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  • Research Article
  • Open Access

Analysis of Acoustic Features in Speakers with Cognitive Disorders and Speech Impairments

  • 1Email author,
  • 2,
  • 1,
  • 1 and
  • 1
EURASIP Journal on Advances in Signal Processing20092009:159234

  • Received: 31 October 2008
  • Accepted: 8 April 2009
  • Published:


This work presents the results in the analysis of the acoustic features (formants and the three suprasegmental features: tone, intensity and duration) of the vowel production in a group of 14 young speakers suffering different kinds of speech impairments due to physical and cognitive disorders. A corpus with unimpaired children's speech is used to determine the reference values for these features in speakers without any kind of speech impairment within the same domain of the impaired speakers; this is 57 isolated words. The signal processing to extract the formant and pitch values is based on a Linear Prediction Coefficients (LPCs) analysis of the segments considered as vowels in a Hidden Markov Model (HMM) based Viterbi forced alignment. Intensity and duration are also based in the outcome of the automated segmentation. As main conclusion of the work, it is shown that intelligibility of the vowel production is lowered in impaired speakers even when the vowel is perceived as correct by human labelers. The decrease in intelligibility is due to a 30% of increase in confusability in the formants map, a reduction of 50% in the discriminative power in energy between stressed and unstressed vowels and to a 50% increase of the standard deviation in the length of the vowels. On the other hand, impaired speakers keep good control of tone in the production of stressed and unstressed vowels.


  • Hide Markov Model
  • Discriminative Power
  • Full Article
  • Acoustic Feature
  • Linear Prediction

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Authors’ Affiliations

Communications Technology Group (GTC), Aragón Institute for Engineering Research (I3A), University of Zaragoza, 50018 Zaragoza, Spain
Department of General and Hispanic Linguistics, University of Zaragoza, 50009 Zaragoza, Spain


© Oscar Saz et al. 2009

This article is published under license to BioMed Central Ltd. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.