Does treadmill exercise improve performance of cognitive or upper-extremity tasks in people with chronic stroke? A...

To determine whether acute exercise, using a body-weight-supported treadmill, improves performance on subsequent cognitive tests or an upper-extremity task in people with stroke.

The study was a within-subject, cross-over design in which 21 subjects received, randomly, 2 different testing sequences separated by an interval of 7 to 10 days.

Outpatient department of a rehabilitation hospital.

Of 72 potential participants in the convenience sample, 21 people with chronic stroke completed the study. They were 0.5 to 5 years after only 1 documented stroke, were able to walk with or without a cane, were able to grasp with the affected hand, and scored more than 24 on the Mini-Mental State Examination.

One session of body-weight-supported treadmill walking for 20 minutes at 70% of estimated heart rate reserve or level 13 on the Borg rating of perceived exertion scale. The control condition consisted of a 20-minute review of a home exercise program with a physiotherapist.

Cognitive tests included Trail Making Tests Parts A and B, Symbol Digit Substitution Test, and Paced Auditory Serial Addition Test. The Action Research Arm Test (ARAT) measured hemiplegic upper-extremity motor skill.

Treadmill exercise improved movement of the hemiplegic upper extremity (P=.04) but not cognitive performance. The improvement in the ARAT occurred without a change in strength (measured by grip strength) and was negatively correlated with maximum treadmill speed (R(2)=.20; P=.04).

These findings suggest that acute treadmill exercise improves subsequent skilled movement of the hemiplegic upper extremity that seems unrelated to attention, visuomotor processing, or strength. The etiology and duration of this enhancing effect are worth further study. The existence of an exercise-cognition relationship in people with stroke is an intriguing area of future research.