A Novel Virtual Reality Paradigm to Assess Gait Response to Visuospatial Perturbation during Walking

Response to a dynamically altering environment while ambulating is critical for walking performance. The optimum outcome of the response is to maintain gait stability and balance. In this regard, the human propensity to spontaneously react to visuospatially triggering perturbations while walking overground is relatively under-explored. Virtual reality system presents technical precedence to three-dimensionally simulate visuospatial perturbation during walking and study the gait behavior in response to a sudden perturbation. In this study, two experimental conditions in the virtual environment were designed - baseline free walking and walking with target visuospatial stimuli as a perturbation. Walking was performed overground in laps of six meters. Three healthy young adults were recruited (mean age: 23.2 ± 2.0 years). Participants wore virtual reality headset and trackers to obtain their gait characteristics. Results showed that participants walked with consistent gait strides in the baseline condition of free walking. In the other perturbation condition, gait features changed significantly (reduced stride lengths, step lengths, and increased stride widths) in the vicinity of visuospatially delivered perturbation. Post reaction to the stimulus, participants walked with a baseline-like consistent gait. Moreover, as overground lap walking progressed, participants were able to anticipate the stimulus's cueing with conservative walking relative to free walking. These results demonstrate the novel implementation of a virtually simulated visuospatial perturbation delivery paradigm with gait characterization to quantify human response. This VR-based paradigm can be used to study and compare the response to sudden visuospatial perturbation while walking in different population groups and provide insights to safeguard them against perturbation effects such as falls.