Automatic detection of hypernasal speech signals using nonlinear and entropy measurements

Automatic hypernasality detection in children with Cleft Lip and Palate is classically performed by means of acoustic analysis; however, recent findings indicate that nonlinear dynamics features could be useful for this task. In order to continue deepening in this issue, in this paper the discriminant capability of 4 different nonlinear dynamics features along with a set of 6 entropy measurements is studied. The whole set of features is optimized using an automatic feature selection technique based on principal component analysis. The decision about the presence or absence of hypernasality is made by employing a support vector machine. The system is tested over two databases, one considers the five Spanish vowels and the words /coco/ and /gato/, and the other one considers different German words. The performance of the system is presented in terms of accuracy, sensitivity, specificity and receiver operating curves. According to the results, the accuracy of system increases when nonlinear and entropy measures are combined.