Effects of shading and droplines on object localization in virtual rehabilitation for patients with neurological conditions

Virtual environments (VE) are emerging for the creation of effective and motivating exercise therapy for neurorehabilitation of MS and stroke patients. Although these interactive systems are promising tools in rehabilitation, the targeted end users often suffer from visual system disorders and cognitive dysfunctions, which may influence their capabilities while navigating in a virtual 3D world. Cues like shades are proven to be effective navigation and localization aids in a 3D environment for healthy people, but little is known about their benefit for persons with a neurological disease. Therefore, we conducted a user study to test the impact of visual cues such as shading on navigation tasks in a VE for a population of MS and stroke patients. We compared 3 visual conditions in the environment: one without shading, one with shading, and one with shading as well as a dropline between the shade and the object representing the person's location in the environment. Participants in the user study were 11 persons diagnosed with MS, 9 with stroke and 9 healthy control persons. Subjective measures were not uninfluenced by the use of shade or a dropline, but objective measures show a significant increase in speed, and lower execution time resulting from the addition of object-shading.