A comparative study of two acoustic measures of hypernasality

PURPOSE: This study aimed to compare 2 quantitative acoustic measures of nasality in children with cleft lip and palate (CLP) and healthy controls using formalized perceptual assessment as a guide. METHOD: Fifty participants (23 children with CLP and 27 age- and gender-matched healthy controls) aged between 4 and 12 years produced a variety of high and low vowels that allowed perceptual ratings of nasal resonance severity as well as acoustic analysis of spectral changes. Two objective measures of nasality were used: 1/3 octave spectra analysis and the voice low tone high tone ratio. Each respective technique has been evaluated in previous research, and their potential as an effective means of detecting changes in nasal resonance has been demonstrated. RESULTS: Only 1/3 octave spectra analysis differentiated between participants with hypernasal speech and those perceived to have normal nasal resonance. Significant differences were also observed between varying levels of perceived severity on vowels within nonnasalized phonemic environments (/pit/, /tip/). CONCLUSIONS: Perceptual judgment remains the primary means of evaluating levels of nasality in children with CLP. However, the development and validation of easy-to-use objective techniques remains an important goal for effective clinical and empirical practice.