Pervasiveness of speech-language disorders and fatigue in stroke: A systematic scoping review

Background: After a stroke, it is highly likely that an individual will experience substantial fatigue that can significantly affect recovery and function; stroke survivors also have more than a 50% chance of having at least one speech-language disorder. Current reviews of post-stroke fatigue have not provided evidence focused on speech-language disorders or the potential influence they may have on post-stroke fatigue and related recovery. Objectives: The aim of this review was to determine how speech-language disorders are represented in post-stroke fatigue research and to catalogue methods used to identify speech-language disorders and measure fatigue. Methods: A systematic scoping review was conducted to identify studies measuring post-stroke fatigue. To identify these studies, a comprehensive literature search was conducted using relevant databases and grey literature sources, followed by several stages of review that adhered to PRISMA guidelines. We evaluated these studies using pre-established eligibility criteria and extracted data regarding the inclusion/exclusion of persons with speech-language disorders and the assessment methods used. Results: The scoping review analysis was conducted on 161 studies. Of these, 41 (26%) excluded all speech-language disorders, 71 (44%) excluded severe speech-language disorders, and 49 (30%) included participants with speech-language disorders. Of the 120 studies that did not explicitly exclude all speech-language disorders, only 34 were confirmed to report data from at least one person with a speech-language disorder. Further, only 5 studies reported data that could be used to determine a relationship between speech-language disorders and fatigue. Conclusions: Persons with speech-language disorders are underrepresented in post-stroke fatigue research and very few studies have examined the relationship between post-stroke fatigue and speech-language disorders, limiting conclusions that can be drawn. This is problematic because medical professionals relying on this evidence to guide clinical practice are likely to be treating individuals with co-occurring fatigue and speech-language disorders and the current research does not provide enough information about the potential impact of fatigue on speech-language disorders or vice versa. To bridge this gap, we suggest methods of assessment that could provide ways to more accurately 1) reflect the real population in post-stroke fatigue studies, and 2) measure and document fatigue in post-stroke speech-language disorder studies. We also propose the Filter-Funnel Model of Post-Stroke Fatigue, which considers the role of speech-language disorders and communicative demands in the context of post-stroke fatigue.