A Fully-Immersive Virtual Reality Setup to Study Gait Modulation

Abstract

Objective: Gait adaptation to environmental challenges is fundamental for independent and safe community ambulation. The possibility of precisely studying gait modulation using standardized protocols of gait analysis closely resembling everyday life scenarios is still an unmet need.Methods: We have developed a fully-immersive virtual reality (VR) environment where subjects have to adjust their walking pattern to avoid collision with a virtual agent (VA) crossing their gait trajectory. We collected kinematic data of 12 healthy young subjects walking in real world (RW) and in the VR environment, both with (VR/A+) and without (VR/A-) the VA perturbation. The VR environment closely resembled the RW scenario of the gait laboratory. To ensure standardization of the obstacle presentation the starting time speed and trajectory of the VA were defined using the kinematics of the participant as detected online during each walking trial.Results: We did not observe kinematic differences between walking in RW and VR/A-, suggesting that our VR environment per se might not induce significant changes in the locomotor pattern. When facing the VA all subjects consistently reduced stride length and velocity while increasing stride duration. Trunk inclination and mediolateral trajectory deviation also facilitated avoidance of the obstacle.Conclusions: This proof-of-concept study shows that our VR/A+ paradigm effectively induced a timely gait modulation in a standardized immersive and realistic scenario. This protocol could be a powerful research tool to study gait modulation and its derangements in relation to aging and clinical conditions.

Dynamic evaluation of spine kinematics in individuals with Parkinson’s disease and freezing of gait

“…This could justify the occurrence of freezing episodes when trunk action is needed to execute the motor program (e.g. during turning [49] or gait modulation [42]). During walking, excessive trunk rigidity would also prevent the attenuation of forces exchanged during locomotion and thus proper stabilization of the head, explaining the inability of fall-prone patients to cope with challenging walking conditions [16].…”

“…For walking trials, left and right heel contacts were identified based on the heel vertical trajectories, and the left and right gait cycles were defined. Only gait cycles at steady-state velocity were selected for further analyses, as described in [42]. No patient experienced gait freezing during linear walking.…”

Gait-related cross-frequency coupling in the subthalamic nucleus of parkinsonian patients

“…Similar reasoning can be applied to freezing of gait [76], where it is necessary to distinguish the actual episode of gait freezing from the component of standing while freezing, and attempting to overcome the freezing episode, as well as the physiological neural activity related to gait modulation [35]. This aspect has not yet been studied in a precise and standardized method [77].…”

Long-term improvement of gait with adaptive deep brain stimulation in a patient with Parkinson’s disease

“…Four markers were placed bilaterally on the two feet on the main anatomical landmarks (heels, outer ankle bones, fifth metatarsi and hallux tips) to allow the identification of gait cycle events (heel off and toe off) and the computation of gait spatiotemporal parameters. 46 During gait initiation, three additional markers were attached to the pelvis (on the anterior superior iliac spines and the middle point between the posterior superior iliac spines) to allow the estimation of the centre of mass (CoM). 46 During standing we computed the centre of pressure (CoP) trajectory length, medio-lateral and anterior-posterior range of oscillation, and the confidence ellipse 47 , as measures of balance control 47 .…”