Date of Degree
MA (Master of Arts)
Speech Pathology and Audiology
The purpose of this study was to further investigate the effects of articulation errors on perceptual ratings of nasality in speakers with repaired cleft palates, specifically looking at the effect of varying magnitudes of articulation errors and education on perception of nasality. A group of expert listeners, speech-language pathologists with significant clinical experience in the area of cleft palate and resonance disorders, first rated the articulatory proficiency and nasality of a number of utterances produced by children with repaired cleft palates, on separate 6-point scales. Their ratings were then used to categorize stimuli into a three-by-three matrix (mild, moderate, severe) using articulation deficit and nasality as the two dimensions of interest. Untrained listeners (undergraduates and graduate students in a speech-language pathology training program) were then asked to rate the level of nasality on a 1 (normal) to 6 (severe) scale. Listener group ratings were compared to each other and to the expert listeners. Significant differences (p=0.004) were found between the undergraduate and graduate students' ratings when compared to the expert listeners. Graduates, had lower inter- and intra-rater reliability compared to the undergraduates. For both undergraduates and graduates, the difference between their ratings and those of the expert listeners was significantly lower for stimuli with mild articulation errors compared to those with moderate (p<0.0001) and severe (p<0.0001) articulation errors. No significant differences (p=0.416) were found between difference scores for stimuli with moderate versus severe articulation errors. The results were interpreted to suggest that the magnitude, and perhaps type, of articulation errors affects perceived nasality, and that there are group differences between perceptual nasality ratings. These findings support the importance of articulation therapy for children with repaired cleft palates to both decrease articulation errors and decrease perceived nasality. Further, this study highlights the need for including awareness of this interaction in the training of speech-language pathologists in order for the “gold standard” of perceptual judgements to remain a valid and reliable measure.
Articulation errors and hypernasality, or nasal sounding speech, are common deficits seen in children with repaired cleft lip and/or palate. These two deficits affect intelligibility, but may also have an effect on each other. This study was designed to investigate how severity of articulation errors affects individual’s perceived nasality and the influence of training on the ability to separate the two when listening to speech. Eight stimuli with varying degrees of articulation errors and nasality were chosen by expert listeners for the study. During the study, undergraduate and graduate students rated the stimuli for perceptual nasality. The degree of articulation errors was found to affect the amount of nasality listeners perceived. Listeners attended to articulation errors when nasality was mild, to both when nasality was moderate, and to nasality when the nasality was severe. Further, undergraduates’ nasality ratings were more affected by articulation; however, graduate students’ ratings were more variable. These findings support the importance of articulation therapy for children with repaired cleft palates to both decrease articulation errors and decrease perceived nasality. Further, this study highlights the need for including awareness of this interaction in the training of speech-language pathologists in order for the “gold standard” of perceptual judgements to remain a valid and reliable measure.
Copyright 2016 Kristin Dattilo