Although dysarthria is present in many neurologic diseases, its true incidence and prevalence is not fully known. Estimates and ranges vary based on the location of lesion, the nature and course of the underlying condition, and the assessment criteria used. Estimates of the prevalence of dysarthria associated with some common neurologic conditions are as follows:
- Stroke: It is estimated that 8%–60% of individuals with stroke present with dysarthria (Bogousslavsky, Melle, & Regli, 1988; Flowers, Silver, Fang, Rochon, & Martino, 2013; Jani & Gore, 2014; Kumral et al., 1988; Lawrence et al., 2001; Safaz, Kesikburun, Adigüzel, & Yilmaz, 2016; Teasell, Foley, Doherty, & Finestone, 2002; Vidović, Sinanović, Sabaskić, Haticić, & Brkić, 2011).
- Traumatic brain injury: Approximately 10%–65% of individuals with traumatic brain injury have dysarthria (Mitchell, Bowen, Tyson, Butterfint, & Conroy, 2017; Safaz, Alaca, Yasar, Tok, & Yilmaz, 2008; Sarno, 1980; Sarno, Buonaguro, & Levita, 1986; Yorkston, Honsinger, Mitsuda, & Hammen, 1989).
- Parkinson's disease: It is estimated that dysarthria affects approximately 70%–100% of individuals with Parkinson's disease (Hartelius & Svensson, 1994; Ho, Iansek, Marigliani, & Bradshaw, 1998; Logemann, Fisher, Boshes, & Blonsky, 1978; Müller et al., 2001).
- Multiple sclerosis: Between 25% and 50% of individuals with multiple sclerosis present with dysarthria at some point during the course of their disease (Darley, Brown, & Goldstein, 1972; Hartelius, Runmarker, & Andersen, 2000; Hartelius & Svensson, 1994; Yorkston, Beukelman, Strand, & Hakel, 2010).
- Amyotrophic lateral sclerosis: Dysarthria can be observed as an initial sign in up to 30% of individuals with amyotrophic lateral sclerosis, with almost all individuals developing dysarthria in later stages (Chen & Garrett, 2005; da Costa Franceschini & Mourão, 2015; Traynor et al., 2000).