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Title: Human balance behaviour in immersive virtual environments
Author: Antley, A.
ISNI:       0000 0004 5363 1412
Awarding Body: University College London (University of London)
Current Institution: University College London (University of London)
Date of Award: 2014
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Presence is defined as the illusion of being in a place depicted by an immersive virtual reality (IVR) system. A consequence of this illusion is that participants respond to places and events in an IVR as if they were real. Currently, there is no objective measure of presence that applies across all systems and applications. In this thesis we examine a particular type of response as if real, human balance behaviour (HBB), the actions that prevent the body’s centre of gravity from moving outside the base of support, as a way to measure presence in an IVR. Our first experiment was designed to investigate whether HBB can detect presence in IVRs. We used surface EMG to measure muscle activations and found an increase when subjects walked on a virtual raised platform compared to a virtual floor registered to the laboratory floor. A similar increase was found when subjects walked on a real raised platform. This provides evidence of real HBB induced by an IVR . In a second experiment HBB was used to compare partial-body and full-body tracking configurations. When participants viewed a lateral lean imposed on the torso of a synchronous virtual body (SVB), their stance angle changed in a compensatory direction. We found a weaker negative correlation indicating compensatory leaning in the partial-body tracking condition leaning. This suggests partial-body tracking may dampen the full-body illusion in IVRs. We carried out a case study to show the relevance of HBB for IVRs used for movement rehabilitation. Hemiparetic stroke patients observed a SVB that was colocated with their own. When an animation caused their virtual arms to rise up, we found evidence of counterbalancing in centre of pressure data that was not apparent when the subjects were told to simply imagine the movement. Here HBB directly indicates the effectiveness of an IVR application.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available