrees of hypernasality. Design: Prospective study design. Setting: Pediatric tertiary care hospital. Patients: One hundred and forty-eight subjects, ranging in age from 4;0 to 37;0 years, having repaired cleft lip and/or palate and normal resonance, inconsistent, mild, or moderate/severe hypernasality. Procedures: Oral-nasal acoustic measurements were made using the Nasometer, The standard deviation and mean nasalance scores were calculated for subjects reading three standard passages (Zoo Passage, Rainbow Passage, Nasal Sentences). Results: The major finding in this study showed that the standard deviation score cannot distinguish speakers beyond a gross normal and abnormal resonance diagnostic category, The values obtained could not be used to distinguish among the varying degrees of hypernasality, A secondary finding was that a mean nasalance score in the high 20s could be used to differentiate speakers with borderline velopharyngeal function from those who were non-nasal. Conclusions: In general, the standard deviation value serves little overall clinical utility; however, it may be of benefit in some specific clinical situations, In support of previous research, the mean nasalance score continues to be the best measure of nasalance, It should serve as a supplement to but not a substitute for clinical judgments.