Acoustic and Perceptual Cues to Contrastive Stress in Dysarthria Purpose: In this study, the authors sought to understand acoustic and perceptual cues to contrastive stress in speakers with dysarthria (DYS) and healthy controls (HC). Method: The production experiment examined the ability of 12 DYS (9 male, 3 female; M = 39 years of age) and 12 age- and gender-matched HC (9 male, 3 female; M = 37.5 years of age) to signal contrastive stress within short sentences. Acoustic changes in fundamental frequency (F0), intensity, and duration were studied. The perceptual experiment explored whether 48 unfamiliar listeners (24 male, 24 female; M = 23.4 years of age) could identify the intended stress location in DYS and HC productions. Results: Although both speaker groups used all 3 prosodic cues, DYS relied more heavily on duration. Despite reduced F0 and intensity variation within DYS utterances, listeners were highly accurate at identifying both DYS (> 93%) and HC (> 97%) productions. Acoustic predictors of listener accuracy included heightened prosodic cues on stressed words along with marked decreases in these variables for neighboring nonstressed words. Conclusions: Speakers signaled contrastive stress using relative changes in one or more prosodic cue. Although individual speakers employed different cue combinations, listeners were highly adept at discerning the intended stress location. The communicative potential of prosody in speakers with congenital dysarthria is discussed. KEY WORDS: prosody, dysarthria, acoustics, listener perception, contrastive stress P rosody serves various grammatical, semantic, social, and psycho- logical roles. Healthy speakers employ prosody to convey a multi- tude of functions, including signaling questions versus statements, conveying contrastive meanings, and expressing emotions and attitudi- nal states. Prosody also plays a role in marking lexical boundaries (Liss, Spitzer, Caviness, Adler, & Edwards, 1998) and in sentence disambigu- ation (Schafer, Speer, Warren, & White, 2000), thereby aiding in listener comprehension. The acoustic cues commonly associated with prosody in- clude fundamental frequency (F0), intensity, and duration (cf. Bolinger, 1961, 1989; Lieberman, 1967). In adverse listening conditions, these same cues are further enhanced to optimize communicative success (Lombard, 1911; Summers, Pisoni, Bernacki, Pedlow, & Stokes, 1988). Thus, prosody is a multifaceted aspect of the speech signal on which speakers and lis- teners must rely to accurately transfer information. Prosodic control in dysarthria has typically been characterized in terms of its deviations from nonimpaired speech, with the focus on reduced precision and flexibility of the dysarthric vocal apparatus (Canter, 1963; Darley, Aronson, & Brown, 1969, 1975; Hardy, 1983; Le Dorze, Oulette, & Ryalls, 1994; Wit, Maassen, Gabreels, & Thoonen, 1993). F0 range and its modulation within that range, however, are separate issues (Abberton, Rupal Patel Pamela Campellone Northeastern University, Boston, MA Journal of Speech, Language, and Hearing Research • Vol. 52 • 206–222 • February 2009 • D American Speech-Language-Hearing Association 1092-4388/09/5201-0206 206