Importance: A stroke doubles one's risk for dementia. How to promote cognitive function among persons with chronic stroke is unclear.
Objective: To evaluate the effect of exercise (EX) or cognitive and social enrichment activities (ENRICH) on cognitive function in adults with chronic stroke.
Design, setting, and participants: This was a 3-group parallel, single-blinded, single-site, proof-of-concept randomized clinical trial at a research center in Vancouver, British Columbia, Canada. Participants included community-dwelling adults with chronic stroke, aged 55 years and older, able to walk 6 meters, and without dementia. The trial included a 6-month intervention and a 6-month follow-up. Randomization occurred from June 6, 2014, to February 26, 2019. Measurement occurred at baseline, 6 months, and 12 months. Data were analyzed from January to November 2021.
Interventions: Participants were randomly allocated to twice-weekly supervised classes of: (1) EX, a multicomponent exercise program; (2) ENRICH, a program of cognitive and social enrichment activities; or (3) balance and tone (BAT), a control group that included stretches and light-intensity exercises.
Main outcomes and measures: The primary outcome was the Alzheimer Disease Assessment Scale-Cognitive-Plus (ADAS-Cog-Plus), which included the 13-item ADAS-Cog, Trail Making Test Parts A and B, Digit Span Forward and Backward, Animal Fluency, and Vegetable Fluency.
Results: One-hundred and twenty participants, with a mean (range) of 1.2 (1-4) strokes, a mean (SD) of 66.5 (53.8) months since the most recent stroke, mean (SD) baseline age of 70 (8) years, mean (SD) baseline ADAS-Cog-Plus of 0.22 (0.81), and 74 (62%) male participants, were randomized to EX (34 participants), ENRICH (34 participants), or BAT (52 participants). Seventeen withdrew during the 6-month intervention and another 7 during the 6-month follow-up. Including all 120 participants, at the end of the 6-month intervention, EX significantly improved ADAS-Cog-Plus performance compared with BAT (estimated mean difference: -0.24; 95% CI, -0.43 to -0.04; P = .02). This difference did not persist at the 6-month follow-up (estimated mean difference: -0.08; 95% CI, -0.29 to 0.12; P = .43). For the 13-item ADAS-Cog, the EX group improved by 5.65 points over the 6-month intervention (95% CI, 2.74 to 8.57 points; P < .001), exceeding the minimally clinical difference of 3.0 points.
Conclusions and relevance: These findings suggest that exercise can induce clinically important improvements in cognitive function in adults with chronic stroke. Future studies need to replicate current findings and to understand training parameters, moderators, and mediators to maximize benefits.
Trial registration: ClinicalTrials.gov identifier: NCT01916486.