The impact of visual flow stimulation on anxiety, dizziness, and body sway in individuals with and without fear of heights

Individuals with acrophobia experience anxiety and dizziness when exposed to heights. It may be that their balance system is disturbed and that they therefore have to rely more strongly on visual information. We tested this hypothesis by exposing 20 individuals with high fear of heights and 20 healthy control participants to nine different visual flow stimuli through a head mounted display, thereby inducing a conflict between visual input and somatosensory information. Anxiety and dizziness were assessed repeatedly by means of self-reports, while resultant body sway was measured continuously with a force plate individuals stood on. Individuals with fear of heights felt more anxious and dizzier, and also showed stronger body sway than healthy control participants. Merely receiving visual balance information contradictory to somatosensory balance information is sufficient to induce anxiety, dizziness, and body sway in individuals with fear of heights. An underlying balance dysfunction may contribute to the development of height phobia. (C) 2009 Elsevier Ltd. All rights reserved.