Abstract
Background: Nasometry has supplemented perceptual assessments of nasality, using speech stimuli, which are devoid of nasal consonants. However, such speech stimuli are not representative of conversational speech. A weak relationship has been found in previous studies between perceptual ratings of hypernasality and nasalance scores for passages containing nasal consonants.
Aims: This study aimed to evaluate the relationship between perceptual assessment and acoustic measurements of nasality using controlled speech stimuli.
Methods & Procedure: A perceptual scale (the Temple Street Scale) describing nasality was devised for this study. Fifty children presenting with nasality were assessed using the Temple Street Scale and nasalance scores were obtained for specified speech samples using the Nasometer (Kay Elemetrics 6200.3). The relationship between the perceptual ratings and the nasometry results was evaluated using correlation analysis, test sensitivity, specificity, and overall efficiency.
Outcomes & Results: Correlation coefficients for perceptual ratings of nasality and nasalance scores ranged from 0.69 to 0.74. The sensitivity of the Nasometer ranged from 0.83 to 0.88; its specificity ranged from 0.78 to 0.95; while its overall efficiency was between 0.82 and 0.92.
Conclusions: The strong relationship between perceptual and acoustic assessments of nasality indicated that the Temple Street Scale and the Nasometer are both valid clinical tools for the evaluation of nasality when a carefully constructed speech sample is used. The need to use the Nasometer as a supplement to perceptual assessment is highlighted.