Kent, Weismer, Kent, Vorperian, and Duffy (1999) as including centralization of formant frequencies, reduction of vowel space area (i.e., mean working vowel space), and abnormal formant frequencies for both high and front vowels. Kim, Weismer, Kent, & Duffy, 2009 Rosen, Goozee, & Murdoch, 2008 Turner, Tjaden, & Weismer, 1995 Watanabe, Arasaki, Nagata, & Shouji, 1994 Weismer, Jeng, Laures, Kent, & Kent, 2001 Weismer & Martin, 1992 Ziegler & von Cramon, 1983a, 1983b, 1986) and are summarized by K. The acoustic consequences of such vowel production deficits have been widely investigated (e.g., Y.-J. The articulatory mechanisms implicated in vowel production deficits in dysarthria include reduced excursion and velocity of lingual, lip, and jaw movements and aberrant movement timing (see Yunusova, Weismer, Westbury, & Lindstrom, 2008, for a brief review of the literature). In general, vowels produced by individuals with dysarthria are characterized by articulatory undershoot (i.e., failure of the produced vowel to reach canonical formant frequencies), resulting in compressed or reduced working vowel space (R.

In our companion article (see Lansford & Liss, 2014), we examine the correspondence between dysarthric vowel acoustics and vowel identification by healthy listeners.ĭistorted vowel production is a hallmark characteristic of dysarthria, irrespective of the underlying neurological condition ( Darley, Aronson, & Brown, 1969a, 1969b, 1975 Duffy, 2005). In the present article, we explore the extent to which acoustic metrics capturing vowel production deficits in dysarthria are capable of distinguishing healthy from dysarthric speech and among the different forms of dysarthria.

Such information is useful in the development of cognitive–perceptual models of intelligibility ( Lansford, Liss, Caviness, & Utianski, 2011). The larger goal of this project was to identify sensitive acoustic metrics that have the potential to predict listener performance. A comparison between patterns of response to measured degrees of vowel acoustic nasality and formant values demonstrate that vowel quality differences may play a more relevant role in word identification than type of nasality in a vowel.The work discussed herein is the first of two articles investigating degraded vowel acoustics in dysarthria. Preliminary results demonstrate that accuracy decreased for nasal and nasalized stimuli. To test this hypothesis, randomized stimuli containing the first syllable of words with oral, nasal and nasalized vowels were presented to BP listeners who had to identify the stimuli original word.

If so, vowel nasality should not be more informative for the perception of a word containing a nasal vowel than for a word containing a nasalized vowel, as nasality is attributed to coarticulation. It is argued that the nasal resonance may be the remains of a consonant that nasalizes the vowel, making nasal vowels simply coarticulatorily nasalized (e.g. Despite common belief that the language possesses contrastive nasal vowels, literature examination shows that nasal vowels may be followed by a nasal resonance, while nasalized vowels must be followed by a nasal consonant. This study explores the relationship between identification, degree of nasality and vowel quality in oral, nasal and nasalized vowels in Brazilian Portuguese.

Praat nasalized vowels