Methods for quantifying tongue shape and complexity using ultrasound imaging

Abstract

Quantification of tongue shape is potentially useful for indexing articulatory strategies arising from intervention, therapy and development. Tongue shape complexity is a parameter that can be used to reflect regional functional independence of the tongue musculature. This paper considers three different shape quantification methods – based on Procrustes analysis, curvature inflections, and Fourier coefficients – and uses a linear discriminant analysis to test how well each method is able to classify tongue shapes from different phonemes. Test data are taken from six native speakers of American English producing 15 phoneme types. Results classify tongue shapes accurately when combined across quantification methods. These methods hold promise for extending the use of ultrasound in clinical assessments of speech deficits.

Análise ultrassonográfica quantitativa do movimento da língua em 14 fonemas do Português Brasileiro

“…This finding corroborates with the international literature as in a specific study (10) that verified the success and appropriateness of the use of three types of analysis to quantify the form and the complexities of the tongue. The authors analyzed 15 phonemes of the English language produced by six typical adults through three indices based on Procrustes analysis ii , curvature inflections and Fourier coefficients.…”

“…ii Procustes analysis refers to a kind of statistical analysis used to analyze a distribution of a set of shapes (10) .…”

“…These studies contemplate both a qualitative and a quantitative description of patterns of speech production in adults (10,11) , in typical children (12,13) , and in different clinical groups, such as: hearing impaired individuals (14,15) , children with apraxia of speech (16,17) , glossectomized individuals (18,19) and individuals with tongue paresis (20) . Among the cited studies that aimed to analyze the typical production in adult and/or child speech (10)(11)(12)(13) , there is a limited number of individuals (varying from 6 to 10) using both qualitative and quantitative parameters to describe the tongue movement held in the production of different speech sounds (/p/; /t/; /k/; /f/; /s/; /∫/; /l/ e /r/). On the other hand, the studies that aimed to analyze speech production in different clinical groups mostly used ultrasound for therapeutic purposes, as a feedback instrument.…”

“…In the international literature, some ultrasonographic indices are described to differentiate the production of lingual phonemes of English, such as: MCI (Modified Curvature Index) (10) , Concavity, Anteriority, Asymmetry (18) , among others (11,13,20,21) . However, not all indices are sensitive to grasp the difference in typical production, not being used, until now, for clinical application.…”

A comparative study on the contour tracking algorithms in ultrasound tongue images with automatic re-initialization

“…Still, the scalability of the method is limited due to the necessity of extensive hand-scanning. For our future work, we would like to explore the potential application of the similarity index in several different aspects, which include tongue function region analysis (e.g., Lancia et al, 2015), quantifying the complexity of the tongue shape (e.g., Dawson et al, 2015), silent speech interface (e.g., Denby et al, 2010), etc.…”