Towards understanding and improving gait rehabilitation in virtual environments using latency for persons with mobility impairments
Latency is an unavoidable byproduct of the modern virtual reality systems. Although it has been highly studied for several decades, the effects of latency and how it is perceived by persons suffering from mobility impairments have not been investigated. It is important to understand the effects latency has on such under-investigated populations (e.g. persons suffering from Multiple Sclerosis) with the increasing use of virtual reality technology in physical rehabilitation techniques. Therefore, the first study was conducted aiming at understanding the influences of latency and the presence of an avatar have on persons suffering from mobility impairments. The results showed that most participants failed to notice even the higher latency conditions present in the virtual environment, even though their gait was altered. To investigate the lack of latency detection noted, a second study was carried out to examine how the latency thresholds of participants suffering from Multiple Sclerosis may differ from healthy participants. The results showed considerably higher tolerance for latency in participants suffering from multiple sclerosis than healthy participants. Thus, I raised the following question: "can latency be used to create a perceptual illusion to effectively improve rehabilitation in persons suffering from mobility impairments?" To investigate, I conducted two additional experiments where differing latency levels are applied to the left and right side of a self-avatar with both healthy and participants with mobility impairments. The results showed the potential of manipulating walking patterns using latency in a virtual environment. Here, I report the results of these experiments and the implications they have in general virtual rehabilitation system design as well as gait rehabilitation for asymmetric gait. Latency can thus be potentially used as a gait altering technique in a virtual environment.