Subjective visual vertical (SVV) assesses visual dependence for spacial orientation, by the use of vertical perception testing. Using the computerized rod-and-frame test (CRFT), SVV is considered to be an important measure of cervical proprioception and might be greater in those with whiplash associated disorder (WAD), but to date research findings are inconsistent. The objective of this study was to investigate the most sensitive SVV error measurement to detect group differences between no neck pain control, idiopathic neck pain (INP) and WAD subjects. The INP group had significantly (p<0.03) greater VE and RMSE in comparison to both the control and WAD groups. There were no differences seen between the WAD and controls.
The results showed that people with INP (not WAD), had an altered strategy for maintaining the perception of vertical by increasing variability of performance. This may be because of the complexity of the task. Further, the SVV performance was not associated to reported pain or dizziness handicap. These findings are inconsistent with other measures of cervical proprioception in neck pain and more research is necessary before the SVV can be considered an important measure and utilized clinically.