Introduction: Stroke is a leading cause of long-term disability and can result in cognitive and motor impairments. Exercise may improve cognition and motor function after stroke, but past research has typically targeted these impairments in isolation. Here, we investigated whether pairing multiple bouts of exercise with motor practice can positively affect both cognitive and motor function after stroke. Methods: Thirty-three individuals with chronic stroke and 41 healthy older adults completed 5 separate days of motor task practice using their paretic/non-dominant arm, paired with 23 minutes of either high-intensity interval training exercise or rest. Cognitive and motor function were tested pre- and post-intervention. Processing speed, visuospatial skills, and inhibitory control was tested with the Trail Making Test-A and B (TMT-A, TMT-B) and object hit and avoid. Total completion time from TMT-A and TMT-B, target and distractor hits from object hit and avoid were used as dependent measures for assessing cognitive function. For individuals with stroke, motor impairment and function were tested with the Fugl-Meyer upper extremity arm assessment and Wolf Motor Function Test respectively. Results: All participants showed evidence of motor learning; exercise did not confer an additional benefit beyond that stimulated by practice for either group. For stroke participants, motor function (p = .047), but not motor impairment, improved over time. The stroke group who exercised before motor practice displayed significant reductions in TMT-A completion time (p = .035). Both stroke and older adults hit more targets in the post- compared to pre-intervention (p < .001), driven by improvements in the affected/non-dominant hand. Importantly, exercise paired with motor practice also led to a reduced number of distractors hit (p = .026) in the object hit and avoid task for both individuals with stroke and older adults. These changes were not at the expense of speed. Discussion: Five days of high-intensity interval training exercise paired with motor practice led to improved processing speed as measured by the TMT-A for individuals with stroke. Both exercise participant groups (stroke and older adults) showed improved visuospatial skills and inhibitory control as measured by object hit and avoid following our intervention. Our findings suggest that exercise paired with motor task practice leads to improved cognitive-motor function in individuals with stroke and older adults. Together, exercise paired with skilled motor practice appears to be a safe and effective means of enhancing cognitive-motor skills after stroke and in older adults.

The authors have declared no competing interest.

NCT02980796

This work was funded by the Canadian Institutes of Health Research (PI L.A.B., PJT-148535). JWA, JF, BC and BL are funded by a Canadian Institutes of Health Research (CIHR) fellowships. JN and JWA were also funded by the Michael Smith Foundation for Health Research.

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