Magnifying vision improves motor performance in individuals with stroke.

Increasing perceived hand size using magnifying lenses improves tactile discrimination and motor performance in neurologically-intact individuals. We tested whether magnification of the hand can improve motor function in individuals with chronic stroke. Twenty-five individuals with a history of stroke more than 6 months prior to testing underwent a series of tasks exploring different aspects of motor performance (grip force, finger tapping, reaching and grasping, and finger matching) under two visual conditions: magnified or normal vision. Performance was also assessed shortly after visual manipulation to test if these effects persisted. Twenty-eight percent of individuals showed an immediate significant improvement averaged across all tasks with magnification; similar beneficial responses were also observed in 32% of individuals after a short delay. These results suggest that magnification of the image of the hand may be of utility in rehabilitation of individuals with stroke.