Fig 1.
Subject setup and virtual reality views.
Typical subject setup is shown (left). All subjects walked on the same physical beam for all three conditions. In both virtual reality conditions, subjects saw a virtual beam that aligned with the physical beam. In virtual reality low, the virtual beam was the same height off the ground as in unaltered view low (top right), while the virtual beam was 15 meters off the ground in virtual reality high (bottom right).
Fig 2.
EEG source localization results.
EEG source localization results are shown for the 8 cortical clusters found across all subjects (n = 19). Dipole locations (top) and cluster centroids (bottom) are shown in transverse, sagittal, and coronal views (left to right). We found clusters in anterior parietal (purple), left sensorimotor (blue), right frontal (maroon), anterior cingulate (green), medial occipital (yellow), supplementary motor area (orange), left posterior parietal (red), and right sensorimotor (cyan).
Table 1.
Motion sickness assessment results.
Table 2.
Behavioral and physiological measures.
Table 3.
Sitting/standing experiment results.
Fig 3.
Percent change in failures per minute, heart rate, and response time.
To assess fatigue effects, we calculated the percent change (mean±SE) between the first and last 3 minutes of each condition (n = 19). Failures per minute, heart rate, and response time are shown for unaltered view low (red), virtual reality low (dark blue), and virtual reality high (light blue). Negative percent change indicates that the value in the final 3 minutes decreased compared to the first 3 minutes. Failures per minute percent change significantly decreased in unaltered view low compared to virtual reality low. Heart rate percent change significantly increased in virtual reality high compared to virtual reality low. No other comparisons were significant between 1) unaltered view low vs. virtual reality low and 2) virtual reality low vs. virtual reality high.
Fig 4.
EEG event-related activity for cortical clusters.
EEG event-related activity is shown for each cortical cluster (n = 19), with unaltered view low in red and virtual reality low in blue. Tone presentation occurred at 0 ms, preceded by 300 ms of baseline activity. We analyzed 800 ms following the tone presentation. Shading reflects the condition with significantly higher amplitude (red for unaltered view low, blue for virtual reality low). We found significant differences in the anterior cingulate cluster only.