Modulation of gait speed (dotted lines) as a function of optic flow speed (plain lines) in a healthy subject (A) and subjects with stroke presenting with a slow (B) and a faster walking speed (C). Data were analyzed once the subjects reached their comfortable speed, as indicated by the vertical dashed lines. Left and right y-axes are for optic flow speed and gait speed, respectively. Note the different y-axis scales amongst the subjects.
Lamontagne et al. Journal of NeuroEngineering and Rehabilitation 2007 4:22 doi:10.1186/1743-0003-4-22