Effect of Viewing Angle and Object Position on Accuracy of Arm Reaching in a 3D Virtual Environment

Virtual environments permit the creation of rehabilitation settings that help prepare clients for subsequent real world functional activities. Many questions remain regarding the optimal presentation of the environment, one being how manipulation of target position and viewing angle or perspective can affect functional reaching performance. Using twenty healthy young adults (24.7+3.0), this study examined the effect on functional arm reaching by manipulating these factors in a first person 3D virtual hallway. Their goal was to touch a blue pyramidal target without stepping or overbalancing. The target was randomly positioned either directly in front of the participant or offset 10 0 to either side with randomly assigned viewing angles of 10 0 , 45 0 , and 90 0 . Movement was recorded using an Xbox Kinect Motion Sensor. Outcome measures of endpoint error, peak velocity, and index of curvature were calculated. Manipulating the viewing angles had no significant impact on peak velocity, endpoint error, or directness of path to the target. Target positions that required contralateral reaching across the midline of the body increased peak velocities and had a less direct path to the target. Results suggest that for healthy adults, the viewing angle is not a limiting factor in reaching to a target. However, more research is needed to test this in participants with sensorimotor deficits. In our healthy population, reaching across the midline of the body in a 3D environment affects reaching pathway and peak velocity, and knowing this will be helpful in further developing virtual rehabilitation activities. KeywordsGame Platforms; Game Therapy; Rehabilitation; Reaching in Virtual Environments