The assessment of nasality with a nasometer and sound spectrography in patients with nasal polyposis.

With the development of computerized acoustic analysis systems, an objective measure of nasal speech has become readily available by means of a simple, noninvasive technique. In this study, we assessed the nasality in patients with multiple nasal polyposis before and after endoscopic sinus surgery. With the nasometer, we measured nasalance, which reflects the ratio of acoustic energy output of nasal sounds from the nasal and oral cavities, and the slope score of the nasogram curve. The nasalance scores of nasal sentences and the slope scores of the nasogram curves for all nasal consonants were significantly lower in patients with nasal polyposis than in healthy subjects. After surgery, however, the nasalance and slope scores increased significantly to the normal range. On the sound spectrographic analysis, the frequencies of the first nasal formant decreased slightly and the sound intensity increased slightly for all nasal consonants after surgery. However, no significant change was noticed in the frequencies of the second nasal formant. In conclusion, nasometric and sound spectrographic analyses are considered to be useful tools for objectively assessing the extent of nasality in patients with nasal airway obstruction.