![]() Measures capturing overall vowel space area (quadrilateral or triangular) have demonstrated less reliable discriminability. Kim et al., 2009), and multiple sclerosis ( Rosen et al., 2008). Similar results have been revealed for speakers with dysarthria secondary to Parkinson’s disease (PD), stroke ( Y.-J. Weismer and his colleagues ( Weismer et al., 2001 Weismer & Martin, 1992) found shallower F2 trajectories in male speakers with dysarthria secondary to amyotrophic lateral sclerosis (ALS) relative to age- and gender-matched healthy controls. Relative to healthy control speakers, movement of the second formant during vowel production, captured in a variety of contexts (e.g., consonant–vowel transitions, diphthongs, and monophthongs), was reduced for some dysarthric speakers ( Y.-J. Kim et al., 2009 Weismer et al., 2001 Weismer & Martin, 1992).Īlthough a variety of acoustic metrics have been derived to capture vowel production deficits in dysarthria, it remains unclear whether such metrics can be used to differentiate speakers with dysarthria from healthy controls. Kent, Weismer, Kent, & Rosenbeck, 1989 Y.-J. Other acoustic findings detailed are vowel formant pattern instability and reduced F2 slopes ( R. 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. The work discussed herein is the first of two articles investigating degraded vowel acoustics in dysarthria.
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