Effects of Listener Training and External Standard on the Reliability of Perceptual Judgment of Hypernasality

Background & Objectives: Perceptual judgment is the most valid technique for evaluating hypernasality. However, perceptual rating of hypernasality is subjective, variable, and highly prone to error. Therefore, it is necessary to investigate factors which affect the reliability of perceptual judgment with regard to hypernasality and to determine methods to control its subjectivity and variability. The purpose of the present study was to investigate whether listener training and external standards have positive effects on the reliability of perceptual judgment of hypernasality among inexperienced listeners. Methods: Twenty students majoring in speech pathology with no or limited experience evaluating the speech of patients with cleft palate participated in this study. The students evaluated speech samples of 28 children with cleft palate for degree of hypernasality in conditions with and without external standards before and after listener training. Inter-rater and intra-rater reliabilities and variability scores were obtained to determine the effect of training and external standards on perceptual judgments of hypernasality. Results: The results revealed that listener training and use of external standards helped to improve the reliability of perceptual judgment of hypernasality among inexperienced listeners. There were significant listener training, external standards, and interaction (external standards by training) effects in perceptual judgment of hypernasality. Discussion & Conclusion: The results suggest that listener training and use of external standards were effective in controlling subjectivity and variability of perceptual evaluation and in improving the reliability of perceptual judgment of hypernasality among inexperienced listeners.