Impairments of speech fluency in Lewy body spectrum disorder

► We examined speech fluency in patients with Lewy body spectrum disorder (LBSD). ► LBSD patients showed reduced overall speech rate and long silences between sentences. ► Articulation and grammar were impaired primarily in LBSD patients with dementia. ► Impaired speech fluency was associated with deficits in executive functioning. ► Reduced speech fluency was related to prefrontal cortical atrophy.