Subjective visual and haptic vertical in young and elderly

Perception of verticality can be assessed in two different ways: measuring of subjective visual vertical (SVV) and subjective haptic vertical (SHV). The evidence on aging of SVV and SVH is not conclusive and there is just little knowledge focused on this issue. The aim of this study was to compare accuracy of perception of SVV and SHV between groups of young and elderly healthy subjects. SVV examination was performed using the bucket test. An experimental tactile device was used to assess perceived SHV. Measurements of SVV and SHV were made in 27 young healthy and 30 elderly healthy subjects, both groups were right-handed due to self-report. SHV estimated position was significantly different (p< 0.01) in young and elderly (counterclockwise shift of 0.72 ± 3.70° and 3.51 ± 3.99°, respectively) and the SHV range (4.17 ± 5.40° and 9.64 ± 7.42°, respectively) was also different (p< 0.01). The differences were caused by significant difference in the supination maneuver (clockwise rod rotation, p< 0.001) which resulted in counterclockwise shift of 2.80 ± 4.90° and 8.33 ± 4.62° in young and elderly respectively. Pronation part of the SHV task (counterclockwise rod rotation) did not significantly differ between groups. SVV estimated position and range were not statistically different between young and elderly. These results provide evidence that the ability to detect SVV is not impaired, SHV seems also not to be affected by aging but there may be methodologic issues in SHV testing in elderly which should be controlled for in future studies. Results of both pronation and supination maneuvers should be provided along with SHV position.