Introduction: Perception of self-motion through virtual reality (VR) provides a unique avenue to improve gait adaptation in chronic stroke survivors. In this ongoing study, stroke survivors adapted to a split-belt paradigm and perception of self-motion was provided in a VR environment. It was hypothesized that the relationship between baseline spatio-temporal asymmetry and gait adaptation would be different in VR than Non-VR (control) groups.
Methods: Chronic stroke survivors (n=24; age=59.5±13.68years) participated in a split-belt adaptation paradigm and were randomly put into a VR or a Non-VR group. The recruited subjects included a wide range in lower limb Fugl-Meyer scores (11-46) and baseline gait asymmetries (spatial: -17% to +44%, temporal: -16% to +39%). The adaptation trials exposed the participants to different belt speeds for each leg. In addition, pre- and post-adaptation treadmill trials were performed at the participants’ preferred walking speed. The VR stimuli consisted of walking in an infinitely long virtual corridor. Spatiotemporal measures (step length and step time asymmetries) as correlates of adaptation were compared with baseline asymmetries using Pearson correlation coefficients.
Results: Step length asymmetry during adaptation showed a significant relationship with baseline asymmetry only for the VR (r=0.722, p=0.012) but not the Non-VR group (r=-0.457, p=0.116). During transfer, a significant relationship was shown for both VR (r=0.752, p=0.008) and Non-VR (r=-0.616, p=0.025) groups. However, this relationship was positive for VR and negative for Non-VR. Step time asymmetry during adaptation showed a borderline relationship with baseline asymmetry only for the VR (r=0.569, p=0.068) but not the non-VR group (r=-0.014, p=0.964). During transfer, a significant relationship was shown only for the VR (r=0.614, p=0.045) but not the non-VR (r=-0.366, p=0.218) group.
Discussion: The results indicated a potentially greater impact of VR in stroke survivors with high levels of spatial and/temporal gait asymmetries. Future studies will investigate the magnitude and mechanisms of this impact. This will help VR-based gait rehabilitation to be stratified and streamlined for greater benefit.