Effects of odors on posture

Abstract

Evidence suggests that postural stability may benefit from olfactory exposure, but whether this effect is different for hyposmic and healthy subjects remains unknown and little attention has been paid to the hedonic valence of odors in this context. Forty-five participants aged between 23 and 64 years were invited to this study, of whom 32 had normal olfactory function 13 exhibited olfactory deficits. Movement measurements were performed with the “Unterberger stepping test.” Participants walked in place with stretched arms for 8 periods of 30 s each, separated by intervals of approximately 15 s. During each of these 30-s blocks one of the three odor conditions was presented to them: (a) pleasant odor, (b) unpleasant odor, and (c) odorless control. Both participants with normosmia and impaired olfaction moved to the left and right sides more when exposed to the unpleasant odor as compared to pleasant odor exposure or no odor. When smelling pleasant odors, participants presented shorter maximal anterior/posterior sway than during no odor exposure, but it was similar when smelling unpleasant odor. The study demonstrated strong effects of odors on postural stability with pleasant odors limiting and unpleasant enhancing postural sways. Practical Applications: Odors affect postural stability. Although we fail to demonstrate that postural stability measurements can be applied as a supporting method in smell dysfunction diagnosis, the current study opens prospects for further explorations of the relationship between olfactory and vestibular systems. These efforts may eventually lead to practical solutions supporting postural balance in patients suffering from conditions adversely affecting the vestibular system.