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Session: Poster session II
Session starts: Thursday 24 January, 16:00

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Marjolein van der Krogt (1) Department of Rehabilitation Medicine, Research Institute MOVE, VU University Medical Center, PO Box 7057, 1007 MB Amsterdam, The Netherlands & 2) Lab. of Biomechanical Engineering, University of Twente, Enschede, The Netherlands )
Lianne Kraan (Faculty of Human Movement Sciences, VU University, Amsterdam, The Netherlands)
Tessa Hoekstra (Faculty of Human Movement Sciences, VU University, Amsterdam, The Netherlands)
Jaap Harlaar (Department of Rehabilitation Medicine, Research Institute MOVE, VU University Medical Center, PO Box 7057, 1007 MB Amsterdam, The Netherlands )

Abstract:
GRAIL (Gait Real-time Analysis Interactive Lab, Motek Medical BV) is a newly developed tool for real-time gait analysis and gait training. It combines an instrumented dual-belt treadmill with a Virtual Reality (VR) environment (180o semi-cylindrical screen) and 3D motion capture. GRAIL allows for direct interaction with the subject, for instance to adjust the belt speed to the subject’s self-chosen walking speed. Previous studies have indicated that fixed-speed treadmill mode and lack of visual flow are potential causes for differences in gait parameters between overground and treadmill walking. The aim of this study was to investigate whether walking on the GRAIL in a self-paced mode with VR is similar to overground walking in terms of spatiotemporal and kinematic parameters. Ten typically developing children (age 8-15y, 7 male, 3 female) walked at their own preferred walking speed, both on the GRAIL and overground in a conventional gait lab, within the same session. Spatiotemporal parameters and 3D kinematics (Optotrak, Northern Digital Inc) were compared, as quantified by 17 key gait parameters and the Gillette Gait Index (GGI) [1]. Walking speed and cadence did not differ significantly between GRAIL and overground walking, while step width was somewhat higher on the GRAIL (0.10m vs 0.07m, p<0.05). Kinematic patterns were very similar, and most parameters did not differ significantly between GRAIL and overground walking. However, some significant differences were found: on the GRAIL, peak ankle dorsiflexion in swing was smaller, the hip was slightly more abducted in swing (right leg only), and more exorotated in stance (left leg only). All mean differences were in the order of 1-3 degrees. GGI scores were significantly higher on the GRAIL (right 53.2, left 31.1 versus 15.7 for both left and right overground). In conclusion, GRAIL and overground walking were very similar, but differences were found in step width and some kinematic parameters. Most differences were small, and likely not clinically significant. These findings indicate that GRAIL walking may be used instead of overground walking, but further study is needed. In ongoing analyses, we are investigating the individual effects of VR and self-paced treadmill mode on gait parameters, as well as the effects on kinetics. Furthermore, to evaluate the applicability for clinical gait analysis, we are studying GRAIL versus overground walking in children with cerebral palsy.