Aerodynamic, acoustic, and perceptual measures of nasality following traumatic brain injury

Data were obtained from 31 subjects who had incurred a traumatic brain inju ry (TBI). Two expert listeners judged nasality using direct magnitude estim ation with a referent. They rated samples of the first sentence of the Rain bow Passage, played backwards, with all pauses removed. Sensitivity was goo d for nasalance, velopharyngeal airway resistance, and velopharyngeal orifi ce area, indicating that these measures would accurately identify an indivi dual as nasal. Specificity was reduced, and was adequate only for nasalance . The reduced specificity was due to a high number of false positives, i.e. perceived nasality in the absence of objective corroboration. Analysis of the false positives revealed that a slow speaking rate could mislead a list ener's perception of nasality. Overall, for individuals with dysarthria fol lowing TBI, the measure of nasalance may most accurately reflect listener p erception of nasality.