Data from one participant were not analyzed due to inability to perform the Sharpened Romberg task, particularly in the occluded condition. The data from the remaining fourteen participants are summarized in Table 6.2.4.
| Condition | ||
| Measure | See-through | Occluded |
| SSQ * | 15.0(16.0) | 18.7(24.5) |
| Total Stance Breaks * | 4.1(4.8) | 9.1(8.2) |
| SB1 | 1.1(1.5) | 3.9(3.2) |
| SB3 | 3.0(3.6) | 5.2(5.5) |
| Vection | 3.5/7.0(1.7) | 3.5/7.0(1.9) |
| Background Visibility | 2.0/5.0(0.6) | N/A |
``SSQ'' is a reported simulator sickness value [55]. ``SB1'' and ``SB3'' are the total number of stance breaks in the first and third minute, respectively. For the skewed data (SSQ, vection and visibility ratings), medians are reported. Other values are means. Standard deviations are given in parentheses. ``*'' implies that the difference between conditions is significant at p < .05.
The stance break data passed tests of normality and homogeneity. Total stance breaks, SB1 and SB3 were analyzed with a 2-tail paired t-test. The questionnaire data, SSQ and vection ratings, were analyzed using a non-parametric, 2-tail paired Wilcoxon.
Both SSQ (p < .05) and total stance breaks (p < .03) were significantly lower in the see-through than the occluded condition. Pooling across conditions, there were significantly fewer stance breaks in SB1 than SB3 (p < .03), indicating increased ataxia as the experiment progressed. There was a weak trend for higher vection in the occluded condition (p < .14).
A weak trend was found for an overall order effect for total stance breaks, with the first condition more difficult (p < .13).