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Representation of people with aphasia in randomized controlled trials of acute stroke interventions


  • Conflict of interest: None declared.
  • Funding: M. A., M. B., and the Nursing, Midwifery and Allied Health Professions Research Unit are funded by the Chief Scientist Office (CSO) Scottish Government's Health Directorate, Scotland. This work was funded as part of a CSO Post-Doctoral Fellowship Award. The views expressed here are those of the authors and not necessarily those of the CSO. VISTA is a not-for-profit collaboration of researchers from academia and commercial organizations. The VISTA Steering Committee members have each contributed to the organization of contributing trials, and where these have involved industry support, they have acknowledged that within the original publications.



Aphasia affects up to a third of the stroke population and is associated with poor social participation and quality of life. Yet people with aphasia may be excluded from some types of stroke research due to challenges in informing, consenting, and conducting follow-up in this population.

Aims and/or hypothesis

We described the representation of those with aphasia in acute stroke clinical research, the level of inclusion across international trial sites, and whether there have been improvements in the inclusion of this population in recent clinical trials.


We conducted a retrospective analysis of clinical trial data from the Virtual International Stroke Trials Archive (VISTA), defining aphasia using the Best Language (item 9) domain of the National Institutes of Health Stroke Scale. We used proportional odds modeling, adjusting for age, gender, ethnicity, stroke severity, medical history, hemisphere affected by stroke, and trial eligibility criteria, to examine the associations between year, location of enrollment, inclusion, and attrition of those with aphasia.


Data were available for 8904 patients from 10 trials; no trials listed aphasia as an exclusion criterion. At baseline, aphasia was present in 4039 (45·4%); severe/global aphasia was present in 2688 (30·2%). We observed no geographic or longitudinal disparity in the attrition of these patients at three-months. Centers in the Philippines recruited fewer people [P = 0·05, odds ratio = 0·5, 95% confidence interval (0·2, 1·0)], while centers in Central and South America included more people with severe/global aphasia [P = 0·0004, odds ratio = 2·4, 95% confidence interval (1·3, 4·3)], when compared with centers in the USA and Canada.


Acute stroke trials have demonstrated the feasibility of including people with aphasia in stroke research; we observed geographic variations that were not entirely explained by case mix or trial eligibility criteria. Similar levels of inclusion should be sought in nonemergency stroke trials to improve the applicability of research findings to this population.