Using the "VREye" system for the assessment of unilateral visual neglect: Two case reports

Unilateral visual neglect (UVN) is the inability of patients, with damage t o their left or right cerebral hemisphere, to respond to stimuli presented on the side opposite the lesion. We present a preliminary study on using a HMD-based-eye-tracking system for the assessment of UVN. Normal subjects an d patients with UVN were shown two virtual environment (VE) scenes. The sub jects were required to identify and count the objects in scene I, and to id entify a clock and tell the time in scene 2. Eye movements of these subject s were recorded during the task There were differences in the amount of vis ual field scanned by the subjects and patients. The normal subjects scanned the entire scene and identified all the objects. Patients with left UVN di d not scan the left side of the scene and did not report objects on that si de. Patients with right UVN scanned only the left side of the scene and did not report objects on the right side of the scene. This study demonstrates the feasibility of using the HMD-based eye-tracking system in a virtual en vironment for characterizing UVN.