ERIC Number: EJ1131873
Record Type: Journal
Publication Date: 2017-Feb
Abstractor: As Provided
Assessing Vowel Centralization in Dysarthria: A Comparison of Methods
Fletcher, Annalise R.; McAuliffe, Megan J.; Lansford, Kaitlin L.; Liss, Julie M.
Journal of Speech, Language, and Hearing Research, v60 n2 p341-354 Feb 2017
Purpose: The strength of the relationship between vowel centralization measures and perceptual ratings of dysarthria severity has varied considerably across reports. This article evaluates methods of acoustic-perceptual analysis to determine whether procedural changes can strengthen the association between these measures. Method: Sixty-one speakers (17 healthy individuals and 44 speakers with dysarthria) read a standard passage. To obtain acoustic data, 2 points of formant extraction (midpoint and articulatory point) and 2 frequency measures (Hz and Bark) were trialed. Both vowel space area and an adapted formant centralization ratio were calculated using first and second formants of speakers' corner vowels. Twenty-eight listeners rated speech samples using different prompts: one with a focus on intelligibility, the other on speech precision. Results: Perceptually, listener ratings of speech precision provided the best index of acoustic change. Acoustically, the combined use of an articulatory-based formant extraction point, Bark frequency units, and the formant centralization ratio was most effective in explaining perceptual ratings. This combination of procedures resulted in an increase of 17% to 27% explained variance between measures. Conclusions: The procedures researchers use to assess articulatory impairment can significantly alter the strength of relationship between acoustic and perceptual measures. Procedures that maximize this relationship are recommended.
Descriptors: Articulation Impairments, Neurological Impairments, Vowels, Comparative Analysis, Evaluation Methods, Acoustics, Listening, Auditory Perception
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Publication Type: Journal Articles; Reports - Research
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