Application of linear discriminant analysis to the nasometric assessment of resonance disorders: a pilot study

Objective : Nasalance scores have traditionally been used to assess hypernasality. However, resonance disorders are often complex, and hypernasality and nasal obstruction may co-occur in patients with cleft palate. In this study, normal speakers simulated different resonance disorders, and linear discriminant analysis was used to create a tentative diagnostic formula based on nasalance scores for nonnasal and nasal speech stimuli. Materials and Methods : Eleven female participants were recorded with the Nasometer 6450 while reading nonnasal and nasal speech stimuli. Nasalance measurements were taken of their normal resonance and their simulations of hyponasal, hypernasal, and mixed resonance. Results : A repeated-measures analysis of variance revealed a resonance condition-stimuli interaction effect (P < .001). A linear discriminant analysis of the participants' nasalance scores led to formulas correctly classifying 64.4% of the resonance conditions. When the hyponasal and mixed resonance conditions with obstruction of the less patent nostril were removed from the analysis, the resultant formulas correctly classified 88.6% of the resonance conditions. Conclusion : The simulations produced distinctive nasalance scores, enabling the creation of formulas that predicted resonance condition above chance level. The preliminary results demonstrate the potential of this approach for the diagnosis of resonance disorders.