Individuals Poststroke Do Not Perceive Their Spatiotemporal Gait Asymmetries as Abnormal.

Abstract

Following stroke, spatiotemporal gait asymmetries persist into the chronic phases, despite the neuromuscular capacity to produce symmetric walking patterns. This persistence of gait asymmetry may be due to deficits in perception, as the newly established asymmetric gait pattern is perceived as normal. The purpose of this study was to determine the effect of usual overground gait asymmetry on the ability to consciously and unconsciously perceive the presence of gait asymmetry in people poststroke. An observational study was conducted. Thirty people poststroke walked overground and on a split-belt treadmill with the belts moving at different speeds (0%-70% difference) to impose varied step length and stance time asymmetries. Conscious awareness and subconscious detection of imposed gait patterns were determined for each participant, and the asymmetry magnitudes at those points were compared with overground gait. For both spatial and temporal asymmetry variables, the asymmetry magnitude at the threshold of awareness was significantly greater than the asymmetry present at the threshold of detection or during overground gait. Participants appeared to identify belt speed differences using the type of gait asymmetry they typically exhibited (ie, step length or stance time asymmetries during overground gait). Very few individuals with severe spatiotemporal asymmetry were tested, and participants were instructed to identify asymmetric belt speeds rather than interlimb movements. The data suggest that asymmetry magnitudes need to exceed usual overground levels to reach conscious awareness. Therefore, it is proposed that the spatiotemporal asymmetry that is specific to each participant may need to be augmented beyond what he or she usually has during walking in order to promote awareness of asymmetric gait patterns for long-term correction and learning.