Abstract
We have previously reported that anxiety increases body sway in college students during orthostatic standing (Wada et al, 2001; Ohno et al., 2004). In the present experiment, relationship between the body sway and the degree of anxiety was explored in 11 healthy participants while standing with a visual target changing in size. The size of visual target continuously varied between 5.34° and 8° in visual angle with a frequency of 0.3 Hz. Body sway recorded was computed by FFT analysis, and the power of the four frequency bands (0.02-0.1 Hz, 0.1-0.21 Hz, 0.21-1 Hz and 1-10 Hz) were calculated on the basis of frequency properties of sensory inputs affecting postural balance. A negative correlation between the degree of anxiety and the power of the frequency band of 0.1-0.21 Hz in the left-right axis of body sway was found to be statistically significant (r= -0.68, p<0.05). No correlation was found between anxiety and any of the frequency powers in participants with a stable target with visual angle of 8°. It has been postulated that sensory inputs from the vestibular organs stabilizes the body sway with 0.1-0.21 Hz (Redfern et al., 2001). Therefore, the present result has raised a possibility that anxiety increases the recruitment of vestibular inputs to maintain the postural balance when the visual angle is periodically changing. [J Physiol Sci. 2007;57 Suppl:S190]
