The use of a neck brace does not influence visual vertical perception

摘要

Subjective visual vertical (SVV) evaluates the individual's capacity to determine the vertical orientation. Using a neck brace (NB) allow volunteers' heads fixation to reduce cephalic tilt during the exam, preventing compensatory ocular torsion and erroneous influence on SVV result. OBJECTIVE: To analyze the influence of somatosensory inputs caused by a NB on the SVV. METHOD: Thirty healthy volunteers performed static and dynamic SVV: six measures with and six without the NB. RESULTS: The mean values for static SVV were -0.075o±1.15o without NB and -0.372o±1.21o with NB. For dynamic SVV in clockwise direction were 1.73o±2.31o without NB and 1.53o±1.80o with NB. For dynamic SVV in counterclockwise direction was -1.50o±2.44o without NB and -1.11o±2.46o with NB. Differences between measurements with and without the NB were not statistically significant. CONCLUSION: Although the neck has many sensory receptors, the use of a NB does not provide sufficient afferent input to change healthy subjects' perception of visual verticality.